13 files changed, 586 insertions, 25 deletions

diff --git a/Makefile b/Makefile
index 4e101d3..f8a4d47 100644
--- a/Makefile
+++ b/Makefile
@@ -1,180 +1,181 @@
 CGIT_VERSION = v0.8.3
 CGIT_SCRIPT_NAME = cgit.cgi
 CGIT_SCRIPT_PATH = /var/www/htdocs/cgit
 CGIT_DATA_PATH = $(CGIT_SCRIPT_PATH)
 CGIT_CONFIG = /etc/cgitrc
 CACHE_ROOT = /var/cache/cgit
 SHA1_HEADER = <openssl/sha.h>
 GIT_VER = 1.6.4.3
 GIT_URL = http://www.kernel.org/pub/software/scm/git/git-$(GIT_VER).tar.bz2
 INSTALL = install
 
 # Define NO_STRCASESTR if you don't have strcasestr.
 #
 # Define NO_OPENSSL to disable linking with OpenSSL and use bundled SHA1
 # implementation (slower).
 #
 # Define NEEDS_LIBICONV if linking with libc is not enough (eg. Darwin).
 #
 
 #-include config.mak
 
 #
 # Platform specific tweaks
 #
 
 uname_S := $(shell sh -c 'uname -s 2>/dev/null || echo not')
 uname_O := $(shell sh -c 'uname -o 2>/dev/null || echo not')
 uname_R := $(shell sh -c 'uname -r 2>/dev/null || echo not')
 
 ifeq ($(uname_O),Cygwin)
         NO_STRCASESTR = YesPlease
         NEEDS_LIBICONV = YesPlease
 endif
 
 #
 # Let the user override the above settings.
 #
 -include cgit.conf
 
 #
 # Define a way to invoke make in subdirs quietly, shamelessly ripped
 # from git.git
 #
 QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
 QUIET_SUBDIR1  =
 
 ifneq ($(findstring $(MAKEFLAGS),w),w)
 PRINT_DIR = --no-print-directory
 else # "make -w"
 NO_SUBDIR = :
 endif
 
 ifndef V
         QUIET_CC       = @echo '   ' CC $@;
         QUIET_MM       = @echo '   ' MM $@;
         QUIET_SUBDIR0  = +@subdir=
         QUIET_SUBDIR1  = ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
                          $(MAKE) $(PRINT_DIR) -C $$subdir
 endif
 
 #
 # Define a pattern rule for automatic dependency building
 #
 %.d: %.c
         $(QUIET_MM)$(CC) $(CFLAGS) -MM $< | sed -e 's/\($*\)\.o:/\1.o $@:/g' >$@
 
 #
 # Define a pattern rule for silent object building
 #
 %.o: %.c
         $(QUIET_CC)$(CC) -o $*.o -c $(CFLAGS) $<
 
 
 EXTLIBS = git/libgit.a git/xdiff/lib.a -lz
 OBJECTS =
 OBJECTS += cache.o
 OBJECTS += cgit.o
 OBJECTS += cmd.o
 OBJECTS += configfile.o
 OBJECTS += html.o
 OBJECTS += parsing.o
 OBJECTS += scan-tree.o
 OBJECTS += shared.o
 OBJECTS += ui-atom.o
 OBJECTS += ui-blob.o
 OBJECTS += ui-clone.o
 OBJECTS += ui-commit.o
 OBJECTS += ui-diff.o
 OBJECTS += ui-log.o
 OBJECTS += ui-patch.o
 OBJECTS += ui-plain.o
 OBJECTS += ui-refs.o
 OBJECTS += ui-repolist.o
 OBJECTS += ui-shared.o
 OBJECTS += ui-snapshot.o
+OBJECTS += ui-ssdiff.o
 OBJECTS += ui-stats.o
 OBJECTS += ui-summary.o
 OBJECTS += ui-tag.o
 OBJECTS += ui-tree.o
 
 ifdef NEEDS_LIBICONV
         EXTLIBS += -liconv
 endif
 
 
 .PHONY: all libgit test install uninstall clean force-version get-git \
         doc man-doc html-doc clean-doc
 
 all: cgit
 
 VERSION: force-version
         @./gen-version.sh "$(CGIT_VERSION)"
 -include VERSION
 
 
 CFLAGS += -g -Wall -Igit
 CFLAGS += -DSHA1_HEADER='$(SHA1_HEADER)'
 CFLAGS += -DCGIT_VERSION='"$(CGIT_VERSION)"'
 CFLAGS += -DCGIT_CONFIG='"$(CGIT_CONFIG)"'
 CFLAGS += -DCGIT_SCRIPT_NAME='"$(CGIT_SCRIPT_NAME)"'
 CFLAGS += -DCGIT_CACHE_ROOT='"$(CACHE_ROOT)"'
 
 ifdef NO_ICONV
         CFLAGS += -DNO_ICONV
 endif
 ifdef NO_STRCASESTR
         CFLAGS += -DNO_STRCASESTR
 endif
 ifdef NO_OPENSSL
         CFLAGS += -DNO_OPENSSL
         GIT_OPTIONS += NO_OPENSSL=1
 else
         EXTLIBS += -lcrypto
 endif
 
 cgit: $(OBJECTS) libgit
         $(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o cgit $(OBJECTS) $(EXTLIBS)
 
 cgit.o: VERSION
 
 -include $(OBJECTS:.o=.d)
 
 libgit:
         $(QUIET_SUBDIR0)git $(QUIET_SUBDIR1) NO_CURL=1 $(GIT_OPTIONS) libgit.a
         $(QUIET_SUBDIR0)git $(QUIET_SUBDIR1) NO_CURL=1 $(GIT_OPTIONS) xdiff/lib.a
 
 test: all
         $(QUIET_SUBDIR0)tests $(QUIET_SUBDIR1) all
 
 install: all
         $(INSTALL) -m 0755 -d $(DESTDIR)$(CGIT_SCRIPT_PATH)
         $(INSTALL) -m 0755 cgit $(DESTDIR)$(CGIT_SCRIPT_PATH)/$(CGIT_SCRIPT_NAME)
         $(INSTALL) -m 0755 -d $(DESTDIR)$(CGIT_DATA_PATH)
         $(INSTALL) -m 0644 cgit.css $(DESTDIR)$(CGIT_DATA_PATH)/cgit.css
         $(INSTALL) -m 0644 cgit.png $(DESTDIR)$(CGIT_DATA_PATH)/cgit.png
 
 uninstall:
         rm -f $(CGIT_SCRIPT_PATH)/$(CGIT_SCRIPT_NAME)
         rm -f $(CGIT_DATA_PATH)/cgit.css
         rm -f $(CGIT_DATA_PATH)/cgit.png
 
 doc: man-doc html-doc pdf-doc
 
 man-doc: cgitrc.5.txt
         a2x -f manpage cgitrc.5.txt
 
 html-doc: cgitrc.5.txt
         a2x -f xhtml --stylesheet=cgit-doc.css cgitrc.5.txt
 
 pdf-doc: cgitrc.5.txt
         a2x -f pdf cgitrc.5.txt
 
 clean: clean-doc
         rm -f cgit VERSION *.o *.d
 
 clean-doc:
         rm -f cgitrc.5 cgitrc.5.html cgitrc.5.pdf cgitrc.5.xml cgitrc.5.fo
 
 get-git:
         curl $(GIT_URL) | tar -xj && rm -rf git && mv git-$(GIT_VER) git
diff --git a/cgit.c b/cgit.c
index 08cb5d2..4f68a4b 100644
--- a/cgit.c
+++ b/cgit.c
@@ -1,670 +1,675 @@
 /* cgit.c: cgi for the git scm
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "cache.h"
 #include "cmd.h"
 #include "configfile.h"
 #include "html.h"
 #include "ui-shared.h"
 #include "ui-stats.h"
 #include "scan-tree.h"
 
 const char *cgit_version = CGIT_VERSION;
 
 void add_mimetype(const char *name, const char *value)
 {
         struct string_list_item *item;
 
         item = string_list_insert(xstrdup(name), &ctx.cfg.mimetypes);
         item->util = xstrdup(value);
 }
 
 struct cgit_filter *new_filter(const char *cmd, int extra_args)
 {
         struct cgit_filter *f;
 
         if (!cmd || !cmd[0])
                 return NULL;
 
         f = xmalloc(sizeof(struct cgit_filter));
         f->cmd = xstrdup(cmd);
         f->argv = xmalloc((2 + extra_args) * sizeof(char *));
         f->argv[0] = f->cmd;
         f->argv[1] = NULL;
         return f;
 }
 
 static void process_cached_repolist(const char *path);
 
 void repo_config(struct cgit_repo *repo, const char *name, const char *value)
 {
         if (!strcmp(name, "name"))
                 repo->name = xstrdup(value);
         else if (!strcmp(name, "clone-url"))
                 repo->clone_url = xstrdup(value);
         else if (!strcmp(name, "desc"))
                 repo->desc = xstrdup(value);
         else if (!strcmp(name, "owner"))
                 repo->owner = xstrdup(value);
         else if (!strcmp(name, "defbranch"))
                 repo->defbranch = xstrdup(value);
         else if (!strcmp(name, "snapshots"))
                 repo->snapshots = ctx.cfg.snapshots & cgit_parse_snapshots_mask(value);
         else if (!strcmp(name, "enable-log-filecount"))
                 repo->enable_log_filecount = ctx.cfg.enable_log_filecount * atoi(value);
         else if (!strcmp(name, "enable-log-linecount"))
                 repo->enable_log_linecount = ctx.cfg.enable_log_linecount * atoi(value);
         else if (!strcmp(name, "max-stats"))
                 repo->max_stats = cgit_find_stats_period(value, NULL);
         else if (!strcmp(name, "module-link"))
                 repo->module_link= xstrdup(value);
         else if (!strcmp(name, "section"))
                 repo->section = xstrdup(value);
         else if (!strcmp(name, "readme") && value != NULL) {
                 if (*value == '/')
                         repo->readme = xstrdup(value);
                 else
                         repo->readme = xstrdup(fmt("%s/%s", repo->path, value));
         } else if (ctx.cfg.enable_filter_overrides) {
                 if (!strcmp(name, "about-filter"))
                         repo->about_filter = new_filter(value, 0);
                 else if (!strcmp(name, "commit-filter"))
                         repo->commit_filter = new_filter(value, 0);
                 else if (!strcmp(name, "source-filter"))
                         repo->source_filter = new_filter(value, 1);
         }
 }
 
 void config_cb(const char *name, const char *value)
 {
         if (!strcmp(name, "section") || !strcmp(name, "repo.group"))
                 ctx.cfg.section = xstrdup(value);
         else if (!strcmp(name, "repo.url"))
                 ctx.repo = cgit_add_repo(value);
         else if (ctx.repo && !strcmp(name, "repo.path"))
                 ctx.repo->path = trim_end(value, '/');
         else if (ctx.repo && !prefixcmp(name, "repo."))
                 repo_config(ctx.repo, name + 5, value);
         else if (!strcmp(name, "root-title"))
                 ctx.cfg.root_title = xstrdup(value);
         else if (!strcmp(name, "root-desc"))
                 ctx.cfg.root_desc = xstrdup(value);
         else if (!strcmp(name, "root-readme"))
                 ctx.cfg.root_readme = xstrdup(value);
         else if (!strcmp(name, "css"))
                 ctx.cfg.css = xstrdup(value);
         else if (!strcmp(name, "favicon"))
                 ctx.cfg.favicon = xstrdup(value);
         else if (!strcmp(name, "footer"))
                 ctx.cfg.footer = xstrdup(value);
         else if (!strcmp(name, "head-include"))
                 ctx.cfg.head_include = xstrdup(value);
         else if (!strcmp(name, "header"))
                 ctx.cfg.header = xstrdup(value);
         else if (!strcmp(name, "logo"))
                 ctx.cfg.logo = xstrdup(value);
         else if (!strcmp(name, "index-header"))
                 ctx.cfg.index_header = xstrdup(value);
         else if (!strcmp(name, "index-info"))
                 ctx.cfg.index_info = xstrdup(value);
         else if (!strcmp(name, "logo-link"))
                 ctx.cfg.logo_link = xstrdup(value);
         else if (!strcmp(name, "module-link"))
                 ctx.cfg.module_link = xstrdup(value);
         else if (!strcmp(name, "virtual-root")) {
                 ctx.cfg.virtual_root = trim_end(value, '/');
                 if (!ctx.cfg.virtual_root && (!strcmp(value, "/")))
                         ctx.cfg.virtual_root = "";
         } else if (!strcmp(name, "nocache"))
                 ctx.cfg.nocache = atoi(value);
         else if (!strcmp(name, "noplainemail"))
                 ctx.cfg.noplainemail = atoi(value);
         else if (!strcmp(name, "noheader"))
                 ctx.cfg.noheader = atoi(value);
         else if (!strcmp(name, "snapshots"))
                 ctx.cfg.snapshots = cgit_parse_snapshots_mask(value);
         else if (!strcmp(name, "enable-filter-overrides"))
                 ctx.cfg.enable_filter_overrides = atoi(value);
         else if (!strcmp(name, "enable-index-links"))
                 ctx.cfg.enable_index_links = atoi(value);
         else if (!strcmp(name, "enable-log-filecount"))
                 ctx.cfg.enable_log_filecount = atoi(value);
         else if (!strcmp(name, "enable-log-linecount"))
                 ctx.cfg.enable_log_linecount = atoi(value);
         else if (!strcmp(name, "enable-tree-linenumbers"))
                 ctx.cfg.enable_tree_linenumbers = atoi(value);
         else if (!strcmp(name, "max-stats"))
                 ctx.cfg.max_stats = cgit_find_stats_period(value, NULL);
         else if (!strcmp(name, "cache-size"))
                 ctx.cfg.cache_size = atoi(value);
         else if (!strcmp(name, "cache-root"))
                 ctx.cfg.cache_root = xstrdup(value);
         else if (!strcmp(name, "cache-root-ttl"))
                 ctx.cfg.cache_root_ttl = atoi(value);
         else if (!strcmp(name, "cache-repo-ttl"))
                 ctx.cfg.cache_repo_ttl = atoi(value);
         else if (!strcmp(name, "cache-scanrc-ttl"))
                 ctx.cfg.cache_scanrc_ttl = atoi(value);
         else if (!strcmp(name, "cache-static-ttl"))
                 ctx.cfg.cache_static_ttl = atoi(value);
         else if (!strcmp(name, "cache-dynamic-ttl"))
                 ctx.cfg.cache_dynamic_ttl = atoi(value);
         else if (!strcmp(name, "about-filter"))
                 ctx.cfg.about_filter = new_filter(value, 0);
         else if (!strcmp(name, "commit-filter"))
                 ctx.cfg.commit_filter = new_filter(value, 0);
         else if (!strcmp(name, "embedded"))
                 ctx.cfg.embedded = atoi(value);
         else if (!strcmp(name, "max-message-length"))
                 ctx.cfg.max_msg_len = atoi(value);
         else if (!strcmp(name, "max-repodesc-length"))
                 ctx.cfg.max_repodesc_len = atoi(value);
         else if (!strcmp(name, "max-blob-size"))
                 ctx.cfg.max_blob_size = atoi(value);
         else if (!strcmp(name, "max-repo-count"))
                 ctx.cfg.max_repo_count = atoi(value);
         else if (!strcmp(name, "max-commit-count"))
                 ctx.cfg.max_commit_count = atoi(value);
         else if (!strcmp(name, "scan-path"))
                 if (!ctx.cfg.nocache && ctx.cfg.cache_size)
                         process_cached_repolist(value);
                 else
                         scan_tree(value, repo_config);
         else if (!strcmp(name, "source-filter"))
                 ctx.cfg.source_filter = new_filter(value, 1);
         else if (!strcmp(name, "summary-log"))
                 ctx.cfg.summary_log = atoi(value);
         else if (!strcmp(name, "summary-branches"))
                 ctx.cfg.summary_branches = atoi(value);
         else if (!strcmp(name, "summary-tags"))
                 ctx.cfg.summary_tags = atoi(value);
+        else if (!strcmp(name, "side-by-side-diffs"))
+                ctx.cfg.ssdiff = atoi(value);
         else if (!strcmp(name, "agefile"))
                 ctx.cfg.agefile = xstrdup(value);
         else if (!strcmp(name, "renamelimit"))
                 ctx.cfg.renamelimit = atoi(value);
         else if (!strcmp(name, "robots"))
                 ctx.cfg.robots = xstrdup(value);
         else if (!strcmp(name, "clone-prefix"))
                 ctx.cfg.clone_prefix = xstrdup(value);
         else if (!strcmp(name, "local-time"))
                 ctx.cfg.local_time = atoi(value);
         else if (!prefixcmp(name, "mimetype."))
                 add_mimetype(name + 9, value);
         else if (!strcmp(name, "include"))
                 parse_configfile(value, config_cb);
 }
 
 static void querystring_cb(const char *name, const char *value)
 {
         if (!value)
                 value = "";
 
         if (!strcmp(name,"r")) {
                 ctx.qry.repo = xstrdup(value);
                 ctx.repo = cgit_get_repoinfo(value);
         } else if (!strcmp(name, "p")) {
                 ctx.qry.page = xstrdup(value);
         } else if (!strcmp(name, "url")) {
                 if (*value == '/')
                         value++;
                 ctx.qry.url = xstrdup(value);
                 cgit_parse_url(value);
         } else if (!strcmp(name, "qt")) {
                 ctx.qry.grep = xstrdup(value);
         } else if (!strcmp(name, "q")) {
                 ctx.qry.search = xstrdup(value);
         } else if (!strcmp(name, "h")) {
                 ctx.qry.head = xstrdup(value);
                 ctx.qry.has_symref = 1;
         } else if (!strcmp(name, "id")) {
                 ctx.qry.sha1 = xstrdup(value);
                 ctx.qry.has_sha1 = 1;
         } else if (!strcmp(name, "id2")) {
                 ctx.qry.sha2 = xstrdup(value);
                 ctx.qry.has_sha1 = 1;
         } else if (!strcmp(name, "ofs")) {
                 ctx.qry.ofs = atoi(value);
         } else if (!strcmp(name, "path")) {
                 ctx.qry.path = trim_end(value, '/');
         } else if (!strcmp(name, "name")) {
                 ctx.qry.name = xstrdup(value);
         } else if (!strcmp(name, "mimetype")) {
                 ctx.qry.mimetype = xstrdup(value);
         } else if (!strcmp(name, "s")){
                 ctx.qry.sort = xstrdup(value);
         } else if (!strcmp(name, "showmsg")) {
                 ctx.qry.showmsg = atoi(value);
         } else if (!strcmp(name, "period")) {
                 ctx.qry.period = xstrdup(value);
+        } else if (!strcmp(name, "ss")) {
+                ctx.qry.ssdiff = atoi(value);
         }
 }
 
 char *xstrdupn(const char *str)
 {
         return (str ? xstrdup(str) : NULL);
 }
 
 static void prepare_context(struct cgit_context *ctx)
 {
         memset(ctx, 0, sizeof(ctx));
         ctx->cfg.agefile = "info/web/last-modified";
         ctx->cfg.nocache = 0;
         ctx->cfg.cache_size = 0;
         ctx->cfg.cache_dynamic_ttl = 5;
         ctx->cfg.cache_max_create_time = 5;
         ctx->cfg.cache_repo_ttl = 5;
         ctx->cfg.cache_root = CGIT_CACHE_ROOT;
         ctx->cfg.cache_root_ttl = 5;
         ctx->cfg.cache_scanrc_ttl = 15;
         ctx->cfg.cache_static_ttl = -1;
         ctx->cfg.css = "/cgit.css";
         ctx->cfg.logo = "/cgit.png";
         ctx->cfg.local_time = 0;
         ctx->cfg.enable_tree_linenumbers = 1;
         ctx->cfg.max_repo_count = 50;
         ctx->cfg.max_commit_count = 50;
         ctx->cfg.max_lock_attempts = 5;
         ctx->cfg.max_msg_len = 80;
         ctx->cfg.max_repodesc_len = 80;
         ctx->cfg.max_blob_size = 0;
         ctx->cfg.max_stats = 0;
         ctx->cfg.module_link = "./?repo=%s&page=commit&id=%s";
         ctx->cfg.renamelimit = -1;
         ctx->cfg.robots = "index, nofollow";
         ctx->cfg.root_title = "Git repository browser";
         ctx->cfg.root_desc = "a fast webinterface for the git dscm";
         ctx->cfg.script_name = CGIT_SCRIPT_NAME;
         ctx->cfg.section = "";
         ctx->cfg.summary_branches = 10;
         ctx->cfg.summary_log = 10;
         ctx->cfg.summary_tags = 10;
+        ctx->cfg.ssdiff = 0;
         ctx->env.cgit_config = xstrdupn(getenv("CGIT_CONFIG"));
         ctx->env.http_host = xstrdupn(getenv("HTTP_HOST"));
         ctx->env.https = xstrdupn(getenv("HTTPS"));
         ctx->env.no_http = xstrdupn(getenv("NO_HTTP"));
         ctx->env.path_info = xstrdupn(getenv("PATH_INFO"));
         ctx->env.query_string = xstrdupn(getenv("QUERY_STRING"));
         ctx->env.request_method = xstrdupn(getenv("REQUEST_METHOD"));
         ctx->env.script_name = xstrdupn(getenv("SCRIPT_NAME"));
         ctx->env.server_name = xstrdupn(getenv("SERVER_NAME"));
         ctx->env.server_port = xstrdupn(getenv("SERVER_PORT"));
         ctx->page.mimetype = "text/html";
         ctx->page.charset = PAGE_ENCODING;
         ctx->page.filename = NULL;
         ctx->page.size = 0;
         ctx->page.modified = time(NULL);
         ctx->page.expires = ctx->page.modified;
         ctx->page.etag = NULL;
         memset(&ctx->cfg.mimetypes, 0, sizeof(struct string_list));
         if (ctx->env.script_name)
                 ctx->cfg.script_name = ctx->env.script_name;
         if (ctx->env.query_string)
                 ctx->qry.raw = ctx->env.query_string;
         if (!ctx->env.cgit_config)
                 ctx->env.cgit_config = CGIT_CONFIG;
 }
 
 struct refmatch {
         char *req_ref;
         char *first_ref;
         int match;
 };
 
 int find_current_ref(const char *refname, const unsigned char *sha1,
                      int flags, void *cb_data)
 {
         struct refmatch *info;
 
         info = (struct refmatch *)cb_data;
         if (!strcmp(refname, info->req_ref))
                 info->match = 1;
         if (!info->first_ref)
                 info->first_ref = xstrdup(refname);
         return info->match;
 }
 
 char *find_default_branch(struct cgit_repo *repo)
 {
         struct refmatch info;
         char *ref;
 
         info.req_ref = repo->defbranch;
         info.first_ref = NULL;
         info.match = 0;
         for_each_branch_ref(find_current_ref, &info);
         if (info.match)
                 ref = info.req_ref;
         else
                 ref = info.first_ref;
         if (ref)
                 ref = xstrdup(ref);
         return ref;
 }
 
 static int prepare_repo_cmd(struct cgit_context *ctx)
 {
         char *tmp;
         unsigned char sha1[20];
         int nongit = 0;
 
         setenv("GIT_DIR", ctx->repo->path, 1);
         setup_git_directory_gently(&nongit);
         if (nongit) {
                 ctx->page.title = fmt("%s - %s", ctx->cfg.root_title,
                                       "config error");
                 tmp = fmt("Not a git repository: '%s'", ctx->repo->path);
                 ctx->repo = NULL;
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error(tmp);
                 cgit_print_docend();
                 return 1;
         }
         ctx->page.title = fmt("%s - %s", ctx->repo->name, ctx->repo->desc);
 
         if (!ctx->qry.head) {
                 ctx->qry.nohead = 1;
                 ctx->qry.head = find_default_branch(ctx->repo);
                 ctx->repo->defbranch = ctx->qry.head;
         }
 
         if (!ctx->qry.head) {
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error("Repository seems to be empty");
                 cgit_print_docend();
                 return 1;
         }
 
         if (get_sha1(ctx->qry.head, sha1)) {
                 tmp = xstrdup(ctx->qry.head);
                 ctx->qry.head = ctx->repo->defbranch;
                 ctx->page.status = 404;
                 ctx->page.statusmsg = "not found";
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error(fmt("Invalid branch: %s", tmp));
                 cgit_print_docend();
                 return 1;
         }
         return 0;
 }
 
 static void process_request(void *cbdata)
 {
         struct cgit_context *ctx = cbdata;
         struct cgit_cmd *cmd;
 
         cmd = cgit_get_cmd(ctx);
         if (!cmd) {
                 ctx->page.title = "cgit error";
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error("Invalid request");
                 cgit_print_docend();
                 return;
         }
 
         if (cmd->want_repo && !ctx->repo) {
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error(fmt("No repository selected"));
                 cgit_print_docend();
                 return;
         }
 
         if (ctx->repo && prepare_repo_cmd(ctx))
                 return;
 
         if (cmd->want_layout) {
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
         }
 
         cmd->fn(ctx);
 
         if (cmd->want_layout)
                 cgit_print_docend();
 }
 
 int cmp_repos(const void *a, const void *b)
 {
         const struct cgit_repo *ra = a, *rb = b;
         return strcmp(ra->url, rb->url);
 }
 
 char *build_snapshot_setting(int bitmap)
 {
         const struct cgit_snapshot_format *f;
         char *result = xstrdup("");
         char *tmp;
         int len;
 
         for (f = cgit_snapshot_formats; f->suffix; f++) {
                 if (f->bit & bitmap) {
                         tmp = result;
                         result = xstrdup(fmt("%s%s ", tmp, f->suffix));
                         free(tmp);
                 }
         }
         len = strlen(result);
         if (len)
                 result[len - 1] = '\0';
         return result;
 }
 
 char *get_first_line(char *txt)
 {
         char *t = xstrdup(txt);
         char *p = strchr(t, '\n');
         if (p)
                 *p = '\0';
         return t;
 }
 
 void print_repo(FILE *f, struct cgit_repo *repo)
 {
         fprintf(f, "repo.url=%s\n", repo->url);
         fprintf(f, "repo.name=%s\n", repo->name);
         fprintf(f, "repo.path=%s\n", repo->path);
         if (repo->owner)
                 fprintf(f, "repo.owner=%s\n", repo->owner);
         if (repo->desc) {
                 char *tmp = get_first_line(repo->desc);
                 fprintf(f, "repo.desc=%s\n", tmp);
                 free(tmp);
         }
         if (repo->readme)
                 fprintf(f, "repo.readme=%s\n", repo->readme);
         if (repo->defbranch)
                 fprintf(f, "repo.defbranch=%s\n", repo->defbranch);
         if (repo->module_link)
                 fprintf(f, "repo.module-link=%s\n", repo->module_link);
         if (repo->section)
                 fprintf(f, "repo.section=%s\n", repo->section);
         if (repo->clone_url)
                 fprintf(f, "repo.clone-url=%s\n", repo->clone_url);
         fprintf(f, "repo.enable-log-filecount=%d\n",
                 repo->enable_log_filecount);
         fprintf(f, "repo.enable-log-linecount=%d\n",
                 repo->enable_log_linecount);
         if (repo->about_filter && repo->about_filter != ctx.cfg.about_filter)
                 fprintf(f, "repo.about-filter=%s\n", repo->about_filter->cmd);
         if (repo->commit_filter && repo->commit_filter != ctx.cfg.commit_filter)
                 fprintf(f, "repo.commit-filter=%s\n", repo->commit_filter->cmd);
         if (repo->source_filter && repo->source_filter != ctx.cfg.source_filter)
                 fprintf(f, "repo.source-filter=%s\n", repo->source_filter->cmd);
         if (repo->snapshots != ctx.cfg.snapshots) {
                 char *tmp = build_snapshot_setting(repo->snapshots);
                 fprintf(f, "repo.snapshots=%s\n", tmp);
                 free(tmp);
         }
         if (repo->max_stats != ctx.cfg.max_stats)
                 fprintf(f, "repo.max-stats=%s\n",
                         cgit_find_stats_periodname(repo->max_stats));
         fprintf(f, "\n");
 }
 
 void print_repolist(FILE *f, struct cgit_repolist *list, int start)
 {
         int i;
 
         for(i = start; i < list->count; i++)
                 print_repo(f, &list->repos[i]);
 }
 
 /* Scan 'path' for git repositories, save the resulting repolist in 'cached_rc'
  * and return 0 on success.
  */
 static int generate_cached_repolist(const char *path, const char *cached_rc)
 {
         char *locked_rc;
         int idx;
         FILE *f;
 
         locked_rc = xstrdup(fmt("%s.lock", cached_rc));
         f = fopen(locked_rc, "wx");
         if (!f) {
                 /* Inform about the error unless the lockfile already existed,
                  * since that only means we've got concurrent requests.
                  */
                 if (errno != EEXIST)
                         fprintf(stderr, "[cgit] Error opening %s: %s (%d)\n",
                                 locked_rc, strerror(errno), errno);
                 return errno;
         }
         idx = cgit_repolist.count;
         scan_tree(path, repo_config);
         print_repolist(f, &cgit_repolist, idx);
         if (rename(locked_rc, cached_rc))
                 fprintf(stderr, "[cgit] Error renaming %s to %s: %s (%d)\n",
                         locked_rc, cached_rc, strerror(errno), errno);
         fclose(f);
         return 0;
 }
 
 static void process_cached_repolist(const char *path)
 {
         struct stat st;
         char *cached_rc;
         time_t age;
 
         cached_rc = xstrdup(fmt("%s/rc-%8x", ctx.cfg.cache_root,
                 hash_str(path)));
 
         if (stat(cached_rc, &st)) {
                 /* Nothing is cached, we need to scan without forking. And
                  * if we fail to generate a cached repolist, we need to
                  * invoke scan_tree manually.
                  */
                 if (generate_cached_repolist(path, cached_rc))
                         scan_tree(path, repo_config);
                 return;
         }
 
         parse_configfile(cached_rc, config_cb);
 
         /* If the cached configfile hasn't expired, lets exit now */
         age = time(NULL) - st.st_mtime;
         if (age <= (ctx.cfg.cache_scanrc_ttl * 60))
                 return;
 
         /* The cached repolist has been parsed, but it was old. So lets
          * rescan the specified path and generate a new cached repolist
          * in a child-process to avoid latency for the current request.
          */
         if (fork())
                 return;
 
         exit(generate_cached_repolist(path, cached_rc));
 }
 
 static void cgit_parse_args(int argc, const char **argv)
 {
         int i;
         int scan = 0;
 
         for (i = 1; i < argc; i++) {
                 if (!strncmp(argv[i], "--cache=", 8)) {
                         ctx.cfg.cache_root = xstrdup(argv[i]+8);
                 }
                 if (!strcmp(argv[i], "--nocache")) {
                         ctx.cfg.nocache = 1;
                 }
                 if (!strcmp(argv[i], "--nohttp")) {
                         ctx.env.no_http = "1";
                 }
                 if (!strncmp(argv[i], "--query=", 8)) {
                         ctx.qry.raw = xstrdup(argv[i]+8);
                 }
                 if (!strncmp(argv[i], "--repo=", 7)) {
                         ctx.qry.repo = xstrdup(argv[i]+7);
                 }
                 if (!strncmp(argv[i], "--page=", 7)) {
                         ctx.qry.page = xstrdup(argv[i]+7);
                 }
                 if (!strncmp(argv[i], "--head=", 7)) {
                         ctx.qry.head = xstrdup(argv[i]+7);
                         ctx.qry.has_symref = 1;
                 }
                 if (!strncmp(argv[i], "--sha1=", 7)) {
                         ctx.qry.sha1 = xstrdup(argv[i]+7);
                         ctx.qry.has_sha1 = 1;
                 }
                 if (!strncmp(argv[i], "--ofs=", 6)) {
                         ctx.qry.ofs = atoi(argv[i]+6);
                 }
                 if (!strncmp(argv[i], "--scan-tree=", 12) ||
                     !strncmp(argv[i], "--scan-path=", 12)) {
                         /* HACK: the global snapshot bitmask defines the
                          * set of allowed snapshot formats, but the config
                          * file hasn't been parsed yet so the mask is
                          * currently 0. By setting all bits high before
                          * scanning we make sure that any in-repo cgitrc
                          * snapshot setting is respected by scan_tree().
                          * BTW: we assume that there'll never be more than
                          * 255 different snapshot formats supported by cgit...
                          */
                         ctx.cfg.snapshots = 0xFF;
                         scan++;
                         scan_tree(argv[i] + 12, repo_config);
                 }
         }
         if (scan) {
                 qsort(cgit_repolist.repos, cgit_repolist.count,
                         sizeof(struct cgit_repo), cmp_repos);
                 print_repolist(stdout, &cgit_repolist, 0);
                 exit(0);
         }
 }
 
 static int calc_ttl()
 {
         if (!ctx.repo)
                 return ctx.cfg.cache_root_ttl;
 
         if (!ctx.qry.page)
                 return ctx.cfg.cache_repo_ttl;
 
         if (ctx.qry.has_symref)
                 return ctx.cfg.cache_dynamic_ttl;
 
         if (ctx.qry.has_sha1)
                 return ctx.cfg.cache_static_ttl;
 
         return ctx.cfg.cache_repo_ttl;
 }
 
 int main(int argc, const char **argv)
diff --git a/cgit.css b/cgit.css
index ef7d3c1..0cb894a 100644
--- a/cgit.css
+++ b/cgit.css
@@ -225,384 +225,483 @@ a.ls-blob, a.ls-dir, a.ls-mod {
         font-family: monospace;
 }
 
 td.ls-size {
         text-align: right;
         font-family: monospace;
         width: 10em;
 }
 
 td.ls-mode {
         font-family: monospace;
         width: 10em;
 }
 
 table.blob {
         margin-top: 0.5em;
         border-top: solid 1px black;
 }
 
 table.blob td.lines {
         margin: 0; padding: 0 0 0 0.5em;
         vertical-align: top;
         color: black;
 }
 
 table.blob td.linenumbers {
         margin: 0; padding: 0 0.5em 0 0.5em;
         vertical-align: top;
         text-align: right;
         border-right: 1px solid gray;
 }
 
 table.blob pre {
         padding: 0; margin: 0;
 }
 
 table.blob a.no {
         color: gray;
         text-align: right;
         text-decoration: none;
 }
 
 table.blob a.no a:hover {
         color: black;
 }
 
 table.bin-blob {
         margin-top: 0.5em;
         border: solid 1px black;
 }
 
 table.bin-blob th {
         font-family: monospace;
         white-space: pre;
         border: solid 1px #777;
         padding: 0.5em 1em;
 }
 
 table.bin-blob td {
         font-family: monospace;
         white-space: pre;
         border-left: solid 1px #777;
         padding: 0em 1em;
 }
 
 table.nowrap td {
         white-space: nowrap;
 }
 
 table.commit-info {
         border-collapse: collapse;
         margin-top: 1.5em;
 }
 
 table.commit-info th {
         text-align: left;
         font-weight: normal;
         padding: 0.1em 1em 0.1em 0.1em;
         vertical-align: top;
 }
 
 table.commit-info td {
         font-weight: normal;
         padding: 0.1em 1em 0.1em 0.1em;
 }
 
 div.commit-subject {
         font-weight: bold;
         font-size: 125%;
         margin: 1.5em 0em 0.5em 0em;
         padding: 0em;
 }
 
 div.commit-msg {
         white-space: pre;
         font-family: monospace;
 }
 
 div.diffstat-header {
         font-weight: bold;
         padding-top: 1.5em;
 }
 
 table.diffstat {
         border-collapse: collapse;
         border: solid 1px #aaa;
         background-color: #eee;
 }
 
 table.diffstat th {
         font-weight: normal;
         text-align: left;
         text-decoration: underline;
         padding: 0.1em 1em 0.1em 0.1em;
         font-size: 100%;
 }
 
 table.diffstat td {
         padding: 0.2em 0.2em 0.1em 0.1em;
         font-size: 100%;
         border: none;
 }
 
 table.diffstat td.mode {
         white-space: nowrap;
 }
 
 table.diffstat td span.modechange {
         padding-left: 1em;
         color: red;
 }
 
 table.diffstat td.add a {
         color: green;
 }
 
 table.diffstat td.del a {
         color: red;
 }
 
 table.diffstat td.upd a {
         color: blue;
 }
 
 table.diffstat td.graph {
         width: 500px;
         vertical-align: middle;
 }
 
 table.diffstat td.graph table {
         border: none;
 }
 
 table.diffstat td.graph td {
         padding: 0px;
         border: 0px;
         height: 7pt;
 }
 
 table.diffstat td.graph td.add {
         background-color: #5c5;
 }
 
 table.diffstat td.graph td.rem {
         background-color: #c55;
 }
 
 div.diffstat-summary {
         color: #888;
         padding-top: 0.5em;
 }
 
 table.diff {
         width: 100%;
 }
 
 table.diff td {
         font-family: monospace;
         white-space: pre;
 }
 
 table.diff td div.head {
         font-weight: bold;
         margin-top: 1em;
         color: black;
 }
 
 table.diff td div.hunk {
         color: #009;
 }
 
 table.diff td div.add {
         color: green;
 }
 
 table.diff td div.del {
         color: red;
 }
 
 .sha1 {
         font-family: monospace;
         font-size: 90%;
 }
 
 .left {
         text-align: left;
 }
 
 .right {
         text-align: right;
 }
 
 table.list td.reposection {
         font-style: italic;
         color: #888;
 }
 
 a.button {
         font-size: 80%;
         padding: 0em 0.5em;
 }
 
 a.primary {
         font-size: 100%;
 }
 
 a.secondary {
         font-size: 90%;
 }
 
 td.toplevel-repo {
 
 }
 
 table.list td.sublevel-repo {
         padding-left: 1.5em;
 }
 
 div.pager {
         text-align: center;
         margin: 1em 0em 0em 0em;
 }
 
 div.pager a {
         color: #777;
         margin: 0em 0.5em;
 }
 
 span.age-mins {
         font-weight: bold;
         color: #080;
 }
 
 span.age-hours {
         color: #080;
 }
 
 span.age-days {
         color: #040;
 }
 
 span.age-weeks {
         color: #444;
 }
 
 span.age-months {
         color: #888;
 }
 
 span.age-years {
         color: #bbb;
 }
 div.footer {
         margin-top: 0.5em;
         text-align: center;
         font-size: 80%;
         color: #ccc;
 }
 a.branch-deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #88ff88;
         border: solid 1px #007700;
 }
 a.tag-deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #ffff88;
         border: solid 1px #777700;
 }
 a.remote-deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #ccccff;
         border: solid 1px #000077;
 }
 a.deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #ff8888;
         border: solid 1px #770000;
 }
 
 div.commit-subject a {
         margin-left: 1em;
         font-size: 75%;
 }
 
 table.stats {
         border: solid 1px black;
         border-collapse: collapse;
 }
 
 table.stats th {
         text-align: left;
         padding: 1px 0.5em;
         background-color: #eee;
         border: solid 1px black;
 }
 
 table.stats td {
         text-align: right;
         padding: 1px 0.5em;
         border: solid 1px black;
 }
 
 table.stats td.total {
         font-weight: bold;
         text-align: left;
 }
 
 table.stats td.sum {
         color: #c00;
         font-weight: bold;
         /*background-color: #eee; */
 }
 
 table.stats td.left {
         text-align: left;
 }
 
 table.vgraph {
         border-collapse: separate;
         border: solid 1px black;
         height: 200px;
 }
 
 table.vgraph th {
         background-color: #eee;
         font-weight: bold;
         border: solid 1px white;
         padding: 1px 0.5em;
 }
 
 table.vgraph td {
         vertical-align: bottom;
         padding: 0px 10px;
 }
 
 table.vgraph div.bar {
         background-color: #eee;
 }
 
 table.hgraph {
         border: solid 1px black;
         width: 800px;
 }
 
 table.hgraph th {
         background-color: #eee;
         font-weight: bold;
         border: solid 1px black;
         padding: 1px 0.5em;
 }
 
 table.hgraph td {
         vertical-align: center;
         padding: 2px 2px;
 }
 
 table.hgraph div.bar {
         background-color: #eee;
         height: 1em;
 }
+
+table.ssdiff {
+        width: 100%;
+}
+
+table.ssdiff td {
+        font-size: 75%;
+        font-family: monospace;
+        white-space: pre;
+        padding: 1px 4px 1px 4px;
+        border-left: solid 1px #aaa;
+        border-right: solid 1px #aaa;
+}
+
+table.ssdiff td.add {
+        color: black;
+        background: #cfc;
+        min-width: 50%;
+}
+
+table.ssdiff td.add_dark {
+        color: black;
+        background: #aca;
+        min-width: 50%;
+}
+
+table.ssdiff span.add {
+        background: #cfc;
+        font-weight: bold;
+}
+
+table.ssdiff td.del {
+        color: black;
+        background: #fcc;
+        min-width: 50%;
+}
+
+table.ssdiff td.del_dark {
+        color: black;
+        background: #caa;
+        min-width: 50%;
+}
+
+table.ssdiff span.del {
+        background: #fcc;
+        font-weight: bold;
+}
+
+table.ssdiff td.changed {
+        color: black;
+        background: #ffc;
+        min-width: 50%;
+}
+
+table.ssdiff td.changed_dark {
+        color: black;
+        background: #cca;
+        min-width: 50%;
+}
+
+table.ssdiff td.lineno {
+        color: black;
+        background: #eee;
+        text-align: right;
+        width: 3em;
+        min-width: 3em;
+}
+
+table.ssdiff td.hunk {
+        color: #black;
+        background: #ccf;
+        border-top: solid 1px #aaa;
+        border-bottom: solid 1px #aaa;
+}
+
+table.ssdiff td.head {
+        border-top: solid 1px #aaa;
+        border-bottom: solid 1px #aaa;
+}
+
+table.ssdiff td.head div.head {
+        font-weight: bold;
+        color: black;
+}
+
+table.ssdiff td.foot {
+        border-top: solid 1px #aaa;
+        border-left: none;
+        border-right: none;
+        border-bottom: none;
+}
+
+table.ssdiff td.space {
+        border: none;
+}
+
+table.ssdiff td.space div {
+        min-height: 3em;
+}
\ No newline at end of file
diff --git a/cgit.h b/cgit.h
index 39853df..5941ec0 100644
--- a/cgit.h
+++ b/cgit.h
@@ -1,295 +1,297 @@
 #ifndef CGIT_H
 #define CGIT_H
 
 
 #include <git-compat-util.h>
 #include <cache.h>
 #include <grep.h>
 #include <object.h>
 #include <tree.h>
 #include <commit.h>
 #include <tag.h>
 #include <diff.h>
 #include <diffcore.h>
 #include <refs.h>
 #include <revision.h>
 #include <log-tree.h>
 #include <archive.h>
 #include <string-list.h>
 #include <xdiff-interface.h>
 #include <xdiff/xdiff.h>
 #include <utf8.h>
 
 
 /*
  * Dateformats used on misc. pages
  */
 #define FMT_LONGDATE "%Y-%m-%d %H:%M:%S (%Z)"
 #define FMT_SHORTDATE "%Y-%m-%d"
 #define FMT_ATOMDATE "%Y-%m-%dT%H:%M:%SZ"
 
 
 /*
  * Limits used for relative dates
  */
 #define TM_MIN    60
 #define TM_HOUR  (TM_MIN * 60)
 #define TM_DAY   (TM_HOUR * 24)
 #define TM_WEEK  (TM_DAY * 7)
 #define TM_YEAR  (TM_DAY * 365)
 #define TM_MONTH (TM_YEAR / 12.0)
 
 
 /*
  * Default encoding
  */
 #define PAGE_ENCODING "UTF-8"
 
 typedef void (*configfn)(const char *name, const char *value);
 typedef void (*filepair_fn)(struct diff_filepair *pair);
 typedef void (*linediff_fn)(char *line, int len);
 
 struct cgit_filter {
         char *cmd;
         char **argv;
         int old_stdout;
         int pipe_fh[2];
         int pid;
         int exitstatus;
 };
 
 struct cgit_repo {
         char *url;
         char *name;
         char *path;
         char *desc;
         char *owner;
         char *defbranch;
         char *module_link;
         char *readme;
         char *section;
         char *clone_url;
         int snapshots;
         int enable_log_filecount;
         int enable_log_linecount;
         int max_stats;
         time_t mtime;
         struct cgit_filter *about_filter;
         struct cgit_filter *commit_filter;
         struct cgit_filter *source_filter;
 };
 
 typedef void (*repo_config_fn)(struct cgit_repo *repo, const char *name,
               const char *value);
 
 struct cgit_repolist {
         int length;
         int count;
         struct cgit_repo *repos;
 };
 
 struct commitinfo {
         struct commit *commit;
         char *author;
         char *author_email;
         unsigned long author_date;
         char *committer;
         char *committer_email;
         unsigned long committer_date;
         char *subject;
         char *msg;
         char *msg_encoding;
 };
 
 struct taginfo {
         char *tagger;
         char *tagger_email;
         unsigned long tagger_date;
         char *msg;
 };
 
 struct refinfo {
         const char *refname;
         struct object *object;
         union {
                 struct taginfo *tag;
                 struct commitinfo *commit;
         };
 };
 
 struct reflist {
         struct refinfo **refs;
         int alloc;
         int count;
 };
 
 struct cgit_query {
         int has_symref;
         int has_sha1;
         char *raw;
         char *repo;
         char *page;
         char *search;
         char *grep;
         char *head;
         char *sha1;
         char *sha2;
         char *path;
         char *name;
         char *mimetype;
         char *url;
         char *period;
         int   ofs;
         int nohead;
         char *sort;
         int showmsg;
+        int ssdiff;
 };
 
 struct cgit_config {
         char *agefile;
         char *cache_root;
         char *clone_prefix;
         char *css;
         char *favicon;
         char *footer;
         char *head_include;
         char *header;
         char *index_header;
         char *index_info;
         char *logo;
         char *logo_link;
         char *module_link;
         char *robots;
         char *root_title;
         char *root_desc;
         char *root_readme;
         char *script_name;
         char *section;
         char *virtual_root;
         int cache_size;
         int cache_dynamic_ttl;
         int cache_max_create_time;
         int cache_repo_ttl;
         int cache_root_ttl;
         int cache_scanrc_ttl;
         int cache_static_ttl;
         int embedded;
         int enable_filter_overrides;
         int enable_index_links;
         int enable_log_filecount;
         int enable_log_linecount;
         int enable_tree_linenumbers;
         int local_time;
         int max_repo_count;
         int max_commit_count;
         int max_lock_attempts;
         int max_msg_len;
         int max_repodesc_len;
         int max_blob_size;
         int max_stats;
         int nocache;
         int noplainemail;
         int noheader;
         int renamelimit;
         int snapshots;
         int summary_branches;
         int summary_log;
         int summary_tags;
+        int ssdiff;
         struct string_list mimetypes;
         struct cgit_filter *about_filter;
         struct cgit_filter *commit_filter;
         struct cgit_filter *source_filter;
 };
 
 struct cgit_page {
         time_t modified;
         time_t expires;
         size_t size;
         char *mimetype;
         char *charset;
         char *filename;
         char *etag;
         char *title;
         int status;
         char *statusmsg;
 };
 
 struct cgit_environment {
         char *cgit_config;
         char *http_host;
         char *https;
         char *no_http;
         char *path_info;
         char *query_string;
         char *request_method;
         char *script_name;
         char *server_name;
         char *server_port;
 };
 
 struct cgit_context {
         struct cgit_environment env;
         struct cgit_query qry;
         struct cgit_config cfg;
         struct cgit_repo *repo;
         struct cgit_page page;
 };
 
 struct cgit_snapshot_format {
         const char *suffix;
         const char *mimetype;
         write_archive_fn_t write_func;
         int bit;
 };
 
 extern const char *cgit_version;
 
 extern struct cgit_repolist cgit_repolist;
 extern struct cgit_context ctx;
 extern const struct cgit_snapshot_format cgit_snapshot_formats[];
 
 extern struct cgit_repo *cgit_add_repo(const char *url);
 extern struct cgit_repo *cgit_get_repoinfo(const char *url);
 extern void cgit_repo_config_cb(const char *name, const char *value);
 
 extern int chk_zero(int result, char *msg);
 extern int chk_positive(int result, char *msg);
 extern int chk_non_negative(int result, char *msg);
 
 extern char *trim_end(const char *str, char c);
 extern char *strlpart(char *txt, int maxlen);
 extern char *strrpart(char *txt, int maxlen);
 
 extern void cgit_add_ref(struct reflist *list, struct refinfo *ref);
 extern int cgit_refs_cb(const char *refname, const unsigned char *sha1,
                         int flags, void *cb_data);
 
 extern void *cgit_free_commitinfo(struct commitinfo *info);
 
 extern int cgit_diff_files(const unsigned char *old_sha1,
                            const unsigned char *new_sha1,
                            unsigned long *old_size, unsigned long *new_size,
                            int *binary, linediff_fn fn);
 
 extern void cgit_diff_tree(const unsigned char *old_sha1,
                            const unsigned char *new_sha1,
                            filepair_fn fn, const char *prefix);
 
 extern void cgit_diff_commit(struct commit *commit, filepair_fn fn);
 
 extern char *fmt(const char *format,...);
 
 extern struct commitinfo *cgit_parse_commit(struct commit *commit);
 extern struct taginfo *cgit_parse_tag(struct tag *tag);
 extern void cgit_parse_url(const char *url);
 
 extern const char *cgit_repobasename(const char *reponame);
 
 extern int cgit_parse_snapshots_mask(const char *str);
 
 extern int cgit_open_filter(struct cgit_filter *filter);
 extern int cgit_close_filter(struct cgit_filter *filter);
 
 extern int readfile(const char *path, char **buf, size_t *size);
 
 #endif /* CGIT_H */
diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index e69140b..70e4c78 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -1,505 +1,509 @@
 :man source:   cgit
 :man manual:   cgit
 
 CGITRC(5)
 ========
 
 
 NAME
 ----
 cgitrc - runtime configuration for cgit
 
 
 SYNOPSIS
 --------
 Cgitrc contains all runtime settings for cgit, including the list of git
 repositories, formatted as a line-separated list of NAME=VALUE pairs. Blank
 lines, and lines starting with '#', are ignored.
 
 
 LOCATION
 --------
 The default location of cgitrc, defined at compile time, is /etc/cgitrc. At
 runtime, cgit will consult the environment variable CGIT_CONFIG and, if
 defined, use its value instead.
 
 
 GLOBAL SETTINGS
 ---------------
 about-filter::
         Specifies a command which will be invoked to format the content of
         about pages (both top-level and for each repository). The command will
         get the content of the about-file on its STDIN, and the STDOUT from the
         command will be included verbatim on the about page. Default value:
         none.
 
 agefile::
         Specifies a path, relative to each repository path, which can be used
         to specify the date and time of the youngest commit in the repository.
         The first line in the file is used as input to the "parse_date"
         function in libgit. Recommended timestamp-format is "yyyy-mm-dd
         hh:mm:ss". Default value: "info/web/last-modified".
 
 cache-root::
         Path used to store the cgit cache entries. Default value:
         "/var/cache/cgit".
 
 cache-dynamic-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of repository pages accessed without a fixed SHA1. Default
         value: "5".
 
 cache-repo-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of the repository summary page. Default value: "5".
 
 cache-root-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of the repository index page. Default value: "5".
 
 cache-scanrc-ttl::
         Number which specifies the time-to-live, in minutes, for the result
         of scanning a path for git repositories. Default value: "15".
 
 cache-size::
         The maximum number of entries in the cgit cache. Default value: "0"
         (i.e. caching is disabled).
 
 cache-static-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of repository pages accessed with a fixed SHA1. Default value:
         "5".
 
 clone-prefix::
         Space-separated list of common prefixes which, when combined with a
         repository url, generates valid clone urls for the repository. This
         setting is only used if `repo.clone-url` is unspecified. Default value:
         none.
 
 commit-filter::
         Specifies a command which will be invoked to format commit messages.
         The command will get the message on its STDIN, and the STDOUT from the
         command will be included verbatim as the commit message, i.e. this can
         be used to implement bugtracker integration. Default value: none.
 
 css::
         Url which specifies the css document to include in all cgit pages.
         Default value: "/cgit.css".
 
 embedded::
         Flag which, when set to "1", will make cgit generate a html fragment
         suitable for embedding in other html pages. Default value: none. See
         also: "noheader".
         
 enable-filter-overrides::
         Flag which, when set to "1", allows all filter settings to be
         overridden in repository-specific cgitrc files. Default value: none.
 
 enable-index-links::
         Flag which, when set to "1", will make cgit generate extra links for
         each repo in the repository index (specifically, to the "summary",
         "commit" and "tree" pages). Default value: "0".
 
 enable-log-filecount::
         Flag which, when set to "1", will make cgit print the number of
         modified files for each commit on the repository log page. Default
         value: "0".
 
 enable-log-linecount::
         Flag which, when set to "1", will make cgit print the number of added
         and removed lines for each commit on the repository log page. Default
         value: "0".
 
 enable-tree-linenumbers::
         Flag which, when set to "1", will make cgit generate linenumber links
         for plaintext blobs printed in the tree view. Default value: "1".
 
 favicon::
         Url used as link to a shortcut icon for cgit. If specified, it is
         suggested to use the value "/favicon.ico" since certain browsers will
         ignore other values. Default value: none.
 
 footer::
         The content of the file specified with this option will be included
         verbatim at the bottom of all pages (i.e. it replaces the standard
         "generated by..." message. Default value: none.
 
 head-include::
         The content of the file specified with this option will be included
         verbatim in the html HEAD section on all pages. Default value: none.
 
 header::
         The content of the file specified with this option will be included
         verbatim at the top of all pages. Default value: none.
 
 include::
         Name of a configfile to include before the rest of the current config-
         file is parsed. Default value: none.
 
 index-header::
         The content of the file specified with this option will be included
         verbatim above the repository index. This setting is deprecated, and
         will not be supported by cgit-1.0 (use root-readme instead). Default
         value: none.
 
 index-info::
         The content of the file specified with this option will be included
         verbatim below the heading on the repository index page. This setting
         is deprecated, and will not be supported by cgit-1.0 (use root-desc
         instead). Default value: none.
 
 local-time::
         Flag which, if set to "1", makes cgit print commit and tag times in the
         servers timezone. Default value: "0".
 
 logo::
         Url which specifies the source of an image which will be used as a logo
         on all cgit pages. Default value: "/cgit.png".
 
 logo-link::
         Url loaded when clicking on the cgit logo image. If unspecified the
         calculated url of the repository index page will be used. Default
         value: none.
 
 max-commit-count::
         Specifies the number of entries to list per page in "log" view. Default
         value: "50".
 
 max-message-length::
         Specifies the maximum number of commit message characters to display in
         "log" view. Default value: "80".
 
 max-repo-count::
                 Specifies the number of entries to list per page on therepository
         index page. Default value: "50".
 
 max-repodesc-length::
         Specifies the maximum number of repo description characters to display
         on the repository index page. Default value: "80".
 
 max-blob-size::
         Specifies the maximum size of a blob to display HTML for in KBytes.
         Default value: "0" (limit disabled).
 
 max-stats::
         Set the default maximum statistics period. Valid values are "week",
         "month", "quarter" and "year". If unspecified, statistics are
         disabled. Default value: none. See also: "repo.max-stats".
 
 mimetype.<ext>::
         Set the mimetype for the specified filename extension. This is used
         by the `plain` command when returning blob content.
 
 module-link::
         Text which will be used as the formatstring for a hyperlink when a
         submodule is printed in a directory listing. The arguments for the
         formatstring are the path and SHA1 of the submodule commit. Default
         value: "./?repo=%s&page=commit&id=%s"
 
 nocache::
         If set to the value "1" caching will be disabled. This settings is
         deprecated, and will not be honored starting with cgit-1.0. Default
         value: "0".
 
 noplainemail::
         If set to "1" showing full author email adresses will be disabled.
         Default value: "0".
 
 noheader::
         Flag which, when set to "1", will make cgit omit the standard header
         on all pages. Default value: none. See also: "embedded".
 
 renamelimit::
         Maximum number of files to consider when detecting renames. The value
          "-1" uses the compiletime value in git (for further info, look at
           `man git-diff`). Default value: "-1".
 
 repo.group::
         Legacy alias for "section". This option is deprecated and will not be
         supported in cgit-1.0.
 
 robots::
         Text used as content for the "robots" meta-tag. Default value:
         "index, nofollow".
 
 root-desc::
         Text printed below the heading on the repository index page. Default
         value: "a fast webinterface for the git dscm".
 
 root-readme::
         The content of the file specified with this option will be included
         verbatim below the "about" link on the repository index page. Default
         value: none.
 
 root-title::
         Text printed as heading on the repository index page. Default value:
         "Git Repository Browser".
 
 scan-path::
         A path which will be scanned for repositories. If caching is enabled,
         the result will be cached as a cgitrc include-file in the cache
         directory. Default value: none. See also: cache-scanrc-ttl.
 
 section::
         The name of the current repository section - all repositories defined
         after this option will inherit the current section name. Default value:
         none.
 
+side-by-side-diffs::
+        If set to "1" shows side-by-side diffs instead of unidiffs per
+        default. Default value: "0".
+
 snapshots::
         Text which specifies the default set of snapshot formats generated by
         cgit. The value is a space-separated list of zero or more of the
         values "tar", "tar.gz", "tar.bz2" and "zip". Default value: none.
 
 source-filter::
         Specifies a command which will be invoked to format plaintext blobs
         in the tree view. The command will get the blob content on its STDIN
         and the name of the blob as its only command line argument. The STDOUT
         from the command will be included verbatim as the blob contents, i.e.
         this can be used to implement e.g. syntax highlighting. Default value:
         none.
 
 summary-branches::
         Specifies the number of branches to display in the repository "summary"
         view. Default value: "10".
 
 summary-log::
         Specifies the number of log entries to display in the repository
         "summary" view. Default value: "10".
 
 summary-tags::
         Specifies the number of tags to display in the repository "summary"
         view. Default value: "10".
 
 virtual-root::
         Url which, if specified, will be used as root for all cgit links. It
         will also cause cgit to generate 'virtual urls', i.e. urls like
         '/cgit/tree/README' as opposed to '?r=cgit&p=tree&path=README'. Default
         value: none.
         NOTE: cgit has recently learned how to use PATH_INFO to achieve the
         same kind of virtual urls, so this option will probably be deprecated.
 
 REPOSITORY SETTINGS
 -------------------
 repo.about-filter::
         Override the default about-filter. Default value: none. See also:
         "enable-filter-overrides".
 
 repo.clone-url::
         A list of space-separated urls which can be used to clone this repo.
         Default value: none.
 
 repo.commit-filter::
         Override the default commit-filter. Default value: none. See also:
         "enable-filter-overrides".
 
 repo.defbranch::
         The name of the default branch for this repository. If no such branch
         exists in the repository, the first branch name (when sorted) is used
         as default instead. Default value: "master".
 
 repo.desc::
         The value to show as repository description. Default value: none.
 
 repo.enable-log-filecount::
         A flag which can be used to disable the global setting
         `enable-log-filecount'. Default value: none.
 
 repo.enable-log-linecount::
         A flag which can be used to disable the global setting
         `enable-log-linecount'. Default value: none.
 
 repo.max-stats::
         Override the default maximum statistics period. Valid values are equal
         to the values specified for the global "max-stats" setting. Default
         value: none.
 
 repo.name::
         The value to show as repository name. Default value: <repo.url>.
 
 repo.owner::
         A value used to identify the owner of the repository. Default value:
         none.
 
 repo.path::
         An absolute path to the repository directory. For non-bare repositories
         this is the .git-directory. Default value: none.
 
 repo.readme::
         A path (relative to <repo.path>) which specifies a file to include
         verbatim as the "About" page for this repo. Default value: none.
 
 repo.snapshots::
         A mask of allowed snapshot-formats for this repo, restricted by the
         "snapshots" global setting. Default value: <snapshots>.
 
 repo.section::
         Override the current section name for this repository. Default value:
         none.
 
 repo.source-filter::
         Override the default source-filter. Default value: none. See also:
         "enable-filter-overrides".
 
 repo.url::
         The relative url used to access the repository. This must be the first
         setting specified for each repo. Default value: none.
 
 
 REPOSITORY-SPECIFIC CGITRC FILE
 -------------------------------
 When the option "scan-path" is used to auto-discover git repositories, cgit
 will try to parse the file "cgitrc" within any found repository. Such a
 repo-specific config file may contain any of the repo-specific options
 described above, except "repo.url" and "repo.path". Additionally, the "filter"
 options are only acknowledged in repo-specific config files when
 "enable-filter-overrides" is set to "1".
 
 Note: the "repo." prefix is dropped from the option names in repo-specific
 config files, e.g. "repo.desc" becomes "desc".
 
 
 EXAMPLE CGITRC FILE
 -------------------
 
 ....
 # Enable caching of up to 1000 output entriess
 cache-size=1000
 
 
 # Specify some default clone prefixes
 clone-prefix=git://foobar.com ssh://foobar.com/pub/git http://foobar.com/git
 
 # Specify the css url
 css=/css/cgit.css
 
 
 # Show extra links for each repository on the index page
 enable-index-links=1
 
 
 # Show number of affected files per commit on the log pages
 enable-log-filecount=1
 
 
 # Show number of added/removed lines per commit on the log pages
 enable-log-linecount=1
 
 
 # Add a cgit favicon
 favicon=/favicon.ico
 
 
 # Use a custom logo
 logo=/img/mylogo.png
 
 
 # Enable statistics per week, month and quarter
 max-stats=quarter
 
 
 # Set the title and heading of the repository index page
 root-title=foobar.com git repositories
 
 
 # Set a subheading for the repository index page
 root-desc=tracking the foobar development
 
 
 # Include some more info about foobar.com on the index page
 root-readme=/var/www/htdocs/about.html
 
 
 # Allow download of tar.gz, tar.bz2 and zip-files
 snapshots=tar.gz tar.bz2 zip
 
 
 ##
 ## List of common mimetypes
 ##
 
 mimetype.git=image/git
 mimetype.html=text/html
 mimetype.jpg=image/jpeg
 mimetype.jpeg=image/jpeg
 mimetype.pdf=application/pdf
 mimetype.png=image/png
 mimetype.svg=image/svg+xml
 
 
 ##
 ## List of repositories.
 ## PS: Any repositories listed when section is unset will not be
 ##     displayed under a section heading
 ## PPS: This list could be kept in a different file (e.g. '/etc/cgitrepos')
 ##      and included like this:
 ##        include=/etc/cgitrepos
 ##
 
 
 repo.url=foo
 repo.path=/pub/git/foo.git
 repo.desc=the master foo repository
 repo.owner=fooman@foobar.com
 repo.readme=info/web/about.html
 
 
 repo.url=bar
 repo.path=/pub/git/bar.git
 repo.desc=the bars for your foo
 repo.owner=barman@foobar.com
 repo.readme=info/web/about.html
 
 
 # The next repositories will be displayed under the 'extras' heading
 section=extras
 
 
 repo.url=baz
 repo.path=/pub/git/baz.git
 repo.desc=a set of extensions for bar users
 
 repo.url=wiz
 repo.path=/pub/git/wiz.git
 repo.desc=the wizard of foo
 
 
 # Add some mirrored repositories
 section=mirrors
 
 
 repo.url=git
 repo.path=/pub/git/git.git
 repo.desc=the dscm
 
 
 repo.url=linux
 repo.path=/pub/git/linux.git
 repo.desc=the kernel
 
 # Disable adhoc downloads of this repo
 repo.snapshots=0
 
 # Disable line-counts for this repo
 repo.enable-log-linecount=0
 
 # Restrict the max statistics period for this repo
 repo.max-stats=month
 ....
 
 
 BUGS
 ----
 Comments currently cannot appear on the same line as a setting; the comment
 will be included as part of the value. E.g. this line:
 
         robots=index  # allow indexing
 
 will generate the following html element:
 
         <meta name='robots' content='index  # allow indexing'/>
 
 
 
 AUTHOR
 ------
 Lars Hjemli <hjemli@gmail.com>
diff --git a/ui-commit.c b/ui-commit.c
index f5b0ae5..b5e3c01 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -1,118 +1,123 @@
 /* ui-commit.c: generate commit view
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "html.h"
 #include "ui-shared.h"
 #include "ui-diff.h"
 #include "ui-log.h"
 
 void cgit_print_commit(char *hex)
 {
         struct commit *commit, *parent;
         struct commitinfo *info;
         struct commit_list *p;
         unsigned char sha1[20];
         char *tmp;
         int parents = 0;
 
         if (!hex)
                 hex = ctx.qry.head;
 
         if (get_sha1(hex, sha1)) {
                 cgit_print_error(fmt("Bad object id: %s", hex));
                 return;
         }
         commit = lookup_commit_reference(sha1);
         if (!commit) {
                 cgit_print_error(fmt("Bad commit reference: %s", hex));
                 return;
         }
         info = cgit_parse_commit(commit);
 
         load_ref_decorations(DECORATE_FULL_REFS);
 
         html("<table summary='commit info' class='commit-info'>\n");
         html("<tr><th>author</th><td>");
         html_txt(info->author);
         if (!ctx.cfg.noplainemail) {
                 html(" ");
                 html_txt(info->author_email);
         }
         html("</td><td class='right'>");
         cgit_print_date(info->author_date, FMT_LONGDATE, ctx.cfg.local_time);
         html("</td></tr>\n");
         html("<tr><th>committer</th><td>");
         html_txt(info->committer);
         if (!ctx.cfg.noplainemail) {
                 html(" ");
                 html_txt(info->committer_email);
         }
         html("</td><td class='right'>");
         cgit_print_date(info->committer_date, FMT_LONGDATE, ctx.cfg.local_time);
         html("</td></tr>\n");
         html("<tr><th>commit</th><td colspan='2' class='sha1'>");
         tmp = sha1_to_hex(commit->object.sha1);
-        cgit_commit_link(tmp, NULL, NULL, ctx.qry.head, tmp);
+        cgit_commit_link(tmp, NULL, NULL, ctx.qry.head, tmp, 0);
         html(" (");
         cgit_patch_link("patch", NULL, NULL, NULL, tmp);
+        html(") (");
+        if ((ctx.qry.ssdiff && !ctx.cfg.ssdiff) || (!ctx.qry.ssdiff && ctx.cfg.ssdiff))
+                cgit_commit_link("unidiff", NULL, NULL, ctx.qry.head, tmp, 1);
+        else
+                cgit_commit_link("side-by-side diff", NULL, NULL, ctx.qry.head, tmp, 1);
         html(")</td></tr>\n");
         html("<tr><th>tree</th><td colspan='2' class='sha1'>");
         tmp = xstrdup(hex);
         cgit_tree_link(sha1_to_hex(commit->tree->object.sha1), NULL, NULL,
                        ctx.qry.head, tmp, NULL);
         html("</td></tr>\n");
               for (p = commit->parents; p ; p = p->next) {
                 parent = lookup_commit_reference(p->item->object.sha1);
                 if (!parent) {
                         html("<tr><td colspan='3'>");
                         cgit_print_error("Error reading parent commit");
                         html("</td></tr>");
                         continue;
                 }
                 html("<tr><th>parent</th>"
                      "<td colspan='2' class='sha1'>");
                 cgit_commit_link(sha1_to_hex(p->item->object.sha1), NULL, NULL,
-                                 ctx.qry.head, sha1_to_hex(p->item->object.sha1));
+                                 ctx.qry.head, sha1_to_hex(p->item->object.sha1), 0);
                 html(" (");
                 cgit_diff_link("diff", NULL, NULL, ctx.qry.head, hex,
-                               sha1_to_hex(p->item->object.sha1), NULL);
+                               sha1_to_hex(p->item->object.sha1), NULL, 0);
                 html(")</td></tr>");
                 parents++;
         }
         if (ctx.repo->snapshots) {
                 html("<tr><th>download</th><td colspan='2' class='sha1'>");
                 cgit_print_snapshot_links(ctx.qry.repo, ctx.qry.head,
                                           hex, ctx.repo->snapshots);
                 html("</td></tr>");
         }
         html("</table>\n");
         html("<div class='commit-subject'>");
         if (ctx.repo->commit_filter)
                 cgit_open_filter(ctx.repo->commit_filter);
         html_txt(info->subject);
         if (ctx.repo->commit_filter)
                 cgit_close_filter(ctx.repo->commit_filter);
         show_commit_decorations(commit);
         html("</div>");
         html("<div class='commit-msg'>");
         if (ctx.repo->commit_filter)
                 cgit_open_filter(ctx.repo->commit_filter);
         html_txt(info->msg);
         if (ctx.repo->commit_filter)
                 cgit_close_filter(ctx.repo->commit_filter);
         html("</div>");
         if (parents < 3) {
                 if (parents)
                         tmp = sha1_to_hex(commit->parents->item->object.sha1);
                 else
                         tmp = NULL;
                 cgit_print_diff(ctx.qry.sha1, tmp, NULL);
         }
         cgit_free_commitinfo(info);
 }
diff --git a/ui-diff.c b/ui-diff.c
index 2196745..a92a768 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -1,313 +1,353 @@
 /* ui-diff.c: show diff between two blobs
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "html.h"
 #include "ui-shared.h"
+#include "ui-ssdiff.h"
 
 unsigned char old_rev_sha1[20];
 unsigned char new_rev_sha1[20];
 
 static int files, slots;
 static int total_adds, total_rems, max_changes;
 static int lines_added, lines_removed;
 
 static struct fileinfo {
         char status;
         unsigned char old_sha1[20];
         unsigned char new_sha1[20];
         unsigned short old_mode;
         unsigned short new_mode;
         char *old_path;
         char *new_path;
         unsigned int added;
         unsigned int removed;
         unsigned long old_size;
         unsigned long new_size;
         int binary:1;
 } *items;
 
+static int use_ssdiff = 0;
 
 static void print_fileinfo(struct fileinfo *info)
 {
         char *class;
 
         switch (info->status) {
         case DIFF_STATUS_ADDED:
                 class = "add";
                 break;
         case DIFF_STATUS_COPIED:
                 class = "cpy";
                 break;
         case DIFF_STATUS_DELETED:
                 class = "del";
                 break;
         case DIFF_STATUS_MODIFIED:
                 class = "upd";
                 break;
         case DIFF_STATUS_RENAMED:
                 class = "mov";
                 break;
         case DIFF_STATUS_TYPE_CHANGED:
                 class = "typ";
                 break;
         case DIFF_STATUS_UNKNOWN:
                 class = "unk";
                 break;
         case DIFF_STATUS_UNMERGED:
                 class = "stg";
                 break;
         default:
                 die("bug: unhandled diff status %c", info->status);
         }
 
         html("<tr>");
         htmlf("<td class='mode'>");
         if (is_null_sha1(info->new_sha1)) {
                 cgit_print_filemode(info->old_mode);
         } else {
                 cgit_print_filemode(info->new_mode);
         }
 
         if (info->old_mode != info->new_mode &&
             !is_null_sha1(info->old_sha1) &&
             !is_null_sha1(info->new_sha1)) {
                 html("<span class='modechange'>[");
                 cgit_print_filemode(info->old_mode);
                 html("]</span>");
         }
         htmlf("</td><td class='%s'>", class);
         cgit_diff_link(info->new_path, NULL, NULL, ctx.qry.head, ctx.qry.sha1,
-                       ctx.qry.sha2, info->new_path);
+                       ctx.qry.sha2, info->new_path, 0);
         if (info->status == DIFF_STATUS_COPIED || info->status == DIFF_STATUS_RENAMED)
                 htmlf(" (%s from %s)",
                       info->status == DIFF_STATUS_COPIED ? "copied" : "renamed",
                       info->old_path);
         html("</td><td class='right'>");
         if (info->binary) {
                 htmlf("bin</td><td class='graph'>%d -> %d bytes",
                       info->old_size, info->new_size);
                 return;
         }
         htmlf("%d", info->added + info->removed);
         html("</td><td class='graph'>");
         htmlf("<table summary='file diffstat' width='%d%%'><tr>", (max_changes > 100 ? 100 : max_changes));
         htmlf("<td class='add' style='width: %.1f%%;'/>",
               info->added * 100.0 / max_changes);
         htmlf("<td class='rem' style='width: %.1f%%;'/>",
               info->removed * 100.0 / max_changes);
         htmlf("<td class='none' style='width: %.1f%%;'/>",
               (max_changes - info->removed - info->added) * 100.0 / max_changes);
         html("</tr></table></td></tr>\n");
 }
 
 static void count_diff_lines(char *line, int len)
 {
         if (line && (len > 0)) {
                 if (line[0] == '+')
                         lines_added++;
                 else if (line[0] == '-')
                         lines_removed++;
         }
 }
 
 static void inspect_filepair(struct diff_filepair *pair)
 {
         int binary = 0;
         unsigned long old_size = 0;
         unsigned long new_size = 0;
         files++;
         lines_added = 0;
         lines_removed = 0;
         cgit_diff_files(pair->one->sha1, pair->two->sha1, &old_size, &new_size,
                         &binary, count_diff_lines);
         if (files >= slots) {
                 if (slots == 0)
                         slots = 4;
                 else
                         slots = slots * 2;
                 items = xrealloc(items, slots * sizeof(struct fileinfo));
         }
         items[files-1].status = pair->status;
         hashcpy(items[files-1].old_sha1, pair->one->sha1);
         hashcpy(items[files-1].new_sha1, pair->two->sha1);
         items[files-1].old_mode = pair->one->mode;
         items[files-1].new_mode = pair->two->mode;
         items[files-1].old_path = xstrdup(pair->one->path);
         items[files-1].new_path = xstrdup(pair->two->path);
         items[files-1].added = lines_added;
         items[files-1].removed = lines_removed;
         items[files-1].old_size = old_size;
         items[files-1].new_size = new_size;
         items[files-1].binary = binary;
         if (lines_added + lines_removed > max_changes)
                 max_changes = lines_added + lines_removed;
         total_adds += lines_added;
         total_rems += lines_removed;
 }
 
 void cgit_print_diffstat(const unsigned char *old_sha1,
                          const unsigned char *new_sha1)
 {
         int i;
 
         html("<div class='diffstat-header'>");
         cgit_diff_link("Diffstat", NULL, NULL, ctx.qry.head, ctx.qry.sha1,
-                       ctx.qry.sha2, NULL);
+                       ctx.qry.sha2, NULL, 0);
         html("</div>");
         html("<table summary='diffstat' class='diffstat'>");
         max_changes = 0;
         cgit_diff_tree(old_sha1, new_sha1, inspect_filepair, NULL);
         for(i = 0; i<files; i++)
                 print_fileinfo(&items[i]);
         html("</table>");
         html("<div class='diffstat-summary'>");
         htmlf("%d files changed, %d insertions, %d deletions",
               files, total_adds, total_rems);
         html("</div>");
 }
 
 
 /*
  * print a single line returned from xdiff
  */
 static void print_line(char *line, int len)
 {
         char *class = "ctx";
         char c = line[len-1];
 
         if (line[0] == '+')
                 class = "add";
         else if (line[0] == '-')
                 class = "del";
         else if (line[0] == '@')
                 class = "hunk";
 
         htmlf("<div class='%s'>", class);
         line[len-1] = '\0';
         html_txt(line);
         html("</div>");
         line[len-1] = c;
 }
 
 static void header(unsigned char *sha1, char *path1, int mode1,
                    unsigned char *sha2, char *path2, int mode2)
 {
         char *abbrev1, *abbrev2;
         int subproject;
 
         subproject = (S_ISGITLINK(mode1) || S_ISGITLINK(mode2));
         html("<div class='head'>");
         html("diff --git a/");
         html_txt(path1);
         html(" b/");
         html_txt(path2);
 
         if (is_null_sha1(sha1))
                 path1 = "dev/null";
         if (is_null_sha1(sha2))
                 path2 = "dev/null";
 
         if (mode1 == 0)
                 htmlf("<br/>new file mode %.6o", mode2);
 
         if (mode2 == 0)
                 htmlf("<br/>deleted file mode %.6o", mode1);
 
         if (!subproject) {
                 abbrev1 = xstrdup(find_unique_abbrev(sha1, DEFAULT_ABBREV));
                 abbrev2 = xstrdup(find_unique_abbrev(sha2, DEFAULT_ABBREV));
                 htmlf("<br/>index %s..%s", abbrev1, abbrev2);
                 free(abbrev1);
                 free(abbrev2);
                 if (mode1 != 0 && mode2 != 0) {
                         htmlf(" %.6o", mode1);
                         if (mode2 != mode1)
                                 htmlf("..%.6o", mode2);
                 }
                 html("<br/>--- a/");
                 if (mode1 != 0)
                         cgit_tree_link(path1, NULL, NULL, ctx.qry.head,
                                        sha1_to_hex(old_rev_sha1), path1);
                 else
                         html_txt(path1);
                 html("<br/>+++ b/");
                 if (mode2 != 0)
                         cgit_tree_link(path2, NULL, NULL, ctx.qry.head,
                                        sha1_to_hex(new_rev_sha1), path2);
                 else
                         html_txt(path2);
         }
         html("</div>");
 }
 
+static void print_ssdiff_link()
+{
+        if (!strcmp(ctx.qry.page, "diff")) {
+                if (use_ssdiff)
+                        cgit_diff_link("Unidiff", NULL, NULL, ctx.qry.head,
+                                       ctx.qry.sha1, ctx.qry.sha2, ctx.qry.path, 1);
+                else
+                        cgit_diff_link("Side-by-side diff", NULL, NULL,
+                                       ctx.qry.head, ctx.qry.sha1,
+                                       ctx.qry.sha2, ctx.qry.path, 1);
+        }
+}
+
 static void filepair_cb(struct diff_filepair *pair)
 {
         unsigned long old_size = 0;
         unsigned long new_size = 0;
         int binary = 0;
+        linediff_fn print_line_fn = print_line;
 
+        if (use_ssdiff) {
+                cgit_ssdiff_header_begin();
+                print_line_fn = cgit_ssdiff_line_cb;
+        }
         header(pair->one->sha1, pair->one->path, pair->one->mode,
                pair->two->sha1, pair->two->path, pair->two->mode);
+        if (use_ssdiff)
+                cgit_ssdiff_header_end();
         if (S_ISGITLINK(pair->one->mode) || S_ISGITLINK(pair->two->mode)) {
                 if (S_ISGITLINK(pair->one->mode))
-                        print_line(fmt("-Subproject %s", sha1_to_hex(pair->one->sha1)), 52);
+                        print_line_fn(fmt("-Subproject %s", sha1_to_hex(pair->one->sha1)), 52);
                 if (S_ISGITLINK(pair->two->mode))
-                        print_line(fmt("+Subproject %s", sha1_to_hex(pair->two->sha1)), 52);
+                        print_line_fn(fmt("+Subproject %s", sha1_to_hex(pair->two->sha1)), 52);
+                if (use_ssdiff)
+                        cgit_ssdiff_footer();
                 return;
         }
-        if (cgit_diff_files(pair->one->sha1, pair->two->sha1, &old_size, 
-                            &new_size, &binary, print_line))
+        if (cgit_diff_files(pair->one->sha1, pair->two->sha1, &old_size,
+                            &new_size, &binary, print_line_fn))
                 cgit_print_error("Error running diff");
-        if (binary)
-                html("Binary files differ");
+        if (binary) {
+                if (use_ssdiff)
+                        html("<tr><td colspan='4'>Binary files differ</td></tr>");
+                else
+                        html("Binary files differ");
+        }
+        if (use_ssdiff)
+                cgit_ssdiff_footer();
 }
 
 void cgit_print_diff(const char *new_rev, const char *old_rev, const char *prefix)
 {
         enum object_type type;
         unsigned long size;
         struct commit *commit, *commit2;
 
         if (!new_rev)
                 new_rev = ctx.qry.head;
         get_sha1(new_rev, new_rev_sha1);
         type = sha1_object_info(new_rev_sha1, &size);
         if (type == OBJ_BAD) {
                 cgit_print_error(fmt("Bad object name: %s", new_rev));
                 return;
         }
         commit = lookup_commit_reference(new_rev_sha1);
         if (!commit || parse_commit(commit))
                 cgit_print_error(fmt("Bad commit: %s", sha1_to_hex(new_rev_sha1)));
 
         if (old_rev)
                 get_sha1(old_rev, old_rev_sha1);
         else if (commit->parents && commit->parents->item)
                 hashcpy(old_rev_sha1, commit->parents->item->object.sha1);
         else
                 hashclr(old_rev_sha1);
 
         if (!is_null_sha1(old_rev_sha1)) {
                 type = sha1_object_info(old_rev_sha1, &size);
                 if (type == OBJ_BAD) {
                         cgit_print_error(fmt("Bad object name: %s", sha1_to_hex(old_rev_sha1)));
                         return;
                 }
                 commit2 = lookup_commit_reference(old_rev_sha1);
                 if (!commit2 || parse_commit(commit2))
                         cgit_print_error(fmt("Bad commit: %s", sha1_to_hex(old_rev_sha1)));
         }
+
+        if ((ctx.qry.ssdiff && !ctx.cfg.ssdiff) || (!ctx.qry.ssdiff && ctx.cfg.ssdiff))
+                use_ssdiff = 1;
+
+        print_ssdiff_link();
         cgit_print_diffstat(old_rev_sha1, new_rev_sha1);
 
-        html("<table summary='diff' class='diff'>");
-        html("<tr><td>");
+        if (use_ssdiff) {
+                html("<table summary='ssdiff' class='ssdiff'>");
+        } else {
+                html("<table summary='diff' class='diff'>");
+                html("<tr><td>");
+        }
         cgit_diff_tree(old_rev_sha1, new_rev_sha1, filepair_cb, prefix);
-        html("</td></tr>");
+        if (!use_ssdiff)
+                html("</td></tr>");
         html("</table>");
 }
diff --git a/ui-log.c b/ui-log.c
index f3132c9..0947604 100644
--- a/ui-log.c
+++ b/ui-log.c
@@ -1,234 +1,234 @@
 /* ui-log.c: functions for log output
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "html.h"
 #include "ui-shared.h"
 
 int files, add_lines, rem_lines;
 
 void count_lines(char *line, int size)
 {
         if (size <= 0)
                 return;
 
         if (line[0] == '+')
                 add_lines++;
 
         else if (line[0] == '-')
                 rem_lines++;
 }
 
 void inspect_files(struct diff_filepair *pair)
 {
         unsigned long old_size = 0;
         unsigned long new_size = 0;
         int binary = 0;
 
         files++;
         if (ctx.repo->enable_log_linecount)
                 cgit_diff_files(pair->one->sha1, pair->two->sha1, &old_size,
                                 &new_size, &binary, count_lines);
 }
 
 void show_commit_decorations(struct commit *commit)
 {
         struct name_decoration *deco;
         static char buf[1024];
 
         buf[sizeof(buf) - 1] = 0;
         deco = lookup_decoration(&name_decoration, &commit->object);
         while (deco) {
                 if (!prefixcmp(deco->name, "refs/heads/")) {
                         strncpy(buf, deco->name + 11, sizeof(buf) - 1);
                         cgit_log_link(buf, NULL, "branch-deco", buf, NULL, NULL,
                                 0, NULL, NULL, ctx.qry.showmsg);
                 }
                 else if (!prefixcmp(deco->name, "tag: refs/tags/")) {
                         strncpy(buf, deco->name + 15, sizeof(buf) - 1);
                         cgit_tag_link(buf, NULL, "tag-deco", ctx.qry.head, buf);
                 }
                 else if (!prefixcmp(deco->name, "refs/tags/")) {
                         strncpy(buf, deco->name + 10, sizeof(buf) - 1);
                         cgit_tag_link(buf, NULL, "tag-deco", ctx.qry.head, buf);
                 }
                 else if (!prefixcmp(deco->name, "refs/remotes/")) {
                         strncpy(buf, deco->name + 13, sizeof(buf) - 1);
                         cgit_log_link(buf, NULL, "remote-deco", NULL,
                                 sha1_to_hex(commit->object.sha1), NULL,
                                 0, NULL, NULL, ctx.qry.showmsg);
                 }
                 else {
                         strncpy(buf, deco->name, sizeof(buf) - 1);
                         cgit_commit_link(buf, NULL, "deco", ctx.qry.head,
-                                sha1_to_hex(commit->object.sha1));
+                                sha1_to_hex(commit->object.sha1), 0);
                 }
                 deco = deco->next;
         }
 }
 
 void print_commit(struct commit *commit)
 {
         struct commitinfo *info;
         char *tmp;
         int cols = 2;
 
         info = cgit_parse_commit(commit);
         htmlf("<tr%s><td>",
                 ctx.qry.showmsg ? " class='logheader'" : "");
         tmp = fmt("id=%s", sha1_to_hex(commit->object.sha1));
         tmp = cgit_pageurl(ctx.repo->url, "commit", tmp);
         html_link_open(tmp, NULL, NULL);
         cgit_print_age(commit->date, TM_WEEK * 2, FMT_SHORTDATE);
         html_link_close();
         htmlf("</td><td%s>",
                 ctx.qry.showmsg ? " class='logsubject'" : "");
         cgit_commit_link(info->subject, NULL, NULL, ctx.qry.head,
-                         sha1_to_hex(commit->object.sha1));
+                         sha1_to_hex(commit->object.sha1), 0);
         show_commit_decorations(commit);
         html("</td><td>");
         html_txt(info->author);
         if (ctx.repo->enable_log_filecount) {
                 files = 0;
                 add_lines = 0;
                 rem_lines = 0;
                 cgit_diff_commit(commit, inspect_files);
                 html("</td><td>");
                 htmlf("%d", files);
                 if (ctx.repo->enable_log_linecount) {
                         html("</td><td>");
                         htmlf("-%d/+%d", rem_lines, add_lines);
                 }
         }
         html("</td></tr>\n");
         if (ctx.qry.showmsg) {
                 if (ctx.repo->enable_log_filecount) {
                         cols++;
                         if (ctx.repo->enable_log_linecount)
                                 cols++;
                 }
                 htmlf("<tr class='nohover'><td/><td colspan='%d' class='logmsg'>",
                         cols);
                 html_txt(info->msg);
                 html("</td></tr>\n");
         }
         cgit_free_commitinfo(info);
 }
 
 static const char *disambiguate_ref(const char *ref)
 {
         unsigned char sha1[20];
         const char *longref;
 
         longref = fmt("refs/heads/%s", ref);
         if (get_sha1(longref, sha1) == 0)
                 return longref;
 
         return ref;
 }
 
 void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern,
                     char *path, int pager)
 {
         struct rev_info rev;
         struct commit *commit;
         const char *argv[] = {NULL, NULL, NULL, NULL, NULL};
         int argc = 2;
         int i, columns = 3;
 
         if (!tip)
                 tip = ctx.qry.head;
 
         argv[1] = disambiguate_ref(tip);
 
         if (grep && pattern && (!strcmp(grep, "grep") ||
                                 !strcmp(grep, "author") ||
                                 !strcmp(grep, "committer")))
                 argv[argc++] = fmt("--%s=%s", grep, pattern);
 
         if (path) {
                 argv[argc++] = "--";
                 argv[argc++] = path;
         }
         init_revisions(&rev, NULL);
         rev.abbrev = DEFAULT_ABBREV;
         rev.commit_format = CMIT_FMT_DEFAULT;
         rev.verbose_header = 1;
         rev.show_root_diff = 0;
         setup_revisions(argc, argv, &rev, NULL);
         load_ref_decorations(DECORATE_FULL_REFS);
         rev.show_decorations = 1;
         rev.grep_filter.regflags |= REG_ICASE;
         compile_grep_patterns(&rev.grep_filter);
         prepare_revision_walk(&rev);
 
         if (pager)
                 html("<table class='list nowrap'>");
 
         html("<tr class='nohover'><th class='left'>Age</th>"
               "<th class='left'>Commit message");
         if (pager) {
                 html(" (");
                 cgit_log_link(ctx.qry.showmsg ? "Collapse" : "Expand", NULL,
                               NULL, ctx.qry.head, ctx.qry.sha1,
                               ctx.qry.path, ctx.qry.ofs, ctx.qry.grep,
                               ctx.qry.search, ctx.qry.showmsg ? 0 : 1);
                 html(")");
         }
         html("</th><th class='left'>Author</th>");
         if (ctx.repo->enable_log_filecount) {
                 html("<th class='left'>Files</th>");
                 columns++;
                 if (ctx.repo->enable_log_linecount) {
                         html("<th class='left'>Lines</th>");
                         columns++;
                 }
         }
         html("</tr>\n");
 
         if (ofs<0)
                 ofs = 0;
 
         for (i = 0; i < ofs && (commit = get_revision(&rev)) != NULL; i++) {
                 free(commit->buffer);
                 commit->buffer = NULL;
                 free_commit_list(commit->parents);
                 commit->parents = NULL;
         }
 
         for (i = 0; i < cnt && (commit = get_revision(&rev)) != NULL; i++) {
                 print_commit(commit);
                 free(commit->buffer);
                 commit->buffer = NULL;
                 free_commit_list(commit->parents);
                 commit->parents = NULL;
         }
         if (pager) {
                 htmlf("</table><div class='pager'>",
                      columns);
                 if (ofs > 0) {
                         cgit_log_link("[prev]", NULL, NULL, ctx.qry.head,
                                       ctx.qry.sha1, ctx.qry.path,
                                       ofs - cnt, ctx.qry.grep,
                                       ctx.qry.search, ctx.qry.showmsg);
                         html("&nbsp;");
                 }
                 if ((commit = get_revision(&rev)) != NULL) {
                         cgit_log_link("[next]", NULL, NULL, ctx.qry.head,
                                       ctx.qry.sha1, ctx.qry.path,
                                       ofs + cnt, ctx.qry.grep,
                                       ctx.qry.search, ctx.qry.showmsg);
                 }
                 html("</div>");
         } else if ((commit = get_revision(&rev)) != NULL) {
                 html("<tr class='nohover'><td colspan='3'>");
                 cgit_log_link("[...]", NULL, NULL, ctx.qry.head, NULL, NULL, 0,
                               NULL, NULL, ctx.qry.showmsg);
                 html("</td></tr>\n");
         }
 }
diff --git a/ui-refs.c b/ui-refs.c
index d3b4f6e..33d9bec 100644
--- a/ui-refs.c
+++ b/ui-refs.c
@@ -1,245 +1,245 @@
 /* ui-refs.c: browse symbolic refs
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "html.h"
 #include "ui-shared.h"
 
 static int header;
 
 static int cmp_age(int age1, int age2)
 {
         if (age1 != 0 && age2 != 0)
                 return age2 - age1;
 
         if (age1 == 0 && age2 == 0)
                 return 0;
 
         if (age1 == 0)
                 return +1;
 
         return -1;
 }
 
 static int cmp_ref_name(const void *a, const void *b)
 {
         struct refinfo *r1 = *(struct refinfo **)a;
         struct refinfo *r2 = *(struct refinfo **)b;
 
         return strcmp(r1->refname, r2->refname);
 }
 
 static int cmp_branch_age(const void *a, const void *b)
 {
         struct refinfo *r1 = *(struct refinfo **)a;
         struct refinfo *r2 = *(struct refinfo **)b;
 
         return cmp_age(r1->commit->committer_date, r2->commit->committer_date);
 }
 
 static int cmp_tag_age(const void *a, const void *b)
 {
         struct refinfo *r1 = *(struct refinfo **)a;
         struct refinfo *r2 = *(struct refinfo **)b;
         int r1date, r2date;
 
         if (r1->object->type != OBJ_COMMIT)
                 r1date = r1->tag->tagger_date;
         else
                 r1date = r1->commit->committer_date;
 
         if (r2->object->type != OBJ_COMMIT)
                 r2date = r2->tag->tagger_date;
         else
                 r2date = r2->commit->committer_date;
 
         return cmp_age(r1date, r2date);
 }
 
 static int print_branch(struct refinfo *ref)
 {
         struct commitinfo *info = ref->commit;
         char *name = (char *)ref->refname;
 
         if (!info)
                 return 1;
         html("<tr><td>");
         cgit_log_link(name, NULL, NULL, name, NULL, NULL, 0, NULL, NULL,
                       ctx.qry.showmsg);
         html("</td><td>");
 
         if (ref->object->type == OBJ_COMMIT) {
-                cgit_commit_link(info->subject, NULL, NULL, name, NULL);
+                cgit_commit_link(info->subject, NULL, NULL, name, NULL, 0);
                 html("</td><td>");
                 html_txt(info->author);
                 html("</td><td colspan='2'>");
                 cgit_print_age(info->commit->date, -1, NULL);
         } else {
                 html("</td><td></td><td>");
                 cgit_object_link(ref->object);
         }
         html("</td></tr>\n");
         return 0;
 }
 
 static void print_tag_header()
 {
         html("<tr class='nohover'><th class='left'>Tag</th>"
              "<th class='left'>Download</th>"
              "<th class='left'>Author</th>"
              "<th class='left' colspan='2'>Age</th></tr>\n");
         header = 1;
 }
 
 static void print_tag_downloads(const struct cgit_repo *repo, const char *ref)
 {
         const struct cgit_snapshot_format* f;
             char *filename;
         const char *basename;
 
         if (!ref || strlen(ref) < 2)
                 return;
 
         basename = cgit_repobasename(repo->url);
         if (prefixcmp(ref, basename) != 0) {
                 if ((ref[0] == 'v' || ref[0] == 'V') && isdigit(ref[1]))
                         ref++;
                 if (isdigit(ref[0]))
                         ref = xstrdup(fmt("%s-%s", basename, ref));
         }
 
         for (f = cgit_snapshot_formats; f->suffix; f++) {
                 if (!(repo->snapshots & f->bit))
                         continue;
                 filename = fmt("%s%s", ref, f->suffix);
                 cgit_snapshot_link(filename, NULL, NULL, NULL, NULL, filename);
                 html("&nbsp;&nbsp;");
         }
 }
 static int print_tag(struct refinfo *ref)
 {
         struct tag *tag;
         struct taginfo *info;
         char *name = (char *)ref->refname;
 
         if (ref->object->type == OBJ_TAG) {
                 tag = (struct tag *)ref->object;
                 info = ref->tag;
                 if (!tag || !info)
                         return 1;
                 html("<tr><td>");
                 cgit_tag_link(name, NULL, NULL, ctx.qry.head, name);
                 html("</td><td>");
                 if (ctx.repo->snapshots && (tag->tagged->type == OBJ_COMMIT))
                         print_tag_downloads(ctx.repo, name);
                 else
                         cgit_object_link(tag->tagged);
                 html("</td><td>");
                 if (info->tagger)
                         html(info->tagger);
                 html("</td><td colspan='2'>");
                 if (info->tagger_date > 0)
                         cgit_print_age(info->tagger_date, -1, NULL);
                 html("</td></tr>\n");
         } else {
                 if (!header)
                         print_tag_header();
                 html("<tr><td>");
                 cgit_tag_link(name, NULL, NULL, ctx.qry.head, name);
                 html("</td><td>");
                 if (ctx.repo->snapshots && (ref->object->type == OBJ_COMMIT))
                         print_tag_downloads(ctx.repo, name);
                 else
                         cgit_object_link(ref->object);
                 html("</td><td>");
                 if (ref->object->type == OBJ_COMMIT)
                         html(ref->commit->author);
                 html("</td><td colspan='2'>");
                 if (ref->object->type == OBJ_COMMIT)
                         cgit_print_age(ref->commit->commit->date, -1, NULL);
                 html("</td></tr>\n");
         }
         return 0;
 }
 
 static void print_refs_link(char *path)
 {
         html("<tr class='nohover'><td colspan='4'>");
         cgit_refs_link("[...]", NULL, NULL, ctx.qry.head, NULL, path);
         html("</td></tr>");
 }
 
 void cgit_print_branches(int maxcount)
 {
         struct reflist list;
         int i;
 
         html("<tr class='nohover'><th class='left'>Branch</th>"
              "<th class='left'>Commit message</th>"
              "<th class='left'>Author</th>"
              "<th class='left' colspan='2'>Age</th></tr>\n");
 
         list.refs = NULL;
         list.alloc = list.count = 0;
         for_each_branch_ref(cgit_refs_cb, &list);
 
         if (maxcount == 0 || maxcount > list.count)
                 maxcount = list.count;
 
         if (maxcount < list.count) {
                 qsort(list.refs, list.count, sizeof(*list.refs), cmp_branch_age);
                 qsort(list.refs, maxcount, sizeof(*list.refs), cmp_ref_name);
         }
 
         for(i=0; i<maxcount; i++)
                 print_branch(list.refs[i]);
 
         if (maxcount < list.count)
                 print_refs_link("heads");
 }
 
 void cgit_print_tags(int maxcount)
 {
         struct reflist list;
         int i;
 
         header = 0;
         list.refs = NULL;
         list.alloc = list.count = 0;
         for_each_tag_ref(cgit_refs_cb, &list);
         if (list.count == 0)
                 return;
         qsort(list.refs, list.count, sizeof(*list.refs), cmp_tag_age);
         if (!maxcount)
                 maxcount = list.count;
         else if (maxcount > list.count)
                 maxcount = list.count;
         print_tag_header();
         for(i=0; i<maxcount; i++)
                 print_tag(list.refs[i]);
 
         if (maxcount < list.count)
                 print_refs_link("tags");
 }
 
 void cgit_print_refs()
 {
 
         html("<table class='list nowrap'>");
 
         if (ctx.qry.path && !strncmp(ctx.qry.path, "heads", 5))
                 cgit_print_branches(0);
         else if (ctx.qry.path && !strncmp(ctx.qry.path, "tags", 4))
                 cgit_print_tags(0);
         else {
                 cgit_print_branches(0);
                 html("<tr class='nohover'><td colspan='4'>&nbsp;</td></tr>");
                 cgit_print_tags(0);
         }
         html("</table>");
 }
diff --git a/ui-shared.c b/ui-shared.c
index 3a9e67b..08ea003 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -1,778 +1,800 @@
 /* ui-shared.c: common web output functions
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "cmd.h"
 #include "html.h"
 
 const char cgit_doctype[] =
 "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\"\n"
 "  \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">\n";
 
 static char *http_date(time_t t)
 {
         static char day[][4] =
                 {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
         static char month[][4] =
                 {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
                  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
         struct tm *tm = gmtime(&t);
         return fmt("%s, %02d %s %04d %02d:%02d:%02d GMT", day[tm->tm_wday],
                    tm->tm_mday, month[tm->tm_mon], 1900+tm->tm_year,
                    tm->tm_hour, tm->tm_min, tm->tm_sec);
 }
 
 void cgit_print_error(char *msg)
 {
         html("<div class='error'>");
         html_txt(msg);
         html("</div>\n");
 }
 
 char *cgit_httpscheme()
 {
         if (ctx.env.https && !strcmp(ctx.env.https, "on"))
                 return "https://";
         else
                 return "http://";
 }
 
 char *cgit_hosturl()
 {
         if (ctx.env.http_host)
                 return ctx.env.http_host;
         if (!ctx.env.server_name)
                 return NULL;
         if (!ctx.env.server_port || atoi(ctx.env.server_port) == 80)
                 return ctx.env.server_name;
         return xstrdup(fmt("%s:%s", ctx.env.server_name, ctx.env.server_port));
 }
 
 char *cgit_rooturl()
 {
         if (ctx.cfg.virtual_root)
                 return fmt("%s/", ctx.cfg.virtual_root);
         else
                 return ctx.cfg.script_name;
 }
 
 char *cgit_repourl(const char *reponame)
 {
         if (ctx.cfg.virtual_root) {
                 return fmt("%s/%s/", ctx.cfg.virtual_root, reponame);
         } else {
                 return fmt("?r=%s", reponame);
         }
 }
 
 char *cgit_fileurl(const char *reponame, const char *pagename,
                    const char *filename, const char *query)
 {
         char *tmp;
         char *delim;
 
         if (ctx.cfg.virtual_root) {
                 tmp = fmt("%s/%s/%s/%s", ctx.cfg.virtual_root, reponame,
                           pagename, (filename ? filename:""));
                 delim = "?";
         } else {
                 tmp = fmt("?url=%s/%s/%s", reponame, pagename,
                           (filename ? filename : ""));
                 delim = "&";
         }
         if (query)
                 tmp = fmt("%s%s%s", tmp, delim, query);
         return tmp;
 }
 
 char *cgit_pageurl(const char *reponame, const char *pagename,
                    const char *query)
 {
         return cgit_fileurl(reponame,pagename,0,query);
 }
 
 const char *cgit_repobasename(const char *reponame)
 {
         /* I assume we don't need to store more than one repo basename */
         static char rvbuf[1024];
         int p;
         const char *rv;
         strncpy(rvbuf,reponame,sizeof(rvbuf));
         if(rvbuf[sizeof(rvbuf)-1])
                 die("cgit_repobasename: truncated repository name '%s'", reponame);
         p = strlen(rvbuf)-1;
         /* strip trailing slashes */
         while(p && rvbuf[p]=='/') rvbuf[p--]=0;
         /* strip trailing .git */
         if(p>=3 && !strncmp(&rvbuf[p-3],".git",4)) {
                 p -= 3; rvbuf[p--] = 0;
         }
         /* strip more trailing slashes if any */
         while( p && rvbuf[p]=='/') rvbuf[p--]=0;
         /* find last slash in the remaining string */
         rv = strrchr(rvbuf,'/');
         if(rv)
                 return ++rv;
         return rvbuf;
 }
 
 char *cgit_currurl()
 {
         if (!ctx.cfg.virtual_root)
                 return ctx.cfg.script_name;
         else if (ctx.qry.page)
                 return fmt("%s/%s/%s/", ctx.cfg.virtual_root, ctx.qry.repo, ctx.qry.page);
         else if (ctx.qry.repo)
                 return fmt("%s/%s/", ctx.cfg.virtual_root, ctx.qry.repo);
         else
                 return fmt("%s/", ctx.cfg.virtual_root);
 }
 
 static void site_url(char *page, char *search, int ofs)
 {
         char *delim = "?";
 
         if (ctx.cfg.virtual_root) {
                 html_attr(ctx.cfg.virtual_root);
                 if (ctx.cfg.virtual_root[strlen(ctx.cfg.virtual_root) - 1] != '/')
                         html("/");
         } else
                 html(ctx.cfg.script_name);
 
         if (page) {
                 htmlf("?p=%s", page);
                 delim = "&";
         }
         if (search) {
                 html(delim);
                 html("q=");
                 html_attr(search);
                 delim = "&";
         }
         if (ofs) {
                 html(delim);
                 htmlf("ofs=%d", ofs);
         }
 }
 
 static void site_link(char *page, char *name, char *title, char *class,
                       char *search, int ofs)
 {
         html("<a");
         if (title) {
                 html(" title='");
                 html_attr(title);
                 html("'");
         }
         if (class) {
                 html(" class='");
                 html_attr(class);
                 html("'");
         }
         html(" href='");
         site_url(page, search, ofs);
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_index_link(char *name, char *title, char *class, char *pattern,
                      int ofs)
 {
         site_link(NULL, name, title, class, pattern, ofs);
 }
 
 static char *repolink(char *title, char *class, char *page, char *head,
                       char *path)
 {
         char *delim = "?";
 
         html("<a");
         if (title) {
                 html(" title='");
                 html_attr(title);
                 html("'");
         }
         if (class) {
                 html(" class='");
                 html_attr(class);
                 html("'");
         }
         html(" href='");
         if (ctx.cfg.virtual_root) {
                 html_url_path(ctx.cfg.virtual_root);
                 if (ctx.cfg.virtual_root[strlen(ctx.cfg.virtual_root) - 1] != '/')
                         html("/");
                 html_url_path(ctx.repo->url);
                 if (ctx.repo->url[strlen(ctx.repo->url) - 1] != '/')
                         html("/");
                 if (page) {
                         html_url_path(page);
                         html("/");
                         if (path)
                                 html_url_path(path);
                 }
         } else {
                 html(ctx.cfg.script_name);
                 html("?url=");
                 html_url_arg(ctx.repo->url);
                 if (ctx.repo->url[strlen(ctx.repo->url) - 1] != '/')
                         html("/");
                 if (page) {
                         html_url_arg(page);
                         html("/");
                         if (path)
                                 html_url_arg(path);
                 }
                 delim = "&amp;";
         }
         if (head && strcmp(head, ctx.repo->defbranch)) {
                 html(delim);
                 html("h=");
                 html_url_arg(head);
                 delim = "&amp;";
         }
         return fmt("%s", delim);
 }
 
 static void reporevlink(char *page, char *name, char *title, char *class,
                         char *head, char *rev, char *path)
 {
         char *delim;
 
         delim = repolink(title, class, page, head, path);
         if (rev && strcmp(rev, ctx.qry.head)) {
                 html(delim);
                 html("id=");
                 html_url_arg(rev);
         }
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_summary_link(char *name, char *title, char *class, char *head)
 {
         reporevlink(NULL, name, title, class, head, NULL, NULL);
 }
 
 void cgit_tag_link(char *name, char *title, char *class, char *head,
                    char *rev)
 {
         reporevlink("tag", name, title, class, head, rev, NULL);
 }
 
 void cgit_tree_link(char *name, char *title, char *class, char *head,
                     char *rev, char *path)
 {
         reporevlink("tree", name, title, class, head, rev, path);
 }
 
 void cgit_plain_link(char *name, char *title, char *class, char *head,
                      char *rev, char *path)
 {
         reporevlink("plain", name, title, class, head, rev, path);
 }
 
 void cgit_log_link(char *name, char *title, char *class, char *head,
                    char *rev, char *path, int ofs, char *grep, char *pattern,
                    int showmsg)
 {
         char *delim;
 
         delim = repolink(title, class, "log", head, path);
         if (rev && strcmp(rev, ctx.qry.head)) {
                 html(delim);
                 html("id=");
                 html_url_arg(rev);
                 delim = "&";
         }
         if (grep && pattern) {
                 html(delim);
                 html("qt=");
                 html_url_arg(grep);
                 delim = "&";
                 html(delim);
                 html("q=");
                 html_url_arg(pattern);
         }
         if (ofs > 0) {
                 html(delim);
                 html("ofs=");
                 htmlf("%d", ofs);
                 delim = "&";
         }
         if (showmsg) {
                 html(delim);
                 html("showmsg=1");
         }
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_commit_link(char *name, char *title, char *class, char *head,
-                      char *rev)
+                      char *rev, int toggle_ssdiff)
 {
         if (strlen(name) > ctx.cfg.max_msg_len && ctx.cfg.max_msg_len >= 15) {
                 name[ctx.cfg.max_msg_len] = '\0';
                 name[ctx.cfg.max_msg_len - 1] = '.';
                 name[ctx.cfg.max_msg_len - 2] = '.';
                 name[ctx.cfg.max_msg_len - 3] = '.';
         }
-        reporevlink("commit", name, title, class, head, rev, NULL);
+
+        char *delim;
+
+        delim = repolink(title, class, "commit", head, NULL);
+        if (rev && strcmp(rev, ctx.qry.head)) {
+                html(delim);
+                html("id=");
+                html_url_arg(rev);
+                delim = "&amp;";
+        }
+        if ((ctx.qry.ssdiff && !toggle_ssdiff) || (!ctx.qry.ssdiff && toggle_ssdiff)) {
+                html(delim);
+                html("ss=1");
+        }
+        html("'>");
+        html_txt(name);
+        html("</a>");
 }
 
 void cgit_refs_link(char *name, char *title, char *class, char *head,
                     char *rev, char *path)
 {
         reporevlink("refs", name, title, class, head, rev, path);
 }
 
 void cgit_snapshot_link(char *name, char *title, char *class, char *head,
                         char *rev, char *archivename)
 {
         reporevlink("snapshot", name, title, class, head, rev, archivename);
 }
 
 void cgit_diff_link(char *name, char *title, char *class, char *head,
-                    char *new_rev, char *old_rev, char *path)
+                    char *new_rev, char *old_rev, char *path,
+                    int toggle_ssdiff)
 {
         char *delim;
 
         delim = repolink(title, class, "diff", head, path);
         if (new_rev && strcmp(new_rev, ctx.qry.head)) {
                 html(delim);
                 html("id=");
                 html_url_arg(new_rev);
                 delim = "&amp;";
         }
         if (old_rev) {
                 html(delim);
                 html("id2=");
                 html_url_arg(old_rev);
+                delim = "&amp;";
+        }
+        if ((ctx.qry.ssdiff && !toggle_ssdiff) || (!ctx.qry.ssdiff && toggle_ssdiff)) {
+                html(delim);
+                html("ss=1");
         }
         html("'>");
         html_txt(name);
         html("</a>");
 }
 
 void cgit_patch_link(char *name, char *title, char *class, char *head,
                      char *rev)
 {
         reporevlink("patch", name, title, class, head, rev, NULL);
 }
 
 void cgit_stats_link(char *name, char *title, char *class, char *head,
                      char *path)
 {
         reporevlink("stats", name, title, class, head, NULL, path);
 }
 
 void cgit_object_link(struct object *obj)
 {
         char *page, *shortrev, *fullrev, *name;
 
         fullrev = sha1_to_hex(obj->sha1);
         shortrev = xstrdup(fullrev);
         shortrev[10] = '\0';
         if (obj->type == OBJ_COMMIT) {
                 cgit_commit_link(fmt("commit %s...", shortrev), NULL, NULL,
-                                 ctx.qry.head, fullrev);
+                                 ctx.qry.head, fullrev, 0);
                 return;
         } else if (obj->type == OBJ_TREE)
                 page = "tree";
         else if (obj->type == OBJ_TAG)
                 page = "tag";
         else
                 page = "blob";
         name = fmt("%s %s...", typename(obj->type), shortrev);
         reporevlink(page, name, NULL, NULL, ctx.qry.head, fullrev, NULL);
 }
 
 void cgit_print_date(time_t secs, char *format, int local_time)
 {
         char buf[64];
         struct tm *time;
 
         if (!secs)
                 return;
         if(local_time)
                 time = localtime(&secs);
         else
                 time = gmtime(&secs);
         strftime(buf, sizeof(buf)-1, format, time);
         html_txt(buf);
 }
 
 void cgit_print_age(time_t t, time_t max_relative, char *format)
 {
         time_t now, secs;
 
         if (!t)
                 return;
         time(&now);
         secs = now - t;
 
         if (secs > max_relative && max_relative >= 0) {
                 cgit_print_date(t, format, ctx.cfg.local_time);
                 return;
         }
 
         if (secs < TM_HOUR * 2) {
                 htmlf("<span class='age-mins'>%.0f min.</span>",
                       secs * 1.0 / TM_MIN);
                 return;
         }
         if (secs < TM_DAY * 2) {
                 htmlf("<span class='age-hours'>%.0f hours</span>",
                       secs * 1.0 / TM_HOUR);
                 return;
         }
         if (secs < TM_WEEK * 2) {
                 htmlf("<span class='age-days'>%.0f days</span>",
                       secs * 1.0 / TM_DAY);
                 return;
         }
         if (secs < TM_MONTH * 2) {
                 htmlf("<span class='age-weeks'>%.0f weeks</span>",
                       secs * 1.0 / TM_WEEK);
                 return;
         }
         if (secs < TM_YEAR * 2) {
                 htmlf("<span class='age-months'>%.0f months</span>",
                       secs * 1.0 / TM_MONTH);
                 return;
         }
         htmlf("<span class='age-years'>%.0f years</span>",
               secs * 1.0 / TM_YEAR);
 }
 
 void cgit_print_http_headers(struct cgit_context *ctx)
 {
         if (ctx->env.no_http && !strcmp(ctx->env.no_http, "1"))
                 return;
 
         if (ctx->page.status)
                 htmlf("Status: %d %s\n", ctx->page.status, ctx->page.statusmsg);
         if (ctx->page.mimetype && ctx->page.charset)
                 htmlf("Content-Type: %s; charset=%s\n", ctx->page.mimetype,
                       ctx->page.charset);
         else if (ctx->page.mimetype)
                 htmlf("Content-Type: %s\n", ctx->page.mimetype);
         if (ctx->page.size)
                 htmlf("Content-Length: %ld\n", ctx->page.size);
         if (ctx->page.filename)
                 htmlf("Content-Disposition: inline; filename=\"%s\"\n",
                       ctx->page.filename);
         htmlf("Last-Modified: %s\n", http_date(ctx->page.modified));
         htmlf("Expires: %s\n", http_date(ctx->page.expires));
         if (ctx->page.etag)
                 htmlf("ETag: \"%s\"\n", ctx->page.etag);
         html("\n");
         if (ctx->env.request_method && !strcmp(ctx->env.request_method, "HEAD"))
                 exit(0);
 }
 
 void cgit_print_docstart(struct cgit_context *ctx)
 {
         if (ctx->cfg.embedded) {
                 if (ctx->cfg.header)
                         html_include(ctx->cfg.header);
                 return;
         }
 
         char *host = cgit_hosturl();
         html(cgit_doctype);
         html("<html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en' lang='en'>\n");
         html("<head>\n");
         html("<title>");
         html_txt(ctx->page.title);
         html("</title>\n");
         htmlf("<meta name='generator' content='cgit %s'/>\n", cgit_version);
         if (ctx->cfg.robots && *ctx->cfg.robots)
                 htmlf("<meta name='robots' content='%s'/>\n", ctx->cfg.robots);
         html("<link rel='stylesheet' type='text/css' href='");
         html_attr(ctx->cfg.css);
         html("'/>\n");
         if (ctx->cfg.favicon) {
                 html("<link rel='shortcut icon' href='");
                 html_attr(ctx->cfg.favicon);
                 html("'/>\n");
         }
         if (host && ctx->repo) {
                 html("<link rel='alternate' title='Atom feed' href='");
                 html(cgit_httpscheme());
                 html_attr(cgit_hosturl());
                 html_attr(cgit_fileurl(ctx->repo->url, "atom", ctx->qry.path,
                                        fmt("h=%s", ctx->qry.head)));
                 html("' type='application/atom+xml'/>\n");
         }
         if (ctx->cfg.head_include)
                 html_include(ctx->cfg.head_include);
         html("</head>\n");
         html("<body>\n");
         if (ctx->cfg.header)
                 html_include(ctx->cfg.header);
 }
 
 void cgit_print_docend()
 {
         html("</div> <!-- class=content -->\n");
         if (ctx.cfg.embedded) {
                 html("</div> <!-- id=cgit -->\n");
                 if (ctx.cfg.footer)
                         html_include(ctx.cfg.footer);
                 return;
         }
         if (ctx.cfg.footer)
                 html_include(ctx.cfg.footer);
         else {
                 htmlf("<div class='footer'>generated  by cgit %s at ",
                         cgit_version);
                 cgit_print_date(time(NULL), FMT_LONGDATE, ctx.cfg.local_time);
                 html("</div>\n");
         }
         html("</div> <!-- id=cgit -->\n");
         html("</body>\n</html>\n");
 }
 
 int print_branch_option(const char *refname, const unsigned char *sha1,
                         int flags, void *cb_data)
 {
         char *name = (char *)refname;
         html_option(name, name, ctx.qry.head);
         return 0;
 }
 
 int print_archive_ref(const char *refname, const unsigned char *sha1,
                        int flags, void *cb_data)
 {
         struct tag *tag;
         struct taginfo *info;
         struct object *obj;
         char buf[256], *url;
         unsigned char fileid[20];
         int *header = (int *)cb_data;
 
         if (prefixcmp(refname, "refs/archives"))
                 return 0;
         strncpy(buf, refname+14, sizeof(buf));
         obj = parse_object(sha1);
         if (!obj)
                 return 1;
         if (obj->type == OBJ_TAG) {
                 tag = lookup_tag(sha1);
                 if (!tag || parse_tag(tag) || !(info = cgit_parse_tag(tag)))
                         return 0;
                 hashcpy(fileid, tag->tagged->sha1);
         } else if (obj->type != OBJ_BLOB) {
                 return 0;
         } else {
                 hashcpy(fileid, sha1);
         }
         if (!*header) {
                 html("<h1>download</h1>\n");
                 *header = 1;
         }
         url = cgit_pageurl(ctx.qry.repo, "blob",
                            fmt("id=%s&amp;path=%s", sha1_to_hex(fileid),
                                buf));
         html_link_open(url, NULL, "menu");
         html_txt(strlpart(buf, 20));
         html_link_close();
         return 0;
 }
 
 void cgit_add_hidden_formfields(int incl_head, int incl_search, char *page)
 {
         char *url;
 
         if (!ctx.cfg.virtual_root) {
                 url = fmt("%s/%s", ctx.qry.repo, page);
                 if (ctx.qry.path)
                         url = fmt("%s/%s", url, ctx.qry.path);
                 html_hidden("url", url);
         }
 
         if (incl_head && ctx.qry.head && ctx.repo->defbranch &&
             strcmp(ctx.qry.head, ctx.repo->defbranch))
                 html_hidden("h", ctx.qry.head);
 
         if (ctx.qry.sha1)
                 html_hidden("id", ctx.qry.sha1);
         if (ctx.qry.sha2)
                 html_hidden("id2", ctx.qry.sha2);
         if (ctx.qry.showmsg)
                 html_hidden("showmsg", "1");
 
         if (incl_search) {
                 if (ctx.qry.grep)
                         html_hidden("qt", ctx.qry.grep);
                 if (ctx.qry.search)
                         html_hidden("q", ctx.qry.search);
         }
 }
 
 const char *fallback_cmd = "repolist";
 
 char *hc(struct cgit_cmd *cmd, const char *page)
 {
         return (strcmp(cmd ? cmd->name : fallback_cmd, page) ? NULL : "active");
 }
 
 static void print_header(struct cgit_context *ctx)
 {
         html("<table id='header'>\n");
         html("<tr>\n");
 
         if (ctx->cfg.logo && ctx->cfg.logo[0] != 0) {
                 html("<td class='logo' rowspan='2'><a href='");
                 if (ctx->cfg.logo_link)
                         html_attr(ctx->cfg.logo_link);
                 else
                         html_attr(cgit_rooturl());
                 html("'><img src='");
                 html_attr(ctx->cfg.logo);
                 html("' alt='cgit logo'/></a></td>\n");
         }
 
         html("<td class='main'>");
         if (ctx->repo) {
                 cgit_index_link("index", NULL, NULL, NULL, 0);
                 html(" : ");
                 cgit_summary_link(ctx->repo->name, ctx->repo->name, NULL, NULL);
                 html("</td><td class='form'>");
                 html("<form method='get' action=''>\n");
                 cgit_add_hidden_formfields(0, 1, ctx->qry.page);
                 html("<select name='h' onchange='this.form.submit();'>\n");
                 for_each_branch_ref(print_branch_option, ctx->qry.head);
                 html("</select> ");
                 html("<input type='submit' name='' value='switch'/>");
                 html("</form>");
         } else
                 html_txt(ctx->cfg.root_title);
         html("</td></tr>\n");
 
         html("<tr><td class='sub'>");
         if (ctx->repo) {
                 html_txt(ctx->repo->desc);
                 html("</td><td class='sub right'>");
                 html_txt(ctx->repo->owner);
         } else {
                 if (ctx->cfg.root_desc)
                         html_txt(ctx->cfg.root_desc);
                 else if (ctx->cfg.index_info)
                         html_include(ctx->cfg.index_info);
         }
         html("</td></tr></table>\n");
 }
 
 void cgit_print_pageheader(struct cgit_context *ctx)
 {
         struct cgit_cmd *cmd = cgit_get_cmd(ctx);
 
         if (!cmd && ctx->repo)
                 fallback_cmd = "summary";
 
         html("<div id='cgit'>");
         if (!ctx->cfg.noheader)
                 print_header(ctx);
 
         html("<table class='tabs'><tr><td>\n");
         if (ctx->repo) {
                 cgit_summary_link("summary", NULL, hc(cmd, "summary"),
                                   ctx->qry.head);
                 cgit_refs_link("refs", NULL, hc(cmd, "refs"), ctx->qry.head,
                                ctx->qry.sha1, NULL);
                 cgit_log_link("log", NULL, hc(cmd, "log"), ctx->qry.head,
                               NULL, NULL, 0, NULL, NULL, ctx->qry.showmsg);
                 cgit_tree_link("tree", NULL, hc(cmd, "tree"), ctx->qry.head,
                                ctx->qry.sha1, NULL);
                 cgit_commit_link("commit", NULL, hc(cmd, "commit"),
-                                 ctx->qry.head, ctx->qry.sha1);
+                                 ctx->qry.head, ctx->qry.sha1, 0);
                 cgit_diff_link("diff", NULL, hc(cmd, "diff"), ctx->qry.head,
-                               ctx->qry.sha1, ctx->qry.sha2, NULL);
+                               ctx->qry.sha1, ctx->qry.sha2, NULL, 0);
                 if (ctx->repo->max_stats)
                         cgit_stats_link("stats", NULL, hc(cmd, "stats"),
                                         ctx->qry.head, NULL);
                 if (ctx->repo->readme)
                         reporevlink("about", "about", NULL,
                                     hc(cmd, "about"), ctx->qry.head, NULL,
                                     NULL);
                 html("</td><td class='form'>");
                 html("<form class='right' method='get' action='");
                 if (ctx->cfg.virtual_root)
                         html_url_path(cgit_fileurl(ctx->qry.repo, "log",
                                                    ctx->qry.path, NULL));
                 html("'>\n");
                 cgit_add_hidden_formfields(1, 0, "log");
                 html("<select name='qt'>\n");
                 html_option("grep", "log msg", ctx->qry.grep);
                 html_option("author", "author", ctx->qry.grep);
                 html_option("committer", "committer", ctx->qry.grep);
                 html("</select>\n");
                 html("<input class='txt' type='text' size='10' name='q' value='");
                 html_attr(ctx->qry.search);
                 html("'/>\n");
                 html("<input type='submit' value='search'/>\n");
                 html("</form>\n");
         } else {
                 site_link(NULL, "index", NULL, hc(cmd, "repolist"), NULL, 0);
                 if (ctx->cfg.root_readme)
                         site_link("about", "about", NULL, hc(cmd, "about"),
                                   NULL, 0);
                 html("</td><td class='form'>");
                 html("<form method='get' action='");
                 html_attr(cgit_rooturl());
                 html("'>\n");
                 html("<input type='text' name='q' size='10' value='");
                 html_attr(ctx->qry.search);
                 html("'/>\n");
                 html("<input type='submit' value='search'/>\n");
                 html("</form>");
         }
         html("</td></tr></table>\n");
         html("<div class='content'>");
 }
 
 void cgit_print_filemode(unsigned short mode)
 {
         if (S_ISDIR(mode))
                 html("d");
         else if (S_ISLNK(mode))
                 html("l");
         else if (S_ISGITLINK(mode))
                 html("m");
         else
                 html("-");
         html_fileperm(mode >> 6);
         html_fileperm(mode >> 3);
         html_fileperm(mode);
 }
 
 void cgit_print_snapshot_links(const char *repo, const char *head,
                                const char *hex, int snapshots)
 {
         const struct cgit_snapshot_format* f;
         char *prefix;
             char *filename;
         unsigned char sha1[20];
 
         if (get_sha1(fmt("refs/tags/%s", hex), sha1) == 0 &&
             (hex[0] == 'v' || hex[0] == 'V') && isdigit(hex[1]))
                 hex++;
         prefix = xstrdup(fmt("%s-%s", cgit_repobasename(repo), hex));
         for (f = cgit_snapshot_formats; f->suffix; f++) {
                 if (!(snapshots & f->bit))
                         continue;
                 filename = fmt("%s%s", prefix, f->suffix);
                 cgit_snapshot_link(filename, NULL, NULL, NULL, NULL, filename);
                 html("<br/>");
         }
 }
diff --git a/ui-shared.h b/ui-shared.h
index b12aa89..9ebc1f9 100644
--- a/ui-shared.h
+++ b/ui-shared.h
@@ -1,51 +1,52 @@
 #ifndef UI_SHARED_H
 #define UI_SHARED_H
 
 extern char *cgit_httpscheme();
 extern char *cgit_hosturl();
 extern char *cgit_rooturl();
 extern char *cgit_repourl(const char *reponame);
 extern char *cgit_fileurl(const char *reponame, const char *pagename,
                           const char *filename, const char *query);
 extern char *cgit_pageurl(const char *reponame, const char *pagename,
                           const char *query);
 
 extern void cgit_index_link(char *name, char *title, char *class,
                             char *pattern, int ofs);
 extern void cgit_summary_link(char *name, char *title, char *class, char *head);
 extern void cgit_tag_link(char *name, char *title, char *class, char *head,
                           char *rev);
 extern void cgit_tree_link(char *name, char *title, char *class, char *head,
                            char *rev, char *path);
 extern void cgit_plain_link(char *name, char *title, char *class, char *head,
                             char *rev, char *path);
 extern void cgit_log_link(char *name, char *title, char *class, char *head,
                           char *rev, char *path, int ofs, char *grep,
                           char *pattern, int showmsg);
 extern void cgit_commit_link(char *name, char *title, char *class, char *head,
-                             char *rev);
+                             char *rev, int toggle_ssdiff);
 extern void cgit_patch_link(char *name, char *title, char *class, char *head,
                             char *rev);
 extern void cgit_refs_link(char *name, char *title, char *class, char *head,
                            char *rev, char *path);
 extern void cgit_snapshot_link(char *name, char *title, char *class,
                                char *head, char *rev, char *archivename);
 extern void cgit_diff_link(char *name, char *title, char *class, char *head,
-                           char *new_rev, char *old_rev, char *path);
+                           char *new_rev, char *old_rev, char *path,
+                           int toggle_ssdiff);
 extern void cgit_stats_link(char *name, char *title, char *class, char *head,
                             char *path);
 extern void cgit_object_link(struct object *obj);
 
 extern void cgit_print_error(char *msg);
 extern void cgit_print_date(time_t secs, char *format, int local_time);
 extern void cgit_print_age(time_t t, time_t max_relative, char *format);
 extern void cgit_print_http_headers(struct cgit_context *ctx);
 extern void cgit_print_docstart(struct cgit_context *ctx);
 extern void cgit_print_docend();
 extern void cgit_print_pageheader(struct cgit_context *ctx);
 extern void cgit_print_filemode(unsigned short mode);
 extern void cgit_print_snapshot_links(const char *repo, const char *head,
                                       const char *hex, int snapshots);
 extern void cgit_add_hidden_formfields(int incl_head, int incl_search,
                                        char *page);
 #endif /* UI_SHARED_H */
diff --git a/ui-ssdiff.c b/ui-ssdiff.c
new file mode 100644
index 0000000..408e620
--- a/dev/null
+++ b/ui-ssdiff.c
@@ -0,0 +1,369 @@
+#include "cgit.h"
+#include "html.h"
+#include "ui-shared.h"
+
+extern int use_ssdiff;
+
+static int current_old_line, current_new_line;
+
+struct deferred_lines {
+        int line_no;
+        char *line;
+        struct deferred_lines *next;
+};
+
+static struct deferred_lines *deferred_old, *deferred_old_last;
+static struct deferred_lines *deferred_new, *deferred_new_last;
+
+static char *longest_common_subsequence(char *A, char *B)
+{
+        int i, j, ri;
+        int m = strlen(A);
+        int n = strlen(B);
+        int L[m + 1][n + 1];
+        int tmp1, tmp2;
+        int lcs_length;
+        char *result;
+
+        for (i = m; i >= 0; i--) {
+                for (j = n; j >= 0; j--) {
+                        if (A[i] == '\0' || B[j] == '\0') {
+                                L[i][j] = 0;
+                        } else if (A[i] == B[j]) {
+                                L[i][j] = 1 + L[i + 1][j + 1];
+                        } else {
+                                tmp1 = L[i + 1][j];
+                                tmp2 = L[i][j + 1];
+                                L[i][j] = (tmp1 > tmp2 ? tmp1 : tmp2);
+                        }
+                }
+        }
+
+        lcs_length = L[0][0];
+        result = xmalloc(lcs_length + 2);
+        memset(result, 0, sizeof(*result) * (lcs_length + 2));
+
+        ri = 0;
+        i = 0;
+        j = 0;
+        while (i < m && j < n) {
+                if (A[i] == B[j]) {
+                        result[ri] = A[i];
+                        ri += 1;
+                        i += 1;
+                        j += 1;
+                } else if (L[i + 1][j] >= L[i][j + 1]) {
+                        i += 1;
+                } else {
+                        j += 1;
+                }
+        }
+        return result;
+}
+
+static int line_from_hunk(char *line, char type)
+{
+        char *buf1, *buf2;
+        int len;
+
+        buf1 = strchr(line, type);
+        if (buf1 == NULL)
+                return 0;
+        buf1 += 1;
+        buf2 = strchr(buf1, ',');
+        if (buf2 == NULL)
+                return 0;
+        len = buf2 - buf1;
+        buf2 = xmalloc(len + 1);
+        strncpy(buf2, buf1, len);
+        buf2[len] = '\0';
+        int res = atoi(buf2);
+        free(buf2);
+        return res;
+}
+
+static char *replace_tabs(char *line)
+{
+        char *prev_buf = line;
+        char *cur_buf;
+        int linelen = strlen(line);
+        int n_tabs = 0;
+        int i;
+        char *result;
+        char *spaces = "        ";
+
+        if (linelen == 0) {
+                result = xmalloc(1);
+                result[0] = '\0';
+                return result;
+        }
+
+        for (i = 0; i < linelen; i++)
+                if (line[i] == '\t')
+                        n_tabs += 1;
+        result = xmalloc(linelen + n_tabs * 8 + 1);
+        result[0] = '\0';
+
+        while (1) {
+                cur_buf = strchr(prev_buf, '\t');
+                if (!cur_buf) {
+                        strcat(result, prev_buf);
+                        break;
+                } else {
+                        strcat(result, " ");
+                        strncat(result, spaces, 8 - (strlen(result) % 8));
+                        strncat(result, prev_buf, cur_buf - prev_buf);
+                }
+                prev_buf = cur_buf + 1;
+        }
+        return result;
+}
+
+static int calc_deferred_lines(struct deferred_lines *start)
+{
+        struct deferred_lines *item = start;
+        int result = 0;
+        while (item) {
+                result += 1;
+                item = item->next;
+        }
+        return result;
+}
+
+static void deferred_old_add(char *line, int line_no)
+{
+        struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
+        item->line = xstrdup(line);
+        item->line_no = line_no;
+        item->next = NULL;
+        if (deferred_old) {
+                deferred_old_last->next = item;
+                deferred_old_last = item;
+        } else {
+                deferred_old = deferred_old_last = item;
+        }
+}
+
+static void deferred_new_add(char *line, int line_no)
+{
+        struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
+        item->line = xstrdup(line);
+        item->line_no = line_no;
+        item->next = NULL;
+        if (deferred_new) {
+                deferred_new_last->next = item;
+                deferred_new_last = item;
+        } else {
+                deferred_new = deferred_new_last = item;
+        }
+}
+
+static void print_part_with_lcs(char *class, char *line, char *lcs)
+{
+        int line_len = strlen(line);
+        int i, j;
+        char c[2] = " ";
+        int same = 1;
+
+        j = 0;
+        for (i = 0; i < line_len; i++) {
+                c[0] = line[i];
+                if (same) {
+                        if (line[i] == lcs[j])
+                                j += 1;
+                        else {
+                                same = 0;
+                                htmlf("<span class='%s'>", class);
+                        }
+                } else if (line[i] == lcs[j]) {
+                        same = 1;
+                        htmlf("</span>");
+                        j += 1;
+                }
+                html_txt(c);
+        }
+}
+
+static void print_ssdiff_line(char *class,
+                              int old_line_no,
+                              char *old_line,
+                              int new_line_no,
+                              char *new_line, int individual_chars)
+{
+        char *lcs = NULL;
+        if (old_line)
+                old_line = replace_tabs(old_line + 1);
+        if (new_line)
+                new_line = replace_tabs(new_line + 1);
+        if (individual_chars && old_line && new_line)
+                lcs = longest_common_subsequence(old_line, new_line);
+        html("<tr>");
+        if (old_line_no > 0)
+                htmlf("<td class='lineno'>%d</td><td class='%s'>",
+                      old_line_no, class);
+        else if (old_line)
+                htmlf("<td class='lineno'></td><td class='%s'>", class);
+        else
+                htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
+        if (old_line) {
+                if (lcs)
+                        print_part_with_lcs("del", old_line, lcs);
+                else
+                        html_txt(old_line);
+        }
+
+        html("</td>");
+        if (new_line_no > 0)
+                htmlf("<td class='lineno'>%d</td><td class='%s'>",
+                      new_line_no, class);
+        else if (new_line)
+                htmlf("<td class='lineno'></td><td class='%s'>", class);
+        else
+                htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
+        if (new_line) {
+                if (lcs)
+                        print_part_with_lcs("add", new_line, lcs);
+                else
+                        html_txt(new_line);
+        }
+
+        html("</td></tr>");
+        if (lcs)
+                free(lcs);
+        if (new_line)
+                free(new_line);
+        if (old_line)
+                free(old_line);
+}
+
+static void print_deferred_old_lines()
+{
+        struct deferred_lines *iter_old, *tmp;
+        iter_old = deferred_old;
+        while (iter_old) {
+                print_ssdiff_line("del", iter_old->line_no,
+                                  iter_old->line, -1, NULL, 0);
+                tmp = iter_old->next;
+                free(iter_old);
+                iter_old = tmp;
+        }
+}
+
+static void print_deferred_new_lines()
+{
+        struct deferred_lines *iter_new, *tmp;
+        iter_new = deferred_new;
+        while (iter_new) {
+                print_ssdiff_line("add", -1, NULL,
+                                  iter_new->line_no, iter_new->line, 0);
+                tmp = iter_new->next;
+                free(iter_new);
+                iter_new = tmp;
+        }
+}
+
+static void print_deferred_changed_lines()
+{
+        struct deferred_lines *iter_old, *iter_new, *tmp;
+        int n_old_lines = calc_deferred_lines(deferred_old);
+        int n_new_lines = calc_deferred_lines(deferred_new);
+        int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
+
+        iter_old = deferred_old;
+        iter_new = deferred_new;
+        while (iter_old || iter_new) {
+                if (iter_old && iter_new)
+                        print_ssdiff_line("changed", iter_old->line_no,
+                                          iter_old->line,
+                                          iter_new->line_no, iter_new->line,
+                                          individual_chars);
+                else if (iter_old)
+                        print_ssdiff_line("changed", iter_old->line_no,
+                                          iter_old->line, -1, NULL, 0);
+                else if (iter_new)
+                        print_ssdiff_line("changed", -1, NULL,
+                                          iter_new->line_no, iter_new->line, 0);
+                if (iter_old) {
+                        tmp = iter_old->next;
+                        free(iter_old);
+                        iter_old = tmp;
+                }
+
+                if (iter_new) {
+                        tmp = iter_new->next;
+                        free(iter_new);
+                        iter_new = tmp;
+                }
+        }
+}
+
+void cgit_ssdiff_print_deferred_lines()
+{
+        if (!deferred_old && !deferred_new)
+                return;
+        if (deferred_old && !deferred_new)
+                print_deferred_old_lines();
+        else if (!deferred_old && deferred_new)
+                print_deferred_new_lines();
+        else
+                print_deferred_changed_lines();
+        deferred_old = deferred_old_last = NULL;
+        deferred_new = deferred_new_last = NULL;
+}
+
+/*
+ * print a single line returned from xdiff
+ */
+void cgit_ssdiff_line_cb(char *line, int len)
+{
+        char c = line[len - 1];
+        line[len - 1] = '\0';
+        if (line[0] == '@') {
+                current_old_line = line_from_hunk(line, '-');
+                current_new_line = line_from_hunk(line, '+');
+        }
+
+        if (line[0] == ' ') {
+                if (deferred_old || deferred_new)
+                        cgit_ssdiff_print_deferred_lines();
+                print_ssdiff_line("ctx", current_old_line, line,
+                                  current_new_line, line, 0);
+                current_old_line += 1;
+                current_new_line += 1;
+        } else if (line[0] == '+') {
+                deferred_new_add(line, current_new_line);
+                current_new_line += 1;
+        } else if (line[0] == '-') {
+                deferred_old_add(line, current_old_line);
+                current_old_line += 1;
+        } else if (line[0] == '@') {
+                html("<tr><td colspan='4' class='hunk'>");
+                html_txt(line);
+                html("</td></tr>");
+        } else {
+                html("<tr><td colspan='4' class='ctx'>");
+                html_txt(line);
+                html("</td></tr>");
+        }
+        line[len - 1] = c;
+}
+
+void cgit_ssdiff_header_begin()
+{
+        current_old_line = -1;
+        current_new_line = -1;
+        html("<tr><td class='space' colspan='4'><div></div></td></tr>");
+        html("<tr><td class='head' colspan='4'>");
+}
+
+void cgit_ssdiff_header_end()
+{
+        html("</td><tr>");
+}
+
+void cgit_ssdiff_footer()
+{
+        if (deferred_old || deferred_new)
+                cgit_ssdiff_print_deferred_lines();
+        html("<tr><td class='foot' colspan='4'></td></tr>");
+}
diff --git a/ui-ssdiff.h b/ui-ssdiff.h
new file mode 100644
index 0000000..64b4b12
--- a/dev/null
+++ b/ui-ssdiff.h
@@ -0,0 +1,13 @@
+#ifndef UI_SSDIFF_H
+#define UI_SSDIFF_H
+
+extern void cgit_ssdiff_print_deferred_lines();
+
+extern void cgit_ssdiff_line_cb(char *line, int len);
+
+extern void cgit_ssdiff_header_begin();
+extern void cgit_ssdiff_header_end();
+
+extern void cgit_ssdiff_footer();
+
+#endif /* UI_SSDIFF_H */