Enable default value for head parameter

Pages which expect head to be specified in the querystring can now be
given a default value, configurable per repository (via repo.defbranch,
which defaults to "master").

Currently, only the log page actually works without parameters, but the
defbranch is bound to be exploited.

This also removes some dead code from shared.c

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

3 files changed, 7 insertions, 14 deletions

diff --git a/cgit.c b/cgit.c
index 3c11ff0..b282a67 100644
--- a/cgit.c
+++ b/cgit.c
@@ -1,262 +1,265 @@
 /* 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"
 
 const char cgit_version[] = CGIT_VERSION;
 
 
 static struct repoinfo *cgit_get_repoinfo(char *url)
 {
         int i;
         struct repoinfo *repo;
 
         for (i=0; i<cgit_repolist.count; i++) {
                 repo = &cgit_repolist.repos[i];
                 if (!strcmp(repo->url, url))
                         return repo;
         }
         return NULL;
 }
 
 
 static int cgit_prepare_cache(struct cacheitem *item)
 {
         if (!cgit_query_repo) {
                 item->name = xstrdup(fmt("%s/index.html", cgit_cache_root));
                 item->ttl = cgit_cache_root_ttl;
                 return 1;
         }
         cgit_repo = cgit_get_repoinfo(cgit_query_repo);
         if (!cgit_repo) {
                 char *title = fmt("%s - %s", cgit_root_title, "Bad request");
                 cgit_print_docstart(title, item);
                 cgit_print_pageheader(title, 0);
                 cgit_print_error(fmt("Unknown repo: %s", cgit_query_repo));
                 cgit_print_docend();
                 return 0;
         }
 
         if (!cgit_query_page) {
                 item->name = xstrdup(fmt("%s/%s/index.html", cgit_cache_root,
                            cgit_repo->url));
                 item->ttl = cgit_cache_repo_ttl;
         } else {
                 item->name = xstrdup(fmt("%s/%s/%s/%s.html", cgit_cache_root,
                            cgit_repo->url, cgit_query_page,
                            cache_safe_filename(cgit_querystring)));
                 if (cgit_query_has_symref)
                         item->ttl = cgit_cache_dynamic_ttl;
                 else if (cgit_query_has_sha1)
                         item->ttl = cgit_cache_static_ttl;
                 else
                         item->ttl = cgit_cache_repo_ttl;
         }
         return 1;
 }
 
 static void cgit_print_repo_page(struct cacheitem *item)
 {
         char *title;
         int show_search;
 
+        if (!cgit_query_head)
+                cgit_query_head = cgit_repo->defbranch;
+
         if (chdir(cgit_repo->path)) {
                 title = fmt("%s - %s", cgit_root_title, "Bad request");
                 cgit_print_docstart(title, item);
                 cgit_print_pageheader(title, 0);
                 cgit_print_error(fmt("Unable to scan repository: %s",
                                      strerror(errno)));
                 cgit_print_docend();
                 return;
         }
 
         title = fmt("%s - %s", cgit_repo->name, cgit_repo->desc);
         show_search = 0;
         setenv("GIT_DIR", cgit_repo->path, 1);
 
         if (cgit_query_page) {
             if (cgit_repo->snapshots && !strcmp(cgit_query_page, "snapshot")) {
                 cgit_print_snapshot(item, cgit_query_sha1, "zip",
                                     cgit_repo->url, cgit_query_name);
                 return;
             }
             if (!strcmp(cgit_query_page, "blob")) {
                     cgit_print_blob(item, cgit_query_sha1, cgit_query_path);
                     return;
             }
         }
 
         if (cgit_query_page && !strcmp(cgit_query_page, "log"))
                 show_search = 1;
 
         cgit_print_docstart(title, item);
 
 
         if (!cgit_query_page) {
                 cgit_print_pageheader("summary", show_search);
                 cgit_print_summary();
                 cgit_print_docend();
                 return;
         }
 
         cgit_print_pageheader(cgit_query_page, show_search);
 
         if (!strcmp(cgit_query_page, "log")) {
                 cgit_print_log(cgit_query_head, cgit_query_ofs,
                                cgit_max_commit_count, cgit_query_search,
                                cgit_query_path);
         } else if (!strcmp(cgit_query_page, "tree")) {
                 cgit_print_tree(cgit_query_head, cgit_query_sha1, cgit_query_path);
         } else if (!strcmp(cgit_query_page, "commit")) {
                 cgit_print_commit(cgit_query_sha1);
         } else if (!strcmp(cgit_query_page, "view")) {
                 cgit_print_view(cgit_query_sha1, cgit_query_path);
         } else if (!strcmp(cgit_query_page, "diff")) {
                 cgit_print_diff(cgit_query_sha1, cgit_query_sha2, cgit_query_path);
         } else {
                 cgit_print_error("Invalid request");
         }
         cgit_print_docend();
 }
 
 static void cgit_fill_cache(struct cacheitem *item, int use_cache)
 {
         static char buf[PATH_MAX];
         int stdout2;
 
         getcwd(buf, sizeof(buf));
         item->st.st_mtime = time(NULL);
 
         if (use_cache) {
                 stdout2 = chk_positive(dup(STDOUT_FILENO),
                                        "Preserving STDOUT");
                 chk_zero(close(STDOUT_FILENO), "Closing STDOUT");
                 chk_positive(dup2(item->fd, STDOUT_FILENO), "Dup2(cachefile)");
         }
 
         if (cgit_query_repo)
                 cgit_print_repo_page(item);
         else
                 cgit_print_repolist(item);
 
         if (use_cache) {
                 chk_zero(close(STDOUT_FILENO), "Close redirected STDOUT");
                 chk_positive(dup2(stdout2, STDOUT_FILENO),
                              "Restoring original STDOUT");
                 chk_zero(close(stdout2), "Closing temporary STDOUT");
         }
 
         chdir(buf);
 }
 
 static void cgit_check_cache(struct cacheitem *item)
 {
         int i = 0;
 
  top:
         if (++i > cgit_max_lock_attempts) {
                 die("cgit_refresh_cache: unable to lock %s: %s",
                     item->name, strerror(errno));
         }
         if (!cache_exist(item)) {
                 if (!cache_lock(item)) {
                         sleep(1);
                         goto top;
                 }
                 if (!cache_exist(item)) {
                         cgit_fill_cache(item, 1);
                         cache_unlock(item);
                 } else {
                         cache_cancel_lock(item);
                 }
         } else if (cache_expired(item) && cache_lock(item)) {
                 if (cache_expired(item)) {
                         cgit_fill_cache(item, 1);
                         cache_unlock(item);
                 } else {
                         cache_cancel_lock(item);
                 }
         }
 }
 
 static void cgit_print_cache(struct cacheitem *item)
 {
         static char buf[4096];
         ssize_t i;
 
         int fd = open(item->name, O_RDONLY);
         if (fd<0)
                 die("Unable to open cached file %s", item->name);
 
         while((i=read(fd, buf, sizeof(buf))) > 0)
                 write(STDOUT_FILENO, buf, i);
 
         close(fd);
 }
 
 static void cgit_parse_args(int argc, const char **argv)
 {
         int i;
 
         for (i = 1; i < argc; i++) {
                 if (!strncmp(argv[i], "--cache=", 8)) {
                         cgit_cache_root = xstrdup(argv[i]+8);
                 }
                 if (!strcmp(argv[i], "--nocache")) {
                         cgit_nocache = 1;
                 }
                 if (!strncmp(argv[i], "--query=", 8)) {
                         cgit_querystring = xstrdup(argv[i]+8);
                 }
                 if (!strncmp(argv[i], "--repo=", 7)) {
                         cgit_query_repo = xstrdup(argv[i]+7);
                 }
                 if (!strncmp(argv[i], "--page=", 7)) {
                         cgit_query_page = xstrdup(argv[i]+7);
                 }
                 if (!strncmp(argv[i], "--head=", 7)) {
                         cgit_query_head = xstrdup(argv[i]+7);
                         cgit_query_has_symref = 1;
                 }
                 if (!strncmp(argv[i], "--sha1=", 7)) {
                         cgit_query_sha1 = xstrdup(argv[i]+7);
                         cgit_query_has_sha1 = 1;
                 }
                 if (!strncmp(argv[i], "--ofs=", 6)) {
                         cgit_query_ofs = atoi(argv[i]+6);
                 }
         }
 }
 
 int main(int argc, const char **argv)
 {
         struct cacheitem item;
 
         htmlfd = STDOUT_FILENO;
         item.st.st_mtime = time(NULL);
         cgit_repolist.length = 0;
         cgit_repolist.count = 0;
         cgit_repolist.repos = NULL;
 
         cgit_read_config(CGIT_CONFIG, cgit_global_config_cb);
         if (getenv("SCRIPT_NAME"))
                 cgit_script_name = xstrdup(getenv("SCRIPT_NAME"));
         if (getenv("QUERY_STRING"))
                 cgit_querystring = xstrdup(getenv("QUERY_STRING"));
         cgit_parse_args(argc, argv);
         cgit_parse_query(cgit_querystring, cgit_querystring_cb);
         if (!cgit_prepare_cache(&item))
                 return 0;
         if (cgit_nocache) {
                 cgit_fill_cache(&item, 0);
         } else {
                 cgit_check_cache(&item);
                 cgit_print_cache(&item);
         }
         return 0;
 }
diff --git a/cgit.h b/cgit.h
index f5906ad..ac710a6 100644
--- a/cgit.h
+++ b/cgit.h
@@ -1,183 +1,184 @@
 #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 <xdiff/xdiff.h>
 
 
 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 cacheitem {
         char *name;
         struct stat st;
         int ttl;
         int fd;
 };
 
 struct repoinfo {
         char *url;
         char *name;
         char *path;
         char *desc;
         char *owner;
+        char *defbranch;
         char *module_link;
         int snapshots;
 };
 
 struct repolist {
         int length;
         int count;
         struct repoinfo *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;
 };
 
 struct taginfo {
         char *tagger;
         char *tagger_email;
         int tagger_date;
         char *msg;
 };
 
 extern const char cgit_version[];
 
 extern struct repolist cgit_repolist;
 extern struct repoinfo *cgit_repo;
 
 extern char *cgit_root_title;
 extern char *cgit_css;
 extern char *cgit_logo;
 extern char *cgit_logo_link;
 extern char *cgit_module_link;
 extern char *cgit_virtual_root;
 extern char *cgit_script_name;
 extern char *cgit_cache_root;
 
 extern int cgit_nocache;
 extern int cgit_snapshots;
 extern int cgit_max_lock_attempts;
 extern int cgit_cache_root_ttl;
 extern int cgit_cache_repo_ttl;
 extern int cgit_cache_dynamic_ttl;
 extern int cgit_cache_static_ttl;
 extern int cgit_cache_max_create_time;
 
 extern int cgit_max_msg_len;
 extern int cgit_max_commit_count;
 
 extern char *cgit_repo_name;
 extern char *cgit_repo_desc;
 extern char *cgit_repo_owner;
 
 extern int cgit_query_has_symref;
 extern int cgit_query_has_sha1;
 
 extern char *cgit_querystring;
 extern char *cgit_query_repo;
 extern char *cgit_query_page;
 extern char *cgit_query_search;
 extern char *cgit_query_head;
 extern char *cgit_query_sha1;
 extern char *cgit_query_sha2;
 extern char *cgit_query_path;
 extern char *cgit_query_name;
 extern int   cgit_query_ofs;
 
 extern int htmlfd;
 
 extern void cgit_global_config_cb(const char *name, const char *value);
 extern void cgit_repo_config_cb(const char *name, const char *value);
 extern void cgit_querystring_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 hextoint(char c);
 
 extern void *cgit_free_commitinfo(struct commitinfo *info);
 
 extern int cgit_diff_files(const unsigned char *old_sha1,
                            const unsigned char *new_sha1,
                            linediff_fn fn);
 
 extern void cgit_diff_tree(const unsigned char *old_sha1,
                            const unsigned char *new_sha1,
                            filepair_fn fn);
 
 extern void cgit_diff_commit(struct commit *commit, filepair_fn fn);
 
 extern char *fmt(const char *format,...);
 
 extern void html(const char *txt);
 extern void htmlf(const char *format,...);
 extern void html_txt(char *txt);
 extern void html_ntxt(int len, char *txt);
 extern void html_attr(char *txt);
 extern void html_hidden(char *name, char *value);
 extern void html_link_open(char *url, char *title, char *class);
 extern void html_link_close(void);
 extern void html_filemode(unsigned short mode);
 
 extern int cgit_read_config(const char *filename, configfn fn);
 extern int cgit_parse_query(char *txt, configfn fn);
 extern struct commitinfo *cgit_parse_commit(struct commit *commit);
 extern struct taginfo *cgit_parse_tag(struct tag *tag);
 
 extern char *cache_safe_filename(const char *unsafe);
 extern int cache_lock(struct cacheitem *item);
 extern int cache_unlock(struct cacheitem *item);
 extern int cache_cancel_lock(struct cacheitem *item);
 extern int cache_exist(struct cacheitem *item);
 extern int cache_expired(struct cacheitem *item);
 
 extern char *cgit_repourl(const char *reponame);
 extern char *cgit_pageurl(const char *reponame, const char *pagename, 
                           const char *query);
 
 extern void cgit_print_error(char *msg);
 extern void cgit_print_date(unsigned long secs);
 extern void cgit_print_docstart(char *title, struct cacheitem *item);
 extern void cgit_print_docend();
 extern void cgit_print_pageheader(char *title, int show_search);
 extern void cgit_print_snapshot_start(const char *mimetype, 
                                       const char *filename, 
                                       struct cacheitem *item);
 
 extern void cgit_print_repolist(struct cacheitem *item);
 extern void cgit_print_summary();
 extern void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *path);
 extern void cgit_print_view(const char *hex, char *path);
 extern void cgit_print_blob(struct cacheitem *item, const char *hex, char *path);
 extern void cgit_print_tree(const char *rev, const char *hex, char *path);
 extern void cgit_print_commit(const char *hex);
 extern void cgit_print_diff(const char *old_hex, const char *new_hex, char *path);
 extern void cgit_print_snapshot(struct cacheitem *item, const char *hex, 
                                 const char *format, const char *prefix,
                                 const char *filename);
 
 #endif /* CGIT_H */
diff --git a/shared.c b/shared.c
index 8505397..a1e1acd 100644
--- a/shared.c
+++ b/shared.c
@@ -1,324 +1,313 @@
 /* shared.c: global vars + some callback functions
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 
 struct repolist cgit_repolist;
 struct repoinfo *cgit_repo;
 
 char *cgit_root_title   = "Git repository browser";
 char *cgit_css          = "/cgit.css";
 char *cgit_logo         = "/git-logo.png";
 char *cgit_logo_link    = "http://www.kernel.org/pub/software/scm/git/docs/";
 char *cgit_module_link  = "./?repo=%s&page=commit&id=%s";
 char *cgit_virtual_root = NULL;
 char *cgit_script_name  = CGIT_SCRIPT_NAME;
 char *cgit_cache_root   = "/var/cache/cgit";
 
 int cgit_nocache               =  0;
 int cgit_snapshots             =  0;
 int cgit_max_lock_attempts     =  5;
 int cgit_cache_root_ttl        =  5;
 int cgit_cache_repo_ttl        =  5;
 int cgit_cache_dynamic_ttl     =  5;
 int cgit_cache_static_ttl      = -1;
 int cgit_cache_max_create_time =  5;
 
 int cgit_max_msg_len = 60;
 int cgit_max_commit_count = 50;
 
-char *cgit_repo_name    = NULL;
-char *cgit_repo_desc    = NULL;
-char *cgit_repo_owner   = NULL;
-
 int cgit_query_has_symref = 0;
 int cgit_query_has_sha1   = 0;
 
 char *cgit_querystring  = NULL;
 char *cgit_query_repo   = NULL;
 char *cgit_query_page   = NULL;
 char *cgit_query_head   = NULL;
 char *cgit_query_search = NULL;
 char *cgit_query_sha1   = NULL;
 char *cgit_query_sha2   = NULL;
 char *cgit_query_path   = NULL;
 char *cgit_query_name   = NULL;
 int   cgit_query_ofs    = 0;
 
 int htmlfd = 0;
 
 int chk_zero(int result, char *msg)
 {
         if (result != 0)
                 die("%s: %s", msg, strerror(errno));
         return result;
 }
 
 int chk_positive(int result, char *msg)
 {
         if (result <= 0)
                 die("%s: %s", msg, strerror(errno));
         return result;
 }
 
 struct repoinfo *add_repo(const char *url)
 {
         struct repoinfo *ret;
 
         if (++cgit_repolist.count > cgit_repolist.length) {
                 if (cgit_repolist.length == 0)
                         cgit_repolist.length = 8;
                 else
                         cgit_repolist.length *= 2;
                 cgit_repolist.repos = xrealloc(cgit_repolist.repos,
                                                cgit_repolist.length *
                                                sizeof(struct repoinfo));
         }
 
         ret = &cgit_repolist.repos[cgit_repolist.count-1];
         ret->url = xstrdup(url);
         ret->name = ret->url;
         ret->path = NULL;
         ret->desc = NULL;
         ret->owner = NULL;
+        ret->defbranch = "master";
         ret->snapshots = cgit_snapshots;
         ret->module_link = cgit_module_link;
         return ret;
 }
 
 void cgit_global_config_cb(const char *name, const char *value)
 {
         if (!strcmp(name, "root-title"))
                 cgit_root_title = xstrdup(value);
         else if (!strcmp(name, "css"))
                 cgit_css = xstrdup(value);
         else if (!strcmp(name, "logo"))
                 cgit_logo = xstrdup(value);
         else if (!strcmp(name, "logo-link"))
                 cgit_logo_link = xstrdup(value);
         else if (!strcmp(name, "module-link"))
                 cgit_module_link = xstrdup(value);
         else if (!strcmp(name, "virtual-root"))
                 cgit_virtual_root = xstrdup(value);
         else if (!strcmp(name, "nocache"))
                 cgit_nocache = atoi(value);
         else if (!strcmp(name, "snapshots"))
                 cgit_snapshots = atoi(value);
         else if (!strcmp(name, "cache-root"))
                 cgit_cache_root = xstrdup(value);
         else if (!strcmp(name, "cache-root-ttl"))
                 cgit_cache_root_ttl = atoi(value);
         else if (!strcmp(name, "cache-repo-ttl"))
                 cgit_cache_repo_ttl = atoi(value);
         else if (!strcmp(name, "cache-static-ttl"))
                 cgit_cache_static_ttl = atoi(value);
         else if (!strcmp(name, "cache-dynamic-ttl"))
                 cgit_cache_dynamic_ttl = atoi(value);
         else if (!strcmp(name, "max-message-length"))
                 cgit_max_msg_len = atoi(value);
         else if (!strcmp(name, "max-commit-count"))
                 cgit_max_commit_count = atoi(value);
         else if (!strcmp(name, "repo.url"))
                 cgit_repo = add_repo(value);
         else if (!strcmp(name, "repo.name"))
                 cgit_repo->name = xstrdup(value);
         else if (cgit_repo && !strcmp(name, "repo.path"))
                 cgit_repo->path = xstrdup(value);
         else if (cgit_repo && !strcmp(name, "repo.desc"))
                 cgit_repo->desc = xstrdup(value);
         else if (cgit_repo && !strcmp(name, "repo.owner"))
                 cgit_repo->owner = xstrdup(value);
+        else if (cgit_repo && !strcmp(name, "repo.defbranch"))
+                cgit_repo->defbranch = xstrdup(value);
         else if (cgit_repo && !strcmp(name, "repo.snapshots"))
                 cgit_repo->snapshots = atoi(value);
         else if (cgit_repo && !strcmp(name, "repo.module-link"))
                 cgit_repo->module_link= xstrdup(value);
         else if (!strcmp(name, "include"))
                 cgit_read_config(value, cgit_global_config_cb);
 }
 
-void cgit_repo_config_cb(const char *name, const char *value)
-{
-        if (!strcmp(name, "name"))
-                cgit_repo_name = xstrdup(value);
-        else if (!strcmp(name, "desc"))
-                cgit_repo_desc = xstrdup(value);
-        else if (!strcmp(name, "owner"))
-                cgit_repo_owner = xstrdup(value);
-}
-
 void cgit_querystring_cb(const char *name, const char *value)
 {
         if (!strcmp(name,"r")) {
                 cgit_query_repo = xstrdup(value);
         } else if (!strcmp(name, "p")) {
                 cgit_query_page = xstrdup(value);
         } else if (!strcmp(name, "q")) {
                 cgit_query_search = xstrdup(value);
         } else if (!strcmp(name, "h")) {
                 cgit_query_head = xstrdup(value);
                 cgit_query_has_symref = 1;
         } else if (!strcmp(name, "id")) {
                 cgit_query_sha1 = xstrdup(value);
                 cgit_query_has_sha1 = 1;
         } else if (!strcmp(name, "id2")) {
                 cgit_query_sha2 = xstrdup(value);
                 cgit_query_has_sha1 = 1;
         } else if (!strcmp(name, "ofs")) {
                 cgit_query_ofs = atoi(value);
         } else if (!strcmp(name, "path")) {
                 cgit_query_path = xstrdup(value);
         } else if (!strcmp(name, "name")) {
                 cgit_query_name = xstrdup(value);
         }
 }
 
 void *cgit_free_commitinfo(struct commitinfo *info)
 {
         free(info->author);
         free(info->author_email);
         free(info->committer);
         free(info->committer_email);
         free(info->subject);
         free(info);
         return NULL;
 }
 
 int hextoint(char c)
 {
         if (c >= 'a' && c <= 'f')
                 return 10 + c - 'a';
         else if (c >= 'A' && c <= 'F')
                 return 10 + c - 'A';
         else if (c >= '0' && c <= '9')
                 return c - '0';
         else
                 return -1;
 }
 
 void cgit_diff_tree_cb(struct diff_queue_struct *q,
                        struct diff_options *options, void *data)
 {
         int i;
 
         for (i = 0; i < q->nr; i++) {
                 if (q->queue[i]->status == 'U')
                         continue;
                 ((filepair_fn)data)(q->queue[i]);
         }
 }
 
 static int load_mmfile(mmfile_t *file, const unsigned char *sha1)
 {
         enum object_type type;
 
         if (is_null_sha1(sha1)) {
                 file->ptr = (char *)"";
                 file->size = 0;
         } else {
                 file->ptr = read_sha1_file(sha1, &type, &file->size);
         }
         return 1;
 }
 
 /*
  * Receive diff-buffers from xdiff and concatenate them as
  * needed across multiple callbacks.
  *
  * This is basically a copy of xdiff-interface.c/xdiff_outf(),
  * ripped from git and modified to use globals instead of
  * a special callback-struct.
  */
 char *diffbuf = NULL;
 int buflen = 0;
 
 int filediff_cb(void *priv, mmbuffer_t *mb, int nbuf)
 {
         int i;
 
         for (i = 0; i < nbuf; i++) {
                 if (mb[i].ptr[mb[i].size-1] != '\n') {
                         /* Incomplete line */
                         diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
                         memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
                         buflen += mb[i].size;
                         continue;
                 }
 
                 /* we have a complete line */
                 if (!diffbuf) {
                         ((linediff_fn)priv)(mb[i].ptr, mb[i].size);
                         continue;
                 }
                 diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
                 memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
                 ((linediff_fn)priv)(diffbuf, buflen + mb[i].size);
                 free(diffbuf);
                 diffbuf = NULL;
                 buflen = 0;
         }
         if (diffbuf) {
                 ((linediff_fn)priv)(diffbuf, buflen);
                 free(diffbuf);
                 diffbuf = NULL;
                 buflen = 0;
         }
         return 0;
 }
 
 int cgit_diff_files(const unsigned char *old_sha1,
                      const unsigned char *new_sha1,
                      linediff_fn fn)
 {
         mmfile_t file1, file2;
         xpparam_t diff_params;
         xdemitconf_t emit_params;
         xdemitcb_t emit_cb;
 
         if (!load_mmfile(&file1, old_sha1) || !load_mmfile(&file2, new_sha1))
                 return 1;
 
         diff_params.flags = XDF_NEED_MINIMAL;
         emit_params.ctxlen = 3;
         emit_params.flags = XDL_EMIT_FUNCNAMES;
         emit_cb.outf = filediff_cb;
         emit_cb.priv = fn;
         xdl_diff(&file1, &file2, &diff_params, &emit_params, &emit_cb);
         return 0;
 }
 
 void cgit_diff_tree(const unsigned char *old_sha1,
                     const unsigned char *new_sha1,
                     filepair_fn fn)
 {
         struct diff_options opt;
         int ret;
 
         diff_setup(&opt);
         opt.output_format = DIFF_FORMAT_CALLBACK;
         opt.detect_rename = 1;
         opt.recursive = 1;
         opt.format_callback = cgit_diff_tree_cb;
         opt.format_callback_data = fn;
         diff_setup_done(&opt);
 
         if (old_sha1)
                 ret = diff_tree_sha1(old_sha1, new_sha1, "", &opt);
         else
                 ret = diff_root_tree_sha1(new_sha1, "", &opt);
         diffcore_std(&opt);
         diff_flush(&opt);
 }
 
 void cgit_diff_commit(struct commit *commit, filepair_fn fn)
 {
         unsigned char *old_sha1 = NULL;
 
         if (commit->parents)
                 old_sha1 = commit->parents->item->object.sha1;
         cgit_diff_tree(old_sha1, commit->object.sha1, fn);
 }