Handle missing default branch and error out on invalid branch names

When no branch is specified and the repository does not have a default branch,
use the first branch.

Also, print sensible errormessages when the repository does not contain any
branches and when invalid branchnames are specified.

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

1 files changed, 58 insertions, 4 deletions

diff --git a/cgit.c b/cgit.c
index 9ca93a7..e8acc03 100644
--- a/cgit.c
+++ b/cgit.c
@@ -1,264 +1,318 @@
 /* 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"
 
 static int cgit_prepare_cache(struct cacheitem *item)
 {
         if (!cgit_repo && cgit_query_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_repo) {
                 item->name = xstrdup(fmt("%s/index.html", cgit_cache_root));
                 item->ttl = cgit_cache_root_ttl;
                 return 1;
         }
 
         if (!cgit_cmd) {
                 item->name = xstrdup(fmt("%s/%s/index.%s.html", cgit_cache_root,
                                          cache_safe_filename(cgit_repo->url),
                                          cache_safe_filename(cgit_querystring)));
                 item->ttl = cgit_cache_repo_ttl;
         } else {
                 item->name = xstrdup(fmt("%s/%s/%s/%s.html", cgit_cache_root,
                                          cache_safe_filename(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;
 }
 
+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 repoinfo *repo)
+{
+        struct refmatch info;
+
+        info.req_ref = repo->defbranch;
+        info.first_ref = NULL;
+        info.match = 0;
+        for_each_branch_ref(find_current_ref, &info);
+        if (info.match)
+                return info.req_ref;
+        else
+                return info.first_ref;
+}
+
 static void cgit_print_repo_page(struct cacheitem *item)
 {
-        char *title;
+        char *title, *tmp;
         int show_search;
-
-        if (!cgit_query_head)
-                cgit_query_head = cgit_repo->defbranch;
+        unsigned char sha1[20];
 
         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_head) {
+                cgit_query_head = xstrdup(find_default_branch(cgit_repo));
+                cgit_repo->defbranch = cgit_query_head;
+        }
+
+        if (!cgit_query_head) {
+                cgit_print_docstart(title, item);
+                cgit_print_pageheader(title, 0);
+                cgit_print_error("Repository seems to be empty");
+                cgit_print_docend();
+                return;
+        }
+
+        if (get_sha1(cgit_query_head, sha1)) {
+                tmp = xstrdup(cgit_query_head);
+                cgit_query_head = cgit_repo->defbranch;
+                cgit_print_docstart(title, item);
+                cgit_print_pageheader(title, 0);
+                cgit_print_error(fmt("Invalid branch: %s", tmp));
+                cgit_print_docend();
+                return;
+        }
+
         if ((cgit_cmd == CMD_SNAPSHOT) && cgit_repo->snapshots) {
                 cgit_print_snapshot(item, cgit_query_head, cgit_query_sha1,
                                     cgit_repobasename(cgit_repo->url),
                                     cgit_query_path,
                                     cgit_repo->snapshots );
                 return;
         }
 
         if (cgit_cmd == CMD_PATCH) {
                 cgit_print_patch(cgit_query_sha1, item);
                 return;
         }
 
         if (cgit_cmd == CMD_BLOB) {
                 cgit_print_blob(item, cgit_query_sha1, cgit_query_path);
                 return;
         }
 
         show_search = (cgit_cmd == CMD_LOG);
         cgit_print_docstart(title, item);
         if (!cgit_cmd) {
                 cgit_print_pageheader("summary", show_search);
                 cgit_print_summary();
                 cgit_print_docend();
                 return;
         }
 
         cgit_print_pageheader(cgit_query_page, show_search);
 
         switch(cgit_cmd) {
         case CMD_LOG:
                 cgit_print_log(cgit_query_sha1, cgit_query_ofs,
                                cgit_max_commit_count, cgit_query_grep, cgit_query_search,
                                cgit_query_path, 1);
                 break;
         case CMD_TREE:
                 cgit_print_tree(cgit_query_sha1, cgit_query_path);
                 break;
         case CMD_COMMIT:
                 cgit_print_commit(cgit_query_sha1);
                 break;
         case CMD_REFS:
                 cgit_print_refs();
                 break;
         case CMD_TAG:
                 cgit_print_tag(cgit_query_sha1);
                 break;
         case CMD_DIFF:
                 cgit_print_diff(cgit_query_sha1, cgit_query_sha2, cgit_query_path);
                 break;
         default:
                 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_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;
         const char *cgit_config_env = getenv("CGIT_CONFIG");
 
         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_env ? cgit_config_env : CGIT_CONFIG,
                          cgit_global_config_cb);
         cgit_repo = NULL;
         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;
 }