guess default branch from HEAD

This is a saner alternative than hardcoding the default branch to be
"master". The add_repo() function will now check for a symbolic ref in
repo_path/HEAD. If there is a suitable one, overwrite repo->defbranch
with it. Note that you'll need to strip the newline from the file (->
len-17).

If HEAD is a symbolic link pointing directly to a branch below
refs/heads/, do a readlink() instead to find the ref name.

Signed-off-by: Julius Plenz <plenz@cis.fu-berlin.de>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 4721c1e01335e10bd0fff7060b8281796a7ea557..c2c56800e097fd599a69788c872f72c205b36619 100644 (file)
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -377,7 +377,8 @@ repo.commit-filter::
 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".
+       as default instead. Default value: branch pointed to by HEAD, or
+       "master" if there is no suitable HEAD.
 
 repo.desc::
        The value to show as repository description. Default value: none.

diff --git a/scan-tree.c b/scan-tree.c
index 378d795e854a3965c38673939fd3785f6e3fe92e..a429a9f4afeb327802a7a485c7126a3247670d0f 100644 (file)
--- a/scan-tree.c
+++ b/scan-tree.c
@@ -68,6 +68,39 @@ static char *xstrrchr(char *s, char *from, int c)
        return from < s ? NULL : from;
 }
 
+static char *guess_defbranch(const char *repo_path)
+{
+       int fd, len;
+       char buffer[256];
+       char *ref_start;
+       char *head;
+
+       head = fmt("%s/HEAD", repo_path);
+       fd = open(head, O_RDONLY);
+       if (fd == -1)
+               return xstrdup("master");
+
+       memset(buffer, 0, sizeof(buffer));
+       len = read_in_full(fd, buffer, sizeof(buffer)-1);
+       close(fd);
+
+       if(!memcmp(buffer, "ref: refs/heads/", 16))
+               return xstrndup(buffer+16, len-17);
+
+       if(strlen(buffer) == 41) {
+               /* probably contains a SHA1 sum */
+               memset(buffer, 0, sizeof(buffer));
+               if(readlink(head, buffer, sizeof(buffer)-1)) {
+                       ref_start = memmem(buffer, sizeof(buffer)-1, "refs/heads/", 11);
+                       if(ref_start)
+                               return xstrdup(ref_start+11);
+               }
+       }
+
+       return xstrdup("master");
+}
+
+
 static void add_repo(const char *base, const char *path, repo_config_fn fn)
 {
        struct stat st;
@@ -105,6 +138,9 @@ static void add_repo(const char *base, const char *path, repo_config_fn fn)
                        *p = '\0';
        repo->name = repo->url;
        repo->path = xstrdup(path);
+
+       repo->defbranch = guess_defbranch(repo->path);
+
        while (!owner) {
                if ((pwd = getpwuid(st.st_uid)) == NULL) {
                        fprintf(stderr, "Error reading owner-info for %s: %s (%d)\n",