From mboxrd@z Thu Jan  1 00:00:00 1970
From: hjemli at gmail.com (Lars Hjemli)
Date: Thu, 10 Mar 2011 18:22:59 +0100
Subject: [PATCH 1/5] guess default branch from HEAD
In-Reply-To: <1299773004-27380-1-git-send-email-plenz@cis.fu-berlin.de>
References: <1299773004-27380-1-git-send-email-plenz@cis.fu-berlin.de>
Message-ID: <AANLkTikfEQG2ibazmo_KxTzd2ZUUnGa0MXqFdJpnfE6W@mail.gmail.com>

On Thu, Mar 10, 2011 at 17:03, Julius Plenz <plenz at cis.fu-berlin.de> wrote:
> 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.

I agree with the motivation, but...

> --- a/scan-tree.c
> +++ b/scan-tree.c
> @@ -75,6 +75,8 @@ static void add_repo(const char *base, const char *path, repo_config_fn fn)
> ? ? ? ?char *rel, *p, *slash;
> ? ? ? ?int n;
> ? ? ? ?size_t size;
> + ? ? ? char buffer[256];
> + ? ? ? int fd;
>
> ? ? ? ?if (stat(path, &st)) {
> ? ? ? ? ? ? ? ?fprintf(stderr, "Error accessing %s: %s (%d)\n",
> @@ -105,6 +107,17 @@ static void add_repo(const char *base, const char *path, repo_config_fn fn)
> ? ? ? ? ? ? ? ? ? ? ? ?*p = '\0';
> ? ? ? ?repo->name = repo->url;
> ? ? ? ?repo->path = xstrdup(path);
> +
> + ? ? ? fd = open(fmt("%s/HEAD", repo->path), O_RDONLY);
> + ? ? ? if (fd != -1) {
> + ? ? ? ? ? ? ? int len;
> + ? ? ? ? ? ? ? memset(buffer, 0, sizeof(buffer)-1);
> + ? ? ? ? ? ? ? len = read_in_full(fd, buffer, sizeof(buffer)-1);
> + ? ? ? ? ? ? ? if(!memcmp(buffer, "ref: refs/heads/", 16))
> + ? ? ? ? ? ? ? ? ? ? ? repo->defbranch = xstrndup(buffer+16, len-17);
> + ? ? ? ? ? ? ? close(fd);
> + ? ? ? }
> +

...since git supports fs links, you'll need to lstat() and then either
readlink() or read_in_full(). And if you readlink(), you'll obviously
need to parse the result differently.

--
larsh