[PATCHv8 4/6] worktree: check if a submodule uses worktrees

From

Stefan Beller <sbeller@google.com>

Date

Dec 12, 2016, 19:04 UTC

Message-ID

<20161212190435.10358-5-sbeller@google.com>

In-Reply-To

<20161212190435.10358-1-sbeller@google.com>

An earlier approach:
  "Implement submodule_get_worktrees and just count them", however:
  This can be done cheaply (both in new code to write as well as run time)
  by obtaining the list of worktrees based off that submodules git
  directory. However as we have loaded the variables for the current
  repository, the values in the submodule worktree
  can be wrong, e.g.
  * core.ignorecase may differ between these two repositories
  * the ref resolution is broken (refs/heads/branch in the submodule
    resolves to the sha1 value of the `branch` in the current repository
    that may not exist or have another sha1)

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 worktree.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 worktree.h |  5 +++++
 2 files changed, 55 insertions(+)

diff --git a/worktree.c b/worktree.c
index eb6121263b..d4606aa8cd 100644
--- a/worktree.c
+++ b/worktree.c
@@ -380,3 +380,53 @@ const struct worktree *find_shared_symref(const char *symref,
 
 	return existing;
 }
+
+int submodule_uses_worktrees(const char *path)
+{
+	char *submodule_gitdir;
+	struct strbuf sb = STRBUF_INIT;
+	DIR *dir;
+	struct dirent *d;
+	int ret;
+	struct repository_format format;
+
+	submodule_gitdir = git_pathdup_submodule(path, "%s", "");
+	if (!submodule_gitdir)
+		return 0;
+
+	/* The env would be set for the superproject. */
+	get_common_dir_noenv(&sb, submodule_gitdir);
+
+	/*
+	 * The check below is only known to be good for repository format
+	 * version 0 at the time of writing this code.
+	 */
+	strbuf_addstr(&sb, "/config");
+	read_repository_format(&format, sb.buf);
+	if (format.version != 0) {
+		strbuf_release(&sb);
+		return 1;
+	}
+
+	/* Replace config by worktrees. */
+	strbuf_setlen(&sb, sb.len - strlen("config"));
+	strbuf_addstr(&sb, "worktrees");
+
+	/* See if there is any file inside the worktrees directory. */
+	dir = opendir(sb.buf);
+	strbuf_release(&sb);
+	free(submodule_gitdir);
+
+	if (!dir)
+		return 0;
+
+	while ((d = readdir(dir)) != NULL) {
+		if (is_dot_or_dotdot(d->d_name))
+			continue;
+
+		ret = 1;
+		break;
+	}
+	closedir(dir);
+	return ret;
+}
diff --git a/worktree.h b/worktree.h
index d59ce1fee8..6bfb985203 100644
--- a/worktree.h
+++ b/worktree.h
@@ -27,6 +27,11 @@ struct worktree {
  */
 extern struct worktree **get_worktrees(unsigned flags);
 
+/*
+ * Returns 1 if linked worktrees exist, 0 otherwise.
+ */
+extern int submodule_uses_worktrees(const char *path);
+
 /*
  * Return git dir of the worktree. Note that the path may be relative.
  * If wt is NULL, git dir of current worktree is returned.

-- 
2.11.0.rc2.49.ge1f3b0c.dirty