[PATCH 01/16] path: refactor `repo_common_path()` family of functions

[Patrick Steinhardt <ps@pks.im>]

The functions provided by the "path" subsystem to derive repository
paths for the commondir, gitdir, worktrees and submodules are quite
inconsistent. Some functions have a `strbuf_` prefix, others have
different return values, some don't provide a variant working on top of
`strbuf`s.

We're thus about to refactor all of these family of functions so that
they follow a common pattern:

  - `repo_*_path()` returns an allocated string.

  - `repo_*_path_append()` appends the path to the caller-provided
    buffer while returning a constant pointer to the buffer. This
    clarifies whether the buffer is being appended to or rewritten,
    which otherwise wasn't immediately obvious.

  - `repo_*_path_replace()` replaces contents of the buffer with the
    computed path, again returning a pointer to the buffer contents.

Refactor the commondir family of functions accordingly and adapt all
callers.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 loose.c    |  6 +++---
 path.c     | 32 ++++++++++++++++++++++++++++----
 path.h     | 30 +++++++++++++++++-------------
 refs.c     |  4 ++--
 setup.c    |  4 ++--
 worktree.c |  5 ++---
 6 files changed, 54 insertions(+), 27 deletions(-)

diff --git a/loose.c b/loose.c
index 897ba389da..51ef490f93 100644
--- a/loose.c
+++ b/loose.c
@@ -75,7 +75,7 @@ static int load_one_loose_object_map(struct repository *repo, struct object_dire
 	insert_loose_map(dir, repo->hash_algo->empty_blob, repo->compat_hash_algo->empty_blob);
 	insert_loose_map(dir, repo->hash_algo->null_oid, repo->compat_hash_algo->null_oid);
 
-	strbuf_git_common_path(&path, repo, "objects/loose-object-idx");
+	repo_common_path_replace(repo, &path, "objects/loose-object-idx");
 	fp = fopen(path.buf, "rb");
 	if (!fp) {
 		strbuf_release(&path);
@@ -133,7 +133,7 @@ int repo_write_loose_object_map(struct repository *repo)
 	if (!should_use_loose_object_map(repo))
 		return 0;
 
-	strbuf_git_common_path(&path, repo, "objects/loose-object-idx");
+	repo_common_path_replace(repo, &path, "objects/loose-object-idx");
 	fd = hold_lock_file_for_update_timeout(&lock, path.buf, LOCK_DIE_ON_ERROR, -1);
 	iter = kh_begin(map);
 	if (write_in_full(fd, loose_object_header, strlen(loose_object_header)) < 0)
@@ -174,7 +174,7 @@ static int write_one_object(struct repository *repo, const struct object_id *oid
 	struct stat st;
 	struct strbuf buf = STRBUF_INIT, path = STRBUF_INIT;
 
-	strbuf_git_common_path(&path, repo, "objects/loose-object-idx");
+	repo_common_path_replace(repo, &path, "objects/loose-object-idx");
 	hold_lock_file_for_update_timeout(&lock, path.buf, LOCK_DIE_ON_ERROR, -1);
 
 	fd = open(path.buf, O_WRONLY | O_CREAT | O_APPEND, 0666);
diff --git a/path.c b/path.c
index 07964f5d32..273b649e00 100644
--- a/path.c
+++ b/path.c
@@ -414,7 +414,7 @@ static void strbuf_worktree_gitdir(struct strbuf *buf,
 	else if (!wt->id)
 		strbuf_addstr(buf, repo->commondir);
 	else
-		strbuf_git_common_path(buf, repo, "worktrees/%s", wt->id);
+		repo_common_path_append(repo, buf, "worktrees/%s", wt->id);
 }
 
 void repo_git_pathv(const struct repository *repo,
@@ -596,14 +596,38 @@ void repo_common_pathv(const struct repository *repo,
 	strbuf_cleanup_path(sb);
 }
 
-void strbuf_git_common_path(struct strbuf *sb,
-			    const struct repository *repo,
-			    const char *fmt, ...)
+char *repo_common_path(const struct repository *repo,
+		       const char *fmt, ...)
+{
+	struct strbuf sb = STRBUF_INIT;
+	va_list args;
+	va_start(args, fmt);
+	repo_common_pathv(repo, &sb, fmt, args);
+	va_end(args);
+	return strbuf_detach(&sb, NULL);
+}
+
+const char *repo_common_path_append(const struct repository *repo,
+				    struct strbuf *sb,
+				    const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	repo_common_pathv(repo, sb, fmt, args);
+	va_end(args);
+	return sb->buf;
+}
+
+const char *repo_common_path_replace(const struct repository *repo,
+				     struct strbuf *sb,
+				     const char *fmt, ...)
 {
 	va_list args;
+	strbuf_reset(sb);
 	va_start(args, fmt);
 	repo_common_pathv(repo, sb, fmt, args);
 	va_end(args);
+	return sb->buf;
 }
 
 static struct passwd *getpw_str(const char *username, size_t len)
diff --git a/path.h b/path.h
index 5f6c85e5f8..3c75495e1a 100644
--- a/path.h
+++ b/path.h
@@ -25,22 +25,20 @@ char *mkpathdup(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
 
 /*
- * The `strbuf_git_common_path` family of functions will construct a path into a
+ * The `repo_common_path` family of functions will construct a path into a
  * repository's common git directory, which is shared by all worktrees.
  */
-
-/*
- * Constructs a path into the common git directory of repository `repo` and
- * append it in the provided buffer `sb`.
- */
-void strbuf_git_common_path(struct strbuf *sb,
-			    const struct repository *repo,
-			    const char *fmt, ...)
+char *repo_common_path(const struct repository *repo,
+		       const char *fmt, ...)
+	__attribute__((format (printf, 2, 3)));
+const char *repo_common_path_append(const struct repository *repo,
+				    struct strbuf *sb,
+				    const char *fmt, ...)
+	__attribute__((format (printf, 3, 4)));
+const char *repo_common_path_replace(const struct repository *repo,
+				     struct strbuf *sb,
+				     const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
-void repo_common_pathv(const struct repository *repo,
-		       struct strbuf *buf,
-		       const char *fmt,
-		       va_list args);
 
 /*
  * The `repo_git_path` family of functions will construct a path into a repository's
@@ -243,6 +241,12 @@ struct strbuf *get_pathname(void);
 #  include "strbuf.h"
 #  include "repository.h"
 
+/* Internal implementation detail that should not be used. */
+void repo_common_pathv(const struct repository *repo,
+		       struct strbuf *buf,
+		       const char *fmt,
+		       va_list args);
+
 /*
  * Return a statically allocated path into the main repository's
  * (the_repository) common git directory.
diff --git a/refs.c b/refs.c
index f4094a326a..daf6a84205 100644
--- a/refs.c
+++ b/refs.c
@@ -2184,8 +2184,8 @@ struct ref_store *get_worktree_ref_store(const struct worktree *wt)
 
 	if (wt->id) {
 		struct strbuf common_path = STRBUF_INIT;
-		strbuf_git_common_path(&common_path, wt->repo,
-				      "worktrees/%s", wt->id);
+		repo_common_path_append(wt->repo, &common_path,
+					"worktrees/%s", wt->id);
 		refs = ref_store_init(wt->repo, wt->repo->ref_storage_format,
 				      common_path.buf, REF_STORE_ALL_CAPS);
 		strbuf_release(&common_path);
diff --git a/setup.c b/setup.c
index 8a488f3e7c..74b5ba5325 100644
--- a/setup.c
+++ b/setup.c
@@ -792,7 +792,7 @@ int upgrade_repository_format(int target_version)
 	struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
 	int ret;
 
-	strbuf_git_common_path(&sb, the_repository, "config");
+	repo_common_path_append(the_repository, &sb, "config");
 	read_repository_format(&repo_fmt, sb.buf);
 	strbuf_release(&sb);
 
@@ -2242,7 +2242,7 @@ void initialize_repository_version(int hash_algo,
 		struct strbuf config = STRBUF_INIT;
 		struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
 
-		strbuf_git_common_path(&config, the_repository, "config");
+		repo_common_path_append(the_repository, &config, "config");
 		read_repository_format(&repo_fmt, config.buf);
 
 		if (repo_fmt.v1_only_extensions.nr)
diff --git a/worktree.c b/worktree.c
index 248bbb39d4..f8d6e7127f 100644
--- a/worktree.c
+++ b/worktree.c
@@ -104,7 +104,7 @@ struct worktree *get_linked_worktree(const char *id,
 	if (!id)
 		die("Missing linked worktree name");
 
-	strbuf_git_common_path(&path, the_repository, "worktrees/%s/gitdir", id);
+	repo_common_path_append(the_repository, &path, "worktrees/%s/gitdir", id);
 	if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
 		/* invalid gitdir file */
 		goto done;
@@ -731,8 +731,7 @@ static ssize_t infer_backlink(const char *gitfile, struct strbuf *inferred)
 	id++; /* advance past '/' to point at <id> */
 	if (!*id)
 		goto error;
-	strbuf_reset(inferred);
-	strbuf_git_common_path(inferred, the_repository, "worktrees/%s", id);
+	repo_common_path_replace(the_repository, inferred, "worktrees/%s", id);
 	if (!is_directory(inferred->buf))
 		goto error;
 

-- 
2.48.1.538.gc4cfc42d60.dirty