Merge branch 'jk/git-path'

git_path() and mkpath() are handy helper functions but it is easy
to misuse, as the callers need to be careful to keep the number of
active results below 4.  Their uses have been reduced.

* jk/git-path:
  memoize common git-path "constant" files
  get_repo_path: refactor path-allocation
  find_hook: keep our own static buffer
  refs.c: remove_empty_directories can take a strbuf
  refs.c: avoid git_path assignment in lock_ref_sha1_basic
  refs.c: avoid repeated git_path calls in rename_tmp_log
  refs.c: simplify strbufs in reflog setup and writing
  path.c: drop git_path_submodule
  refs.c: remove extra git_path calls from read_loose_refs
  remote.c: drop extraneous local variable from migrate_file
  prefer mkpathdup to mkpath in assignments
  prefer git_pathdup to git_path in some possibly-dangerous cases
  add_to_alternates_file: don't add duplicate entries
  t5700: modernize style
  cache.h: complete set of git_path_submodule helpers
  cache.h: clarify documentation for git_path, et al

9 files changed, 84 insertions, 69 deletions

diff --git a/builtin/blame.c b/builtin/blame.c
index 04e4864f8b..4db01c195c 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -2227,20 +2227,19 @@ static struct commit_list **append_parent(struct commit_list **tail, const unsig
 static void append_merge_parents(struct commit_list **tail)
 {
 	int merge_head;
-	const char *merge_head_file = git_path("MERGE_HEAD");
 	struct strbuf line = STRBUF_INIT;
 
-	merge_head = open(merge_head_file, O_RDONLY);
+	merge_head = open(git_path_merge_head(), O_RDONLY);
 	if (merge_head < 0) {
 		if (errno == ENOENT)
 			return;
-		die("cannot open '%s' for reading", merge_head_file);
+		die("cannot open '%s' for reading", git_path_merge_head());
 	}
 
 	while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
 		unsigned char sha1[20];
 		if (line.len < 40 || get_sha1_hex(line.buf, sha1))
-			die("unknown line in '%s': %s", merge_head_file, line.buf);
+			die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
 		tail = append_parent(tail, sha1);
 	}
 	close(merge_head);
diff --git a/builtin/clone.c b/builtin/clone.c
index 5169746b64..578da85254 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -99,51 +99,66 @@ static const char *argv_submodule[] = {
 	"submodule", "update", "--init", "--recursive", NULL
 };
 
-static char *get_repo_path(const char *repo, int *is_bundle)
+static const char *get_repo_path_1(struct strbuf *path, int *is_bundle)
 {
 	static char *suffix[] = { "/.git", "", ".git/.git", ".git" };
 	static char *bundle_suffix[] = { ".bundle", "" };
+	size_t baselen = path->len;
 	struct stat st;
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(suffix); i++) {
-		const char *path;
-		path = mkpath("%s%s", repo, suffix[i]);
-		if (stat(path, &st))
+		strbuf_setlen(path, baselen);
+		strbuf_addstr(path, suffix[i]);
+		if (stat(path->buf, &st))
 			continue;
-		if (S_ISDIR(st.st_mode) && is_git_directory(path)) {
+		if (S_ISDIR(st.st_mode) && is_git_directory(path->buf)) {
 			*is_bundle = 0;
-			return xstrdup(absolute_path(path));
+			return path->buf;
 		} else if (S_ISREG(st.st_mode) && st.st_size > 8) {
 			/* Is it a "gitfile"? */
 			char signature[8];
-			int len, fd = open(path, O_RDONLY);
+			const char *dst;
+			int len, fd = open(path->buf, O_RDONLY);
 			if (fd < 0)
 				continue;
 			len = read_in_full(fd, signature, 8);
 			close(fd);
 			if (len != 8 || strncmp(signature, "gitdir: ", 8))
 				continue;
-			path = read_gitfile(path);
-			if (path) {
+			dst = read_gitfile(path->buf);
+			if (dst) {
 				*is_bundle = 0;
-				return xstrdup(absolute_path(path));
+				return dst;
 			}
 		}
 	}
 
 	for (i = 0; i < ARRAY_SIZE(bundle_suffix); i++) {
-		const char *path;
-		path = mkpath("%s%s", repo, bundle_suffix[i]);
-		if (!stat(path, &st) && S_ISREG(st.st_mode)) {
+		strbuf_setlen(path, baselen);
+		strbuf_addstr(path, bundle_suffix[i]);
+		if (!stat(path->buf, &st) && S_ISREG(st.st_mode)) {
 			*is_bundle = 1;
-			return xstrdup(absolute_path(path));
+			return path->buf;
 		}
 	}
 
 	return NULL;
 }
 
+static char *get_repo_path(const char *repo, int *is_bundle)
+{
+	struct strbuf path = STRBUF_INIT;
+	const char *raw;
+	char *canon;
+
+	strbuf_addstr(&path, repo);
+	raw = get_repo_path_1(&path, is_bundle);
+	canon = raw ? xstrdup(absolute_path(raw)) : NULL;
+	strbuf_release(&path);
+	return canon;
+}
+
 static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
 {
 	const char *end = repo + strlen(repo), *start, *ptr;
diff --git a/builtin/commit.c b/builtin/commit.c
index 7314f33885..4cbd5ff4de 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -166,9 +166,9 @@ static int opt_parse_m(const struct option *opt, const char *arg, int unset)
 
 static void determine_whence(struct wt_status *s)
 {
-	if (file_exists(git_path("MERGE_HEAD")))
+	if (file_exists(git_path_merge_head()))
 		whence = FROM_MERGE;
-	else if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
+	else if (file_exists(git_path_cherry_pick_head())) {
 		whence = FROM_CHERRY_PICK;
 		if (file_exists(git_path(SEQ_DIR)))
 			sequencer_in_use = 1;
@@ -725,12 +725,12 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		format_commit_message(commit, "fixup! %s\n\n",
 				      &sb, &ctx);
 		hook_arg1 = "message";
-	} else if (!stat(git_path("MERGE_MSG"), &statbuf)) {
-		if (strbuf_read_file(&sb, git_path("MERGE_MSG"), 0) < 0)
+	} else if (!stat(git_path_merge_msg(), &statbuf)) {
+		if (strbuf_read_file(&sb, git_path_merge_msg(), 0) < 0)
 			die_errno(_("could not read MERGE_MSG"));
 		hook_arg1 = "merge";
-	} else if (!stat(git_path("SQUASH_MSG"), &statbuf)) {
-		if (strbuf_read_file(&sb, git_path("SQUASH_MSG"), 0) < 0)
+	} else if (!stat(git_path_squash_msg(), &statbuf)) {
+		if (strbuf_read_file(&sb, git_path_squash_msg(), 0) < 0)
 			die_errno(_("could not read SQUASH_MSG"));
 		hook_arg1 = "squash";
 	} else if (template_file) {
@@ -1684,10 +1684,10 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		if (!reflog_msg)
 			reflog_msg = "commit (merge)";
 		pptr = &commit_list_insert(current_head, pptr)->next;
-		fp = fopen(git_path("MERGE_HEAD"), "r");
+		fp = fopen(git_path_merge_head(), "r");
 		if (fp == NULL)
 			die_errno(_("could not open '%s' for reading"),
-				  git_path("MERGE_HEAD"));
+				  git_path_merge_head());
 		while (strbuf_getline(&m, fp, '\n') != EOF) {
 			struct commit *parent;
 
@@ -1698,8 +1698,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		}
 		fclose(fp);
 		strbuf_release(&m);
-		if (!stat(git_path("MERGE_MODE"), &statbuf)) {
-			if (strbuf_read_file(&sb, git_path("MERGE_MODE"), 0) < 0)
+		if (!stat(git_path_merge_mode(), &statbuf)) {
+			if (strbuf_read_file(&sb, git_path_merge_mode(), 0) < 0)
 				die_errno(_("could not read MERGE_MODE"));
 			if (!strcmp(sb.buf, "no-ff"))
 				allow_fast_forward = 0;
@@ -1775,12 +1775,12 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	}
 	ref_transaction_free(transaction);
 
-	unlink(git_path("CHERRY_PICK_HEAD"));
-	unlink(git_path("REVERT_HEAD"));
-	unlink(git_path("MERGE_HEAD"));
-	unlink(git_path("MERGE_MSG"));
-	unlink(git_path("MERGE_MODE"));
-	unlink(git_path("SQUASH_MSG"));
+	unlink(git_path_cherry_pick_head());
+	unlink(git_path_revert_head());
+	unlink(git_path_merge_head());
+	unlink(git_path_merge_msg());
+	unlink(git_path_merge_mode());
+	unlink(git_path_squash_msg());
 
 	if (commit_index_files())
 		die (_("Repository has been updated, but unable to write\n"
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 6d743aa4eb..d3a08545ad 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -591,7 +591,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 	const char *what, *kind;
 	struct ref *rm;
 	char *url;
-	const char *filename = dry_run ? "/dev/null" : git_path("FETCH_HEAD");
+	const char *filename = dry_run ? "/dev/null" : git_path_fetch_head();
 	int want_status;
 
 	fp = fopen(filename, "a");
@@ -834,7 +834,7 @@ static void check_not_current_branch(struct ref *ref_map)
 
 static int truncate_fetch_head(void)
 {
-	const char *filename = git_path("FETCH_HEAD");
+	const char *filename = git_path_fetch_head();
 	FILE *fp = fopen(filename, "w");
 
 	if (!fp)
diff --git a/builtin/fsck.c b/builtin/fsck.c
index f4b87e9b33..079470342f 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -243,13 +243,14 @@ static void check_unreachable_object(struct object *obj)
 			printf("dangling %s %s\n", typename(obj->type),
 			       sha1_to_hex(obj->sha1));
 		if (write_lost_and_found) {
-			const char *filename = git_path("lost-found/%s/%s",
+			char *filename = git_pathdup("lost-found/%s/%s",
 				obj->type == OBJ_COMMIT ? "commit" : "other",
 				sha1_to_hex(obj->sha1));
 			FILE *f;
 
 			if (safe_create_leading_directories_const(filename)) {
 				error("Could not create lost-found");
+				free(filename);
 				return;
 			}
 			if (!(f = fopen(filename, "w")))
@@ -262,6 +263,7 @@ static void check_unreachable_object(struct object *obj)
 			if (fclose(f))
 				die_errno("Could not finish '%s'",
 					  filename);
+			free(filename);
 		}
 		return;
 	}
diff --git a/builtin/merge.c b/builtin/merge.c
index 85c54dcd5a..a0edacab20 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -231,9 +231,9 @@ static struct option builtin_merge_options[] = {
 /* Cleans up metadata that is uninteresting after a succeeded merge. */
 static void drop_save(void)
 {
-	unlink(git_path("MERGE_HEAD"));
-	unlink(git_path("MERGE_MSG"));
-	unlink(git_path("MERGE_MODE"));
+	unlink(git_path_merge_head());
+	unlink(git_path_merge_msg());
+	unlink(git_path_merge_mode());
 }
 
 static int save_state(unsigned char *stash)
@@ -338,7 +338,7 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
 	struct pretty_print_context ctx = {0};
 
 	printf(_("Squash commit -- not updating HEAD\n"));
-	filename = git_path("SQUASH_MSG");
+	filename = git_path_squash_msg();
 	fd = open(filename, O_WRONLY | O_CREAT, 0666);
 	if (fd < 0)
 		die_errno(_("Could not write to '%s'"), filename);
@@ -754,7 +754,7 @@ static void add_strategies(const char *string, unsigned attr)
 
 static void write_merge_msg(struct strbuf *msg)
 {
-	const char *filename = git_path("MERGE_MSG");
+	const char *filename = git_path_merge_msg();
 	int fd = open(filename, O_WRONLY | O_CREAT, 0666);
 	if (fd < 0)
 		die_errno(_("Could not open '%s' for writing"),
@@ -766,7 +766,7 @@ static void write_merge_msg(struct strbuf *msg)
 
 static void read_merge_msg(struct strbuf *msg)
 {
-	const char *filename = git_path("MERGE_MSG");
+	const char *filename = git_path_merge_msg();
 	strbuf_reset(msg);
 	if (strbuf_read_file(msg, filename, 0) < 0)
 		die_errno(_("Could not read from '%s'"), filename);
@@ -799,10 +799,10 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 		strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
 	write_merge_msg(&msg);
 	if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
-			    git_path("MERGE_MSG"), "merge", NULL))
+			    git_path_merge_msg(), "merge", NULL))
 		abort_commit(remoteheads, NULL);
 	if (0 < option_edit) {
-		if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
+		if (launch_editor(git_path_merge_msg(), NULL, NULL))
 			abort_commit(remoteheads, NULL);
 	}
 	read_merge_msg(&msg);
@@ -865,7 +865,7 @@ static int suggest_conflicts(void)
 	FILE *fp;
 	struct strbuf msgbuf = STRBUF_INIT;
 
-	filename = git_path("MERGE_MSG");
+	filename = git_path_merge_msg();
 	fp = fopen(filename, "a");
 	if (!fp)
 		die_errno(_("Could not open '%s' for writing"), filename);
@@ -967,7 +967,7 @@ static void write_merge_state(struct commit_list *remoteheads)
 		}
 		strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
 	}
-	filename = git_path("MERGE_HEAD");
+	filename = git_path_merge_head();
 	fd = open(filename, O_WRONLY | O_CREAT, 0666);
 	if (fd < 0)
 		die_errno(_("Could not open '%s' for writing"), filename);
@@ -977,7 +977,7 @@ static void write_merge_state(struct commit_list *remoteheads)
 	strbuf_addch(&merge_msg, '\n');
 	write_merge_msg(&merge_msg);
 
-	filename = git_path("MERGE_MODE");
+	filename = git_path_merge_mode();
 	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 	if (fd < 0)
 		die_errno(_("Could not open '%s' for writing"), filename);
@@ -1070,7 +1070,7 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
 	if (!merge_names)
 		merge_names = &fetch_head_file;
 
-	filename = git_path("FETCH_HEAD");
+	filename = git_path_fetch_head();
 	fd = open(filename, O_RDONLY);
 	if (fd < 0)
 		die_errno(_("could not open '%s' for reading"), filename);
@@ -1204,7 +1204,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		int nargc = 2;
 		const char *nargv[] = {"reset", "--merge", NULL};
 
-		if (!file_exists(git_path("MERGE_HEAD")))
+		if (!file_exists(git_path_merge_head()))
 			die(_("There is no merge to abort (MERGE_HEAD missing)."));
 
 		/* Invoke 'git reset --merge' */
@@ -1215,7 +1215,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	if (read_cache_unmerged())
 		die_resolve_conflict("merge");
 
-	if (file_exists(git_path("MERGE_HEAD"))) {
+	if (file_exists(git_path_merge_head())) {
 		/*
 		 * There is no unmerged entry, don't advise 'git
 		 * add/rm <file>', just 'git commit'.
@@ -1226,7 +1226,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		else
 			die(_("You have not concluded your merge (MERGE_HEAD exists)."));
 	}
-	if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
+	if (file_exists(git_path_cherry_pick_head())) {
 		if (advice_resolve_conflict)
 			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
 			    "Please, commit your changes before you merge."));
diff --git a/builtin/remote.c b/builtin/remote.c
index cc3c7410f3..181668dedd 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -581,7 +581,6 @@ static int migrate_file(struct remote *remote)
 {
 	struct strbuf buf = STRBUF_INIT;
 	int i;
-	const char *path = NULL;
 
 	strbuf_addf(&buf, "remote.%s.url", remote->name);
 	for (i = 0; i < remote->url_nr; i++)
@@ -601,11 +600,9 @@ static int migrate_file(struct remote *remote)
 			return error(_("Could not append '%s' to '%s'"),
 					remote->fetch_refspec[i], buf.buf);
 	if (remote->origin == REMOTE_REMOTES)
-		path = git_path("remotes/%s", remote->name);
+		unlink_or_warn(git_path("remotes/%s", remote->name));
 	else if (remote->origin == REMOTE_BRANCHES)
-		path = git_path("branches/%s", remote->name);
-	if (path)
-		unlink_or_warn(path);
+		unlink_or_warn(git_path("branches/%s", remote->name));
 	return 0;
 }
 
diff --git a/builtin/repack.c b/builtin/repack.c
index af7340c7ba..70b9b1eaf1 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -285,8 +285,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	failed = 0;
 	for_each_string_list_item(item, &names) {
 		for (ext = 0; ext < ARRAY_SIZE(exts); ext++) {
-			const char *fname_old;
-			char *fname;
+			char *fname, *fname_old;
 			fname = mkpathdup("%s/pack-%s%s", packdir,
 						item->string, exts[ext].name);
 			if (!file_exists(fname)) {
@@ -294,7 +293,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 				continue;
 			}
 
-			fname_old = mkpath("%s/old-%s%s", packdir,
+			fname_old = mkpathdup("%s/old-%s%s", packdir,
 						item->string, exts[ext].name);
 			if (file_exists(fname_old))
 				if (unlink(fname_old))
@@ -302,10 +301,12 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 
 			if (!failed && rename(fname, fname_old)) {
 				free(fname);
+				free(fname_old);
 				failed = 1;
 				break;
 			} else {
 				string_list_append(&rollback, fname);
+				free(fname_old);
 			}
 		}
 		if (failed)
@@ -314,13 +315,13 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	if (failed) {
 		struct string_list rollback_failure = STRING_LIST_INIT_DUP;
 		for_each_string_list_item(item, &rollback) {
-			const char *fname_old;
-			char *fname;
+			char *fname, *fname_old;
 			fname = mkpathdup("%s/%s", packdir, item->string);
-			fname_old = mkpath("%s/old-%s", packdir, item->string);
+			fname_old = mkpathdup("%s/old-%s", packdir, item->string);
 			if (rename(fname_old, fname))
 				string_list_append(&rollback_failure, fname);
 			free(fname);
+			free(fname_old);
 		}
 
 		if (rollback_failure.nr) {
@@ -368,13 +369,14 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	/* Remove the "old-" files */
 	for_each_string_list_item(item, &names) {
 		for (ext = 0; ext < ARRAY_SIZE(exts); ext++) {
-			const char *fname;
-			fname = mkpath("%s/old-%s%s",
-					packdir,
-					item->string,
-					exts[ext].name);
+			char *fname;
+			fname = mkpathdup("%s/old-%s%s",
+					  packdir,
+					  item->string,
+					  exts[ext].name);
 			if (remove_path(fname))
 				warning(_("removing '%s' failed"), fname);
+			free(fname);
 		}
 	}
 
diff --git a/builtin/reset.c b/builtin/reset.c
index 4c08ddc1ca..c503e75a59 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -36,7 +36,7 @@ static const char *reset_type_names[] = {
 
 static inline int is_merge(void)
 {
-	return !access(git_path("MERGE_HEAD"), F_OK);
+	return !access(git_path_merge_head(), F_OK);
 }
 
 static int reset_index(const unsigned char *sha1, int reset_type, int quiet)