str: introduce `git_str` for internal, `git_buf` is externalethomson/gitstr

libgit2 has two distinct requirements that were previously solved by
`git_buf`.  We require:

1. A general purpose string class that provides a number of utility APIs
   for manipulating data (eg, concatenating, truncating, etc).
2. A structure that we can use to return strings to callers that they
   can take ownership of.

By using a single class (`git_buf`) for both of these purposes, we have
confused the API to the point that refactorings are difficult and
reasoning about correctness is also difficult.

Move the utility class `git_buf` to be called `git_str`: this represents
its general purpose, as an internal string buffer class.  The name also
is an homage to Junio Hamano ("gitstr").

The public API remains `git_buf`, and has a much smaller footprint.  It
is generally only used as an "out" param with strict requirements that
follow the documentation.  (Exceptions exist for some legacy APIs to
avoid breaking callers unnecessarily.)

Utility functions exist to convert a user-specified `git_buf` to a
`git_str` so that we can call internal functions, then converting it
back again.

1 files changed, 40 insertions, 40 deletions

diff --git a/src/odb_pack.c b/src/odb_pack.c
index f4cb9a558..f2c47adbe 100644
--- a/src/odb_pack.c
+++ b/src/odb_pack.c
@@ -166,7 +166,7 @@ struct pack_writepack {
 
 static int packfile_sort__cb(const void *a_, const void *b_);
 
-static int packfile_load__cb(void *_data, git_buf *path);
+static int packfile_load__cb(void *_data, git_str *path);
 
 static int packfile_byname_search_cmp(const void *path, const void *pack_entry);
 
@@ -195,10 +195,10 @@ static int pack_entry_find_prefix(
 
 static int packfile_byname_search_cmp(const void *path_, const void *p_)
 {
-	const git_buf *path = (const git_buf *)path_;
+	const git_str *path = (const git_str *)path_;
 	const struct git_pack_file *p = (const struct git_pack_file *)p_;
 
-	return strncmp(p->pack_name, git_buf_cstr(path), git_buf_len(path));
+	return strncmp(p->pack_name, git_str_cstr(path), git_str_len(path));
 }
 
 static int packfile_sort__cb(const void *a_, const void *b_)
@@ -231,20 +231,20 @@ static int packfile_sort__cb(const void *a_, const void *b_)
 }
 
 
-static int packfile_load__cb(void *data, git_buf *path)
+static int packfile_load__cb(void *data, git_str *path)
 {
 	struct pack_backend *backend = data;
 	struct git_pack_file *pack;
-	const char *path_str = git_buf_cstr(path);
-	git_buf index_prefix = GIT_BUF_INIT;
-	size_t cmp_len = git_buf_len(path);
+	const char *path_str = git_str_cstr(path);
+	git_str index_prefix = GIT_STR_INIT;
+	size_t cmp_len = git_str_len(path);
 	int error;
 
 	if (cmp_len <= strlen(".idx") || git__suffixcmp(path_str, ".idx") != 0)
 		return 0; /* not an index */
 
 	cmp_len -= strlen(".idx");
-	git_buf_attach_notowned(&index_prefix, path_str, cmp_len);
+	git_str_attach_notowned(&index_prefix, path_str, cmp_len);
 
 	if (git_vector_search2(NULL, &backend->midx_packs, packfile_byname_search_cmp, &index_prefix) == 0)
 		return 0;
@@ -404,29 +404,29 @@ static int process_multi_pack_index_pack(
 	int error;
 	struct git_pack_file *pack;
 	size_t found_position;
-	git_buf pack_path = GIT_BUF_INIT, index_prefix = GIT_BUF_INIT;
+	git_str pack_path = GIT_STR_INIT, index_prefix = GIT_STR_INIT;
 
-	error = git_buf_joinpath(&pack_path, backend->pack_folder, packfile_name);
+	error = git_str_joinpath(&pack_path, backend->pack_folder, packfile_name);
 	if (error < 0)
 		return error;
 
 	/* This is ensured by midx_parse_packfile_name() */
-	if (git_buf_len(&pack_path) <= strlen(".idx") || git__suffixcmp(git_buf_cstr(&pack_path), ".idx") != 0)
+	if (git_str_len(&pack_path) <= strlen(".idx") || git__suffixcmp(git_str_cstr(&pack_path), ".idx") != 0)
 		return git_odb__error_notfound("midx file contained a non-index", NULL, 0);
 
-	git_buf_attach_notowned(&index_prefix, git_buf_cstr(&pack_path), git_buf_len(&pack_path) - strlen(".idx"));
+	git_str_attach_notowned(&index_prefix, git_str_cstr(&pack_path), git_str_len(&pack_path) - strlen(".idx"));
 
 	if (git_vector_search2(&found_position, &backend->packs, packfile_byname_search_cmp, &index_prefix) == 0) {
 		/* Pack was found in the packs list. Moving it to the midx_packs list. */
-		git_buf_dispose(&pack_path);
+		git_str_dispose(&pack_path);
 		git_vector_set(NULL, &backend->midx_packs, i, git_vector_get(&backend->packs, found_position));
 		git_vector_remove(&backend->packs, found_position);
 		return 0;
 	}
 
 	/* Pack was not found. Allocate a new one. */
-	error = git_mwindow_get_pack(&pack, git_buf_cstr(&pack_path));
-	git_buf_dispose(&pack_path);
+	error = git_mwindow_get_pack(&pack, git_str_cstr(&pack_path));
+	git_str_dispose(&pack_path);
 	if (error < 0)
 		return error;
 
@@ -442,11 +442,11 @@ static int process_multi_pack_index_pack(
 static int refresh_multi_pack_index(struct pack_backend *backend)
 {
 	int error;
-	git_buf midx_path = GIT_BUF_INIT;
+	git_str midx_path = GIT_STR_INIT;
 	const char *packfile_name;
 	size_t i;
 
-	error = git_buf_joinpath(&midx_path, backend->pack_folder, "multi-pack-index");
+	error = git_str_joinpath(&midx_path, backend->pack_folder, "multi-pack-index");
 	if (error < 0)
 		return error;
 
@@ -457,19 +457,19 @@ static int refresh_multi_pack_index(struct pack_backend *backend)
 	 * refreshing the new multi-pack-index fails, or the file is deleted.
 	 */
 	if (backend->midx) {
-		if (!git_midx_needs_refresh(backend->midx, git_buf_cstr(&midx_path))) {
-			git_buf_dispose(&midx_path);
+		if (!git_midx_needs_refresh(backend->midx, git_str_cstr(&midx_path))) {
+			git_str_dispose(&midx_path);
 			return 0;
 		}
 		error = remove_multi_pack_index(backend);
 		if (error < 0) {
-			git_buf_dispose(&midx_path);
+			git_str_dispose(&midx_path);
 			return error;
 		}
 	}
 
-	error = git_midx_open(&backend->midx, git_buf_cstr(&midx_path));
-	git_buf_dispose(&midx_path);
+	error = git_midx_open(&backend->midx, git_str_cstr(&midx_path));
+	git_str_dispose(&midx_path);
 	if (error < 0)
 		return error;
 
@@ -505,7 +505,7 @@ static int pack_backend__refresh(git_odb_backend *backend_)
 {
 	int error;
 	struct stat st;
-	git_buf path = GIT_BUF_INIT;
+	git_str path = GIT_STR_INIT;
 	struct pack_backend *backend = (struct pack_backend *)backend_;
 
 	if (backend->pack_folder == NULL)
@@ -523,10 +523,10 @@ static int pack_backend__refresh(git_odb_backend *backend_)
 	}
 
 	/* reload all packs */
-	git_buf_sets(&path, backend->pack_folder);
+	git_str_sets(&path, backend->pack_folder);
 	error = git_path_direach(&path, 0, packfile_load__cb, backend);
 
-	git_buf_dispose(&path);
+	git_str_dispose(&path);
 	git_vector_sort(&backend->packs);
 
 	return error;
@@ -743,7 +743,7 @@ static int pack_backend__writepack(struct git_odb_writepack **out,
 }
 
 static int get_idx_path(
-		git_buf *idx_path,
+		git_str *idx_path,
 		struct pack_backend *backend,
 		struct git_pack_file *p)
 {
@@ -753,11 +753,11 @@ static int get_idx_path(
 	error = git_path_prettify(idx_path, p->pack_name, backend->pack_folder);
 	if (error < 0)
 		return error;
-	path_len = git_buf_len(idx_path);
-	if (path_len <= strlen(".pack") || git__suffixcmp(git_buf_cstr(idx_path), ".pack") != 0)
+	path_len = git_str_len(idx_path);
+	if (path_len <= strlen(".pack") || git__suffixcmp(git_str_cstr(idx_path), ".pack") != 0)
 		return git_odb__error_notfound("packfile does not end in .pack", NULL, 0);
 	path_len -= strlen(".pack");
-	error = git_buf_splice(idx_path, path_len, strlen(".pack"), ".idx", strlen(".idx"));
+	error = git_str_splice(idx_path, path_len, strlen(".pack"), ".idx", strlen(".idx"));
 	if (error < 0)
 		return error;
 
@@ -781,22 +781,22 @@ static int pack_backend__writemidx(git_odb_backend *_backend)
 		return error;
 
 	git_vector_foreach(&backend->midx_packs, i, p) {
-		git_buf idx_path = GIT_BUF_INIT;
+		git_str idx_path = GIT_STR_INIT;
 		error = get_idx_path(&idx_path, backend, p);
 		if (error < 0)
 			goto cleanup;
-		error = git_midx_writer_add(w, git_buf_cstr(&idx_path));
-		git_buf_dispose(&idx_path);
+		error = git_midx_writer_add(w, git_str_cstr(&idx_path));
+		git_str_dispose(&idx_path);
 		if (error < 0)
 			goto cleanup;
 	}
 	git_vector_foreach(&backend->packs, i, p) {
-		git_buf idx_path = GIT_BUF_INIT;
+		git_str idx_path = GIT_STR_INIT;
 		error = get_idx_path(&idx_path, backend, p);
 		if (error < 0)
 			goto cleanup;
-		error = git_midx_writer_add(w, git_buf_cstr(&idx_path));
-		git_buf_dispose(&idx_path);
+		error = git_midx_writer_add(w, git_str_cstr(&idx_path));
+		git_str_dispose(&idx_path);
 		if (error < 0)
 			goto cleanup;
 	}
@@ -896,15 +896,15 @@ int git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir)
 {
 	int error = 0;
 	struct pack_backend *backend = NULL;
-	git_buf path = GIT_BUF_INIT;
+	git_str path = GIT_STR_INIT;
 
 	if (pack_backend__alloc(&backend, 8) < 0)
 		return -1;
 
-	if (!(error = git_buf_joinpath(&path, objects_dir, "pack")) &&
-		git_path_isdir(git_buf_cstr(&path)))
+	if (!(error = git_str_joinpath(&path, objects_dir, "pack")) &&
+		git_path_isdir(git_str_cstr(&path)))
 	{
-		backend->pack_folder = git_buf_detach(&path);
+		backend->pack_folder = git_str_detach(&path);
 		error = pack_backend__refresh((git_odb_backend *)backend);
 	}
 
@@ -915,7 +915,7 @@ int git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir)
 
 	*backend_out = (git_odb_backend *)backend;
 
-	git_buf_dispose(&path);
+	git_str_dispose(&path);
 
 	return error;
 }