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, 58 insertions, 58 deletions

diff --git a/src/odb_loose.c b/src/odb_loose.c
index 1f8a0bb21..f0c3ac2c8 100644
--- a/src/odb_loose.c
+++ b/src/odb_loose.c
@@ -76,17 +76,17 @@ typedef struct {
  ***********************************************************/
 
 static int object_file_name(
-	git_buf *name, const loose_backend *be, const git_oid *id)
+	git_str *name, const loose_backend *be, const git_oid *id)
 {
 	size_t alloclen;
 
 	/* expand length for object root + 40 hex sha1 chars + 2 * '/' + '\0' */
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloclen, be->objects_dirlen, GIT_OID_HEXSZ);
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloclen, alloclen, 3);
-	if (git_buf_grow(name, alloclen) < 0)
+	if (git_str_grow(name, alloclen) < 0)
 		return -1;
 
-	git_buf_set(name, be->objects_dir, be->objects_dirlen);
+	git_str_set(name, be->objects_dir, be->objects_dirlen);
 	git_path_to_dir(name);
 
 	/* loose object filename: aa/aaa... (41 bytes) */
@@ -97,7 +97,7 @@ static int object_file_name(
 	return 0;
 }
 
-static int object_mkdir(const git_buf *name, const loose_backend *be)
+static int object_mkdir(const git_str *name, const loose_backend *be)
 {
 	return git_futils_mkdir_relative(
 		name->ptr + be->objects_dirlen, be->objects_dir, be->object_dir_mode,
@@ -222,9 +222,9 @@ static int is_zlib_compressed_data(unsigned char *data, size_t data_len)
  * of loose object data into packs. This format is no longer used, but
  * we must still read it.
  */
-static int read_loose_packlike(git_rawobj *out, git_buf *obj)
+static int read_loose_packlike(git_rawobj *out, git_str *obj)
 {
-	git_buf body = GIT_BUF_INIT;
+	git_str body = GIT_STR_INIT;
 	const unsigned char *obj_data;
 	obj_hdr hdr;
 	size_t obj_len, head_len, alloc_size;
@@ -253,7 +253,7 @@ static int read_loose_packlike(git_rawobj *out, git_buf *obj)
 	 * allocate a buffer and inflate the data into it
 	 */
 	if (GIT_ADD_SIZET_OVERFLOW(&alloc_size, hdr.size, 1) ||
-		git_buf_init(&body, alloc_size) < 0) {
+		git_str_init(&body, alloc_size) < 0) {
 		error = -1;
 		goto done;
 	}
@@ -263,14 +263,14 @@ static int read_loose_packlike(git_rawobj *out, git_buf *obj)
 
 	out->len = hdr.size;
 	out->type = hdr.type;
-	out->data = git_buf_detach(&body);
+	out->data = git_str_detach(&body);
 
 done:
-	git_buf_dispose(&body);
+	git_str_dispose(&body);
 	return error;
 }
 
-static int read_loose_standard(git_rawobj *out, git_buf *obj)
+static int read_loose_standard(git_rawobj *out, git_str *obj)
 {
 	git_zstream zstream = GIT_ZSTREAM_INIT;
 	unsigned char head[MAX_HEADER_LEN], *body = NULL;
@@ -279,7 +279,7 @@ static int read_loose_standard(git_rawobj *out, git_buf *obj)
 	int error;
 
 	if ((error = git_zstream_init(&zstream, GIT_ZSTREAM_INFLATE)) < 0 ||
-		(error = git_zstream_set_input(&zstream, git_buf_cstr(obj), git_buf_len(obj))) < 0)
+		(error = git_zstream_set_input(&zstream, git_str_cstr(obj), git_str_len(obj))) < 0)
 		goto done;
 
 	decompressed = sizeof(head);
@@ -339,15 +339,15 @@ done:
 	return error;
 }
 
-static int read_loose(git_rawobj *out, git_buf *loc)
+static int read_loose(git_rawobj *out, git_str *loc)
 {
 	int error;
-	git_buf obj = GIT_BUF_INIT;
+	git_str obj = GIT_STR_INIT;
 
 	GIT_ASSERT_ARG(out);
 	GIT_ASSERT_ARG(loc);
 
-	if (git_buf_oom(loc))
+	if (git_str_oom(loc))
 		return -1;
 
 	out->data = NULL;
@@ -363,7 +363,7 @@ static int read_loose(git_rawobj *out, git_buf *loc)
 		error = read_loose_standard(out, &obj);
 
 done:
-	git_buf_dispose(&obj);
+	git_str_dispose(&obj);
 	return error;
 }
 
@@ -406,7 +406,7 @@ done:
 	return error;
 }
 
-static int read_header_loose(git_rawobj *out, git_buf *loc)
+static int read_header_loose(git_rawobj *out, git_str *loc)
 {
 	unsigned char obj[1024];
 	ssize_t obj_len;
@@ -415,7 +415,7 @@ static int read_header_loose(git_rawobj *out, git_buf *loc)
 	GIT_ASSERT_ARG(out);
 	GIT_ASSERT_ARG(loc);
 
-	if (git_buf_oom(loc))
+	if (git_str_oom(loc))
 		return -1;
 
 	out->data = NULL;
@@ -446,7 +446,7 @@ done:
 }
 
 static int locate_object(
-	git_buf *object_location,
+	git_str *object_location,
 	loose_backend *backend,
 	const git_oid *oid)
 {
@@ -459,10 +459,10 @@ static int locate_object(
 }
 
 /* Explore an entry of a directory and see if it matches a short oid */
-static int fn_locate_object_short_oid(void *state, git_buf *pathbuf) {
+static int fn_locate_object_short_oid(void *state, git_str *pathbuf) {
 	loose_locate_object_state *sstate = (loose_locate_object_state *)state;
 
-	if (git_buf_len(pathbuf) - sstate->dir_len != GIT_OID_HEXSZ - 2) {
+	if (git_str_len(pathbuf) - sstate->dir_len != GIT_OID_HEXSZ - 2) {
 		/* Entry cannot be an object. Continue to next entry */
 		return 0;
 	}
@@ -491,7 +491,7 @@ static int fn_locate_object_short_oid(void *state, git_buf *pathbuf) {
 
 /* Locate an object matching a given short oid */
 static int locate_object_short_oid(
-	git_buf *object_location,
+	git_str *object_location,
 	git_oid *res_oid,
 	loose_backend *backend,
 	const git_oid *short_oid,
@@ -505,20 +505,20 @@ static int locate_object_short_oid(
 	/* prealloc memory for OBJ_DIR/xx/xx..38x..xx */
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, dir_len, GIT_OID_HEXSZ);
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 3);
-	if (git_buf_grow(object_location, alloc_len) < 0)
+	if (git_str_grow(object_location, alloc_len) < 0)
 		return -1;
 
-	git_buf_set(object_location, objects_dir, dir_len);
+	git_str_set(object_location, objects_dir, dir_len);
 	git_path_to_dir(object_location);
 
 	/* save adjusted position at end of dir so it can be restored later */
-	dir_len = git_buf_len(object_location);
+	dir_len = git_str_len(object_location);
 
 	/* Convert raw oid to hex formatted oid */
 	git_oid_fmt((char *)state.short_oid, short_oid);
 
 	/* Explore OBJ_DIR/xx/ where xx is the beginning of hex formatted short oid */
-	if (git_buf_put(object_location, (char *)state.short_oid, 3) < 0)
+	if (git_str_put(object_location, (char *)state.short_oid, 3) < 0)
 		return -1;
 	object_location->ptr[object_location->size - 1] = '/';
 
@@ -527,7 +527,7 @@ static int locate_object_short_oid(
 		return git_odb__error_notfound("no matching loose object for prefix",
 			short_oid, len);
 
-	state.dir_len = git_buf_len(object_location);
+	state.dir_len = git_str_len(object_location);
 	state.short_oid_len = len;
 	state.found = 0;
 
@@ -553,8 +553,8 @@ static int locate_object_short_oid(
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, dir_len, GIT_OID_HEXSZ);
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 2);
 
-	git_buf_truncate(object_location, dir_len);
-	if (git_buf_grow(object_location, alloc_len) < 0)
+	git_str_truncate(object_location, dir_len);
+	if (git_str_grow(object_location, alloc_len) < 0)
 		return -1;
 
 	git_oid_pathfmt(object_location->ptr + dir_len, res_oid);
@@ -583,7 +583,7 @@ static int locate_object_short_oid(
 
 static int loose_backend__read_header(size_t *len_p, git_object_t *type_p, git_odb_backend *backend, const git_oid *oid)
 {
-	git_buf object_path = GIT_BUF_INIT;
+	git_str object_path = GIT_STR_INIT;
 	git_rawobj raw;
 	int error;
 
@@ -601,14 +601,14 @@ static int loose_backend__read_header(size_t *len_p, git_object_t *type_p, git_o
 		*type_p = raw.type;
 	}
 
-	git_buf_dispose(&object_path);
+	git_str_dispose(&object_path);
 
 	return error;
 }
 
 static int loose_backend__read(void **buffer_p, size_t *len_p, git_object_t *type_p, git_odb_backend *backend, const git_oid *oid)
 {
-	git_buf object_path = GIT_BUF_INIT;
+	git_str object_path = GIT_STR_INIT;
 	git_rawobj raw;
 	int error = 0;
 
@@ -624,7 +624,7 @@ static int loose_backend__read(void **buffer_p, size_t *len_p, git_object_t *typ
 		*type_p = raw.type;
 	}
 
-	git_buf_dispose(&object_path);
+	git_str_dispose(&object_path);
 
 	return error;
 }
@@ -648,7 +648,7 @@ static int loose_backend__read_prefix(
 		if (!error)
 			git_oid_cpy(out_oid, short_oid);
 	} else {
-		git_buf object_path = GIT_BUF_INIT;
+		git_str object_path = GIT_STR_INIT;
 		git_rawobj raw;
 
 		GIT_ASSERT_ARG(backend && short_oid);
@@ -662,7 +662,7 @@ static int loose_backend__read_prefix(
 			*type_p = raw.type;
 		}
 
-		git_buf_dispose(&object_path);
+		git_str_dispose(&object_path);
 	}
 
 	return error;
@@ -670,7 +670,7 @@ static int loose_backend__read_prefix(
 
 static int loose_backend__exists(git_odb_backend *backend, const git_oid *oid)
 {
-	git_buf object_path = GIT_BUF_INIT;
+	git_str object_path = GIT_STR_INIT;
 	int error;
 
 	GIT_ASSERT_ARG(backend);
@@ -678,7 +678,7 @@ static int loose_backend__exists(git_odb_backend *backend, const git_oid *oid)
 
 	error = locate_object(&object_path, (loose_backend *)backend, oid);
 
-	git_buf_dispose(&object_path);
+	git_str_dispose(&object_path);
 
 	return !error;
 }
@@ -686,7 +686,7 @@ static int loose_backend__exists(git_odb_backend *backend, const git_oid *oid)
 static int loose_backend__exists_prefix(
 	git_oid *out, git_odb_backend *backend, const git_oid *short_id, size_t len)
 {
-	git_buf object_path = GIT_BUF_INIT;
+	git_str object_path = GIT_STR_INIT;
 	int error;
 
 	GIT_ASSERT_ARG(backend);
@@ -697,7 +697,7 @@ static int loose_backend__exists_prefix(
 	error = locate_object_short_oid(
 		&object_path, out, (loose_backend *)backend, short_id, len);
 
-	git_buf_dispose(&object_path);
+	git_str_dispose(&object_path);
 
 	return error;
 }
@@ -736,7 +736,7 @@ GIT_INLINE(int) filename_to_oid(git_oid *oid, const char *ptr)
 	return 0;
 }
 
-static int foreach_object_dir_cb(void *_state, git_buf *path)
+static int foreach_object_dir_cb(void *_state, git_str *path)
 {
 	git_oid oid;
 	struct foreach_state *state = (struct foreach_state *) _state;
@@ -748,12 +748,12 @@ static int foreach_object_dir_cb(void *_state, git_buf *path)
 		state->cb(&oid, state->data), "git_odb_foreach");
 }
 
-static int foreach_cb(void *_state, git_buf *path)
+static int foreach_cb(void *_state, git_str *path)
 {
 	struct foreach_state *state = (struct foreach_state *) _state;
 
 	/* non-dir is some stray file, ignore it */
-	if (!git_path_isdir(git_buf_cstr(path)))
+	if (!git_path_isdir(git_str_cstr(path)))
 		return 0;
 
 	return git_path_direach(path, 0, foreach_object_dir_cb, state);
@@ -763,7 +763,7 @@ static int loose_backend__foreach(git_odb_backend *_backend, git_odb_foreach_cb
 {
 	char *objects_dir;
 	int error;
-	git_buf buf = GIT_BUF_INIT;
+	git_str buf = GIT_STR_INIT;
 	struct foreach_state state;
 	loose_backend *backend = (loose_backend *) _backend;
 
@@ -772,19 +772,19 @@ static int loose_backend__foreach(git_odb_backend *_backend, git_odb_foreach_cb
 
 	objects_dir = backend->objects_dir;
 
-	git_buf_sets(&buf, objects_dir);
+	git_str_sets(&buf, objects_dir);
 	git_path_to_dir(&buf);
-	if (git_buf_oom(&buf))
+	if (git_str_oom(&buf))
 		return -1;
 
 	memset(&state, 0, sizeof(state));
 	state.cb = cb;
 	state.data = data;
-	state.dir_len = git_buf_len(&buf);
+	state.dir_len = git_str_len(&buf);
 
 	error = git_path_direach(&buf, 0, foreach_cb, &state);
 
-	git_buf_dispose(&buf);
+	git_str_dispose(&buf);
 
 	return error;
 }
@@ -793,7 +793,7 @@ static int loose_backend__writestream_finalize(git_odb_stream *_stream, const gi
 {
 	loose_writestream *stream = (loose_writestream *)_stream;
 	loose_backend *backend = (loose_backend *)_stream->backend;
-	git_buf final_path = GIT_BUF_INIT;
+	git_str final_path = GIT_STR_INIT;
 	int error = 0;
 
 	if (object_file_name(&final_path, backend, oid) < 0 ||
@@ -803,7 +803,7 @@ static int loose_backend__writestream_finalize(git_odb_stream *_stream, const gi
 		error = git_filebuf_commit_at(
 			&stream->fbuf, final_path.ptr);
 
-	git_buf_dispose(&final_path);
+	git_str_dispose(&final_path);
 
 	return error;
 }
@@ -838,7 +838,7 @@ static int loose_backend__writestream(git_odb_stream **stream_out, git_odb_backe
 	loose_backend *backend;
 	loose_writestream *stream = NULL;
 	char hdr[MAX_HEADER_LEN];
-	git_buf tmp_path = GIT_BUF_INIT;
+	git_str tmp_path = GIT_STR_INIT;
 	size_t hdrlen;
 	int error;
 
@@ -861,7 +861,7 @@ static int loose_backend__writestream(git_odb_stream **stream_out, git_odb_backe
 	stream->stream.free = &loose_backend__writestream_free;
 	stream->stream.mode = GIT_STREAM_WRONLY;
 
-	if (git_buf_joinpath(&tmp_path, backend->objects_dir, "tmp_object") < 0 ||
+	if (git_str_joinpath(&tmp_path, backend->objects_dir, "tmp_object") < 0 ||
 		git_filebuf_open(&stream->fbuf, tmp_path.ptr, filebuf_flags(backend),
 			backend->object_file_mode) < 0 ||
 		stream->stream.write((git_odb_stream *)stream, hdr, hdrlen) < 0)
@@ -870,7 +870,7 @@ static int loose_backend__writestream(git_odb_stream **stream_out, git_odb_backe
 		git__free(stream);
 		stream = NULL;
 	}
-	git_buf_dispose(&tmp_path);
+	git_str_dispose(&tmp_path);
 	*stream_out = (git_odb_stream *)stream;
 
 	return !stream ? -1 : 0;
@@ -996,7 +996,7 @@ static int loose_backend__readstream(
 	loose_backend *backend;
 	loose_readstream *stream = NULL;
 	git_hash_ctx *hash_ctx = NULL;
-	git_buf object_path = GIT_BUF_INIT;
+	git_str object_path = GIT_STR_INIT;
 	obj_hdr hdr;
 	int error = 0;
 
@@ -1059,14 +1059,14 @@ done:
 		}
 	}
 
-	git_buf_dispose(&object_path);
+	git_str_dispose(&object_path);
 	return error;
 }
 
 static int loose_backend__write(git_odb_backend *_backend, const git_oid *oid, const void *data, size_t len, git_object_t type)
 {
 	int error = 0;
-	git_buf final_path = GIT_BUF_INIT;
+	git_str final_path = GIT_STR_INIT;
 	char header[MAX_HEADER_LEN];
 	size_t header_len;
 	git_filebuf fbuf = GIT_FILEBUF_INIT;
@@ -1079,7 +1079,7 @@ static int loose_backend__write(git_odb_backend *_backend, const git_oid *oid, c
 		header, sizeof(header), len, type)) < 0)
 		goto cleanup;
 
-	if (git_buf_joinpath(&final_path, backend->objects_dir, "tmp_object") < 0 ||
+	if (git_str_joinpath(&final_path, backend->objects_dir, "tmp_object") < 0 ||
 		git_filebuf_open(&fbuf, final_path.ptr, filebuf_flags(backend),
 			backend->object_file_mode) < 0)
 	{
@@ -1098,7 +1098,7 @@ static int loose_backend__write(git_odb_backend *_backend, const git_oid *oid, c
 cleanup:
 	if (error < 0)
 		git_filebuf_cleanup(&fbuf);
-	git_buf_dispose(&final_path);
+	git_str_dispose(&final_path);
 	return error;
 }
 
@@ -1107,14 +1107,14 @@ static int loose_backend__freshen(
 	const git_oid *oid)
 {
 	loose_backend *backend = (loose_backend *)_backend;
-	git_buf path = GIT_BUF_INIT;
+	git_str path = GIT_STR_INIT;
 	int error;
 
 	if (object_file_name(&path, backend, oid) < 0)
 		return -1;
 
 	error = git_futils_touch(path.ptr, NULL);
-	git_buf_dispose(&path);
+	git_str_dispose(&path);
 
 	return error;
 }