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, 19 insertions, 19 deletions

diff --git a/src/merge.c b/src/merge.c
index d838e4ba9..ae1d453ec 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -8,7 +8,7 @@
 #include "merge.h"
 
 #include "posix.h"
-#include "buffer.h"
+#include "str.h"
 #include "repository.h"
 #include "revwalk.h"
 #include "commit_list.h"
@@ -591,7 +591,7 @@ int git_repository_mergehead_foreach(
 	git_repository_mergehead_foreach_cb cb,
 	void *payload)
 {
-	git_buf merge_head_path = GIT_BUF_INIT, merge_head_file = GIT_BUF_INIT;
+	git_str merge_head_path = GIT_STR_INIT, merge_head_file = GIT_STR_INIT;
 	char *buffer, *line;
 	size_t line_num = 1;
 	git_oid oid;
@@ -600,12 +600,12 @@ int git_repository_mergehead_foreach(
 	GIT_ASSERT_ARG(repo);
 	GIT_ASSERT_ARG(cb);
 
-	if ((error = git_buf_joinpath(&merge_head_path, repo->gitdir,
+	if ((error = git_str_joinpath(&merge_head_path, repo->gitdir,
 		GIT_MERGE_HEAD_FILE)) < 0)
 		return error;
 
 	if ((error = git_futils_readbuffer(&merge_head_file,
-		git_buf_cstr(&merge_head_path))) < 0)
+		git_str_cstr(&merge_head_path))) < 0)
 		goto cleanup;
 
 	buffer = merge_head_file.ptr;
@@ -635,8 +635,8 @@ int git_repository_mergehead_foreach(
 	}
 
 cleanup:
-	git_buf_dispose(&merge_head_path);
-	git_buf_dispose(&merge_head_file);
+	git_str_dispose(&merge_head_path);
+	git_str_dispose(&merge_head_file);
 
 	return error;
 }
@@ -893,7 +893,7 @@ static int merge_conflict_invoke_driver(
 	git_merge_driver_source *src)
 {
 	git_index_entry *result;
-	git_buf buf = GIT_BUF_INIT;
+	git_buf buf = {0};
 	const char *path;
 	uint32_t mode;
 	git_odb *odb = NULL;
@@ -2473,14 +2473,14 @@ static int write_merge_head(
 	size_t heads_len)
 {
 	git_filebuf file = GIT_FILEBUF_INIT;
-	git_buf file_path = GIT_BUF_INIT;
+	git_str file_path = GIT_STR_INIT;
 	size_t i;
 	int error = 0;
 
 	GIT_ASSERT_ARG(repo);
 	GIT_ASSERT_ARG(heads);
 
-	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_HEAD_FILE)) < 0 ||
+	if ((error = git_str_joinpath(&file_path, repo->gitdir, GIT_MERGE_HEAD_FILE)) < 0 ||
 		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_CREATE_LEADING_DIRS, GIT_MERGE_FILE_MODE)) < 0)
 		goto cleanup;
 
@@ -2495,7 +2495,7 @@ cleanup:
 	if (error < 0)
 		git_filebuf_cleanup(&file);
 
-	git_buf_dispose(&file_path);
+	git_str_dispose(&file_path);
 
 	return error;
 }
@@ -2503,12 +2503,12 @@ cleanup:
 static int write_merge_mode(git_repository *repo)
 {
 	git_filebuf file = GIT_FILEBUF_INIT;
-	git_buf file_path = GIT_BUF_INIT;
+	git_str file_path = GIT_STR_INIT;
 	int error = 0;
 
 	GIT_ASSERT_ARG(repo);
 
-	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_MODE_FILE)) < 0 ||
+	if ((error = git_str_joinpath(&file_path, repo->gitdir, GIT_MERGE_MODE_FILE)) < 0 ||
 		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_CREATE_LEADING_DIRS, GIT_MERGE_FILE_MODE)) < 0)
 		goto cleanup;
 
@@ -2521,7 +2521,7 @@ cleanup:
 	if (error < 0)
 		git_filebuf_cleanup(&file);
 
-	git_buf_dispose(&file_path);
+	git_str_dispose(&file_path);
 
 	return error;
 }
@@ -2719,7 +2719,7 @@ static int write_merge_msg(
 	size_t heads_len)
 {
 	git_filebuf file = GIT_FILEBUF_INIT;
-	git_buf file_path = GIT_BUF_INIT;
+	git_str file_path = GIT_STR_INIT;
 	struct merge_msg_entry *entries;
 	git_vector matching = GIT_VECTOR_INIT;
 	size_t i;
@@ -2740,7 +2740,7 @@ static int write_merge_msg(
 	for (i = 0; i < heads_len; i++)
 		entries[i].merge_head = heads[i];
 
-	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_MSG_FILE)) < 0 ||
+	if ((error = git_str_joinpath(&file_path, repo->gitdir, GIT_MERGE_MSG_FILE)) < 0 ||
 		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_CREATE_LEADING_DIRS, GIT_MERGE_FILE_MODE)) < 0 ||
 		(error = git_filebuf_write(&file, "Merge ", 6)) < 0)
 		goto cleanup;
@@ -2822,7 +2822,7 @@ cleanup:
 	if (error < 0)
 		git_filebuf_cleanup(&file);
 
-	git_buf_dispose(&file_path);
+	git_str_dispose(&file_path);
 
 	git_vector_free(&matching);
 	git__free(entries);
@@ -3114,7 +3114,7 @@ int git_merge__append_conflicts_to_merge_msg(
 	git_index *index)
 {
 	git_filebuf file = GIT_FILEBUF_INIT;
-	git_buf file_path = GIT_BUF_INIT;
+	git_str file_path = GIT_STR_INIT;
 	const char *last = NULL;
 	size_t i;
 	int error;
@@ -3122,7 +3122,7 @@ int git_merge__append_conflicts_to_merge_msg(
 	if (!git_index_has_conflicts(index))
 		return 0;
 
-	if ((error = git_buf_joinpath(&file_path, repo->gitdir, GIT_MERGE_MSG_FILE)) < 0 ||
+	if ((error = git_str_joinpath(&file_path, repo->gitdir, GIT_MERGE_MSG_FILE)) < 0 ||
 		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_APPEND, GIT_MERGE_FILE_MODE)) < 0)
 		goto cleanup;
 
@@ -3146,7 +3146,7 @@ cleanup:
 	if (error < 0)
 		git_filebuf_cleanup(&file);
 
-	git_buf_dispose(&file_path);
+	git_str_dispose(&file_path);
 
 	return error;
 }