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, 17 insertions, 17 deletions

diff --git a/src/filebuf.c b/src/filebuf.c
index 4296b2226..10f8c5813 100644
--- a/src/filebuf.c
+++ b/src/filebuf.c
@@ -195,21 +195,21 @@ static int write_deflate(git_filebuf *file, void *source, size_t len)
 
 #define MAX_SYMLINK_DEPTH 5
 
-static int resolve_symlink(git_buf *out, const char *path)
+static int resolve_symlink(git_str *out, const char *path)
 {
 	int i, error, root;
 	ssize_t ret;
 	struct stat st;
-	git_buf curpath = GIT_BUF_INIT, target = GIT_BUF_INIT;
+	git_str curpath = GIT_STR_INIT, target = GIT_STR_INIT;
 
-	if ((error = git_buf_grow(&target, GIT_PATH_MAX + 1)) < 0 ||
-	    (error = git_buf_puts(&curpath, path)) < 0)
+	if ((error = git_str_grow(&target, GIT_PATH_MAX + 1)) < 0 ||
+	    (error = git_str_puts(&curpath, path)) < 0)
 		return error;
 
 	for (i = 0; i < MAX_SYMLINK_DEPTH; i++) {
 		error = p_lstat(curpath.ptr, &st);
 		if (error < 0 && errno == ENOENT) {
-			error = git_buf_puts(out, curpath.ptr);
+			error = git_str_puts(out, curpath.ptr);
 			goto cleanup;
 		}
 
@@ -220,7 +220,7 @@ static int resolve_symlink(git_buf *out, const char *path)
 		}
 
 		if (!S_ISLNK(st.st_mode)) {
-			error = git_buf_puts(out, curpath.ptr);
+			error = git_str_puts(out, curpath.ptr);
 			goto cleanup;
 		}
 
@@ -243,16 +243,16 @@ static int resolve_symlink(git_buf *out, const char *path)
 
 		root = git_path_root(target.ptr);
 		if (root >= 0) {
-			if ((error = git_buf_sets(&curpath, target.ptr)) < 0)
+			if ((error = git_str_sets(&curpath, target.ptr)) < 0)
 				goto cleanup;
 		} else {
-			git_buf dir = GIT_BUF_INIT;
+			git_str dir = GIT_STR_INIT;
 
 			if ((error = git_path_dirname_r(&dir, curpath.ptr)) < 0)
 				goto cleanup;
 
-			git_buf_swap(&curpath, &dir);
-			git_buf_dispose(&dir);
+			git_str_swap(&curpath, &dir);
+			git_str_dispose(&dir);
 
 			if ((error = git_path_apply_relative(&curpath, target.ptr)) < 0)
 				goto cleanup;
@@ -263,8 +263,8 @@ static int resolve_symlink(git_buf *out, const char *path)
 	error = -1;
 
 cleanup:
-	git_buf_dispose(&curpath);
-	git_buf_dispose(&target);
+	git_str_dispose(&curpath);
+	git_str_dispose(&target);
 	return error;
 }
 
@@ -332,13 +332,13 @@ int git_filebuf_open_withsize(git_filebuf *file, const char *path, int flags, mo
 
 	/* If we are writing to a temp file */
 	if (flags & GIT_FILEBUF_TEMPORARY) {
-		git_buf tmp_path = GIT_BUF_INIT;
+		git_str tmp_path = GIT_STR_INIT;
 
 		/* Open the file as temporary for locking */
 		file->fd = git_futils_mktmp(&tmp_path, path, mode);
 
 		if (file->fd < 0) {
-			git_buf_dispose(&tmp_path);
+			git_str_dispose(&tmp_path);
 			goto cleanup;
 		}
 		file->fd_is_open = true;
@@ -346,17 +346,17 @@ int git_filebuf_open_withsize(git_filebuf *file, const char *path, int flags, mo
 
 		/* No original path */
 		file->path_original = NULL;
-		file->path_lock = git_buf_detach(&tmp_path);
+		file->path_lock = git_str_detach(&tmp_path);
 		GIT_ERROR_CHECK_ALLOC(file->path_lock);
 	} else {
-		git_buf resolved_path = GIT_BUF_INIT;
+		git_str resolved_path = GIT_STR_INIT;
 
 		if ((error = resolve_symlink(&resolved_path, path)) < 0)
 			goto cleanup;
 
 		/* Save the original path of the file */
 		path_len = resolved_path.size;
-		file->path_original = git_buf_detach(&resolved_path);
+		file->path_original = git_str_detach(&resolved_path);
 
 		/* create the locking path by appending ".lock" to the original */
 		GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, path_len, GIT_FILELOCK_EXTLENGTH);