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, 16 insertions, 16 deletions

diff --git a/tests/merge/merge_helpers.c b/tests/merge/merge_helpers.c
index 27f355f35..1eb423ef7 100644
--- a/tests/merge/merge_helpers.c
+++ b/tests/merge/merge_helpers.c
@@ -17,15 +17,15 @@ int merge_trees_from_branches(
 	git_commit *our_commit, *their_commit, *ancestor_commit = NULL;
 	git_tree *our_tree, *their_tree, *ancestor_tree = NULL;
 	git_oid our_oid, their_oid, ancestor_oid;
-	git_buf branch_buf = GIT_BUF_INIT;
+	git_str branch_buf = GIT_STR_INIT;
 	int error;
 
-	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours_name);
+	git_str_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours_name);
 	cl_git_pass(git_reference_name_to_id(&our_oid, repo, branch_buf.ptr));
 	cl_git_pass(git_commit_lookup(&our_commit, repo, &our_oid));
 
-	git_buf_clear(&branch_buf);
-	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, theirs_name);
+	git_str_clear(&branch_buf);
+	git_str_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, theirs_name);
 	cl_git_pass(git_reference_name_to_id(&their_oid, repo, branch_buf.ptr));
 	cl_git_pass(git_commit_lookup(&their_commit, repo, &their_oid));
 
@@ -43,7 +43,7 @@ int merge_trees_from_branches(
 
 	error = git_merge_trees(index, repo, ancestor_tree, our_tree, their_tree, opts);
 
-	git_buf_dispose(&branch_buf);
+	git_str_dispose(&branch_buf);
 	git_tree_free(our_tree);
 	git_tree_free(their_tree);
 	git_tree_free(ancestor_tree);
@@ -61,21 +61,21 @@ int merge_commits_from_branches(
 {
 	git_commit *our_commit, *their_commit;
 	git_oid our_oid, their_oid;
-	git_buf branch_buf = GIT_BUF_INIT;
+	git_str branch_buf = GIT_STR_INIT;
 	int error;
 
-	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours_name);
+	git_str_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours_name);
 	cl_git_pass(git_reference_name_to_id(&our_oid, repo, branch_buf.ptr));
 	cl_git_pass(git_commit_lookup(&our_commit, repo, &our_oid));
 
-	git_buf_clear(&branch_buf);
-	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, theirs_name);
+	git_str_clear(&branch_buf);
+	git_str_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, theirs_name);
 	cl_git_pass(git_reference_name_to_id(&their_oid, repo, branch_buf.ptr));
 	cl_git_pass(git_commit_lookup(&their_commit, repo, &their_oid));
 
 	error = git_merge_commits(index, repo, our_commit, their_commit, opts);
 
-	git_buf_dispose(&branch_buf);
+	git_str_dispose(&branch_buf);
 	git_commit_free(our_commit);
 	git_commit_free(their_commit);
 
@@ -328,12 +328,12 @@ int merge_test_reuc(git_index *index, const struct merge_reuc_entry expected[],
 	return 1;
 }
 
-int dircount(void *payload, git_buf *pathbuf)
+int dircount(void *payload, git_str *pathbuf)
 {
 	size_t *entries = payload;
-	size_t len = git_buf_len(pathbuf);
+	size_t len = git_str_len(pathbuf);
 
-	if (len < 5 || strcmp(pathbuf->ptr + (git_buf_len(pathbuf) - 5), "/.git") != 0)
+	if (len < 5 || strcmp(pathbuf->ptr + (git_str_len(pathbuf) - 5), "/.git") != 0)
 		(*entries)++;
 
 	return 0;
@@ -343,9 +343,9 @@ int merge_test_workdir(git_repository *repo, const struct merge_index_entry expe
 {
 	size_t actual_len = 0, i;
 	git_oid actual_oid, expected_oid;
-	git_buf wd = GIT_BUF_INIT;
+	git_str wd = GIT_STR_INIT;
 
-	git_buf_puts(&wd, repo->workdir);
+	git_str_puts(&wd, repo->workdir);
 	git_path_direach(&wd, 0, dircount, &actual_len);
 
 	if (actual_len != expected_len)
@@ -359,7 +359,7 @@ int merge_test_workdir(git_repository *repo, const struct merge_index_entry expe
 			return 0;
 	}
 
-	git_buf_dispose(&wd);
+	git_str_dispose(&wd);
 
 	return 1;
 }