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, 20 insertions, 29 deletions

diff --git a/src/notes.c b/src/notes.c
index 95db334fb..d1a2b0f64 100644
--- a/src/notes.c
+++ b/src/notes.c
@@ -7,7 +7,7 @@
 
 #include "notes.h"
 
-#include "git2.h"
+#include "buf.h"
 #include "refs.h"
 #include "config.h"
 #include "iterator.h"
@@ -407,7 +407,7 @@ cleanup:
 	return error;
 }
 
-static int note_get_default_ref(git_buf *out, git_repository *repo)
+static int note_get_default_ref(git_str *out, git_repository *repo)
 {
 	git_config *cfg;
 	int error;
@@ -415,25 +415,25 @@ static int note_get_default_ref(git_buf *out, git_repository *repo)
 	if ((error = git_repository_config__weakptr(&cfg, repo)) < 0)
 		return error;
 
-	error = git_config_get_string_buf(out, cfg, "core.notesref");
+	error = git_config__get_string_buf(out, cfg, "core.notesref");
 
 	if (error == GIT_ENOTFOUND)
-		error = git_buf_puts(out, GIT_NOTES_DEFAULT_REF);
+		error = git_str_puts(out, GIT_NOTES_DEFAULT_REF);
 
 	return error;
 }
 
-static int normalize_namespace(git_buf *out, git_repository *repo, const char *notes_ref)
+static int normalize_namespace(git_str *out, git_repository *repo, const char *notes_ref)
 {
 	if (notes_ref)
-		return git_buf_puts(out, notes_ref);
+		return git_str_puts(out, notes_ref);
 
 	return note_get_default_ref(out, repo);
 }
 
 static int retrieve_note_commit(
 	git_commit **commit_out,
-	git_buf *notes_ref_out,
+	git_str *notes_ref_out,
 	git_repository *repo,
 	const char *notes_ref)
 {
@@ -478,7 +478,7 @@ int git_note_read(git_note **out, git_repository *repo,
 		  const char *notes_ref_in, const git_oid *oid)
 {
 	int error;
-	git_buf notes_ref = GIT_BUF_INIT;
+	git_str notes_ref = GIT_STR_INIT;
 	git_commit *commit = NULL;
 
 	error = retrieve_note_commit(&commit, &notes_ref, repo, notes_ref_in);
@@ -489,7 +489,7 @@ int git_note_read(git_note **out, git_repository *repo,
 	error = git_note_commit_read(out, repo, commit, oid);
 
 cleanup:
-	git_buf_dispose(&notes_ref);
+	git_str_dispose(&notes_ref);
 	git_commit_free(commit);
 	return error;
 }
@@ -536,7 +536,7 @@ int git_note_create(
 	int allow_note_overwrite)
 {
 	int error;
-	git_buf notes_ref = GIT_BUF_INIT;
+	git_str notes_ref = GIT_STR_INIT;
 	git_commit *existing_notes_commit = NULL;
 	git_reference *ref = NULL;
 	git_oid notes_blob_oid, notes_commit_oid;
@@ -562,7 +562,7 @@ int git_note_create(
 		git_oid_cpy(out, &notes_blob_oid);
 
 cleanup:
-	git_buf_dispose(&notes_ref);
+	git_str_dispose(&notes_ref);
 	git_commit_free(existing_notes_commit);
 	git_reference_free(ref);
 	return error;
@@ -598,7 +598,7 @@ int git_note_remove(git_repository *repo, const char *notes_ref_in,
 		const git_oid *oid)
 {
 	int error;
-	git_buf notes_ref_target = GIT_BUF_INIT;
+	git_str notes_ref_target = GIT_STR_INIT;
 	git_commit *existing_notes_commit = NULL;
 	git_oid new_notes_commit;
 	git_reference *notes_ref = NULL;
@@ -618,7 +618,7 @@ int git_note_remove(git_repository *repo, const char *notes_ref_in,
 			&new_notes_commit, 1, NULL);
 
 cleanup:
-	git_buf_dispose(&notes_ref_target);
+	git_str_dispose(&notes_ref_target);
 	git_reference_free(notes_ref);
 	git_commit_free(existing_notes_commit);
 	return error;
@@ -626,16 +626,7 @@ cleanup:
 
 int git_note_default_ref(git_buf *out, git_repository *repo)
 {
-	int error;
-
-	GIT_ASSERT_ARG(out);
-	GIT_ASSERT_ARG(repo);
-
-	if ((error = git_buf_sanitize(out)) < 0 ||
-	    (error = note_get_default_ref(out, repo)) < 0)
-		git_buf_dispose(out);
-
-	return error;
+	GIT_BUF_WRAP_PRIVATE(out, note_get_default_ref, repo);
 }
 
 const git_signature *git_note_committer(const git_note *note)
@@ -679,12 +670,12 @@ static int process_entry_path(
 {
 	int error = 0;
 	size_t i = 0, j = 0, len;
-	git_buf buf = GIT_BUF_INIT;
+	git_str buf = GIT_STR_INIT;
 
-	if ((error = git_buf_puts(&buf, entry_path)) < 0)
+	if ((error = git_str_puts(&buf, entry_path)) < 0)
 		goto cleanup;
 
-	len = git_buf_len(&buf);
+	len = git_str_len(&buf);
 
 	while (i < len) {
 		if (buf.ptr[i] == '/') {
@@ -715,7 +706,7 @@ static int process_entry_path(
 	error = git_oid_fromstr(annotated_object_id, buf.ptr);
 
 cleanup:
-	git_buf_dispose(&buf);
+	git_str_dispose(&buf);
 	return error;
 }
 
@@ -780,7 +771,7 @@ int git_note_iterator_new(
 {
 	int error;
 	git_commit *commit = NULL;
-	git_buf notes_ref = GIT_BUF_INIT;
+	git_str notes_ref = GIT_STR_INIT;
 
 	error = retrieve_note_commit(&commit, &notes_ref, repo, notes_ref_in);
 	if (error < 0)
@@ -789,7 +780,7 @@ int git_note_iterator_new(
 	error = git_note_commit_iterator_new(it, commit);
 
 cleanup:
-	git_buf_dispose(&notes_ref);
+	git_str_dispose(&notes_ref);
 	git_commit_free(commit);
 
 	return error;