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, 9 insertions, 9 deletions

diff --git a/src/config_mem.c b/src/config_mem.c
index 5b573a995..560229cf5 100644
--- a/src/config_mem.c
+++ b/src/config_mem.c
@@ -14,7 +14,7 @@
 typedef struct {
 	git_config_backend parent;
 	git_config_entries *entries;
-	git_buf cfg;
+	git_str cfg;
 } config_memory_backend;
 
 typedef struct {
@@ -38,7 +38,7 @@ static int read_variable_cb(
 	void *payload)
 {
 	config_memory_parse_data *parse_data = (config_memory_parse_data *) payload;
-	git_buf buf = GIT_BUF_INIT;
+	git_str buf = GIT_STR_INIT;
 	git_config_entry *entry;
 	const char *c;
 	int result;
@@ -52,19 +52,19 @@ static int read_variable_cb(
 		 * here. Git appears to warn in most cases if it sees
 		 * un-namespaced config options.
 		 */
-		git_buf_puts(&buf, current_section);
-		git_buf_putc(&buf, '.');
+		git_str_puts(&buf, current_section);
+		git_str_putc(&buf, '.');
 	}
 
 	for (c = var_name; *c; c++)
-		git_buf_putc(&buf, git__tolower(*c));
+		git_str_putc(&buf, git__tolower(*c));
 
-	if (git_buf_oom(&buf))
+	if (git_str_oom(&buf))
 		return -1;
 
 	entry = git__calloc(1, sizeof(git_config_entry));
 	GIT_ERROR_CHECK_ALLOC(entry);
-	entry->name = git_buf_detach(&buf);
+	entry->name = git_str_detach(&buf);
 	entry->value = var_value ? git__strdup(var_value) : NULL;
 	entry->level = parse_data->level;
 	entry->include_depth = 0;
@@ -178,7 +178,7 @@ static void config_memory_free(git_config_backend *_backend)
 		return;
 
 	git_config_entries_free(backend->entries);
-	git_buf_dispose(&backend->cfg);
+	git_str_dispose(&backend->cfg);
 	git__free(backend);
 }
 
@@ -194,7 +194,7 @@ int git_config_backend_from_string(git_config_backend **out, const char *cfg, si
 		return -1;
 	}
 
-	if (git_buf_set(&backend->cfg, cfg, len) < 0) {
+	if (git_str_set(&backend->cfg, cfg, len) < 0) {
 		git_config_entries_free(backend->entries);
 		git__free(backend);
 		return -1;