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, 27 insertions, 27 deletions

diff --git a/src/tree.c b/src/tree.c
index b1df79eac..c1e39158d 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -495,7 +495,7 @@ static int check_entry(git_repository *repo, const char *filename, const git_oid
 static int git_treebuilder__write_with_buffer(
 	git_oid *oid,
 	git_treebuilder *bld,
-	git_buf *buf)
+	git_str *buf)
 {
 	int error = 0;
 	size_t i, entrycount;
@@ -503,14 +503,14 @@ static int git_treebuilder__write_with_buffer(
 	git_tree_entry *entry;
 	git_vector entries = GIT_VECTOR_INIT;
 
-	git_buf_clear(buf);
+	git_str_clear(buf);
 
 	entrycount = git_strmap_size(bld->map);
 	if ((error = git_vector_init(&entries, entrycount, entry_sort_cmp)) < 0)
 		goto out;
 
 	if (buf->asize == 0 &&
-	    (error = git_buf_grow(buf, entrycount * 72)) < 0)
+	    (error = git_str_grow(buf, entrycount * 72)) < 0)
 		goto out;
 
 	git_strmap_foreach_value(bld->map, entry, {
@@ -523,11 +523,11 @@ static int git_treebuilder__write_with_buffer(
 	for (i = 0; i < entries.length && !error; ++i) {
 		entry = git_vector_get(&entries, i);
 
-		git_buf_printf(buf, "%o ", entry->attr);
-		git_buf_put(buf, entry->filename, entry->filename_len + 1);
-		git_buf_put(buf, (char *)entry->oid->id, GIT_OID_RAWSZ);
+		git_str_printf(buf, "%o ", entry->attr);
+		git_str_put(buf, entry->filename, entry->filename_len + 1);
+		git_str_put(buf, (char *)entry->oid->id, GIT_OID_RAWSZ);
 
-		if (git_buf_oom(buf)) {
+		if (git_str_oom(buf)) {
 			error = -1;
 			goto out;
 		}
@@ -575,7 +575,7 @@ static int write_tree(
 	git_index *index,
 	const char *dirname,
 	size_t start,
-	git_buf *shared_buf)
+	git_str *shared_buf)
 {
 	git_treebuilder *bld = NULL;
 	size_t i, entries = git_index_entrycount(index);
@@ -676,7 +676,7 @@ int git_tree__write_index(
 {
 	int ret;
 	git_tree *tree;
-	git_buf shared_buf = GIT_BUF_INIT;
+	git_str shared_buf = GIT_STR_INIT;
 	bool old_ignore_case = false;
 
 	GIT_ASSERT_ARG(oid);
@@ -705,7 +705,7 @@ int git_tree__write_index(
 	}
 
 	ret = write_tree(oid, repo, index, "", 0, &shared_buf);
-	git_buf_dispose(&shared_buf);
+	git_str_dispose(&shared_buf);
 
 	if (old_ignore_case)
 		git_index__set_ignore_case(index, true);
@@ -879,7 +879,7 @@ void git_treebuilder_free(git_treebuilder *bld)
 	if (bld == NULL)
 		return;
 
-	git_buf_dispose(&bld->write_cache);
+	git_str_dispose(&bld->write_cache);
 	git_treebuilder_clear(bld);
 	git_strmap_free(bld->map);
 	git__free(bld);
@@ -959,7 +959,7 @@ int git_tree_entry_bypath(
 static int tree_walk(
 	const git_tree *tree,
 	git_treewalk_cb callback,
-	git_buf *path,
+	git_str *path,
 	void *payload,
 	bool preorder)
 {
@@ -982,17 +982,17 @@ static int tree_walk(
 
 		if (git_tree_entry__is_tree(entry)) {
 			git_tree *subtree;
-			size_t path_len = git_buf_len(path);
+			size_t path_len = git_str_len(path);
 
 			error = git_tree_lookup(&subtree, tree->object.repo, entry->oid);
 			if (error < 0)
 				break;
 
 			/* append the next entry to the path */
-			git_buf_puts(path, entry->filename);
-			git_buf_putc(path, '/');
+			git_str_puts(path, entry->filename);
+			git_str_putc(path, '/');
 
-			if (git_buf_oom(path))
+			if (git_str_oom(path))
 				error = -1;
 			else
 				error = tree_walk(subtree, callback, path, payload, preorder);
@@ -1001,7 +1001,7 @@ static int tree_walk(
 			if (error != 0)
 				break;
 
-			git_buf_truncate(path, path_len);
+			git_str_truncate(path, path_len);
 		}
 
 		if (!preorder) {
@@ -1024,7 +1024,7 @@ int git_tree_walk(
 	void *payload)
 {
 	int error = 0;
-	git_buf root_path = GIT_BUF_INIT;
+	git_str root_path = GIT_STR_INIT;
 
 	if (mode != GIT_TREEWALK_POST && mode != GIT_TREEWALK_PRE) {
 		git_error_set(GIT_ERROR_INVALID, "invalid walking mode for tree walk");
@@ -1034,7 +1034,7 @@ int git_tree_walk(
 	error = tree_walk(
 		tree, callback, &root_path, payload, (mode == GIT_TREEWALK_PRE));
 
-	git_buf_dispose(&root_path);
+	git_str_dispose(&root_path);
 
 	return error;
 }
@@ -1080,19 +1080,19 @@ GIT_INLINE(size_t) count_slashes(const char *path)
 	return count;
 }
 
-static bool next_component(git_buf *out, const char *in)
+static bool next_component(git_str *out, const char *in)
 {
 	const char *slash = strchr(in, '/');
 
-	git_buf_clear(out);
+	git_str_clear(out);
 
 	if (slash)
-		git_buf_put(out, in, slash - in);
+		git_str_put(out, in, slash - in);
 
 	return !!slash;
 }
 
-static int create_popped_tree(tree_stack_entry *current, tree_stack_entry *popped, git_buf *component)
+static int create_popped_tree(tree_stack_entry *current, tree_stack_entry *popped, git_str *component)
 {
 	int error;
 	git_oid new_tree;
@@ -1116,8 +1116,8 @@ static int create_popped_tree(tree_stack_entry *current, tree_stack_entry *poppe
 	}
 
 	/* We've written out the tree, now we have to put the new value into its parent */
-	git_buf_clear(component);
-	git_buf_puts(component, popped->name);
+	git_str_clear(component);
+	git_str_puts(component, popped->name);
 	git__free(popped->name);
 
 	GIT_ERROR_CHECK_ALLOC(component->ptr);
@@ -1142,7 +1142,7 @@ int git_tree_create_updated(git_oid *out, git_repository *repo, git_tree *baseli
 	git_vector entries;
 	int error;
 	size_t i;
-	git_buf component = GIT_BUF_INIT;
+	git_str component = GIT_STR_INIT;
 
 	if ((error = git_vector_init(&entries, nupdates, compare_entries)) < 0)
 		return error;
@@ -1300,7 +1300,7 @@ cleanup:
 		}
 	}
 
-	git_buf_dispose(&component);
+	git_str_dispose(&component);
 	git_array_clear(stack);
 	git_vector_free(&entries);
 	return error;