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, 34 insertions, 33 deletions

diff --git a/src/mailmap.c b/src/mailmap.c
index b69d55e2e..38ae01645 100644
--- a/src/mailmap.c
+++ b/src/mailmap.c
@@ -8,6 +8,7 @@
 #include "mailmap.h"
 
 #include "common.h"
+#include "config.h"
 #include "path.h"
 #include "repository.h"
 #include "signature.h"
@@ -90,21 +91,21 @@ static int advance_until(
 /*
  * Parse a single entry from a mailmap file.
  *
- * The output git_bufs will be non-owning, and should be copied before being
+ * The output git_strs will be non-owning, and should be copied before being
  * persisted.
  */
 static int parse_mailmap_entry(
-	git_buf *real_name, git_buf *real_email,
-	git_buf *replace_name, git_buf *replace_email,
+	git_str *real_name, git_str *real_email,
+	git_str *replace_name, git_str *replace_email,
 	git_parse_ctx *ctx)
 {
 	const char *start;
 	size_t len;
 
-	git_buf_clear(real_name);
-	git_buf_clear(real_email);
-	git_buf_clear(replace_name);
-	git_buf_clear(replace_email);
+	git_str_clear(real_name);
+	git_str_clear(real_email);
+	git_str_clear(replace_name);
+	git_str_clear(replace_email);
 
 	git_parse_advance_ws(ctx);
 	if (is_eol(ctx))
@@ -114,8 +115,8 @@ static int parse_mailmap_entry(
 	if (advance_until(&start, &len, ctx, '<') < 0)
 		return -1;
 
-	git_buf_attach_notowned(real_name, start, len);
-	git_buf_rtrim(real_name);
+	git_str_attach_notowned(real_name, start, len);
+	git_str_rtrim(real_name);
 
 	/*
 	 * If this is the last email in the line, this is the email to replace,
@@ -126,19 +127,19 @@ static int parse_mailmap_entry(
 
 	/* If we aren't at the end of the line, parse a second name and email */
 	if (!is_eol(ctx)) {
-		git_buf_attach_notowned(real_email, start, len);
+		git_str_attach_notowned(real_email, start, len);
 
 		git_parse_advance_ws(ctx);
 		if (advance_until(&start, &len, ctx, '<') < 0)
 			return -1;
-		git_buf_attach_notowned(replace_name, start, len);
-		git_buf_rtrim(replace_name);
+		git_str_attach_notowned(replace_name, start, len);
+		git_str_rtrim(replace_name);
 
 		if (advance_until(&start, &len, ctx, '>') < 0)
 			return -1;
 	}
 
-	git_buf_attach_notowned(replace_email, start, len);
+	git_str_attach_notowned(replace_email, start, len);
 
 	if (!is_eol(ctx))
 		return -1;
@@ -231,10 +232,10 @@ static int mailmap_add_buffer(git_mailmap *mm, const char *buf, size_t len)
 	git_parse_ctx ctx;
 
 	/* Scratch buffers containing the real parsed names & emails */
-	git_buf real_name = GIT_BUF_INIT;
-	git_buf real_email = GIT_BUF_INIT;
-	git_buf replace_name = GIT_BUF_INIT;
-	git_buf replace_email = GIT_BUF_INIT;
+	git_str real_name = GIT_STR_INIT;
+	git_str real_email = GIT_STR_INIT;
+	git_str replace_name = GIT_STR_INIT;
+	git_str replace_email = GIT_STR_INIT;
 
 	/* Buffers may not contain '\0's. */
 	if (memchr(buf, '\0', len) != NULL)
@@ -263,10 +264,10 @@ static int mailmap_add_buffer(git_mailmap *mm, const char *buf, size_t len)
 	}
 
 cleanup:
-	git_buf_dispose(&real_name);
-	git_buf_dispose(&real_email);
-	git_buf_dispose(&replace_name);
-	git_buf_dispose(&replace_email);
+	git_str_dispose(&real_name);
+	git_str_dispose(&real_email);
+	git_str_dispose(&replace_name);
+	git_str_dispose(&replace_email);
 	return error;
 }
 
@@ -289,7 +290,7 @@ static int mailmap_add_blob(
 {
 	git_object *object = NULL;
 	git_blob *blob = NULL;
-	git_buf content = GIT_BUF_INIT;
+	git_str content = GIT_STR_INIT;
 	int error;
 
 	GIT_ASSERT_ARG(mm);
@@ -312,7 +313,7 @@ static int mailmap_add_blob(
 		goto cleanup;
 
 cleanup:
-	git_buf_dispose(&content);
+	git_str_dispose(&content);
 	git_blob_free(blob);
 	git_object_free(object);
 	return error;
@@ -322,8 +323,8 @@ static int mailmap_add_file_ondisk(
 	git_mailmap *mm, const char *path, git_repository *repo)
 {
 	const char *base = repo ? git_repository_workdir(repo) : NULL;
-	git_buf fullpath = GIT_BUF_INIT;
-	git_buf content = GIT_BUF_INIT;
+	git_str fullpath = GIT_STR_INIT;
+	git_str content = GIT_STR_INIT;
 	int error;
 
 	error = git_path_join_unrooted(&fullpath, path, base, NULL);
@@ -343,8 +344,8 @@ static int mailmap_add_file_ondisk(
 		goto cleanup;
 
 cleanup:
-	git_buf_dispose(&fullpath);
-	git_buf_dispose(&content);
+	git_str_dispose(&fullpath);
+	git_str_dispose(&content);
 	return error;
 }
 
@@ -352,8 +353,8 @@ cleanup:
 static void mailmap_add_from_repository(git_mailmap *mm, git_repository *repo)
 {
 	git_config *config = NULL;
-	git_buf rev_buf = GIT_BUF_INIT;
-	git_buf path_buf = GIT_BUF_INIT;
+	git_str rev_buf = GIT_STR_INIT;
+	git_str path_buf = GIT_STR_INIT;
 	const char *rev = NULL;
 	const char *path = NULL;
 
@@ -363,9 +364,9 @@ static void mailmap_add_from_repository(git_mailmap *mm, git_repository *repo)
 
 	/* Try to load 'mailmap.file' and 'mailmap.blob' cfgs from the repo */
 	if (git_repository_config(&config, repo) == 0) {
-		if (git_config_get_string_buf(&rev_buf, config, MM_BLOB_CONFIG) == 0)
+		if (git_config__get_string_buf(&rev_buf, config, MM_BLOB_CONFIG) == 0)
 			rev = rev_buf.ptr;
-		if (git_config_get_path(&path_buf, config, MM_FILE_CONFIG) == 0)
+		if (git_config__get_path(&path_buf, config, MM_FILE_CONFIG) == 0)
 			path = path_buf.ptr;
 	}
 
@@ -387,8 +388,8 @@ static void mailmap_add_from_repository(git_mailmap *mm, git_repository *repo)
 	if (path != NULL)
 		mailmap_add_file_ondisk(mm, path, repo);
 
-	git_buf_dispose(&rev_buf);
-	git_buf_dispose(&path_buf);
+	git_str_dispose(&rev_buf);
+	git_str_dispose(&path_buf);
 	git_config_free(config);
 }