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, 26 insertions, 26 deletions

diff --git a/src/diff_driver.c b/src/diff_driver.c
index a3892d35e..f6b51d8ba 100644
--- a/src/diff_driver.c
+++ b/src/diff_driver.c
@@ -90,7 +90,7 @@ static int diff_driver_add_patterns(
 	int error = 0;
 	const char *scan, *end;
 	git_diff_driver_pattern *pat = NULL;
-	git_buf buf = GIT_BUF_INIT;
+	git_str buf = GIT_STR_INIT;
 
 	for (scan = regex_str; scan; scan = end) {
 		/* get pattern to fill in */
@@ -105,10 +105,10 @@ static int diff_driver_add_patterns(
 		}
 
 		if ((end = strchr(scan, '\n')) != NULL) {
-			error = git_buf_set(&buf, scan, end - scan);
+			error = git_str_set(&buf, scan, end - scan);
 			end++;
 		} else {
-			error = git_buf_sets(&buf, scan);
+			error = git_str_sets(&buf, scan);
 		}
 		if (error < 0)
 			break;
@@ -122,7 +122,7 @@ static int diff_driver_add_patterns(
 
 	if (error && pat != NULL)
 		(void)git_array_pop(drv->fn_patterns); /* release last item */
-	git_buf_dispose(&buf);
+	git_str_dispose(&buf);
 
 	/* We want to ignore bad patterns, so return success regardless */
 	return 0;
@@ -237,7 +237,7 @@ static int git_diff_driver_load(
 	git_diff_driver *drv;
 	size_t namelen;
 	git_config *cfg = NULL;
-	git_buf name = GIT_BUF_INIT;
+	git_str name = GIT_STR_INIT;
 	git_config_entry *ce = NULL;
 	bool found_driver = false;
 
@@ -260,7 +260,7 @@ static int git_diff_driver_load(
 		goto done;
 	}
 
-	if ((error = git_buf_printf(&name, "diff.%s.binary", driver_name)) < 0)
+	if ((error = git_str_printf(&name, "diff.%s.binary", driver_name)) < 0)
 		goto done;
 
 	switch (git_config__get_bool_force(cfg, name.ptr, -1)) {
@@ -281,8 +281,8 @@ static int git_diff_driver_load(
 
 	/* TODO: warn if diff.<name>.command or diff.<name>.textconv are set */
 
-	git_buf_truncate(&name, namelen + strlen("diff.."));
-	if ((error = git_buf_PUTS(&name, "xfuncname")) < 0)
+	git_str_truncate(&name, namelen + strlen("diff.."));
+	if ((error = git_str_PUTS(&name, "xfuncname")) < 0)
 		goto done;
 
 	if ((error = git_config_get_multivar_foreach(
@@ -292,8 +292,8 @@ static int git_diff_driver_load(
 		git_error_clear(); /* no diff.<driver>.xfuncname, so just continue */
 	}
 
-	git_buf_truncate(&name, namelen + strlen("diff.."));
-	if ((error = git_buf_PUTS(&name, "funcname")) < 0)
+	git_str_truncate(&name, namelen + strlen("diff.."));
+	if ((error = git_str_PUTS(&name, "funcname")) < 0)
 		goto done;
 
 	if ((error = git_config_get_multivar_foreach(
@@ -309,8 +309,8 @@ static int git_diff_driver_load(
 		found_driver = true;
 	}
 
-	git_buf_truncate(&name, namelen + strlen("diff.."));
-	if ((error = git_buf_PUTS(&name, "wordregex")) < 0)
+	git_str_truncate(&name, namelen + strlen("diff.."));
+	if ((error = git_str_PUTS(&name, "wordregex")) < 0)
 		goto done;
 
 	if ((error = git_config__lookup_entry(&ce, cfg, name.ptr, false)) < 0)
@@ -340,7 +340,7 @@ static int git_diff_driver_load(
 
 done:
 	git_config_entry_free(ce);
-	git_buf_dispose(&name);
+	git_str_dispose(&name);
 	git_config_free(cfg);
 
 	if (!*out) {
@@ -420,11 +420,11 @@ void git_diff_driver_update_options(
 int git_diff_driver_content_is_binary(
 	git_diff_driver *driver, const char *content, size_t content_len)
 {
-	git_buf search = GIT_BUF_INIT;
+	git_str search = GIT_STR_INIT;
 
 	GIT_UNUSED(driver);
 
-	git_buf_attach_notowned(&search, content,
+	git_str_attach_notowned(&search, content,
 		min(content_len, GIT_FILTER_BYTES_TO_CHECK_NUL));
 
 	/* TODO: provide encoding / binary detection callbacks that can
@@ -432,15 +432,15 @@ int git_diff_driver_content_is_binary(
 	 * let's just use the simple NUL-byte detection that core git uses.
 	 */
 
-	/* previously was: if (git_buf_is_binary(&search)) */
-	if (git_buf_contains_nul(&search))
+	/* previously was: if (git_str_is_binary(&search)) */
+	if (git_str_contains_nul(&search))
 		return 1;
 
 	return 0;
 }
 
 static int diff_context_line__simple(
-	git_diff_driver *driver, git_buf *line)
+	git_diff_driver *driver, git_str *line)
 {
 	char firstch = line->ptr[0];
 	GIT_UNUSED(driver);
@@ -448,7 +448,7 @@ static int diff_context_line__simple(
 }
 
 static int diff_context_line__pattern_match(
-	git_diff_driver *driver, git_buf *line)
+	git_diff_driver *driver, git_str *line)
 {
 	size_t i, maxi = git_array_size(driver->fn_patterns);
 	git_regmatch pmatch[2];
@@ -462,9 +462,9 @@ static int diff_context_line__pattern_match(
 
 			/* use pmatch data to trim line data */
 			i = (pmatch[1].start >= 0) ? 1 : 0;
-			git_buf_consume(line, git_buf_cstr(line) + pmatch[i].start);
-			git_buf_truncate(line, pmatch[i].end - pmatch[i].start);
-			git_buf_rtrim(line);
+			git_str_consume(line, git_str_cstr(line) + pmatch[i].start);
+			git_str_truncate(line, pmatch[i].end - pmatch[i].start);
+			git_str_rtrim(line);
 
 			return true;
 		}
@@ -482,9 +482,9 @@ static long diff_context_find(
 {
 	git_diff_find_context_payload *ctxt = payload;
 
-	if (git_buf_set(&ctxt->line, line, (size_t)line_len) < 0)
+	if (git_str_set(&ctxt->line, line, (size_t)line_len) < 0)
 		return -1;
-	git_buf_rtrim(&ctxt->line);
+	git_str_rtrim(&ctxt->line);
 
 	if (!ctxt->line.size)
 		return -1;
@@ -511,14 +511,14 @@ void git_diff_find_context_init(
 		payload_out->driver = driver;
 		payload_out->match_line = (driver->type == DIFF_DRIVER_PATTERNLIST) ?
 			diff_context_line__pattern_match : diff_context_line__simple;
-		git_buf_init(&payload_out->line, 0);
+		git_str_init(&payload_out->line, 0);
 	}
 }
 
 void git_diff_find_context_clear(git_diff_find_context_payload *payload)
 {
 	if (payload) {
-		git_buf_dispose(&payload->line);
+		git_str_dispose(&payload->line);
 		payload->driver = NULL;
 	}
 }