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, 14 insertions, 15 deletions

diff --git a/tests/diff/workdir.c b/tests/diff/workdir.c
index 00c52ff1b..f7c74a294 100644
--- a/tests/diff/workdir.c
+++ b/tests/diff/workdir.c
@@ -1663,7 +1663,7 @@ void test_diff_workdir__patience_diff(void)
 	cl_git_pass(git_patch_to_buf(&buf, patch));
 
 	cl_assert_equal_s(expected_normal, buf.ptr);
-	git_buf_clear(&buf);
+	git_buf_dispose(&buf);
 	git_patch_free(patch);
 	git_diff_free(diff);
 
@@ -1675,9 +1675,8 @@ void test_diff_workdir__patience_diff(void)
 	cl_git_pass(git_patch_to_buf(&buf, patch));
 
 	cl_assert_equal_s(expected_patience, buf.ptr);
-	git_buf_clear(&buf);
-
 	git_buf_dispose(&buf);
+
 	git_patch_free(patch);
 	git_diff_free(diff);
 }
@@ -1754,7 +1753,7 @@ void test_diff_workdir__with_stale_index(void)
 	git_index_free(idx);
 }
 
-static int touch_file(void *payload, git_buf *path)
+static int touch_file(void *payload, git_str *path)
 {
 	struct stat st;
 	struct p_timeval times[2];
@@ -1804,10 +1803,10 @@ void test_diff_workdir__can_update_index(void)
 
 	/* touch all the files so stat times are different */
 	{
-		git_buf path = GIT_BUF_INIT;
-		cl_git_pass(git_buf_sets(&path, "status"));
+		git_str path = GIT_STR_INIT;
+		cl_git_pass(git_str_sets(&path, "status"));
 		cl_git_pass(git_path_direach(&path, 0, touch_file, NULL));
-		git_buf_dispose(&path);
+		git_str_dispose(&path);
 	}
 
 	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
@@ -1873,9 +1872,9 @@ void test_diff_workdir__binary_detection(void)
 {
 	git_index *idx;
 	git_diff *diff = NULL;
-	git_buf b = GIT_BUF_INIT;
+	git_str b = GIT_STR_INIT;
 	int i;
-	git_buf data[10] = {
+	git_str data[10] = {
 		{ "1234567890", 0, 10 },         /* 0 - all ascii text control */
 		{ "\xC3\x85\xC3\xBC\xE2\x80\xA0\x48\xC3\xB8\xCF\x80\xCE\xA9", 0, 14 },            /* 1 - UTF-8 multibyte text */
 		{ "\xEF\xBB\xBF\xC3\x9C\xE2\xA4\x92\xC6\x92\x38\xC2\xA3\xE2\x82\xAC", 0, 16 }, /* 2 - UTF-8 with BOM */
@@ -1899,7 +1898,7 @@ void test_diff_workdir__binary_detection(void)
 	 * then we will try with test data in index and ASCII in workdir.
 	 */
 
-	cl_git_pass(git_buf_sets(&b, "empty_standard_repo/0"));
+	cl_git_pass(git_str_sets(&b, "empty_standard_repo/0"));
 	for (i = 0; i < 10; ++i) {
 		b.ptr[b.size - 1] = '0' + i;
 		cl_git_mkfile(b.ptr, "baseline");
@@ -1931,7 +1930,7 @@ void test_diff_workdir__binary_detection(void)
 
 	git_diff_free(diff);
 
-	cl_git_pass(git_buf_sets(&b, "empty_standard_repo/0"));
+	cl_git_pass(git_str_sets(&b, "empty_standard_repo/0"));
 	for (i = 0; i < 10; ++i) {
 		b.ptr[b.size - 1] = '0' + i;
 		cl_git_pass(git_index_add_bypath(idx, &b.ptr[b.size - 1]));
@@ -1959,7 +1958,7 @@ void test_diff_workdir__binary_detection(void)
 	git_diff_free(diff);
 
 	git_index_free(idx);
-	git_buf_dispose(&b);
+	git_str_dispose(&b);
 }
 
 void test_diff_workdir__to_index_conflicted(void) {
@@ -2006,7 +2005,7 @@ void test_diff_workdir__only_writes_index_when_necessary(void)
 	git_reference *head;
 	git_object *head_object;
 	git_oid initial, first, second;
-	git_buf path = GIT_BUF_INIT;
+	git_str path = GIT_STR_INIT;
 	struct stat st;
 	struct p_timeval times[2];
 
@@ -2040,7 +2039,7 @@ void test_diff_workdir__only_writes_index_when_necessary(void)
 	cl_assert(!git_oid_equal(&initial, &first));
 
 	/* touch all the files so stat times are different */
-	cl_git_pass(git_buf_sets(&path, "status"));
+	cl_git_pass(git_str_sets(&path, "status"));
 	cl_git_pass(git_path_direach(&path, 0, touch_file, NULL));
 
 	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, NULL, &opts));
@@ -2050,7 +2049,7 @@ void test_diff_workdir__only_writes_index_when_necessary(void)
 	git_oid_cpy(&second, git_index_checksum(index));
 	cl_assert(!git_oid_equal(&first, &second));
 
-	git_buf_dispose(&path);
+	git_str_dispose(&path);
 	git_object_free(head_object);
 	git_reference_free(head);
 	git_index_free(index);