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, 10 insertions, 11 deletions

diff --git a/tests/refs/revparse.c b/tests/refs/revparse.c
index bc6e0a4c4..9c960702a 100644
--- a/tests/refs/revparse.c
+++ b/tests/refs/revparse.c
@@ -1,7 +1,6 @@
 #include "clar_libgit2.h"
 
 #include "git2/revparse.h"
-#include "buffer.h"
 #include "refs.h"
 #include "path.h"
 
@@ -292,7 +291,7 @@ void test_refs_revparse__upstream(void)
 void test_refs_revparse__ordinal(void)
 {
 	assert_invalid_single_spec("master@{-2}");
-	
+
 	/* TODO: make the test below actually fail
 	 * cl_git_fail(git_revparse_single(&g_obj, g_repo, "master@{1a}"));
 	 */
@@ -326,19 +325,19 @@ void test_refs_revparse__previous_head(void)
 static void create_fake_stash_reference_and_reflog(git_repository *repo)
 {
 	git_reference *master, *new_master;
-	git_buf log_path = GIT_BUF_INIT;
+	git_str log_path = GIT_STR_INIT;
 
-	git_buf_joinpath(&log_path, git_repository_path(repo), "logs/refs/fakestash");
+	git_str_joinpath(&log_path, git_repository_path(repo), "logs/refs/fakestash");
 
-	cl_assert_equal_i(false, git_path_isfile(git_buf_cstr(&log_path)));
+	cl_assert_equal_i(false, git_path_isfile(git_str_cstr(&log_path)));
 
 	cl_git_pass(git_reference_lookup(&master, repo, "refs/heads/master"));
 	cl_git_pass(git_reference_rename(&new_master, master, "refs/fakestash", 0, NULL));
 	git_reference_free(master);
 
-	cl_assert_equal_i(true, git_path_isfile(git_buf_cstr(&log_path)));
+	cl_assert_equal_i(true, git_path_isfile(git_str_cstr(&log_path)));
 
-	git_buf_dispose(&log_path);
+	git_str_dispose(&log_path);
 	git_reference_free(new_master);
 }
 
@@ -555,7 +554,7 @@ void test_refs_revparse__a_too_short_objectid_returns_EAMBIGUOUS(void)
 /*
  * $ echo "aabqhq" | git hash-object -t blob --stdin
  * dea509d0b3cb8ee0650f6ca210bc83f4678851ba
- * 
+ *
  * $ echo "aaazvc" | git hash-object -t blob --stdin
  * dea509d097ce692e167dfc6a48a7a280cc5e877e
  */
@@ -569,11 +568,11 @@ void test_refs_revparse__a_not_precise_enough_objectid_returns_EAMBIGUOUS(void)
 
 	cl_git_mkfile("testrepo/one.txt", "aabqhq\n");
 	cl_git_mkfile("testrepo/two.txt", "aaazvc\n");
-	
+
 	cl_git_pass(git_repository_index(&index, repo));
 	cl_git_pass(git_index_add_bypath(index, "one.txt"));
 	cl_git_pass(git_index_add_bypath(index, "two.txt"));
-	
+
 	cl_git_fail_with(git_revparse_single(&obj, repo, "dea509d0"), GIT_EAMBIGUOUS);
 
 	cl_git_pass(git_revparse_single(&obj, repo, "dea509d09"));
@@ -588,7 +587,7 @@ void test_refs_revparse__issue_994(void)
 	git_repository *repo;
 	git_reference *head, *with_at;
 	git_object *target;
-	
+
 	repo = cl_git_sandbox_init("testrepo.git");
 
 	cl_assert_equal_i(GIT_ENOTFOUND,