Use git_buf for path storage instead of stack-based buffers

This converts virtually all of the places that allocate GIT_PATH_MAX
buffers on the stack for manipulating paths to use git_buf objects
instead.  The patch is pretty careful not to touch the public API
for libgit2, so there are a few places that still use GIT_PATH_MAX.

This extends and changes some details of the git_buf implementation
to add a couple of extra functions and to make error handling easier.

This includes serious alterations to all the path.c functions, and
several of the fileops.c ones, too.  Also, there are a number of new
functions that parallel existing ones except that use a git_buf
instead of a stack-based buffer (such as git_config_find_global_r
that exists alongsize git_config_find_global).

This also modifies the win32 version of p_realpath to allocate whatever
buffer size is needed to accommodate the realpath instead of hardcoding
a GIT_PATH_MAX limit, but that change needs to be tested still.

2 files changed, 15 insertions, 12 deletions

diff --git a/tests-clay/repo/init.c b/tests-clay/repo/init.c
index 9677541ed..e235ffaeb 100644
--- a/tests-clay/repo/init.c
+++ b/tests-clay/repo/init.c
@@ -77,17 +77,19 @@ void test_repo_init__bare_repo_noslash(void)
 
 #if 0
 BEGIN_TEST(init2, "Initialize and open a bare repo with a relative path escaping out of the current working directory")
-	char path_repository[GIT_PATH_MAX];
+	git_buf path_repository = GIT_BUF_INIT;
 	char current_workdir[GIT_PATH_MAX];
 	const mode_t mode = 0777;
 	git_repository* repo;
 
 	must_pass(p_getcwd(current_workdir, sizeof(current_workdir)));
 
-	git_path_join(path_repository, TEMP_REPO_FOLDER, "a/b/c/");
-	must_pass(git_futils_mkdir_r(path_repository, mode));
+	must_pass(git_buf_joinpath(&path_repository, TEMP_REPO_FOLDER, "a/b/c/"));
+	must_pass(git_futils_mkdir_r(path_repository.ptr, mode));
 
-	must_pass(chdir(path_repository));
+	must_pass(chdir(path_repository.ptr));
+
+	git_buf_free(&path_repository);
 
 	must_pass(git_repository_init(&repo, "../d/e.git", 1));
 	must_pass(git__suffixcmp(git_repository_path(_repo), "/a/b/d/e.git/"));
diff --git a/tests-clay/repo/open.c b/tests-clay/repo/open.c
index 235af1447..05b01ceb2 100644
--- a/tests-clay/repo/open.c
+++ b/tests-clay/repo/open.c
@@ -26,23 +26,24 @@ void test_repo_open__standard_empty_repo(void)
 /* TODO TODO */
 #if 0
 BEGIN_TEST(open2, "Open a bare repository with a relative path escaping out of the current working directory")
-	char new_current_workdir[GIT_PATH_MAX];
 	char current_workdir[GIT_PATH_MAX];
-	char path_repository[GIT_PATH_MAX];
+	git_buf new_current_workdir = GIT_BUF_INIT;
+	git_buf path_repository = GIT_BUF_INIT;
 
 	const mode_t mode = 0777;
 	git_repository* repo;
 
 	/* Setup the repository to open */
 	must_pass(p_getcwd(current_workdir, sizeof(current_workdir)));
-	strcpy(path_repository, current_workdir);
-	git_path_join_n(path_repository, 3, path_repository, TEMP_REPO_FOLDER, "a/d/e.git");
-	must_pass(copydir_recurs(REPOSITORY_FOLDER, path_repository));
+	must_pass(git_buf_join_n(&path_repository, 3, current_workdir, TEMP_REPO_FOLDER, "a/d/e.git"));
+	must_pass(copydir_recurs(REPOSITORY_FOLDER, path_repository.ptr));
+	git_buf_free(&path_repository);
 
 	/* Change the current working directory */
-	git_path_join(new_current_workdir, TEMP_REPO_FOLDER, "a/b/c/");
-	must_pass(git_futils_mkdir_r(new_current_workdir, mode));
-	must_pass(chdir(new_current_workdir));
+	must_pass(git_buf_joinpath(&new_current_workdir, TEMP_REPO_FOLDER, "a/b/c/"));
+	must_pass(git_futils_mkdir_r(new_current_workdir.ptr, mode));
+	must_pass(chdir(new_current_workdir.ptr));
+	git_buf_free(&new_current_workdir);
 
 	must_pass(git_repository_open(&repo, "../../d/e.git"));