Clean up diff implementation for review

This fixes several bugs, updates tests and docs, eliminates the
FILE* assumption in favor of printing callbacks for the diff patch
formatter helpers, and adds a "diff" example function that can
perform a diff from the command line.

1 files changed, 105 insertions, 0 deletions

diff --git a/tests-clar/diff/tree.c b/tests-clar/diff/tree.c
new file mode 100644
index 000000000..3c5d2a9f2
--- /dev/null
+++ b/tests-clar/diff/tree.c
@@ -0,0 +1,105 @@
+#include "clar_libgit2.h"
+#include "diff_helpers.h"
+
+static git_repository *g_repo = NULL;
+
+void test_diff_tree__initialize(void)
+{
+	cl_fixture_sandbox("attr");
+	cl_git_pass(p_rename("attr/.gitted", "attr/.git"));
+	cl_git_pass(p_rename("attr/gitattributes", "attr/.gitattributes"));
+	cl_git_pass(git_repository_open(&g_repo, "attr/.git"));
+}
+
+void test_diff_tree__cleanup(void)
+{
+	git_repository_free(g_repo);
+	g_repo = NULL;
+	cl_fixture_cleanup("attr");
+}
+
+static git_tree *resolve_commit_oid_to_tree(const char *partial_oid)
+{
+	size_t len = strlen(partial_oid);
+	git_oid oid;
+	git_object *obj;
+	git_tree *tree;
+
+	if (git_oid_fromstrn(&oid, partial_oid, len) == 0)
+		git_object_lookup_prefix(&obj, g_repo, &oid, len, GIT_OBJ_ANY);
+	cl_assert(obj);
+	if (git_object_type(obj) == GIT_OBJ_TREE)
+		return (git_tree *)obj;
+	cl_assert(git_object_type(obj) == GIT_OBJ_COMMIT);
+	cl_git_pass(git_commit_tree(&tree, (git_commit *)obj));
+	git_object_free(obj);
+	return tree;
+}
+
+void test_diff_tree__0(void)
+{
+	/* grabbed a couple of commit oids from the history of the attr repo */
+	const char *a_commit = "605812a";
+	const char *b_commit = "370fe9ec22";
+	const char *c_commit = "f5b0af1fb4f5c";
+	git_tree *a = resolve_commit_oid_to_tree(a_commit);
+	git_tree *b = resolve_commit_oid_to_tree(b_commit);
+	git_tree *c = resolve_commit_oid_to_tree(c_commit);
+	git_diff_options opts;
+	git_diff_list *diff = NULL;
+	diff_expects exp;
+
+	cl_assert(a);
+	cl_assert(b);
+
+	opts.context_lines = 1;
+	opts.interhunk_lines = 0;
+	opts.ignore_whitespace = 0;
+
+	memset(&exp, 0, sizeof(exp));
+
+	cl_git_pass(git_diff_tree_to_tree(g_repo, &opts, a, b, &diff));
+
+	cl_git_pass(git_diff_foreach(
+		diff, &exp, diff_file_fn, diff_hunk_fn, diff_line_fn));
+
+	cl_assert(exp.files == 5);
+	cl_assert(exp.file_adds == 2);
+	cl_assert(exp.file_dels == 1);
+	cl_assert(exp.file_mods == 2);
+
+	cl_assert(exp.hunks == 5);
+
+	cl_assert(exp.lines == 7 + 24 + 1 + 6 + 6);
+	cl_assert(exp.line_ctxt == 1);
+	cl_assert(exp.line_adds == 24 + 1 + 5 + 5);
+	cl_assert(exp.line_dels == 7 + 1);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	memset(&exp, 0, sizeof(exp));
+
+	cl_git_pass(git_diff_tree_to_tree(g_repo, &opts, c, b, &diff));
+
+	cl_git_pass(git_diff_foreach(
+		diff, &exp, diff_file_fn, diff_hunk_fn, diff_line_fn));
+
+	cl_assert(exp.files == 2);
+	cl_assert(exp.file_adds == 0);
+	cl_assert(exp.file_dels == 0);
+	cl_assert(exp.file_mods == 2);
+
+	cl_assert(exp.hunks == 2);
+
+	cl_assert(exp.lines == 8 + 15);
+	cl_assert(exp.line_ctxt == 1);
+	cl_assert(exp.line_adds == 1);
+	cl_assert(exp.line_dels == 7 + 14);
+
+	git_diff_list_free(diff);
+
+	git_tree_free(a);
+	git_tree_free(b);
+	git_tree_free(c);
+}