Continue implementation of git-diff

* Implemented git_diff_index_to_tree
* Reworked git_diff_options structure to handle more options
* Made most of the options in git_diff_options actually work
* Reorganized code a bit to remove some redundancy
* Added option parsing to examples/diff.c to test most options

5 files changed, 124 insertions, 27 deletions

diff --git a/tests-clar/diff/blob.c b/tests-clar/diff/blob.c
index 048b05c79..7aa8ceb22 100644
--- a/tests-clar/diff/blob.c
+++ b/tests-clar/diff/blob.c
@@ -22,7 +22,7 @@ void test_diff_blob__0(void)
 {
 	git_blob *a, *b, *c, *d;
 	git_oid a_oid, b_oid, c_oid, d_oid;
-	git_diff_options opts;
+	git_diff_options opts = {0};
 	diff_expects exp;
 
 	/* tests/resources/attr/root_test1 */
@@ -44,8 +44,7 @@ void test_diff_blob__0(void)
 	/* Doing the equivalent of a `git diff -U1` on these files */
 
 	opts.context_lines = 1;
-	opts.interhunk_lines = 0;
-	opts.ignore_whitespace = 0;
+	opts.interhunk_lines = 1;
 
 	memset(&exp, 0, sizeof(exp));
 	cl_git_pass(git_diff_blobs(
diff --git a/tests-clar/diff/diff_helpers.c b/tests-clar/diff/diff_helpers.c
index 3fcf45c10..b32c4bc2d 100644
--- a/tests-clar/diff/diff_helpers.c
+++ b/tests-clar/diff/diff_helpers.c
@@ -82,3 +82,23 @@ int diff_line_fn(
 	}
 	return 0;
 }
+
+git_tree *resolve_commit_oid_to_tree(
+	git_repository *repo,
+	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, 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;
+}
diff --git a/tests-clar/diff/diff_helpers.h b/tests-clar/diff/diff_helpers.h
index 4c3e7580e..035c000f5 100644
--- a/tests-clar/diff/diff_helpers.h
+++ b/tests-clar/diff/diff_helpers.h
@@ -38,3 +38,4 @@ extern int diff_line_fn(
 	char line_origin,
 	const char *content,
 	size_t content_len);
+
diff --git a/tests-clar/diff/index.c b/tests-clar/diff/index.c
new file mode 100644
index 000000000..0941c7c21
--- /dev/null
+++ b/tests-clar/diff/index.c
@@ -0,0 +1,96 @@
+#include "clar_libgit2.h"
+#include "diff_helpers.h"
+
+static git_repository *g_repo = NULL;
+
+void test_diff_index__initialize(void)
+{
+	cl_fixture_sandbox("status");
+	cl_git_pass(p_rename("status/.gitted", "status/.git"));
+	cl_git_pass(git_repository_open(&g_repo, "status/.git"));
+}
+
+void test_diff_index__cleanup(void)
+{
+	git_repository_free(g_repo);
+	g_repo = NULL;
+	cl_fixture_cleanup("status");
+}
+
+void test_diff_index__0(void)
+{
+	/* grabbed a couple of commit oids from the history of the attr repo */
+	const char *a_commit = "26a125ee1bf"; /* the current HEAD */
+	const char *b_commit = "0017bd4ab1ec3"; /* the start */
+	git_tree *a = resolve_commit_oid_to_tree(g_repo, a_commit);
+	git_tree *b = resolve_commit_oid_to_tree(g_repo, b_commit);
+	git_diff_options opts = {0};
+	git_diff_list *diff = NULL;
+	diff_expects exp;
+
+	cl_assert(a);
+	cl_assert(b);
+
+	opts.context_lines = 1;
+	opts.interhunk_lines = 1;
+
+	memset(&exp, 0, sizeof(exp));
+
+	cl_git_pass(git_diff_index_to_tree(g_repo, &opts, a, &diff));
+
+	cl_git_pass(git_diff_foreach(
+		diff, &exp, diff_file_fn, diff_hunk_fn, diff_line_fn));
+
+	/* to generate these values:
+	 * - cd to tests/resources/status,
+	 * - mv .gitted .git
+	 * - git diff --name-status --cached 26a125ee1bf
+	 * - git diff -U1 --cached 26a125ee1bf
+	 * - mv .git .gitted
+	 */
+	cl_assert(exp.files == 8);
+	cl_assert(exp.file_adds == 3);
+	cl_assert(exp.file_dels == 2);
+	cl_assert(exp.file_mods == 3);
+
+	cl_assert(exp.hunks == 8);
+
+	cl_assert(exp.lines == 11);
+	cl_assert(exp.line_ctxt == 3);
+	cl_assert(exp.line_adds == 6);
+	cl_assert(exp.line_dels == 2);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+	memset(&exp, 0, sizeof(exp));
+
+	cl_git_pass(git_diff_index_to_tree(g_repo, &opts, b, &diff));
+
+	cl_git_pass(git_diff_foreach(
+		diff, &exp, diff_file_fn, diff_hunk_fn, diff_line_fn));
+
+	/* to generate these values:
+	 * - cd to tests/resources/status,
+	 * - mv .gitted .git
+	 * - git diff --name-status --cached 0017bd4ab1ec3
+	 * - git diff -U1 --cached 0017bd4ab1ec3
+	 * - mv .git .gitted
+	 */
+	cl_assert(exp.files == 12);
+	cl_assert(exp.file_adds == 7);
+	cl_assert(exp.file_dels == 2);
+	cl_assert(exp.file_mods == 3);
+
+	cl_assert(exp.hunks == 12);
+
+	cl_assert(exp.lines == 16);
+	cl_assert(exp.line_ctxt == 3);
+	cl_assert(exp.line_adds == 11);
+	cl_assert(exp.line_dels == 2);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	git_tree_free(a);
+	git_tree_free(b);
+}
diff --git a/tests-clar/diff/tree.c b/tests-clar/diff/tree.c
index 3c5d2a9f2..836db5765 100644
--- a/tests-clar/diff/tree.c
+++ b/tests-clar/diff/tree.c
@@ -18,34 +18,16 @@ void test_diff_tree__cleanup(void)
 	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_tree *a = resolve_commit_oid_to_tree(g_repo, a_commit);
+	git_tree *b = resolve_commit_oid_to_tree(g_repo, b_commit);
+	git_tree *c = resolve_commit_oid_to_tree(g_repo, c_commit);
+	git_diff_options opts = {0};
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 
@@ -53,8 +35,7 @@ void test_diff_tree__0(void)
 	cl_assert(b);
 
 	opts.context_lines = 1;
-	opts.interhunk_lines = 0;
-	opts.ignore_whitespace = 0;
+	opts.interhunk_lines = 1;
 
 	memset(&exp, 0, sizeof(exp));