Introduce a function to create a tree based on a different onecmn/tree-update

Instead of going through the usual steps of reading a tree recursively
into an index, modifying it and writing it back out as a tree, introduce
a function to perform simple updates more efficiently.

`git_tree_create_updated` avoids reading trees which are not modified
and supports upsert and delete operations. It is not as versatile as
modifying the index, but it makes some common operations much more
efficient.

1 files changed, 167 insertions, 0 deletions

diff --git a/tests/object/tree/update.c b/tests/object/tree/update.c
new file mode 100644
index 000000000..210a50474
--- /dev/null
+++ b/tests/object/tree/update.c
@@ -0,0 +1,167 @@
+#include "clar_libgit2.h"
+#include "tree.h"
+
+static git_repository *g_repo;
+
+void test_object_tree_update__initialize(void)
+{
+	g_repo = cl_git_sandbox_init("testrepo");
+}
+
+void test_object_tree_update__cleanup(void)
+{
+   cl_git_sandbox_cleanup();
+}
+
+void test_object_tree_update__remove_blob(void)
+{
+	git_oid tree_index_id, tree_updater_id, base_id;
+	git_tree *base_tree;
+	git_index *idx;
+	const char *path = "README";
+
+	git_tree_update updates[] = {
+		{ GIT_TREE_UPDATE_REMOVE, {{0}}, GIT_FILEMODE_BLOB /* ignored */, path},
+	};
+
+	cl_git_pass(git_oid_fromstr(&base_id, "45dd856fdd4d89b884c340ba0e047752d9b085d6"));
+	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
+
+	/* Create it with an index */
+	cl_git_pass(git_index_new(&idx));
+	cl_git_pass(git_index_read_tree(idx, base_tree));
+	cl_git_pass(git_index_remove(idx, path, 0));
+	cl_git_pass(git_index_write_tree_to(&tree_index_id, idx, g_repo));
+	git_index_free(idx);
+
+	/* Perform the same operation via the tree updater */
+	cl_git_pass(git_tree_create_updated(&tree_updater_id, g_repo, base_tree, 1, updates));
+
+	cl_assert_equal_oid(&tree_index_id, &tree_updater_id);
+
+	git_tree_free(base_tree);
+}
+
+void test_object_tree_update__replace_blob(void)
+{
+	git_oid tree_index_id, tree_updater_id, base_id;
+	git_tree *base_tree;
+	git_index *idx;
+	const char *path = "README";
+	git_index_entry entry = { {0} };
+
+	git_tree_update updates[] = {
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, path},
+	};
+
+	cl_git_pass(git_oid_fromstr(&base_id, "45dd856fdd4d89b884c340ba0e047752d9b085d6"));
+	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
+
+	/* Create it with an index */
+	cl_git_pass(git_index_new(&idx));
+	cl_git_pass(git_index_read_tree(idx, base_tree));
+
+	entry.path = path;
+	cl_git_pass(git_oid_fromstr(&entry.id, "3697d64be941a53d4ae8f6a271e4e3fa56b022cc"));
+	entry.mode = GIT_FILEMODE_BLOB;
+	cl_git_pass(git_index_add(idx, &entry));
+
+	cl_git_pass(git_index_write_tree_to(&tree_index_id, idx, g_repo));
+	git_index_free(idx);
+
+	/* Perform the same operation via the tree updater */
+	cl_git_pass(git_oid_fromstr(&updates[0].id, "3697d64be941a53d4ae8f6a271e4e3fa56b022cc"));
+	cl_git_pass(git_tree_create_updated(&tree_updater_id, g_repo, base_tree, 1, updates));
+
+	cl_assert_equal_oid(&tree_index_id, &tree_updater_id);
+
+	git_tree_free(base_tree);
+}
+
+void test_object_tree_update__add_blobs(void)
+{
+	git_oid tree_index_id, tree_updater_id, base_id;
+	git_tree *base_tree;
+	git_index *idx;
+	git_index_entry entry = { {0} };
+	int i;
+	const char *paths[] = {
+		"some/deep/path",
+		"some/other/path",
+		"a/path/elsewhere",
+	};
+
+	git_tree_update updates[] = {
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[0]},
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[1]},
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[2]},
+	};
+
+	cl_git_pass(git_oid_fromstr(&base_id, "45dd856fdd4d89b884c340ba0e047752d9b085d6"));
+	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
+
+	entry.mode = GIT_FILEMODE_BLOB;
+	cl_git_pass(git_oid_fromstr(&entry.id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));
+
+	for (i = 0; i < 3; i++) {
+		cl_git_pass(git_oid_fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));
+	}
+
+	for (i = 0; i < 2; i++) {
+		int j;
+
+		/* Create it with an index */
+		cl_git_pass(git_index_new(&idx));
+
+		base_tree = NULL;
+		if (i == 1) {
+			cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
+			cl_git_pass(git_index_read_tree(idx, base_tree));
+		}
+
+		for (j = 0; j < 3; j++) {
+			entry.path = paths[j];
+			cl_git_pass(git_index_add(idx, &entry));
+		}
+
+		cl_git_pass(git_index_write_tree_to(&tree_index_id, idx, g_repo));
+		git_index_free(idx);
+
+		/* Perform the same operations via the tree updater */
+		cl_git_pass(git_tree_create_updated(&tree_updater_id, g_repo, base_tree, 3, updates));
+
+		cl_assert_equal_oid(&tree_index_id, &tree_updater_id);
+	}
+}
+
+void test_object_tree_update__add_conflict(void)
+{
+	int i;
+	git_oid tree_updater_id;
+	git_tree_update updates[] = {
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, "a/dir/blob"},
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, "a/dir"},
+	};
+
+	for (i = 0; i < 2; i++) {
+		cl_git_pass(git_oid_fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));
+	}
+
+	cl_git_fail(git_tree_create_updated(&tree_updater_id, g_repo, NULL, 2, updates));
+}
+
+void test_object_tree_update__add_conflict2(void)
+{
+	int i;
+	git_oid tree_updater_id;
+	git_tree_update updates[] = {
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, "a/dir/blob"},
+		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_TREE, "a/dir/blob"},
+	};
+
+	for (i = 0; i < 2; i++) {
+		cl_git_pass(git_oid_fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));
+	}
+
+	cl_git_fail(git_tree_create_updated(&tree_updater_id, g_repo, NULL, 2, updates));
+}