stash: add git_stash_save()

1 files changed, 577 insertions, 0 deletions

diff --git a/src/stash.c b/src/stash.c
new file mode 100644
index 000000000..e63ee99e3
--- /dev/null
+++ b/src/stash.c
@@ -0,0 +1,577 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "common.h"
+#include "repository.h"
+#include "commit.h"
+#include "tree.h"
+#include "reflog.h"
+#include "git2/diff.h"
+#include "git2/stash.h"
+#include "git2/status.h"
+#include "git2/checkout.h"
+
+static int create_error(int error, const char *msg)
+{
+	giterr_set(GITERR_STASH, "Cannot stash changes - %s", msg);
+	return error;
+}
+
+static int ensure_non_bare_repository(git_repository *repo)
+{
+	if (!git_repository_is_bare(repo))
+		return 0;
+
+	return create_error(GIT_EBAREREPO,
+		"Stash related operations require a working directory.");
+}
+
+static int retrieve_head(git_reference **out, git_repository *repo)
+{
+	int error = git_repository_head(out, repo);
+
+	if (error == GIT_EORPHANEDHEAD)
+		return create_error(error, "You do not have the initial commit yet.");
+
+	return error;
+}
+
+static int append_abbreviated_oid(git_buf *out, const git_oid *b_commit)
+{
+	char *formatted_oid;
+
+	formatted_oid = git_oid_allocfmt(b_commit);
+	GITERR_CHECK_ALLOC(formatted_oid);
+
+	git_buf_put(out, formatted_oid, 7);
+	git__free(formatted_oid);
+
+	return git_buf_oom(out) ? -1 : 0;
+}
+
+static int append_commit_description(git_buf *out, git_commit* commit)
+{
+	const char *message;
+	int pos = 0, len;
+
+	if (append_abbreviated_oid(out, git_commit_id(commit)) < 0)
+		return -1;
+
+	message = git_commit_message(commit);
+	len = strlen(message);
+
+	/* TODO: Replace with proper commit short message
+	 * when git_commit_message_short() is implemented.
+	 */
+	while (pos < len && message[pos] != '\n')
+		pos++;
+
+	git_buf_putc(out, ' ');
+	git_buf_put(out, message, pos);
+	git_buf_putc(out, '\n');
+
+	return git_buf_oom(out) ? -1 : 0;
+}
+
+static int retrieve_base_commit_and_message(
+	git_commit **b_commit,
+	git_buf *stash_message,
+	git_repository *repo)
+{
+	git_reference *head = NULL;
+	int error;
+
+	if ((error = retrieve_head(&head, repo)) < 0)
+		return error;
+
+	error = -1;
+
+	if (strcmp("HEAD", git_reference_name(head)) == 0)
+		git_buf_puts(stash_message, "(no branch): ");
+	else
+		git_buf_printf(
+			stash_message,
+			"%s: ",
+			git_reference_name(head) + strlen(GIT_REFS_HEADS_DIR));
+
+	if (git_commit_lookup(b_commit, repo, git_reference_oid(head)) < 0)
+		goto cleanup;
+
+	if (append_commit_description(stash_message, *b_commit) < 0)
+		goto cleanup;
+
+	error = 0;
+
+cleanup:
+	git_reference_free(head);
+	return error;
+}
+
+static int build_tree_from_index(git_tree **out, git_index *index)
+{
+	git_oid i_tree_oid;
+
+	if (git_tree_create_fromindex(&i_tree_oid, index) < 0)
+		return -1;
+
+	return git_tree_lookup(out, git_index_owner(index), &i_tree_oid);
+}
+
+static int commit_index(
+	git_commit **i_commit,
+	git_index *index,
+	git_signature *stasher,
+	const char *message,
+	const git_commit *parent)
+{
+	git_tree *i_tree = NULL;
+	git_oid i_commit_oid;
+	git_buf msg = GIT_BUF_INIT;
+	int error = -1;
+
+	if (build_tree_from_index(&i_tree, index) < 0)
+		goto cleanup;
+
+	if (git_buf_printf(&msg, "index on %s\n", message) < 0)
+		goto cleanup;
+
+	if (git_commit_create(
+		&i_commit_oid,
+		git_index_owner(index),
+		NULL,
+		stasher,
+		stasher,
+		NULL,
+		git_buf_cstr(&msg),
+		i_tree,
+		1,
+		&parent) < 0)
+			goto cleanup;
+
+	error = git_commit_lookup(i_commit, git_index_owner(index), &i_commit_oid);
+
+cleanup:
+	git_tree_free(i_tree);
+	git_buf_free(&msg);
+	return error;
+}
+
+struct cb_data {
+	git_index *index;
+
+	bool include_changed;
+	bool include_untracked;
+	bool include_ignored;
+};
+
+static int update_index_cb(
+	void *cb_data,
+	const git_diff_delta *delta,
+	float progress)
+{
+	int pos;
+	struct cb_data *data = (struct cb_data *)cb_data;
+
+	GIT_UNUSED(progress);
+
+	switch (delta->status) {
+	case GIT_DELTA_IGNORED:
+		if (!data->include_ignored)
+			break;
+
+		return git_index_add(data->index, delta->new_file.path, 0);
+
+	case GIT_DELTA_UNTRACKED:
+		if (!data->include_untracked)
+			break;
+
+		return git_index_add(data->index, delta->new_file.path, 0);
+
+	case GIT_DELTA_ADDED:
+		/* Fall through */
+	case GIT_DELTA_MODIFIED:
+		if (!data->include_changed)
+			break;
+
+		return git_index_add(data->index, delta->new_file.path, 0);
+
+	case GIT_DELTA_DELETED:
+		if (!data->include_changed)
+			break;
+
+		if ((pos = git_index_find(data->index, delta->new_file.path)) < 0)
+			return -1;
+
+		if (git_index_remove(data->index, pos) < 0)
+			return -1;
+
+	default:
+		/* Unimplemented */
+		giterr_set(
+			GITERR_INVALID,
+			"Cannot update index. Unimplemented status kind (%d)",
+			delta->status);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int build_untracked_tree(
+	git_tree **tree_out,
+	git_index *index,
+	git_commit *i_commit,
+	uint32_t flags)
+{
+	git_tree *i_tree = NULL;
+	git_diff_list *diff = NULL;
+	git_diff_options opts = {0};
+	struct cb_data data = {0};
+	int error = -1;
+
+	git_index_clear(index);
+
+	data.index = index;
+
+	if (flags & GIT_STASH_INCLUDE_UNTRACKED) {
+		opts.flags |= GIT_DIFF_INCLUDE_UNTRACKED | GIT_DIFF_RECURSE_UNTRACKED_DIRS;
+		data.include_untracked = true;
+	}
+
+	if (flags & GIT_STASH_INCLUDE_IGNORED) {
+		opts.flags |= GIT_DIFF_INCLUDE_IGNORED;
+		data.include_ignored = true;
+	}
+
+	if (git_commit_tree(&i_tree, i_commit) < 0)
+		goto cleanup;
+
+	if (git_diff_workdir_to_tree(git_index_owner(index), &opts, i_tree, &diff) < 0)
+		goto cleanup;
+
+	if (git_diff_foreach(diff, &data, update_index_cb, NULL, NULL) < 0)
+		goto cleanup;
+
+	if (build_tree_from_index(tree_out, index) < 0)
+		goto cleanup;
+
+	error = 0;
+
+cleanup:
+	git_diff_list_free(diff);
+	git_tree_free(i_tree);
+	return error;
+}
+
+static int commit_untracked(
+	git_commit **u_commit,
+	git_index *index,
+	git_signature *stasher,
+	const char *message,
+	git_commit *i_commit,
+	uint32_t flags)
+{
+	git_tree *u_tree = NULL;
+	git_oid u_commit_oid;
+	git_buf msg = GIT_BUF_INIT;
+	int error = -1;
+
+	if (build_untracked_tree(&u_tree, index, i_commit, flags) < 0)
+		goto cleanup;
+
+	if (git_buf_printf(&msg, "untracked files on %s\n", message) < 0)
+		goto cleanup;
+
+	if (git_commit_create(
+		&u_commit_oid,
+		git_index_owner(index),
+		NULL,
+		stasher,
+		stasher,
+		NULL,
+		git_buf_cstr(&msg),
+		u_tree,
+		0,
+		NULL) < 0)
+			goto cleanup;
+
+	error = git_commit_lookup(u_commit, git_index_owner(index), &u_commit_oid);
+
+cleanup:
+	git_tree_free(u_tree);
+	git_buf_free(&msg);
+	return error;
+}
+
+static int build_workdir_tree(
+	git_tree **tree_out,
+	git_index *index,
+	git_commit *b_commit)
+{
+	git_tree *b_tree = NULL;
+	git_diff_list *diff = NULL, *diff2 = NULL;
+	git_diff_options opts = {0};
+	struct cb_data data = {0};
+	int error = -1;
+
+	if (git_commit_tree(&b_tree, b_commit) < 0)
+		goto cleanup;
+
+	if (git_diff_index_to_tree(git_index_owner(index), &opts, b_tree, &diff) < 0)
+		goto cleanup;
+
+	if (git_diff_workdir_to_index(git_index_owner(index), &opts, &diff2) < 0)
+		goto cleanup;
+
+	if (git_diff_merge(diff, diff2) < 0)
+		goto cleanup;
+
+	data.index = index;
+	data.include_changed = true;
+
+	if (git_diff_foreach(diff, &data, update_index_cb, NULL, NULL) < 0)
+		goto cleanup;
+
+	if (build_tree_from_index(tree_out, index) < 0)
+		goto cleanup;
+
+	error = 0;
+
+cleanup:
+	git_diff_list_free(diff);
+	git_diff_list_free(diff2);
+	git_tree_free(b_tree);
+	return error;
+}
+
+static int commit_worktree(
+	git_oid *w_commit_oid,
+	git_index *index,
+	git_signature *stasher,
+	const char *message,
+	git_commit *i_commit,
+	git_commit *b_commit,
+	git_commit *u_commit)
+{
+	git_tree *w_tree = NULL, *i_tree = NULL;
+	int error = -1;
+
+	const git_commit *parents[] = {	NULL, NULL,	NULL };
+
+	parents[0] = b_commit;
+	parents[1] = i_commit;
+	parents[2] = u_commit;
+
+	if (git_commit_tree(&i_tree, i_commit) < 0)
+		return -1;
+
+	if (git_index_read_tree(index, i_tree) < 0)
+		goto cleanup;
+
+	if (build_workdir_tree(&w_tree, index, b_commit) < 0)
+		goto cleanup;
+
+	if (git_commit_create(
+		w_commit_oid,
+		git_index_owner(index),
+		NULL,
+		stasher,
+		stasher,
+		NULL,
+		message,
+		w_tree,
+		u_commit ? 3 : 2, parents) < 0)
+			goto cleanup;
+
+	error = 0;
+
+cleanup:
+	git_tree_free(i_tree);
+	git_tree_free(w_tree);
+	return error;
+}
+
+static int prepare_worktree_commit_message(
+	git_buf* msg,
+	const char *user_message)
+{
+	git_buf buf = GIT_BUF_INIT;
+	int error = -1;
+
+	git_buf_set(&buf, git_buf_cstr(msg), git_buf_len(msg));
+	git_buf_clear(msg);
+
+	if (!user_message)
+		git_buf_printf(msg, "WIP on %s", git_buf_cstr(&buf));
+	else {
+		const char *colon;
+
+		if ((colon = strchr(git_buf_cstr(&buf), ':')) == NULL)
+			goto cleanup;
+
+		git_buf_puts(msg, "On ");
+		git_buf_put(msg, git_buf_cstr(&buf), colon - buf.ptr);
+		git_buf_printf(msg, ": %s\n", user_message);
+	}
+
+	error = git_buf_oom(msg) || git_buf_oom(&buf) ? -1 : 0;
+
+cleanup:
+	git_buf_free(&buf);
+	return error;
+}
+
+static int update_reflog(
+	git_oid *w_commit_oid,
+	git_repository *repo,
+	git_signature *stasher,
+	const char *message)
+{
+	git_reference *stash = NULL;
+	git_reflog *reflog = NULL;
+	int error;
+
+	if ((error = git_reference_create_oid(&stash, repo, GIT_REFS_STASH_FILE, w_commit_oid, 1)) < 0)
+		goto cleanup;
+
+	if ((error = git_reflog_read(&reflog, stash)) < 0)
+		goto cleanup;
+
+	if ((error = git_reflog_append(reflog, w_commit_oid, stasher, message)) < 0)
+		goto cleanup;
+
+	if ((error = git_reflog_write(reflog)) < 0)
+		goto cleanup;
+
+	error = 0;
+
+cleanup:
+	git_reference_free(stash);
+	git_reflog_free(reflog);
+	return error;
+}
+
+static int is_dirty_cb(const char *path, unsigned int status, void *payload)
+{
+	GIT_UNUSED(path);
+	GIT_UNUSED(status);
+	GIT_UNUSED(payload);
+
+	return 1;
+}
+
+static int ensure_there_are_changes_to_stash(
+	git_repository *repo,
+	bool include_untracked_files,
+	bool include_ignored_files)
+{
+	int error;
+	git_status_options opts;
+
+	memset(&opts, 0, sizeof(opts));
+	opts.show  = GIT_STATUS_SHOW_INDEX_AND_WORKDIR;
+	if (include_untracked_files)
+		opts.flags = GIT_STATUS_OPT_INCLUDE_UNTRACKED |
+		GIT_STATUS_OPT_RECURSE_UNTRACKED_DIRS;
+
+	if (include_ignored_files)
+		opts.flags = GIT_STATUS_OPT_INCLUDE_IGNORED;
+
+	error = git_status_foreach_ext(repo, &opts, is_dirty_cb, NULL);
+
+	if (error == GIT_EUSER)
+		return 0;
+
+	if (!error)
+		return create_error(GIT_ENOTFOUND, "There is nothing to stash.");
+
+	return error;
+}
+
+static int reset_index_and_workdir(
+	git_repository *repo,
+	git_commit *commit,
+	bool remove_untracked)
+{
+	git_checkout_opts opts;
+
+	memset(&opts, 0, sizeof(git_checkout_opts));
+
+	opts.checkout_strategy = 
+		GIT_CHECKOUT_CREATE_MISSING | GIT_CHECKOUT_OVERWRITE_MODIFIED;
+
+	if (remove_untracked)
+		opts.checkout_strategy |= GIT_CHECKOUT_REMOVE_UNTRACKED;
+
+	return git_checkout_tree(repo, (git_object *)commit, &opts);
+}
+
+int git_stash_save(
+	git_oid *out,
+	git_repository *repo,
+	git_signature *stasher,
+	const char *message,
+	uint32_t flags)
+{
+	git_index *index = NULL;
+	git_commit *b_commit = NULL, *i_commit = NULL, *u_commit = NULL;
+	git_buf msg = GIT_BUF_INIT;
+	int error;
+
+	assert(out && repo && stasher);
+
+	if ((error = ensure_non_bare_repository(repo)) < 0)
+		return error;
+
+	if ((error = retrieve_base_commit_and_message(&b_commit, &msg, repo)) < 0)
+		goto cleanup;
+
+	if ((error = ensure_there_are_changes_to_stash(
+		repo,
+		(flags & GIT_STASH_INCLUDE_UNTRACKED) == GIT_STASH_INCLUDE_UNTRACKED,
+		(flags & GIT_STASH_INCLUDE_IGNORED) == GIT_STASH_INCLUDE_IGNORED)) < 0)
+		goto cleanup;
+
+	error = -1;
+
+	if (git_repository_index(&index, repo) < 0)
+		goto cleanup;
+
+	if (commit_index(&i_commit, index, stasher, git_buf_cstr(&msg), b_commit) < 0)
+		goto cleanup;
+
+	if ((flags & GIT_STASH_INCLUDE_UNTRACKED || flags & GIT_STASH_INCLUDE_IGNORED)
+		&& commit_untracked(&u_commit, index, stasher, git_buf_cstr(&msg), i_commit, flags) < 0)
+		goto cleanup;
+
+	if (prepare_worktree_commit_message(&msg, message) < 0)
+		goto cleanup;
+
+	if (commit_worktree(out, index, stasher, git_buf_cstr(&msg), i_commit, b_commit, u_commit) < 0)
+		goto cleanup;
+
+	git_buf_rtrim(&msg);
+	if (update_reflog(out, repo, stasher, git_buf_cstr(&msg)) < 0)
+		goto cleanup;
+
+	if (reset_index_and_workdir(
+		repo,
+		((flags & GIT_STASH_KEEP_INDEX) == GIT_STASH_KEEP_INDEX) ?
+			i_commit : b_commit,
+		(flags & GIT_STASH_INCLUDE_UNTRACKED) == GIT_STASH_INCLUDE_UNTRACKED) < 0)
+		goto cleanup;
+
+	error = 0;
+
+cleanup:
+	git_buf_free(&msg);
+	git_commit_free(i_commit);
+	git_commit_free(b_commit);
+	git_commit_free(u_commit);
+	git_index_free(index);
+	return error;
+}