1 files changed, 375 insertions, 0 deletions
diff --git a/builtin/worktree.c b/builtin/worktree.c
new file mode 100644
index 0000000000..71bb770f7a
--- /dev/null
+++ b/builtin/worktree.c
@@ -0,0 +1,375 @@
+#include "cache.h"
+#include "builtin.h"
+#include "dir.h"
+#include "parse-options.h"
+#include "argv-array.h"
+#include "branch.h"
+#include "refs.h"
+#include "run-command.h"
+#include "sigchain.h"
+#include "refs.h"
+
+static const char * const worktree_usage[] = {
+	N_("git worktree add [<options>] <path> <branch>"),
+	N_("git worktree prune [<options>]"),
+	NULL
+};
+
+struct add_opts {
+	int force;
+	int detach;
+	const char *new_branch;
+	int force_new_branch;
+};
+
+static int show_only;
+static int verbose;
+static unsigned long expire;
+
+static int prune_worktree(const char *id, struct strbuf *reason)
+{
+	struct stat st;
+	char *path;
+	int fd, len;
+
+	if (!is_directory(git_path("worktrees/%s", id))) {
+		strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
+		return 1;
+	}
+	if (file_exists(git_path("worktrees/%s/locked", id)))
+		return 0;
+	if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
+		strbuf_addf(reason, _("Removing worktrees/%s: gitdir file does not exist"), id);
+		return 1;
+	}
+	fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
+	if (fd < 0) {
+		strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
+			    id, strerror(errno));
+		return 1;
+	}
+	len = st.st_size;
+	path = xmalloc(len + 1);
+	read_in_full(fd, path, len);
+	close(fd);
+	while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
+		len--;
+	if (!len) {
+		strbuf_addf(reason, _("Removing worktrees/%s: invalid gitdir file"), id);
+		free(path);
+		return 1;
+	}
+	path[len] = '\0';
+	if (!file_exists(path)) {
+		struct stat st_link;
+		free(path);
+		/*
+		 * the repo is moved manually and has not been
+		 * accessed since?
+		 */
+		if (!stat(git_path("worktrees/%s/link", id), &st_link) &&
+		    st_link.st_nlink > 1)
+			return 0;
+		if (st.st_mtime <= expire) {
+			strbuf_addf(reason, _("Removing worktrees/%s: gitdir file points to non-existent location"), id);
+			return 1;
+		} else {
+			return 0;
+		}
+	}
+	free(path);
+	return 0;
+}
+
+static void prune_worktrees(void)
+{
+	struct strbuf reason = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	DIR *dir = opendir(git_path("worktrees"));
+	struct dirent *d;
+	int ret;
+	if (!dir)
+		return;
+	while ((d = readdir(dir)) != NULL) {
+		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+		strbuf_reset(&reason);
+		if (!prune_worktree(d->d_name, &reason))
+			continue;
+		if (show_only || verbose)
+			printf("%s\n", reason.buf);
+		if (show_only)
+			continue;
+		strbuf_reset(&path);
+		strbuf_addstr(&path, git_path("worktrees/%s", d->d_name));
+		ret = remove_dir_recursively(&path, 0);
+		if (ret < 0 && errno == ENOTDIR)
+			ret = unlink(path.buf);
+		if (ret)
+			error(_("failed to remove: %s"), strerror(errno));
+	}
+	closedir(dir);
+	if (!show_only)
+		rmdir(git_path("worktrees"));
+	strbuf_release(&reason);
+	strbuf_release(&path);
+}
+
+static int prune(int ac, const char **av, const char *prefix)
+{
+	struct option options[] = {
+		OPT__DRY_RUN(&show_only, N_("do not remove, show only")),
+		OPT__VERBOSE(&verbose, N_("report pruned objects")),
+		OPT_EXPIRY_DATE(0, "expire", &expire,
+				N_("expire objects older than <time>")),
+		OPT_END()
+	};
+
+	expire = ULONG_MAX;
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (ac)
+		usage_with_options(worktree_usage, options);
+	prune_worktrees();
+	return 0;
+}
+
+static char *junk_work_tree;
+static char *junk_git_dir;
+static int is_junk;
+static pid_t junk_pid;
+
+static void remove_junk(void)
+{
+	struct strbuf sb = STRBUF_INIT;
+	if (!is_junk || getpid() != junk_pid)
+		return;
+	if (junk_git_dir) {
+		strbuf_addstr(&sb, junk_git_dir);
+		remove_dir_recursively(&sb, 0);
+		strbuf_reset(&sb);
+	}
+	if (junk_work_tree) {
+		strbuf_addstr(&sb, junk_work_tree);
+		remove_dir_recursively(&sb, 0);
+	}
+	strbuf_release(&sb);
+}
+
+static void remove_junk_on_signal(int signo)
+{
+	remove_junk();
+	sigchain_pop(signo);
+	raise(signo);
+}
+
+static const char *worktree_basename(const char *path, int *olen)
+{
+	const char *name;
+	int len;
+
+	len = strlen(path);
+	while (len && is_dir_sep(path[len - 1]))
+		len--;
+
+	for (name = path + len - 1; name > path; name--)
+		if (is_dir_sep(*name)) {
+			name++;
+			break;
+		}
+
+	*olen = len;
+	return name;
+}
+
+static int add_worktree(const char *path, const char *refname,
+			const struct add_opts *opts)
+{
+	struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
+	const char *name;
+	struct stat st;
+	struct child_process cp;
+	struct argv_array child_env = ARGV_ARRAY_INIT;
+	int counter = 0, len, ret;
+	struct strbuf symref = STRBUF_INIT;
+	struct commit *commit = NULL;
+
+	if (file_exists(path) && !is_empty_dir(path))
+		die(_("'%s' already exists"), path);
+
+	/* is 'refname' a branch or commit? */
+	if (opts->force_new_branch) /* definitely a branch */
+		;
+	else if (!opts->detach && !strbuf_check_branch_ref(&symref, refname) &&
+		 ref_exists(symref.buf)) { /* it's a branch */
+		if (!opts->force)
+			die_if_checked_out(symref.buf);
+	} else { /* must be a commit */
+		commit = lookup_commit_reference_by_name(refname);
+		if (!commit)
+			die(_("invalid reference: %s"), refname);
+	}
+
+	name = worktree_basename(path, &len);
+	strbuf_addstr(&sb_repo,
+		      git_path("worktrees/%.*s", (int)(path + len - name), name));
+	len = sb_repo.len;
+	if (safe_create_leading_directories_const(sb_repo.buf))
+		die_errno(_("could not create leading directories of '%s'"),
+			  sb_repo.buf);
+	while (!stat(sb_repo.buf, &st)) {
+		counter++;
+		strbuf_setlen(&sb_repo, len);
+		strbuf_addf(&sb_repo, "%d", counter);
+	}
+	name = strrchr(sb_repo.buf, '/') + 1;
+
+	junk_pid = getpid();
+	atexit(remove_junk);
+	sigchain_push_common(remove_junk_on_signal);
+
+	if (mkdir(sb_repo.buf, 0777))
+		die_errno(_("could not create directory of '%s'"), sb_repo.buf);
+	junk_git_dir = xstrdup(sb_repo.buf);
+	is_junk = 1;
+
+	/*
+	 * lock the incomplete repo so prune won't delete it, unlock
+	 * after the preparation is over.
+	 */
+	strbuf_addf(&sb, "%s/locked", sb_repo.buf);
+	write_file(sb.buf, "initializing");
+
+	strbuf_addf(&sb_git, "%s/.git", path);
+	if (safe_create_leading_directories_const(sb_git.buf))
+		die_errno(_("could not create leading directories of '%s'"),
+			  sb_git.buf);
+	junk_work_tree = xstrdup(path);
+
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
+	write_file(sb.buf, "%s", real_path(sb_git.buf));
+	write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
+		   real_path(get_git_common_dir()), name);
+	/*
+	 * This is to keep resolve_ref() happy. We need a valid HEAD
+	 * or is_git_directory() will reject the directory. Any value which
+	 * looks like an object ID will do since it will be immediately
+	 * replaced by the symbolic-ref or update-ref invocation in the new
+	 * worktree.
+	 */
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
+	write_file(sb.buf, "0000000000000000000000000000000000000000");
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
+	write_file(sb.buf, "../..");
+
+	fprintf_ln(stderr, _("Preparing %s (identifier %s)"), path, name);
+
+	argv_array_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
+	argv_array_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
+	memset(&cp, 0, sizeof(cp));
+	cp.git_cmd = 1;
+
+	if (commit)
+		argv_array_pushl(&cp.args, "update-ref", "HEAD",
+				 sha1_to_hex(commit->object.sha1), NULL);
+	else
+		argv_array_pushl(&cp.args, "symbolic-ref", "HEAD",
+				 symref.buf, NULL);
+	cp.env = child_env.argv;
+	ret = run_command(&cp);
+	if (ret)
+		goto done;
+
+	cp.argv = NULL;
+	argv_array_clear(&cp.args);
+	argv_array_pushl(&cp.args, "reset", "--hard", NULL);
+	cp.env = child_env.argv;
+	ret = run_command(&cp);
+	if (!ret) {
+		is_junk = 0;
+		free(junk_work_tree);
+		free(junk_git_dir);
+		junk_work_tree = NULL;
+		junk_git_dir = NULL;
+	}
+done:
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%s/locked", sb_repo.buf);
+	unlink_or_warn(sb.buf);
+	argv_array_clear(&child_env);
+	strbuf_release(&sb);
+	strbuf_release(&symref);
+	strbuf_release(&sb_repo);
+	strbuf_release(&sb_git);
+	return ret;
+}
+
+static int add(int ac, const char **av, const char *prefix)
+{
+	struct add_opts opts;
+	const char *new_branch_force = NULL;
+	const char *path, *branch;
+	struct option options[] = {
+		OPT__FORCE(&opts.force, N_("checkout <branch> even if already checked out in other worktree")),
+		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
+			   N_("create a new branch")),
+		OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
+			   N_("create or reset a branch")),
+		OPT_BOOL(0, "detach", &opts.detach, N_("detach HEAD at named commit")),
+		OPT_END()
+	};
+
+	memset(&opts, 0, sizeof(opts));
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
+		die(_("-b, -B, and --detach are mutually exclusive"));
+	if (ac < 1 || ac > 2)
+		usage_with_options(worktree_usage, options);
+
+	path = prefix ? prefix_filename(prefix, strlen(prefix), av[0]) : av[0];
+	branch = ac < 2 ? "HEAD" : av[1];
+
+	opts.force_new_branch = !!new_branch_force;
+	if (opts.force_new_branch)
+		opts.new_branch = new_branch_force;
+
+	if (ac < 2 && !opts.new_branch && !opts.detach) {
+		int n;
+		const char *s = worktree_basename(path, &n);
+		opts.new_branch = xstrndup(s, n);
+	}
+
+	if (opts.new_branch) {
+		struct child_process cp;
+		memset(&cp, 0, sizeof(cp));
+		cp.git_cmd = 1;
+		argv_array_push(&cp.args, "branch");
+		if (opts.force_new_branch)
+			argv_array_push(&cp.args, "--force");
+		argv_array_push(&cp.args, opts.new_branch);
+		argv_array_push(&cp.args, branch);
+		if (run_command(&cp))
+			return -1;
+		branch = opts.new_branch;
+	}
+
+	return add_worktree(path, branch, &opts);
+}
+
+int cmd_worktree(int ac, const char **av, const char *prefix)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+
+	if (ac < 2)
+		usage_with_options(worktree_usage, options);
+	if (!strcmp(av[1], "add"))
+		return add(ac - 1, av + 1, prefix);
+	if (!strcmp(av[1], "prune"))
+		return prune(ac - 1, av + 1, prefix);
+	usage_with_options(worktree_usage, options);
+}