1 files changed, 389 insertions, 0 deletions

diff --git a/builtin/reset.c b/builtin/reset.c
new file mode 100644
index 0000000000..fc3b906c47
--- /dev/null
+++ b/builtin/reset.c
@@ -0,0 +1,389 @@
+/*
+ * "git reset" builtin command
+ *
+ * Copyright (c) 2007 Carlos Rica
+ *
+ * Based on git-reset.sh, which is
+ *
+ * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano
+ */
+#include "builtin.h"
+#include "lockfile.h"
+#include "tag.h"
+#include "object.h"
+#include "commit.h"
+#include "run-command.h"
+#include "refs.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "tree.h"
+#include "branch.h"
+#include "parse-options.h"
+#include "unpack-trees.h"
+#include "cache-tree.h"
+
+static const char * const git_reset_usage[] = {
+	N_("git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]"),
+	N_("git reset [-q] [<tree-ish>] [--] <paths>..."),
+	N_("git reset --patch [<tree-ish>] [--] [<paths>...]"),
+	NULL
+};
+
+enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };
+static const char *reset_type_names[] = {
+	N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL
+};
+
+static inline int is_merge(void)
+{
+	return !access(git_path_merge_head(), F_OK);
+}
+
+static int reset_index(const struct object_id *oid, int reset_type, int quiet)
+{
+	int nr = 1;
+	struct tree_desc desc[2];
+	struct tree *tree;
+	struct unpack_trees_options opts;
+
+	memset(&opts, 0, sizeof(opts));
+	opts.head_idx = 1;
+	opts.src_index = &the_index;
+	opts.dst_index = &the_index;
+	opts.fn = oneway_merge;
+	opts.merge = 1;
+	if (!quiet)
+		opts.verbose_update = 1;
+	switch (reset_type) {
+	case KEEP:
+	case MERGE:
+		opts.update = 1;
+		break;
+	case HARD:
+		opts.update = 1;
+		/* fallthrough */
+	default:
+		opts.reset = 1;
+	}
+
+	read_cache_unmerged();
+
+	if (reset_type == KEEP) {
+		struct object_id head_oid;
+		if (get_oid("HEAD", &head_oid))
+			return error(_("You do not have a valid HEAD."));
+		if (!fill_tree_descriptor(desc, head_oid.hash))
+			return error(_("Failed to find tree of HEAD."));
+		nr++;
+		opts.fn = twoway_merge;
+	}
+
+	if (!fill_tree_descriptor(desc + nr - 1, oid->hash))
+		return error(_("Failed to find tree of %s."), oid_to_hex(oid));
+	if (unpack_trees(nr, desc, &opts))
+		return -1;
+
+	if (reset_type == MIXED || reset_type == HARD) {
+		tree = parse_tree_indirect(oid->hash);
+		prime_cache_tree(&the_index, tree);
+	}
+
+	return 0;
+}
+
+static void print_new_head_line(struct commit *commit)
+{
+	const char *hex, *body;
+	const char *msg;
+
+	hex = find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
+	printf(_("HEAD is now at %s"), hex);
+	msg = logmsg_reencode(commit, NULL, get_log_output_encoding());
+	body = strstr(msg, "\n\n");
+	if (body) {
+		const char *eol;
+		size_t len;
+		body = skip_blank_lines(body + 2);
+		eol = strchr(body, '\n');
+		len = eol ? eol - body : strlen(body);
+		printf(" %.*s\n", (int) len, body);
+	}
+	else
+		printf("\n");
+	unuse_commit_buffer(commit, msg);
+}
+
+static void update_index_from_diff(struct diff_queue_struct *q,
+		struct diff_options *opt, void *data)
+{
+	int i;
+	int intent_to_add = *(int *)data;
+
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filespec *one = q->queue[i]->one;
+		int is_missing = !(one->mode && !is_null_oid(&one->oid));
+		struct cache_entry *ce;
+
+		if (is_missing && !intent_to_add) {
+			remove_file_from_cache(one->path);
+			continue;
+		}
+
+		ce = make_cache_entry(one->mode, one->oid.hash, one->path,
+				      0, 0);
+		if (!ce)
+			die(_("make_cache_entry failed for path '%s'"),
+			    one->path);
+		if (is_missing) {
+			ce->ce_flags |= CE_INTENT_TO_ADD;
+			set_object_name_for_intent_to_add_entry(ce);
+		}
+		add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
+	}
+}
+
+static int read_from_tree(const struct pathspec *pathspec,
+			  struct object_id *tree_oid,
+			  int intent_to_add)
+{
+	struct diff_options opt;
+
+	memset(&opt, 0, sizeof(opt));
+	copy_pathspec(&opt.pathspec, pathspec);
+	opt.output_format = DIFF_FORMAT_CALLBACK;
+	opt.format_callback = update_index_from_diff;
+	opt.format_callback_data = &intent_to_add;
+
+	if (do_diff_cache(tree_oid->hash, &opt))
+		return 1;
+	diffcore_std(&opt);
+	diff_flush(&opt);
+	clear_pathspec(&opt.pathspec);
+
+	return 0;
+}
+
+static void set_reflog_message(struct strbuf *sb, const char *action,
+			       const char *rev)
+{
+	const char *rla = getenv("GIT_REFLOG_ACTION");
+
+	strbuf_reset(sb);
+	if (rla)
+		strbuf_addf(sb, "%s: %s", rla, action);
+	else if (rev)
+		strbuf_addf(sb, "reset: moving to %s", rev);
+	else
+		strbuf_addf(sb, "reset: %s", action);
+}
+
+static void die_if_unmerged_cache(int reset_type)
+{
+	if (is_merge() || unmerged_cache())
+		die(_("Cannot do a %s reset in the middle of a merge."),
+		    _(reset_type_names[reset_type]));
+
+}
+
+static void parse_args(struct pathspec *pathspec,
+		       const char **argv, const char *prefix,
+		       int patch_mode,
+		       const char **rev_ret)
+{
+	const char *rev = "HEAD";
+	struct object_id unused;
+	/*
+	 * Possible arguments are:
+	 *
+	 * git reset [-opts] [<rev>]
+	 * git reset [-opts] <tree> [<paths>...]
+	 * git reset [-opts] <tree> -- [<paths>...]
+	 * git reset [-opts] -- [<paths>...]
+	 * git reset [-opts] <paths>...
+	 *
+	 * At this point, argv points immediately after [-opts].
+	 */
+
+	if (argv[0]) {
+		if (!strcmp(argv[0], "--")) {
+			argv++; /* reset to HEAD, possibly with paths */
+		} else if (argv[1] && !strcmp(argv[1], "--")) {
+			rev = argv[0];
+			argv += 2;
+		}
+		/*
+		 * Otherwise, argv[0] could be either <rev> or <paths> and
+		 * has to be unambiguous. If there is a single argument, it
+		 * can not be a tree
+		 */
+		else if ((!argv[1] && !get_sha1_committish(argv[0], unused.hash)) ||
+			 (argv[1] && !get_sha1_treeish(argv[0], unused.hash))) {
+			/*
+			 * Ok, argv[0] looks like a commit/tree; it should not
+			 * be a filename.
+			 */
+			verify_non_filename(prefix, argv[0]);
+			rev = *argv++;
+		} else {
+			/* Otherwise we treat this as a filename */
+			verify_filename(prefix, argv[0], 1);
+		}
+	}
+	*rev_ret = rev;
+
+	if (read_cache() < 0)
+		die(_("index file corrupt"));
+
+	parse_pathspec(pathspec, 0,
+		       PATHSPEC_PREFER_FULL |
+		       PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP |
+		       (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
+		       prefix, argv);
+}
+
+static int reset_refs(const char *rev, const struct object_id *oid)
+{
+	int update_ref_status;
+	struct strbuf msg = STRBUF_INIT;
+	struct object_id *orig = NULL, oid_orig,
+		*old_orig = NULL, oid_old_orig;
+
+	if (!get_oid("ORIG_HEAD", &oid_old_orig))
+		old_orig = &oid_old_orig;
+	if (!get_oid("HEAD", &oid_orig)) {
+		orig = &oid_orig;
+		set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
+		update_ref_oid(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
+			   UPDATE_REFS_MSG_ON_ERR);
+	} else if (old_orig)
+		delete_ref(NULL, "ORIG_HEAD", old_orig->hash, 0);
+	set_reflog_message(&msg, "updating HEAD", rev);
+	update_ref_status = update_ref_oid(msg.buf, "HEAD", oid, orig, 0,
+				       UPDATE_REFS_MSG_ON_ERR);
+	strbuf_release(&msg);
+	return update_ref_status;
+}
+
+int cmd_reset(int argc, const char **argv, const char *prefix)
+{
+	int reset_type = NONE, update_ref_status = 0, quiet = 0;
+	int patch_mode = 0, unborn;
+	const char *rev;
+	struct object_id oid;
+	struct pathspec pathspec;
+	int intent_to_add = 0;
+	const struct option options[] = {
+		OPT__QUIET(&quiet, N_("be quiet, only report errors")),
+		OPT_SET_INT(0, "mixed", &reset_type,
+						N_("reset HEAD and index"), MIXED),
+		OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
+		OPT_SET_INT(0, "hard", &reset_type,
+				N_("reset HEAD, index and working tree"), HARD),
+		OPT_SET_INT(0, "merge", &reset_type,
+				N_("reset HEAD, index and working tree"), MERGE),
+		OPT_SET_INT(0, "keep", &reset_type,
+				N_("reset HEAD but keep local changes"), KEEP),
+		OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),
+		OPT_BOOL('N', "intent-to-add", &intent_to_add,
+				N_("record only the fact that removed paths will be added later")),
+		OPT_END()
+	};
+
+	git_config(git_default_config, NULL);
+
+	argc = parse_options(argc, argv, prefix, options, git_reset_usage,
+						PARSE_OPT_KEEP_DASHDASH);
+	parse_args(&pathspec, argv, prefix, patch_mode, &rev);
+
+	unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", oid.hash);
+	if (unborn) {
+		/* reset on unborn branch: treat as reset to empty tree */
+		hashcpy(oid.hash, EMPTY_TREE_SHA1_BIN);
+	} else if (!pathspec.nr) {
+		struct commit *commit;
+		if (get_sha1_committish(rev, oid.hash))
+			die(_("Failed to resolve '%s' as a valid revision."), rev);
+		commit = lookup_commit_reference(oid.hash);
+		if (!commit)
+			die(_("Could not parse object '%s'."), rev);
+		oidcpy(&oid, &commit->object.oid);
+	} else {
+		struct tree *tree;
+		if (get_sha1_treeish(rev, oid.hash))
+			die(_("Failed to resolve '%s' as a valid tree."), rev);
+		tree = parse_tree_indirect(oid.hash);
+		if (!tree)
+			die(_("Could not parse object '%s'."), rev);
+		oidcpy(&oid, &tree->object.oid);
+	}
+
+	if (patch_mode) {
+		if (reset_type != NONE)
+			die(_("--patch is incompatible with --{hard,mixed,soft}"));
+		return run_add_interactive(rev, "--patch=reset", &pathspec);
+	}
+
+	/* git reset tree [--] paths... can be used to
+	 * load chosen paths from the tree into the index without
+	 * affecting the working tree nor HEAD. */
+	if (pathspec.nr) {
+		if (reset_type == MIXED)
+			warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
+		else if (reset_type != NONE)
+			die(_("Cannot do %s reset with paths."),
+					_(reset_type_names[reset_type]));
+	}
+	if (reset_type == NONE)
+		reset_type = MIXED; /* by default */
+
+	if (reset_type != SOFT && (reset_type != MIXED || get_git_work_tree()))
+		setup_work_tree();
+
+	if (reset_type == MIXED && is_bare_repository())
+		die(_("%s reset is not allowed in a bare repository"),
+		    _(reset_type_names[reset_type]));
+
+	if (intent_to_add && reset_type != MIXED)
+		die(_("-N can only be used with --mixed"));
+
+	/* Soft reset does not touch the index file nor the working tree
+	 * at all, but requires them in a good order.  Other resets reset
+	 * the index file to the tree object we are switching to. */
+	if (reset_type == SOFT || reset_type == KEEP)
+		die_if_unmerged_cache(reset_type);
+
+	if (reset_type != SOFT) {
+		struct lock_file *lock = xcalloc(1, sizeof(*lock));
+		hold_locked_index(lock, LOCK_DIE_ON_ERROR);
+		if (reset_type == MIXED) {
+			int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
+			if (read_from_tree(&pathspec, &oid, intent_to_add))
+				return 1;
+			if (get_git_work_tree())
+				refresh_index(&the_index, flags, NULL, NULL,
+					      _("Unstaged changes after reset:"));
+		} else {
+			int err = reset_index(&oid, reset_type, quiet);
+			if (reset_type == KEEP && !err)
+				err = reset_index(&oid, MIXED, quiet);
+			if (err)
+				die(_("Could not reset index file to revision '%s'."), rev);
+		}
+
+		if (write_locked_index(&the_index, lock, COMMIT_LOCK))
+			die(_("Could not write new index file."));
+	}
+
+	if (!pathspec.nr && !unborn) {
+		/* Any resets without paths update HEAD to the head being
+		 * switched to, saving the previous head in ORIG_HEAD before. */
+		update_ref_status = reset_refs(rev, &oid);
+
+		if (reset_type == HARD && !update_ref_status && !quiet)
+			print_new_head_line(lookup_commit_reference(oid.hash));
+	}
+	if (!pathspec.nr)
+		remove_branch_state();
+
+	return update_ref_status;
+}