1 files changed, 269 insertions, 0 deletions
diff --git a/builtin-reset.c b/builtin-reset.c
new file mode 100644
index 0000000000..f34acb1915
--- /dev/null
+++ b/builtin-reset.c
@@ -0,0 +1,269 @@
+/*
+ * "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 "cache.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"
+
+static const char * const git_reset_usage[] = {
+	"git-reset [--mixed | --soft | --hard] [-q] [<commit>]",
+	"git-reset [--mixed] <commit> [--] <paths>...",
+	NULL
+};
+
+static char *args_to_str(const char **argv)
+{
+	char *buf = NULL;
+	unsigned long len, space = 0, nr = 0;
+
+	for (; *argv; argv++) {
+		len = strlen(*argv);
+		ALLOC_GROW(buf, nr + 1 + len, space);
+		if (nr)
+			buf[nr++] = ' ';
+		memcpy(buf + nr, *argv, len);
+		nr += len;
+	}
+	ALLOC_GROW(buf, nr + 1, space);
+	buf[nr] = '\0';
+
+	return buf;
+}
+
+static inline int is_merge(void)
+{
+	return !access(git_path("MERGE_HEAD"), F_OK);
+}
+
+static int reset_index_file(const unsigned char *sha1, int is_hard_reset, int quiet)
+{
+	int i = 0;
+	const char *args[6];
+
+	args[i++] = "read-tree";
+	if (!quiet)
+		args[i++] = "-v";
+	args[i++] = "--reset";
+	if (is_hard_reset)
+		args[i++] = "-u";
+	args[i++] = sha1_to_hex(sha1);
+	args[i] = NULL;
+
+	return run_command_v_opt(args, RUN_GIT_CMD);
+}
+
+static void print_new_head_line(struct commit *commit)
+{
+	const char *hex, *body;
+
+	hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
+	printf("HEAD is now at %s", hex);
+	body = strstr(commit->buffer, "\n\n");
+	if (body) {
+		const char *eol;
+		size_t len;
+		body += 2;
+		eol = strchr(body, '\n');
+		len = eol ? eol - body : strlen(body);
+		printf(" %.*s\n", (int) len, body);
+	}
+	else
+		printf("\n");
+}
+
+static int update_index_refresh(int fd, struct lock_file *index_lock)
+{
+	int result;
+
+	if (!index_lock) {
+		index_lock = xcalloc(1, sizeof(struct lock_file));
+		fd = hold_locked_index(index_lock, 1);
+	}
+
+	if (read_cache() < 0)
+		return error("Could not read index");
+	result = refresh_cache(0) ? 1 : 0;
+	if (write_cache(fd, active_cache, active_nr) ||
+			commit_locked_index(index_lock))
+		return error ("Could not refresh index");
+	return result;
+}
+
+static void update_index_from_diff(struct diff_queue_struct *q,
+		struct diff_options *opt, void *data)
+{
+	int i;
+	int *discard_flag = data;
+
+	/* do_diff_cache() mangled the index */
+	discard_cache();
+	*discard_flag = 1;
+	read_cache();
+
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filespec *one = q->queue[i]->one;
+		if (one->mode) {
+			struct cache_entry *ce;
+			ce = make_cache_entry(one->mode, one->sha1, one->path,
+				0, 0);
+			add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
+				ADD_CACHE_OK_TO_REPLACE);
+		} else
+			remove_file_from_cache(one->path);
+	}
+}
+
+static int read_from_tree(const char *prefix, const char **argv,
+		unsigned char *tree_sha1)
+{
+	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+	int index_fd, index_was_discarded = 0;
+	struct diff_options opt;
+
+	memset(&opt, 0, sizeof(opt));
+	diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
+	opt.output_format = DIFF_FORMAT_CALLBACK;
+	opt.format_callback = update_index_from_diff;
+	opt.format_callback_data = &index_was_discarded;
+
+	index_fd = hold_locked_index(lock, 1);
+	index_was_discarded = 0;
+	read_cache();
+	if (do_diff_cache(tree_sha1, &opt))
+		return 1;
+	diffcore_std(&opt);
+	diff_flush(&opt);
+	diff_tree_release_paths(&opt);
+
+	if (!index_was_discarded)
+		/* The index is still clobbered from do_diff_cache() */
+		discard_cache();
+	return update_index_refresh(index_fd, lock);
+}
+
+static void prepend_reflog_action(const char *action, char *buf, size_t size)
+{
+	const char *sep = ": ";
+	const char *rla = getenv("GIT_REFLOG_ACTION");
+	if (!rla)
+		rla = sep = "";
+	if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
+		warning("Reflog action message too long: %.*s...", 50, buf);
+}
+
+enum reset_type { MIXED, SOFT, HARD, NONE };
+static const char *reset_type_names[] = { "mixed", "soft", "hard", NULL };
+
+int cmd_reset(int argc, const char **argv, const char *prefix)
+{
+	int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
+	const char *rev = "HEAD";
+	unsigned char sha1[20], *orig = NULL, sha1_orig[20],
+				*old_orig = NULL, sha1_old_orig[20];
+	struct commit *commit;
+	char *reflog_action, msg[1024];
+	const struct option options[] = {
+		OPT_SET_INT(0, "mixed", &reset_type,
+						"reset HEAD and index", MIXED),
+		OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
+		OPT_SET_INT(0, "hard", &reset_type,
+				"reset HEAD, index and working tree", HARD),
+		OPT_BOOLEAN('q', NULL, &quiet,
+				"disable showing new HEAD in hard reset and progress message"),
+		OPT_END()
+	};
+
+	git_config(git_default_config, NULL);
+
+	argc = parse_options(argc, argv, options, git_reset_usage,
+						PARSE_OPT_KEEP_DASHDASH);
+	reflog_action = args_to_str(argv);
+	setenv("GIT_REFLOG_ACTION", reflog_action, 0);
+
+	if (i < argc && strcmp(argv[i], "--"))
+		rev = argv[i++];
+
+	if (get_sha1(rev, sha1))
+		die("Failed to resolve '%s' as a valid ref.", rev);
+
+	commit = lookup_commit_reference(sha1);
+	if (!commit)
+		die("Could not parse object '%s'.", rev);
+	hashcpy(sha1, commit->object.sha1);
+
+	if (i < argc && !strcmp(argv[i], "--"))
+		i++;
+
+	/* 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 (i < argc) {
+		if (reset_type == MIXED)
+			warning("--mixed option is deprecated with paths.");
+		else if (reset_type != NONE)
+			die("Cannot do %s reset with paths.",
+					reset_type_names[reset_type]);
+		return read_from_tree(prefix, argv + i, sha1);
+	}
+	if (reset_type == NONE)
+		reset_type = MIXED; /* by default */
+
+	if (reset_type == HARD && is_bare_repository())
+		die("hard reset makes no sense in a bare repository");
+
+	/* 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) {
+		if (is_merge() || read_cache() < 0 || unmerged_cache())
+			die("Cannot do a soft reset in the middle of a merge.");
+	}
+	else if (reset_index_file(sha1, (reset_type == HARD), quiet))
+		die("Could not reset index file to revision '%s'.", rev);
+
+	/* Any resets update HEAD to the head being switched to,
+	 * saving the previous head in ORIG_HEAD before. */
+	if (!get_sha1("ORIG_HEAD", sha1_old_orig))
+		old_orig = sha1_old_orig;
+	if (!get_sha1("HEAD", sha1_orig)) {
+		orig = sha1_orig;
+		prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
+		update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
+	}
+	else if (old_orig)
+		delete_ref("ORIG_HEAD", old_orig);
+	prepend_reflog_action("updating HEAD", msg, sizeof(msg));
+	update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
+
+	switch (reset_type) {
+	case HARD:
+		if (!update_ref_status && !quiet)
+			print_new_head_line(commit);
+		break;
+	case SOFT: /* Nothing else to do. */
+		break;
+	case MIXED: /* Report what has not been updated. */
+		update_index_refresh(0, NULL);
+		break;
+	}
+
+	remove_branch_state();
+
+	free(reflog_action);
+
+	return update_ref_status;
+}