/*

* "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 | --merge] [-q] [<commit>]",

"git reset [--mixed] <commit> [--] <paths>...",

NULL

};

enum reset_type { MIXED, SOFT, HARD, MERGE, NONE };

static const char *reset_type_names[] = { "mixed", "soft", "hard", "merge", 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 reset_type, int quiet)

{

int i = 0;

const char *args[6];

args[i++] = "read-tree";

if (!quiet)

args[i++] = "-v";

switch (reset_type) {

case MERGE:

args[i++] = "-u";

args[i++] = "-m";

break;

case HARD:

args[i++] = "-u";

/* fallthrough */

default:

args[i++] = "--reset";

}

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 flags)

{

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_index(&the_index, (flags), NULL, NULL,

"Unstaged changes after reset:") ? 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);

if (!ce)

die("make_cache_entry failed for path '%s'",

one->path);

add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |

ADD_CACHE_OK_TO_REPLACE);

} else

remove_file_from_cache(one->path);

}

}

static int interactive_reset(const char *revision, const char **argv,

const char *prefix)

{

const char **pathspec = NULL;

if (*argv)

pathspec = get_pathspec(prefix, argv);

return run_add_interactive(revision, "--patch=reset", pathspec);

}

static int read_from_tree(const char *prefix, const char **argv,

unsigned char *tree_sha1, int refresh_flags)

{

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, refresh_flags);

}

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);

}

int cmd_reset(int argc, const char **argv, const char *prefix)

{

int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;

int patch_mode = 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_SET_INT(0, "merge", &reset_type,

"reset HEAD, index and working tree", MERGE),

OPT_BOOLEAN('q', NULL, &quiet,

"disable showing new HEAD in hard reset and progress message"),

OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),

OPT_END()

};

git_config(git_default_config, NULL);

argc = parse_options(argc, argv, prefix, options, git_reset_usage,

PARSE_OPT_KEEP_DASHDASH);

reflog_action = args_to_str(argv);

setenv("GIT_REFLOG_ACTION", reflog_action, 0);

/*

* Possible arguments are:

*

* git reset [-opts] <rev> <paths>...

* git reset [-opts] <rev> -- <paths>...

* git reset [-opts] -- <paths>...

* git reset [-opts] <paths>...

*

* At this point, argv[i] points immediately after [-opts].

*/

if (i < argc) {

if (!strcmp(argv[i], "--")) {

i++; /* reset to HEAD, possibly with paths */

} else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {

rev = argv[i];

i += 2;

}

/*

* Otherwise, argv[i] could be either <rev> or <paths> and

* has to be unambiguous.

*/

else if (!get_sha1(argv[i], sha1)) {

/*

* Ok, argv[i] looks like a rev; it should not

* be a filename.

*/

verify_non_filename(prefix, argv[i]);

rev = argv[i++];

} else {

/* Otherwise we treat this as a filename */

verify_filename(prefix, 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 (patch_mode) {

if (reset_type != NONE)

die("--patch is incompatible with --{hard,mixed,soft}");

return interactive_reset(rev, argv + i, prefix);

}

/* 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,

quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);

}

if (reset_type == NONE)

reset_type = MIXED; /* by default */

if ((reset_type == HARD || reset_type == MERGE)

&& !is_inside_work_tree())

die("%s reset requires a work tree",

reset_type_names[reset_type]);

/* 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, 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, 0);

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,

quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);

break;

}

remove_branch_state();

free(reflog_action);

return update_ref_status;

}