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git-commit-vandalism/builtin/reset.c
Jeff King f932729cc7 memoize common git-path "constant" files 
One of the most common uses of git_path() is to pass a
constant, like git_path("MERGE_MSG"). This has two
drawbacks:

  1. The return value is a static buffer, and the lifetime
     is dependent on other calls to git_path, etc.

  2. There's no compile-time checking of the pathname. This
     is OK for a one-off (after all, we have to spell it
     correctly at least once), but many of these constant
     strings appear throughout the code.

This patch introduces a series of functions to "memoize"
these strings, which are essentially globals for the
lifetime of the program. We compute the value once, take
ownership of the buffer, and return the cached value for
subsequent calls.  cache.h provides a helper macro for
defining these functions as one-liners, and defines a few
common ones for global use.

Using a macro is a little bit gross, but it does nicely
document the purpose of the functions. If we need to touch
them all later (e.g., because we learned how to change the
git_dir variable at runtime, and need to invalidate all of
the stored values), it will be much easier to have the
complete list.

Note that the shared-global functions have separate, manual
declarations. We could do something clever with the macros
(e.g., expand it to a declaration in some places, and a
declaration _and_ a definition in path.c). But there aren't
that many, and it's probably better to stay away from
too-magical macros.

Likewise, if we abandon the C preprocessor in favor of
generating these with a script, we could get much fancier.
E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz".
But the small amount of saved typing is probably not worth
the resulting confusion to readers who want to grep for the
function's definition.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-10 15:37:14 -07:00

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/*
* "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 unsigned char *sha1, 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) {
unsigned char head_sha1[20];
if (get_sha1("HEAD", head_sha1))
return error(_("You do not have a valid HEAD."));
if (!fill_tree_descriptor(desc, head_sha1))
return error(_("Failed to find tree of HEAD."));
nr++;
opts.fn = twoway_merge;
}
if (!fill_tree_descriptor(desc + nr - 1, sha1))
return error(_("Failed to find tree of %s."), sha1_to_hex(sha1));
if (unpack_trees(nr, desc, &opts))
return -1;
if (reset_type == MIXED || reset_type == HARD) {
tree = parse_tree_indirect(sha1);
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.sha1, 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 += 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_sha1(one->sha1));
struct cache_entry *ce;
if (is_missing && !intent_to_add) {
remove_file_from_cache(one->path);
continue;
}
ce = make_cache_entry(one->mode, one->sha1, 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,
unsigned char *tree_sha1,
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_sha1, &opt))
return 1;
diffcore_std(&opt);
diff_flush(&opt);
free_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";
unsigned char unused[20];
/*
* 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)) ||
(argv[1] && !get_sha1_treeish(argv[0], unused))) {
/*
* 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 unsigned char *sha1)
{
int update_ref_status;
struct strbuf msg = STRBUF_INIT;
unsigned char *orig = NULL, sha1_orig[20],
*old_orig = NULL, sha1_old_orig[20];
if (!get_sha1("ORIG_HEAD", sha1_old_orig))
old_orig = sha1_old_orig;
if (!get_sha1("HEAD", sha1_orig)) {
orig = sha1_orig;
set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
UPDATE_REFS_MSG_ON_ERR);
} else if (old_orig)
delete_ref("ORIG_HEAD", old_orig, 0);
set_reflog_message(&msg, "updating HEAD", rev);
update_ref_status = update_ref(msg.buf, "HEAD", sha1, 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;
unsigned char sha1[20];
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", sha1);
if (unborn) {
/* reset on unborn branch: treat as reset to empty tree */
hashcpy(sha1, EMPTY_TREE_SHA1_BIN);
} else if (!pathspec.nr) {
struct commit *commit;
if (get_sha1_committish(rev, sha1))
die(_("Failed to resolve '%s' as a valid revision."), rev);
commit = lookup_commit_reference(sha1);
if (!commit)
die(_("Could not parse object '%s'."), rev);
hashcpy(sha1, commit->object.sha1);
} else {
struct tree *tree;
if (get_sha1_treeish(rev, sha1))
die(_("Failed to resolve '%s' as a valid tree."), rev);
tree = parse_tree_indirect(sha1);
if (!tree)
die(_("Could not parse object '%s'."), rev);
hashcpy(sha1, tree->object.sha1);
}
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, 1);
if (reset_type == MIXED) {
int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
if (read_from_tree(&pathspec, sha1, 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(sha1, reset_type, quiet);
if (reset_type == KEEP && !err)
err = reset_index(sha1, 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, sha1);
if (reset_type == HARD && !update_ref_status && !quiet)
print_new_head_line(lookup_commit_reference(sha1));
}
if (!pathspec.nr)
remove_branch_state();
return update_ref_status;
}
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