git/builtin-revert.c

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#include "cache.h"
#include "builtin.h"
#include "object.h"
#include "commit.h"
#include "tag.h"
#include "wt-status.h"
#include "run-command.h"
#include "exec_cmd.h"
#include "utf8.h"
/*
* This implements the builtins revert and cherry-pick.
*
* Copyright (c) 2007 Johannes E. Schindelin
*
* Based on git-revert.sh, which is
*
* Copyright (c) 2005 Linus Torvalds
* Copyright (c) 2005 Junio C Hamano
*/
static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] <commit-ish>";
static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";
static int edit;
static int replay;
static enum { REVERT, CHERRY_PICK } action;
static int no_commit;
static struct commit *commit;
static int needed_deref;
static const char *me;
#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
static void parse_options(int argc, const char **argv)
{
const char *usage_str = action == REVERT ?
revert_usage : cherry_pick_usage;
unsigned char sha1[20];
const char *arg;
int i;
if (argc < 2)
usage(usage_str);
for (i = 1; i < argc; i++) {
arg = argv[i];
if (arg[0] != '-')
break;
if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
no_commit = 1;
else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
edit = 1;
else if (!strcmp(arg, "--no-edit"))
edit = 0;
else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
"to-expose-my-private-commit-object-name"))
replay = 0;
else if (strcmp(arg, "-r"))
usage(usage_str);
}
if (i != argc - 1)
usage(usage_str);
arg = argv[argc - 1];
if (get_sha1(arg, sha1))
die ("Cannot find '%s'", arg);
commit = (struct commit *)parse_object(sha1);
if (!commit)
die ("Could not find %s", sha1_to_hex(sha1));
if (commit->object.type == OBJ_TAG) {
commit = (struct commit *)
deref_tag((struct object *)commit, arg, strlen(arg));
needed_deref = 1;
}
if (commit->object.type != OBJ_COMMIT)
die ("'%s' does not point to a commit", arg);
}
static char *get_oneline(const char *message)
{
char *result;
const char *p = message, *abbrev, *eol;
int abbrev_len, oneline_len;
if (!p)
die ("Could not read commit message of %s",
sha1_to_hex(commit->object.sha1));
while (*p && (*p != '\n' || p[1] != '\n'))
p++;
if (*p) {
p += 2;
for (eol = p + 1; *eol && *eol != '\n'; eol++)
; /* do nothing */
} else
eol = p;
abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
abbrev_len = strlen(abbrev);
oneline_len = eol - p;
result = xmalloc(abbrev_len + 5 + oneline_len);
memcpy(result, abbrev, abbrev_len);
memcpy(result + abbrev_len, "... ", 4);
memcpy(result + abbrev_len + 4, p, oneline_len);
result[abbrev_len + 4 + oneline_len] = '\0';
return result;
}
static char *get_encoding(const char *message)
{
const char *p = message, *eol;
if (!p)
die ("Could not read commit message of %s",
sha1_to_hex(commit->object.sha1));
while (*p && *p != '\n') {
for (eol = p + 1; *eol && *eol != '\n'; eol++)
; /* do nothing */
if (!prefixcmp(p, "encoding ")) {
char *result = xmalloc(eol - 8 - p);
strlcpy(result, p + 9, eol - 8 - p);
return result;
}
p = eol;
if (*p == '\n')
p++;
}
return NULL;
}
static struct lock_file msg_file;
static int msg_fd;
static void add_to_msg(const char *string)
{
int len = strlen(string);
if (write_in_full(msg_fd, string, len) < 0)
die ("Could not write to MERGE_MSG");
}
static void add_message_to_msg(const char *message)
{
const char *p = message;
while (*p && (*p != '\n' || p[1] != '\n'))
p++;
if (!*p)
add_to_msg(sha1_to_hex(commit->object.sha1));
p += 2;
add_to_msg(p);
return;
}
static void set_author_ident_env(const char *message)
{
const char *p = message;
if (!p)
die ("Could not read commit message of %s",
sha1_to_hex(commit->object.sha1));
while (*p && *p != '\n') {
const char *eol;
for (eol = p; *eol && *eol != '\n'; eol++)
; /* do nothing */
if (!prefixcmp(p, "author ")) {
char *line, *pend, *email, *timestamp;
p += 7;
line = xmalloc(eol + 1 - p);
memcpy(line, p, eol - p);
line[eol - p] = '\0';
email = strchr(line, '<');
if (!email)
die ("Could not extract author email from %s",
sha1_to_hex(commit->object.sha1));
if (email == line)
pend = line;
else
for (pend = email; pend != line + 1 &&
isspace(pend[-1]); pend--);
; /* do nothing */
*pend = '\0';
email++;
timestamp = strchr(email, '>');
if (!timestamp)
die ("Could not extract author email from %s",
sha1_to_hex(commit->object.sha1));
*timestamp = '\0';
for (timestamp++; *timestamp && isspace(*timestamp);
timestamp++)
; /* do nothing */
setenv("GIT_AUTHOR_NAME", line, 1);
setenv("GIT_AUTHOR_EMAIL", email, 1);
setenv("GIT_AUTHOR_DATE", timestamp, 1);
free(line);
return;
}
p = eol;
if (*p == '\n')
p++;
}
die ("No author information found in %s",
sha1_to_hex(commit->object.sha1));
}
static int merge_recursive(const char *base_sha1,
const char *head_sha1, const char *head_name,
const char *next_sha1, const char *next_name)
{
char buffer[256];
const char *argv[6];
sprintf(buffer, "GITHEAD_%s", head_sha1);
setenv(buffer, head_name, 1);
sprintf(buffer, "GITHEAD_%s", next_sha1);
setenv(buffer, next_name, 1);
/*
* This three way merge is an interesting one. We are at
* $head, and would want to apply the change between $commit
* and $prev on top of us (when reverting), or the change between
* $prev and $commit on top of us (when cherry-picking or replaying).
*/
argv[0] = "merge-recursive";
argv[1] = base_sha1;
argv[2] = "--";
argv[3] = head_sha1;
argv[4] = next_sha1;
argv[5] = NULL;
return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
}
static int revert_or_cherry_pick(int argc, const char **argv)
{
unsigned char head[20];
struct commit *base, *next;
int i;
char *oneline, *reencoded_message = NULL;
const char *message, *encoding;
const char *defmsg = xstrdup(git_path("MERGE_MSG"));
git_config(git_default_config);
me = action == REVERT ? "revert" : "cherry-pick";
setenv(GIT_REFLOG_ACTION, me, 0);
parse_options(argc, argv);
/* this is copied from the shell script, but it's never triggered... */
if (action == REVERT && replay)
die("revert is incompatible with replay");
if (no_commit) {
/*
* We do not intend to commit immediately. We just want to
* merge the differences in.
*/
if (write_tree(head, 0, NULL))
die ("Your index file is unmerged.");
} else {
struct wt_status s;
if (get_sha1("HEAD", head))
die ("You do not have a valid HEAD");
wt_status_prepare(&s);
if (s.commitable || s.workdir_dirty)
die ("Dirty index: cannot %s", me);
discard_cache();
}
if (!commit->parents)
die ("Cannot %s a root commit", me);
if (commit->parents->next)
die ("Cannot %s a multi-parent commit.", me);
if (!(message = commit->buffer))
die ("Cannot get commit message for %s",
sha1_to_hex(commit->object.sha1));
/*
* "commit" is an existing commit. We would want to apply
* the difference it introduces since its first parent "prev"
* on top of the current HEAD if we are cherry-pick. Or the
* reverse of it if we are revert.
*/
msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
encoding = get_encoding(message);
if (!encoding)
encoding = "utf-8";
if (!git_commit_encoding)
git_commit_encoding = "utf-8";
if ((reencoded_message = reencode_string(message,
git_commit_encoding, encoding)))
message = reencoded_message;
oneline = get_oneline(message);
if (action == REVERT) {
char *oneline_body = strchr(oneline, ' ');
base = commit;
next = commit->parents->item;
add_to_msg("Revert \"");
add_to_msg(oneline_body + 1);
add_to_msg("\"\n\nThis reverts commit ");
add_to_msg(sha1_to_hex(commit->object.sha1));
add_to_msg(".\n");
} else {
base = commit->parents->item;
next = commit;
set_author_ident_env(message);
add_message_to_msg(message);
if (!replay) {
add_to_msg("(cherry picked from commit ");
add_to_msg(sha1_to_hex(commit->object.sha1));
add_to_msg(")\n");
}
}
if (needed_deref) {
add_to_msg("(original 'git ");
add_to_msg(me);
add_to_msg("' arguments: ");
for (i = 0; i < argc; i++) {
if (i)
add_to_msg(" ");
add_to_msg(argv[i]);
}
add_to_msg(")\n");
}
if (merge_recursive(sha1_to_hex(base->object.sha1),
sha1_to_hex(head), "HEAD",
sha1_to_hex(next->object.sha1), oneline) ||
write_tree(head, 0, NULL)) {
add_to_msg("\nConflicts:\n\n");
read_cache();
for (i = 0; i < active_nr;) {
struct cache_entry *ce = active_cache[i++];
if (ce_stage(ce)) {
add_to_msg("\t");
add_to_msg(ce->name);
add_to_msg("\n");
while (i < active_nr && !strcmp(ce->name,
active_cache[i]->name))
i++;
}
}
if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
die ("Error wrapping up %s", defmsg);
fprintf(stderr, "Automatic %s failed. "
"After resolving the conflicts,\n"
"mark the corrected paths with 'git-add <paths>'\n"
"and commit the result.\n", me);
if (action == CHERRY_PICK) {
fprintf(stderr, "When commiting, use the option "
"'-c %s' to retain authorship and message.\n",
find_unique_abbrev(commit->object.sha1,
DEFAULT_ABBREV));
}
exit(1);
}
if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
die ("Error wrapping up %s", defmsg);
fprintf(stderr, "Finished one %s.\n", me);
/*
*
* If we are cherry-pick, and if the merge did not result in
* hand-editing, we will hit this commit and inherit the original
* author date and name.
* If we are revert, or if our cherry-pick results in a hand merge,
* we had better say that the current user is responsible for that.
*/
if (!no_commit) {
if (edit)
return execl_git_cmd("commit", "-n", NULL);
else
return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
}
if (reencoded_message)
free(reencoded_message);
return 0;
}
int cmd_revert(int argc, const char **argv, const char *prefix)
{
if (isatty(0))
edit = 1;
action = REVERT;
return revert_or_cherry_pick(argc, argv);
}
int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
{
replay = 1;
action = CHERRY_PICK;
return revert_or_cherry_pick(argc, argv);
}