Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "builtin.h"
   3#include "object.h"
   4#include "commit.h"
   5#include "tag.h"
   6#include "wt-status.h"
   7#include "run-command.h"
   8#include "exec_cmd.h"
   9#include "utf8.h"
  10
  11/*
  12 * This implements the builtins revert and cherry-pick.
  13 *
  14 * Copyright (c) 2007 Johannes E. Schindelin
  15 *
  16 * Based on git-revert.sh, which is
  17 *
  18 * Copyright (c) 2005 Linus Torvalds
  19 * Copyright (c) 2005 Junio C Hamano
  20 */
  21
  22static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] <commit-ish>";
  23
  24static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";
  25
  26static int edit;
  27static int replay;
  28static enum { REVERT, CHERRY_PICK } action;
  29static int no_commit;
  30static struct commit *commit;
  31static int needed_deref;
  32
  33static const char *me;
  34
  35#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  36
  37static void parse_options(int argc, const char **argv)
  38{
  39        const char *usage_str = action == REVERT ?
  40                revert_usage : cherry_pick_usage;
  41        unsigned char sha1[20];
  42        const char *arg;
  43        int i;
  44
  45        if (argc < 2)
  46                usage(usage_str);
  47
  48        for (i = 1; i < argc; i++) {
  49                arg = argv[i];
  50                if (arg[0] != '-')
  51                        break;
  52                if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
  53                        no_commit = 1;
  54                else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
  55                        edit = 1;
  56                else if (!strcmp(arg, "--no-edit"))
  57                        edit = 0;
  58                else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
  59                                "to-expose-my-private-commit-object-name"))
  60                        replay = 0;
  61                else if (strcmp(arg, "-r"))
  62                        usage(usage_str);
  63        }
  64        if (i != argc - 1)
  65                usage(usage_str);
  66        arg = argv[argc - 1];
  67        if (get_sha1(arg, sha1))
  68                die ("Cannot find '%s'", arg);
  69        commit = (struct commit *)parse_object(sha1);
  70        if (!commit)
  71                die ("Could not find %s", sha1_to_hex(sha1));
  72        if (commit->object.type == OBJ_TAG) {
  73                commit = (struct commit *)
  74                        deref_tag((struct object *)commit, arg, strlen(arg));
  75                needed_deref = 1;
  76        }
  77        if (commit->object.type != OBJ_COMMIT)
  78                die ("'%s' does not point to a commit", arg);
  79}
  80
  81static char *get_oneline(const char *message)
  82{
  83        char *result;
  84        const char *p = message, *abbrev, *eol;
  85        int abbrev_len, oneline_len;
  86
  87        if (!p)
  88                die ("Could not read commit message of %s",
  89                                sha1_to_hex(commit->object.sha1));
  90        while (*p && (*p != '\n' || p[1] != '\n'))
  91                p++;
  92
  93        if (*p) {
  94                p += 2;
  95                for (eol = p + 1; *eol && *eol != '\n'; eol++)
  96                        ; /* do nothing */
  97        } else
  98                eol = p;
  99        abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 100        abbrev_len = strlen(abbrev);
 101        oneline_len = eol - p;
 102        result = xmalloc(abbrev_len + 5 + oneline_len);
 103        memcpy(result, abbrev, abbrev_len);
 104        memcpy(result + abbrev_len, "... ", 4);
 105        memcpy(result + abbrev_len + 4, p, oneline_len);
 106        result[abbrev_len + 4 + oneline_len] = '\0';
 107        return result;
 108}
 109
 110static char *get_encoding(const char *message)
 111{
 112        const char *p = message, *eol;
 113
 114        if (!p)
 115                die ("Could not read commit message of %s",
 116                                sha1_to_hex(commit->object.sha1));
 117        while (*p && *p != '\n') {
 118                for (eol = p + 1; *eol && *eol != '\n'; eol++)
 119                        ; /* do nothing */
 120                if (!prefixcmp(p, "encoding ")) {
 121                        char *result = xmalloc(eol - 8 - p);
 122                        strlcpy(result, p + 9, eol - 8 - p);
 123                        return result;
 124                }
 125                p = eol;
 126                if (*p == '\n')
 127                        p++;
 128        }
 129        return NULL;
 130}
 131
 132static struct lock_file msg_file;
 133static int msg_fd;
 134
 135static void add_to_msg(const char *string)
 136{
 137        int len = strlen(string);
 138        if (write_in_full(msg_fd, string, len) < 0)
 139                die ("Could not write to MERGE_MSG");
 140}
 141
 142static void add_message_to_msg(const char *message)
 143{
 144        const char *p = message;
 145        while (*p && (*p != '\n' || p[1] != '\n'))
 146                p++;
 147
 148        if (!*p)
 149                add_to_msg(sha1_to_hex(commit->object.sha1));
 150
 151        p += 2;
 152        add_to_msg(p);
 153        return;
 154}
 155
 156static void set_author_ident_env(const char *message)
 157{
 158        const char *p = message;
 159        if (!p)
 160                die ("Could not read commit message of %s",
 161                                sha1_to_hex(commit->object.sha1));
 162        while (*p && *p != '\n') {
 163                const char *eol;
 164
 165                for (eol = p; *eol && *eol != '\n'; eol++)
 166                        ; /* do nothing */
 167                if (!prefixcmp(p, "author ")) {
 168                        char *line, *pend, *email, *timestamp;
 169
 170                        p += 7;
 171                        line = xmemdupz(p, eol - p);
 172                        email = strchr(line, '<');
 173                        if (!email)
 174                                die ("Could not extract author email from %s",
 175                                        sha1_to_hex(commit->object.sha1));
 176                        if (email == line)
 177                                pend = line;
 178                        else
 179                                for (pend = email; pend != line + 1 &&
 180                                                isspace(pend[-1]); pend--);
 181                                        ; /* do nothing */
 182                        *pend = '\0';
 183                        email++;
 184                        timestamp = strchr(email, '>');
 185                        if (!timestamp)
 186                                die ("Could not extract author email from %s",
 187                                        sha1_to_hex(commit->object.sha1));
 188                        *timestamp = '\0';
 189                        for (timestamp++; *timestamp && isspace(*timestamp);
 190                                        timestamp++)
 191                                ; /* do nothing */
 192                        setenv("GIT_AUTHOR_NAME", line, 1);
 193                        setenv("GIT_AUTHOR_EMAIL", email, 1);
 194                        setenv("GIT_AUTHOR_DATE", timestamp, 1);
 195                        free(line);
 196                        return;
 197                }
 198                p = eol;
 199                if (*p == '\n')
 200                        p++;
 201        }
 202        die ("No author information found in %s",
 203                        sha1_to_hex(commit->object.sha1));
 204}
 205
 206static int merge_recursive(const char *base_sha1,
 207                const char *head_sha1, const char *head_name,
 208                const char *next_sha1, const char *next_name)
 209{
 210        char buffer[256];
 211        const char *argv[6];
 212
 213        sprintf(buffer, "GITHEAD_%s", head_sha1);
 214        setenv(buffer, head_name, 1);
 215        sprintf(buffer, "GITHEAD_%s", next_sha1);
 216        setenv(buffer, next_name, 1);
 217
 218        /*
 219         * This three way merge is an interesting one.  We are at
 220         * $head, and would want to apply the change between $commit
 221         * and $prev on top of us (when reverting), or the change between
 222         * $prev and $commit on top of us (when cherry-picking or replaying).
 223         */
 224        argv[0] = "merge-recursive";
 225        argv[1] = base_sha1;
 226        argv[2] = "--";
 227        argv[3] = head_sha1;
 228        argv[4] = next_sha1;
 229        argv[5] = NULL;
 230
 231        return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 232}
 233
 234static int revert_or_cherry_pick(int argc, const char **argv)
 235{
 236        unsigned char head[20];
 237        struct commit *base, *next;
 238        int i;
 239        char *oneline, *reencoded_message = NULL;
 240        const char *message, *encoding;
 241        const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 242
 243        git_config(git_default_config);
 244        me = action == REVERT ? "revert" : "cherry-pick";
 245        setenv(GIT_REFLOG_ACTION, me, 0);
 246        parse_options(argc, argv);
 247
 248        /* this is copied from the shell script, but it's never triggered... */
 249        if (action == REVERT && replay)
 250                die("revert is incompatible with replay");
 251
 252        if (no_commit) {
 253                /*
 254                 * We do not intend to commit immediately.  We just want to
 255                 * merge the differences in.
 256                 */
 257                if (write_tree(head, 0, NULL))
 258                        die ("Your index file is unmerged.");
 259        } else {
 260                struct wt_status s;
 261
 262                if (get_sha1("HEAD", head))
 263                        die ("You do not have a valid HEAD");
 264                wt_status_prepare(&s);
 265                if (s.commitable || s.workdir_dirty)
 266                        die ("Dirty index: cannot %s", me);
 267                discard_cache();
 268        }
 269
 270        if (!commit->parents)
 271                die ("Cannot %s a root commit", me);
 272        if (commit->parents->next)
 273                die ("Cannot %s a multi-parent commit.", me);
 274        if (!(message = commit->buffer))
 275                die ("Cannot get commit message for %s",
 276                                sha1_to_hex(commit->object.sha1));
 277
 278        /*
 279         * "commit" is an existing commit.  We would want to apply
 280         * the difference it introduces since its first parent "prev"
 281         * on top of the current HEAD if we are cherry-pick.  Or the
 282         * reverse of it if we are revert.
 283         */
 284
 285        msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 286
 287        encoding = get_encoding(message);
 288        if (!encoding)
 289                encoding = "utf-8";
 290        if (!git_commit_encoding)
 291                git_commit_encoding = "utf-8";
 292        if ((reencoded_message = reencode_string(message,
 293                                        git_commit_encoding, encoding)))
 294                message = reencoded_message;
 295
 296        oneline = get_oneline(message);
 297
 298        if (action == REVERT) {
 299                char *oneline_body = strchr(oneline, ' ');
 300
 301                base = commit;
 302                next = commit->parents->item;
 303                add_to_msg("Revert \"");
 304                add_to_msg(oneline_body + 1);
 305                add_to_msg("\"\n\nThis reverts commit ");
 306                add_to_msg(sha1_to_hex(commit->object.sha1));
 307                add_to_msg(".\n");
 308        } else {
 309                base = commit->parents->item;
 310                next = commit;
 311                set_author_ident_env(message);
 312                add_message_to_msg(message);
 313                if (!replay) {
 314                        add_to_msg("(cherry picked from commit ");
 315                        add_to_msg(sha1_to_hex(commit->object.sha1));
 316                        add_to_msg(")\n");
 317                }
 318        }
 319        if (needed_deref) {
 320                add_to_msg("(original 'git ");
 321                add_to_msg(me);
 322                add_to_msg("' arguments: ");
 323                for (i = 0; i < argc; i++) {
 324                        if (i)
 325                                add_to_msg(" ");
 326                        add_to_msg(argv[i]);
 327                }
 328                add_to_msg(")\n");
 329        }
 330
 331        if (merge_recursive(sha1_to_hex(base->object.sha1),
 332                                sha1_to_hex(head), "HEAD",
 333                                sha1_to_hex(next->object.sha1), oneline) ||
 334                        write_tree(head, 0, NULL)) {
 335                add_to_msg("\nConflicts:\n\n");
 336                read_cache();
 337                for (i = 0; i < active_nr;) {
 338                        struct cache_entry *ce = active_cache[i++];
 339                        if (ce_stage(ce)) {
 340                                add_to_msg("\t");
 341                                add_to_msg(ce->name);
 342                                add_to_msg("\n");
 343                                while (i < active_nr && !strcmp(ce->name,
 344                                                active_cache[i]->name))
 345                                        i++;
 346                        }
 347                }
 348                if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 349                        die ("Error wrapping up %s", defmsg);
 350                fprintf(stderr, "Automatic %s failed.  "
 351                        "After resolving the conflicts,\n"
 352                        "mark the corrected paths with 'git-add <paths>'\n"
 353                        "and commit the result.\n", me);
 354                if (action == CHERRY_PICK) {
 355                        fprintf(stderr, "When commiting, use the option "
 356                                "'-c %s' to retain authorship and message.\n",
 357                                find_unique_abbrev(commit->object.sha1,
 358                                        DEFAULT_ABBREV));
 359                }
 360                exit(1);
 361        }
 362        if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 363                die ("Error wrapping up %s", defmsg);
 364        fprintf(stderr, "Finished one %s.\n", me);
 365
 366        /*
 367         *
 368         * If we are cherry-pick, and if the merge did not result in
 369         * hand-editing, we will hit this commit and inherit the original
 370         * author date and name.
 371         * If we are revert, or if our cherry-pick results in a hand merge,
 372         * we had better say that the current user is responsible for that.
 373         */
 374
 375        if (!no_commit) {
 376                if (edit)
 377                        return execl_git_cmd("commit", "-n", NULL);
 378                else
 379                        return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 380        }
 381        if (reencoded_message)
 382                free(reencoded_message);
 383
 384        return 0;
 385}
 386
 387int cmd_revert(int argc, const char **argv, const char *prefix)
 388{
 389        if (isatty(0))
 390                edit = 1;
 391        action = REVERT;
 392        return revert_or_cherry_pick(argc, argv);
 393}
 394
 395int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 396{
 397        replay = 1;
 398        action = CHERRY_PICK;
 399        return revert_or_cherry_pick(argc, argv);
 400}