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 = xmalloc(eol + 1 - p);
 172                        memcpy(line, p, eol - p);
 173                        line[eol - p] = '\0';
 174                        email = strchr(line, '<');
 175                        if (!email)
 176                                die ("Could not extract author email from %s",
 177                                        sha1_to_hex(commit->object.sha1));
 178                        if (email == line)
 179                                pend = line;
 180                        else
 181                                for (pend = email; pend != line + 1 &&
 182                                                isspace(pend[-1]); pend--);
 183                                        ; /* do nothing */
 184                        *pend = '\0';
 185                        email++;
 186                        timestamp = strchr(email, '>');
 187                        if (!timestamp)
 188                                die ("Could not extract author email from %s",
 189                                        sha1_to_hex(commit->object.sha1));
 190                        *timestamp = '\0';
 191                        for (timestamp++; *timestamp && isspace(*timestamp);
 192                                        timestamp++)
 193                                ; /* do nothing */
 194                        setenv("GIT_AUTHOR_NAME", line, 1);
 195                        setenv("GIT_AUTHOR_EMAIL", email, 1);
 196                        setenv("GIT_AUTHOR_DATE", timestamp, 1);
 197                        free(line);
 198                        return;
 199                }
 200                p = eol;
 201                if (*p == '\n')
 202                        p++;
 203        }
 204        die ("No author information found in %s",
 205                        sha1_to_hex(commit->object.sha1));
 206}
 207
 208static int merge_recursive(const char *base_sha1,
 209                const char *head_sha1, const char *head_name,
 210                const char *next_sha1, const char *next_name)
 211{
 212        char buffer[256];
 213        const char *argv[6];
 214
 215        sprintf(buffer, "GITHEAD_%s", head_sha1);
 216        setenv(buffer, head_name, 1);
 217        sprintf(buffer, "GITHEAD_%s", next_sha1);
 218        setenv(buffer, next_name, 1);
 219
 220        /*
 221         * This three way merge is an interesting one.  We are at
 222         * $head, and would want to apply the change between $commit
 223         * and $prev on top of us (when reverting), or the change between
 224         * $prev and $commit on top of us (when cherry-picking or replaying).
 225         */
 226        argv[0] = "merge-recursive";
 227        argv[1] = base_sha1;
 228        argv[2] = "--";
 229        argv[3] = head_sha1;
 230        argv[4] = next_sha1;
 231        argv[5] = NULL;
 232
 233        return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
 234}
 235
 236static int revert_or_cherry_pick(int argc, const char **argv)
 237{
 238        unsigned char head[20];
 239        struct commit *base, *next;
 240        int i;
 241        char *oneline, *reencoded_message = NULL;
 242        const char *message, *encoding;
 243        const char *defmsg = xstrdup(git_path("MERGE_MSG"));
 244
 245        git_config(git_default_config);
 246        me = action == REVERT ? "revert" : "cherry-pick";
 247        setenv(GIT_REFLOG_ACTION, me, 0);
 248        parse_options(argc, argv);
 249
 250        /* this is copied from the shell script, but it's never triggered... */
 251        if (action == REVERT && replay)
 252                die("revert is incompatible with replay");
 253
 254        if (no_commit) {
 255                /*
 256                 * We do not intend to commit immediately.  We just want to
 257                 * merge the differences in.
 258                 */
 259                if (write_tree(head, 0, NULL))
 260                        die ("Your index file is unmerged.");
 261        } else {
 262                struct wt_status s;
 263
 264                if (get_sha1("HEAD", head))
 265                        die ("You do not have a valid HEAD");
 266                wt_status_prepare(&s);
 267                if (s.commitable || s.workdir_dirty)
 268                        die ("Dirty index: cannot %s", me);
 269                discard_cache();
 270        }
 271
 272        if (!commit->parents)
 273                die ("Cannot %s a root commit", me);
 274        if (commit->parents->next)
 275                die ("Cannot %s a multi-parent commit.", me);
 276        if (!(message = commit->buffer))
 277                die ("Cannot get commit message for %s",
 278                                sha1_to_hex(commit->object.sha1));
 279
 280        /*
 281         * "commit" is an existing commit.  We would want to apply
 282         * the difference it introduces since its first parent "prev"
 283         * on top of the current HEAD if we are cherry-pick.  Or the
 284         * reverse of it if we are revert.
 285         */
 286
 287        msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
 288
 289        encoding = get_encoding(message);
 290        if (!encoding)
 291                encoding = "utf-8";
 292        if (!git_commit_encoding)
 293                git_commit_encoding = "utf-8";
 294        if ((reencoded_message = reencode_string(message,
 295                                        git_commit_encoding, encoding)))
 296                message = reencoded_message;
 297
 298        oneline = get_oneline(message);
 299
 300        if (action == REVERT) {
 301                char *oneline_body = strchr(oneline, ' ');
 302
 303                base = commit;
 304                next = commit->parents->item;
 305                add_to_msg("Revert \"");
 306                add_to_msg(oneline_body + 1);
 307                add_to_msg("\"\n\nThis reverts commit ");
 308                add_to_msg(sha1_to_hex(commit->object.sha1));
 309                add_to_msg(".\n");
 310        } else {
 311                base = commit->parents->item;
 312                next = commit;
 313                set_author_ident_env(message);
 314                add_message_to_msg(message);
 315                if (!replay) {
 316                        add_to_msg("(cherry picked from commit ");
 317                        add_to_msg(sha1_to_hex(commit->object.sha1));
 318                        add_to_msg(")\n");
 319                }
 320        }
 321        if (needed_deref) {
 322                add_to_msg("(original 'git ");
 323                add_to_msg(me);
 324                add_to_msg("' arguments: ");
 325                for (i = 0; i < argc; i++) {
 326                        if (i)
 327                                add_to_msg(" ");
 328                        add_to_msg(argv[i]);
 329                }
 330                add_to_msg(")\n");
 331        }
 332
 333        if (merge_recursive(sha1_to_hex(base->object.sha1),
 334                                sha1_to_hex(head), "HEAD",
 335                                sha1_to_hex(next->object.sha1), oneline) ||
 336                        write_tree(head, 0, NULL)) {
 337                add_to_msg("\nConflicts:\n\n");
 338                read_cache();
 339                for (i = 0; i < active_nr;) {
 340                        struct cache_entry *ce = active_cache[i++];
 341                        if (ce_stage(ce)) {
 342                                add_to_msg("\t");
 343                                add_to_msg(ce->name);
 344                                add_to_msg("\n");
 345                                while (i < active_nr && !strcmp(ce->name,
 346                                                active_cache[i]->name))
 347                                        i++;
 348                        }
 349                }
 350                if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 351                        die ("Error wrapping up %s", defmsg);
 352                fprintf(stderr, "Automatic %s failed.  "
 353                        "After resolving the conflicts,\n"
 354                        "mark the corrected paths with 'git-add <paths>'\n"
 355                        "and commit the result.\n", me);
 356                if (action == CHERRY_PICK) {
 357                        fprintf(stderr, "When commiting, use the option "
 358                                "'-c %s' to retain authorship and message.\n",
 359                                find_unique_abbrev(commit->object.sha1,
 360                                        DEFAULT_ABBREV));
 361                }
 362                exit(1);
 363        }
 364        if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
 365                die ("Error wrapping up %s", defmsg);
 366        fprintf(stderr, "Finished one %s.\n", me);
 367
 368        /*
 369         *
 370         * If we are cherry-pick, and if the merge did not result in
 371         * hand-editing, we will hit this commit and inherit the original
 372         * author date and name.
 373         * If we are revert, or if our cherry-pick results in a hand merge,
 374         * we had better say that the current user is responsible for that.
 375         */
 376
 377        if (!no_commit) {
 378                if (edit)
 379                        return execl_git_cmd("commit", "-n", NULL);
 380                else
 381                        return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
 382        }
 383        if (reencoded_message)
 384                free(reencoded_message);
 385
 386        return 0;
 387}
 388
 389int cmd_revert(int argc, const char **argv, const char *prefix)
 390{
 391        if (isatty(0))
 392                edit = 1;
 393        action = REVERT;
 394        return revert_or_cherry_pick(argc, argv);
 395}
 396
 397int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 398{
 399        replay = 1;
 400        action = CHERRY_PICK;
 401        return revert_or_cherry_pick(argc, argv);
 402}