Andrew's git / gitweb.git / commit.c
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commit.con commit Remove unnecessary git-rm --cached reference from status output (3368d11)
   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "pkt-line.h"
   5#include "utf8.h"
   6
   7int save_commit_buffer = 1;
   8
   9struct sort_node
  10{
  11        /*
  12         * the number of children of the associated commit
  13         * that also occur in the list being sorted.
  14         */
  15        unsigned int indegree;
  16
  17        /*
  18         * reference to original list item that we will re-use
  19         * on output.
  20         */
  21        struct commit_list * list_item;
  22
  23};
  24
  25const char *commit_type = "commit";
  26
  27struct cmt_fmt_map {
  28        const char *n;
  29        size_t cmp_len;
  30        enum cmit_fmt v;
  31} cmt_fmts[] = {
  32        { "raw",        1,      CMIT_FMT_RAW },
  33        { "medium",     1,      CMIT_FMT_MEDIUM },
  34        { "short",      1,      CMIT_FMT_SHORT },
  35        { "email",      1,      CMIT_FMT_EMAIL },
  36        { "full",       5,      CMIT_FMT_FULL },
  37        { "fuller",     5,      CMIT_FMT_FULLER },
  38        { "oneline",    1,      CMIT_FMT_ONELINE },
  39};
  40
  41enum cmit_fmt get_commit_format(const char *arg)
  42{
  43        int i;
  44
  45        if (!arg || !*arg)
  46                return CMIT_FMT_DEFAULT;
  47        if (*arg == '=')
  48                arg++;
  49        for (i = 0; i < ARRAY_SIZE(cmt_fmts); i++) {
  50                if (!strncmp(arg, cmt_fmts[i].n, cmt_fmts[i].cmp_len))
  51                        return cmt_fmts[i].v;
  52        }
  53
  54        die("invalid --pretty format: %s", arg);
  55}
  56
  57static struct commit *check_commit(struct object *obj,
  58                                   const unsigned char *sha1,
  59                                   int quiet)
  60{
  61        if (obj->type != OBJ_COMMIT) {
  62                if (!quiet)
  63                        error("Object %s is a %s, not a commit",
  64                              sha1_to_hex(sha1), typename(obj->type));
  65                return NULL;
  66        }
  67        return (struct commit *) obj;
  68}
  69
  70struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  71                                              int quiet)
  72{
  73        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  74
  75        if (!obj)
  76                return NULL;
  77        return check_commit(obj, sha1, quiet);
  78}
  79
  80struct commit *lookup_commit_reference(const unsigned char *sha1)
  81{
  82        return lookup_commit_reference_gently(sha1, 0);
  83}
  84
  85struct commit *lookup_commit(const unsigned char *sha1)
  86{
  87        struct object *obj = lookup_object(sha1);
  88        if (!obj) {
  89                struct commit *ret = alloc_commit_node();
  90                created_object(sha1, &ret->object);
  91                ret->object.type = OBJ_COMMIT;
  92                return ret;
  93        }
  94        if (!obj->type)
  95                obj->type = OBJ_COMMIT;
  96        return check_commit(obj, sha1, 0);
  97}
  98
  99static unsigned long parse_commit_date(const char *buf)
 100{
 101        unsigned long date;
 102
 103        if (memcmp(buf, "author", 6))
 104                return 0;
 105        while (*buf++ != '\n')
 106                /* nada */;
 107        if (memcmp(buf, "committer", 9))
 108                return 0;
 109        while (*buf++ != '>')
 110                /* nada */;
 111        date = strtoul(buf, NULL, 10);
 112        if (date == ULONG_MAX)
 113                date = 0;
 114        return date;
 115}
 116
 117static struct commit_graft **commit_graft;
 118static int commit_graft_alloc, commit_graft_nr;
 119
 120static int commit_graft_pos(const unsigned char *sha1)
 121{
 122        int lo, hi;
 123        lo = 0;
 124        hi = commit_graft_nr;
 125        while (lo < hi) {
 126                int mi = (lo + hi) / 2;
 127                struct commit_graft *graft = commit_graft[mi];
 128                int cmp = hashcmp(sha1, graft->sha1);
 129                if (!cmp)
 130                        return mi;
 131                if (cmp < 0)
 132                        hi = mi;
 133                else
 134                        lo = mi + 1;
 135        }
 136        return -lo - 1;
 137}
 138
 139int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 140{
 141        int pos = commit_graft_pos(graft->sha1);
 142        
 143        if (0 <= pos) {
 144                if (ignore_dups)
 145                        free(graft);
 146                else {
 147                        free(commit_graft[pos]);
 148                        commit_graft[pos] = graft;
 149                }
 150                return 1;
 151        }
 152        pos = -pos - 1;
 153        if (commit_graft_alloc <= ++commit_graft_nr) {
 154                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 155                commit_graft = xrealloc(commit_graft,
 156                                        sizeof(*commit_graft) *
 157                                        commit_graft_alloc);
 158        }
 159        if (pos < commit_graft_nr)
 160                memmove(commit_graft + pos + 1,
 161                        commit_graft + pos,
 162                        (commit_graft_nr - pos - 1) *
 163                        sizeof(*commit_graft));
 164        commit_graft[pos] = graft;
 165        return 0;
 166}
 167
 168struct commit_graft *read_graft_line(char *buf, int len)
 169{
 170        /* The format is just "Commit Parent1 Parent2 ...\n" */
 171        int i;
 172        struct commit_graft *graft = NULL;
 173
 174        if (buf[len-1] == '\n')
 175                buf[--len] = 0;
 176        if (buf[0] == '#' || buf[0] == '\0')
 177                return NULL;
 178        if ((len + 1) % 41) {
 179        bad_graft_data:
 180                error("bad graft data: %s", buf);
 181                free(graft);
 182                return NULL;
 183        }
 184        i = (len + 1) / 41 - 1;
 185        graft = xmalloc(sizeof(*graft) + 20 * i);
 186        graft->nr_parent = i;
 187        if (get_sha1_hex(buf, graft->sha1))
 188                goto bad_graft_data;
 189        for (i = 40; i < len; i += 41) {
 190                if (buf[i] != ' ')
 191                        goto bad_graft_data;
 192                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 193                        goto bad_graft_data;
 194        }
 195        return graft;
 196}
 197
 198int read_graft_file(const char *graft_file)
 199{
 200        FILE *fp = fopen(graft_file, "r");
 201        char buf[1024];
 202        if (!fp)
 203                return -1;
 204        while (fgets(buf, sizeof(buf), fp)) {
 205                /* The format is just "Commit Parent1 Parent2 ...\n" */
 206                int len = strlen(buf);
 207                struct commit_graft *graft = read_graft_line(buf, len);
 208                if (!graft)
 209                        continue;
 210                if (register_commit_graft(graft, 1))
 211                        error("duplicate graft data: %s", buf);
 212        }
 213        fclose(fp);
 214        return 0;
 215}
 216
 217static void prepare_commit_graft(void)
 218{
 219        static int commit_graft_prepared;
 220        char *graft_file;
 221
 222        if (commit_graft_prepared)
 223                return;
 224        graft_file = get_graft_file();
 225        read_graft_file(graft_file);
 226        /* make sure shallows are read */
 227        is_repository_shallow();
 228        commit_graft_prepared = 1;
 229}
 230
 231static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 232{
 233        int pos;
 234        prepare_commit_graft();
 235        pos = commit_graft_pos(sha1);
 236        if (pos < 0)
 237                return NULL;
 238        return commit_graft[pos];
 239}
 240
 241int write_shallow_commits(int fd, int use_pack_protocol)
 242{
 243        int i, count = 0;
 244        for (i = 0; i < commit_graft_nr; i++)
 245                if (commit_graft[i]->nr_parent < 0) {
 246                        const char *hex =
 247                                sha1_to_hex(commit_graft[i]->sha1);
 248                        count++;
 249                        if (use_pack_protocol)
 250                                packet_write(fd, "shallow %s", hex);
 251                        else {
 252                                write(fd, hex,  40);
 253                                write(fd, "\n", 1);
 254                        }
 255                }
 256        return count;
 257}
 258
 259int unregister_shallow(const unsigned char *sha1)
 260{
 261        int pos = commit_graft_pos(sha1);
 262        if (pos < 0)
 263                return -1;
 264        if (pos + 1 < commit_graft_nr)
 265                memcpy(commit_graft + pos, commit_graft + pos + 1,
 266                                sizeof(struct commit_graft *)
 267                                * (commit_graft_nr - pos - 1));
 268        commit_graft_nr--;
 269        return 0;
 270}
 271
 272int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 273{
 274        char *tail = buffer;
 275        char *bufptr = buffer;
 276        unsigned char parent[20];
 277        struct commit_list **pptr;
 278        struct commit_graft *graft;
 279        unsigned n_refs = 0;
 280
 281        if (item->object.parsed)
 282                return 0;
 283        item->object.parsed = 1;
 284        tail += size;
 285        if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 286                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 287        if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 288                return error("bad tree pointer in commit %s",
 289                             sha1_to_hex(item->object.sha1));
 290        item->tree = lookup_tree(parent);
 291        if (item->tree)
 292                n_refs++;
 293        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 294        pptr = &item->parents;
 295
 296        graft = lookup_commit_graft(item->object.sha1);
 297        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 298                struct commit *new_parent;
 299
 300                if (tail <= bufptr + 48 ||
 301                    get_sha1_hex(bufptr + 7, parent) ||
 302                    bufptr[47] != '\n')
 303                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 304                bufptr += 48;
 305                if (graft)
 306                        continue;
 307                new_parent = lookup_commit(parent);
 308                if (new_parent) {
 309                        pptr = &commit_list_insert(new_parent, pptr)->next;
 310                        n_refs++;
 311                }
 312        }
 313        if (graft) {
 314                int i;
 315                struct commit *new_parent;
 316                for (i = 0; i < graft->nr_parent; i++) {
 317                        new_parent = lookup_commit(graft->parent[i]);
 318                        if (!new_parent)
 319                                continue;
 320                        pptr = &commit_list_insert(new_parent, pptr)->next;
 321                        n_refs++;
 322                }
 323        }
 324        item->date = parse_commit_date(bufptr);
 325
 326        if (track_object_refs) {
 327                unsigned i = 0;
 328                struct commit_list *p;
 329                struct object_refs *refs = alloc_object_refs(n_refs);
 330                if (item->tree)
 331                        refs->ref[i++] = &item->tree->object;
 332                for (p = item->parents; p; p = p->next)
 333                        refs->ref[i++] = &p->item->object;
 334                set_object_refs(&item->object, refs);
 335        }
 336
 337        return 0;
 338}
 339
 340int parse_commit(struct commit *item)
 341{
 342        char type[20];
 343        void *buffer;
 344        unsigned long size;
 345        int ret;
 346
 347        if (item->object.parsed)
 348                return 0;
 349        buffer = read_sha1_file(item->object.sha1, type, &size);
 350        if (!buffer)
 351                return error("Could not read %s",
 352                             sha1_to_hex(item->object.sha1));
 353        if (strcmp(type, commit_type)) {
 354                free(buffer);
 355                return error("Object %s not a commit",
 356                             sha1_to_hex(item->object.sha1));
 357        }
 358        ret = parse_commit_buffer(item, buffer, size);
 359        if (save_commit_buffer && !ret) {
 360                item->buffer = buffer;
 361                return 0;
 362        }
 363        free(buffer);
 364        return ret;
 365}
 366
 367struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 368{
 369        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 370        new_list->item = item;
 371        new_list->next = *list_p;
 372        *list_p = new_list;
 373        return new_list;
 374}
 375
 376void free_commit_list(struct commit_list *list)
 377{
 378        while (list) {
 379                struct commit_list *temp = list;
 380                list = temp->next;
 381                free(temp);
 382        }
 383}
 384
 385struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 386{
 387        struct commit_list **pp = list;
 388        struct commit_list *p;
 389        while ((p = *pp) != NULL) {
 390                if (p->item->date < item->date) {
 391                        break;
 392                }
 393                pp = &p->next;
 394        }
 395        return commit_list_insert(item, pp);
 396}
 397
 398        
 399void sort_by_date(struct commit_list **list)
 400{
 401        struct commit_list *ret = NULL;
 402        while (*list) {
 403                insert_by_date((*list)->item, &ret);
 404                *list = (*list)->next;
 405        }
 406        *list = ret;
 407}
 408
 409struct commit *pop_most_recent_commit(struct commit_list **list,
 410                                      unsigned int mark)
 411{
 412        struct commit *ret = (*list)->item;
 413        struct commit_list *parents = ret->parents;
 414        struct commit_list *old = *list;
 415
 416        *list = (*list)->next;
 417        free(old);
 418
 419        while (parents) {
 420                struct commit *commit = parents->item;
 421                parse_commit(commit);
 422                if (!(commit->object.flags & mark)) {
 423                        commit->object.flags |= mark;
 424                        insert_by_date(commit, list);
 425                }
 426                parents = parents->next;
 427        }
 428        return ret;
 429}
 430
 431void clear_commit_marks(struct commit *commit, unsigned int mark)
 432{
 433        struct commit_list *parents;
 434
 435        commit->object.flags &= ~mark;
 436        parents = commit->parents;
 437        while (parents) {
 438                struct commit *parent = parents->item;
 439
 440                /* Have we already cleared this? */
 441                if (mark & parent->object.flags)
 442                        clear_commit_marks(parent, mark);
 443                parents = parents->next;
 444        }
 445}
 446
 447/*
 448 * Generic support for pretty-printing the header
 449 */
 450static int get_one_line(const char *msg, unsigned long len)
 451{
 452        int ret = 0;
 453
 454        while (len--) {
 455                char c = *msg++;
 456                if (!c)
 457                        break;
 458                ret++;
 459                if (c == '\n')
 460                        break;
 461        }
 462        return ret;
 463}
 464
 465static int is_rfc2047_special(char ch)
 466{
 467        return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
 468}
 469
 470static int add_rfc2047(char *buf, const char *line, int len)
 471{
 472        char *bp = buf;
 473        int i, needquote;
 474        static const char q_utf8[] = "=?utf-8?q?";
 475
 476        for (i = needquote = 0; !needquote && i < len; i++) {
 477                unsigned ch = line[i];
 478                if (ch & 0x80)
 479                        needquote++;
 480                if ((i + 1 < len) &&
 481                    (ch == '=' && line[i+1] == '?'))
 482                        needquote++;
 483        }
 484        if (!needquote)
 485                return sprintf(buf, "%.*s", len, line);
 486
 487        memcpy(bp, q_utf8, sizeof(q_utf8)-1);
 488        bp += sizeof(q_utf8)-1;
 489        for (i = 0; i < len; i++) {
 490                unsigned ch = line[i] & 0xFF;
 491                if (is_rfc2047_special(ch)) {
 492                        sprintf(bp, "=%02X", ch);
 493                        bp += 3;
 494                }
 495                else if (ch == ' ')
 496                        *bp++ = '_';
 497                else
 498                        *bp++ = ch;
 499        }
 500        memcpy(bp, "?=", 2);
 501        bp += 2;
 502        return bp - buf;
 503}
 504
 505static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf,
 506                         const char *line, int relative_date)
 507{
 508        char *date;
 509        int namelen;
 510        unsigned long time;
 511        int tz, ret;
 512        const char *filler = "    ";
 513
 514        if (fmt == CMIT_FMT_ONELINE)
 515                return 0;
 516        date = strchr(line, '>');
 517        if (!date)
 518                return 0;
 519        namelen = ++date - line;
 520        time = strtoul(date, &date, 10);
 521        tz = strtol(date, NULL, 10);
 522
 523        if (fmt == CMIT_FMT_EMAIL) {
 524                char *name_tail = strchr(line, '<');
 525                int display_name_length;
 526                if (!name_tail)
 527                        return 0;
 528                while (line < name_tail && isspace(name_tail[-1]))
 529                        name_tail--;
 530                display_name_length = name_tail - line;
 531                filler = "";
 532                strcpy(buf, "From: ");
 533                ret = strlen(buf);
 534                ret += add_rfc2047(buf + ret, line, display_name_length);
 535                memcpy(buf + ret, name_tail, namelen - display_name_length);
 536                ret += namelen - display_name_length;
 537                buf[ret++] = '\n';
 538        }
 539        else {
 540                ret = sprintf(buf, "%s: %.*s%.*s\n", what,
 541                              (fmt == CMIT_FMT_FULLER) ? 4 : 0,
 542                              filler, namelen, line);
 543        }
 544        switch (fmt) {
 545        case CMIT_FMT_MEDIUM:
 546                ret += sprintf(buf + ret, "Date:   %s\n",
 547                               show_date(time, tz, relative_date));
 548                break;
 549        case CMIT_FMT_EMAIL:
 550                ret += sprintf(buf + ret, "Date: %s\n",
 551                               show_rfc2822_date(time, tz));
 552                break;
 553        case CMIT_FMT_FULLER:
 554                ret += sprintf(buf + ret, "%sDate: %s\n", what,
 555                               show_date(time, tz, relative_date));
 556                break;
 557        default:
 558                /* notin' */
 559                break;
 560        }
 561        return ret;
 562}
 563
 564static int is_empty_line(const char *line, int *len_p)
 565{
 566        int len = *len_p;
 567        while (len && isspace(line[len-1]))
 568                len--;
 569        *len_p = len;
 570        return !len;
 571}
 572
 573static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 574{
 575        struct commit_list *parent = commit->parents;
 576        int offset;
 577
 578        if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
 579            !parent || !parent->next)
 580                return 0;
 581
 582        offset = sprintf(buf, "Merge:");
 583
 584        while (parent) {
 585                struct commit *p = parent->item;
 586                const char *hex = NULL;
 587                const char *dots;
 588                if (abbrev)
 589                        hex = find_unique_abbrev(p->object.sha1, abbrev);
 590                if (!hex)
 591                        hex = sha1_to_hex(p->object.sha1);
 592                dots = (abbrev && strlen(hex) != 40) ?  "..." : "";
 593                parent = parent->next;
 594
 595                offset += sprintf(buf + offset, " %s%s", hex, dots);
 596        }
 597        buf[offset++] = '\n';
 598        return offset;
 599}
 600
 601static char *get_header(const struct commit *commit, const char *key)
 602{
 603        int key_len = strlen(key);
 604        const char *line = commit->buffer;
 605
 606        for (;;) {
 607                const char *eol = strchr(line, '\n'), *next;
 608
 609                if (line == eol)
 610                        return NULL;
 611                if (!eol) {
 612                        eol = line + strlen(line);
 613                        next = NULL;
 614                } else
 615                        next = eol + 1;
 616                if (!strncmp(line, key, key_len) && line[key_len] == ' ') {
 617                        int len = eol - line - key_len;
 618                        char *ret = xmalloc(len);
 619                        memcpy(ret, line + key_len + 1, len - 1);
 620                        ret[len - 1] = '\0';
 621                        return ret;
 622                }
 623                line = next;
 624        }
 625}
 626
 627static char *replace_encoding_header(char *buf, char *encoding)
 628{
 629        char *encoding_header = strstr(buf, "\nencoding ");
 630        char *end_of_encoding_header;
 631        int encoding_header_pos;
 632        int encoding_header_len;
 633        int new_len;
 634        int need_len;
 635        int buflen = strlen(buf) + 1;
 636
 637        if (!encoding_header)
 638                return buf; /* should not happen but be defensive */
 639        encoding_header++;
 640        end_of_encoding_header = strchr(encoding_header, '\n');
 641        if (!end_of_encoding_header)
 642                return buf; /* should not happen but be defensive */
 643        end_of_encoding_header++;
 644
 645        encoding_header_len = end_of_encoding_header - encoding_header;
 646        encoding_header_pos = encoding_header - buf;
 647
 648        if (is_encoding_utf8(encoding)) {
 649                /* we have re-coded to UTF-8; drop the header */
 650                memmove(encoding_header, end_of_encoding_header,
 651                        buflen - (encoding_header_pos + encoding_header_len));
 652                return buf;
 653        }
 654        new_len = strlen(encoding);
 655        need_len = new_len + strlen("encoding \n");
 656        if (encoding_header_len < need_len) {
 657                buf = xrealloc(buf, buflen + (need_len - encoding_header_len));
 658                encoding_header = buf + encoding_header_pos;
 659                end_of_encoding_header = encoding_header + encoding_header_len;
 660        }
 661        memmove(end_of_encoding_header + (need_len - encoding_header_len),
 662                end_of_encoding_header,
 663                buflen - (encoding_header_pos + encoding_header_len));
 664        memcpy(encoding_header + 9, encoding, strlen(encoding));
 665        encoding_header[9 + new_len] = '\n';
 666        return buf;
 667}
 668
 669static char *logmsg_reencode(const struct commit *commit)
 670{
 671        char *encoding;
 672        char *out;
 673        char *output_encoding = (git_log_output_encoding
 674                                 ? git_log_output_encoding
 675                                 : git_commit_encoding);
 676
 677        if (!output_encoding)
 678                output_encoding = "utf-8";
 679        else if (!*output_encoding)
 680                return NULL;
 681        encoding = get_header(commit, "encoding");
 682        if (!encoding)
 683                return NULL;
 684        if (!strcmp(encoding, output_encoding))
 685                out = strdup(commit->buffer);
 686        else
 687                out = reencode_string(commit->buffer,
 688                                      output_encoding, encoding);
 689        if (out)
 690                out = replace_encoding_header(out, output_encoding);
 691
 692        free(encoding);
 693        if (!out)
 694                return NULL;
 695        return out;
 696}
 697
 698unsigned long pretty_print_commit(enum cmit_fmt fmt,
 699                                  const struct commit *commit,
 700                                  unsigned long len,
 701                                  char *buf, unsigned long space,
 702                                  int abbrev, const char *subject,
 703                                  const char *after_subject,
 704                                  int relative_date)
 705{
 706        int hdr = 1, body = 0, seen_title = 0;
 707        unsigned long offset = 0;
 708        int indent = 4;
 709        int parents_shown = 0;
 710        const char *msg = commit->buffer;
 711        int plain_non_ascii = 0;
 712        char *reencoded = logmsg_reencode(commit);
 713
 714        if (reencoded)
 715                msg = reencoded;
 716
 717        if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
 718                indent = 0;
 719
 720        /* After-subject is used to pass in Content-Type: multipart
 721         * MIME header; in that case we do not have to do the
 722         * plaintext content type even if the commit message has
 723         * non 7-bit ASCII character.  Otherwise, check if we need
 724         * to say this is not a 7-bit ASCII.
 725         */
 726        if (fmt == CMIT_FMT_EMAIL && !after_subject) {
 727                int i, ch, in_body;
 728
 729                for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
 730                        if (!in_body) {
 731                                /* author could be non 7-bit ASCII but
 732                                 * the log may be so; skip over the
 733                                 * header part first.
 734                                 */
 735                                if (ch == '\n' &&
 736                                    i + 1 < len && msg[i+1] == '\n')
 737                                        in_body = 1;
 738                        }
 739                        else if (ch & 0x80) {
 740                                plain_non_ascii = 1;
 741                                break;
 742                        }
 743                }
 744        }
 745
 746        for (;;) {
 747                const char *line = msg;
 748                int linelen = get_one_line(msg, len);
 749
 750                if (!linelen)
 751                        break;
 752
 753                /*
 754                 * We want some slop for indentation and a possible
 755                 * final "...". Thus the "+ 20".
 756                 */
 757                if (offset + linelen + 20 > space) {
 758                        memcpy(buf + offset, "    ...\n", 8);
 759                        offset += 8;
 760                        break;
 761                }
 762
 763                msg += linelen;
 764                len -= linelen;
 765                if (hdr) {
 766                        if (linelen == 1) {
 767                                hdr = 0;
 768                                if ((fmt != CMIT_FMT_ONELINE) && !subject)
 769                                        buf[offset++] = '\n';
 770                                continue;
 771                        }
 772                        if (fmt == CMIT_FMT_RAW) {
 773                                memcpy(buf + offset, line, linelen);
 774                                offset += linelen;
 775                                continue;
 776                        }
 777                        if (!memcmp(line, "parent ", 7)) {
 778                                if (linelen != 48)
 779                                        die("bad parent line in commit");
 780                                continue;
 781                        }
 782
 783                        if (!parents_shown) {
 784                                offset += add_merge_info(fmt, buf + offset,
 785                                                         commit, abbrev);
 786                                parents_shown = 1;
 787                                continue;
 788                        }
 789                        /*
 790                         * MEDIUM == DEFAULT shows only author with dates.
 791                         * FULL shows both authors but not dates.
 792                         * FULLER shows both authors and dates.
 793                         */
 794                        if (!memcmp(line, "author ", 7))
 795                                offset += add_user_info("Author", fmt,
 796                                                        buf + offset,
 797                                                        line + 7,
 798                                                        relative_date);
 799                        if (!memcmp(line, "committer ", 10) &&
 800                            (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
 801                                offset += add_user_info("Commit", fmt,
 802                                                        buf + offset,
 803                                                        line + 10,
 804                                                        relative_date);
 805                        continue;
 806                }
 807
 808                if (!subject)
 809                        body = 1;
 810
 811                if (is_empty_line(line, &linelen)) {
 812                        if (!seen_title)
 813                                continue;
 814                        if (!body)
 815                                continue;
 816                        if (subject)
 817                                continue;
 818                        if (fmt == CMIT_FMT_SHORT)
 819                                break;
 820                }
 821
 822                seen_title = 1;
 823                if (subject) {
 824                        int slen = strlen(subject);
 825                        memcpy(buf + offset, subject, slen);
 826                        offset += slen;
 827                        offset += add_rfc2047(buf + offset, line, linelen);
 828                }
 829                else {
 830                        memset(buf + offset, ' ', indent);
 831                        memcpy(buf + offset + indent, line, linelen);
 832                        offset += linelen + indent;
 833                }
 834                buf[offset++] = '\n';
 835                if (fmt == CMIT_FMT_ONELINE)
 836                        break;
 837                if (subject && plain_non_ascii) {
 838                        static const char header[] =
 839                                "Content-Type: text/plain; charset=UTF-8\n"
 840                                "Content-Transfer-Encoding: 8bit\n";
 841                        memcpy(buf + offset, header, sizeof(header)-1);
 842                        offset += sizeof(header)-1;
 843                }
 844                if (after_subject) {
 845                        int slen = strlen(after_subject);
 846                        if (slen > space - offset - 1)
 847                                slen = space - offset - 1;
 848                        memcpy(buf + offset, after_subject, slen);
 849                        offset += slen;
 850                        after_subject = NULL;
 851                }
 852                subject = NULL;
 853        }
 854        while (offset && isspace(buf[offset-1]))
 855                offset--;
 856        /* Make sure there is an EOLN for the non-oneline case */
 857        if (fmt != CMIT_FMT_ONELINE)
 858                buf[offset++] = '\n';
 859        /*
 860         * make sure there is another EOLN to separate the headers from whatever
 861         * body the caller appends if we haven't already written a body
 862         */
 863        if (fmt == CMIT_FMT_EMAIL && !body)
 864                buf[offset++] = '\n';
 865        buf[offset] = '\0';
 866
 867        free(reencoded);
 868        return offset;
 869}
 870
 871struct commit *pop_commit(struct commit_list **stack)
 872{
 873        struct commit_list *top = *stack;
 874        struct commit *item = top ? top->item : NULL;
 875
 876        if (top) {
 877                *stack = top->next;
 878                free(top);
 879        }
 880        return item;
 881}
 882
 883int count_parents(struct commit * commit)
 884{
 885        int count;
 886        struct commit_list * parents = commit->parents;
 887        for (count = 0; parents; parents = parents->next,count++)
 888                ;
 889        return count;
 890}
 891
 892void topo_sort_default_setter(struct commit *c, void *data)
 893{
 894        c->util = data;
 895}
 896
 897void *topo_sort_default_getter(struct commit *c)
 898{
 899        return c->util;
 900}
 901
 902/*
 903 * Performs an in-place topological sort on the list supplied.
 904 */
 905void sort_in_topological_order(struct commit_list ** list, int lifo)
 906{
 907        sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 908                                     topo_sort_default_getter);
 909}
 910
 911void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 912                                  topo_sort_set_fn_t setter,
 913                                  topo_sort_get_fn_t getter)
 914{
 915        struct commit_list * next = *list;
 916        struct commit_list * work = NULL, **insert;
 917        struct commit_list ** pptr = list;
 918        struct sort_node * nodes;
 919        struct sort_node * next_nodes;
 920        int count = 0;
 921
 922        /* determine the size of the list */
 923        while (next) {
 924                next = next->next;
 925                count++;
 926        }
 927        
 928        if (!count)
 929                return;
 930        /* allocate an array to help sort the list */
 931        nodes = xcalloc(count, sizeof(*nodes));
 932        /* link the list to the array */
 933        next_nodes = nodes;
 934        next=*list;
 935        while (next) {
 936                next_nodes->list_item = next;
 937                setter(next->item, next_nodes);
 938                next_nodes++;
 939                next = next->next;
 940        }
 941        /* update the indegree */
 942        next=*list;
 943        while (next) {
 944                struct commit_list * parents = next->item->parents;
 945                while (parents) {
 946                        struct commit * parent=parents->item;
 947                        struct sort_node * pn = (struct sort_node *) getter(parent);
 948
 949                        if (pn)
 950                                pn->indegree++;
 951                        parents=parents->next;
 952                }
 953                next=next->next;
 954        }
 955        /* 
 956         * find the tips
 957         *
 958         * tips are nodes not reachable from any other node in the list 
 959         * 
 960         * the tips serve as a starting set for the work queue.
 961         */
 962        next=*list;
 963        insert = &work;
 964        while (next) {
 965                struct sort_node * node = (struct sort_node *) getter(next->item);
 966
 967                if (node->indegree == 0) {
 968                        insert = &commit_list_insert(next->item, insert)->next;
 969                }
 970                next=next->next;
 971        }
 972
 973        /* process the list in topological order */
 974        if (!lifo)
 975                sort_by_date(&work);
 976        while (work) {
 977                struct commit * work_item = pop_commit(&work);
 978                struct sort_node * work_node = (struct sort_node *) getter(work_item);
 979                struct commit_list * parents = work_item->parents;
 980
 981                while (parents) {
 982                        struct commit * parent=parents->item;
 983                        struct sort_node * pn = (struct sort_node *) getter(parent);
 984
 985                        if (pn) {
 986                                /*
 987                                 * parents are only enqueued for emission 
 988                                 * when all their children have been emitted thereby
 989                                 * guaranteeing topological order.
 990                                 */
 991                                pn->indegree--;
 992                                if (!pn->indegree) {
 993                                        if (!lifo)
 994                                                insert_by_date(parent, &work);
 995                                        else
 996                                                commit_list_insert(parent, &work);
 997                                }
 998                        }
 999                        parents=parents->next;
1000                }
1001                /*
1002                 * work_item is a commit all of whose children
1003                 * have already been emitted. we can emit it now.
1004                 */
1005                *pptr = work_node->list_item;
1006                pptr = &(*pptr)->next;
1007                *pptr = NULL;
1008                setter(work_item, NULL);
1009        }
1010        free(nodes);
1011}
1012
1013/* merge-rebase stuff */
1014
1015/* bits #0..15 in revision.h */
1016#define PARENT1         (1u<<16)
1017#define PARENT2         (1u<<17)
1018#define STALE           (1u<<18)
1019#define RESULT          (1u<<19)
1020
1021static struct commit *interesting(struct commit_list *list)
1022{
1023        while (list) {
1024                struct commit *commit = list->item;
1025                list = list->next;
1026                if (commit->object.flags & STALE)
1027                        continue;
1028                return commit;
1029        }
1030        return NULL;
1031}
1032
1033static struct commit_list *merge_bases(struct commit *one, struct commit *two)
1034{
1035        struct commit_list *list = NULL;
1036        struct commit_list *result = NULL;
1037
1038        if (one == two)
1039                /* We do not mark this even with RESULT so we do not
1040                 * have to clean it up.
1041                 */
1042                return commit_list_insert(one, &result);
1043
1044        parse_commit(one);
1045        parse_commit(two);
1046
1047        one->object.flags |= PARENT1;
1048        two->object.flags |= PARENT2;
1049        insert_by_date(one, &list);
1050        insert_by_date(two, &list);
1051
1052        while (interesting(list)) {
1053                struct commit *commit;
1054                struct commit_list *parents;
1055                struct commit_list *n;
1056                int flags;
1057
1058                commit = list->item;
1059                n = list->next;
1060                free(list);
1061                list = n;
1062
1063                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
1064                if (flags == (PARENT1 | PARENT2)) {
1065                        if (!(commit->object.flags & RESULT)) {
1066                                commit->object.flags |= RESULT;
1067                                insert_by_date(commit, &result);
1068                        }
1069                        /* Mark parents of a found merge stale */
1070                        flags |= STALE;
1071                }
1072                parents = commit->parents;
1073                while (parents) {
1074                        struct commit *p = parents->item;
1075                        parents = parents->next;
1076                        if ((p->object.flags & flags) == flags)
1077                                continue;
1078                        parse_commit(p);
1079                        p->object.flags |= flags;
1080                        insert_by_date(p, &list);
1081                }
1082        }
1083
1084        /* Clean up the result to remove stale ones */
1085        list = result; result = NULL;
1086        while (list) {
1087                struct commit_list *n = list->next;
1088                if (!(list->item->object.flags & STALE))
1089                        insert_by_date(list->item, &result);
1090                free(list);
1091                list = n;
1092        }
1093        return result;
1094}
1095
1096struct commit_list *get_merge_bases(struct commit *one,
1097                                    struct commit *two,
1098                                    int cleanup)
1099{
1100        const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
1101        struct commit_list *list;
1102        struct commit **rslt;
1103        struct commit_list *result;
1104        int cnt, i, j;
1105
1106        result = merge_bases(one, two);
1107        if (one == two)
1108                return result;
1109        if (!result || !result->next) {
1110                if (cleanup) {
1111                        clear_commit_marks(one, all_flags);
1112                        clear_commit_marks(two, all_flags);
1113                }
1114                return result;
1115        }
1116
1117        /* There are more than one */
1118        cnt = 0;
1119        list = result;
1120        while (list) {
1121                list = list->next;
1122                cnt++;
1123        }
1124        rslt = xcalloc(cnt, sizeof(*rslt));
1125        for (list = result, i = 0; list; list = list->next)
1126                rslt[i++] = list->item;
1127        free_commit_list(result);
1128
1129        clear_commit_marks(one, all_flags);
1130        clear_commit_marks(two, all_flags);
1131        for (i = 0; i < cnt - 1; i++) {
1132                for (j = i+1; j < cnt; j++) {
1133                        if (!rslt[i] || !rslt[j])
1134                                continue;
1135                        result = merge_bases(rslt[i], rslt[j]);
1136                        clear_commit_marks(rslt[i], all_flags);
1137                        clear_commit_marks(rslt[j], all_flags);
1138                        for (list = result; list; list = list->next) {
1139                                if (rslt[i] == list->item)
1140                                        rslt[i] = NULL;
1141                                if (rslt[j] == list->item)
1142                                        rslt[j] = NULL;
1143                        }
1144                }
1145        }
1146
1147        /* Surviving ones in rslt[] are the independent results */
1148        result = NULL;
1149        for (i = 0; i < cnt; i++) {
1150                if (rslt[i])
1151                        insert_by_date(rslt[i], &result);
1152        }
1153        free(rslt);
1154        return result;
1155}
1156
1157int in_merge_bases(struct commit *rev1, struct commit *rev2)
1158{
1159        struct commit_list *bases, *b;
1160        int ret = 0;
1161
1162        bases = get_merge_bases(rev1, rev2, 1);
1163        for (b = bases; b; b = b->next) {
1164                if (!hashcmp(rev1->object.sha1, b->item->object.sha1)) {
1165                        ret = 1;
1166                        break;
1167                }
1168        }
1169
1170        free_commit_list(bases);
1171        return ret;
1172}