blame.con commit Merge branch 'js/pack-objects-mutex-init-fix' (620b00e)
   1#include "cache.h"
   2#include "refs.h"
   3#include "object-store.h"
   4#include "cache-tree.h"
   5#include "mergesort.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "tag.h"
   9#include "blame.h"
  10#include "alloc.h"
  11#include "commit-slab.h"
  12
  13define_commit_slab(blame_suspects, struct blame_origin *);
  14static struct blame_suspects blame_suspects;
  15
  16struct blame_origin *get_blame_suspects(struct commit *commit)
  17{
  18        struct blame_origin **result;
  19
  20        result = blame_suspects_peek(&blame_suspects, commit);
  21
  22        return result ? *result : NULL;
  23}
  24
  25static void set_blame_suspects(struct commit *commit, struct blame_origin *origin)
  26{
  27        *blame_suspects_at(&blame_suspects, commit) = origin;
  28}
  29
  30void blame_origin_decref(struct blame_origin *o)
  31{
  32        if (o && --o->refcnt <= 0) {
  33                struct blame_origin *p, *l = NULL;
  34                if (o->previous)
  35                        blame_origin_decref(o->previous);
  36                free(o->file.ptr);
  37                /* Should be present exactly once in commit chain */
  38                for (p = get_blame_suspects(o->commit); p; l = p, p = p->next) {
  39                        if (p == o) {
  40                                if (l)
  41                                        l->next = p->next;
  42                                else
  43                                        set_blame_suspects(o->commit, p->next);
  44                                free(o);
  45                                return;
  46                        }
  47                }
  48                die("internal error in blame_origin_decref");
  49        }
  50}
  51
  52/*
  53 * Given a commit and a path in it, create a new origin structure.
  54 * The callers that add blame to the scoreboard should use
  55 * get_origin() to obtain shared, refcounted copy instead of calling
  56 * this function directly.
  57 */
  58static struct blame_origin *make_origin(struct commit *commit, const char *path)
  59{
  60        struct blame_origin *o;
  61        FLEX_ALLOC_STR(o, path, path);
  62        o->commit = commit;
  63        o->refcnt = 1;
  64        o->next = get_blame_suspects(commit);
  65        set_blame_suspects(commit, o);
  66        return o;
  67}
  68
  69/*
  70 * Locate an existing origin or create a new one.
  71 * This moves the origin to front position in the commit util list.
  72 */
  73static struct blame_origin *get_origin(struct commit *commit, const char *path)
  74{
  75        struct blame_origin *o, *l;
  76
  77        for (o = get_blame_suspects(commit), l = NULL; o; l = o, o = o->next) {
  78                if (!strcmp(o->path, path)) {
  79                        /* bump to front */
  80                        if (l) {
  81                                l->next = o->next;
  82                                o->next = get_blame_suspects(commit);
  83                                set_blame_suspects(commit, o);
  84                        }
  85                        return blame_origin_incref(o);
  86                }
  87        }
  88        return make_origin(commit, path);
  89}
  90
  91
  92
  93static void verify_working_tree_path(struct repository *r,
  94                                     struct commit *work_tree, const char *path)
  95{
  96        struct commit_list *parents;
  97        int pos;
  98
  99        for (parents = work_tree->parents; parents; parents = parents->next) {
 100                const struct object_id *commit_oid = &parents->item->object.oid;
 101                struct object_id blob_oid;
 102                unsigned mode;
 103
 104                if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
 105                    oid_object_info(r, &blob_oid, NULL) == OBJ_BLOB)
 106                        return;
 107        }
 108
 109        pos = index_name_pos(r->index, path, strlen(path));
 110        if (pos >= 0)
 111                ; /* path is in the index */
 112        else if (-1 - pos < r->index->cache_nr &&
 113                 !strcmp(r->index->cache[-1 - pos]->name, path))
 114                ; /* path is in the index, unmerged */
 115        else
 116                die("no such path '%s' in HEAD", path);
 117}
 118
 119static struct commit_list **append_parent(struct commit_list **tail, const struct object_id *oid)
 120{
 121        struct commit *parent;
 122
 123        parent = lookup_commit_reference(the_repository, oid);
 124        if (!parent)
 125                die("no such commit %s", oid_to_hex(oid));
 126        return &commit_list_insert(parent, tail)->next;
 127}
 128
 129static void append_merge_parents(struct commit_list **tail)
 130{
 131        int merge_head;
 132        struct strbuf line = STRBUF_INIT;
 133
 134        merge_head = open(git_path_merge_head(the_repository), O_RDONLY);
 135        if (merge_head < 0) {
 136                if (errno == ENOENT)
 137                        return;
 138                die("cannot open '%s' for reading",
 139                    git_path_merge_head(the_repository));
 140        }
 141
 142        while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
 143                struct object_id oid;
 144                if (line.len < GIT_SHA1_HEXSZ || get_oid_hex(line.buf, &oid))
 145                        die("unknown line in '%s': %s",
 146                            git_path_merge_head(the_repository), line.buf);
 147                tail = append_parent(tail, &oid);
 148        }
 149        close(merge_head);
 150        strbuf_release(&line);
 151}
 152
 153/*
 154 * This isn't as simple as passing sb->buf and sb->len, because we
 155 * want to transfer ownership of the buffer to the commit (so we
 156 * must use detach).
 157 */
 158static void set_commit_buffer_from_strbuf(struct commit *c, struct strbuf *sb)
 159{
 160        size_t len;
 161        void *buf = strbuf_detach(sb, &len);
 162        set_commit_buffer(the_repository, c, buf, len);
 163}
 164
 165/*
 166 * Prepare a dummy commit that represents the work tree (or staged) item.
 167 * Note that annotating work tree item never works in the reverse.
 168 */
 169static struct commit *fake_working_tree_commit(struct repository *r,
 170                                               struct diff_options *opt,
 171                                               const char *path,
 172                                               const char *contents_from)
 173{
 174        struct commit *commit;
 175        struct blame_origin *origin;
 176        struct commit_list **parent_tail, *parent;
 177        struct object_id head_oid;
 178        struct strbuf buf = STRBUF_INIT;
 179        const char *ident;
 180        time_t now;
 181        int len;
 182        struct cache_entry *ce;
 183        unsigned mode;
 184        struct strbuf msg = STRBUF_INIT;
 185
 186        read_index(r->index);
 187        time(&now);
 188        commit = alloc_commit_node(the_repository);
 189        commit->object.parsed = 1;
 190        commit->date = now;
 191        parent_tail = &commit->parents;
 192
 193        if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
 194                die("no such ref: HEAD");
 195
 196        parent_tail = append_parent(parent_tail, &head_oid);
 197        append_merge_parents(parent_tail);
 198        verify_working_tree_path(r, commit, path);
 199
 200        origin = make_origin(commit, path);
 201
 202        ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0);
 203        strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
 204        for (parent = commit->parents; parent; parent = parent->next)
 205                strbuf_addf(&msg, "parent %s\n",
 206                            oid_to_hex(&parent->item->object.oid));
 207        strbuf_addf(&msg,
 208                    "author %s\n"
 209                    "committer %s\n\n"
 210                    "Version of %s from %s\n",
 211                    ident, ident, path,
 212                    (!contents_from ? path :
 213                     (!strcmp(contents_from, "-") ? "standard input" : contents_from)));
 214        set_commit_buffer_from_strbuf(commit, &msg);
 215
 216        if (!contents_from || strcmp("-", contents_from)) {
 217                struct stat st;
 218                const char *read_from;
 219                char *buf_ptr;
 220                unsigned long buf_len;
 221
 222                if (contents_from) {
 223                        if (stat(contents_from, &st) < 0)
 224                                die_errno("Cannot stat '%s'", contents_from);
 225                        read_from = contents_from;
 226                }
 227                else {
 228                        if (lstat(path, &st) < 0)
 229                                die_errno("Cannot lstat '%s'", path);
 230                        read_from = path;
 231                }
 232                mode = canon_mode(st.st_mode);
 233
 234                switch (st.st_mode & S_IFMT) {
 235                case S_IFREG:
 236                        if (opt->flags.allow_textconv &&
 237                            textconv_object(r, read_from, mode, &null_oid, 0, &buf_ptr, &buf_len))
 238                                strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1);
 239                        else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
 240                                die_errno("cannot open or read '%s'", read_from);
 241                        break;
 242                case S_IFLNK:
 243                        if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
 244                                die_errno("cannot readlink '%s'", read_from);
 245                        break;
 246                default:
 247                        die("unsupported file type %s", read_from);
 248                }
 249        }
 250        else {
 251                /* Reading from stdin */
 252                mode = 0;
 253                if (strbuf_read(&buf, 0, 0) < 0)
 254                        die_errno("failed to read from stdin");
 255        }
 256        convert_to_git(r->index, path, buf.buf, buf.len, &buf, 0);
 257        origin->file.ptr = buf.buf;
 258        origin->file.size = buf.len;
 259        pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
 260
 261        /*
 262         * Read the current index, replace the path entry with
 263         * origin->blob_sha1 without mucking with its mode or type
 264         * bits; we are not going to write this index out -- we just
 265         * want to run "diff-index --cached".
 266         */
 267        discard_index(r->index);
 268        read_index(r->index);
 269
 270        len = strlen(path);
 271        if (!mode) {
 272                int pos = index_name_pos(r->index, path, len);
 273                if (0 <= pos)
 274                        mode = r->index->cache[pos]->ce_mode;
 275                else
 276                        /* Let's not bother reading from HEAD tree */
 277                        mode = S_IFREG | 0644;
 278        }
 279        ce = make_empty_cache_entry(r->index, len);
 280        oidcpy(&ce->oid, &origin->blob_oid);
 281        memcpy(ce->name, path, len);
 282        ce->ce_flags = create_ce_flags(0);
 283        ce->ce_namelen = len;
 284        ce->ce_mode = create_ce_mode(mode);
 285        add_index_entry(r->index, ce,
 286                        ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 287
 288        cache_tree_invalidate_path(r->index, path);
 289
 290        return commit;
 291}
 292
 293
 294
 295static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b,
 296                      xdl_emit_hunk_consume_func_t hunk_func, void *cb_data, int xdl_opts)
 297{
 298        xpparam_t xpp = {0};
 299        xdemitconf_t xecfg = {0};
 300        xdemitcb_t ecb = {NULL};
 301
 302        xpp.flags = xdl_opts;
 303        xecfg.hunk_func = hunk_func;
 304        ecb.priv = cb_data;
 305        return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
 306}
 307
 308/*
 309 * Given an origin, prepare mmfile_t structure to be used by the
 310 * diff machinery
 311 */
 312static void fill_origin_blob(struct diff_options *opt,
 313                             struct blame_origin *o, mmfile_t *file, int *num_read_blob)
 314{
 315        if (!o->file.ptr) {
 316                enum object_type type;
 317                unsigned long file_size;
 318
 319                (*num_read_blob)++;
 320                if (opt->flags.allow_textconv &&
 321                    textconv_object(opt->repo, o->path, o->mode,
 322                                    &o->blob_oid, 1, &file->ptr, &file_size))
 323                        ;
 324                else
 325                        file->ptr = read_object_file(&o->blob_oid, &type,
 326                                                     &file_size);
 327                file->size = file_size;
 328
 329                if (!file->ptr)
 330                        die("Cannot read blob %s for path %s",
 331                            oid_to_hex(&o->blob_oid),
 332                            o->path);
 333                o->file = *file;
 334        }
 335        else
 336                *file = o->file;
 337}
 338
 339static void drop_origin_blob(struct blame_origin *o)
 340{
 341        FREE_AND_NULL(o->file.ptr);
 342}
 343
 344/*
 345 * Any merge of blames happens on lists of blames that arrived via
 346 * different parents in a single suspect.  In this case, we want to
 347 * sort according to the suspect line numbers as opposed to the final
 348 * image line numbers.  The function body is somewhat longish because
 349 * it avoids unnecessary writes.
 350 */
 351
 352static struct blame_entry *blame_merge(struct blame_entry *list1,
 353                                       struct blame_entry *list2)
 354{
 355        struct blame_entry *p1 = list1, *p2 = list2,
 356                **tail = &list1;
 357
 358        if (!p1)
 359                return p2;
 360        if (!p2)
 361                return p1;
 362
 363        if (p1->s_lno <= p2->s_lno) {
 364                do {
 365                        tail = &p1->next;
 366                        if ((p1 = *tail) == NULL) {
 367                                *tail = p2;
 368                                return list1;
 369                        }
 370                } while (p1->s_lno <= p2->s_lno);
 371        }
 372        for (;;) {
 373                *tail = p2;
 374                do {
 375                        tail = &p2->next;
 376                        if ((p2 = *tail) == NULL)  {
 377                                *tail = p1;
 378                                return list1;
 379                        }
 380                } while (p1->s_lno > p2->s_lno);
 381                *tail = p1;
 382                do {
 383                        tail = &p1->next;
 384                        if ((p1 = *tail) == NULL) {
 385                                *tail = p2;
 386                                return list1;
 387                        }
 388                } while (p1->s_lno <= p2->s_lno);
 389        }
 390}
 391
 392static void *get_next_blame(const void *p)
 393{
 394        return ((struct blame_entry *)p)->next;
 395}
 396
 397static void set_next_blame(void *p1, void *p2)
 398{
 399        ((struct blame_entry *)p1)->next = p2;
 400}
 401
 402/*
 403 * Final image line numbers are all different, so we don't need a
 404 * three-way comparison here.
 405 */
 406
 407static int compare_blame_final(const void *p1, const void *p2)
 408{
 409        return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
 410                ? 1 : -1;
 411}
 412
 413static int compare_blame_suspect(const void *p1, const void *p2)
 414{
 415        const struct blame_entry *s1 = p1, *s2 = p2;
 416        /*
 417         * to allow for collating suspects, we sort according to the
 418         * respective pointer value as the primary sorting criterion.
 419         * The actual relation is pretty unimportant as long as it
 420         * establishes a total order.  Comparing as integers gives us
 421         * that.
 422         */
 423        if (s1->suspect != s2->suspect)
 424                return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
 425        if (s1->s_lno == s2->s_lno)
 426                return 0;
 427        return s1->s_lno > s2->s_lno ? 1 : -1;
 428}
 429
 430void blame_sort_final(struct blame_scoreboard *sb)
 431{
 432        sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
 433                                  compare_blame_final);
 434}
 435
 436static int compare_commits_by_reverse_commit_date(const void *a,
 437                                                  const void *b,
 438                                                  void *c)
 439{
 440        return -compare_commits_by_commit_date(a, b, c);
 441}
 442
 443/*
 444 * For debugging -- origin is refcounted, and this asserts that
 445 * we do not underflow.
 446 */
 447static void sanity_check_refcnt(struct blame_scoreboard *sb)
 448{
 449        int baa = 0;
 450        struct blame_entry *ent;
 451
 452        for (ent = sb->ent; ent; ent = ent->next) {
 453                /* Nobody should have zero or negative refcnt */
 454                if (ent->suspect->refcnt <= 0) {
 455                        fprintf(stderr, "%s in %s has negative refcnt %d\n",
 456                                ent->suspect->path,
 457                                oid_to_hex(&ent->suspect->commit->object.oid),
 458                                ent->suspect->refcnt);
 459                        baa = 1;
 460                }
 461        }
 462        if (baa)
 463                sb->on_sanity_fail(sb, baa);
 464}
 465
 466/*
 467 * If two blame entries that are next to each other came from
 468 * contiguous lines in the same origin (i.e. <commit, path> pair),
 469 * merge them together.
 470 */
 471void blame_coalesce(struct blame_scoreboard *sb)
 472{
 473        struct blame_entry *ent, *next;
 474
 475        for (ent = sb->ent; ent && (next = ent->next); ent = next) {
 476                if (ent->suspect == next->suspect &&
 477                    ent->s_lno + ent->num_lines == next->s_lno) {
 478                        ent->num_lines += next->num_lines;
 479                        ent->next = next->next;
 480                        blame_origin_decref(next->suspect);
 481                        free(next);
 482                        ent->score = 0;
 483                        next = ent; /* again */
 484                }
 485        }
 486
 487        if (sb->debug) /* sanity */
 488                sanity_check_refcnt(sb);
 489}
 490
 491/*
 492 * Merge the given sorted list of blames into a preexisting origin.
 493 * If there were no previous blames to that commit, it is entered into
 494 * the commit priority queue of the score board.
 495 */
 496
 497static void queue_blames(struct blame_scoreboard *sb, struct blame_origin *porigin,
 498                         struct blame_entry *sorted)
 499{
 500        if (porigin->suspects)
 501                porigin->suspects = blame_merge(porigin->suspects, sorted);
 502        else {
 503                struct blame_origin *o;
 504                for (o = get_blame_suspects(porigin->commit); o; o = o->next) {
 505                        if (o->suspects) {
 506                                porigin->suspects = sorted;
 507                                return;
 508                        }
 509                }
 510                porigin->suspects = sorted;
 511                prio_queue_put(&sb->commits, porigin->commit);
 512        }
 513}
 514
 515/*
 516 * Fill the blob_sha1 field of an origin if it hasn't, so that later
 517 * call to fill_origin_blob() can use it to locate the data.  blob_sha1
 518 * for an origin is also used to pass the blame for the entire file to
 519 * the parent to detect the case where a child's blob is identical to
 520 * that of its parent's.
 521 *
 522 * This also fills origin->mode for corresponding tree path.
 523 */
 524static int fill_blob_sha1_and_mode(struct repository *r,
 525                                   struct blame_origin *origin)
 526{
 527        if (!is_null_oid(&origin->blob_oid))
 528                return 0;
 529        if (get_tree_entry(&origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode))
 530                goto error_out;
 531        if (oid_object_info(r, &origin->blob_oid, NULL) != OBJ_BLOB)
 532                goto error_out;
 533        return 0;
 534 error_out:
 535        oidclr(&origin->blob_oid);
 536        origin->mode = S_IFINVALID;
 537        return -1;
 538}
 539
 540/*
 541 * We have an origin -- check if the same path exists in the
 542 * parent and return an origin structure to represent it.
 543 */
 544static struct blame_origin *find_origin(struct repository *r,
 545                                        struct commit *parent,
 546                                        struct blame_origin *origin)
 547{
 548        struct blame_origin *porigin;
 549        struct diff_options diff_opts;
 550        const char *paths[2];
 551
 552        /* First check any existing origins */
 553        for (porigin = get_blame_suspects(parent); porigin; porigin = porigin->next)
 554                if (!strcmp(porigin->path, origin->path)) {
 555                        /*
 556                         * The same path between origin and its parent
 557                         * without renaming -- the most common case.
 558                         */
 559                        return blame_origin_incref (porigin);
 560                }
 561
 562        /* See if the origin->path is different between parent
 563         * and origin first.  Most of the time they are the
 564         * same and diff-tree is fairly efficient about this.
 565         */
 566        repo_diff_setup(r, &diff_opts);
 567        diff_opts.flags.recursive = 1;
 568        diff_opts.detect_rename = 0;
 569        diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 570        paths[0] = origin->path;
 571        paths[1] = NULL;
 572
 573        parse_pathspec(&diff_opts.pathspec,
 574                       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
 575                       PATHSPEC_LITERAL_PATH, "", paths);
 576        diff_setup_done(&diff_opts);
 577
 578        if (is_null_oid(&origin->commit->object.oid))
 579                do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 580        else
 581                diff_tree_oid(get_commit_tree_oid(parent),
 582                              get_commit_tree_oid(origin->commit),
 583                              "", &diff_opts);
 584        diffcore_std(&diff_opts);
 585
 586        if (!diff_queued_diff.nr) {
 587                /* The path is the same as parent */
 588                porigin = get_origin(parent, origin->path);
 589                oidcpy(&porigin->blob_oid, &origin->blob_oid);
 590                porigin->mode = origin->mode;
 591        } else {
 592                /*
 593                 * Since origin->path is a pathspec, if the parent
 594                 * commit had it as a directory, we will see a whole
 595                 * bunch of deletion of files in the directory that we
 596                 * do not care about.
 597                 */
 598                int i;
 599                struct diff_filepair *p = NULL;
 600                for (i = 0; i < diff_queued_diff.nr; i++) {
 601                        const char *name;
 602                        p = diff_queued_diff.queue[i];
 603                        name = p->one->path ? p->one->path : p->two->path;
 604                        if (!strcmp(name, origin->path))
 605                                break;
 606                }
 607                if (!p)
 608                        die("internal error in blame::find_origin");
 609                switch (p->status) {
 610                default:
 611                        die("internal error in blame::find_origin (%c)",
 612                            p->status);
 613                case 'M':
 614                        porigin = get_origin(parent, origin->path);
 615                        oidcpy(&porigin->blob_oid, &p->one->oid);
 616                        porigin->mode = p->one->mode;
 617                        break;
 618                case 'A':
 619                case 'T':
 620                        /* Did not exist in parent, or type changed */
 621                        break;
 622                }
 623        }
 624        diff_flush(&diff_opts);
 625        clear_pathspec(&diff_opts.pathspec);
 626        return porigin;
 627}
 628
 629/*
 630 * We have an origin -- find the path that corresponds to it in its
 631 * parent and return an origin structure to represent it.
 632 */
 633static struct blame_origin *find_rename(struct repository *r,
 634                                        struct commit *parent,
 635                                        struct blame_origin *origin)
 636{
 637        struct blame_origin *porigin = NULL;
 638        struct diff_options diff_opts;
 639        int i;
 640
 641        repo_diff_setup(r, &diff_opts);
 642        diff_opts.flags.recursive = 1;
 643        diff_opts.detect_rename = DIFF_DETECT_RENAME;
 644        diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 645        diff_opts.single_follow = origin->path;
 646        diff_setup_done(&diff_opts);
 647
 648        if (is_null_oid(&origin->commit->object.oid))
 649                do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 650        else
 651                diff_tree_oid(get_commit_tree_oid(parent),
 652                              get_commit_tree_oid(origin->commit),
 653                              "", &diff_opts);
 654        diffcore_std(&diff_opts);
 655
 656        for (i = 0; i < diff_queued_diff.nr; i++) {
 657                struct diff_filepair *p = diff_queued_diff.queue[i];
 658                if ((p->status == 'R' || p->status == 'C') &&
 659                    !strcmp(p->two->path, origin->path)) {
 660                        porigin = get_origin(parent, p->one->path);
 661                        oidcpy(&porigin->blob_oid, &p->one->oid);
 662                        porigin->mode = p->one->mode;
 663                        break;
 664                }
 665        }
 666        diff_flush(&diff_opts);
 667        clear_pathspec(&diff_opts.pathspec);
 668        return porigin;
 669}
 670
 671/*
 672 * Append a new blame entry to a given output queue.
 673 */
 674static void add_blame_entry(struct blame_entry ***queue,
 675                            const struct blame_entry *src)
 676{
 677        struct blame_entry *e = xmalloc(sizeof(*e));
 678        memcpy(e, src, sizeof(*e));
 679        blame_origin_incref(e->suspect);
 680
 681        e->next = **queue;
 682        **queue = e;
 683        *queue = &e->next;
 684}
 685
 686/*
 687 * src typically is on-stack; we want to copy the information in it to
 688 * a malloced blame_entry that gets added to the given queue.  The
 689 * origin of dst loses a refcnt.
 690 */
 691static void dup_entry(struct blame_entry ***queue,
 692                      struct blame_entry *dst, struct blame_entry *src)
 693{
 694        blame_origin_incref(src->suspect);
 695        blame_origin_decref(dst->suspect);
 696        memcpy(dst, src, sizeof(*src));
 697        dst->next = **queue;
 698        **queue = dst;
 699        *queue = &dst->next;
 700}
 701
 702const char *blame_nth_line(struct blame_scoreboard *sb, long lno)
 703{
 704        return sb->final_buf + sb->lineno[lno];
 705}
 706
 707/*
 708 * It is known that lines between tlno to same came from parent, and e
 709 * has an overlap with that range.  it also is known that parent's
 710 * line plno corresponds to e's line tlno.
 711 *
 712 *                <---- e ----->
 713 *                   <------>
 714 *                   <------------>
 715 *             <------------>
 716 *             <------------------>
 717 *
 718 * Split e into potentially three parts; before this chunk, the chunk
 719 * to be blamed for the parent, and after that portion.
 720 */
 721static void split_overlap(struct blame_entry *split,
 722                          struct blame_entry *e,
 723                          int tlno, int plno, int same,
 724                          struct blame_origin *parent)
 725{
 726        int chunk_end_lno;
 727        memset(split, 0, sizeof(struct blame_entry [3]));
 728
 729        if (e->s_lno < tlno) {
 730                /* there is a pre-chunk part not blamed on parent */
 731                split[0].suspect = blame_origin_incref(e->suspect);
 732                split[0].lno = e->lno;
 733                split[0].s_lno = e->s_lno;
 734                split[0].num_lines = tlno - e->s_lno;
 735                split[1].lno = e->lno + tlno - e->s_lno;
 736                split[1].s_lno = plno;
 737        }
 738        else {
 739                split[1].lno = e->lno;
 740                split[1].s_lno = plno + (e->s_lno - tlno);
 741        }
 742
 743        if (same < e->s_lno + e->num_lines) {
 744                /* there is a post-chunk part not blamed on parent */
 745                split[2].suspect = blame_origin_incref(e->suspect);
 746                split[2].lno = e->lno + (same - e->s_lno);
 747                split[2].s_lno = e->s_lno + (same - e->s_lno);
 748                split[2].num_lines = e->s_lno + e->num_lines - same;
 749                chunk_end_lno = split[2].lno;
 750        }
 751        else
 752                chunk_end_lno = e->lno + e->num_lines;
 753        split[1].num_lines = chunk_end_lno - split[1].lno;
 754
 755        /*
 756         * if it turns out there is nothing to blame the parent for,
 757         * forget about the splitting.  !split[1].suspect signals this.
 758         */
 759        if (split[1].num_lines < 1)
 760                return;
 761        split[1].suspect = blame_origin_incref(parent);
 762}
 763
 764/*
 765 * split_overlap() divided an existing blame e into up to three parts
 766 * in split.  Any assigned blame is moved to queue to
 767 * reflect the split.
 768 */
 769static void split_blame(struct blame_entry ***blamed,
 770                        struct blame_entry ***unblamed,
 771                        struct blame_entry *split,
 772                        struct blame_entry *e)
 773{
 774        if (split[0].suspect && split[2].suspect) {
 775                /* The first part (reuse storage for the existing entry e) */
 776                dup_entry(unblamed, e, &split[0]);
 777
 778                /* The last part -- me */
 779                add_blame_entry(unblamed, &split[2]);
 780
 781                /* ... and the middle part -- parent */
 782                add_blame_entry(blamed, &split[1]);
 783        }
 784        else if (!split[0].suspect && !split[2].suspect)
 785                /*
 786                 * The parent covers the entire area; reuse storage for
 787                 * e and replace it with the parent.
 788                 */
 789                dup_entry(blamed, e, &split[1]);
 790        else if (split[0].suspect) {
 791                /* me and then parent */
 792                dup_entry(unblamed, e, &split[0]);
 793                add_blame_entry(blamed, &split[1]);
 794        }
 795        else {
 796                /* parent and then me */
 797                dup_entry(blamed, e, &split[1]);
 798                add_blame_entry(unblamed, &split[2]);
 799        }
 800}
 801
 802/*
 803 * After splitting the blame, the origins used by the
 804 * on-stack blame_entry should lose one refcnt each.
 805 */
 806static void decref_split(struct blame_entry *split)
 807{
 808        int i;
 809
 810        for (i = 0; i < 3; i++)
 811                blame_origin_decref(split[i].suspect);
 812}
 813
 814/*
 815 * reverse_blame reverses the list given in head, appending tail.
 816 * That allows us to build lists in reverse order, then reverse them
 817 * afterwards.  This can be faster than building the list in proper
 818 * order right away.  The reason is that building in proper order
 819 * requires writing a link in the _previous_ element, while building
 820 * in reverse order just requires placing the list head into the
 821 * _current_ element.
 822 */
 823
 824static struct blame_entry *reverse_blame(struct blame_entry *head,
 825                                         struct blame_entry *tail)
 826{
 827        while (head) {
 828                struct blame_entry *next = head->next;
 829                head->next = tail;
 830                tail = head;
 831                head = next;
 832        }
 833        return tail;
 834}
 835
 836/*
 837 * Process one hunk from the patch between the current suspect for
 838 * blame_entry e and its parent.  This first blames any unfinished
 839 * entries before the chunk (which is where target and parent start
 840 * differing) on the parent, and then splits blame entries at the
 841 * start and at the end of the difference region.  Since use of -M and
 842 * -C options may lead to overlapping/duplicate source line number
 843 * ranges, all we can rely on from sorting/merging is the order of the
 844 * first suspect line number.
 845 */
 846static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
 847                        int tlno, int offset, int same,
 848                        struct blame_origin *parent)
 849{
 850        struct blame_entry *e = **srcq;
 851        struct blame_entry *samep = NULL, *diffp = NULL;
 852
 853        while (e && e->s_lno < tlno) {
 854                struct blame_entry *next = e->next;
 855                /*
 856                 * current record starts before differing portion.  If
 857                 * it reaches into it, we need to split it up and
 858                 * examine the second part separately.
 859                 */
 860                if (e->s_lno + e->num_lines > tlno) {
 861                        /* Move second half to a new record */
 862                        int len = tlno - e->s_lno;
 863                        struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
 864                        n->suspect = e->suspect;
 865                        n->lno = e->lno + len;
 866                        n->s_lno = e->s_lno + len;
 867                        n->num_lines = e->num_lines - len;
 868                        e->num_lines = len;
 869                        e->score = 0;
 870                        /* Push new record to diffp */
 871                        n->next = diffp;
 872                        diffp = n;
 873                } else
 874                        blame_origin_decref(e->suspect);
 875                /* Pass blame for everything before the differing
 876                 * chunk to the parent */
 877                e->suspect = blame_origin_incref(parent);
 878                e->s_lno += offset;
 879                e->next = samep;
 880                samep = e;
 881                e = next;
 882        }
 883        /*
 884         * As we don't know how much of a common stretch after this
 885         * diff will occur, the currently blamed parts are all that we
 886         * can assign to the parent for now.
 887         */
 888
 889        if (samep) {
 890                **dstq = reverse_blame(samep, **dstq);
 891                *dstq = &samep->next;
 892        }
 893        /*
 894         * Prepend the split off portions: everything after e starts
 895         * after the blameable portion.
 896         */
 897        e = reverse_blame(diffp, e);
 898
 899        /*
 900         * Now retain records on the target while parts are different
 901         * from the parent.
 902         */
 903        samep = NULL;
 904        diffp = NULL;
 905        while (e && e->s_lno < same) {
 906                struct blame_entry *next = e->next;
 907
 908                /*
 909                 * If current record extends into sameness, need to split.
 910                 */
 911                if (e->s_lno + e->num_lines > same) {
 912                        /*
 913                         * Move second half to a new record to be
 914                         * processed by later chunks
 915                         */
 916                        int len = same - e->s_lno;
 917                        struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
 918                        n->suspect = blame_origin_incref(e->suspect);
 919                        n->lno = e->lno + len;
 920                        n->s_lno = e->s_lno + len;
 921                        n->num_lines = e->num_lines - len;
 922                        e->num_lines = len;
 923                        e->score = 0;
 924                        /* Push new record to samep */
 925                        n->next = samep;
 926                        samep = n;
 927                }
 928                e->next = diffp;
 929                diffp = e;
 930                e = next;
 931        }
 932        **srcq = reverse_blame(diffp, reverse_blame(samep, e));
 933        /* Move across elements that are in the unblamable portion */
 934        if (diffp)
 935                *srcq = &diffp->next;
 936}
 937
 938struct blame_chunk_cb_data {
 939        struct blame_origin *parent;
 940        long offset;
 941        struct blame_entry **dstq;
 942        struct blame_entry **srcq;
 943};
 944
 945/* diff chunks are from parent to target */
 946static int blame_chunk_cb(long start_a, long count_a,
 947                          long start_b, long count_b, void *data)
 948{
 949        struct blame_chunk_cb_data *d = data;
 950        if (start_a - start_b != d->offset)
 951                die("internal error in blame::blame_chunk_cb");
 952        blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
 953                    start_b + count_b, d->parent);
 954        d->offset = start_a + count_a - (start_b + count_b);
 955        return 0;
 956}
 957
 958/*
 959 * We are looking at the origin 'target' and aiming to pass blame
 960 * for the lines it is suspected to its parent.  Run diff to find
 961 * which lines came from parent and pass blame for them.
 962 */
 963static void pass_blame_to_parent(struct blame_scoreboard *sb,
 964                                 struct blame_origin *target,
 965                                 struct blame_origin *parent)
 966{
 967        mmfile_t file_p, file_o;
 968        struct blame_chunk_cb_data d;
 969        struct blame_entry *newdest = NULL;
 970
 971        if (!target->suspects)
 972                return; /* nothing remains for this target */
 973
 974        d.parent = parent;
 975        d.offset = 0;
 976        d.dstq = &newdest; d.srcq = &target->suspects;
 977
 978        fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
 979        fill_origin_blob(&sb->revs->diffopt, target, &file_o, &sb->num_read_blob);
 980        sb->num_get_patch++;
 981
 982        if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, sb->xdl_opts))
 983                die("unable to generate diff (%s -> %s)",
 984                    oid_to_hex(&parent->commit->object.oid),
 985                    oid_to_hex(&target->commit->object.oid));
 986        /* The rest are the same as the parent */
 987        blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
 988        *d.dstq = NULL;
 989        queue_blames(sb, parent, newdest);
 990
 991        return;
 992}
 993
 994/*
 995 * The lines in blame_entry after splitting blames many times can become
 996 * very small and trivial, and at some point it becomes pointless to
 997 * blame the parents.  E.g. "\t\t}\n\t}\n\n" appears everywhere in any
 998 * ordinary C program, and it is not worth to say it was copied from
 999 * totally unrelated file in the parent.
1000 *
1001 * Compute how trivial the lines in the blame_entry are.
1002 */
1003unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e)
1004{
1005        unsigned score;
1006        const char *cp, *ep;
1007
1008        if (e->score)
1009                return e->score;
1010
1011        score = 1;
1012        cp = blame_nth_line(sb, e->lno);
1013        ep = blame_nth_line(sb, e->lno + e->num_lines);
1014        while (cp < ep) {
1015                unsigned ch = *((unsigned char *)cp);
1016                if (isalnum(ch))
1017                        score++;
1018                cp++;
1019        }
1020        e->score = score;
1021        return score;
1022}
1023
1024/*
1025 * best_so_far[] and potential[] are both a split of an existing blame_entry
1026 * that passes blame to the parent.  Maintain best_so_far the best split so
1027 * far, by comparing potential and best_so_far and copying potential into
1028 * bst_so_far as needed.
1029 */
1030static void copy_split_if_better(struct blame_scoreboard *sb,
1031                                 struct blame_entry *best_so_far,
1032                                 struct blame_entry *potential)
1033{
1034        int i;
1035
1036        if (!potential[1].suspect)
1037                return;
1038        if (best_so_far[1].suspect) {
1039                if (blame_entry_score(sb, &potential[1]) <
1040                    blame_entry_score(sb, &best_so_far[1]))
1041                        return;
1042        }
1043
1044        for (i = 0; i < 3; i++)
1045                blame_origin_incref(potential[i].suspect);
1046        decref_split(best_so_far);
1047        memcpy(best_so_far, potential, sizeof(struct blame_entry[3]));
1048}
1049
1050/*
1051 * We are looking at a part of the final image represented by
1052 * ent (tlno and same are offset by ent->s_lno).
1053 * tlno is where we are looking at in the final image.
1054 * up to (but not including) same match preimage.
1055 * plno is where we are looking at in the preimage.
1056 *
1057 * <-------------- final image ---------------------->
1058 *       <------ent------>
1059 *         ^tlno ^same
1060 *    <---------preimage----->
1061 *         ^plno
1062 *
1063 * All line numbers are 0-based.
1064 */
1065static void handle_split(struct blame_scoreboard *sb,
1066                         struct blame_entry *ent,
1067                         int tlno, int plno, int same,
1068                         struct blame_origin *parent,
1069                         struct blame_entry *split)
1070{
1071        if (ent->num_lines <= tlno)
1072                return;
1073        if (tlno < same) {
1074                struct blame_entry potential[3];
1075                tlno += ent->s_lno;
1076                same += ent->s_lno;
1077                split_overlap(potential, ent, tlno, plno, same, parent);
1078                copy_split_if_better(sb, split, potential);
1079                decref_split(potential);
1080        }
1081}
1082
1083struct handle_split_cb_data {
1084        struct blame_scoreboard *sb;
1085        struct blame_entry *ent;
1086        struct blame_origin *parent;
1087        struct blame_entry *split;
1088        long plno;
1089        long tlno;
1090};
1091
1092static int handle_split_cb(long start_a, long count_a,
1093                           long start_b, long count_b, void *data)
1094{
1095        struct handle_split_cb_data *d = data;
1096        handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
1097                     d->split);
1098        d->plno = start_a + count_a;
1099        d->tlno = start_b + count_b;
1100        return 0;
1101}
1102
1103/*
1104 * Find the lines from parent that are the same as ent so that
1105 * we can pass blames to it.  file_p has the blob contents for
1106 * the parent.
1107 */
1108static void find_copy_in_blob(struct blame_scoreboard *sb,
1109                              struct blame_entry *ent,
1110                              struct blame_origin *parent,
1111                              struct blame_entry *split,
1112                              mmfile_t *file_p)
1113{
1114        const char *cp;
1115        mmfile_t file_o;
1116        struct handle_split_cb_data d;
1117
1118        memset(&d, 0, sizeof(d));
1119        d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
1120        /*
1121         * Prepare mmfile that contains only the lines in ent.
1122         */
1123        cp = blame_nth_line(sb, ent->lno);
1124        file_o.ptr = (char *) cp;
1125        file_o.size = blame_nth_line(sb, ent->lno + ent->num_lines) - cp;
1126
1127        /*
1128         * file_o is a part of final image we are annotating.
1129         * file_p partially may match that image.
1130         */
1131        memset(split, 0, sizeof(struct blame_entry [3]));
1132        if (diff_hunks(file_p, &file_o, handle_split_cb, &d, sb->xdl_opts))
1133                die("unable to generate diff (%s)",
1134                    oid_to_hex(&parent->commit->object.oid));
1135        /* remainder, if any, all match the preimage */
1136        handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
1137}
1138
1139/* Move all blame entries from list *source that have a score smaller
1140 * than score_min to the front of list *small.
1141 * Returns a pointer to the link pointing to the old head of the small list.
1142 */
1143
1144static struct blame_entry **filter_small(struct blame_scoreboard *sb,
1145                                         struct blame_entry **small,
1146                                         struct blame_entry **source,
1147                                         unsigned score_min)
1148{
1149        struct blame_entry *p = *source;
1150        struct blame_entry *oldsmall = *small;
1151        while (p) {
1152                if (blame_entry_score(sb, p) <= score_min) {
1153                        *small = p;
1154                        small = &p->next;
1155                        p = *small;
1156                } else {
1157                        *source = p;
1158                        source = &p->next;
1159                        p = *source;
1160                }
1161        }
1162        *small = oldsmall;
1163        *source = NULL;
1164        return small;
1165}
1166
1167/*
1168 * See if lines currently target is suspected for can be attributed to
1169 * parent.
1170 */
1171static void find_move_in_parent(struct blame_scoreboard *sb,
1172                                struct blame_entry ***blamed,
1173                                struct blame_entry **toosmall,
1174                                struct blame_origin *target,
1175                                struct blame_origin *parent)
1176{
1177        struct blame_entry *e, split[3];
1178        struct blame_entry *unblamed = target->suspects;
1179        struct blame_entry *leftover = NULL;
1180        mmfile_t file_p;
1181
1182        if (!unblamed)
1183                return; /* nothing remains for this target */
1184
1185        fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
1186        if (!file_p.ptr)
1187                return;
1188
1189        /* At each iteration, unblamed has a NULL-terminated list of
1190         * entries that have not yet been tested for blame.  leftover
1191         * contains the reversed list of entries that have been tested
1192         * without being assignable to the parent.
1193         */
1194        do {
1195                struct blame_entry **unblamedtail = &unblamed;
1196                struct blame_entry *next;
1197                for (e = unblamed; e; e = next) {
1198                        next = e->next;
1199                        find_copy_in_blob(sb, e, parent, split, &file_p);
1200                        if (split[1].suspect &&
1201                            sb->move_score < blame_entry_score(sb, &split[1])) {
1202                                split_blame(blamed, &unblamedtail, split, e);
1203                        } else {
1204                                e->next = leftover;
1205                                leftover = e;
1206                        }
1207                        decref_split(split);
1208                }
1209                *unblamedtail = NULL;
1210                toosmall = filter_small(sb, toosmall, &unblamed, sb->move_score);
1211        } while (unblamed);
1212        target->suspects = reverse_blame(leftover, NULL);
1213}
1214
1215struct blame_list {
1216        struct blame_entry *ent;
1217        struct blame_entry split[3];
1218};
1219
1220/*
1221 * Count the number of entries the target is suspected for,
1222 * and prepare a list of entry and the best split.
1223 */
1224static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
1225                                           int *num_ents_p)
1226{
1227        struct blame_entry *e;
1228        int num_ents, i;
1229        struct blame_list *blame_list = NULL;
1230
1231        for (e = unblamed, num_ents = 0; e; e = e->next)
1232                num_ents++;
1233        if (num_ents) {
1234                blame_list = xcalloc(num_ents, sizeof(struct blame_list));
1235                for (e = unblamed, i = 0; e; e = e->next)
1236                        blame_list[i++].ent = e;
1237        }
1238        *num_ents_p = num_ents;
1239        return blame_list;
1240}
1241
1242/*
1243 * For lines target is suspected for, see if we can find code movement
1244 * across file boundary from the parent commit.  porigin is the path
1245 * in the parent we already tried.
1246 */
1247static void find_copy_in_parent(struct blame_scoreboard *sb,
1248                                struct blame_entry ***blamed,
1249                                struct blame_entry **toosmall,
1250                                struct blame_origin *target,
1251                                struct commit *parent,
1252                                struct blame_origin *porigin,
1253                                int opt)
1254{
1255        struct diff_options diff_opts;
1256        int i, j;
1257        struct blame_list *blame_list;
1258        int num_ents;
1259        struct blame_entry *unblamed = target->suspects;
1260        struct blame_entry *leftover = NULL;
1261
1262        if (!unblamed)
1263                return; /* nothing remains for this target */
1264
1265        repo_diff_setup(sb->repo, &diff_opts);
1266        diff_opts.flags.recursive = 1;
1267        diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1268
1269        diff_setup_done(&diff_opts);
1270
1271        /* Try "find copies harder" on new path if requested;
1272         * we do not want to use diffcore_rename() actually to
1273         * match things up; find_copies_harder is set only to
1274         * force diff_tree_oid() to feed all filepairs to diff_queue,
1275         * and this code needs to be after diff_setup_done(), which
1276         * usually makes find-copies-harder imply copy detection.
1277         */
1278        if ((opt & PICKAXE_BLAME_COPY_HARDEST)
1279            || ((opt & PICKAXE_BLAME_COPY_HARDER)
1280                && (!porigin || strcmp(target->path, porigin->path))))
1281                diff_opts.flags.find_copies_harder = 1;
1282
1283        if (is_null_oid(&target->commit->object.oid))
1284                do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
1285        else
1286                diff_tree_oid(get_commit_tree_oid(parent),
1287                              get_commit_tree_oid(target->commit),
1288                              "", &diff_opts);
1289
1290        if (!diff_opts.flags.find_copies_harder)
1291                diffcore_std(&diff_opts);
1292
1293        do {
1294                struct blame_entry **unblamedtail = &unblamed;
1295                blame_list = setup_blame_list(unblamed, &num_ents);
1296
1297                for (i = 0; i < diff_queued_diff.nr; i++) {
1298                        struct diff_filepair *p = diff_queued_diff.queue[i];
1299                        struct blame_origin *norigin;
1300                        mmfile_t file_p;
1301                        struct blame_entry potential[3];
1302
1303                        if (!DIFF_FILE_VALID(p->one))
1304                                continue; /* does not exist in parent */
1305                        if (S_ISGITLINK(p->one->mode))
1306                                continue; /* ignore git links */
1307                        if (porigin && !strcmp(p->one->path, porigin->path))
1308                                /* find_move already dealt with this path */
1309                                continue;
1310
1311                        norigin = get_origin(parent, p->one->path);
1312                        oidcpy(&norigin->blob_oid, &p->one->oid);
1313                        norigin->mode = p->one->mode;
1314                        fill_origin_blob(&sb->revs->diffopt, norigin, &file_p, &sb->num_read_blob);
1315                        if (!file_p.ptr)
1316                                continue;
1317
1318                        for (j = 0; j < num_ents; j++) {
1319                                find_copy_in_blob(sb, blame_list[j].ent,
1320                                                  norigin, potential, &file_p);
1321                                copy_split_if_better(sb, blame_list[j].split,
1322                                                     potential);
1323                                decref_split(potential);
1324                        }
1325                        blame_origin_decref(norigin);
1326                }
1327
1328                for (j = 0; j < num_ents; j++) {
1329                        struct blame_entry *split = blame_list[j].split;
1330                        if (split[1].suspect &&
1331                            sb->copy_score < blame_entry_score(sb, &split[1])) {
1332                                split_blame(blamed, &unblamedtail, split,
1333                                            blame_list[j].ent);
1334                        } else {
1335                                blame_list[j].ent->next = leftover;
1336                                leftover = blame_list[j].ent;
1337                        }
1338                        decref_split(split);
1339                }
1340                free(blame_list);
1341                *unblamedtail = NULL;
1342                toosmall = filter_small(sb, toosmall, &unblamed, sb->copy_score);
1343        } while (unblamed);
1344        target->suspects = reverse_blame(leftover, NULL);
1345        diff_flush(&diff_opts);
1346        clear_pathspec(&diff_opts.pathspec);
1347}
1348
1349/*
1350 * The blobs of origin and porigin exactly match, so everything
1351 * origin is suspected for can be blamed on the parent.
1352 */
1353static void pass_whole_blame(struct blame_scoreboard *sb,
1354                             struct blame_origin *origin, struct blame_origin *porigin)
1355{
1356        struct blame_entry *e, *suspects;
1357
1358        if (!porigin->file.ptr && origin->file.ptr) {
1359                /* Steal its file */
1360                porigin->file = origin->file;
1361                origin->file.ptr = NULL;
1362        }
1363        suspects = origin->suspects;
1364        origin->suspects = NULL;
1365        for (e = suspects; e; e = e->next) {
1366                blame_origin_incref(porigin);
1367                blame_origin_decref(e->suspect);
1368                e->suspect = porigin;
1369        }
1370        queue_blames(sb, porigin, suspects);
1371}
1372
1373/*
1374 * We pass blame from the current commit to its parents.  We keep saying
1375 * "parent" (and "porigin"), but what we mean is to find scapegoat to
1376 * exonerate ourselves.
1377 */
1378static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit,
1379                                        int reverse)
1380{
1381        if (!reverse) {
1382                if (revs->first_parent_only &&
1383                    commit->parents &&
1384                    commit->parents->next) {
1385                        free_commit_list(commit->parents->next);
1386                        commit->parents->next = NULL;
1387                }
1388                return commit->parents;
1389        }
1390        return lookup_decoration(&revs->children, &commit->object);
1391}
1392
1393static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reverse)
1394{
1395        struct commit_list *l = first_scapegoat(revs, commit, reverse);
1396        return commit_list_count(l);
1397}
1398
1399/* Distribute collected unsorted blames to the respected sorted lists
1400 * in the various origins.
1401 */
1402static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
1403{
1404        blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
1405                                 compare_blame_suspect);
1406        while (blamed)
1407        {
1408                struct blame_origin *porigin = blamed->suspect;
1409                struct blame_entry *suspects = NULL;
1410                do {
1411                        struct blame_entry *next = blamed->next;
1412                        blamed->next = suspects;
1413                        suspects = blamed;
1414                        blamed = next;
1415                } while (blamed && blamed->suspect == porigin);
1416                suspects = reverse_blame(suspects, NULL);
1417                queue_blames(sb, porigin, suspects);
1418        }
1419}
1420
1421#define MAXSG 16
1422
1423static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt)
1424{
1425        struct rev_info *revs = sb->revs;
1426        int i, pass, num_sg;
1427        struct commit *commit = origin->commit;
1428        struct commit_list *sg;
1429        struct blame_origin *sg_buf[MAXSG];
1430        struct blame_origin *porigin, **sg_origin = sg_buf;
1431        struct blame_entry *toosmall = NULL;
1432        struct blame_entry *blames, **blametail = &blames;
1433
1434        num_sg = num_scapegoats(revs, commit, sb->reverse);
1435        if (!num_sg)
1436                goto finish;
1437        else if (num_sg < ARRAY_SIZE(sg_buf))
1438                memset(sg_buf, 0, sizeof(sg_buf));
1439        else
1440                sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
1441
1442        /*
1443         * The first pass looks for unrenamed path to optimize for
1444         * common cases, then we look for renames in the second pass.
1445         */
1446        for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) {
1447                struct blame_origin *(*find)(struct repository *, struct commit *, struct blame_origin *);
1448                find = pass ? find_rename : find_origin;
1449
1450                for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1451                     i < num_sg && sg;
1452                     sg = sg->next, i++) {
1453                        struct commit *p = sg->item;
1454                        int j, same;
1455
1456                        if (sg_origin[i])
1457                                continue;
1458                        if (parse_commit(p))
1459                                continue;
1460                        porigin = find(sb->repo, p, origin);
1461                        if (!porigin)
1462                                continue;
1463                        if (oideq(&porigin->blob_oid, &origin->blob_oid)) {
1464                                pass_whole_blame(sb, origin, porigin);
1465                                blame_origin_decref(porigin);
1466                                goto finish;
1467                        }
1468                        for (j = same = 0; j < i; j++)
1469                                if (sg_origin[j] &&
1470                                    oideq(&sg_origin[j]->blob_oid, &porigin->blob_oid)) {
1471                                        same = 1;
1472                                        break;
1473                                }
1474                        if (!same)
1475                                sg_origin[i] = porigin;
1476                        else
1477                                blame_origin_decref(porigin);
1478                }
1479        }
1480
1481        sb->num_commits++;
1482        for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1483             i < num_sg && sg;
1484             sg = sg->next, i++) {
1485                struct blame_origin *porigin = sg_origin[i];
1486                if (!porigin)
1487                        continue;
1488                if (!origin->previous) {
1489                        blame_origin_incref(porigin);
1490                        origin->previous = porigin;
1491                }
1492                pass_blame_to_parent(sb, origin, porigin);
1493                if (!origin->suspects)
1494                        goto finish;
1495        }
1496
1497        /*
1498         * Optionally find moves in parents' files.
1499         */
1500        if (opt & PICKAXE_BLAME_MOVE) {
1501                filter_small(sb, &toosmall, &origin->suspects, sb->move_score);
1502                if (origin->suspects) {
1503                        for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1504                             i < num_sg && sg;
1505                             sg = sg->next, i++) {
1506                                struct blame_origin *porigin = sg_origin[i];
1507                                if (!porigin)
1508                                        continue;
1509                                find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
1510                                if (!origin->suspects)
1511                                        break;
1512                        }
1513                }
1514        }
1515
1516        /*
1517         * Optionally find copies from parents' files.
1518         */
1519        if (opt & PICKAXE_BLAME_COPY) {
1520                if (sb->copy_score > sb->move_score)
1521                        filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
1522                else if (sb->copy_score < sb->move_score) {
1523                        origin->suspects = blame_merge(origin->suspects, toosmall);
1524                        toosmall = NULL;
1525                        filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
1526                }
1527                if (!origin->suspects)
1528                        goto finish;
1529
1530                for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1531                     i < num_sg && sg;
1532                     sg = sg->next, i++) {
1533                        struct blame_origin *porigin = sg_origin[i];
1534                        find_copy_in_parent(sb, &blametail, &toosmall,
1535                                            origin, sg->item, porigin, opt);
1536                        if (!origin->suspects)
1537                                goto finish;
1538                }
1539        }
1540
1541finish:
1542        *blametail = NULL;
1543        distribute_blame(sb, blames);
1544        /*
1545         * prepend toosmall to origin->suspects
1546         *
1547         * There is no point in sorting: this ends up on a big
1548         * unsorted list in the caller anyway.
1549         */
1550        if (toosmall) {
1551                struct blame_entry **tail = &toosmall;
1552                while (*tail)
1553                        tail = &(*tail)->next;
1554                *tail = origin->suspects;
1555                origin->suspects = toosmall;
1556        }
1557        for (i = 0; i < num_sg; i++) {
1558                if (sg_origin[i]) {
1559                        drop_origin_blob(sg_origin[i]);
1560                        blame_origin_decref(sg_origin[i]);
1561                }
1562        }
1563        drop_origin_blob(origin);
1564        if (sg_buf != sg_origin)
1565                free(sg_origin);
1566}
1567
1568/*
1569 * The main loop -- while we have blobs with lines whose true origin
1570 * is still unknown, pick one blob, and allow its lines to pass blames
1571 * to its parents. */
1572void assign_blame(struct blame_scoreboard *sb, int opt)
1573{
1574        struct rev_info *revs = sb->revs;
1575        struct commit *commit = prio_queue_get(&sb->commits);
1576
1577        while (commit) {
1578                struct blame_entry *ent;
1579                struct blame_origin *suspect = get_blame_suspects(commit);
1580
1581                /* find one suspect to break down */
1582                while (suspect && !suspect->suspects)
1583                        suspect = suspect->next;
1584
1585                if (!suspect) {
1586                        commit = prio_queue_get(&sb->commits);
1587                        continue;
1588                }
1589
1590                assert(commit == suspect->commit);
1591
1592                /*
1593                 * We will use this suspect later in the loop,
1594                 * so hold onto it in the meantime.
1595                 */
1596                blame_origin_incref(suspect);
1597                parse_commit(commit);
1598                if (sb->reverse ||
1599                    (!(commit->object.flags & UNINTERESTING) &&
1600                     !(revs->max_age != -1 && commit->date < revs->max_age)))
1601                        pass_blame(sb, suspect, opt);
1602                else {
1603                        commit->object.flags |= UNINTERESTING;
1604                        if (commit->object.parsed)
1605                                mark_parents_uninteresting(commit);
1606                }
1607                /* treat root commit as boundary */
1608                if (!commit->parents && !sb->show_root)
1609                        commit->object.flags |= UNINTERESTING;
1610
1611                /* Take responsibility for the remaining entries */
1612                ent = suspect->suspects;
1613                if (ent) {
1614                        suspect->guilty = 1;
1615                        for (;;) {
1616                                struct blame_entry *next = ent->next;
1617                                if (sb->found_guilty_entry)
1618                                        sb->found_guilty_entry(ent, sb->found_guilty_entry_data);
1619                                if (next) {
1620                                        ent = next;
1621                                        continue;
1622                                }
1623                                ent->next = sb->ent;
1624                                sb->ent = suspect->suspects;
1625                                suspect->suspects = NULL;
1626                                break;
1627                        }
1628                }
1629                blame_origin_decref(suspect);
1630
1631                if (sb->debug) /* sanity */
1632                        sanity_check_refcnt(sb);
1633        }
1634}
1635
1636static const char *get_next_line(const char *start, const char *end)
1637{
1638        const char *nl = memchr(start, '\n', end - start);
1639        return nl ? nl + 1 : end;
1640}
1641
1642/*
1643 * To allow quick access to the contents of nth line in the
1644 * final image, prepare an index in the scoreboard.
1645 */
1646static int prepare_lines(struct blame_scoreboard *sb)
1647{
1648        const char *buf = sb->final_buf;
1649        unsigned long len = sb->final_buf_size;
1650        const char *end = buf + len;
1651        const char *p;
1652        int *lineno;
1653        int num = 0;
1654
1655        for (p = buf; p < end; p = get_next_line(p, end))
1656                num++;
1657
1658        ALLOC_ARRAY(sb->lineno, num + 1);
1659        lineno = sb->lineno;
1660
1661        for (p = buf; p < end; p = get_next_line(p, end))
1662                *lineno++ = p - buf;
1663
1664        *lineno = len;
1665
1666        sb->num_lines = num;
1667        return sb->num_lines;
1668}
1669
1670static struct commit *find_single_final(struct rev_info *revs,
1671                                        const char **name_p)
1672{
1673        int i;
1674        struct commit *found = NULL;
1675        const char *name = NULL;
1676
1677        for (i = 0; i < revs->pending.nr; i++) {
1678                struct object *obj = revs->pending.objects[i].item;
1679                if (obj->flags & UNINTERESTING)
1680                        continue;
1681                obj = deref_tag(the_repository, obj, NULL, 0);
1682                if (obj->type != OBJ_COMMIT)
1683                        die("Non commit %s?", revs->pending.objects[i].name);
1684                if (found)
1685                        die("More than one commit to dig from %s and %s?",
1686                            revs->pending.objects[i].name, name);
1687                found = (struct commit *)obj;
1688                name = revs->pending.objects[i].name;
1689        }
1690        if (name_p)
1691                *name_p = xstrdup_or_null(name);
1692        return found;
1693}
1694
1695static struct commit *dwim_reverse_initial(struct rev_info *revs,
1696                                           const char **name_p)
1697{
1698        /*
1699         * DWIM "git blame --reverse ONE -- PATH" as
1700         * "git blame --reverse ONE..HEAD -- PATH" but only do so
1701         * when it makes sense.
1702         */
1703        struct object *obj;
1704        struct commit *head_commit;
1705        struct object_id head_oid;
1706
1707        if (revs->pending.nr != 1)
1708                return NULL;
1709
1710        /* Is that sole rev a committish? */
1711        obj = revs->pending.objects[0].item;
1712        obj = deref_tag(the_repository, obj, NULL, 0);
1713        if (obj->type != OBJ_COMMIT)
1714                return NULL;
1715
1716        /* Do we have HEAD? */
1717        if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
1718                return NULL;
1719        head_commit = lookup_commit_reference_gently(the_repository,
1720                                                     &head_oid, 1);
1721        if (!head_commit)
1722                return NULL;
1723
1724        /* Turn "ONE" into "ONE..HEAD" then */
1725        obj->flags |= UNINTERESTING;
1726        add_pending_object(revs, &head_commit->object, "HEAD");
1727
1728        if (name_p)
1729                *name_p = revs->pending.objects[0].name;
1730        return (struct commit *)obj;
1731}
1732
1733static struct commit *find_single_initial(struct rev_info *revs,
1734                                          const char **name_p)
1735{
1736        int i;
1737        struct commit *found = NULL;
1738        const char *name = NULL;
1739
1740        /*
1741         * There must be one and only one negative commit, and it must be
1742         * the boundary.
1743         */
1744        for (i = 0; i < revs->pending.nr; i++) {
1745                struct object *obj = revs->pending.objects[i].item;
1746                if (!(obj->flags & UNINTERESTING))
1747                        continue;
1748                obj = deref_tag(the_repository, obj, NULL, 0);
1749                if (obj->type != OBJ_COMMIT)
1750                        die("Non commit %s?", revs->pending.objects[i].name);
1751                if (found)
1752                        die("More than one commit to dig up from, %s and %s?",
1753                            revs->pending.objects[i].name, name);
1754                found = (struct commit *) obj;
1755                name = revs->pending.objects[i].name;
1756        }
1757
1758        if (!name)
1759                found = dwim_reverse_initial(revs, &name);
1760        if (!name)
1761                die("No commit to dig up from?");
1762
1763        if (name_p)
1764                *name_p = xstrdup(name);
1765        return found;
1766}
1767
1768void init_scoreboard(struct blame_scoreboard *sb)
1769{
1770        memset(sb, 0, sizeof(struct blame_scoreboard));
1771        sb->move_score = BLAME_DEFAULT_MOVE_SCORE;
1772        sb->copy_score = BLAME_DEFAULT_COPY_SCORE;
1773}
1774
1775void setup_scoreboard(struct blame_scoreboard *sb,
1776                      const char *path,
1777                      struct blame_origin **orig)
1778{
1779        const char *final_commit_name = NULL;
1780        struct blame_origin *o;
1781        struct commit *final_commit = NULL;
1782        enum object_type type;
1783
1784        init_blame_suspects(&blame_suspects);
1785
1786        if (sb->reverse && sb->contents_from)
1787                die(_("--contents and --reverse do not blend well."));
1788
1789        if (!sb->repo)
1790                BUG("repo is NULL");
1791
1792        if (!sb->reverse) {
1793                sb->final = find_single_final(sb->revs, &final_commit_name);
1794                sb->commits.compare = compare_commits_by_commit_date;
1795        } else {
1796                sb->final = find_single_initial(sb->revs, &final_commit_name);
1797                sb->commits.compare = compare_commits_by_reverse_commit_date;
1798        }
1799
1800        if (sb->final && sb->contents_from)
1801                die(_("cannot use --contents with final commit object name"));
1802
1803        if (sb->reverse && sb->revs->first_parent_only)
1804                sb->revs->children.name = NULL;
1805
1806        if (!sb->final) {
1807                /*
1808                 * "--not A B -- path" without anything positive;
1809                 * do not default to HEAD, but use the working tree
1810                 * or "--contents".
1811                 */
1812                setup_work_tree();
1813                sb->final = fake_working_tree_commit(sb->repo,
1814                                                     &sb->revs->diffopt,
1815                                                     path, sb->contents_from);
1816                add_pending_object(sb->revs, &(sb->final->object), ":");
1817        }
1818
1819        if (sb->reverse && sb->revs->first_parent_only) {
1820                final_commit = find_single_final(sb->revs, NULL);
1821                if (!final_commit)
1822                        die(_("--reverse and --first-parent together require specified latest commit"));
1823        }
1824
1825        /*
1826         * If we have bottom, this will mark the ancestors of the
1827         * bottom commits we would reach while traversing as
1828         * uninteresting.
1829         */
1830        if (prepare_revision_walk(sb->revs))
1831                die(_("revision walk setup failed"));
1832
1833        if (sb->reverse && sb->revs->first_parent_only) {
1834                struct commit *c = final_commit;
1835
1836                sb->revs->children.name = "children";
1837                while (c->parents &&
1838                       !oideq(&c->object.oid, &sb->final->object.oid)) {
1839                        struct commit_list *l = xcalloc(1, sizeof(*l));
1840
1841                        l->item = c;
1842                        if (add_decoration(&sb->revs->children,
1843                                           &c->parents->item->object, l))
1844                                BUG("not unique item in first-parent chain");
1845                        c = c->parents->item;
1846                }
1847
1848                if (!oideq(&c->object.oid, &sb->final->object.oid))
1849                        die(_("--reverse --first-parent together require range along first-parent chain"));
1850        }
1851
1852        if (is_null_oid(&sb->final->object.oid)) {
1853                o = get_blame_suspects(sb->final);
1854                sb->final_buf = xmemdupz(o->file.ptr, o->file.size);
1855                sb->final_buf_size = o->file.size;
1856        }
1857        else {
1858                o = get_origin(sb->final, path);
1859                if (fill_blob_sha1_and_mode(sb->repo, o))
1860                        die(_("no such path %s in %s"), path, final_commit_name);
1861
1862                if (sb->revs->diffopt.flags.allow_textconv &&
1863                    textconv_object(sb->repo, path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf,
1864                                    &sb->final_buf_size))
1865                        ;
1866                else
1867                        sb->final_buf = read_object_file(&o->blob_oid, &type,
1868                                                         &sb->final_buf_size);
1869
1870                if (!sb->final_buf)
1871                        die(_("cannot read blob %s for path %s"),
1872                            oid_to_hex(&o->blob_oid),
1873                            path);
1874        }
1875        sb->num_read_blob++;
1876        prepare_lines(sb);
1877
1878        if (orig)
1879                *orig = o;
1880
1881        free((char *)final_commit_name);
1882}
1883
1884
1885
1886struct blame_entry *blame_entry_prepend(struct blame_entry *head,
1887                                        long start, long end,
1888                                        struct blame_origin *o)
1889{
1890        struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry));
1891        new_head->lno = start;
1892        new_head->num_lines = end - start;
1893        new_head->suspect = o;
1894        new_head->s_lno = start;
1895        new_head->next = head;
1896        blame_origin_incref(o);
1897        return new_head;
1898}