git.oblomov.eu Git - git/blob - line-log.c

   1 #include "git-compat-util.h"
   2 #include "line-range.h"
   3 #include "cache.h"
   4 #include "tag.h"
   5 #include "blob.h"
   6 #include "tree.h"
   7 #include "diff.h"
   8 #include "commit.h"
   9 #include "decorate.h"
  10 #include "revision.h"
  11 #include "xdiff-interface.h"
  12 #include "strbuf.h"
  13 #include "log-tree.h"
  14 #include "graph.h"
  15 #include "line-log.h"
  16
  17 static void range_set_grow(struct range_set *rs, size_t extra)
  18 {
  19         ALLOC_GROW(rs->ranges, rs->nr + extra, rs->alloc);
  20 }
  21
  22 /* Either initialization would be fine */
  23 #define RANGE_SET_INIT {0}
  24
  25 static void range_set_init(struct range_set *rs, size_t prealloc)
  26 {
  27         rs->alloc = rs->nr = 0;
  28         rs->ranges = NULL;
  29         if (prealloc)
  30                 range_set_grow(rs, prealloc);
  31 }
  32
  33 static void range_set_release(struct range_set *rs)
  34 {
  35         free(rs->ranges);
  36         rs->alloc = rs->nr = 0;
  37         rs->ranges = NULL;
  38 }
  39
  40 /* dst must be uninitialized! */
  41 static void range_set_copy(struct range_set *dst, struct range_set *src)
  42 {
  43         range_set_init(dst, src->nr);
  44         memcpy(dst->ranges, src->ranges, src->nr*sizeof(struct range_set));
  45         dst->nr = src->nr;
  46 }
  47 static void range_set_move(struct range_set *dst, struct range_set *src)
  48 {
  49         range_set_release(dst);
  50         dst->ranges = src->ranges;
  51         dst->nr = src->nr;
  52         dst->alloc = src->alloc;
  53         src->ranges = NULL;
  54         src->alloc = src->nr = 0;
  55 }
  56
  57 /* tack on a _new_ range _at the end_ */
  58 static void range_set_append(struct range_set *rs, long a, long b)
  59 {
  60         assert(a <= b);
  61         assert(rs->nr == 0 || rs->ranges[rs->nr-1].end <= a);
  62         range_set_grow(rs, 1);
  63         rs->ranges[rs->nr].start = a;
  64         rs->ranges[rs->nr].end = b;
  65         rs->nr++;
  66 }
  67
  68 static int range_cmp(const void *_r, const void *_s)
  69 {
  70         const struct range *r = _r;
  71         const struct range *s = _s;
  72
  73         /* this could be simply 'return r.start-s.start', but for the types */
  74         if (r->start == s->start)
  75                 return 0;
  76         if (r->start < s->start)
  77                 return -1;
  78         return 1;
  79 }
  80
  81 /*
  82  * Helper: In-place pass of sorting and merging the ranges in the
  83  * range set, to re-establish the invariants after another operation
  84  *
  85  * NEEDSWORK currently not needed
  86  */
  87 static void sort_and_merge_range_set(struct range_set *rs)
  88 {
  89         int i;
  90         int o = 1; /* output cursor */
  91
  92         qsort(rs->ranges, rs->nr, sizeof(struct range), range_cmp);
  93
  94         for (i = 1; i < rs->nr; i++) {
  95                 if (rs->ranges[i].start <= rs->ranges[o-1].end) {
  96                         rs->ranges[o-1].end = rs->ranges[i].end;
  97                 } else {
  98                         rs->ranges[o].start = rs->ranges[i].start;
  99                         rs->ranges[o].end = rs->ranges[i].end;
 100                         o++;
 101                 }
 102         }
 103         assert(o <= rs->nr);
 104         rs->nr = o;
 105 }
 106
 107 /*
 108  * Union of range sets (i.e., sets of line numbers).  Used to merge
 109  * them when searches meet at a common ancestor.
 110  *
 111  * This is also where the ranges are consolidated into canonical form:
 112  * overlapping and adjacent ranges are merged, and empty ranges are
 113  * removed.
 114  */
 115 static void range_set_union(struct range_set *out,
 116                              struct range_set *a, struct range_set *b)
 117 {
 118         int i = 0, j = 0, o = 0;
 119         struct range *ra = a->ranges;
 120         struct range *rb = b->ranges;
 121         /* cannot make an alias of out->ranges: it may change during grow */
 122
 123         assert(out->nr == 0);
 124         while (i < a->nr || j < b->nr) {
 125                 struct range *new;
 126                 if (i < a->nr && j < b->nr) {
 127                         if (ra[i].start < rb[j].start)
 128                                 new = &ra[i++];
 129                         else if (ra[i].start > rb[j].start)
 130                                 new = &rb[j++];
 131                         else if (ra[i].end < rb[j].end)
 132                                 new = &ra[i++];
 133                         else
 134                                 new = &rb[j++];
 135                 } else if (i < a->nr)      /* b exhausted */
 136                         new = &ra[i++];
 137                 else                       /* a exhausted */
 138                         new = &rb[j++];
 139                 if (new->start == new->end)
 140                         ; /* empty range */
 141                 else if (!o || out->ranges[o-1].end < new->start) {
 142                         range_set_grow(out, 1);
 143                         out->ranges[o].start = new->start;
 144                         out->ranges[o].end = new->end;
 145                         o++;
 146                 } else if (out->ranges[o-1].end < new->end) {
 147                         out->ranges[o-1].end = new->end;
 148                 }
 149         }
 150         out->nr = o;
 151 }
 152
 153 /*
 154  * Difference of range sets (out = a \ b).  Pass the "interesting"
 155  * ranges as 'a' and the target side of the diff as 'b': it removes
 156  * the ranges for which the commit is responsible.
 157  */
 158 static void range_set_difference(struct range_set *out,
 159                                   struct range_set *a, struct range_set *b)
 160 {
 161         int i, j =  0;
 162         for (i = 0; i < a->nr; i++) {
 163                 long start = a->ranges[i].start;
 164                 long end = a->ranges[i].end;
 165                 while (start < end) {
 166                         while (j < b->nr && start >= b->ranges[j].end)
 167                                 /*
 168                                  * a:         |-------
 169                                  * b: ------|
 170                                  */
 171                                 j++;
 172                         if (j >= b->nr || end < b->ranges[j].start) {
 173                                 /*
 174                                  * b exhausted, or
 175                                  * a:  ----|
 176                                  * b:         |----
 177                                  */
 178                                 range_set_append(out, start, end);
 179                                 break;
 180                         }
 181                         if (start >= b->ranges[j].start) {
 182                                 /*
 183                                  * a:     |--????
 184                                  * b: |------|
 185                                  */
 186                                 start = b->ranges[j].end;
 187                         } else if (end > b->ranges[j].start) {
 188                                 /*
 189                                  * a: |-----|
 190                                  * b:    |--?????
 191                                  */
 192                                 if (start < b->ranges[j].start)
 193                                         range_set_append(out, start, b->ranges[j].start);
 194                                 start = b->ranges[j].end;
 195                         }
 196                 }
 197         }
 198 }
 199
 200 static void diff_ranges_init(struct diff_ranges *diff)
 201 {
 202         range_set_init(&diff->parent, 0);
 203         range_set_init(&diff->target, 0);
 204 }
 205
 206 static void diff_ranges_release(struct diff_ranges *diff)
 207 {
 208         range_set_release(&diff->parent);
 209         range_set_release(&diff->target);
 210 }
 211
 212 void line_log_data_init(struct line_log_data *r)
 213 {
 214         memset(r, 0, sizeof(struct line_log_data));
 215         range_set_init(&r->ranges, 0);
 216 }
 217
 218 static void line_log_data_clear(struct line_log_data *r)
 219 {
 220         range_set_release(&r->ranges);
 221         if (r->pair)
 222                 diff_free_filepair(r->pair);
 223 }
 224
 225 static void free_line_log_data(struct line_log_data *r)
 226 {
 227         while (r) {
 228                 struct line_log_data *next = r->next;
 229                 line_log_data_clear(r);
 230                 free(r);
 231                 r = next;
 232         }
 233 }
 234
 235 static struct line_log_data *
 236 search_line_log_data(struct line_log_data *list, const char *path,
 237                      struct line_log_data **insertion_point)
 238 {
 239         struct line_log_data *p = list;
 240         if (insertion_point)
 241                 *insertion_point = NULL;
 242         while (p) {
 243                 int cmp = strcmp(p->spec->path, path);
 244                 if (!cmp)
 245                         return p;
 246                 if (insertion_point && cmp < 0)
 247                         *insertion_point = p;
 248                 p = p->next;
 249         }
 250         return NULL;
 251 }
 252
 253 static void line_log_data_insert(struct line_log_data **list,
 254                                  struct diff_filespec *spec,
 255                                  long begin, long end)
 256 {
 257         struct line_log_data *ip;
 258         struct line_log_data *p = search_line_log_data(*list, spec->path, &ip);
 259
 260         if (p) {
 261                 range_set_append(&p->ranges, begin, end);
 262                 sort_and_merge_range_set(&p->ranges);
 263                 free_filespec(spec);
 264                 return;
 265         }
 266
 267         p = xcalloc(1, sizeof(struct line_log_data));
 268         p->spec = spec;
 269         range_set_append(&p->ranges, begin, end);
 270         if (ip) {
 271                 p->next = ip->next;
 272                 ip->next = p;
 273         } else {
 274                 p->next = *list;
 275                 *list = p;
 276         }
 277 }
 278
 279 struct collect_diff_cbdata {
 280         struct diff_ranges *diff;
 281 };
 282
 283 static int collect_diff_cb(long start_a, long count_a,
 284                            long start_b, long count_b,
 285                            void *data)
 286 {
 287         struct collect_diff_cbdata *d = data;
 288
 289         if (count_a >= 0)
 290                 range_set_append(&d->diff->parent, start_a, start_a + count_a);
 291         if (count_b >= 0)
 292                 range_set_append(&d->diff->target, start_b, start_b + count_b);
 293
 294         return 0;
 295 }
 296
 297 static void collect_diff(mmfile_t *parent, mmfile_t *target, struct diff_ranges *out)
 298 {
 299         struct collect_diff_cbdata cbdata = {NULL};
 300         xpparam_t xpp;
 301         xdemitconf_t xecfg;
 302         xdemitcb_t ecb;
 303
 304         memset(&xpp, 0, sizeof(xpp));
 305         memset(&xecfg, 0, sizeof(xecfg));
 306         xecfg.ctxlen = xecfg.interhunkctxlen = 0;
 307
 308         cbdata.diff = out;
 309         xecfg.hunk_func = collect_diff_cb;
 310         memset(&ecb, 0, sizeof(ecb));
 311         ecb.priv = &cbdata;
 312         xdi_diff(parent, target, &xpp, &xecfg, &ecb);
 313 }
 314
 315 /*
 316  * These are handy for debugging.  Removing them with #if 0 silences
 317  * the "unused function" warning.
 318  */
 319 #if 0
 320 static void dump_range_set(struct range_set *rs, const char *desc)
 321 {
 322         int i;
 323         printf("range set %s (%d items):\n", desc, rs->nr);
 324         for (i = 0; i < rs->nr; i++)
 325                 printf("\t[%ld,%ld]\n", rs->ranges[i].start, rs->ranges[i].end);
 326 }
 327
 328 static void dump_line_log_data(struct line_log_data *r)
 329 {
 330         char buf[4096];
 331         while (r) {
 332                 snprintf(buf, 4096, "file %s\n", r->spec->path);
 333                 dump_range_set(&r->ranges, buf);
 334                 r = r->next;
 335         }
 336 }
 337
 338 static void dump_diff_ranges(struct diff_ranges *diff, const char *desc)
 339 {
 340         int i;
 341         assert(diff->parent.nr == diff->target.nr);
 342         printf("diff ranges %s (%d items):\n", desc, diff->parent.nr);
 343         printf("\tparent\ttarget\n");
 344         for (i = 0; i < diff->parent.nr; i++) {
 345                 printf("\t[%ld,%ld]\t[%ld,%ld]\n",
 346                        diff->parent.ranges[i].start,
 347                        diff->parent.ranges[i].end,
 348                        diff->target.ranges[i].start,
 349                        diff->target.ranges[i].end);
 350         }
 351 }
 352 #endif
 353
 354
 355 static int ranges_overlap(struct range *a, struct range *b)
 356 {
 357         return !(a->end <= b->start || b->end <= a->start);
 358 }
 359
 360 /*
 361  * Given a diff and the set of interesting ranges, determine all hunks
 362  * of the diff which touch (overlap) at least one of the interesting
 363  * ranges in the target.
 364  */
 365 static void diff_ranges_filter_touched(struct diff_ranges *out,
 366                                        struct diff_ranges *diff,
 367                                        struct range_set *rs)
 368 {
 369         int i, j = 0;
 370
 371         assert(out->target.nr == 0);
 372
 373         for (i = 0; i < diff->target.nr; i++) {
 374                 while (diff->target.ranges[i].start > rs->ranges[j].end) {
 375                         j++;
 376                         if (j == rs->nr)
 377                                 return;
 378                 }
 379                 if (ranges_overlap(&diff->target.ranges[i], &rs->ranges[j])) {
 380                         range_set_append(&out->parent,
 381                                          diff->parent.ranges[i].start,
 382                                          diff->parent.ranges[i].end);
 383                         range_set_append(&out->target,
 384                                          diff->target.ranges[i].start,
 385                                          diff->target.ranges[i].end);
 386                 }
 387         }
 388 }
 389
 390 /*
 391  * Adjust the line counts in 'rs' to account for the lines
 392  * added/removed in the diff.
 393  */
 394 static void range_set_shift_diff(struct range_set *out,
 395                                  struct range_set *rs,
 396                                  struct diff_ranges *diff)
 397 {
 398         int i, j = 0;
 399         long offset = 0;
 400         struct range *src = rs->ranges;
 401         struct range *target = diff->target.ranges;
 402         struct range *parent = diff->parent.ranges;
 403
 404         for (i = 0; i < rs->nr; i++) {
 405                 while (j < diff->target.nr && src[i].start >= target[j].start) {
 406                         offset += (parent[j].end-parent[j].start)
 407                                 - (target[j].end-target[j].start);
 408                         j++;
 409                 }
 410                 range_set_append(out, src[i].start+offset, src[i].end+offset);
 411         }
 412 }
 413
 414 /*
 415  * Given a diff and the set of interesting ranges, map the ranges
 416  * across the diff.  That is: observe that the target commit takes
 417  * blame for all the + (target-side) ranges.  So for every pair of
 418  * ranges in the diff that was touched, we remove the latter and add
 419  * its parent side.
 420  */
 421 static void range_set_map_across_diff(struct range_set *out,
 422                                       struct range_set *rs,
 423                                       struct diff_ranges *diff,
 424                                       struct diff_ranges **touched_out)
 425 {
 426         struct diff_ranges *touched = xmalloc(sizeof(*touched));
 427         struct range_set tmp1 = RANGE_SET_INIT;
 428         struct range_set tmp2 = RANGE_SET_INIT;
 429
 430         diff_ranges_init(touched);
 431         diff_ranges_filter_touched(touched, diff, rs);
 432         range_set_difference(&tmp1, rs, &touched->target);
 433         range_set_shift_diff(&tmp2, &tmp1, diff);
 434         range_set_union(out, &tmp2, &touched->parent);
 435         range_set_release(&tmp1);
 436         range_set_release(&tmp2);
 437
 438         *touched_out = touched;
 439 }
 440
 441
 442 static struct commit *check_single_commit(struct rev_info *revs)
 443 {
 444         struct object *commit = NULL;
 445         int found = -1;
 446         int i;
 447
 448         for (i = 0; i < revs->pending.nr; i++) {
 449                 struct object *obj = revs->pending.objects[i].item;
 450                 if (obj->flags & UNINTERESTING)
 451                         continue;
 452                 while (obj->type == OBJ_TAG)
 453                         obj = deref_tag(obj, NULL, 0);
 454                 if (obj->type != OBJ_COMMIT)
 455                         die("Non commit %s?", revs->pending.objects[i].name);
 456                 if (commit)
 457                         die("More than one commit to dig from: %s and %s?",
 458                             revs->pending.objects[i].name,
 459                             revs->pending.objects[found].name);
 460                 commit = obj;
 461                 found = i;
 462         }
 463
 464         if (!commit)
 465                 die("No commit specified?");
 466
 467         return (struct commit *) commit;
 468 }
 469
 470 static void fill_blob_sha1(struct commit *commit, struct diff_filespec *spec)
 471 {
 472         unsigned mode;
 473         unsigned char sha1[20];
 474
 475         if (get_tree_entry(commit->object.sha1, spec->path,
 476                            sha1, &mode))
 477                 die("There is no path %s in the commit", spec->path);
 478         fill_filespec(spec, sha1, 1, mode);
 479
 480         return;
 481 }
 482
 483 static void fill_line_ends(struct diff_filespec *spec, long *lines,
 484                            unsigned long **line_ends)
 485 {
 486         int num = 0, size = 50;
 487         long cur = 0;
 488         unsigned long *ends = NULL;
 489         char *data = NULL;
 490
 491         if (diff_populate_filespec(spec, 0))
 492                 die("Cannot read blob %s", sha1_to_hex(spec->sha1));
 493
 494         ends = xmalloc(size * sizeof(*ends));
 495         ends[cur++] = 0;
 496         data = spec->data;
 497         while (num < spec->size) {
 498                 if (data[num] == '\n' || num == spec->size - 1) {
 499                         ALLOC_GROW(ends, (cur + 1), size);
 500                         ends[cur++] = num;
 501                 }
 502                 num++;
 503         }
 504
 505         /* shrink the array to fit the elements */
 506         ends = xrealloc(ends, cur * sizeof(*ends));
 507         *lines = cur-1;
 508         *line_ends = ends;
 509 }
 510
 511 struct nth_line_cb {
 512         struct diff_filespec *spec;
 513         long lines;
 514         unsigned long *line_ends;
 515 };
 516
 517 static const char *nth_line(void *data, long line)
 518 {
 519         struct nth_line_cb *d = data;
 520         assert(d && line <= d->lines);
 521         assert(d->spec && d->spec->data);
 522
 523         if (line == 0)
 524                 return (char *)d->spec->data;
 525         else
 526                 return (char *)d->spec->data + d->line_ends[line] + 1;
 527 }
 528
 529 static struct line_log_data *
 530 parse_lines(struct commit *commit, const char *prefix, struct string_list *args)
 531 {
 532         long lines = 0;
 533         unsigned long *ends = NULL;
 534         struct nth_line_cb cb_data;
 535         struct string_list_item *item;
 536         struct line_log_data *ranges = NULL;
 537
 538         for_each_string_list_item(item, args) {
 539                 const char *name_part, *range_part;
 540                 const char *full_name;
 541                 struct diff_filespec *spec;
 542                 long begin = 0, end = 0;
 543
 544                 name_part = skip_range_arg(item->string);
 545                 if (!name_part || *name_part != ':' || !name_part[1])
 546                         die("-L argument '%s' not of the form start,end:file",
 547                             item->string);
 548                 range_part = xstrndup(item->string, name_part - item->string);
 549                 name_part++;
 550
 551                 full_name = prefix_path(prefix, prefix ? strlen(prefix) : 0,
 552                                         name_part);
 553
 554                 spec = alloc_filespec(full_name);
 555                 fill_blob_sha1(commit, spec);
 556                 fill_line_ends(spec, &lines, &ends);
 557                 cb_data.spec = spec;
 558                 cb_data.lines = lines;
 559                 cb_data.line_ends = ends;
 560
 561                 if (parse_range_arg(range_part, nth_line, &cb_data,
 562                                     lines, &begin, &end))
 563                         die("malformed -L argument '%s'", range_part);
 564                 if (begin < 1)
 565                         begin = 1;
 566                 if (end < 1)
 567                         end = lines;
 568                 begin--;
 569                 if (lines < end || lines < begin)
 570                         die("file %s has only %ld lines", name_part, lines);
 571                 line_log_data_insert(&ranges, spec, begin, end);
 572
 573                 free(ends);
 574                 ends = NULL;
 575         }
 576
 577         return ranges;
 578 }
 579
 580 static struct line_log_data *line_log_data_copy_one(struct line_log_data *r)
 581 {
 582         struct line_log_data *ret = xmalloc(sizeof(*ret));
 583
 584         assert(r);
 585         line_log_data_init(ret);
 586         range_set_copy(&ret->ranges, &r->ranges);
 587
 588         ret->spec = r->spec;
 589         assert(ret->spec);
 590         ret->spec->count++;
 591
 592         return ret;
 593 }
 594
 595 static struct line_log_data *
 596 line_log_data_copy(struct line_log_data *r)
 597 {
 598         struct line_log_data *ret = NULL;
 599         struct line_log_data *tmp = NULL, *prev = NULL;
 600
 601         assert(r);
 602         ret = tmp = prev = line_log_data_copy_one(r);
 603         r = r->next;
 604         while (r) {
 605                 tmp = line_log_data_copy_one(r);
 606                 prev->next = tmp;
 607                 prev = tmp;
 608                 r = r->next;
 609         }
 610
 611         return ret;
 612 }
 613
 614 /* merge two range sets across files */
 615 static struct line_log_data *line_log_data_merge(struct line_log_data *a,
 616                                                  struct line_log_data *b)
 617 {
 618         struct line_log_data *head = NULL, **pp = &head;
 619
 620         while (a || b) {
 621                 struct line_log_data *src;
 622                 struct line_log_data *src2 = NULL;
 623                 struct line_log_data *d;
 624                 int cmp;
 625                 if (!a)
 626                         cmp = 1;
 627                 else if (!b)
 628                         cmp = -1;
 629                 else
 630                         cmp = strcmp(a->spec->path, b->spec->path);
 631                 if (cmp < 0) {
 632                         src = a;
 633                         a = a->next;
 634                 } else if (cmp == 0) {
 635                         src = a;
 636                         a = a->next;
 637                         src2 = b;
 638                         b = b->next;
 639                 } else {
 640                         src = b;
 641                         b = b->next;
 642                 }
 643                 d = xmalloc(sizeof(struct line_log_data));
 644                 line_log_data_init(d);
 645                 d->spec = src->spec;
 646                 d->spec->count++;
 647                 *pp = d;
 648                 pp = &d->next;
 649                 if (src2)
 650                         range_set_union(&d->ranges, &src->ranges, &src2->ranges);
 651                 else
 652                         range_set_copy(&d->ranges, &src->ranges);
 653         }
 654
 655         return head;
 656 }
 657
 658 static void add_line_range(struct rev_info *revs, struct commit *commit,
 659                            struct line_log_data *range)
 660 {
 661         struct line_log_data *old = NULL;
 662         struct line_log_data *new = NULL;
 663
 664         old = lookup_decoration(&revs->line_log_data, &commit->object);
 665         if (old && range) {
 666                 new = line_log_data_merge(old, range);
 667                 free_line_log_data(old);
 668         } else if (range)
 669                 new = line_log_data_copy(range);
 670
 671         if (new)
 672                 add_decoration(&revs->line_log_data, &commit->object, new);
 673 }
 674
 675 static void clear_commit_line_range(struct rev_info *revs, struct commit *commit)
 676 {
 677         struct line_log_data *r;
 678         r = lookup_decoration(&revs->line_log_data, &commit->object);
 679         if (!r)
 680                 return;
 681         free_line_log_data(r);
 682         add_decoration(&revs->line_log_data, &commit->object, NULL);
 683 }
 684
 685 static struct line_log_data *lookup_line_range(struct rev_info *revs,
 686                                                struct commit *commit)
 687 {
 688         struct line_log_data *ret = NULL;
 689
 690         ret = lookup_decoration(&revs->line_log_data, &commit->object);
 691         return ret;
 692 }
 693
 694 void line_log_init(struct rev_info *rev, const char *prefix, struct string_list *args)
 695 {
 696         struct commit *commit = NULL;
 697         struct line_log_data *range;
 698
 699         commit = check_single_commit(rev);
 700         range = parse_lines(commit, prefix, args);
 701         add_line_range(rev, commit, range);
 702
 703         if (!rev->diffopt.detect_rename) {
 704                 int i, count = 0;
 705                 struct line_log_data *r = range;
 706                 const char **paths;
 707                 while (r) {
 708                         count++;
 709                         r = r->next;
 710                 }
 711                 paths = xmalloc((count+1)*sizeof(char *));
 712                 r = range;
 713                 for (i = 0; i < count; i++) {
 714                         paths[i] = xstrdup(r->spec->path);
 715                         r = r->next;
 716                 }
 717                 paths[count] = NULL;
 718                 init_pathspec(&rev->diffopt.pathspec, paths);
 719                 free(paths);
 720         }
 721 }
 722
 723 static void load_tree_desc(struct tree_desc *desc, void **tree,
 724                            const unsigned char *sha1)
 725 {
 726         unsigned long size;
 727         *tree = read_object_with_reference(sha1, tree_type, &size, NULL);
 728         if (!*tree)
 729                 die("Unable to read tree (%s)", sha1_to_hex(sha1));
 730         init_tree_desc(desc, *tree, size);
 731 }
 732
 733 static int count_parents(struct commit *commit)
 734 {
 735         struct commit_list *parents = commit->parents;
 736         int count = 0;
 737         while (parents) {
 738                 count++;
 739                 parents = parents->next;
 740         }
 741         return count;
 742 }
 743
 744 static void move_diff_queue(struct diff_queue_struct *dst,
 745                             struct diff_queue_struct *src)
 746 {
 747         assert(src != dst);
 748         memcpy(dst, src, sizeof(struct diff_queue_struct));
 749         DIFF_QUEUE_CLEAR(src);
 750 }
 751
 752 static void queue_diffs(struct diff_options *opt,
 753                         struct diff_queue_struct *queue,
 754                         struct commit *commit, struct commit *parent)
 755 {
 756         void *tree1 = NULL, *tree2 = NULL;
 757         struct tree_desc desc1, desc2;
 758
 759         assert(commit);
 760         load_tree_desc(&desc2, &tree2, commit->tree->object.sha1);
 761         if (parent)
 762                 load_tree_desc(&desc1, &tree1, parent->tree->object.sha1);
 763         else
 764                 init_tree_desc(&desc1, "", 0);
 765
 766         DIFF_QUEUE_CLEAR(&diff_queued_diff);
 767         diff_tree(&desc1, &desc2, "", opt);
 768         diffcore_std(opt);
 769         move_diff_queue(queue, &diff_queued_diff);
 770
 771         if (tree1)
 772                 free(tree1);
 773         if (tree2)
 774                 free(tree2);
 775 }
 776
 777 static char *get_nth_line(long line, unsigned long *ends, void *data)
 778 {
 779         if (line == 0)
 780                 return (char *)data;
 781         else
 782                 return (char *)data + ends[line] + 1;
 783 }
 784
 785 static void print_line(const char *prefix, char first,
 786                        long line, unsigned long *ends, void *data,
 787                        const char *color, const char *reset)
 788 {
 789         char *begin = get_nth_line(line, ends, data);
 790         char *end = get_nth_line(line+1, ends, data);
 791         int had_nl = 0;
 792
 793         if (end > begin && end[-1] == '\n') {
 794                 end--;
 795                 had_nl = 1;
 796         }
 797
 798         fputs(prefix, stdout);
 799         fputs(color, stdout);
 800         putchar(first);
 801         fwrite(begin, 1, end-begin, stdout);
 802         fputs(reset, stdout);
 803         putchar('\n');
 804         if (!had_nl)
 805                 fputs("\\ No newline at end of file\n", stdout);
 806 }
 807
 808 static char *output_prefix(struct diff_options *opt)
 809 {
 810         char *prefix = "";
 811
 812         if (opt->output_prefix) {
 813                 struct strbuf *sb = opt->output_prefix(opt, opt->output_prefix_data);
 814                 prefix = sb->buf;
 815         }
 816
 817         return prefix;
 818 }
 819
 820 static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *range)
 821 {
 822         int i, j = 0;
 823         long p_lines, t_lines;
 824         unsigned long *p_ends = NULL, *t_ends = NULL;
 825         struct diff_filepair *pair = range->pair;
 826         struct diff_ranges *diff = &range->diff;
 827
 828         struct diff_options *opt = &rev->diffopt;
 829         char *prefix = output_prefix(opt);
 830         const char *c_reset = diff_get_color(opt->use_color, DIFF_RESET);
 831         const char *c_frag = diff_get_color(opt->use_color, DIFF_FRAGINFO);
 832         const char *c_meta = diff_get_color(opt->use_color, DIFF_METAINFO);
 833         const char *c_old = diff_get_color(opt->use_color, DIFF_FILE_OLD);
 834         const char *c_new = diff_get_color(opt->use_color, DIFF_FILE_NEW);
 835         const char *c_plain = diff_get_color(opt->use_color, DIFF_PLAIN);
 836
 837         if (!pair || !diff)
 838                 return;
 839
 840         if (pair->one->sha1_valid)
 841                 fill_line_ends(pair->one, &p_lines, &p_ends);
 842         fill_line_ends(pair->two, &t_lines, &t_ends);
 843
 844         printf("%s%sdiff --git a/%s b/%s%s\n", prefix, c_meta, pair->one->path, pair->two->path, c_reset);
 845         printf("%s%s--- %s%s%s\n", prefix, c_meta,
 846                pair->one->sha1_valid ? "a/" : "",
 847                pair->one->sha1_valid ? pair->one->path : "/dev/null",
 848                c_reset);
 849         printf("%s%s+++ b/%s%s\n", prefix, c_meta, pair->two->path, c_reset);
 850         for (i = 0; i < range->ranges.nr; i++) {
 851                 long p_start, p_end;
 852                 long t_start = range->ranges.ranges[i].start;
 853                 long t_end = range->ranges.ranges[i].end;
 854                 long t_cur = t_start;
 855                 int j_last;
 856
 857                 while (j < diff->target.nr && diff->target.ranges[j].end < t_start)
 858                         j++;
 859                 if (j == diff->target.nr || diff->target.ranges[j].start > t_end)
 860                         continue;
 861
 862                 /* Scan ahead to determine the last diff that falls in this range */
 863                 j_last = j;
 864                 while (j_last < diff->target.nr && diff->target.ranges[j_last].start < t_end)
 865                         j_last++;
 866                 if (j_last > j)
 867                         j_last--;
 868
 869                 /*
 870                  * Compute parent hunk headers: we know that the diff
 871                  * has the correct line numbers (but not all hunks).
 872                  * So it suffices to shift the start/end according to
 873                  * the line numbers of the first/last hunk(s) that
 874                  * fall in this range.
 875                  */
 876                 if (t_start < diff->target.ranges[j].start)
 877                         p_start = diff->parent.ranges[j].start - (diff->target.ranges[j].start-t_start);
 878                 else
 879                         p_start = diff->parent.ranges[j].start;
 880                 if (t_end > diff->target.ranges[j_last].end)
 881                         p_end = diff->parent.ranges[j_last].end + (t_end-diff->target.ranges[j_last].end);
 882                 else
 883                         p_end = diff->parent.ranges[j_last].end;
 884
 885                 if (!p_start && !p_end) {
 886                         p_start = -1;
 887                         p_end = -1;
 888                 }
 889
 890                 /* Now output a diff hunk for this range */
 891                 printf("%s%s@@ -%ld,%ld +%ld,%ld @@%s\n",
 892                        prefix, c_frag,
 893                        p_start+1, p_end-p_start, t_start+1, t_end-t_start,
 894                        c_reset);
 895                 while (j < diff->target.nr && diff->target.ranges[j].start < t_end) {
 896                         int k;
 897                         for (; t_cur < diff->target.ranges[j].start; t_cur++)
 898                                 print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
 899                                            c_plain, c_reset);
 900                         for (k = diff->parent.ranges[j].start; k < diff->parent.ranges[j].end; k++)
 901                                 print_line(prefix, '-', k, p_ends, pair->one->data,
 902                                            c_old, c_reset);
 903                         for (; t_cur < diff->target.ranges[j].end && t_cur < t_end; t_cur++)
 904                                 print_line(prefix, '+', t_cur, t_ends, pair->two->data,
 905                                            c_new, c_reset);
 906                         j++;
 907                 }
 908                 for (; t_cur < t_end; t_cur++)
 909                         print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
 910                                    c_plain, c_reset);
 911         }
 912
 913         free(p_ends);
 914         free(t_ends);
 915 }
 916
 917 /*
 918  * NEEDSWORK: manually building a diff here is not the Right
 919  * Thing(tm).  log -L should be built into the diff pipeline.
 920  */
 921 static void dump_diff_hacky(struct rev_info *rev, struct line_log_data *range)
 922 {
 923         puts(output_prefix(&rev->diffopt));
 924         while (range) {
 925                 dump_diff_hacky_one(rev, range);
 926                 range = range->next;
 927         }
 928 }
 929
 930 /*
 931  * Unlike most other functions, this destructively operates on
 932  * 'range'.
 933  */
 934 static int process_diff_filepair(struct rev_info *rev,
 935                                  struct diff_filepair *pair,
 936                                  struct line_log_data *range,
 937                                  struct diff_ranges **diff_out)
 938 {
 939         struct line_log_data *rg = range;
 940         struct range_set tmp;
 941         struct diff_ranges diff;
 942         mmfile_t file_parent, file_target;
 943
 944         assert(pair->two->path);
 945         while (rg) {
 946                 assert(rg->spec->path);
 947                 if (!strcmp(rg->spec->path, pair->two->path))
 948                         break;
 949                 rg = rg->next;
 950         }
 951
 952         if (!rg)
 953                 return 0;
 954         if (rg->ranges.nr == 0)
 955                 return 0;
 956
 957         assert(pair->two->sha1_valid);
 958         diff_populate_filespec(pair->two, 0);
 959         file_target.ptr = pair->two->data;
 960         file_target.size = pair->two->size;
 961
 962         if (pair->one->sha1_valid) {
 963                 diff_populate_filespec(pair->one, 0);
 964                 file_parent.ptr = pair->one->data;
 965                 file_parent.size = pair->one->size;
 966         } else {
 967                 file_parent.ptr = "";
 968                 file_parent.size = 0;
 969         }
 970
 971         diff_ranges_init(&diff);
 972         collect_diff(&file_parent, &file_target, &diff);
 973
 974         /* NEEDSWORK should apply some heuristics to prevent mismatches */
 975         rg->spec->path = xstrdup(pair->one->path);
 976
 977         range_set_init(&tmp, 0);
 978         range_set_map_across_diff(&tmp, &rg->ranges, &diff, diff_out);
 979         range_set_release(&rg->ranges);
 980         range_set_move(&rg->ranges, &tmp);
 981
 982         diff_ranges_release(&diff);
 983
 984         return ((*diff_out)->parent.nr > 0);
 985 }
 986
 987 static struct diff_filepair *diff_filepair_dup(struct diff_filepair *pair)
 988 {
 989         struct diff_filepair *new = xmalloc(sizeof(struct diff_filepair));
 990         new->one = pair->one;
 991         new->two = pair->two;
 992         new->one->count++;
 993         new->two->count++;
 994         return new;
 995 }
 996
 997 static void free_diffqueues(int n, struct diff_queue_struct *dq)
 998 {
 999         int i, j;
1000         for (i = 0; i < n; i++)
1001                 for (j = 0; j < dq[i].nr; j++)
1002                         diff_free_filepair(dq[i].queue[j]);
1003         free(dq);
1004 }
1005
1006 static int process_all_files(struct line_log_data **range_out,
1007                              struct rev_info *rev,
1008                              struct diff_queue_struct *queue,
1009                              struct line_log_data *range)
1010 {
1011         int i, changed = 0;
1012
1013         *range_out = line_log_data_copy(range);
1014
1015         for (i = 0; i < queue->nr; i++) {
1016                 struct diff_ranges *pairdiff = NULL;
1017                 if (process_diff_filepair(rev, queue->queue[i], *range_out, &pairdiff)) {
1018                         struct line_log_data *rg = range;
1019                         changed++;
1020                         /* NEEDSWORK tramples over data structures not owned here */
1021                         while (rg && strcmp(rg->spec->path, queue->queue[i]->two->path))
1022                                 rg = rg->next;
1023                         assert(rg);
1024                         rg->pair = diff_filepair_dup(queue->queue[i]);
1025                         memcpy(&rg->diff, pairdiff, sizeof(struct diff_ranges));
1026                 }
1027         }
1028
1029         return changed;
1030 }
1031
1032 int line_log_print(struct rev_info *rev, struct commit *commit)
1033 {
1034         struct line_log_data *range = lookup_line_range(rev, commit);
1035
1036         show_log(rev);
1037         dump_diff_hacky(rev, range);
1038         return 1;
1039 }
1040
1041 static int process_ranges_ordinary_commit(struct rev_info *rev, struct commit *commit,
1042                                           struct line_log_data *range)
1043 {
1044         struct commit *parent = NULL;
1045         struct diff_queue_struct queue;
1046         struct line_log_data *parent_range;
1047         int changed;
1048
1049         if (commit->parents)
1050                 parent = commit->parents->item;
1051
1052         queue_diffs(&rev->diffopt, &queue, commit, parent);
1053         changed = process_all_files(&parent_range, rev, &queue, range);
1054         if (parent)
1055                 add_line_range(rev, parent, parent_range);
1056         return changed;
1057 }
1058
1059 static int process_ranges_merge_commit(struct rev_info *rev, struct commit *commit,
1060                                        struct line_log_data *range)
1061 {
1062         struct diff_queue_struct *diffqueues;
1063         struct line_log_data **cand;
1064         struct commit **parents;
1065         struct commit_list *p;
1066         int i;
1067         int nparents = count_parents(commit);
1068
1069         diffqueues = xmalloc(nparents * sizeof(*diffqueues));
1070         cand = xmalloc(nparents * sizeof(*cand));
1071         parents = xmalloc(nparents * sizeof(*parents));
1072
1073         p = commit->parents;
1074         for (i = 0; i < nparents; i++) {
1075                 parents[i] = p->item;
1076                 p = p->next;
1077                 queue_diffs(&rev->diffopt, &diffqueues[i], commit, parents[i]);
1078         }
1079
1080         for (i = 0; i < nparents; i++) {
1081                 int changed;
1082                 cand[i] = NULL;
1083                 changed = process_all_files(&cand[i], rev, &diffqueues[i], range);
1084                 if (!changed) {
1085                         /*
1086                          * This parent can take all the blame, so we
1087                          * don't follow any other path in history
1088                          */
1089                         add_line_range(rev, parents[i], cand[i]);
1090                         clear_commit_line_range(rev, commit);
1091                         commit->parents = xmalloc(sizeof(struct commit_list));
1092                         commit->parents->item = parents[i];
1093                         commit->parents->next = NULL;
1094                         free(parents);
1095                         free(cand);
1096                         free_diffqueues(nparents, diffqueues);
1097                         /* NEEDSWORK leaking like a sieve */
1098                         return 0;
1099                 }
1100         }
1101
1102         /*
1103          * No single parent took the blame.  We add the candidates
1104          * from the above loop to the parents.
1105          */
1106         for (i = 0; i < nparents; i++) {
1107                 add_line_range(rev, parents[i], cand[i]);
1108         }
1109
1110         clear_commit_line_range(rev, commit);
1111         free(parents);
1112         free(cand);
1113         free_diffqueues(nparents, diffqueues);
1114         return 1;
1115
1116         /* NEEDSWORK evil merge detection stuff */
1117         /* NEEDSWORK leaking like a sieve */
1118 }
1119
1120 static int process_ranges_arbitrary_commit(struct rev_info *rev, struct commit *commit)
1121 {
1122         struct line_log_data *range = lookup_line_range(rev, commit);
1123         int changed = 0;
1124
1125         if (range) {
1126                 if (!commit->parents || !commit->parents->next)
1127                         changed = process_ranges_ordinary_commit(rev, commit, range);
1128                 else
1129                         changed = process_ranges_merge_commit(rev, commit, range);
1130         }
1131
1132         if (!changed)
1133                 commit->object.flags |= TREESAME;
1134
1135         return changed;
1136 }
1137
1138 static enum rewrite_result line_log_rewrite_one(struct rev_info *rev, struct commit **pp)
1139 {
1140         for (;;) {
1141                 struct commit *p = *pp;
1142                 if (p->parents && p->parents->next)
1143                         return rewrite_one_ok;
1144                 if (p->object.flags & UNINTERESTING)
1145                         return rewrite_one_ok;
1146                 if (!(p->object.flags & TREESAME))
1147                         return rewrite_one_ok;
1148                 if (!p->parents)
1149                         return rewrite_one_noparents;
1150                 *pp = p->parents->item;
1151         }
1152 }
1153
1154 int line_log_filter(struct rev_info *rev)
1155 {
1156         struct commit *commit;
1157         struct commit_list *list = rev->commits;
1158         struct commit_list *out = NULL, **pp = &out;
1159
1160         while (list) {
1161                 struct commit_list *to_free = NULL;
1162                 commit = list->item;
1163                 if (process_ranges_arbitrary_commit(rev, commit)) {
1164                         *pp = list;
1165                         pp = &list->next;
1166                 } else
1167                         to_free = list;
1168                 list = list->next;
1169                 free(to_free);
1170         }
1171         *pp = NULL;
1172
1173         for (list = out; list; list = list->next)
1174                 rewrite_parents(rev, list->item, line_log_rewrite_one);
1175
1176         rev->commits = out;
1177
1178         return 0;
1179 }