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 "userdiff.h"
  16 #include "line-log.h"
  17
  18 static void range_set_grow(struct range_set *rs, size_t extra)
  19 {
  20         ALLOC_GROW(rs->ranges, rs->nr + extra, rs->alloc);
  21 }
  22
  23 /* Either initialization would be fine */
  24 #define RANGE_SET_INIT {0}
  25
  26 void range_set_init(struct range_set *rs, size_t prealloc)
  27 {
  28         rs->alloc = rs->nr = 0;
  29         rs->ranges = NULL;
  30         if (prealloc)
  31                 range_set_grow(rs, prealloc);
  32 }
  33
  34 void range_set_release(struct range_set *rs)
  35 {
  36         free(rs->ranges);
  37         rs->alloc = rs->nr = 0;
  38         rs->ranges = NULL;
  39 }
  40
  41 /* dst must be uninitialized! */
  42 static void range_set_copy(struct range_set *dst, struct range_set *src)
  43 {
  44         range_set_init(dst, src->nr);
  45         memcpy(dst->ranges, src->ranges, src->nr*sizeof(struct range_set));
  46         dst->nr = src->nr;
  47 }
  48 static void range_set_move(struct range_set *dst, struct range_set *src)
  49 {
  50         range_set_release(dst);
  51         dst->ranges = src->ranges;
  52         dst->nr = src->nr;
  53         dst->alloc = src->alloc;
  54         src->ranges = NULL;
  55         src->alloc = src->nr = 0;
  56 }
  57
  58 /* tack on a _new_ range _at the end_ */
  59 void range_set_append_unsafe(struct range_set *rs, long a, long b)
  60 {
  61         assert(a <= b);
  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 void range_set_append(struct range_set *rs, long a, long b)
  69 {
  70         assert(rs->nr == 0 || rs->ranges[rs->nr-1].end <= a);
  71         range_set_append_unsafe(rs, a, b);
  72 }
  73
  74 static int range_cmp(const void *_r, const void *_s)
  75 {
  76         const struct range *r = _r;
  77         const struct range *s = _s;
  78
  79         /* this could be simply 'return r.start-s.start', but for the types */
  80         if (r->start == s->start)
  81                 return 0;
  82         if (r->start < s->start)
  83                 return -1;
  84         return 1;
  85 }
  86
  87 /*
  88  * Check that the ranges are non-empty, sorted and non-overlapping
  89  */
  90 static void range_set_check_invariants(struct range_set *rs)
  91 {
  92         int i;
  93
  94         if (!rs)
  95                 return;
  96
  97         if (rs->nr)
  98                 assert(rs->ranges[0].start < rs->ranges[0].end);
  99
 100         for (i = 1; i < rs->nr; i++) {
 101                 assert(rs->ranges[i-1].end < rs->ranges[i].start);
 102                 assert(rs->ranges[i].start < rs->ranges[i].end);
 103         }
 104 }
 105
 106 /*
 107  * In-place pass of sorting and merging the ranges in the range set,
 108  * to establish the invariants when we get the ranges from the user
 109  */
 110 void sort_and_merge_range_set(struct range_set *rs)
 111 {
 112         int i;
 113         int o = 0; /* output cursor */
 114
 115         qsort(rs->ranges, rs->nr, sizeof(struct range), range_cmp);
 116
 117         for (i = 0; i < rs->nr; i++) {
 118                 if (rs->ranges[i].start == rs->ranges[i].end)
 119                         continue;
 120                 if (o > 0 && rs->ranges[i].start <= rs->ranges[o-1].end) {
 121                         if (rs->ranges[o-1].end < rs->ranges[i].end)
 122                                 rs->ranges[o-1].end = rs->ranges[i].end;
 123                 } else {
 124                         rs->ranges[o].start = rs->ranges[i].start;
 125                         rs->ranges[o].end = rs->ranges[i].end;
 126                         o++;
 127                 }
 128         }
 129         assert(o <= rs->nr);
 130         rs->nr = o;
 131
 132         range_set_check_invariants(rs);
 133 }
 134
 135 /*
 136  * Union of range sets (i.e., sets of line numbers).  Used to merge
 137  * them when searches meet at a common ancestor.
 138  *
 139  * This is also where the ranges are consolidated into canonical form:
 140  * overlapping and adjacent ranges are merged, and empty ranges are
 141  * removed.
 142  */
 143 static void range_set_union(struct range_set *out,
 144                              struct range_set *a, struct range_set *b)
 145 {
 146         int i = 0, j = 0, o = 0;
 147         struct range *ra = a->ranges;
 148         struct range *rb = b->ranges;
 149         /* cannot make an alias of out->ranges: it may change during grow */
 150
 151         assert(out->nr == 0);
 152         while (i < a->nr || j < b->nr) {
 153                 struct range *new;
 154                 if (i < a->nr && j < b->nr) {
 155                         if (ra[i].start < rb[j].start)
 156                                 new = &ra[i++];
 157                         else if (ra[i].start > rb[j].start)
 158                                 new = &rb[j++];
 159                         else if (ra[i].end < rb[j].end)
 160                                 new = &ra[i++];
 161                         else
 162                                 new = &rb[j++];
 163                 } else if (i < a->nr)      /* b exhausted */
 164                         new = &ra[i++];
 165                 else                       /* a exhausted */
 166                         new = &rb[j++];
 167                 if (new->start == new->end)
 168                         ; /* empty range */
 169                 else if (!o || out->ranges[o-1].end < new->start) {
 170                         range_set_grow(out, 1);
 171                         out->ranges[o].start = new->start;
 172                         out->ranges[o].end = new->end;
 173                         o++;
 174                 } else if (out->ranges[o-1].end < new->end) {
 175                         out->ranges[o-1].end = new->end;
 176                 }
 177         }
 178         out->nr = o;
 179 }
 180
 181 /*
 182  * Difference of range sets (out = a \ b).  Pass the "interesting"
 183  * ranges as 'a' and the target side of the diff as 'b': it removes
 184  * the ranges for which the commit is responsible.
 185  */
 186 static void range_set_difference(struct range_set *out,
 187                                   struct range_set *a, struct range_set *b)
 188 {
 189         int i, j =  0;
 190         for (i = 0; i < a->nr; i++) {
 191                 long start = a->ranges[i].start;
 192                 long end = a->ranges[i].end;
 193                 while (start < end) {
 194                         while (j < b->nr && start >= b->ranges[j].end)
 195                                 /*
 196                                  * a:         |-------
 197                                  * b: ------|
 198                                  */
 199                                 j++;
 200                         if (j >= b->nr || end < b->ranges[j].start) {
 201                                 /*
 202                                  * b exhausted, or
 203                                  * a:  ----|
 204                                  * b:         |----
 205                                  */
 206                                 range_set_append(out, start, end);
 207                                 break;
 208                         }
 209                         if (start >= b->ranges[j].start) {
 210                                 /*
 211                                  * a:     |--????
 212                                  * b: |------|
 213                                  */
 214                                 start = b->ranges[j].end;
 215                         } else if (end > b->ranges[j].start) {
 216                                 /*
 217                                  * a: |-----|
 218                                  * b:    |--?????
 219                                  */
 220                                 if (start < b->ranges[j].start)
 221                                         range_set_append(out, start, b->ranges[j].start);
 222                                 start = b->ranges[j].end;
 223                         }
 224                 }
 225         }
 226 }
 227
 228 static void diff_ranges_init(struct diff_ranges *diff)
 229 {
 230         range_set_init(&diff->parent, 0);
 231         range_set_init(&diff->target, 0);
 232 }
 233
 234 static void diff_ranges_release(struct diff_ranges *diff)
 235 {
 236         range_set_release(&diff->parent);
 237         range_set_release(&diff->target);
 238 }
 239
 240 void line_log_data_init(struct line_log_data *r)
 241 {
 242         memset(r, 0, sizeof(struct line_log_data));
 243         range_set_init(&r->ranges, 0);
 244 }
 245
 246 static void line_log_data_clear(struct line_log_data *r)
 247 {
 248         range_set_release(&r->ranges);
 249         if (r->pair)
 250                 diff_free_filepair(r->pair);
 251 }
 252
 253 static void free_line_log_data(struct line_log_data *r)
 254 {
 255         while (r) {
 256                 struct line_log_data *next = r->next;
 257                 line_log_data_clear(r);
 258                 free(r);
 259                 r = next;
 260         }
 261 }
 262
 263 static struct line_log_data *
 264 search_line_log_data(struct line_log_data *list, const char *path,
 265                      struct line_log_data **insertion_point)
 266 {
 267         struct line_log_data *p = list;
 268         if (insertion_point)
 269                 *insertion_point = NULL;
 270         while (p) {
 271                 int cmp = strcmp(p->path, path);
 272                 if (!cmp)
 273                         return p;
 274                 if (insertion_point && cmp < 0)
 275                         *insertion_point = p;
 276                 p = p->next;
 277         }
 278         return NULL;
 279 }
 280
 281 /*
 282  * Note: takes ownership of 'path', which happens to be what the only
 283  * caller needs.
 284  */
 285 static void line_log_data_insert(struct line_log_data **list,
 286                                  char *path,
 287                                  long begin, long end)
 288 {
 289         struct line_log_data *ip;
 290         struct line_log_data *p = search_line_log_data(*list, path, &ip);
 291
 292         if (p) {
 293                 range_set_append_unsafe(&p->ranges, begin, end);
 294                 free(path);
 295                 return;
 296         }
 297
 298         p = xcalloc(1, sizeof(struct line_log_data));
 299         p->path = path;
 300         range_set_append(&p->ranges, begin, end);
 301         if (ip) {
 302                 p->next = ip->next;
 303                 ip->next = p;
 304         } else {
 305                 p->next = *list;
 306                 *list = p;
 307         }
 308 }
 309
 310 struct collect_diff_cbdata {
 311         struct diff_ranges *diff;
 312 };
 313
 314 static int collect_diff_cb(long start_a, long count_a,
 315                            long start_b, long count_b,
 316                            void *data)
 317 {
 318         struct collect_diff_cbdata *d = data;
 319
 320         if (count_a >= 0)
 321                 range_set_append(&d->diff->parent, start_a, start_a + count_a);
 322         if (count_b >= 0)
 323                 range_set_append(&d->diff->target, start_b, start_b + count_b);
 324
 325         return 0;
 326 }
 327
 328 static void collect_diff(mmfile_t *parent, mmfile_t *target, struct diff_ranges *out)
 329 {
 330         struct collect_diff_cbdata cbdata = {NULL};
 331         xpparam_t xpp;
 332         xdemitconf_t xecfg;
 333         xdemitcb_t ecb;
 334
 335         memset(&xpp, 0, sizeof(xpp));
 336         memset(&xecfg, 0, sizeof(xecfg));
 337         xecfg.ctxlen = xecfg.interhunkctxlen = 0;
 338
 339         cbdata.diff = out;
 340         xecfg.hunk_func = collect_diff_cb;
 341         memset(&ecb, 0, sizeof(ecb));
 342         ecb.priv = &cbdata;
 343         xdi_diff(parent, target, &xpp, &xecfg, &ecb);
 344 }
 345
 346 /*
 347  * These are handy for debugging.  Removing them with #if 0 silences
 348  * the "unused function" warning.
 349  */
 350 #if 0
 351 static void dump_range_set(struct range_set *rs, const char *desc)
 352 {
 353         int i;
 354         printf("range set %s (%d items):\n", desc, rs->nr);
 355         for (i = 0; i < rs->nr; i++)
 356                 printf("\t[%ld,%ld]\n", rs->ranges[i].start, rs->ranges[i].end);
 357 }
 358
 359 static void dump_line_log_data(struct line_log_data *r)
 360 {
 361         char buf[4096];
 362         while (r) {
 363                 snprintf(buf, 4096, "file %s\n", r->path);
 364                 dump_range_set(&r->ranges, buf);
 365                 r = r->next;
 366         }
 367 }
 368
 369 static void dump_diff_ranges(struct diff_ranges *diff, const char *desc)
 370 {
 371         int i;
 372         assert(diff->parent.nr == diff->target.nr);
 373         printf("diff ranges %s (%d items):\n", desc, diff->parent.nr);
 374         printf("\tparent\ttarget\n");
 375         for (i = 0; i < diff->parent.nr; i++) {
 376                 printf("\t[%ld,%ld]\t[%ld,%ld]\n",
 377                        diff->parent.ranges[i].start,
 378                        diff->parent.ranges[i].end,
 379                        diff->target.ranges[i].start,
 380                        diff->target.ranges[i].end);
 381         }
 382 }
 383 #endif
 384
 385
 386 static int ranges_overlap(struct range *a, struct range *b)
 387 {
 388         return !(a->end <= b->start || b->end <= a->start);
 389 }
 390
 391 /*
 392  * Given a diff and the set of interesting ranges, determine all hunks
 393  * of the diff which touch (overlap) at least one of the interesting
 394  * ranges in the target.
 395  */
 396 static void diff_ranges_filter_touched(struct diff_ranges *out,
 397                                        struct diff_ranges *diff,
 398                                        struct range_set *rs)
 399 {
 400         int i, j = 0;
 401
 402         assert(out->target.nr == 0);
 403
 404         for (i = 0; i < diff->target.nr; i++) {
 405                 while (diff->target.ranges[i].start > rs->ranges[j].end) {
 406                         j++;
 407                         if (j == rs->nr)
 408                                 return;
 409                 }
 410                 if (ranges_overlap(&diff->target.ranges[i], &rs->ranges[j])) {
 411                         range_set_append(&out->parent,
 412                                          diff->parent.ranges[i].start,
 413                                          diff->parent.ranges[i].end);
 414                         range_set_append(&out->target,
 415                                          diff->target.ranges[i].start,
 416                                          diff->target.ranges[i].end);
 417                 }
 418         }
 419 }
 420
 421 /*
 422  * Adjust the line counts in 'rs' to account for the lines
 423  * added/removed in the diff.
 424  */
 425 static void range_set_shift_diff(struct range_set *out,
 426                                  struct range_set *rs,
 427                                  struct diff_ranges *diff)
 428 {
 429         int i, j = 0;
 430         long offset = 0;
 431         struct range *src = rs->ranges;
 432         struct range *target = diff->target.ranges;
 433         struct range *parent = diff->parent.ranges;
 434
 435         for (i = 0; i < rs->nr; i++) {
 436                 while (j < diff->target.nr && src[i].start >= target[j].start) {
 437                         offset += (parent[j].end-parent[j].start)
 438                                 - (target[j].end-target[j].start);
 439                         j++;
 440                 }
 441                 range_set_append(out, src[i].start+offset, src[i].end+offset);
 442         }
 443 }
 444
 445 /*
 446  * Given a diff and the set of interesting ranges, map the ranges
 447  * across the diff.  That is: observe that the target commit takes
 448  * blame for all the + (target-side) ranges.  So for every pair of
 449  * ranges in the diff that was touched, we remove the latter and add
 450  * its parent side.
 451  */
 452 static void range_set_map_across_diff(struct range_set *out,
 453                                       struct range_set *rs,
 454                                       struct diff_ranges *diff,
 455                                       struct diff_ranges **touched_out)
 456 {
 457         struct diff_ranges *touched = xmalloc(sizeof(*touched));
 458         struct range_set tmp1 = RANGE_SET_INIT;
 459         struct range_set tmp2 = RANGE_SET_INIT;
 460
 461         diff_ranges_init(touched);
 462         diff_ranges_filter_touched(touched, diff, rs);
 463         range_set_difference(&tmp1, rs, &touched->target);
 464         range_set_shift_diff(&tmp2, &tmp1, diff);
 465         range_set_union(out, &tmp2, &touched->parent);
 466         range_set_release(&tmp1);
 467         range_set_release(&tmp2);
 468
 469         *touched_out = touched;
 470 }
 471
 472 static struct commit *check_single_commit(struct rev_info *revs)
 473 {
 474         struct object *commit = NULL;
 475         int found = -1;
 476         int i;
 477
 478         for (i = 0; i < revs->pending.nr; i++) {
 479                 struct object *obj = revs->pending.objects[i].item;
 480                 if (obj->flags & UNINTERESTING)
 481                         continue;
 482                 while (obj->type == OBJ_TAG)
 483                         obj = deref_tag(obj, NULL, 0);
 484                 if (obj->type != OBJ_COMMIT)
 485                         die("Non commit %s?", revs->pending.objects[i].name);
 486                 if (commit)
 487                         die("More than one commit to dig from: %s and %s?",
 488                             revs->pending.objects[i].name,
 489                             revs->pending.objects[found].name);
 490                 commit = obj;
 491                 found = i;
 492         }
 493
 494         if (!commit)
 495                 die("No commit specified?");
 496
 497         return (struct commit *) commit;
 498 }
 499
 500 static void fill_blob_sha1(struct commit *commit, struct diff_filespec *spec)
 501 {
 502         unsigned mode;
 503         unsigned char sha1[20];
 504
 505         if (get_tree_entry(commit->object.sha1, spec->path,
 506                            sha1, &mode))
 507                 die("There is no path %s in the commit", spec->path);
 508         fill_filespec(spec, sha1, 1, mode);
 509
 510         return;
 511 }
 512
 513 static void fill_line_ends(struct diff_filespec *spec, long *lines,
 514                            unsigned long **line_ends)
 515 {
 516         int num = 0, size = 50;
 517         long cur = 0;
 518         unsigned long *ends = NULL;
 519         char *data = NULL;
 520
 521         if (diff_populate_filespec(spec, 0))
 522                 die("Cannot read blob %s", sha1_to_hex(spec->sha1));
 523
 524         ends = xmalloc(size * sizeof(*ends));
 525         ends[cur++] = 0;
 526         data = spec->data;
 527         while (num < spec->size) {
 528                 if (data[num] == '\n' || num == spec->size - 1) {
 529                         ALLOC_GROW(ends, (cur + 1), size);
 530                         ends[cur++] = num;
 531                 }
 532                 num++;
 533         }
 534
 535         /* shrink the array to fit the elements */
 536         REALLOC_ARRAY(ends, cur);
 537         *lines = cur-1;
 538         *line_ends = ends;
 539 }
 540
 541 struct nth_line_cb {
 542         struct diff_filespec *spec;
 543         long lines;
 544         unsigned long *line_ends;
 545 };
 546
 547 static const char *nth_line(void *data, long line)
 548 {
 549         struct nth_line_cb *d = data;
 550         assert(d && line <= d->lines);
 551         assert(d->spec && d->spec->data);
 552
 553         if (line == 0)
 554                 return (char *)d->spec->data;
 555         else
 556                 return (char *)d->spec->data + d->line_ends[line] + 1;
 557 }
 558
 559 static struct line_log_data *
 560 parse_lines(struct commit *commit, const char *prefix, struct string_list *args)
 561 {
 562         long lines = 0;
 563         unsigned long *ends = NULL;
 564         struct nth_line_cb cb_data;
 565         struct string_list_item *item;
 566         struct line_log_data *ranges = NULL;
 567         struct line_log_data *p;
 568
 569         for_each_string_list_item(item, args) {
 570                 const char *name_part, *range_part;
 571                 char *full_name;
 572                 struct diff_filespec *spec;
 573                 long begin = 0, end = 0;
 574                 long anchor;
 575
 576                 name_part = skip_range_arg(item->string);
 577                 if (!name_part || *name_part != ':' || !name_part[1])
 578                         die("-L argument '%s' not of the form start,end:file",
 579                             item->string);
 580                 range_part = xstrndup(item->string, name_part - item->string);
 581                 name_part++;
 582
 583                 full_name = prefix_path(prefix, prefix ? strlen(prefix) : 0,
 584                                         name_part);
 585
 586                 spec = alloc_filespec(full_name);
 587                 fill_blob_sha1(commit, spec);
 588                 fill_line_ends(spec, &lines, &ends);
 589                 cb_data.spec = spec;
 590                 cb_data.lines = lines;
 591                 cb_data.line_ends = ends;
 592
 593                 p = search_line_log_data(ranges, full_name, NULL);
 594                 if (p && p->ranges.nr)
 595                         anchor = p->ranges.ranges[p->ranges.nr - 1].end + 1;
 596                 else
 597                         anchor = 1;
 598
 599                 if (parse_range_arg(range_part, nth_line, &cb_data,
 600                                     lines, anchor, &begin, &end,
 601                                     full_name))
 602                         die("malformed -L argument '%s'", range_part);
 603                 if (lines < end || ((lines || begin) && lines < begin))
 604                         die("file %s has only %lu lines", name_part, lines);
 605                 if (begin < 1)
 606                         begin = 1;
 607                 if (end < 1)
 608                         end = lines;
 609                 begin--;
 610                 line_log_data_insert(&ranges, full_name, begin, end);
 611
 612                 free_filespec(spec);
 613                 free(ends);
 614                 ends = NULL;
 615         }
 616
 617         for (p = ranges; p; p = p->next)
 618                 sort_and_merge_range_set(&p->ranges);
 619
 620         return ranges;
 621 }
 622
 623 static struct line_log_data *line_log_data_copy_one(struct line_log_data *r)
 624 {
 625         struct line_log_data *ret = xmalloc(sizeof(*ret));
 626
 627         assert(r);
 628         line_log_data_init(ret);
 629         range_set_copy(&ret->ranges, &r->ranges);
 630
 631         ret->path = xstrdup(r->path);
 632
 633         return ret;
 634 }
 635
 636 static struct line_log_data *
 637 line_log_data_copy(struct line_log_data *r)
 638 {
 639         struct line_log_data *ret = NULL;
 640         struct line_log_data *tmp = NULL, *prev = NULL;
 641
 642         assert(r);
 643         ret = tmp = prev = line_log_data_copy_one(r);
 644         r = r->next;
 645         while (r) {
 646                 tmp = line_log_data_copy_one(r);
 647                 prev->next = tmp;
 648                 prev = tmp;
 649                 r = r->next;
 650         }
 651
 652         return ret;
 653 }
 654
 655 /* merge two range sets across files */
 656 static struct line_log_data *line_log_data_merge(struct line_log_data *a,
 657                                                  struct line_log_data *b)
 658 {
 659         struct line_log_data *head = NULL, **pp = &head;
 660
 661         while (a || b) {
 662                 struct line_log_data *src;
 663                 struct line_log_data *src2 = NULL;
 664                 struct line_log_data *d;
 665                 int cmp;
 666                 if (!a)
 667                         cmp = 1;
 668                 else if (!b)
 669                         cmp = -1;
 670                 else
 671                         cmp = strcmp(a->path, b->path);
 672                 if (cmp < 0) {
 673                         src = a;
 674                         a = a->next;
 675                 } else if (cmp == 0) {
 676                         src = a;
 677                         a = a->next;
 678                         src2 = b;
 679                         b = b->next;
 680                 } else {
 681                         src = b;
 682                         b = b->next;
 683                 }
 684                 d = xmalloc(sizeof(struct line_log_data));
 685                 line_log_data_init(d);
 686                 d->path = xstrdup(src->path);
 687                 *pp = d;
 688                 pp = &d->next;
 689                 if (src2)
 690                         range_set_union(&d->ranges, &src->ranges, &src2->ranges);
 691                 else
 692                         range_set_copy(&d->ranges, &src->ranges);
 693         }
 694
 695         return head;
 696 }
 697
 698 static void add_line_range(struct rev_info *revs, struct commit *commit,
 699                            struct line_log_data *range)
 700 {
 701         struct line_log_data *old = NULL;
 702         struct line_log_data *new = NULL;
 703
 704         old = lookup_decoration(&revs->line_log_data, &commit->object);
 705         if (old && range) {
 706                 new = line_log_data_merge(old, range);
 707                 free_line_log_data(old);
 708         } else if (range)
 709                 new = line_log_data_copy(range);
 710
 711         if (new)
 712                 add_decoration(&revs->line_log_data, &commit->object, new);
 713 }
 714
 715 static void clear_commit_line_range(struct rev_info *revs, struct commit *commit)
 716 {
 717         struct line_log_data *r;
 718         r = lookup_decoration(&revs->line_log_data, &commit->object);
 719         if (!r)
 720                 return;
 721         free_line_log_data(r);
 722         add_decoration(&revs->line_log_data, &commit->object, NULL);
 723 }
 724
 725 static struct line_log_data *lookup_line_range(struct rev_info *revs,
 726                                                struct commit *commit)
 727 {
 728         struct line_log_data *ret = NULL;
 729         struct line_log_data *d;
 730
 731         ret = lookup_decoration(&revs->line_log_data, &commit->object);
 732
 733         for (d = ret; d; d = d->next)
 734                 range_set_check_invariants(&d->ranges);
 735
 736         return ret;
 737 }
 738
 739 void line_log_init(struct rev_info *rev, const char *prefix, struct string_list *args)
 740 {
 741         struct commit *commit = NULL;
 742         struct line_log_data *range;
 743
 744         commit = check_single_commit(rev);
 745         range = parse_lines(commit, prefix, args);
 746         add_line_range(rev, commit, range);
 747
 748         if (!rev->diffopt.detect_rename) {
 749                 int i, count = 0;
 750                 struct line_log_data *r = range;
 751                 const char **paths;
 752                 while (r) {
 753                         count++;
 754                         r = r->next;
 755                 }
 756                 paths = xmalloc((count+1)*sizeof(char *));
 757                 r = range;
 758                 for (i = 0; i < count; i++) {
 759                         paths[i] = xstrdup(r->path);
 760                         r = r->next;
 761                 }
 762                 paths[count] = NULL;
 763                 parse_pathspec(&rev->diffopt.pathspec, 0,
 764                                PATHSPEC_PREFER_FULL, "", paths);
 765                 free(paths);
 766         }
 767 }
 768
 769 static void move_diff_queue(struct diff_queue_struct *dst,
 770                             struct diff_queue_struct *src)
 771 {
 772         assert(src != dst);
 773         memcpy(dst, src, sizeof(struct diff_queue_struct));
 774         DIFF_QUEUE_CLEAR(src);
 775 }
 776
 777 static void filter_diffs_for_paths(struct line_log_data *range, int keep_deletions)
 778 {
 779         int i;
 780         struct diff_queue_struct outq;
 781         DIFF_QUEUE_CLEAR(&outq);
 782
 783         for (i = 0; i < diff_queued_diff.nr; i++) {
 784                 struct diff_filepair *p = diff_queued_diff.queue[i];
 785                 struct line_log_data *rg = NULL;
 786
 787                 if (!DIFF_FILE_VALID(p->two)) {
 788                         if (keep_deletions)
 789                                 diff_q(&outq, p);
 790                         else
 791                                 diff_free_filepair(p);
 792                         continue;
 793                 }
 794                 for (rg = range; rg; rg = rg->next) {
 795                         if (!strcmp(rg->path, p->two->path))
 796                                 break;
 797                 }
 798                 if (rg)
 799                         diff_q(&outq, p);
 800                 else
 801                         diff_free_filepair(p);
 802         }
 803         free(diff_queued_diff.queue);
 804         diff_queued_diff = outq;
 805 }
 806
 807 static inline int diff_might_be_rename(void)
 808 {
 809         int i;
 810         for (i = 0; i < diff_queued_diff.nr; i++)
 811                 if (!DIFF_FILE_VALID(diff_queued_diff.queue[i]->one)) {
 812                         /* fprintf(stderr, "diff_might_be_rename found creation of: %s\n", */
 813                         /*      diff_queued_diff.queue[i]->two->path); */
 814                         return 1;
 815                 }
 816         return 0;
 817 }
 818
 819 static void queue_diffs(struct line_log_data *range,
 820                         struct diff_options *opt,
 821                         struct diff_queue_struct *queue,
 822                         struct commit *commit, struct commit *parent)
 823 {
 824         assert(commit);
 825
 826         DIFF_QUEUE_CLEAR(&diff_queued_diff);
 827         diff_tree_sha1(parent ? parent->tree->object.sha1 : NULL,
 828                         commit->tree->object.sha1, "", opt);
 829         if (opt->detect_rename) {
 830                 filter_diffs_for_paths(range, 1);
 831                 if (diff_might_be_rename())
 832                         diffcore_std(opt);
 833                 filter_diffs_for_paths(range, 0);
 834         }
 835         move_diff_queue(queue, &diff_queued_diff);
 836 }
 837
 838 static char *get_nth_line(long line, unsigned long *ends, void *data)
 839 {
 840         if (line == 0)
 841                 return (char *)data;
 842         else
 843                 return (char *)data + ends[line] + 1;
 844 }
 845
 846 static void print_line(const char *prefix, char first,
 847                        long line, unsigned long *ends, void *data,
 848                        const char *color, const char *reset)
 849 {
 850         char *begin = get_nth_line(line, ends, data);
 851         char *end = get_nth_line(line+1, ends, data);
 852         int had_nl = 0;
 853
 854         if (end > begin && end[-1] == '\n') {
 855                 end--;
 856                 had_nl = 1;
 857         }
 858
 859         fputs(prefix, stdout);
 860         fputs(color, stdout);
 861         putchar(first);
 862         fwrite(begin, 1, end-begin, stdout);
 863         fputs(reset, stdout);
 864         putchar('\n');
 865         if (!had_nl)
 866                 fputs("\\ No newline at end of file\n", stdout);
 867 }
 868
 869 static char *output_prefix(struct diff_options *opt)
 870 {
 871         char *prefix = "";
 872
 873         if (opt->output_prefix) {
 874                 struct strbuf *sb = opt->output_prefix(opt, opt->output_prefix_data);
 875                 prefix = sb->buf;
 876         }
 877
 878         return prefix;
 879 }
 880
 881 static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *range)
 882 {
 883         int i, j = 0;
 884         long p_lines, t_lines;
 885         unsigned long *p_ends = NULL, *t_ends = NULL;
 886         struct diff_filepair *pair = range->pair;
 887         struct diff_ranges *diff = &range->diff;
 888
 889         struct diff_options *opt = &rev->diffopt;
 890         char *prefix = output_prefix(opt);
 891         const char *c_reset = diff_get_color(opt->use_color, DIFF_RESET);
 892         const char *c_frag = diff_get_color(opt->use_color, DIFF_FRAGINFO);
 893         const char *c_meta = diff_get_color(opt->use_color, DIFF_METAINFO);
 894         const char *c_old = diff_get_color(opt->use_color, DIFF_FILE_OLD);
 895         const char *c_new = diff_get_color(opt->use_color, DIFF_FILE_NEW);
 896         const char *c_plain = diff_get_color(opt->use_color, DIFF_PLAIN);
 897
 898         if (!pair || !diff)
 899                 return;
 900
 901         if (pair->one->sha1_valid)
 902                 fill_line_ends(pair->one, &p_lines, &p_ends);
 903         fill_line_ends(pair->two, &t_lines, &t_ends);
 904
 905         printf("%s%sdiff --git a/%s b/%s%s\n", prefix, c_meta, pair->one->path, pair->two->path, c_reset);
 906         printf("%s%s--- %s%s%s\n", prefix, c_meta,
 907                pair->one->sha1_valid ? "a/" : "",
 908                pair->one->sha1_valid ? pair->one->path : "/dev/null",
 909                c_reset);
 910         printf("%s%s+++ b/%s%s\n", prefix, c_meta, pair->two->path, c_reset);
 911         for (i = 0; i < range->ranges.nr; i++) {
 912                 long p_start, p_end;
 913                 long t_start = range->ranges.ranges[i].start;
 914                 long t_end = range->ranges.ranges[i].end;
 915                 long t_cur = t_start;
 916                 int j_last;
 917
 918                 while (j < diff->target.nr && diff->target.ranges[j].end < t_start)
 919                         j++;
 920                 if (j == diff->target.nr || diff->target.ranges[j].start > t_end)
 921                         continue;
 922
 923                 /* Scan ahead to determine the last diff that falls in this range */
 924                 j_last = j;
 925                 while (j_last < diff->target.nr && diff->target.ranges[j_last].start < t_end)
 926                         j_last++;
 927                 if (j_last > j)
 928                         j_last--;
 929
 930                 /*
 931                  * Compute parent hunk headers: we know that the diff
 932                  * has the correct line numbers (but not all hunks).
 933                  * So it suffices to shift the start/end according to
 934                  * the line numbers of the first/last hunk(s) that
 935                  * fall in this range.
 936                  */
 937                 if (t_start < diff->target.ranges[j].start)
 938                         p_start = diff->parent.ranges[j].start - (diff->target.ranges[j].start-t_start);
 939                 else
 940                         p_start = diff->parent.ranges[j].start;
 941                 if (t_end > diff->target.ranges[j_last].end)
 942                         p_end = diff->parent.ranges[j_last].end + (t_end-diff->target.ranges[j_last].end);
 943                 else
 944                         p_end = diff->parent.ranges[j_last].end;
 945
 946                 if (!p_start && !p_end) {
 947                         p_start = -1;
 948                         p_end = -1;
 949                 }
 950
 951                 /* Now output a diff hunk for this range */
 952                 printf("%s%s@@ -%ld,%ld +%ld,%ld @@%s\n",
 953                        prefix, c_frag,
 954                        p_start+1, p_end-p_start, t_start+1, t_end-t_start,
 955                        c_reset);
 956                 while (j < diff->target.nr && diff->target.ranges[j].start < t_end) {
 957                         int k;
 958                         for (; t_cur < diff->target.ranges[j].start; t_cur++)
 959                                 print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
 960                                            c_plain, c_reset);
 961                         for (k = diff->parent.ranges[j].start; k < diff->parent.ranges[j].end; k++)
 962                                 print_line(prefix, '-', k, p_ends, pair->one->data,
 963                                            c_old, c_reset);
 964                         for (; t_cur < diff->target.ranges[j].end && t_cur < t_end; t_cur++)
 965                                 print_line(prefix, '+', t_cur, t_ends, pair->two->data,
 966                                            c_new, c_reset);
 967                         j++;
 968                 }
 969                 for (; t_cur < t_end; t_cur++)
 970                         print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
 971                                    c_plain, c_reset);
 972         }
 973
 974         free(p_ends);
 975         free(t_ends);
 976 }
 977
 978 /*
 979  * NEEDSWORK: manually building a diff here is not the Right
 980  * Thing(tm).  log -L should be built into the diff pipeline.
 981  */
 982 static void dump_diff_hacky(struct rev_info *rev, struct line_log_data *range)
 983 {
 984         puts(output_prefix(&rev->diffopt));
 985         while (range) {
 986                 dump_diff_hacky_one(rev, range);
 987                 range = range->next;
 988         }
 989 }
 990
 991 /*
 992  * Unlike most other functions, this destructively operates on
 993  * 'range'.
 994  */
 995 static int process_diff_filepair(struct rev_info *rev,
 996                                  struct diff_filepair *pair,
 997                                  struct line_log_data *range,
 998                                  struct diff_ranges **diff_out)
 999 {
1000         struct line_log_data *rg = range;
1001         struct range_set tmp;
1002         struct diff_ranges diff;
1003         mmfile_t file_parent, file_target;
1004
1005         assert(pair->two->path);
1006         while (rg) {
1007                 assert(rg->path);
1008                 if (!strcmp(rg->path, pair->two->path))
1009                         break;
1010                 rg = rg->next;
1011         }
1012
1013         if (!rg)
1014                 return 0;
1015         if (rg->ranges.nr == 0)
1016                 return 0;
1017
1018         assert(pair->two->sha1_valid);
1019         diff_populate_filespec(pair->two, 0);
1020         file_target.ptr = pair->two->data;
1021         file_target.size = pair->two->size;
1022
1023         if (pair->one->sha1_valid) {
1024                 diff_populate_filespec(pair->one, 0);
1025                 file_parent.ptr = pair->one->data;
1026                 file_parent.size = pair->one->size;
1027         } else {
1028                 file_parent.ptr = "";
1029                 file_parent.size = 0;
1030         }
1031
1032         diff_ranges_init(&diff);
1033         collect_diff(&file_parent, &file_target, &diff);
1034
1035         /* NEEDSWORK should apply some heuristics to prevent mismatches */
1036         free(rg->path);
1037         rg->path = xstrdup(pair->one->path);
1038
1039         range_set_init(&tmp, 0);
1040         range_set_map_across_diff(&tmp, &rg->ranges, &diff, diff_out);
1041         range_set_release(&rg->ranges);
1042         range_set_move(&rg->ranges, &tmp);
1043
1044         diff_ranges_release(&diff);
1045
1046         return ((*diff_out)->parent.nr > 0);
1047 }
1048
1049 static struct diff_filepair *diff_filepair_dup(struct diff_filepair *pair)
1050 {
1051         struct diff_filepair *new = xmalloc(sizeof(struct diff_filepair));
1052         new->one = pair->one;
1053         new->two = pair->two;
1054         new->one->count++;
1055         new->two->count++;
1056         return new;
1057 }
1058
1059 static void free_diffqueues(int n, struct diff_queue_struct *dq)
1060 {
1061         int i, j;
1062         for (i = 0; i < n; i++)
1063                 for (j = 0; j < dq[i].nr; j++)
1064                         diff_free_filepair(dq[i].queue[j]);
1065         free(dq);
1066 }
1067
1068 static int process_all_files(struct line_log_data **range_out,
1069                              struct rev_info *rev,
1070                              struct diff_queue_struct *queue,
1071                              struct line_log_data *range)
1072 {
1073         int i, changed = 0;
1074
1075         *range_out = line_log_data_copy(range);
1076
1077         for (i = 0; i < queue->nr; i++) {
1078                 struct diff_ranges *pairdiff = NULL;
1079                 struct diff_filepair *pair = queue->queue[i];
1080                 if (process_diff_filepair(rev, pair, *range_out, &pairdiff)) {
1081                         /*
1082                          * Store away the diff for later output.  We
1083                          * tuck it in the ranges we got as _input_,
1084                          * since that's the commit that caused the
1085                          * diff.
1086                          *
1087                          * NEEDSWORK not enough when we get around to
1088                          * doing something interesting with merges;
1089                          * currently each invocation on a merge parent
1090                          * trashes the previous one's diff.
1091                          *
1092                          * NEEDSWORK tramples over data structures not owned here
1093                          */
1094                         struct line_log_data *rg = range;
1095                         changed++;
1096                         while (rg && strcmp(rg->path, pair->two->path))
1097                                 rg = rg->next;
1098                         assert(rg);
1099                         rg->pair = diff_filepair_dup(queue->queue[i]);
1100                         memcpy(&rg->diff, pairdiff, sizeof(struct diff_ranges));
1101                 }
1102         }
1103
1104         return changed;
1105 }
1106
1107 int line_log_print(struct rev_info *rev, struct commit *commit)
1108 {
1109         struct line_log_data *range = lookup_line_range(rev, commit);
1110
1111         show_log(rev);
1112         dump_diff_hacky(rev, range);
1113         return 1;
1114 }
1115
1116 static int process_ranges_ordinary_commit(struct rev_info *rev, struct commit *commit,
1117                                           struct line_log_data *range)
1118 {
1119         struct commit *parent = NULL;
1120         struct diff_queue_struct queue;
1121         struct line_log_data *parent_range;
1122         int changed;
1123
1124         if (commit->parents)
1125                 parent = commit->parents->item;
1126
1127         queue_diffs(range, &rev->diffopt, &queue, commit, parent);
1128         changed = process_all_files(&parent_range, rev, &queue, range);
1129         if (parent)
1130                 add_line_range(rev, parent, parent_range);
1131         return changed;
1132 }
1133
1134 static int process_ranges_merge_commit(struct rev_info *rev, struct commit *commit,
1135                                        struct line_log_data *range)
1136 {
1137         struct diff_queue_struct *diffqueues;
1138         struct line_log_data **cand;
1139         struct commit **parents;
1140         struct commit_list *p;
1141         int i;
1142         int nparents = commit_list_count(commit->parents);
1143
1144         diffqueues = xmalloc(nparents * sizeof(*diffqueues));
1145         cand = xmalloc(nparents * sizeof(*cand));
1146         parents = xmalloc(nparents * sizeof(*parents));
1147
1148         p = commit->parents;
1149         for (i = 0; i < nparents; i++) {
1150                 parents[i] = p->item;
1151                 p = p->next;
1152                 queue_diffs(range, &rev->diffopt, &diffqueues[i], commit, parents[i]);
1153         }
1154
1155         for (i = 0; i < nparents; i++) {
1156                 int changed;
1157                 cand[i] = NULL;
1158                 changed = process_all_files(&cand[i], rev, &diffqueues[i], range);
1159                 if (!changed) {
1160                         /*
1161                          * This parent can take all the blame, so we
1162                          * don't follow any other path in history
1163                          */
1164                         add_line_range(rev, parents[i], cand[i]);
1165                         clear_commit_line_range(rev, commit);
1166                         commit_list_append(parents[i], &commit->parents);
1167                         free(parents);
1168                         free(cand);
1169                         free_diffqueues(nparents, diffqueues);
1170                         /* NEEDSWORK leaking like a sieve */
1171                         return 0;
1172                 }
1173         }
1174
1175         /*
1176          * No single parent took the blame.  We add the candidates
1177          * from the above loop to the parents.
1178          */
1179         for (i = 0; i < nparents; i++) {
1180                 add_line_range(rev, parents[i], cand[i]);
1181         }
1182
1183         clear_commit_line_range(rev, commit);
1184         free(parents);
1185         free(cand);
1186         free_diffqueues(nparents, diffqueues);
1187         return 1;
1188
1189         /* NEEDSWORK evil merge detection stuff */
1190         /* NEEDSWORK leaking like a sieve */
1191 }
1192
1193 static int process_ranges_arbitrary_commit(struct rev_info *rev, struct commit *commit)
1194 {
1195         struct line_log_data *range = lookup_line_range(rev, commit);
1196         int changed = 0;
1197
1198         if (range) {
1199                 if (!commit->parents || !commit->parents->next)
1200                         changed = process_ranges_ordinary_commit(rev, commit, range);
1201                 else
1202                         changed = process_ranges_merge_commit(rev, commit, range);
1203         }
1204
1205         if (!changed)
1206                 commit->object.flags |= TREESAME;
1207
1208         return changed;
1209 }
1210
1211 static enum rewrite_result line_log_rewrite_one(struct rev_info *rev, struct commit **pp)
1212 {
1213         for (;;) {
1214                 struct commit *p = *pp;
1215                 if (p->parents && p->parents->next)
1216                         return rewrite_one_ok;
1217                 if (p->object.flags & UNINTERESTING)
1218                         return rewrite_one_ok;
1219                 if (!(p->object.flags & TREESAME))
1220                         return rewrite_one_ok;
1221                 if (!p->parents)
1222                         return rewrite_one_noparents;
1223                 *pp = p->parents->item;
1224         }
1225 }
1226
1227 int line_log_filter(struct rev_info *rev)
1228 {
1229         struct commit *commit;
1230         struct commit_list *list = rev->commits;
1231         struct commit_list *out = NULL, **pp = &out;
1232
1233         while (list) {
1234                 struct commit_list *to_free = NULL;
1235                 commit = list->item;
1236                 if (process_ranges_arbitrary_commit(rev, commit)) {
1237                         *pp = list;
1238                         pp = &list->next;
1239                 } else
1240                         to_free = list;
1241                 list = list->next;
1242                 free(to_free);
1243         }
1244         *pp = NULL;
1245
1246         for (list = out; list; list = list->next)
1247                 rewrite_parents(rev, list->item, line_log_rewrite_one);
1248
1249         rev->commits = out;
1250
1251         return 0;
1252 }