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 static 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 static 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 static 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 static 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 static 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                 sort_and_merge_range_set(&p->ranges);
 295                 free(path);
 296                 return;
 297         }
 298
 299         p = xcalloc(1, sizeof(struct line_log_data));
 300         p->path = path;
 301         range_set_append(&p->ranges, begin, end);
 302         sort_and_merge_range_set(&p->ranges);
 303         if (ip) {
 304                 p->next = ip->next;
 305                 ip->next = p;
 306         } else {
 307                 p->next = *list;
 308                 *list = p;
 309         }
 310 }
 311
 312 struct collect_diff_cbdata {
 313         struct diff_ranges *diff;
 314 };
 315
 316 static int collect_diff_cb(long start_a, long count_a,
 317                            long start_b, long count_b,
 318                            void *data)
 319 {
 320         struct collect_diff_cbdata *d = data;
 321
 322         if (count_a >= 0)
 323                 range_set_append(&d->diff->parent, start_a, start_a + count_a);
 324         if (count_b >= 0)
 325                 range_set_append(&d->diff->target, start_b, start_b + count_b);
 326
 327         return 0;
 328 }
 329
 330 static void collect_diff(mmfile_t *parent, mmfile_t *target, struct diff_ranges *out)
 331 {
 332         struct collect_diff_cbdata cbdata = {NULL};
 333         xpparam_t xpp;
 334         xdemitconf_t xecfg;
 335         xdemitcb_t ecb;
 336
 337         memset(&xpp, 0, sizeof(xpp));
 338         memset(&xecfg, 0, sizeof(xecfg));
 339         xecfg.ctxlen = xecfg.interhunkctxlen = 0;
 340
 341         cbdata.diff = out;
 342         xecfg.hunk_func = collect_diff_cb;
 343         memset(&ecb, 0, sizeof(ecb));
 344         ecb.priv = &cbdata;
 345         xdi_diff(parent, target, &xpp, &xecfg, &ecb);
 346 }
 347
 348 /*
 349  * These are handy for debugging.  Removing them with #if 0 silences
 350  * the "unused function" warning.
 351  */
 352 #if 0
 353 static void dump_range_set(struct range_set *rs, const char *desc)
 354 {
 355         int i;
 356         printf("range set %s (%d items):\n", desc, rs->nr);
 357         for (i = 0; i < rs->nr; i++)
 358                 printf("\t[%ld,%ld]\n", rs->ranges[i].start, rs->ranges[i].end);
 359 }
 360
 361 static void dump_line_log_data(struct line_log_data *r)
 362 {
 363         char buf[4096];
 364         while (r) {
 365                 snprintf(buf, 4096, "file %s\n", r->path);
 366                 dump_range_set(&r->ranges, buf);
 367                 r = r->next;
 368         }
 369 }
 370
 371 static void dump_diff_ranges(struct diff_ranges *diff, const char *desc)
 372 {
 373         int i;
 374         assert(diff->parent.nr == diff->target.nr);
 375         printf("diff ranges %s (%d items):\n", desc, diff->parent.nr);
 376         printf("\tparent\ttarget\n");
 377         for (i = 0; i < diff->parent.nr; i++) {
 378                 printf("\t[%ld,%ld]\t[%ld,%ld]\n",
 379                        diff->parent.ranges[i].start,
 380                        diff->parent.ranges[i].end,
 381                        diff->target.ranges[i].start,
 382                        diff->target.ranges[i].end);
 383         }
 384 }
 385 #endif
 386
 387
 388 static int ranges_overlap(struct range *a, struct range *b)
 389 {
 390         return !(a->end <= b->start || b->end <= a->start);
 391 }
 392
 393 /*
 394  * Given a diff and the set of interesting ranges, determine all hunks
 395  * of the diff which touch (overlap) at least one of the interesting
 396  * ranges in the target.
 397  */
 398 static void diff_ranges_filter_touched(struct diff_ranges *out,
 399                                        struct diff_ranges *diff,
 400                                        struct range_set *rs)
 401 {
 402         int i, j = 0;
 403
 404         assert(out->target.nr == 0);
 405
 406         for (i = 0; i < diff->target.nr; i++) {
 407                 while (diff->target.ranges[i].start > rs->ranges[j].end) {
 408                         j++;
 409                         if (j == rs->nr)
 410                                 return;
 411                 }
 412                 if (ranges_overlap(&diff->target.ranges[i], &rs->ranges[j])) {
 413                         range_set_append(&out->parent,
 414                                          diff->parent.ranges[i].start,
 415                                          diff->parent.ranges[i].end);
 416                         range_set_append(&out->target,
 417                                          diff->target.ranges[i].start,
 418                                          diff->target.ranges[i].end);
 419                 }
 420         }
 421 }
 422
 423 /*
 424  * Adjust the line counts in 'rs' to account for the lines
 425  * added/removed in the diff.
 426  */
 427 static void range_set_shift_diff(struct range_set *out,
 428                                  struct range_set *rs,
 429                                  struct diff_ranges *diff)
 430 {
 431         int i, j = 0;
 432         long offset = 0;
 433         struct range *src = rs->ranges;
 434         struct range *target = diff->target.ranges;
 435         struct range *parent = diff->parent.ranges;
 436
 437         for (i = 0; i < rs->nr; i++) {
 438                 while (j < diff->target.nr && src[i].start >= target[j].start) {
 439                         offset += (parent[j].end-parent[j].start)
 440                                 - (target[j].end-target[j].start);
 441                         j++;
 442                 }
 443                 range_set_append(out, src[i].start+offset, src[i].end+offset);
 444         }
 445 }
 446
 447 /*
 448  * Given a diff and the set of interesting ranges, map the ranges
 449  * across the diff.  That is: observe that the target commit takes
 450  * blame for all the + (target-side) ranges.  So for every pair of
 451  * ranges in the diff that was touched, we remove the latter and add
 452  * its parent side.
 453  */
 454 static void range_set_map_across_diff(struct range_set *out,
 455                                       struct range_set *rs,
 456                                       struct diff_ranges *diff,
 457                                       struct diff_ranges **touched_out)
 458 {
 459         struct diff_ranges *touched = xmalloc(sizeof(*touched));
 460         struct range_set tmp1 = RANGE_SET_INIT;
 461         struct range_set tmp2 = RANGE_SET_INIT;
 462
 463         diff_ranges_init(touched);
 464         diff_ranges_filter_touched(touched, diff, rs);
 465         range_set_difference(&tmp1, rs, &touched->target);
 466         range_set_shift_diff(&tmp2, &tmp1, diff);
 467         range_set_union(out, &tmp2, &touched->parent);
 468         range_set_release(&tmp1);
 469         range_set_release(&tmp2);
 470
 471         *touched_out = touched;
 472 }
 473
 474 static struct commit *check_single_commit(struct rev_info *revs)
 475 {
 476         struct object *commit = NULL;
 477         int found = -1;
 478         int i;
 479
 480         for (i = 0; i < revs->pending.nr; i++) {
 481                 struct object *obj = revs->pending.objects[i].item;
 482                 if (obj->flags & UNINTERESTING)
 483                         continue;
 484                 while (obj->type == OBJ_TAG)
 485                         obj = deref_tag(obj, NULL, 0);
 486                 if (obj->type != OBJ_COMMIT)
 487                         die("Non commit %s?", revs->pending.objects[i].name);
 488                 if (commit)
 489                         die("More than one commit to dig from: %s and %s?",
 490                             revs->pending.objects[i].name,
 491                             revs->pending.objects[found].name);
 492                 commit = obj;
 493                 found = i;
 494         }
 495
 496         if (!commit)
 497                 die("No commit specified?");
 498
 499         return (struct commit *) commit;
 500 }
 501
 502 static void fill_blob_sha1(struct commit *commit, struct diff_filespec *spec)
 503 {
 504         unsigned mode;
 505         unsigned char sha1[20];
 506
 507         if (get_tree_entry(commit->object.sha1, spec->path,
 508                            sha1, &mode))
 509                 die("There is no path %s in the commit", spec->path);
 510         fill_filespec(spec, sha1, 1, mode);
 511
 512         return;
 513 }
 514
 515 static void fill_line_ends(struct diff_filespec *spec, long *lines,
 516                            unsigned long **line_ends)
 517 {
 518         int num = 0, size = 50;
 519         long cur = 0;
 520         unsigned long *ends = NULL;
 521         char *data = NULL;
 522
 523         if (diff_populate_filespec(spec, 0))
 524                 die("Cannot read blob %s", sha1_to_hex(spec->sha1));
 525
 526         ends = xmalloc(size * sizeof(*ends));
 527         ends[cur++] = 0;
 528         data = spec->data;
 529         while (num < spec->size) {
 530                 if (data[num] == '\n' || num == spec->size - 1) {
 531                         ALLOC_GROW(ends, (cur + 1), size);
 532                         ends[cur++] = num;
 533                 }
 534                 num++;
 535         }
 536
 537         /* shrink the array to fit the elements */
 538         ends = xrealloc(ends, cur * sizeof(*ends));
 539         *lines = cur-1;
 540         *line_ends = ends;
 541 }
 542
 543 struct nth_line_cb {
 544         struct diff_filespec *spec;
 545         long lines;
 546         unsigned long *line_ends;
 547 };
 548
 549 static const char *nth_line(void *data, long line)
 550 {
 551         struct nth_line_cb *d = data;
 552         assert(d && line <= d->lines);
 553         assert(d->spec && d->spec->data);
 554
 555         if (line == 0)
 556                 return (char *)d->spec->data;
 557         else
 558                 return (char *)d->spec->data + d->line_ends[line] + 1;
 559 }
 560
 561 static struct line_log_data *
 562 parse_lines(struct commit *commit, const char *prefix, struct string_list *args)
 563 {
 564         long lines = 0;
 565         unsigned long *ends = NULL;
 566         struct nth_line_cb cb_data;
 567         struct string_list_item *item;
 568         struct line_log_data *ranges = NULL;
 569
 570         for_each_string_list_item(item, args) {
 571                 const char *name_part, *range_part;
 572                 char *full_name;
 573                 struct diff_filespec *spec;
 574                 long begin = 0, end = 0;
 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                 if (parse_range_arg(range_part, nth_line, &cb_data,
 594                                     lines, &begin, &end,
 595                                     full_name))
 596                         die("malformed -L argument '%s'", range_part);
 597                 if (begin < 1)
 598                         begin = 1;
 599                 if (end < 1)
 600                         end = lines;
 601                 begin--;
 602                 if (lines < end || lines < begin)
 603                         die("file %s has only %ld lines", name_part, lines);
 604                 line_log_data_insert(&ranges, full_name, begin, end);
 605
 606                 free_filespec(spec);
 607                 free(ends);
 608                 ends = NULL;
 609         }
 610
 611         return ranges;
 612 }
 613
 614 static struct line_log_data *line_log_data_copy_one(struct line_log_data *r)
 615 {
 616         struct line_log_data *ret = xmalloc(sizeof(*ret));
 617
 618         assert(r);
 619         line_log_data_init(ret);
 620         range_set_copy(&ret->ranges, &r->ranges);
 621
 622         ret->path = xstrdup(r->path);
 623
 624         return ret;
 625 }
 626
 627 static struct line_log_data *
 628 line_log_data_copy(struct line_log_data *r)
 629 {
 630         struct line_log_data *ret = NULL;
 631         struct line_log_data *tmp = NULL, *prev = NULL;
 632
 633         assert(r);
 634         ret = tmp = prev = line_log_data_copy_one(r);
 635         r = r->next;
 636         while (r) {
 637                 tmp = line_log_data_copy_one(r);
 638                 prev->next = tmp;
 639                 prev = tmp;
 640                 r = r->next;
 641         }
 642
 643         return ret;
 644 }
 645
 646 /* merge two range sets across files */
 647 static struct line_log_data *line_log_data_merge(struct line_log_data *a,
 648                                                  struct line_log_data *b)
 649 {
 650         struct line_log_data *head = NULL, **pp = &head;
 651
 652         while (a || b) {
 653                 struct line_log_data *src;
 654                 struct line_log_data *src2 = NULL;
 655                 struct line_log_data *d;
 656                 int cmp;
 657                 if (!a)
 658                         cmp = 1;
 659                 else if (!b)
 660                         cmp = -1;
 661                 else
 662                         cmp = strcmp(a->path, b->path);
 663                 if (cmp < 0) {
 664                         src = a;
 665                         a = a->next;
 666                 } else if (cmp == 0) {
 667                         src = a;
 668                         a = a->next;
 669                         src2 = b;
 670                         b = b->next;
 671                 } else {
 672                         src = b;
 673                         b = b->next;
 674                 }
 675                 d = xmalloc(sizeof(struct line_log_data));
 676                 line_log_data_init(d);
 677                 d->path = xstrdup(src->path);
 678                 *pp = d;
 679                 pp = &d->next;
 680                 if (src2)
 681                         range_set_union(&d->ranges, &src->ranges, &src2->ranges);
 682                 else
 683                         range_set_copy(&d->ranges, &src->ranges);
 684         }
 685
 686         return head;
 687 }
 688
 689 static void add_line_range(struct rev_info *revs, struct commit *commit,
 690                            struct line_log_data *range)
 691 {
 692         struct line_log_data *old = NULL;
 693         struct line_log_data *new = NULL;
 694
 695         old = lookup_decoration(&revs->line_log_data, &commit->object);
 696         if (old && range) {
 697                 new = line_log_data_merge(old, range);
 698                 free_line_log_data(old);
 699         } else if (range)
 700                 new = line_log_data_copy(range);
 701
 702         if (new)
 703                 add_decoration(&revs->line_log_data, &commit->object, new);
 704 }
 705
 706 static void clear_commit_line_range(struct rev_info *revs, struct commit *commit)
 707 {
 708         struct line_log_data *r;
 709         r = lookup_decoration(&revs->line_log_data, &commit->object);
 710         if (!r)
 711                 return;
 712         free_line_log_data(r);
 713         add_decoration(&revs->line_log_data, &commit->object, NULL);
 714 }
 715
 716 static struct line_log_data *lookup_line_range(struct rev_info *revs,
 717                                                struct commit *commit)
 718 {
 719         struct line_log_data *ret = NULL;
 720         struct line_log_data *d;
 721
 722         ret = lookup_decoration(&revs->line_log_data, &commit->object);
 723
 724         for (d = ret; d; d = d->next)
 725                 range_set_check_invariants(&d->ranges);
 726
 727         return ret;
 728 }
 729
 730 void line_log_init(struct rev_info *rev, const char *prefix, struct string_list *args)
 731 {
 732         struct commit *commit = NULL;
 733         struct line_log_data *range;
 734
 735         commit = check_single_commit(rev);
 736         range = parse_lines(commit, prefix, args);
 737         add_line_range(rev, commit, range);
 738
 739         if (!rev->diffopt.detect_rename) {
 740                 int i, count = 0;
 741                 struct line_log_data *r = range;
 742                 const char **paths;
 743                 while (r) {
 744                         count++;
 745                         r = r->next;
 746                 }
 747                 paths = xmalloc((count+1)*sizeof(char *));
 748                 r = range;
 749                 for (i = 0; i < count; i++) {
 750                         paths[i] = xstrdup(r->path);
 751                         r = r->next;
 752                 }
 753                 paths[count] = NULL;
 754                 init_pathspec(&rev->diffopt.pathspec, paths);
 755                 free(paths);
 756         }
 757 }
 758
 759 static void load_tree_desc(struct tree_desc *desc, void **tree,
 760                            const unsigned char *sha1)
 761 {
 762         unsigned long size;
 763         *tree = read_object_with_reference(sha1, tree_type, &size, NULL);
 764         if (!*tree)
 765                 die("Unable to read tree (%s)", sha1_to_hex(sha1));
 766         init_tree_desc(desc, *tree, size);
 767 }
 768
 769 static int count_parents(struct commit *commit)
 770 {
 771         struct commit_list *parents = commit->parents;
 772         int count = 0;
 773         while (parents) {
 774                 count++;
 775                 parents = parents->next;
 776         }
 777         return count;
 778 }
 779
 780 static void move_diff_queue(struct diff_queue_struct *dst,
 781                             struct diff_queue_struct *src)
 782 {
 783         assert(src != dst);
 784         memcpy(dst, src, sizeof(struct diff_queue_struct));
 785         DIFF_QUEUE_CLEAR(src);
 786 }
 787
 788 static void filter_diffs_for_paths(struct line_log_data *range, int keep_deletions)
 789 {
 790         int i;
 791         struct diff_queue_struct outq;
 792         DIFF_QUEUE_CLEAR(&outq);
 793
 794         for (i = 0; i < diff_queued_diff.nr; i++) {
 795                 struct diff_filepair *p = diff_queued_diff.queue[i];
 796                 struct line_log_data *rg = NULL;
 797
 798                 if (!DIFF_FILE_VALID(p->two)) {
 799                         if (keep_deletions)
 800                                 diff_q(&outq, p);
 801                         else
 802                                 diff_free_filepair(p);
 803                         continue;
 804                 }
 805                 for (rg = range; rg; rg = rg->next) {
 806                         if (!strcmp(rg->path, p->two->path))
 807                                 break;
 808                 }
 809                 if (rg)
 810                         diff_q(&outq, p);
 811                 else
 812                         diff_free_filepair(p);
 813         }
 814         free(diff_queued_diff.queue);
 815         diff_queued_diff = outq;
 816 }
 817
 818 static inline int diff_might_be_rename(void)
 819 {
 820         int i;
 821         for (i = 0; i < diff_queued_diff.nr; i++)
 822                 if (!DIFF_FILE_VALID(diff_queued_diff.queue[i]->one)) {
 823                         /* fprintf(stderr, "diff_might_be_rename found creation of: %s\n", */
 824                         /*      diff_queued_diff.queue[i]->two->path); */
 825                         return 1;
 826                 }
 827         return 0;
 828 }
 829
 830 static void queue_diffs(struct line_log_data *range,
 831                         struct diff_options *opt,
 832                         struct diff_queue_struct *queue,
 833                         struct commit *commit, struct commit *parent)
 834 {
 835         void *tree1 = NULL, *tree2 = NULL;
 836         struct tree_desc desc1, desc2;
 837
 838         assert(commit);
 839         load_tree_desc(&desc2, &tree2, commit->tree->object.sha1);
 840         if (parent)
 841                 load_tree_desc(&desc1, &tree1, parent->tree->object.sha1);
 842         else
 843                 init_tree_desc(&desc1, "", 0);
 844
 845         DIFF_QUEUE_CLEAR(&diff_queued_diff);
 846         diff_tree(&desc1, &desc2, "", opt);
 847         if (opt->detect_rename) {
 848                 filter_diffs_for_paths(range, 1);
 849                 if (diff_might_be_rename())
 850                         diffcore_std(opt);
 851                 filter_diffs_for_paths(range, 0);
 852         }
 853         move_diff_queue(queue, &diff_queued_diff);
 854
 855         if (tree1)
 856                 free(tree1);
 857         if (tree2)
 858                 free(tree2);
 859 }
 860
 861 static char *get_nth_line(long line, unsigned long *ends, void *data)
 862 {
 863         if (line == 0)
 864                 return (char *)data;
 865         else
 866                 return (char *)data + ends[line] + 1;
 867 }
 868
 869 static void print_line(const char *prefix, char first,
 870                        long line, unsigned long *ends, void *data,
 871                        const char *color, const char *reset)
 872 {
 873         char *begin = get_nth_line(line, ends, data);
 874         char *end = get_nth_line(line+1, ends, data);
 875         int had_nl = 0;
 876
 877         if (end > begin && end[-1] == '\n') {
 878                 end--;
 879                 had_nl = 1;
 880         }
 881
 882         fputs(prefix, stdout);
 883         fputs(color, stdout);
 884         putchar(first);
 885         fwrite(begin, 1, end-begin, stdout);
 886         fputs(reset, stdout);
 887         putchar('\n');
 888         if (!had_nl)
 889                 fputs("\\ No newline at end of file\n", stdout);
 890 }
 891
 892 static char *output_prefix(struct diff_options *opt)
 893 {
 894         char *prefix = "";
 895
 896         if (opt->output_prefix) {
 897                 struct strbuf *sb = opt->output_prefix(opt, opt->output_prefix_data);
 898                 prefix = sb->buf;
 899         }
 900
 901         return prefix;
 902 }
 903
 904 static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *range)
 905 {
 906         int i, j = 0;
 907         long p_lines, t_lines;
 908         unsigned long *p_ends = NULL, *t_ends = NULL;
 909         struct diff_filepair *pair = range->pair;
 910         struct diff_ranges *diff = &range->diff;
 911
 912         struct diff_options *opt = &rev->diffopt;
 913         char *prefix = output_prefix(opt);
 914         const char *c_reset = diff_get_color(opt->use_color, DIFF_RESET);
 915         const char *c_frag = diff_get_color(opt->use_color, DIFF_FRAGINFO);
 916         const char *c_meta = diff_get_color(opt->use_color, DIFF_METAINFO);
 917         const char *c_old = diff_get_color(opt->use_color, DIFF_FILE_OLD);
 918         const char *c_new = diff_get_color(opt->use_color, DIFF_FILE_NEW);
 919         const char *c_plain = diff_get_color(opt->use_color, DIFF_PLAIN);
 920
 921         if (!pair || !diff)
 922                 return;
 923
 924         if (pair->one->sha1_valid)
 925                 fill_line_ends(pair->one, &p_lines, &p_ends);
 926         fill_line_ends(pair->two, &t_lines, &t_ends);
 927
 928         printf("%s%sdiff --git a/%s b/%s%s\n", prefix, c_meta, pair->one->path, pair->two->path, c_reset);
 929         printf("%s%s--- %s%s%s\n", prefix, c_meta,
 930                pair->one->sha1_valid ? "a/" : "",
 931                pair->one->sha1_valid ? pair->one->path : "/dev/null",
 932                c_reset);
 933         printf("%s%s+++ b/%s%s\n", prefix, c_meta, pair->two->path, c_reset);
 934         for (i = 0; i < range->ranges.nr; i++) {
 935                 long p_start, p_end;
 936                 long t_start = range->ranges.ranges[i].start;
 937                 long t_end = range->ranges.ranges[i].end;
 938                 long t_cur = t_start;
 939                 int j_last;
 940
 941                 while (j < diff->target.nr && diff->target.ranges[j].end < t_start)
 942                         j++;
 943                 if (j == diff->target.nr || diff->target.ranges[j].start > t_end)
 944                         continue;
 945
 946                 /* Scan ahead to determine the last diff that falls in this range */
 947                 j_last = j;
 948                 while (j_last < diff->target.nr && diff->target.ranges[j_last].start < t_end)
 949                         j_last++;
 950                 if (j_last > j)
 951                         j_last--;
 952
 953                 /*
 954                  * Compute parent hunk headers: we know that the diff
 955                  * has the correct line numbers (but not all hunks).
 956                  * So it suffices to shift the start/end according to
 957                  * the line numbers of the first/last hunk(s) that
 958                  * fall in this range.
 959                  */
 960                 if (t_start < diff->target.ranges[j].start)
 961                         p_start = diff->parent.ranges[j].start - (diff->target.ranges[j].start-t_start);
 962                 else
 963                         p_start = diff->parent.ranges[j].start;
 964                 if (t_end > diff->target.ranges[j_last].end)
 965                         p_end = diff->parent.ranges[j_last].end + (t_end-diff->target.ranges[j_last].end);
 966                 else
 967                         p_end = diff->parent.ranges[j_last].end;
 968
 969                 if (!p_start && !p_end) {
 970                         p_start = -1;
 971                         p_end = -1;
 972                 }
 973
 974                 /* Now output a diff hunk for this range */
 975                 printf("%s%s@@ -%ld,%ld +%ld,%ld @@%s\n",
 976                        prefix, c_frag,
 977                        p_start+1, p_end-p_start, t_start+1, t_end-t_start,
 978                        c_reset);
 979                 while (j < diff->target.nr && diff->target.ranges[j].start < t_end) {
 980                         int k;
 981                         for (; t_cur < diff->target.ranges[j].start; t_cur++)
 982                                 print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
 983                                            c_plain, c_reset);
 984                         for (k = diff->parent.ranges[j].start; k < diff->parent.ranges[j].end; k++)
 985                                 print_line(prefix, '-', k, p_ends, pair->one->data,
 986                                            c_old, c_reset);
 987                         for (; t_cur < diff->target.ranges[j].end && t_cur < t_end; t_cur++)
 988                                 print_line(prefix, '+', t_cur, t_ends, pair->two->data,
 989                                            c_new, c_reset);
 990                         j++;
 991                 }
 992                 for (; t_cur < t_end; t_cur++)
 993                         print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
 994                                    c_plain, c_reset);
 995         }
 996
 997         free(p_ends);
 998         free(t_ends);
 999 }
1000
1001 /*
1002  * NEEDSWORK: manually building a diff here is not the Right
1003  * Thing(tm).  log -L should be built into the diff pipeline.
1004  */
1005 static void dump_diff_hacky(struct rev_info *rev, struct line_log_data *range)
1006 {
1007         puts(output_prefix(&rev->diffopt));
1008         while (range) {
1009                 dump_diff_hacky_one(rev, range);
1010                 range = range->next;
1011         }
1012 }
1013
1014 /*
1015  * Unlike most other functions, this destructively operates on
1016  * 'range'.
1017  */
1018 static int process_diff_filepair(struct rev_info *rev,
1019                                  struct diff_filepair *pair,
1020                                  struct line_log_data *range,
1021                                  struct diff_ranges **diff_out)
1022 {
1023         struct line_log_data *rg = range;
1024         struct range_set tmp;
1025         struct diff_ranges diff;
1026         mmfile_t file_parent, file_target;
1027
1028         assert(pair->two->path);
1029         while (rg) {
1030                 assert(rg->path);
1031                 if (!strcmp(rg->path, pair->two->path))
1032                         break;
1033                 rg = rg->next;
1034         }
1035
1036         if (!rg)
1037                 return 0;
1038         if (rg->ranges.nr == 0)
1039                 return 0;
1040
1041         assert(pair->two->sha1_valid);
1042         diff_populate_filespec(pair->two, 0);
1043         file_target.ptr = pair->two->data;
1044         file_target.size = pair->two->size;
1045
1046         if (pair->one->sha1_valid) {
1047                 diff_populate_filespec(pair->one, 0);
1048                 file_parent.ptr = pair->one->data;
1049                 file_parent.size = pair->one->size;
1050         } else {
1051                 file_parent.ptr = "";
1052                 file_parent.size = 0;
1053         }
1054
1055         diff_ranges_init(&diff);
1056         collect_diff(&file_parent, &file_target, &diff);
1057
1058         /* NEEDSWORK should apply some heuristics to prevent mismatches */
1059         free(rg->path);
1060         rg->path = xstrdup(pair->one->path);
1061
1062         range_set_init(&tmp, 0);
1063         range_set_map_across_diff(&tmp, &rg->ranges, &diff, diff_out);
1064         range_set_release(&rg->ranges);
1065         range_set_move(&rg->ranges, &tmp);
1066
1067         diff_ranges_release(&diff);
1068
1069         return ((*diff_out)->parent.nr > 0);
1070 }
1071
1072 static struct diff_filepair *diff_filepair_dup(struct diff_filepair *pair)
1073 {
1074         struct diff_filepair *new = xmalloc(sizeof(struct diff_filepair));
1075         new->one = pair->one;
1076         new->two = pair->two;
1077         new->one->count++;
1078         new->two->count++;
1079         return new;
1080 }
1081
1082 static void free_diffqueues(int n, struct diff_queue_struct *dq)
1083 {
1084         int i, j;
1085         for (i = 0; i < n; i++)
1086                 for (j = 0; j < dq[i].nr; j++)
1087                         diff_free_filepair(dq[i].queue[j]);
1088         free(dq);
1089 }
1090
1091 static int process_all_files(struct line_log_data **range_out,
1092                              struct rev_info *rev,
1093                              struct diff_queue_struct *queue,
1094                              struct line_log_data *range)
1095 {
1096         int i, changed = 0;
1097
1098         *range_out = line_log_data_copy(range);
1099
1100         for (i = 0; i < queue->nr; i++) {
1101                 struct diff_ranges *pairdiff = NULL;
1102                 struct diff_filepair *pair = queue->queue[i];
1103                 if (process_diff_filepair(rev, pair, *range_out, &pairdiff)) {
1104                         /*
1105                          * Store away the diff for later output.  We
1106                          * tuck it in the ranges we got as _input_,
1107                          * since that's the commit that caused the
1108                          * diff.
1109                          *
1110                          * NEEDSWORK not enough when we get around to
1111                          * doing something interesting with merges;
1112                          * currently each invocation on a merge parent
1113                          * trashes the previous one's diff.
1114                          *
1115                          * NEEDSWORK tramples over data structures not owned here
1116                          */
1117                         struct line_log_data *rg = range;
1118                         changed++;
1119                         while (rg && strcmp(rg->path, pair->two->path))
1120                                 rg = rg->next;
1121                         assert(rg);
1122                         rg->pair = diff_filepair_dup(queue->queue[i]);
1123                         memcpy(&rg->diff, pairdiff, sizeof(struct diff_ranges));
1124                 }
1125         }
1126
1127         return changed;
1128 }
1129
1130 int line_log_print(struct rev_info *rev, struct commit *commit)
1131 {
1132         struct line_log_data *range = lookup_line_range(rev, commit);
1133
1134         show_log(rev);
1135         dump_diff_hacky(rev, range);
1136         return 1;
1137 }
1138
1139 static int process_ranges_ordinary_commit(struct rev_info *rev, struct commit *commit,
1140                                           struct line_log_data *range)
1141 {
1142         struct commit *parent = NULL;
1143         struct diff_queue_struct queue;
1144         struct line_log_data *parent_range;
1145         int changed;
1146
1147         if (commit->parents)
1148                 parent = commit->parents->item;
1149
1150         queue_diffs(range, &rev->diffopt, &queue, commit, parent);
1151         changed = process_all_files(&parent_range, rev, &queue, range);
1152         if (parent)
1153                 add_line_range(rev, parent, parent_range);
1154         return changed;
1155 }
1156
1157 static int process_ranges_merge_commit(struct rev_info *rev, struct commit *commit,
1158                                        struct line_log_data *range)
1159 {
1160         struct diff_queue_struct *diffqueues;
1161         struct line_log_data **cand;
1162         struct commit **parents;
1163         struct commit_list *p;
1164         int i;
1165         int nparents = count_parents(commit);
1166
1167         diffqueues = xmalloc(nparents * sizeof(*diffqueues));
1168         cand = xmalloc(nparents * sizeof(*cand));
1169         parents = xmalloc(nparents * sizeof(*parents));
1170
1171         p = commit->parents;
1172         for (i = 0; i < nparents; i++) {
1173                 parents[i] = p->item;
1174                 p = p->next;
1175                 queue_diffs(range, &rev->diffopt, &diffqueues[i], commit, parents[i]);
1176         }
1177
1178         for (i = 0; i < nparents; i++) {
1179                 int changed;
1180                 cand[i] = NULL;
1181                 changed = process_all_files(&cand[i], rev, &diffqueues[i], range);
1182                 if (!changed) {
1183                         /*
1184                          * This parent can take all the blame, so we
1185                          * don't follow any other path in history
1186                          */
1187                         add_line_range(rev, parents[i], cand[i]);
1188                         clear_commit_line_range(rev, commit);
1189                         commit->parents = xmalloc(sizeof(struct commit_list));
1190                         commit->parents->item = parents[i];
1191                         commit->parents->next = NULL;
1192                         free(parents);
1193                         free(cand);
1194                         free_diffqueues(nparents, diffqueues);
1195                         /* NEEDSWORK leaking like a sieve */
1196                         return 0;
1197                 }
1198         }
1199
1200         /*
1201          * No single parent took the blame.  We add the candidates
1202          * from the above loop to the parents.
1203          */
1204         for (i = 0; i < nparents; i++) {
1205                 add_line_range(rev, parents[i], cand[i]);
1206         }
1207
1208         clear_commit_line_range(rev, commit);
1209         free(parents);
1210         free(cand);
1211         free_diffqueues(nparents, diffqueues);
1212         return 1;
1213
1214         /* NEEDSWORK evil merge detection stuff */
1215         /* NEEDSWORK leaking like a sieve */
1216 }
1217
1218 static int process_ranges_arbitrary_commit(struct rev_info *rev, struct commit *commit)
1219 {
1220         struct line_log_data *range = lookup_line_range(rev, commit);
1221         int changed = 0;
1222
1223         if (range) {
1224                 if (!commit->parents || !commit->parents->next)
1225                         changed = process_ranges_ordinary_commit(rev, commit, range);
1226                 else
1227                         changed = process_ranges_merge_commit(rev, commit, range);
1228         }
1229
1230         if (!changed)
1231                 commit->object.flags |= TREESAME;
1232
1233         return changed;
1234 }
1235
1236 static enum rewrite_result line_log_rewrite_one(struct rev_info *rev, struct commit **pp)
1237 {
1238         for (;;) {
1239                 struct commit *p = *pp;
1240                 if (p->parents && p->parents->next)
1241                         return rewrite_one_ok;
1242                 if (p->object.flags & UNINTERESTING)
1243                         return rewrite_one_ok;
1244                 if (!(p->object.flags & TREESAME))
1245                         return rewrite_one_ok;
1246                 if (!p->parents)
1247                         return rewrite_one_noparents;
1248                 *pp = p->parents->item;
1249         }
1250 }
1251
1252 int line_log_filter(struct rev_info *rev)
1253 {
1254         struct commit *commit;
1255         struct commit_list *list = rev->commits;
1256         struct commit_list *out = NULL, **pp = &out;
1257
1258         while (list) {
1259                 struct commit_list *to_free = NULL;
1260                 commit = list->item;
1261                 if (process_ranges_arbitrary_commit(rev, commit)) {
1262                         *pp = list;
1263                         pp = &list->next;
1264                 } else
1265                         to_free = list;
1266                 list = list->next;
1267                 free(to_free);
1268         }
1269         *pp = NULL;
1270
1271         for (list = out; list; list = list->next)
1272                 rewrite_parents(rev, list->item, line_log_rewrite_one);
1273
1274         rev->commits = out;
1275
1276         return 0;
1277 }