combine-diff.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "diff.h"
   4 #include "diffcore.h"
   5 #include "quote.h"
   6
   7 struct path_list {
   8         struct path_list *next;
   9         int len;
  10         char *path;
  11         unsigned char sha1[20];
  12         unsigned char parent_sha1[FLEX_ARRAY][20];
  13 };
  14
  15 static int uninteresting(struct diff_filepair *p)
  16 {
  17         if (diff_unmodified_pair(p))
  18                 return 1;
  19         if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
  20                 return 1;
  21         return 0;
  22 }
  23
  24 static struct path_list *intersect_paths(struct path_list *curr,
  25                                          int n, int num_parent)
  26 {
  27         struct diff_queue_struct *q = &diff_queued_diff;
  28         struct path_list *p;
  29         int i;
  30
  31         if (!n) {
  32                 struct path_list *list = NULL, *tail = NULL;
  33                 for (i = 0; i < q->nr; i++) {
  34                         int len;
  35                         const char *path;
  36                         if (uninteresting(q->queue[i]))
  37                                 continue;
  38                         path = q->queue[i]->two->path;
  39                         len = strlen(path);
  40
  41                         p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
  42                         p->path = (char*) &(p->parent_sha1[num_parent][0]);
  43                         memcpy(p->path, path, len);
  44                         p->path[len] = 0;
  45                         p->len = len;
  46                         p->next = NULL;
  47                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  48                         memcpy(p->parent_sha1[n], q->queue[i]->one->sha1, 20);
  49                         if (!tail)
  50                                 list = tail = p;
  51                         else {
  52                                 tail->next = p;
  53                                 p = tail;
  54                         }
  55                 }
  56                 return list;
  57         }
  58
  59         for (p = curr; p; p = p->next) {
  60                 int found = 0;
  61                 if (!p->len)
  62                         continue;
  63                 for (i = 0; i < q->nr; i++) {
  64                         const char *path;
  65                         int len;
  66
  67                         if (uninteresting(q->queue[i]))
  68                                 continue;
  69                         path = q->queue[i]->two->path;
  70                         len = strlen(path);
  71                         if (len == p->len && !memcmp(path, p->path, len)) {
  72                                 found = 1;
  73                                 memcpy(p->parent_sha1[n],
  74                                        q->queue[i]->one->sha1, 20);
  75                                 break;
  76                         }
  77                 }
  78                 if (!found)
  79                         p->len = 0;
  80         }
  81         return curr;
  82 }
  83
  84 struct lline {
  85         struct lline *next;
  86         int len;
  87         unsigned long parent_map;
  88         char line[FLEX_ARRAY];
  89 };
  90
  91 struct sline {
  92         struct lline *lost_head, **lost_tail;
  93         char *bol;
  94         int len;
  95         unsigned long flag;
  96 };
  97
  98 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  99 {
 100         char *blob;
 101         char type[20];
 102         if (!memcmp(sha1, null_sha1, 20)) {
 103                 /* deleted blob */
 104                 *size = 0;
 105                 return xcalloc(1, 1);
 106         }
 107         blob = read_sha1_file(sha1, type, size);
 108         if (strcmp(type, "blob"))
 109                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 110         return blob;
 111 }
 112
 113 #define TMPPATHLEN 50
 114 #define MAXLINELEN 10240
 115
 116 static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
 117 {
 118         int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
 119         if (fd < 0)
 120                 die("unable to create temp-file");
 121         if (write(fd, blob, size) != size)
 122                 die("unable to write temp-file");
 123         close(fd);
 124 }
 125
 126 static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
 127 {
 128         unsigned long size;
 129         void *blob;
 130         blob = grab_blob(sha1, &size);
 131         write_to_temp_file(tmpfile, blob, size);
 132         free(blob);
 133 }
 134
 135 static int parse_num(char **cp_p, unsigned int *num_p)
 136 {
 137         char *cp = *cp_p;
 138         unsigned int num = 0;
 139         int read_some;
 140
 141         while ('0' <= *cp && *cp <= '9')
 142                 num = num * 10 + *cp++ - '0';
 143         if (!(read_some = cp - *cp_p))
 144                 return -1;
 145         *cp_p = cp;
 146         *num_p = num;
 147         return 0;
 148 }
 149
 150 static int parse_hunk_header(char *line, int len,
 151                              unsigned int *ob, unsigned int *on,
 152                              unsigned int *nb, unsigned int *nn)
 153 {
 154         char *cp;
 155         cp = line + 4;
 156         if (parse_num(&cp, ob)) {
 157         bad_line:
 158                 return error("malformed diff output: %s", line);
 159         }
 160         if (*cp == ',') {
 161                 cp++;
 162                 if (parse_num(&cp, on))
 163                         goto bad_line;
 164         }
 165         else
 166                 *on = 1;
 167         if (*cp++ != ' ' || *cp++ != '+')
 168                 goto bad_line;
 169         if (parse_num(&cp, nb))
 170                 goto bad_line;
 171         if (*cp == ',') {
 172                 cp++;
 173                 if (parse_num(&cp, nn))
 174                         goto bad_line;
 175         }
 176         else
 177                 *nn = 1;
 178         return -!!memcmp(cp, " @@", 3);
 179 }
 180
 181 static void append_lost(struct sline *sline, int n, const char *line)
 182 {
 183         struct lline *lline;
 184         int len = strlen(line);
 185         unsigned long this_mask = (1UL<<n);
 186         if (line[len-1] == '\n')
 187                 len--;
 188
 189         /* Check to see if we can squash things */
 190         if (sline->lost_head) {
 191                 struct lline *last_one = NULL;
 192                 /* We cannot squash it with earlier one */
 193                 for (lline = sline->lost_head;
 194                      lline;
 195                      lline = lline->next)
 196                         if (lline->parent_map & this_mask)
 197                                 last_one = lline;
 198                 lline = last_one ? last_one->next : sline->lost_head;
 199                 while (lline) {
 200                         if (lline->len == len &&
 201                             !memcmp(lline->line, line, len)) {
 202                                 lline->parent_map |= this_mask;
 203                                 return;
 204                         }
 205                         lline = lline->next;
 206                 }
 207         }
 208
 209         lline = xmalloc(sizeof(*lline) + len + 1);
 210         lline->len = len;
 211         lline->next = NULL;
 212         lline->parent_map = this_mask;
 213         memcpy(lline->line, line, len);
 214         lline->line[len] = 0;
 215         if (sline->lost_head)
 216                 *(sline->lost_tail) = lline;
 217         else
 218                 sline->lost_head = lline;
 219         sline->lost_tail = &lline->next;
 220 }
 221
 222 static void combine_diff(const unsigned char *parent, const char *ourtmp,
 223                          struct sline *sline, int cnt, int n)
 224 {
 225         FILE *in;
 226         char parent_tmp[TMPPATHLEN];
 227         char cmd[TMPPATHLEN * 2 + 1024];
 228         char line[MAXLINELEN];
 229         unsigned int lno, ob, on, nb, nn;
 230         unsigned long pmask = ~(1UL << n);
 231         struct sline *lost_bucket = NULL;
 232
 233         write_temp_blob(parent_tmp, parent);
 234         sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
 235                 parent_tmp, ourtmp);
 236         in = popen(cmd, "r");
 237         if (!in)
 238                 return;
 239
 240         lno = 1;
 241         while (fgets(line, sizeof(line), in) != NULL) {
 242                 int len = strlen(line);
 243                 if (5 < len && !memcmp("@@ -", line, 4)) {
 244                         if (parse_hunk_header(line, len,
 245                                               &ob, &on, &nb, &nn))
 246                                 break;
 247                         lno = nb;
 248                         if (!nb) {
 249                                 /* @@ -1,2 +0,0 @@ to remove the
 250                                  * first two lines...
 251                                  */
 252                                 nb = 1;
 253                         }
 254                         lost_bucket = &sline[nb-1]; /* sline is 0 based */
 255                         continue;
 256                 }
 257                 if (!lost_bucket)
 258                         continue;
 259                 switch (line[0]) {
 260                 case '-':
 261                         append_lost(lost_bucket, n, line+1);
 262                         break;
 263                 case '+':
 264                         sline[lno-1].flag &= pmask;
 265                         lno++;
 266                         break;
 267                 }
 268         }
 269         fclose(in);
 270         unlink(parent_tmp);
 271 }
 272
 273 static unsigned long context = 3;
 274 static char combine_marker = '@';
 275
 276 static int interesting(struct sline *sline, unsigned long all_mask)
 277 {
 278         return ((sline->flag & all_mask) != all_mask || sline->lost_head);
 279 }
 280
 281 static void make_hunks(struct sline *sline, unsigned long cnt, int num_parent)
 282 {
 283         unsigned long all_mask = (1UL<<num_parent) - 1;
 284         unsigned long mark = (1UL<<num_parent);
 285         unsigned long i;
 286
 287         i = 0;
 288         while (i < cnt) {
 289                 if (interesting(&sline[i], all_mask)) {
 290                         unsigned long j = (context < i) ? i - context : 0;
 291                         while (j <= i)
 292                                 sline[j++].flag |= mark;
 293                         while (++i < cnt) {
 294                                 if (!interesting(&sline[i], all_mask))
 295                                         break;
 296                                 sline[i].flag |= mark;
 297                         }
 298                         j = (i + context < cnt) ? i + context : cnt;
 299                         while (i < j)
 300                                 sline[i++].flag |= mark;
 301                         continue;
 302                 }
 303                 i++;
 304         }
 305 }
 306
 307 static void dump_sline(struct sline *sline, int cnt, int num_parent)
 308 {
 309         unsigned long mark = (1UL<<num_parent);
 310         int i;
 311         int lno = 0;
 312
 313         while (1) {
 314                 struct sline *sl = &sline[lno];
 315                 int hunk_end;
 316                 while (lno < cnt && !(sline[lno].flag & mark))
 317                         lno++;
 318                 if (cnt <= lno)
 319                         break;
 320                 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 321                         if (!(sline[hunk_end].flag & mark))
 322                                 break;
 323                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 324                 printf(" +%d,%d ", lno+1, hunk_end-lno);
 325                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 326                 putchar('\n');
 327                 while (lno < hunk_end) {
 328                         struct lline *ll;
 329                         int j;
 330                         sl = &sline[lno++];
 331                         ll = sl->lost_head;
 332                         while (ll) {
 333                                 for (j = 0; j < num_parent; j++) {
 334                                         if (ll->parent_map & (1UL<<j))
 335                                                 putchar('-');
 336                                         else
 337                                                 putchar(' ');
 338                                 }
 339                                 putchar(' ');
 340                                 puts(ll->line);
 341                                 ll = ll->next;
 342                         }
 343                         for (j = 0; j < num_parent; j++) {
 344                                 if ((1UL<<j) & sl->flag)
 345                                         putchar(' ');
 346                                 else
 347                                         putchar('+');
 348                         }
 349                         printf(" %.*s\n", sl->len, sl->bol);
 350                 }
 351         }
 352 }
 353
 354 static void show_combined_diff(struct path_list *elem, int num_parent)
 355 {
 356         unsigned long size, cnt, lno;
 357         char *result, *cp, *ep;
 358         struct sline *sline; /* survived lines */
 359         int i;
 360         char ourtmp[TMPPATHLEN];
 361
 362         /* Read the result of merge first */
 363         result = grab_blob(elem->sha1, &size);
 364         write_to_temp_file(ourtmp, result, size);
 365
 366         for (cnt = 0, cp = result; cp - result < size; cp++) {
 367                 if (*cp == '\n')
 368                         cnt++;
 369         }
 370         if (result[size-1] != '\n')
 371                 cnt++; /* incomplete line */
 372
 373         sline = xcalloc(cnt, sizeof(*sline));
 374         ep = result;
 375         sline[0].bol = result;
 376         for (lno = 0, cp = result; cp - result < size; cp++) {
 377                 if (*cp == '\n') {
 378                         sline[lno].len = cp - sline[lno].bol;
 379                         sline[lno].flag = (1UL<<num_parent) - 1;
 380                         lno++;
 381                         if (lno < cnt)
 382                                 sline[lno].bol = cp + 1;
 383                 }
 384         }
 385         if (result[size-1] != '\n') {
 386                 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
 387                 sline[cnt-1].flag = (1UL<<num_parent) - 1;
 388         }
 389
 390         for (i = 0; i < num_parent; i++)
 391                 combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
 392
 393         make_hunks(sline, cnt, num_parent);
 394
 395         dump_sline(sline, cnt, num_parent);
 396         unlink(ourtmp);
 397         free(result);
 398
 399         for (i = 0; i < cnt; i++) {
 400                 if (sline[i].lost_head) {
 401                         struct lline *ll = sline[i].lost_head;
 402                         while (ll) {
 403                                 struct lline *tmp = ll;
 404                                 ll = ll->next;
 405                                 free(tmp);
 406                         }
 407                 }
 408         }
 409         free(sline);
 410 }
 411
 412 int diff_tree_combined_merge(const unsigned char *sha1,
 413                              const char *header, int show_empty_merge)
 414 {
 415         struct commit *commit = lookup_commit(sha1);
 416         struct diff_options diffopts;
 417         struct commit_list *parents;
 418         struct path_list *p, *paths = NULL;
 419         int num_parent, i, num_paths;
 420
 421         diff_setup(&diffopts);
 422         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 423         diffopts.recursive = 1;
 424
 425         /* count parents */
 426         for (parents = commit->parents, num_parent = 0;
 427              parents;
 428              parents = parents->next, num_parent++)
 429                 ; /* nothing */
 430
 431         /* find set of paths that everybody touches */
 432         for (parents = commit->parents, i = 0;
 433              parents;
 434              parents = parents->next, i++) {
 435                 struct commit *parent = parents->item;
 436                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 437                                &diffopts);
 438                 paths = intersect_paths(paths, i, num_parent);
 439                 diff_flush(&diffopts);
 440         }
 441
 442         /* find out surviving paths */
 443         for (num_paths = 0, p = paths; p; p = p->next) {
 444                 if (p->len)
 445                         num_paths++;
 446         }
 447         if (num_paths || show_empty_merge) {
 448                 puts(header);
 449                 for (p = paths; p; p = p->next) {
 450                         if (!p->len)
 451                                 continue;
 452                         printf("diff --combined ");
 453                         if (quote_c_style(p->path, NULL, NULL, 0))
 454                                 quote_c_style(p->path, NULL, stdout, 0);
 455                         else
 456                                 printf("%s", p->path);
 457                         putchar('\n');
 458                         show_combined_diff(p, num_parent);
 459                 }
 460         }
 461
 462         /* Clean things up */
 463         while (paths) {
 464                 struct path_list *tmp = paths;
 465                 paths = paths->next;
 466                 free(tmp);
 467         }
 468         return 0;
 469 }