blame.c

   1 #include <assert.h>
   2
   3 #include "cache.h"
   4 #include "refs.h"
   5 #include "tag.h"
   6 #include "commit.h"
   7 #include "tree.h"
   8 #include "blob.h"
   9 #include "diff.h"
  10
  11 #define DEBUG 0
  12
  13 struct commit** blame_lines;
  14 int num_blame_lines;
  15
  16 struct util_info
  17 {
  18     int* line_map;
  19     int num_lines;
  20     unsigned char sha1[20]; /* blob sha, not commit! */
  21     char* buf;
  22     unsigned long size;
  23 //    const char* path;
  24 };
  25
  26 struct chunk
  27 {
  28     int off1, len1; // ---
  29     int off2, len2; // +++
  30 };
  31
  32 struct patch
  33 {
  34     struct chunk* chunks;
  35     int num;
  36 };
  37
  38 static void get_blob(struct commit* commit);
  39
  40 int num_get_patch = 0;
  41 int num_commits = 0;
  42
  43 struct patch* get_patch(struct commit* commit, struct commit* other)
  44 {
  45     struct patch* ret = xmalloc(sizeof(struct patch));
  46     ret->chunks = NULL;
  47     ret->num = 0;
  48
  49     struct util_info* info_c = (struct util_info*) commit->object.util;
  50     struct util_info* info_o = (struct util_info*) other->object.util;
  51
  52     if(!memcmp(info_c->sha1, info_o->sha1, 20))
  53         return ret;
  54
  55     get_blob(commit);
  56     get_blob(other);
  57
  58     FILE* fout = fopen("/tmp/git-blame-tmp1", "w");
  59     if(!fout)
  60         die("fopen tmp1 failed: %s", strerror(errno));
  61
  62     if(fwrite(info_c->buf, info_c->size, 1, fout) != 1)
  63         die("fwrite 1 failed: %s", strerror(errno));
  64     fclose(fout);
  65
  66     fout = fopen("/tmp/git-blame-tmp2", "w");
  67     if(!fout)
  68         die("fopen tmp2 failed: %s", strerror(errno));
  69
  70     if(fwrite(info_o->buf, info_o->size, 1, fout) != 1)
  71         die("fwrite 2 failed: %s", strerror(errno));
  72     fclose(fout);
  73
  74     FILE* fin = popen("diff -u0 /tmp/git-blame-tmp1 /tmp/git-blame-tmp2", "r");
  75     if(!fin)
  76         die("popen failed: %s", strerror(errno));
  77
  78     char buf[1024];
  79     while(fgets(buf, sizeof(buf), fin)) {
  80         if(buf[0] != '@' || buf[1] != '@')
  81             continue;
  82
  83         if(DEBUG)
  84             printf("chunk line: %s", buf);
  85         ret->num++;
  86         ret->chunks = xrealloc(ret->chunks, sizeof(struct chunk)*ret->num);
  87         struct chunk* chunk = &ret->chunks[ret->num-1];
  88
  89         assert(!strncmp(buf, "@@ -", 4));
  90
  91         char* start = buf+4;
  92         char* sp = index(start, ' ');
  93         *sp = '\0';
  94         if(index(start, ',')) {
  95             int ret = sscanf(start, "%d,%d", &chunk->off1, &chunk->len1);
  96             assert(ret == 2);
  97         } else {
  98             int ret = sscanf(start, "%d", &chunk->off1);
  99             assert(ret == 1);
 100             chunk->len1 = 1;
 101         }
 102         *sp = ' ';
 103
 104         start = sp+1;
 105         sp = index(start, ' ');
 106         *sp = '\0';
 107         if(index(start, ',')) {
 108             int ret = sscanf(start, "%d,%d", &chunk->off2, &chunk->len2);
 109             assert(ret == 2);
 110         } else {
 111             int ret = sscanf(start, "%d", &chunk->off2);
 112             assert(ret == 1);
 113             chunk->len2 = 1;
 114         }
 115         *sp = ' ';
 116
 117         if(chunk->off1 > 0)
 118             chunk->off1 -= 1;
 119         if(chunk->off2 > 0)
 120             chunk->off2 -= 1;
 121
 122         assert(chunk->off1 >= 0);
 123         assert(chunk->off2 >= 0);
 124     }
 125     fclose(fin);
 126
 127     num_get_patch++;
 128     return ret;
 129 }
 130
 131 void free_patch(struct patch* p)
 132 {
 133     free(p->chunks);
 134     free(p);
 135 }
 136
 137 static int get_blob_sha1_internal(unsigned char *sha1, const char *base, int baselen,
 138                                   const char *pathname, unsigned mode, int stage);
 139
 140
 141 static unsigned char blob_sha1[20];
 142 static int get_blob_sha1(struct tree* t, const char* pathname, unsigned char* sha1)
 143 {
 144     const char *pathspec[2];
 145     pathspec[0] = pathname;
 146     pathspec[1] = NULL;
 147     memset(blob_sha1, 0, sizeof(blob_sha1));
 148     read_tree_recursive(t, "", 0, 0, pathspec, get_blob_sha1_internal);
 149
 150     int i;
 151     for(i = 0; i < 20; i++) {
 152         if(blob_sha1[i] != 0)
 153             break;
 154     }
 155
 156     if(i == 20)
 157         return -1;
 158
 159     memcpy(sha1, blob_sha1, 20);
 160     return 0;
 161 }
 162
 163 static int get_blob_sha1_internal(unsigned char *sha1, const char *base, int baselen,
 164                                   const char *pathname, unsigned mode, int stage)
 165 {
 166 //    printf("Got blob: %s base: '%s' baselen: %d pathname: '%s' mode: %o stage: %d\n",
 167 //           sha1_to_hex(sha1), base, baselen, pathname, mode, stage);
 168
 169     if(S_ISDIR(mode))
 170         return READ_TREE_RECURSIVE;
 171
 172     memcpy(blob_sha1, sha1, 20);
 173     return -1;
 174 }
 175
 176 static void get_blob(struct commit* commit)
 177 {
 178     struct util_info* info = commit->object.util;
 179     char type[20];
 180
 181     if(info->buf)
 182         return;
 183
 184     info->buf = read_sha1_file(info->sha1, type, &info->size);
 185     assert(!strcmp(type, "blob"));
 186 }
 187
 188 void print_patch(struct patch* p)
 189 {
 190     printf("Num chunks: %d\n", p->num);
 191     int i;
 192     for(i = 0; i < p->num; i++) {
 193         printf("%d,%d %d,%d\n", p->chunks[i].off1, p->chunks[i].len1, p->chunks[i].off2, p->chunks[i].len2);
 194     }
 195 }
 196
 197
 198 // p is a patch from commit to other.
 199 void fill_line_map(struct commit* commit, struct commit* other, struct patch* p)
 200 {
 201     int num_lines = ((struct util_info*) commit->object.util)->num_lines;
 202     int* line_map = ((struct util_info*) commit->object.util)->line_map;
 203     int num_lines2 = ((struct util_info*) other->object.util)->num_lines;
 204     int* line_map2 = ((struct util_info*) other->object.util)->line_map;
 205     int cur_chunk = 0;
 206     int i1, i2;
 207
 208     if(p->num && DEBUG)
 209         print_patch(p);
 210
 211     for(i1 = 0; i1 < num_lines; i1++)
 212         line_map[i1] = -1;
 213
 214     if(DEBUG)
 215         printf("num lines 1: %d num lines 2: %d\n", num_lines, num_lines2);
 216
 217     for(i1 = 0, i2 = 0; i1 < num_lines; i1++, i2++) {
 218         if(DEBUG > 1)
 219             printf("%d %d\n", i1, i2);
 220
 221         if(i2 >= num_lines2)
 222             break;
 223
 224         line_map[i1] = line_map2[i2];
 225
 226         struct chunk* chunk = NULL;
 227         if(cur_chunk < p->num)
 228             chunk = &p->chunks[cur_chunk];
 229
 230         if(chunk && chunk->off1 == i1) {
 231             i2 = chunk->off2;
 232
 233             if(chunk->len1 > 0)
 234                 i1 += chunk->len1-1;
 235             if(chunk->len2 > 0)
 236                 i2 += chunk->len2-1;
 237             cur_chunk++;
 238         }
 239     }
 240 }
 241
 242 int map_line(struct commit* commit, int line)
 243 {
 244     struct util_info* info = commit->object.util;
 245     assert(line >= 0 && line < info->num_lines);
 246     return info->line_map[line];
 247 }
 248
 249 int fill_util_info(struct commit* commit, const char* path)
 250 {
 251     if(commit->object.util)
 252         return 0;
 253
 254     struct util_info* util = xmalloc(sizeof(struct util_info));
 255     util->buf = NULL;
 256     util->size = 0;
 257     util->num_lines = -1;
 258     util->line_map = NULL;
 259
 260     commit->object.util = util;
 261
 262     if(get_blob_sha1(commit->tree, path, util->sha1))
 263         return -1;
 264
 265     return 0;
 266 }
 267
 268 void alloc_line_map(struct commit* commit)
 269 {
 270     struct util_info* util = commit->object.util;
 271
 272     if(util->line_map)
 273         return;
 274
 275     get_blob(commit);
 276
 277     int i;
 278     util->num_lines = 0;
 279     for(i = 0; i < util->size; i++) {
 280         if(util->buf[i] == '\n')
 281             util->num_lines++;
 282     }
 283     util->line_map = xmalloc(sizeof(int)*util->num_lines);
 284 }
 285
 286 void copy_line_map(struct commit* dst, struct commit* src)
 287 {
 288     struct util_info* u_dst = dst->object.util;
 289     struct util_info* u_src = src->object.util;
 290
 291     u_dst->line_map = u_src->line_map;
 292     u_dst->num_lines = u_src->num_lines;
 293     u_dst->buf = u_src->buf;
 294     u_dst->size = u_src->size;
 295 }
 296
 297 void process_commits(struct commit_list* list, const char* path)
 298 {
 299     int i;
 300
 301     while(list) {
 302         struct commit* commit = pop_commit(&list);
 303         struct commit_list* parents;
 304         struct util_info* info;
 305
 306         info = commit->object.util;
 307         num_commits++;
 308         if(DEBUG)
 309             printf("\nProcessing commit: %d %s\n", num_commits, sha1_to_hex(commit->object.sha1));
 310         for(parents = commit->parents;
 311             parents != NULL; parents = parents->next) {
 312             struct commit* parent = parents->item;
 313
 314             if(parse_commit(parent) < 0)
 315                 die("parse_commit error");
 316
 317             if(DEBUG)
 318                 printf("parent: %s\n", sha1_to_hex(parent->object.sha1));
 319
 320             if(fill_util_info(parent, path))
 321                 continue;
 322
 323             // Temporarily assign everything to the parent.
 324             int num_blame = 0;
 325             for(i = 0; i < num_blame_lines; i++) {
 326                 if(blame_lines[i] == commit) {
 327                     num_blame++;
 328                     blame_lines[i] = parent;
 329                 }
 330             }
 331
 332             if(num_blame == 0)
 333                 continue;
 334
 335             struct patch* patch = get_patch(parent, commit);
 336             if(patch->num == 0) {
 337                 copy_line_map(parent, commit);
 338             } else {
 339                 alloc_line_map(parent);
 340                 fill_line_map(parent, commit, patch);
 341             }
 342
 343             for(i = 0; i < patch->num; i++) {
 344                 int l;
 345                 for(l = 0; l < patch->chunks[i].len2; l++) {
 346                     int mapped_line = map_line(commit, patch->chunks[i].off2 + l);
 347                     if(mapped_line != -1 && blame_lines[mapped_line] == parent)
 348                         blame_lines[mapped_line] = commit;
 349                 }
 350             }
 351             free_patch(patch);
 352         }
 353     }
 354 }
 355
 356 #define SEEN 1
 357 struct commit_list* get_commit_list(struct commit* commit, const char* pathname)
 358 {
 359     struct commit_list* ret = NULL;
 360     struct commit_list* process = NULL;
 361     unsigned char sha1[20];
 362
 363     commit_list_insert(commit, &process);
 364
 365     while(process) {
 366         struct commit* com = pop_commit(&process);
 367         if(com->object.flags & SEEN)
 368             continue;
 369
 370         com->object.flags |= SEEN;
 371         commit_list_insert(com, &ret);
 372         struct commit_list* parents;
 373
 374         parse_commit(com);
 375
 376         for(parents = com->parents;
 377             parents != NULL; parents = parents->next) {
 378             struct commit* parent = parents->item;
 379
 380             parse_commit(parent);
 381
 382             if(!get_blob_sha1(parent->tree, pathname, sha1))
 383                 commit_list_insert(parent, &process);
 384         }
 385     }
 386
 387     return ret;
 388 }
 389
 390 int main(int argc, const char **argv)
 391 {
 392     unsigned char sha1[20];
 393     struct commit *commit;
 394     const char* filename;
 395     int i;
 396
 397     setup_git_directory();
 398
 399     if (argc != 3)
 400         die("Usage: blame commit-ish file");
 401
 402     if (get_sha1(argv[1], sha1))
 403         die("get_sha1 failed");
 404
 405     commit = lookup_commit_reference(sha1);
 406
 407     filename = argv[2];
 408
 409     struct commit_list* list = get_commit_list(commit, filename);
 410     sort_in_topological_order(&list, 1);
 411
 412     if(fill_util_info(commit, filename)) {
 413         printf("%s not found in %s\n", filename, argv[1]);
 414         return 0;
 415     }
 416     alloc_line_map(commit);
 417
 418     struct util_info* util = commit->object.util;
 419     num_blame_lines = util->num_lines;
 420     blame_lines = xmalloc(sizeof(struct commit*)*num_blame_lines);
 421
 422
 423     for(i = 0; i < num_blame_lines; i++) {
 424         blame_lines[i] = commit;
 425
 426         ((struct util_info*) commit->object.util)->line_map[i] = i;
 427     }
 428
 429     process_commits(list, filename);
 430
 431     for(i = 0; i < num_blame_lines; i++) {
 432         printf("%d %s\n", i+1-1, sha1_to_hex(blame_lines[i]->object.sha1));
 433 //        printf("%d %s\n", i+1-1, find_unique_abbrev(blame_lines[i]->object.sha1, 6));
 434     }
 435
 436     if(DEBUG) {
 437         printf("num get patch: %d\n", num_get_patch);
 438         printf("num commits: %d\n", num_commits);
 439     }
 440
 441     return 0;
 442 }