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   1 /*
   2  * rev-parse.c
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7 #include "commit.h"
   8 #include "refs.h"
   9
  10 static char *def = NULL;
  11 static int no_revs = 0;
  12 static int single_rev = 0;
  13 static int revs_only = 0;
  14 static int do_rev_argument = 1;
  15 static int output_revs = 0;
  16 static int flags_only = 0;
  17 static int no_flags = 0;
  18 static int output_sq = 0;
  19
  20 #define NORMAL 0
  21 #define REVERSED 1
  22 static int show_type = NORMAL;
  23
  24 static int get_extended_sha1(char *name, unsigned char *sha1);
  25
  26 /*
  27  * Some arguments are relevant "revision" arguments,
  28  * others are about output format or other details.
  29  * This sorts it all out.
  30  */
  31 static int is_rev_argument(const char *arg)
  32 {
  33         static const char *rev_args[] = {
  34                 "--max-count=",
  35                 "--max-age=",
  36                 "--min-age=",
  37                 "--merge-order",
  38                 NULL
  39         };
  40         const char **p = rev_args;
  41
  42         for (;;) {
  43                 const char *str = *p++;
  44                 int len;
  45                 if (!str)
  46                         return 0;
  47                 len = strlen(str);
  48                 if (!strncmp(arg, str, len))
  49                         return 1;
  50         }
  51 }
  52
  53 static void show(const char *arg)
  54 {
  55         if (output_sq) {
  56                 int sq = '\'', ch;
  57
  58                 putchar(sq);
  59                 while ((ch = *arg++)) {
  60                         if (ch == sq)
  61                                 fputs("'\\'", stdout);
  62                         putchar(ch);
  63                 }
  64                 putchar(sq);
  65                 putchar(' ');
  66         }
  67         else
  68                 puts(arg);
  69 }
  70
  71 static void show_rev(int type, const unsigned char *sha1)
  72 {
  73         if (no_revs)
  74                 return;
  75         output_revs++;
  76
  77         /* Hexadecimal string plus possibly a carret;
  78          * this does not have to be quoted even under output_sq.
  79          */
  80         printf("%s%s%c", type == show_type ? "" : "^", sha1_to_hex(sha1),
  81                output_sq ? ' ' : '\n');
  82 }
  83
  84 static void show_rev_arg(char *rev)
  85 {
  86         if (no_revs)
  87                 return;
  88         show(rev);
  89 }
  90
  91 static void show_norev(char *norev)
  92 {
  93         if (flags_only)
  94                 return;
  95         if (revs_only)
  96                 return;
  97         show(norev);
  98 }
  99
 100 static void show_arg(char *arg)
 101 {
 102         if (no_flags)
 103                 return;
 104         if (do_rev_argument && is_rev_argument(arg))
 105                 show_rev_arg(arg);
 106         else
 107                 show_norev(arg);
 108 }
 109
 110 static int get_parent(char *name, unsigned char *result, int idx)
 111 {
 112         unsigned char sha1[20];
 113         int ret = get_extended_sha1(name, sha1);
 114         struct commit *commit;
 115         struct commit_list *p;
 116
 117         if (ret)
 118                 return ret;
 119         commit = lookup_commit_reference(sha1);
 120         if (!commit)
 121                 return -1;
 122         if (parse_commit(commit))
 123                 return -1;
 124         if (!idx) {
 125                 memcpy(result, commit->object.sha1, 20);
 126                 return 0;
 127         }
 128         p = commit->parents;
 129         while (p) {
 130                 if (!--idx) {
 131                         memcpy(result, p->item->object.sha1, 20);
 132                         return 0;
 133                 }
 134                 p = p->next;
 135         }
 136         return -1;
 137 }
 138
 139 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 140 {
 141         static char dirname[PATH_MAX];
 142         char hex[40];
 143         DIR *dir;
 144         int found;
 145
 146         snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
 147         dir = opendir(dirname);
 148         sprintf(hex, "%.2s", name);
 149         found = 0;
 150         if (dir) {
 151                 struct dirent *de;
 152                 while ((de = readdir(dir)) != NULL) {
 153                         if (strlen(de->d_name) != 38)
 154                                 continue;
 155                         if (memcmp(de->d_name, name + 2, len-2))
 156                                 continue;
 157                         memcpy(hex + 2, de->d_name, 38);
 158                         if (++found > 1)
 159                                 break;
 160                 }
 161                 closedir(dir);
 162         }
 163         if (found == 1)
 164                 return get_sha1_hex(hex, sha1) == 0;
 165         return 0;
 166 }
 167
 168 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 169 {
 170         do {
 171                 if (*a != *b)
 172                         return 0;
 173                 a++;
 174                 b++;
 175                 len -= 2;
 176         } while (len > 1);
 177         if (len)
 178                 if ((*a ^ *b) & 0xf0)
 179                         return 0;
 180         return 1;
 181 }
 182
 183 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
 184 {
 185         struct packed_git *p;
 186
 187         prepare_packed_git();
 188         for (p = packed_git; p; p = p->next) {
 189                 unsigned num = num_packed_objects(p);
 190                 unsigned first = 0, last = num;
 191                 while (first < last) {
 192                         unsigned mid = (first + last) / 2;
 193                         unsigned char now[20];
 194                         int cmp;
 195
 196                         nth_packed_object_sha1(p, mid, now);
 197                         cmp = memcmp(match, now, 20);
 198                         if (!cmp) {
 199                                 first = mid;
 200                                 break;
 201                         }
 202                         if (cmp > 0) {
 203                                 first = mid+1;
 204                                 continue;
 205                         }
 206                         last = mid;
 207                 }
 208                 if (first < num) {
 209                         unsigned char now[20], next[20];
 210                         nth_packed_object_sha1(p, first, now);
 211                         if (match_sha(len, match, now)) {
 212                                 if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
 213                                         memcpy(sha1, now, 20);
 214                                         return 1;
 215                                 }
 216                         }
 217                 }
 218         }
 219         return 0;
 220 }
 221
 222 static int get_short_sha1(char *name, unsigned char *sha1)
 223 {
 224         int i;
 225         char canonical[40];
 226         unsigned char res[20];
 227
 228         memset(res, 0, 20);
 229         memset(canonical, 'x', 40);
 230         for (i = 0;;i++) {
 231                 unsigned char c = name[i];
 232                 unsigned char val;
 233                 if (!c || i > 40)
 234                         break;
 235                 if (c >= '0' && c <= '9')
 236                         val = c - '0';
 237                 else if (c >= 'a' && c <= 'f')
 238                         val = c - 'a' + 10;
 239                 else if (c >= 'A' && c <='F') {
 240                         val = c - 'A' + 10;
 241                         c -= 'A' - 'a';
 242                 }
 243                 else
 244                         return -1;
 245                 canonical[i] = c;
 246                 if (!(i & 1))
 247                         val <<= 4;
 248                 res[i >> 1] |= val;
 249         }
 250         if (i < 4)
 251                 return -1;
 252         if (find_short_object_filename(i, canonical, sha1))
 253                 return 0;
 254         if (find_short_packed_object(i, res, sha1))
 255                 return 0;
 256         return -1;
 257 }
 258
 259 /*
 260  * This is like "get_sha1()", except it allows "sha1 expressions",
 261  * notably "xyz^" for "parent of xyz"
 262  */
 263 static int get_extended_sha1(char *name, unsigned char *sha1)
 264 {
 265         int parent, ret;
 266         int len = strlen(name);
 267
 268         parent = 1;
 269         if (len > 2 && name[len-1] >= '0' && name[len-1] <= '9') {
 270                 parent = name[len-1] - '0';
 271                 len--;
 272         }
 273         if (len > 1 && name[len-1] == '^') {
 274                 name[len-1] = 0;
 275                 ret = get_parent(name, sha1, parent);
 276                 name[len-1] = '^';
 277                 if (!ret)
 278                         return 0;
 279         }
 280         ret = get_sha1(name, sha1);
 281         if (!ret)
 282                 return 0;
 283         return get_short_sha1(name, sha1);
 284 }
 285
 286 static void show_default(void)
 287 {
 288         char *s = def;
 289
 290         if (s) {
 291                 unsigned char sha1[20];
 292
 293                 def = NULL;
 294                 if (!get_extended_sha1(s, sha1)) {
 295                         show_rev(NORMAL, sha1);
 296                         return;
 297                 }
 298                 show_arg(s);
 299         }
 300 }
 301
 302 static int show_reference(const char *refname, const unsigned char *sha1)
 303 {
 304         show_rev(NORMAL, sha1);
 305         return 0;
 306 }
 307
 308 int main(int argc, char **argv)
 309 {
 310         int i, as_is = 0;
 311         unsigned char sha1[20];
 312
 313         for (i = 1; i < argc; i++) {
 314                 char *arg = argv[i];
 315                 char *dotdot;
 316
 317                 if (as_is) {
 318                         show_norev(arg);
 319                         continue;
 320                 }
 321                 if (*arg == '-') {
 322                         if (!strcmp(arg, "--")) {
 323                                 show_default();
 324                                 if (revs_only)
 325                                         break;
 326                                 as_is = 1;
 327                         }
 328                         if (!strcmp(arg, "--default")) {
 329                                 def = argv[i+1];
 330                                 i++;
 331                                 continue;
 332                         }
 333                         if (!strcmp(arg, "--revs-only")) {
 334                                 revs_only = 1;
 335                                 continue;
 336                         }
 337                         if (!strcmp(arg, "--no-revs")) {
 338                                 no_revs = 1;
 339                                 continue;
 340                         }
 341                         if (!strcmp(arg, "--flags")) {
 342                                 flags_only = 1;
 343                                 continue;
 344                         }
 345                         if (!strcmp(arg, "--no-flags")) {
 346                                 no_flags = 1;
 347                                 continue;
 348                         }
 349                         if (!strcmp(arg, "--verify")) {
 350                                 revs_only = 1;
 351                                 do_rev_argument = 0;
 352                                 single_rev = 1;
 353                                 continue;
 354                         }
 355                         if (!strcmp(arg, "--sq")) {
 356                                 output_sq = 1;
 357                                 continue;
 358                         }
 359                         if (!strcmp(arg, "--not")) {
 360                                 show_type ^= REVERSED;
 361                                 continue;
 362                         }
 363                         if (!strcmp(arg, "--all")) {
 364                                 for_each_ref(show_reference);
 365                                 continue;
 366                         }
 367                         show_arg(arg);
 368                         continue;
 369                 }
 370                 dotdot = strstr(arg, "..");
 371                 if (dotdot) {
 372                         unsigned char end[20];
 373                         char *n = dotdot+2;
 374                         *dotdot = 0;
 375                         if (!get_extended_sha1(arg, sha1)) {
 376                                 if (!*n)
 377                                         n = "HEAD";
 378                                 if (!get_extended_sha1(n, end)) {
 379                                         if (no_revs)
 380                                                 continue;
 381                                         def = NULL;
 382                                         show_rev(NORMAL, end);
 383                                         show_rev(REVERSED, sha1);
 384                                         continue;
 385                                 }
 386                         }
 387                         *dotdot = '.';
 388                 }
 389                 if (!get_extended_sha1(arg, sha1)) {
 390                         if (no_revs)
 391                                 continue;
 392                         def = NULL;
 393                         show_rev(NORMAL, sha1);
 394                         continue;
 395                 }
 396                 if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
 397                         if (no_revs)
 398                                 continue;
 399                         def = NULL;
 400                         show_rev(REVERSED, sha1);
 401                         continue;
 402                 }
 403                 show_default();
 404                 show_norev(arg);
 405         }
 406         show_default();
 407         if (single_rev && output_revs != 1) {
 408                 fprintf(stderr, "Needed a single revision\n");
 409                 exit(1);
 410         }
 411         return 0;
 412 }