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