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