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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         if (!idx) {
 101                 memcpy(result, commit->object.sha1, 20);
 102                 return 0;
 103         }
 104         p = commit->parents;
 105         while (p) {
 106                 if (!--idx) {
 107                         memcpy(result, p->item->object.sha1, 20);
 108                         return 0;
 109                 }
 110                 p = p->next;
 111         }
 112         return -1;
 113 }
 114
 115 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 116 {
 117         static char dirname[PATH_MAX];
 118         char hex[40];
 119         DIR *dir;
 120         int found;
 121
 122         snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
 123         dir = opendir(dirname);
 124         sprintf(hex, "%.2s", name);
 125         found = 0;
 126         if (dir) {
 127                 struct dirent *de;
 128                 while ((de = readdir(dir)) != NULL) {
 129                         if (strlen(de->d_name) != 38)
 130                                 continue;
 131                         if (memcmp(de->d_name, name + 2, len-2))
 132                                 continue;
 133                         memcpy(hex + 2, de->d_name, 38);
 134                         if (++found > 1)
 135                                 break;
 136                 }
 137                 closedir(dir);
 138         }
 139         if (found == 1)
 140                 return get_sha1_hex(hex, sha1) == 0;
 141         return 0;
 142 }
 143
 144 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 145 {
 146         do {
 147                 if (*a != *b)
 148                         return 0;
 149                 a++;
 150                 b++;
 151                 len -= 2;
 152         } while (len > 1);
 153         if (len)
 154                 if ((*a ^ *b) & 0xf0)
 155                         return 0;
 156         return 1;
 157 }
 158
 159 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
 160 {
 161         struct packed_git *p;
 162
 163         prepare_packed_git();
 164         for (p = packed_git; p; p = p->next) {
 165                 unsigned num = num_packed_objects(p);
 166                 unsigned first = 0, last = num;
 167                 while (first < last) {
 168                         unsigned mid = (first + last) / 2;
 169                         unsigned char now[20];
 170                         int cmp;
 171
 172                         nth_packed_object_sha1(p, mid, now);
 173                         cmp = memcmp(match, now, 20);
 174                         if (!cmp) {
 175                                 first = mid;
 176                                 break;
 177                         }
 178                         if (cmp > 0) {
 179                                 first = mid+1;
 180                                 continue;
 181                         }
 182                         last = mid;
 183                 }
 184                 if (first < num) {
 185                         unsigned char now[20], next[20];
 186                         nth_packed_object_sha1(p, first, now);
 187                         if (match_sha(len, match, now)) {
 188                                 if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
 189                                         memcpy(sha1, now, 20);
 190                                         return 1;
 191                                 }
 192                         }
 193                 }
 194         }
 195         return 0;
 196 }
 197
 198 static int get_short_sha1(char *name, unsigned char *sha1)
 199 {
 200         int i;
 201         char canonical[40];
 202         unsigned char res[20];
 203
 204         memset(res, 0, 20);
 205         memset(canonical, 'x', 40);
 206         for (i = 0;;i++) {
 207                 unsigned char c = name[i];
 208                 unsigned char val;
 209                 if (!c || i > 40)
 210                         break;
 211                 if (c >= '0' && c <= '9')
 212                         val = c - '0';
 213                 else if (c >= 'a' && c <= 'f')
 214                         val = c - 'a' + 10;
 215                 else if (c >= 'A' && c <='F') {
 216                         val = c - 'A' + 10;
 217                         c -= 'A' - 'a';
 218                 }
 219                 else
 220                         return -1;
 221                 canonical[i] = c;
 222                 if (!(i & 1))
 223                         val <<= 4;
 224                 res[i >> 1] |= val;
 225         }
 226         if (i < 4)
 227                 return -1;
 228         if (find_short_object_filename(i, canonical, sha1))
 229                 return 0;
 230         if (find_short_packed_object(i, res, sha1))
 231                 return 0;
 232         return -1;
 233 }
 234
 235 /*
 236  * This is like "get_sha1()", except it allows "sha1 expressions",
 237  * notably "xyz^" for "parent of xyz"
 238  */
 239 static int get_extended_sha1(char *name, unsigned char *sha1)
 240 {
 241         int parent, ret;
 242         int len = strlen(name);
 243
 244         parent = 1;
 245         if (len > 2 && name[len-1] >= '0' && name[len-1] <= '9') {
 246                 parent = name[len-1] - '0';
 247                 len--;
 248         }
 249         if (len > 1 && name[len-1] == '^') {
 250                 name[len-1] = 0;
 251                 ret = get_parent(name, sha1, parent);
 252                 name[len-1] = '^';
 253                 if (!ret)
 254                         return 0;
 255         }
 256         ret = get_sha1(name, sha1);
 257         if (!ret)
 258                 return 0;
 259         return get_short_sha1(name, sha1);
 260 }
 261
 262 static void show_default(void)
 263 {
 264         char *s = def;
 265
 266         if (s) {
 267                 unsigned char sha1[20];
 268
 269                 def = NULL;
 270                 if (!get_extended_sha1(s, sha1)) {
 271                         show_rev(NORMAL, sha1);
 272                         return;
 273                 }
 274                 show_arg(s);
 275         }
 276 }
 277
 278 static int show_reference(const char *refname, const unsigned char *sha1)
 279 {
 280         show_rev(NORMAL, sha1);
 281         return 0;
 282 }
 283
 284 int main(int argc, char **argv)
 285 {
 286         int i, as_is = 0;
 287         unsigned char sha1[20];
 288
 289         for (i = 1; i < argc; i++) {
 290                 char *arg = argv[i];
 291                 char *dotdot;
 292
 293                 if (as_is) {
 294                         show_norev(arg);
 295                         continue;
 296                 }
 297                 if (*arg == '-') {
 298                         if (!strcmp(arg, "--")) {
 299                                 show_default();
 300                                 if (revs_only)
 301                                         break;
 302                                 as_is = 1;
 303                         }
 304                         if (!strcmp(arg, "--default")) {
 305                                 def = argv[i+1];
 306                                 i++;
 307                                 continue;
 308                         }
 309                         if (!strcmp(arg, "--revs-only")) {
 310                                 revs_only = 1;
 311                                 continue;
 312                         }
 313                         if (!strcmp(arg, "--no-revs")) {
 314                                 no_revs = 1;
 315                                 continue;
 316                         }
 317                         if (!strcmp(arg, "--flags")) {
 318                                 flags_only = 1;
 319                                 continue;
 320                         }
 321                         if (!strcmp(arg, "--no-flags")) {
 322                                 no_flags = 1;
 323                                 continue;
 324                         }
 325                         if (!strcmp(arg, "--verify")) {
 326                                 revs_only = 1;
 327                                 do_rev_argument = 0;
 328                                 single_rev = 1;
 329                                 continue;
 330                         }
 331                         if (!strcmp(arg, "--not")) {
 332                                 show_type ^= REVERSED;
 333                                 continue;
 334                         }
 335                         if (!strcmp(arg, "--all")) {
 336                                 for_each_ref(show_reference);
 337                                 continue;
 338                         }
 339                         show_arg(arg);
 340                         continue;
 341                 }
 342                 dotdot = strstr(arg, "..");
 343                 if (dotdot) {
 344                         unsigned char end[20];
 345                         char *n = dotdot+2;
 346                         *dotdot = 0;
 347                         if (!get_extended_sha1(arg, sha1)) {
 348                                 if (!*n)
 349                                         n = "HEAD";
 350                                 if (!get_extended_sha1(n, end)) {
 351                                         if (no_revs)
 352                                                 continue;
 353                                         def = NULL;
 354                                         show_rev(NORMAL, end);
 355                                         show_rev(REVERSED, sha1);
 356                                         continue;
 357                                 }
 358                         }
 359                         *dotdot = '.';
 360                 }
 361                 if (!get_extended_sha1(arg, sha1)) {
 362                         if (no_revs)
 363                                 continue;
 364                         def = NULL;
 365                         show_rev(NORMAL, sha1);
 366                         continue;
 367                 }
 368                 if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
 369                         if (no_revs)
 370                                 continue;
 371                         def = NULL;
 372                         show_rev(REVERSED, sha1);
 373                         continue;
 374                 }
 375                 show_default();
 376                 show_norev(arg);
 377         }
 378         show_default();
 379         if (single_rev && output_revs != 1) {
 380                 fprintf(stderr, "Needed a single revision\n");
 381                 exit(1);
 382         }
 383         return 0;
 384 }