builtin/cat-file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7 #include "builtin.h"
   8 #include "parse-options.h"
   9 #include "userdiff.h"
  10 #include "streaming.h"
  11 #include "tree-walk.h"
  12 #include "sha1-array.h"
  13
  14 struct batch_options {
  15         int enabled;
  16         int follow_symlinks;
  17         int print_contents;
  18         int buffer_output;
  19         int all_objects;
  20         const char *format;
  21 };
  22
  23 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
  24                         int unknown_type)
  25 {
  26         unsigned char sha1[20];
  27         enum object_type type;
  28         char *buf;
  29         unsigned long size;
  30         struct object_context obj_context;
  31         struct object_info oi = {NULL};
  32         struct strbuf sb = STRBUF_INIT;
  33         unsigned flags = LOOKUP_REPLACE_OBJECT;
  34
  35         if (unknown_type)
  36                 flags |= LOOKUP_UNKNOWN_OBJECT;
  37
  38         if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
  39                 die("Not a valid object name %s", obj_name);
  40
  41         buf = NULL;
  42         switch (opt) {
  43         case 't':
  44                 oi.typename = &sb;
  45                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  46                         die("git cat-file: could not get object info");
  47                 if (sb.len) {
  48                         printf("%s\n", sb.buf);
  49                         strbuf_release(&sb);
  50                         return 0;
  51                 }
  52                 break;
  53
  54         case 's':
  55                 oi.sizep = &size;
  56                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  57                         die("git cat-file: could not get object info");
  58                 printf("%lu\n", size);
  59                 return 0;
  60
  61         case 'e':
  62                 return !has_sha1_file(sha1);
  63
  64         case 'c':
  65                 if (!obj_context.path[0])
  66                         die("git cat-file --textconv %s: <object> must be <sha1:path>",
  67                             obj_name);
  68
  69                 if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
  70                         break;
  71
  72         case 'p':
  73                 type = sha1_object_info(sha1, NULL);
  74                 if (type < 0)
  75                         die("Not a valid object name %s", obj_name);
  76
  77                 /* custom pretty-print here */
  78                 if (type == OBJ_TREE) {
  79                         const char *ls_args[3] = { NULL };
  80                         ls_args[0] =  "ls-tree";
  81                         ls_args[1] =  obj_name;
  82                         return cmd_ls_tree(2, ls_args, NULL);
  83                 }
  84
  85                 if (type == OBJ_BLOB)
  86                         return stream_blob_to_fd(1, sha1, NULL, 0);
  87                 buf = read_sha1_file(sha1, &type, &size);
  88                 if (!buf)
  89                         die("Cannot read object %s", obj_name);
  90
  91                 /* otherwise just spit out the data */
  92                 break;
  93
  94         case 0:
  95                 if (type_from_string(exp_type) == OBJ_BLOB) {
  96                         unsigned char blob_sha1[20];
  97                         if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
  98                                 char *buffer = read_sha1_file(sha1, &type, &size);
  99                                 const char *target;
 100                                 if (!skip_prefix(buffer, "object ", &target) ||
 101                                     get_sha1_hex(target, blob_sha1))
 102                                         die("%s not a valid tag", sha1_to_hex(sha1));
 103                                 free(buffer);
 104                         } else
 105                                 hashcpy(blob_sha1, sha1);
 106
 107                         if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
 108                                 return stream_blob_to_fd(1, blob_sha1, NULL, 0);
 109                         /*
 110                          * we attempted to dereference a tag to a blob
 111                          * and failed; there may be new dereference
 112                          * mechanisms this code is not aware of.
 113                          * fall-back to the usual case.
 114                          */
 115                 }
 116                 buf = read_object_with_reference(sha1, exp_type, &size, NULL);
 117                 break;
 118
 119         default:
 120                 die("git cat-file: unknown option: %s", exp_type);
 121         }
 122
 123         if (!buf)
 124                 die("git cat-file %s: bad file", obj_name);
 125
 126         write_or_die(1, buf, size);
 127         return 0;
 128 }
 129
 130 struct expand_data {
 131         unsigned char sha1[20];
 132         enum object_type type;
 133         unsigned long size;
 134         unsigned long disk_size;
 135         const char *rest;
 136         unsigned char delta_base_sha1[20];
 137
 138         /*
 139          * If mark_query is true, we do not expand anything, but rather
 140          * just mark the object_info with items we wish to query.
 141          */
 142         int mark_query;
 143
 144         /*
 145          * Whether to split the input on whitespace before feeding it to
 146          * get_sha1; this is decided during the mark_query phase based on
 147          * whether we have a %(rest) token in our format.
 148          */
 149         int split_on_whitespace;
 150
 151         /*
 152          * After a mark_query run, this object_info is set up to be
 153          * passed to sha1_object_info_extended. It will point to the data
 154          * elements above, so you can retrieve the response from there.
 155          */
 156         struct object_info info;
 157 };
 158
 159 static int is_atom(const char *atom, const char *s, int slen)
 160 {
 161         int alen = strlen(atom);
 162         return alen == slen && !memcmp(atom, s, alen);
 163 }
 164
 165 static void expand_atom(struct strbuf *sb, const char *atom, int len,
 166                         void *vdata)
 167 {
 168         struct expand_data *data = vdata;
 169
 170         if (is_atom("objectname", atom, len)) {
 171                 if (!data->mark_query)
 172                         strbuf_addstr(sb, sha1_to_hex(data->sha1));
 173         } else if (is_atom("objecttype", atom, len)) {
 174                 if (data->mark_query)
 175                         data->info.typep = &data->type;
 176                 else
 177                         strbuf_addstr(sb, typename(data->type));
 178         } else if (is_atom("objectsize", atom, len)) {
 179                 if (data->mark_query)
 180                         data->info.sizep = &data->size;
 181                 else
 182                         strbuf_addf(sb, "%lu", data->size);
 183         } else if (is_atom("objectsize:disk", atom, len)) {
 184                 if (data->mark_query)
 185                         data->info.disk_sizep = &data->disk_size;
 186                 else
 187                         strbuf_addf(sb, "%lu", data->disk_size);
 188         } else if (is_atom("rest", atom, len)) {
 189                 if (data->mark_query)
 190                         data->split_on_whitespace = 1;
 191                 else if (data->rest)
 192                         strbuf_addstr(sb, data->rest);
 193         } else if (is_atom("deltabase", atom, len)) {
 194                 if (data->mark_query)
 195                         data->info.delta_base_sha1 = data->delta_base_sha1;
 196                 else
 197                         strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
 198         } else
 199                 die("unknown format element: %.*s", len, atom);
 200 }
 201
 202 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 203 {
 204         const char *end;
 205
 206         if (*start != '(')
 207                 return 0;
 208         end = strchr(start + 1, ')');
 209         if (!end)
 210                 die("format element '%s' does not end in ')'", start);
 211
 212         expand_atom(sb, start + 1, end - start - 1, data);
 213
 214         return end - start + 1;
 215 }
 216
 217 static void batch_write(struct batch_options *opt, const void *data, int len)
 218 {
 219         if (opt->buffer_output) {
 220                 if (fwrite(data, 1, len, stdout) != len)
 221                         die_errno("unable to write to stdout");
 222         } else
 223                 write_or_die(1, data, len);
 224 }
 225
 226 static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
 227 {
 228         const unsigned char *sha1 = data->sha1;
 229
 230         assert(data->info.typep);
 231
 232         if (data->type == OBJ_BLOB) {
 233                 if (opt->buffer_output)
 234                         fflush(stdout);
 235                 if (stream_blob_to_fd(1, sha1, NULL, 0) < 0)
 236                         die("unable to stream %s to stdout", sha1_to_hex(sha1));
 237         }
 238         else {
 239                 enum object_type type;
 240                 unsigned long size;
 241                 void *contents;
 242
 243                 contents = read_sha1_file(sha1, &type, &size);
 244                 if (!contents)
 245                         die("object %s disappeared", sha1_to_hex(sha1));
 246                 if (type != data->type)
 247                         die("object %s changed type!?", sha1_to_hex(sha1));
 248                 if (data->info.sizep && size != data->size)
 249                         die("object %s changed size!?", sha1_to_hex(sha1));
 250
 251                 batch_write(opt, contents, size);
 252                 free(contents);
 253         }
 254 }
 255
 256 static void batch_object_write(const char *obj_name, struct batch_options *opt,
 257                                struct expand_data *data)
 258 {
 259         struct strbuf buf = STRBUF_INIT;
 260
 261         if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 262                 printf("%s missing\n", obj_name ? obj_name : sha1_to_hex(data->sha1));
 263                 fflush(stdout);
 264                 return;
 265         }
 266
 267         strbuf_expand(&buf, opt->format, expand_format, data);
 268         strbuf_addch(&buf, '\n');
 269         batch_write(opt, buf.buf, buf.len);
 270         strbuf_release(&buf);
 271
 272         if (opt->print_contents) {
 273                 print_object_or_die(opt, data);
 274                 batch_write(opt, "\n", 1);
 275         }
 276 }
 277
 278 static void batch_one_object(const char *obj_name, struct batch_options *opt,
 279                              struct expand_data *data)
 280 {
 281         struct object_context ctx;
 282         int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 283         enum follow_symlinks_result result;
 284
 285         result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
 286         if (result != FOUND) {
 287                 switch (result) {
 288                 case MISSING_OBJECT:
 289                         printf("%s missing\n", obj_name);
 290                         break;
 291                 case DANGLING_SYMLINK:
 292                         printf("dangling %"PRIuMAX"\n%s\n",
 293                                (uintmax_t)strlen(obj_name), obj_name);
 294                         break;
 295                 case SYMLINK_LOOP:
 296                         printf("loop %"PRIuMAX"\n%s\n",
 297                                (uintmax_t)strlen(obj_name), obj_name);
 298                         break;
 299                 case NOT_DIR:
 300                         printf("notdir %"PRIuMAX"\n%s\n",
 301                                (uintmax_t)strlen(obj_name), obj_name);
 302                         break;
 303                 default:
 304                         die("BUG: unknown get_sha1_with_context result %d\n",
 305                                result);
 306                         break;
 307                 }
 308                 fflush(stdout);
 309                 return;
 310         }
 311
 312         if (ctx.mode == 0) {
 313                 printf("symlink %"PRIuMAX"\n%s\n",
 314                        (uintmax_t)ctx.symlink_path.len,
 315                        ctx.symlink_path.buf);
 316                 fflush(stdout);
 317                 return;
 318         }
 319
 320         batch_object_write(obj_name, opt, data);
 321 }
 322
 323 struct object_cb_data {
 324         struct batch_options *opt;
 325         struct expand_data *expand;
 326 };
 327
 328 static void batch_object_cb(const unsigned char sha1[20], void *vdata)
 329 {
 330         struct object_cb_data *data = vdata;
 331         hashcpy(data->expand->sha1, sha1);
 332         batch_object_write(NULL, data->opt, data->expand);
 333 }
 334
 335 static int batch_loose_object(const unsigned char *sha1,
 336                               const char *path,
 337                               void *data)
 338 {
 339         sha1_array_append(data, sha1);
 340         return 0;
 341 }
 342
 343 static int batch_packed_object(const unsigned char *sha1,
 344                                struct packed_git *pack,
 345                                uint32_t pos,
 346                                void *data)
 347 {
 348         sha1_array_append(data, sha1);
 349         return 0;
 350 }
 351
 352 static int batch_objects(struct batch_options *opt)
 353 {
 354         struct strbuf buf = STRBUF_INIT;
 355         struct expand_data data;
 356         int save_warning;
 357         int retval = 0;
 358
 359         if (!opt->format)
 360                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
 361
 362         /*
 363          * Expand once with our special mark_query flag, which will prime the
 364          * object_info to be handed to sha1_object_info_extended for each
 365          * object.
 366          */
 367         memset(&data, 0, sizeof(data));
 368         data.mark_query = 1;
 369         strbuf_expand(&buf, opt->format, expand_format, &data);
 370         data.mark_query = 0;
 371
 372         /*
 373          * If we are printing out the object, then always fill in the type,
 374          * since we will want to decide whether or not to stream.
 375          */
 376         if (opt->print_contents)
 377                 data.info.typep = &data.type;
 378
 379         if (opt->all_objects) {
 380                 struct sha1_array sa = SHA1_ARRAY_INIT;
 381                 struct object_cb_data cb;
 382
 383                 for_each_loose_object(batch_loose_object, &sa, 0);
 384                 for_each_packed_object(batch_packed_object, &sa, 0);
 385
 386                 cb.opt = opt;
 387                 cb.expand = &data;
 388                 sha1_array_for_each_unique(&sa, batch_object_cb, &cb);
 389
 390                 sha1_array_clear(&sa);
 391                 return 0;
 392         }
 393
 394         /*
 395          * We are going to call get_sha1 on a potentially very large number of
 396          * objects. In most large cases, these will be actual object sha1s. The
 397          * cost to double-check that each one is not also a ref (just so we can
 398          * warn) ends up dwarfing the actual cost of the object lookups
 399          * themselves. We can work around it by just turning off the warning.
 400          */
 401         save_warning = warn_on_object_refname_ambiguity;
 402         warn_on_object_refname_ambiguity = 0;
 403
 404         while (strbuf_getline(&buf, stdin, '\n') != EOF) {
 405                 if (data.split_on_whitespace) {
 406                         /*
 407                          * Split at first whitespace, tying off the beginning
 408                          * of the string and saving the remainder (or NULL) in
 409                          * data.rest.
 410                          */
 411                         char *p = strpbrk(buf.buf, " \t");
 412                         if (p) {
 413                                 while (*p && strchr(" \t", *p))
 414                                         *p++ = '\0';
 415                         }
 416                         data.rest = p;
 417                 }
 418
 419                 batch_one_object(buf.buf, opt, &data);
 420         }
 421
 422         strbuf_release(&buf);
 423         warn_on_object_refname_ambiguity = save_warning;
 424         return retval;
 425 }
 426
 427 static const char * const cat_file_usage[] = {
 428         N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
 429         N_("git cat-file (--batch | --batch-check) [--follow-symlinks] < <list-of-objects>"),
 430         NULL
 431 };
 432
 433 static int git_cat_file_config(const char *var, const char *value, void *cb)
 434 {
 435         if (userdiff_config(var, value) < 0)
 436                 return -1;
 437
 438         return git_default_config(var, value, cb);
 439 }
 440
 441 static int batch_option_callback(const struct option *opt,
 442                                  const char *arg,
 443                                  int unset)
 444 {
 445         struct batch_options *bo = opt->value;
 446
 447         if (bo->enabled) {
 448                 return 1;
 449         }
 450
 451         bo->enabled = 1;
 452         bo->print_contents = !strcmp(opt->long_name, "batch");
 453         bo->format = arg;
 454
 455         return 0;
 456 }
 457
 458 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 459 {
 460         int opt = 0;
 461         const char *exp_type = NULL, *obj_name = NULL;
 462         struct batch_options batch = {0};
 463         int unknown_type = 0;
 464
 465         const struct option options[] = {
 466                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 467                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 468                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 469                 OPT_CMDMODE('e', NULL, &opt,
 470                             N_("exit with zero when there's no error"), 'e'),
 471                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 472                 OPT_CMDMODE(0, "textconv", &opt,
 473                             N_("for blob objects, run textconv on object's content"), 'c'),
 474                 OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 475                           N_("allow -s and -t to work with broken/corrupt objects")),
 476                 OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
 477                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
 478                         N_("show info and content of objects fed from the standard input"),
 479                         PARSE_OPT_OPTARG, batch_option_callback },
 480                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 481                         N_("show info about objects fed from the standard input"),
 482                         PARSE_OPT_OPTARG, batch_option_callback },
 483                 OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 484                          N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 485                 OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
 486                          N_("show all objects with --batch or --batch-check")),
 487                 OPT_END()
 488         };
 489
 490         git_config(git_cat_file_config, NULL);
 491
 492         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
 493
 494         if (opt) {
 495                 if (argc == 1)
 496                         obj_name = argv[0];
 497                 else
 498                         usage_with_options(cat_file_usage, options);
 499         }
 500         if (!opt && !batch.enabled) {
 501                 if (argc == 2) {
 502                         exp_type = argv[0];
 503                         obj_name = argv[1];
 504                 } else
 505                         usage_with_options(cat_file_usage, options);
 506         }
 507         if (batch.enabled && (opt || argc)) {
 508                 usage_with_options(cat_file_usage, options);
 509         }
 510
 511         if ((batch.follow_symlinks || batch.all_objects) && !batch.enabled) {
 512                 usage_with_options(cat_file_usage, options);
 513         }
 514
 515         if (batch.enabled)
 516                 return batch_objects(&batch);
 517
 518         if (unknown_type && opt != 't' && opt != 's')
 519                 die("git cat-file --allow-unknown-type: use with -s or -t");
 520         return cat_one_file(opt, exp_type, obj_name, unknown_type);
 521 }