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         struct object_id oid;
  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, oid.hash, &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(oid.hash, &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(oid.hash, &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_object_file(&oid);
  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, &oid, 1, &buf, &size))
  70                         break;
  71
  72         case 'p':
  73                 type = sha1_object_info(oid.hash, 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, &oid, NULL, 0);
  87                 buf = read_sha1_file(oid.hash, &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                         struct object_id blob_oid;
  97                         if (sha1_object_info(oid.hash, NULL) == OBJ_TAG) {
  98                                 char *buffer = read_sha1_file(oid.hash, &type, &size);
  99                                 const char *target;
 100                                 if (!skip_prefix(buffer, "object ", &target) ||
 101                                     get_oid_hex(target, &blob_oid))
 102                                         die("%s not a valid tag", oid_to_hex(&oid));
 103                                 free(buffer);
 104                         } else
 105                                 oidcpy(&blob_oid, &oid);
 106
 107                         if (sha1_object_info(blob_oid.hash, NULL) == OBJ_BLOB)
 108                                 return stream_blob_to_fd(1, &blob_oid, 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(oid.hash, 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         struct object_id oid;
 132         enum object_type type;
 133         unsigned long size;
 134         off_t disk_size;
 135         const char *rest;
 136         struct object_id delta_base_oid;
 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          * This flag will be true if the requested batch format and options
 160          * don't require us to call sha1_object_info, which can then be
 161          * optimized out.
 162          */
 163         unsigned skip_object_info : 1;
 164 };
 165
 166 static int is_atom(const char *atom, const char *s, int slen)
 167 {
 168         int alen = strlen(atom);
 169         return alen == slen && !memcmp(atom, s, alen);
 170 }
 171
 172 static void expand_atom(struct strbuf *sb, const char *atom, int len,
 173                         void *vdata)
 174 {
 175         struct expand_data *data = vdata;
 176
 177         if (is_atom("objectname", atom, len)) {
 178                 if (!data->mark_query)
 179                         strbuf_addstr(sb, oid_to_hex(&data->oid));
 180         } else if (is_atom("objecttype", atom, len)) {
 181                 if (data->mark_query)
 182                         data->info.typep = &data->type;
 183                 else
 184                         strbuf_addstr(sb, typename(data->type));
 185         } else if (is_atom("objectsize", atom, len)) {
 186                 if (data->mark_query)
 187                         data->info.sizep = &data->size;
 188                 else
 189                         strbuf_addf(sb, "%lu", data->size);
 190         } else if (is_atom("objectsize:disk", atom, len)) {
 191                 if (data->mark_query)
 192                         data->info.disk_sizep = &data->disk_size;
 193                 else
 194                         strbuf_addf(sb, "%"PRIuMAX, (uintmax_t)data->disk_size);
 195         } else if (is_atom("rest", atom, len)) {
 196                 if (data->mark_query)
 197                         data->split_on_whitespace = 1;
 198                 else if (data->rest)
 199                         strbuf_addstr(sb, data->rest);
 200         } else if (is_atom("deltabase", atom, len)) {
 201                 if (data->mark_query)
 202                         data->info.delta_base_sha1 = data->delta_base_oid.hash;
 203                 else
 204                         strbuf_addstr(sb,
 205                                       oid_to_hex(&data->delta_base_oid));
 206         } else
 207                 die("unknown format element: %.*s", len, atom);
 208 }
 209
 210 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 211 {
 212         const char *end;
 213
 214         if (*start != '(')
 215                 return 0;
 216         end = strchr(start + 1, ')');
 217         if (!end)
 218                 die("format element '%s' does not end in ')'", start);
 219
 220         expand_atom(sb, start + 1, end - start - 1, data);
 221
 222         return end - start + 1;
 223 }
 224
 225 static void batch_write(struct batch_options *opt, const void *data, int len)
 226 {
 227         if (opt->buffer_output) {
 228                 if (fwrite(data, 1, len, stdout) != len)
 229                         die_errno("unable to write to stdout");
 230         } else
 231                 write_or_die(1, data, len);
 232 }
 233
 234 static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
 235 {
 236         const struct object_id *oid = &data->oid;
 237
 238         assert(data->info.typep);
 239
 240         if (data->type == OBJ_BLOB) {
 241                 if (opt->buffer_output)
 242                         fflush(stdout);
 243                 if (stream_blob_to_fd(1, oid, NULL, 0) < 0)
 244                         die("unable to stream %s to stdout", oid_to_hex(oid));
 245         }
 246         else {
 247                 enum object_type type;
 248                 unsigned long size;
 249                 void *contents;
 250
 251                 contents = read_sha1_file(oid->hash, &type, &size);
 252                 if (!contents)
 253                         die("object %s disappeared", oid_to_hex(oid));
 254                 if (type != data->type)
 255                         die("object %s changed type!?", oid_to_hex(oid));
 256                 if (data->info.sizep && size != data->size)
 257                         die("object %s changed size!?", oid_to_hex(oid));
 258
 259                 batch_write(opt, contents, size);
 260                 free(contents);
 261         }
 262 }
 263
 264 static void batch_object_write(const char *obj_name, struct batch_options *opt,
 265                                struct expand_data *data)
 266 {
 267         struct strbuf buf = STRBUF_INIT;
 268
 269         if (!data->skip_object_info &&
 270             sha1_object_info_extended(data->oid.hash, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 271                 printf("%s missing\n",
 272                        obj_name ? obj_name : oid_to_hex(&data->oid));
 273                 fflush(stdout);
 274                 return;
 275         }
 276
 277         strbuf_expand(&buf, opt->format, expand_format, data);
 278         strbuf_addch(&buf, '\n');
 279         batch_write(opt, buf.buf, buf.len);
 280         strbuf_release(&buf);
 281
 282         if (opt->print_contents) {
 283                 print_object_or_die(opt, data);
 284                 batch_write(opt, "\n", 1);
 285         }
 286 }
 287
 288 static void batch_one_object(const char *obj_name, struct batch_options *opt,
 289                              struct expand_data *data)
 290 {
 291         struct object_context ctx;
 292         int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 293         enum follow_symlinks_result result;
 294
 295         result = get_sha1_with_context(obj_name, flags, data->oid.hash, &ctx);
 296         if (result != FOUND) {
 297                 switch (result) {
 298                 case MISSING_OBJECT:
 299                         printf("%s missing\n", obj_name);
 300                         break;
 301                 case DANGLING_SYMLINK:
 302                         printf("dangling %"PRIuMAX"\n%s\n",
 303                                (uintmax_t)strlen(obj_name), obj_name);
 304                         break;
 305                 case SYMLINK_LOOP:
 306                         printf("loop %"PRIuMAX"\n%s\n",
 307                                (uintmax_t)strlen(obj_name), obj_name);
 308                         break;
 309                 case NOT_DIR:
 310                         printf("notdir %"PRIuMAX"\n%s\n",
 311                                (uintmax_t)strlen(obj_name), obj_name);
 312                         break;
 313                 default:
 314                         die("BUG: unknown get_sha1_with_context result %d\n",
 315                                result);
 316                         break;
 317                 }
 318                 fflush(stdout);
 319                 return;
 320         }
 321
 322         if (ctx.mode == 0) {
 323                 printf("symlink %"PRIuMAX"\n%s\n",
 324                        (uintmax_t)ctx.symlink_path.len,
 325                        ctx.symlink_path.buf);
 326                 fflush(stdout);
 327                 return;
 328         }
 329
 330         batch_object_write(obj_name, opt, data);
 331 }
 332
 333 struct object_cb_data {
 334         struct batch_options *opt;
 335         struct expand_data *expand;
 336 };
 337
 338 static void batch_object_cb(const unsigned char sha1[20], void *vdata)
 339 {
 340         struct object_cb_data *data = vdata;
 341         hashcpy(data->expand->oid.hash, sha1);
 342         batch_object_write(NULL, data->opt, data->expand);
 343 }
 344
 345 static int batch_loose_object(const unsigned char *sha1,
 346                               const char *path,
 347                               void *data)
 348 {
 349         sha1_array_append(data, sha1);
 350         return 0;
 351 }
 352
 353 static int batch_packed_object(const unsigned char *sha1,
 354                                struct packed_git *pack,
 355                                uint32_t pos,
 356                                void *data)
 357 {
 358         sha1_array_append(data, sha1);
 359         return 0;
 360 }
 361
 362 static int batch_objects(struct batch_options *opt)
 363 {
 364         struct strbuf buf = STRBUF_INIT;
 365         struct expand_data data;
 366         int save_warning;
 367         int retval = 0;
 368
 369         if (!opt->format)
 370                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
 371
 372         /*
 373          * Expand once with our special mark_query flag, which will prime the
 374          * object_info to be handed to sha1_object_info_extended for each
 375          * object.
 376          */
 377         memset(&data, 0, sizeof(data));
 378         data.mark_query = 1;
 379         strbuf_expand(&buf, opt->format, expand_format, &data);
 380         data.mark_query = 0;
 381
 382         if (opt->all_objects) {
 383                 struct object_info empty;
 384                 memset(&empty, 0, sizeof(empty));
 385                 if (!memcmp(&data.info, &empty, sizeof(empty)))
 386                         data.skip_object_info = 1;
 387         }
 388
 389         /*
 390          * If we are printing out the object, then always fill in the type,
 391          * since we will want to decide whether or not to stream.
 392          */
 393         if (opt->print_contents)
 394                 data.info.typep = &data.type;
 395
 396         if (opt->all_objects) {
 397                 struct sha1_array sa = SHA1_ARRAY_INIT;
 398                 struct object_cb_data cb;
 399
 400                 for_each_loose_object(batch_loose_object, &sa, 0);
 401                 for_each_packed_object(batch_packed_object, &sa, 0);
 402
 403                 cb.opt = opt;
 404                 cb.expand = &data;
 405                 sha1_array_for_each_unique(&sa, batch_object_cb, &cb);
 406
 407                 sha1_array_clear(&sa);
 408                 return 0;
 409         }
 410
 411         /*
 412          * We are going to call get_sha1 on a potentially very large number of
 413          * objects. In most large cases, these will be actual object sha1s. The
 414          * cost to double-check that each one is not also a ref (just so we can
 415          * warn) ends up dwarfing the actual cost of the object lookups
 416          * themselves. We can work around it by just turning off the warning.
 417          */
 418         save_warning = warn_on_object_refname_ambiguity;
 419         warn_on_object_refname_ambiguity = 0;
 420
 421         while (strbuf_getline(&buf, stdin) != EOF) {
 422                 if (data.split_on_whitespace) {
 423                         /*
 424                          * Split at first whitespace, tying off the beginning
 425                          * of the string and saving the remainder (or NULL) in
 426                          * data.rest.
 427                          */
 428                         char *p = strpbrk(buf.buf, " \t");
 429                         if (p) {
 430                                 while (*p && strchr(" \t", *p))
 431                                         *p++ = '\0';
 432                         }
 433                         data.rest = p;
 434                 }
 435
 436                 batch_one_object(buf.buf, opt, &data);
 437         }
 438
 439         strbuf_release(&buf);
 440         warn_on_object_refname_ambiguity = save_warning;
 441         return retval;
 442 }
 443
 444 static const char * const cat_file_usage[] = {
 445         N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
 446         N_("git cat-file (--batch | --batch-check) [--follow-symlinks]"),
 447         NULL
 448 };
 449
 450 static int git_cat_file_config(const char *var, const char *value, void *cb)
 451 {
 452         if (userdiff_config(var, value) < 0)
 453                 return -1;
 454
 455         return git_default_config(var, value, cb);
 456 }
 457
 458 static int batch_option_callback(const struct option *opt,
 459                                  const char *arg,
 460                                  int unset)
 461 {
 462         struct batch_options *bo = opt->value;
 463
 464         if (bo->enabled) {
 465                 return 1;
 466         }
 467
 468         bo->enabled = 1;
 469         bo->print_contents = !strcmp(opt->long_name, "batch");
 470         bo->format = arg;
 471
 472         return 0;
 473 }
 474
 475 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 476 {
 477         int opt = 0;
 478         const char *exp_type = NULL, *obj_name = NULL;
 479         struct batch_options batch = {0};
 480         int unknown_type = 0;
 481
 482         const struct option options[] = {
 483                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 484                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 485                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 486                 OPT_CMDMODE('e', NULL, &opt,
 487                             N_("exit with zero when there's no error"), 'e'),
 488                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 489                 OPT_CMDMODE(0, "textconv", &opt,
 490                             N_("for blob objects, run textconv on object's content"), 'c'),
 491                 OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 492                           N_("allow -s and -t to work with broken/corrupt objects")),
 493                 OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
 494                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
 495                         N_("show info and content of objects fed from the standard input"),
 496                         PARSE_OPT_OPTARG, batch_option_callback },
 497                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 498                         N_("show info about objects fed from the standard input"),
 499                         PARSE_OPT_OPTARG, batch_option_callback },
 500                 OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 501                          N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 502                 OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
 503                          N_("show all objects with --batch or --batch-check")),
 504                 OPT_END()
 505         };
 506
 507         git_config(git_cat_file_config, NULL);
 508
 509         batch.buffer_output = -1;
 510         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
 511
 512         if (opt) {
 513                 if (argc == 1)
 514                         obj_name = argv[0];
 515                 else
 516                         usage_with_options(cat_file_usage, options);
 517         }
 518         if (!opt && !batch.enabled) {
 519                 if (argc == 2) {
 520                         exp_type = argv[0];
 521                         obj_name = argv[1];
 522                 } else
 523                         usage_with_options(cat_file_usage, options);
 524         }
 525         if (batch.enabled && (opt || argc)) {
 526                 usage_with_options(cat_file_usage, options);
 527         }
 528
 529         if ((batch.follow_symlinks || batch.all_objects) && !batch.enabled) {
 530                 usage_with_options(cat_file_usage, options);
 531         }
 532
 533         if (batch.buffer_output < 0)
 534                 batch.buffer_output = batch.all_objects;
 535
 536         if (batch.enabled)
 537                 return batch_objects(&batch);
 538
 539         if (unknown_type && opt != 't' && opt != 's')
 540                 die("git cat-file --allow-unknown-type: use with -s or -t");
 541         return cat_one_file(opt, exp_type, obj_name, unknown_type);
 542 }