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 "diff.h"
   9 #include "parse-options.h"
  10 #include "userdiff.h"
  11 #include "streaming.h"
  12 #include "tree-walk.h"
  13 #include "sha1-array.h"
  14
  15 struct batch_options {
  16         int enabled;
  17         int follow_symlinks;
  18         int print_contents;
  19         int buffer_output;
  20         int all_objects;
  21         int cmdmode; /* may be 'w' or 'c' for --filters or --textconv */
  22         const char *format;
  23 };
  24
  25 static const char *force_path;
  26
  27 static int filter_object(const char *path, unsigned mode,
  28                          const struct object_id *oid,
  29                          char **buf, unsigned long *size)
  30 {
  31         enum object_type type;
  32
  33         *buf = read_sha1_file(oid->hash, &type, size);
  34         if (!*buf)
  35                 return error(_("cannot read object %s '%s'"),
  36                              oid_to_hex(oid), path);
  37         if ((type == OBJ_BLOB) && S_ISREG(mode)) {
  38                 struct strbuf strbuf = STRBUF_INIT;
  39                 if (convert_to_working_tree(path, *buf, *size, &strbuf)) {
  40                         free(*buf);
  41                         *size = strbuf.len;
  42                         *buf = strbuf_detach(&strbuf, NULL);
  43                 }
  44         }
  45
  46         return 0;
  47 }
  48
  49 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
  50                         int unknown_type)
  51 {
  52         struct object_id oid;
  53         enum object_type type;
  54         char *buf;
  55         unsigned long size;
  56         struct object_context obj_context;
  57         struct object_info oi = OBJECT_INFO_INIT;
  58         struct strbuf sb = STRBUF_INIT;
  59         unsigned flags = LOOKUP_REPLACE_OBJECT;
  60         const char *path = force_path;
  61
  62         if (unknown_type)
  63                 flags |= LOOKUP_UNKNOWN_OBJECT;
  64
  65         if (get_sha1_with_context(obj_name, GET_SHA1_RECORD_PATH,
  66                                   oid.hash, &obj_context))
  67                 die("Not a valid object name %s", obj_name);
  68
  69         if (!path)
  70                 path = obj_context.path;
  71         if (obj_context.mode == S_IFINVALID)
  72                 obj_context.mode = 0100644;
  73
  74         buf = NULL;
  75         switch (opt) {
  76         case 't':
  77                 oi.typename = &sb;
  78                 if (sha1_object_info_extended(oid.hash, &oi, flags) < 0)
  79                         die("git cat-file: could not get object info");
  80                 if (sb.len) {
  81                         printf("%s\n", sb.buf);
  82                         strbuf_release(&sb);
  83                         return 0;
  84                 }
  85                 break;
  86
  87         case 's':
  88                 oi.sizep = &size;
  89                 if (sha1_object_info_extended(oid.hash, &oi, flags) < 0)
  90                         die("git cat-file: could not get object info");
  91                 printf("%lu\n", size);
  92                 return 0;
  93
  94         case 'e':
  95                 return !has_object_file(&oid);
  96
  97         case 'w':
  98                 if (!path[0])
  99                         die("git cat-file --filters %s: <object> must be "
 100                             "<sha1:path>", obj_name);
 101
 102                 if (filter_object(path, obj_context.mode,
 103                                   &oid, &buf, &size))
 104                         return -1;
 105                 break;
 106
 107         case 'c':
 108                 if (!path[0])
 109                         die("git cat-file --textconv %s: <object> must be <sha1:path>",
 110                             obj_name);
 111
 112                 if (textconv_object(path, obj_context.mode, &oid, 1, &buf, &size))
 113                         break;
 114
 115         case 'p':
 116                 type = sha1_object_info(oid.hash, NULL);
 117                 if (type < 0)
 118                         die("Not a valid object name %s", obj_name);
 119
 120                 /* custom pretty-print here */
 121                 if (type == OBJ_TREE) {
 122                         const char *ls_args[3] = { NULL };
 123                         ls_args[0] =  "ls-tree";
 124                         ls_args[1] =  obj_name;
 125                         return cmd_ls_tree(2, ls_args, NULL);
 126                 }
 127
 128                 if (type == OBJ_BLOB)
 129                         return stream_blob_to_fd(1, &oid, NULL, 0);
 130                 buf = read_sha1_file(oid.hash, &type, &size);
 131                 if (!buf)
 132                         die("Cannot read object %s", obj_name);
 133
 134                 /* otherwise just spit out the data */
 135                 break;
 136
 137         case 0:
 138                 if (type_from_string(exp_type) == OBJ_BLOB) {
 139                         struct object_id blob_oid;
 140                         if (sha1_object_info(oid.hash, NULL) == OBJ_TAG) {
 141                                 char *buffer = read_sha1_file(oid.hash, &type, &size);
 142                                 const char *target;
 143                                 if (!skip_prefix(buffer, "object ", &target) ||
 144                                     get_oid_hex(target, &blob_oid))
 145                                         die("%s not a valid tag", oid_to_hex(&oid));
 146                                 free(buffer);
 147                         } else
 148                                 oidcpy(&blob_oid, &oid);
 149
 150                         if (sha1_object_info(blob_oid.hash, NULL) == OBJ_BLOB)
 151                                 return stream_blob_to_fd(1, &blob_oid, NULL, 0);
 152                         /*
 153                          * we attempted to dereference a tag to a blob
 154                          * and failed; there may be new dereference
 155                          * mechanisms this code is not aware of.
 156                          * fall-back to the usual case.
 157                          */
 158                 }
 159                 buf = read_object_with_reference(oid.hash, exp_type, &size, NULL);
 160                 break;
 161
 162         default:
 163                 die("git cat-file: unknown option: %s", exp_type);
 164         }
 165
 166         if (!buf)
 167                 die("git cat-file %s: bad file", obj_name);
 168
 169         write_or_die(1, buf, size);
 170         free(buf);
 171         free(obj_context.path);
 172         return 0;
 173 }
 174
 175 struct expand_data {
 176         struct object_id oid;
 177         enum object_type type;
 178         unsigned long size;
 179         off_t disk_size;
 180         const char *rest;
 181         struct object_id delta_base_oid;
 182
 183         /*
 184          * If mark_query is true, we do not expand anything, but rather
 185          * just mark the object_info with items we wish to query.
 186          */
 187         int mark_query;
 188
 189         /*
 190          * Whether to split the input on whitespace before feeding it to
 191          * get_sha1; this is decided during the mark_query phase based on
 192          * whether we have a %(rest) token in our format.
 193          */
 194         int split_on_whitespace;
 195
 196         /*
 197          * After a mark_query run, this object_info is set up to be
 198          * passed to sha1_object_info_extended. It will point to the data
 199          * elements above, so you can retrieve the response from there.
 200          */
 201         struct object_info info;
 202
 203         /*
 204          * This flag will be true if the requested batch format and options
 205          * don't require us to call sha1_object_info, which can then be
 206          * optimized out.
 207          */
 208         unsigned skip_object_info : 1;
 209 };
 210
 211 static int is_atom(const char *atom, const char *s, int slen)
 212 {
 213         int alen = strlen(atom);
 214         return alen == slen && !memcmp(atom, s, alen);
 215 }
 216
 217 static void expand_atom(struct strbuf *sb, const char *atom, int len,
 218                         void *vdata)
 219 {
 220         struct expand_data *data = vdata;
 221
 222         if (is_atom("objectname", atom, len)) {
 223                 if (!data->mark_query)
 224                         strbuf_addstr(sb, oid_to_hex(&data->oid));
 225         } else if (is_atom("objecttype", atom, len)) {
 226                 if (data->mark_query)
 227                         data->info.typep = &data->type;
 228                 else
 229                         strbuf_addstr(sb, typename(data->type));
 230         } else if (is_atom("objectsize", atom, len)) {
 231                 if (data->mark_query)
 232                         data->info.sizep = &data->size;
 233                 else
 234                         strbuf_addf(sb, "%lu", data->size);
 235         } else if (is_atom("objectsize:disk", atom, len)) {
 236                 if (data->mark_query)
 237                         data->info.disk_sizep = &data->disk_size;
 238                 else
 239                         strbuf_addf(sb, "%"PRIuMAX, (uintmax_t)data->disk_size);
 240         } else if (is_atom("rest", atom, len)) {
 241                 if (data->mark_query)
 242                         data->split_on_whitespace = 1;
 243                 else if (data->rest)
 244                         strbuf_addstr(sb, data->rest);
 245         } else if (is_atom("deltabase", atom, len)) {
 246                 if (data->mark_query)
 247                         data->info.delta_base_sha1 = data->delta_base_oid.hash;
 248                 else
 249                         strbuf_addstr(sb,
 250                                       oid_to_hex(&data->delta_base_oid));
 251         } else
 252                 die("unknown format element: %.*s", len, atom);
 253 }
 254
 255 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 256 {
 257         const char *end;
 258
 259         if (*start != '(')
 260                 return 0;
 261         end = strchr(start + 1, ')');
 262         if (!end)
 263                 die("format element '%s' does not end in ')'", start);
 264
 265         expand_atom(sb, start + 1, end - start - 1, data);
 266
 267         return end - start + 1;
 268 }
 269
 270 static void batch_write(struct batch_options *opt, const void *data, int len)
 271 {
 272         if (opt->buffer_output) {
 273                 if (fwrite(data, 1, len, stdout) != len)
 274                         die_errno("unable to write to stdout");
 275         } else
 276                 write_or_die(1, data, len);
 277 }
 278
 279 static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
 280 {
 281         const struct object_id *oid = &data->oid;
 282
 283         assert(data->info.typep);
 284
 285         if (data->type == OBJ_BLOB) {
 286                 if (opt->buffer_output)
 287                         fflush(stdout);
 288                 if (opt->cmdmode) {
 289                         char *contents;
 290                         unsigned long size;
 291
 292                         if (!data->rest)
 293                                 die("missing path for '%s'", oid_to_hex(oid));
 294
 295                         if (opt->cmdmode == 'w') {
 296                                 if (filter_object(data->rest, 0100644, oid,
 297                                                   &contents, &size))
 298                                         die("could not convert '%s' %s",
 299                                             oid_to_hex(oid), data->rest);
 300                         } else if (opt->cmdmode == 'c') {
 301                                 enum object_type type;
 302                                 if (!textconv_object(data->rest, 0100644, oid,
 303                                                      1, &contents, &size))
 304                                         contents = read_sha1_file(oid->hash, &type,
 305                                                                   &size);
 306                                 if (!contents)
 307                                         die("could not convert '%s' %s",
 308                                             oid_to_hex(oid), data->rest);
 309                         } else
 310                                 die("BUG: invalid cmdmode: %c", opt->cmdmode);
 311                         batch_write(opt, contents, size);
 312                         free(contents);
 313                 } else if (stream_blob_to_fd(1, oid, NULL, 0) < 0)
 314                         die("unable to stream %s to stdout", oid_to_hex(oid));
 315         }
 316         else {
 317                 enum object_type type;
 318                 unsigned long size;
 319                 void *contents;
 320
 321                 contents = read_sha1_file(oid->hash, &type, &size);
 322                 if (!contents)
 323                         die("object %s disappeared", oid_to_hex(oid));
 324                 if (type != data->type)
 325                         die("object %s changed type!?", oid_to_hex(oid));
 326                 if (data->info.sizep && size != data->size)
 327                         die("object %s changed size!?", oid_to_hex(oid));
 328
 329                 batch_write(opt, contents, size);
 330                 free(contents);
 331         }
 332 }
 333
 334 static void batch_object_write(const char *obj_name, struct batch_options *opt,
 335                                struct expand_data *data)
 336 {
 337         struct strbuf buf = STRBUF_INIT;
 338
 339         if (!data->skip_object_info &&
 340             sha1_object_info_extended(data->oid.hash, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 341                 printf("%s missing\n",
 342                        obj_name ? obj_name : oid_to_hex(&data->oid));
 343                 fflush(stdout);
 344                 return;
 345         }
 346
 347         strbuf_expand(&buf, opt->format, expand_format, data);
 348         strbuf_addch(&buf, '\n');
 349         batch_write(opt, buf.buf, buf.len);
 350         strbuf_release(&buf);
 351
 352         if (opt->print_contents) {
 353                 print_object_or_die(opt, data);
 354                 batch_write(opt, "\n", 1);
 355         }
 356 }
 357
 358 static void batch_one_object(const char *obj_name, struct batch_options *opt,
 359                              struct expand_data *data)
 360 {
 361         struct object_context ctx;
 362         int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 363         enum follow_symlinks_result result;
 364
 365         result = get_sha1_with_context(obj_name, flags, data->oid.hash, &ctx);
 366         if (result != FOUND) {
 367                 switch (result) {
 368                 case MISSING_OBJECT:
 369                         printf("%s missing\n", obj_name);
 370                         break;
 371                 case DANGLING_SYMLINK:
 372                         printf("dangling %"PRIuMAX"\n%s\n",
 373                                (uintmax_t)strlen(obj_name), obj_name);
 374                         break;
 375                 case SYMLINK_LOOP:
 376                         printf("loop %"PRIuMAX"\n%s\n",
 377                                (uintmax_t)strlen(obj_name), obj_name);
 378                         break;
 379                 case NOT_DIR:
 380                         printf("notdir %"PRIuMAX"\n%s\n",
 381                                (uintmax_t)strlen(obj_name), obj_name);
 382                         break;
 383                 default:
 384                         die("BUG: unknown get_sha1_with_context result %d\n",
 385                                result);
 386                         break;
 387                 }
 388                 fflush(stdout);
 389                 return;
 390         }
 391
 392         if (ctx.mode == 0) {
 393                 printf("symlink %"PRIuMAX"\n%s\n",
 394                        (uintmax_t)ctx.symlink_path.len,
 395                        ctx.symlink_path.buf);
 396                 fflush(stdout);
 397                 return;
 398         }
 399
 400         batch_object_write(obj_name, opt, data);
 401 }
 402
 403 struct object_cb_data {
 404         struct batch_options *opt;
 405         struct expand_data *expand;
 406 };
 407
 408 static int batch_object_cb(const struct object_id *oid, void *vdata)
 409 {
 410         struct object_cb_data *data = vdata;
 411         oidcpy(&data->expand->oid, oid);
 412         batch_object_write(NULL, data->opt, data->expand);
 413         return 0;
 414 }
 415
 416 static int batch_loose_object(const struct object_id *oid,
 417                               const char *path,
 418                               void *data)
 419 {
 420         oid_array_append(data, oid);
 421         return 0;
 422 }
 423
 424 static int batch_packed_object(const struct object_id *oid,
 425                                struct packed_git *pack,
 426                                uint32_t pos,
 427                                void *data)
 428 {
 429         oid_array_append(data, oid);
 430         return 0;
 431 }
 432
 433 static int batch_objects(struct batch_options *opt)
 434 {
 435         struct strbuf buf = STRBUF_INIT;
 436         struct expand_data data;
 437         int save_warning;
 438         int retval = 0;
 439
 440         if (!opt->format)
 441                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
 442
 443         /*
 444          * Expand once with our special mark_query flag, which will prime the
 445          * object_info to be handed to sha1_object_info_extended for each
 446          * object.
 447          */
 448         memset(&data, 0, sizeof(data));
 449         data.mark_query = 1;
 450         strbuf_expand(&buf, opt->format, expand_format, &data);
 451         data.mark_query = 0;
 452         if (opt->cmdmode)
 453                 data.split_on_whitespace = 1;
 454
 455         if (opt->all_objects) {
 456                 struct object_info empty = OBJECT_INFO_INIT;
 457                 if (!memcmp(&data.info, &empty, sizeof(empty)))
 458                         data.skip_object_info = 1;
 459         }
 460
 461         /*
 462          * If we are printing out the object, then always fill in the type,
 463          * since we will want to decide whether or not to stream.
 464          */
 465         if (opt->print_contents)
 466                 data.info.typep = &data.type;
 467
 468         if (opt->all_objects) {
 469                 struct oid_array sa = OID_ARRAY_INIT;
 470                 struct object_cb_data cb;
 471
 472                 for_each_loose_object(batch_loose_object, &sa, 0);
 473                 for_each_packed_object(batch_packed_object, &sa, 0);
 474
 475                 cb.opt = opt;
 476                 cb.expand = &data;
 477                 oid_array_for_each_unique(&sa, batch_object_cb, &cb);
 478
 479                 oid_array_clear(&sa);
 480                 return 0;
 481         }
 482
 483         /*
 484          * We are going to call get_sha1 on a potentially very large number of
 485          * objects. In most large cases, these will be actual object sha1s. The
 486          * cost to double-check that each one is not also a ref (just so we can
 487          * warn) ends up dwarfing the actual cost of the object lookups
 488          * themselves. We can work around it by just turning off the warning.
 489          */
 490         save_warning = warn_on_object_refname_ambiguity;
 491         warn_on_object_refname_ambiguity = 0;
 492
 493         while (strbuf_getline(&buf, stdin) != EOF) {
 494                 if (data.split_on_whitespace) {
 495                         /*
 496                          * Split at first whitespace, tying off the beginning
 497                          * of the string and saving the remainder (or NULL) in
 498                          * data.rest.
 499                          */
 500                         char *p = strpbrk(buf.buf, " \t");
 501                         if (p) {
 502                                 while (*p && strchr(" \t", *p))
 503                                         *p++ = '\0';
 504                         }
 505                         data.rest = p;
 506                 }
 507
 508                 batch_one_object(buf.buf, opt, &data);
 509         }
 510
 511         strbuf_release(&buf);
 512         warn_on_object_refname_ambiguity = save_warning;
 513         return retval;
 514 }
 515
 516 static const char * const cat_file_usage[] = {
 517         N_("git cat-file (-t [--allow-unknown-type] | -s [--allow-unknown-type] | -e | -p | <type> | --textconv | --filters) [--path=<path>] <object>"),
 518         N_("git cat-file (--batch | --batch-check) [--follow-symlinks] [--textconv | --filters]"),
 519         NULL
 520 };
 521
 522 static int git_cat_file_config(const char *var, const char *value, void *cb)
 523 {
 524         if (userdiff_config(var, value) < 0)
 525                 return -1;
 526
 527         return git_default_config(var, value, cb);
 528 }
 529
 530 static int batch_option_callback(const struct option *opt,
 531                                  const char *arg,
 532                                  int unset)
 533 {
 534         struct batch_options *bo = opt->value;
 535
 536         if (bo->enabled) {
 537                 return 1;
 538         }
 539
 540         bo->enabled = 1;
 541         bo->print_contents = !strcmp(opt->long_name, "batch");
 542         bo->format = arg;
 543
 544         return 0;
 545 }
 546
 547 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 548 {
 549         int opt = 0;
 550         const char *exp_type = NULL, *obj_name = NULL;
 551         struct batch_options batch = {0};
 552         int unknown_type = 0;
 553
 554         const struct option options[] = {
 555                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 556                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 557                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 558                 OPT_CMDMODE('e', NULL, &opt,
 559                             N_("exit with zero when there's no error"), 'e'),
 560                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 561                 OPT_CMDMODE(0, "textconv", &opt,
 562                             N_("for blob objects, run textconv on object's content"), 'c'),
 563                 OPT_CMDMODE(0, "filters", &opt,
 564                             N_("for blob objects, run filters on object's content"), 'w'),
 565                 OPT_STRING(0, "path", &force_path, N_("blob"),
 566                            N_("use a specific path for --textconv/--filters")),
 567                 OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 568                           N_("allow -s and -t to work with broken/corrupt objects")),
 569                 OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
 570                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
 571                         N_("show info and content of objects fed from the standard input"),
 572                         PARSE_OPT_OPTARG, batch_option_callback },
 573                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 574                         N_("show info about objects fed from the standard input"),
 575                         PARSE_OPT_OPTARG, batch_option_callback },
 576                 OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 577                          N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 578                 OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
 579                          N_("show all objects with --batch or --batch-check")),
 580                 OPT_END()
 581         };
 582
 583         git_config(git_cat_file_config, NULL);
 584
 585         batch.buffer_output = -1;
 586         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
 587
 588         if (opt) {
 589                 if (batch.enabled && (opt == 'c' || opt == 'w'))
 590                         batch.cmdmode = opt;
 591                 else if (argc == 1)
 592                         obj_name = argv[0];
 593                 else
 594                         usage_with_options(cat_file_usage, options);
 595         }
 596         if (!opt && !batch.enabled) {
 597                 if (argc == 2) {
 598                         exp_type = argv[0];
 599                         obj_name = argv[1];
 600                 } else
 601                         usage_with_options(cat_file_usage, options);
 602         }
 603         if (batch.enabled) {
 604                 if (batch.cmdmode != opt || argc)
 605                         usage_with_options(cat_file_usage, options);
 606                 if (batch.cmdmode && batch.all_objects)
 607                         die("--batch-all-objects cannot be combined with "
 608                             "--textconv nor with --filters");
 609         }
 610
 611         if ((batch.follow_symlinks || batch.all_objects) && !batch.enabled) {
 612                 usage_with_options(cat_file_usage, options);
 613         }
 614
 615         if (force_path && opt != 'c' && opt != 'w') {
 616                 error("--path=<path> needs --textconv or --filters");
 617                 usage_with_options(cat_file_usage, options);
 618         }
 619
 620         if (force_path && batch.enabled) {
 621                 error("--path=<path> incompatible with --batch");
 622                 usage_with_options(cat_file_usage, options);
 623         }
 624
 625         if (batch.buffer_output < 0)
 626                 batch.buffer_output = batch.all_objects;
 627
 628         if (batch.enabled)
 629                 return batch_objects(&batch);
 630
 631         if (unknown_type && opt != 't' && opt != 's')
 632                 die("git cat-file --allow-unknown-type: use with -s or -t");
 633         return cat_one_file(opt, exp_type, obj_name, unknown_type);
 634 }