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