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