builtin/cat-file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7 #include "builtin.h"
   8 #include "parse-options.h"
   9 #include "userdiff.h"
  10 #include "streaming.h"
  11 #include "tree-walk.h"
  12 #include "sha1-array.h"
  13
  14 struct batch_options {
  15         int enabled;
  16         int follow_symlinks;
  17         int print_contents;
  18         int buffer_output;
  19         int all_objects;
  20         const char *format;
  21 };
  22
  23 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
  24                         int unknown_type)
  25 {
  26         unsigned char sha1[20];
  27         enum object_type type;
  28         char *buf;
  29         unsigned long size;
  30         struct object_context obj_context;
  31         struct object_info oi = {NULL};
  32         struct strbuf sb = STRBUF_INIT;
  33         unsigned flags = LOOKUP_REPLACE_OBJECT;
  34
  35         if (unknown_type)
  36                 flags |= LOOKUP_UNKNOWN_OBJECT;
  37
  38         if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
  39                 die("Not a valid object name %s", obj_name);
  40
  41         buf = NULL;
  42         switch (opt) {
  43         case 't':
  44                 oi.typename = &sb;
  45                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  46                         die("git cat-file: could not get object info");
  47                 if (sb.len) {
  48                         printf("%s\n", sb.buf);
  49                         strbuf_release(&sb);
  50                         return 0;
  51                 }
  52                 break;
  53
  54         case 's':
  55                 oi.sizep = &size;
  56                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  57                         die("git cat-file: could not get object info");
  58                 printf("%lu\n", size);
  59                 return 0;
  60
  61         case 'e':
  62                 return !has_sha1_file(sha1);
  63
  64         case 'c':
  65                 if (!obj_context.path[0])
  66                         die("git cat-file --textconv %s: <object> must be <sha1:path>",
  67                             obj_name);
  68
  69                 if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
  70                         break;
  71
  72         case 'p':
  73                 type = sha1_object_info(sha1, NULL);
  74                 if (type < 0)
  75                         die("Not a valid object name %s", obj_name);
  76
  77                 /* custom pretty-print here */
  78                 if (type == OBJ_TREE) {
  79                         const char *ls_args[3] = { NULL };
  80                         ls_args[0] =  "ls-tree";
  81                         ls_args[1] =  obj_name;
  82                         return cmd_ls_tree(2, ls_args, NULL);
  83                 }
  84
  85                 if (type == OBJ_BLOB)
  86                         return stream_blob_to_fd(1, sha1, NULL, 0);
  87                 buf = read_sha1_file(sha1, &type, &size);
  88                 if (!buf)
  89                         die("Cannot read object %s", obj_name);
  90
  91                 /* otherwise just spit out the data */
  92                 break;
  93
  94         case 0:
  95                 if (type_from_string(exp_type) == OBJ_BLOB) {
  96                         unsigned char blob_sha1[20];
  97                         if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
  98                                 char *buffer = read_sha1_file(sha1, &type, &size);
  99                                 const char *target;
 100                                 if (!skip_prefix(buffer, "object ", &target) ||
 101                                     get_sha1_hex(target, blob_sha1))
 102                                         die("%s not a valid tag", sha1_to_hex(sha1));
 103                                 free(buffer);
 104                         } else
 105                                 hashcpy(blob_sha1, sha1);
 106
 107                         if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
 108                                 return stream_blob_to_fd(1, blob_sha1, NULL, 0);
 109                         /*
 110                          * we attempted to dereference a tag to a blob
 111                          * and failed; there may be new dereference
 112                          * mechanisms this code is not aware of.
 113                          * fall-back to the usual case.
 114                          */
 115                 }
 116                 buf = read_object_with_reference(sha1, exp_type, &size, NULL);
 117                 break;
 118
 119         default:
 120                 die("git cat-file: unknown option: %s", exp_type);
 121         }
 122
 123         if (!buf)
 124                 die("git cat-file %s: bad file", obj_name);
 125
 126         write_or_die(1, buf, size);
 127         return 0;
 128 }
 129
 130 struct expand_data {
 131         unsigned char sha1[20];
 132         enum object_type type;
 133         unsigned long size;
 134         off_t disk_size;
 135         const char *rest;
 136         unsigned char delta_base_sha1[20];
 137
 138         /*
 139          * If mark_query is true, we do not expand anything, but rather
 140          * just mark the object_info with items we wish to query.
 141          */
 142         int mark_query;
 143
 144         /*
 145          * Whether to split the input on whitespace before feeding it to
 146          * get_sha1; this is decided during the mark_query phase based on
 147          * whether we have a %(rest) token in our format.
 148          */
 149         int split_on_whitespace;
 150
 151         /*
 152          * After a mark_query run, this object_info is set up to be
 153          * passed to sha1_object_info_extended. It will point to the data
 154          * elements above, so you can retrieve the response from there.
 155          */
 156         struct object_info info;
 157
 158         /*
 159          * 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, sha1_to_hex(data->sha1));
 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_sha1;
 203                 else
 204                         strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
 205         } else
 206                 die("unknown format element: %.*s", len, atom);
 207 }
 208
 209 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 210 {
 211         const char *end;
 212
 213         if (*start != '(')
 214                 return 0;
 215         end = strchr(start + 1, ')');
 216         if (!end)
 217                 die("format element '%s' does not end in ')'", start);
 218
 219         expand_atom(sb, start + 1, end - start - 1, data);
 220
 221         return end - start + 1;
 222 }
 223
 224 static void batch_write(struct batch_options *opt, const void *data, int len)
 225 {
 226         if (opt->buffer_output) {
 227                 if (fwrite(data, 1, len, stdout) != len)
 228                         die_errno("unable to write to stdout");
 229         } else
 230                 write_or_die(1, data, len);
 231 }
 232
 233 static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
 234 {
 235         const unsigned char *sha1 = data->sha1;
 236
 237         assert(data->info.typep);
 238
 239         if (data->type == OBJ_BLOB) {
 240                 if (opt->buffer_output)
 241                         fflush(stdout);
 242                 if (stream_blob_to_fd(1, sha1, NULL, 0) < 0)
 243                         die("unable to stream %s to stdout", sha1_to_hex(sha1));
 244         }
 245         else {
 246                 enum object_type type;
 247                 unsigned long size;
 248                 void *contents;
 249
 250                 contents = read_sha1_file(sha1, &type, &size);
 251                 if (!contents)
 252                         die("object %s disappeared", sha1_to_hex(sha1));
 253                 if (type != data->type)
 254                         die("object %s changed type!?", sha1_to_hex(sha1));
 255                 if (data->info.sizep && size != data->size)
 256                         die("object %s changed size!?", sha1_to_hex(sha1));
 257
 258                 batch_write(opt, contents, size);
 259                 free(contents);
 260         }
 261 }
 262
 263 static void batch_object_write(const char *obj_name, struct batch_options *opt,
 264                                struct expand_data *data)
 265 {
 266         struct strbuf buf = STRBUF_INIT;
 267
 268         if (!data->skip_object_info &&
 269             sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 270                 printf("%s missing\n", obj_name ? obj_name : sha1_to_hex(data->sha1));
 271                 fflush(stdout);
 272                 return;
 273         }
 274
 275         strbuf_expand(&buf, opt->format, expand_format, data);
 276         strbuf_addch(&buf, '\n');
 277         batch_write(opt, buf.buf, buf.len);
 278         strbuf_release(&buf);
 279
 280         if (opt->print_contents) {
 281                 print_object_or_die(opt, data);
 282                 batch_write(opt, "\n", 1);
 283         }
 284 }
 285
 286 static void batch_one_object(const char *obj_name, struct batch_options *opt,
 287                              struct expand_data *data)
 288 {
 289         struct object_context ctx;
 290         int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 291         enum follow_symlinks_result result;
 292
 293         result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
 294         if (result != FOUND) {
 295                 switch (result) {
 296                 case MISSING_OBJECT:
 297                         printf("%s missing\n", obj_name);
 298                         break;
 299                 case DANGLING_SYMLINK:
 300                         printf("dangling %"PRIuMAX"\n%s\n",
 301                                (uintmax_t)strlen(obj_name), obj_name);
 302                         break;
 303                 case SYMLINK_LOOP:
 304                         printf("loop %"PRIuMAX"\n%s\n",
 305                                (uintmax_t)strlen(obj_name), obj_name);
 306                         break;
 307                 case NOT_DIR:
 308                         printf("notdir %"PRIuMAX"\n%s\n",
 309                                (uintmax_t)strlen(obj_name), obj_name);
 310                         break;
 311                 default:
 312                         die("BUG: unknown get_sha1_with_context result %d\n",
 313                                result);
 314                         break;
 315                 }
 316                 fflush(stdout);
 317                 return;
 318         }
 319
 320         if (ctx.mode == 0) {
 321                 printf("symlink %"PRIuMAX"\n%s\n",
 322                        (uintmax_t)ctx.symlink_path.len,
 323                        ctx.symlink_path.buf);
 324                 fflush(stdout);
 325                 return;
 326         }
 327
 328         batch_object_write(obj_name, opt, data);
 329 }
 330
 331 struct object_cb_data {
 332         struct batch_options *opt;
 333         struct expand_data *expand;
 334 };
 335
 336 static void batch_object_cb(const unsigned char sha1[20], void *vdata)
 337 {
 338         struct object_cb_data *data = vdata;
 339         hashcpy(data->expand->sha1, sha1);
 340         batch_object_write(NULL, data->opt, data->expand);
 341 }
 342
 343 static int batch_loose_object(const unsigned char *sha1,
 344                               const char *path,
 345                               void *data)
 346 {
 347         sha1_array_append(data, sha1);
 348         return 0;
 349 }
 350
 351 static int batch_packed_object(const unsigned char *sha1,
 352                                struct packed_git *pack,
 353                                uint32_t pos,
 354                                void *data)
 355 {
 356         sha1_array_append(data, sha1);
 357         return 0;
 358 }
 359
 360 static int batch_objects(struct batch_options *opt)
 361 {
 362         struct strbuf buf = STRBUF_INIT;
 363         struct expand_data data;
 364         int save_warning;
 365         int retval = 0;
 366
 367         if (!opt->format)
 368                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
 369
 370         /*
 371          * Expand once with our special mark_query flag, which will prime the
 372          * object_info to be handed to sha1_object_info_extended for each
 373          * object.
 374          */
 375         memset(&data, 0, sizeof(data));
 376         data.mark_query = 1;
 377         strbuf_expand(&buf, opt->format, expand_format, &data);
 378         data.mark_query = 0;
 379
 380         if (opt->all_objects) {
 381                 struct object_info empty;
 382                 memset(&empty, 0, sizeof(empty));
 383                 if (!memcmp(&data.info, &empty, sizeof(empty)))
 384                         data.skip_object_info = 1;
 385         }
 386
 387         /*
 388          * If we are printing out the object, then always fill in the type,
 389          * since we will want to decide whether or not to stream.
 390          */
 391         if (opt->print_contents)
 392                 data.info.typep = &data.type;
 393
 394         if (opt->all_objects) {
 395                 struct sha1_array sa = SHA1_ARRAY_INIT;
 396                 struct object_cb_data cb;
 397
 398                 for_each_loose_object(batch_loose_object, &sa, 0);
 399                 for_each_packed_object(batch_packed_object, &sa, 0);
 400
 401                 cb.opt = opt;
 402                 cb.expand = &data;
 403                 sha1_array_for_each_unique(&sa, batch_object_cb, &cb);
 404
 405                 sha1_array_clear(&sa);
 406                 return 0;
 407         }
 408
 409         /*
 410          * We are going to call get_sha1 on a potentially very large number of
 411          * objects. In most large cases, these will be actual object sha1s. The
 412          * cost to double-check that each one is not also a ref (just so we can
 413          * warn) ends up dwarfing the actual cost of the object lookups
 414          * themselves. We can work around it by just turning off the warning.
 415          */
 416         save_warning = warn_on_object_refname_ambiguity;
 417         warn_on_object_refname_ambiguity = 0;
 418
 419         while (strbuf_getline(&buf, stdin) != EOF) {
 420                 if (data.split_on_whitespace) {
 421                         /*
 422                          * Split at first whitespace, tying off the beginning
 423                          * of the string and saving the remainder (or NULL) in
 424                          * data.rest.
 425                          */
 426                         char *p = strpbrk(buf.buf, " \t");
 427                         if (p) {
 428                                 while (*p && strchr(" \t", *p))
 429                                         *p++ = '\0';
 430                         }
 431                         data.rest = p;
 432                 }
 433
 434                 batch_one_object(buf.buf, opt, &data);
 435         }
 436
 437         strbuf_release(&buf);
 438         warn_on_object_refname_ambiguity = save_warning;
 439         return retval;
 440 }
 441
 442 static const char * const cat_file_usage[] = {
 443         N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
 444         N_("git cat-file (--batch | --batch-check) [--follow-symlinks]"),
 445         NULL
 446 };
 447
 448 static int git_cat_file_config(const char *var, const char *value, void *cb)
 449 {
 450         if (userdiff_config(var, value) < 0)
 451                 return -1;
 452
 453         return git_default_config(var, value, cb);
 454 }
 455
 456 static int batch_option_callback(const struct option *opt,
 457                                  const char *arg,
 458                                  int unset)
 459 {
 460         struct batch_options *bo = opt->value;
 461
 462         if (bo->enabled) {
 463                 return 1;
 464         }
 465
 466         bo->enabled = 1;
 467         bo->print_contents = !strcmp(opt->long_name, "batch");
 468         bo->format = arg;
 469
 470         return 0;
 471 }
 472
 473 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 474 {
 475         int opt = 0;
 476         const char *exp_type = NULL, *obj_name = NULL;
 477         struct batch_options batch = {0};
 478         int unknown_type = 0;
 479
 480         const struct option options[] = {
 481                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 482                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 483                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 484                 OPT_CMDMODE('e', NULL, &opt,
 485                             N_("exit with zero when there's no error"), 'e'),
 486                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 487                 OPT_CMDMODE(0, "textconv", &opt,
 488                             N_("for blob objects, run textconv on object's content"), 'c'),
 489                 OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 490                           N_("allow -s and -t to work with broken/corrupt objects")),
 491                 OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
 492                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
 493                         N_("show info and content of objects fed from the standard input"),
 494                         PARSE_OPT_OPTARG, batch_option_callback },
 495                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 496                         N_("show info about objects fed from the standard input"),
 497                         PARSE_OPT_OPTARG, batch_option_callback },
 498                 OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 499                          N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 500                 OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
 501                          N_("show all objects with --batch or --batch-check")),
 502                 OPT_END()
 503         };
 504
 505         git_config(git_cat_file_config, NULL);
 506
 507         batch.buffer_output = -1;
 508         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
 509
 510         if (opt) {
 511                 if (argc == 1)
 512                         obj_name = argv[0];
 513                 else
 514                         usage_with_options(cat_file_usage, options);
 515         }
 516         if (!opt && !batch.enabled) {
 517                 if (argc == 2) {
 518                         exp_type = argv[0];
 519                         obj_name = argv[1];
 520                 } else
 521                         usage_with_options(cat_file_usage, options);
 522         }
 523         if (batch.enabled && (opt || argc)) {
 524                 usage_with_options(cat_file_usage, options);
 525         }
 526
 527         if ((batch.follow_symlinks || batch.all_objects) && !batch.enabled) {
 528                 usage_with_options(cat_file_usage, options);
 529         }
 530
 531         if (batch.buffer_output < 0)
 532                 batch.buffer_output = batch.all_objects;
 533
 534         if (batch.enabled)
 535                 return batch_objects(&batch);
 536
 537         if (unknown_type && opt != 't' && opt != 's')
 538                 die("git cat-file --allow-unknown-type: use with -s or -t");
 539         return cat_one_file(opt, exp_type, obj_name, unknown_type);
 540 }