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
  12 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
  13                         int unknown_type)
  14 {
  15         unsigned char sha1[20];
  16         enum object_type type;
  17         char *buf;
  18         unsigned long size;
  19         struct object_context obj_context;
  20         struct object_info oi = {NULL};
  21         struct strbuf sb = STRBUF_INIT;
  22         unsigned flags = LOOKUP_REPLACE_OBJECT;
  23
  24         if (unknown_type)
  25                 flags |= LOOKUP_UNKNOWN_OBJECT;
  26
  27         if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
  28                 die("Not a valid object name %s", obj_name);
  29
  30         buf = NULL;
  31         switch (opt) {
  32         case 't':
  33                 oi.typename = &sb;
  34                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  35                         die("git cat-file: could not get object info");
  36                 if (sb.len) {
  37                         printf("%s\n", sb.buf);
  38                         strbuf_release(&sb);
  39                         return 0;
  40                 }
  41                 break;
  42
  43         case 's':
  44                 oi.sizep = &size;
  45                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  46                         die("git cat-file: could not get object info");
  47                 printf("%lu\n", size);
  48                 return 0;
  49
  50         case 'e':
  51                 return !has_sha1_file(sha1);
  52
  53         case 'c':
  54                 if (!obj_context.path[0])
  55                         die("git cat-file --textconv %s: <object> must be <sha1:path>",
  56                             obj_name);
  57
  58                 if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
  59                         break;
  60
  61         case 'p':
  62                 type = sha1_object_info(sha1, NULL);
  63                 if (type < 0)
  64                         die("Not a valid object name %s", obj_name);
  65
  66                 /* custom pretty-print here */
  67                 if (type == OBJ_TREE) {
  68                         const char *ls_args[3] = { NULL };
  69                         ls_args[0] =  "ls-tree";
  70                         ls_args[1] =  obj_name;
  71                         return cmd_ls_tree(2, ls_args, NULL);
  72                 }
  73
  74                 if (type == OBJ_BLOB)
  75                         return stream_blob_to_fd(1, sha1, NULL, 0);
  76                 buf = read_sha1_file(sha1, &type, &size);
  77                 if (!buf)
  78                         die("Cannot read object %s", obj_name);
  79
  80                 /* otherwise just spit out the data */
  81                 break;
  82
  83         case 0:
  84                 if (type_from_string(exp_type) == OBJ_BLOB) {
  85                         unsigned char blob_sha1[20];
  86                         if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
  87                                 char *buffer = read_sha1_file(sha1, &type, &size);
  88                                 const char *target;
  89                                 if (!skip_prefix(buffer, "object ", &target) ||
  90                                     get_sha1_hex(target, blob_sha1))
  91                                         die("%s not a valid tag", sha1_to_hex(sha1));
  92                                 free(buffer);
  93                         } else
  94                                 hashcpy(blob_sha1, sha1);
  95
  96                         if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
  97                                 return stream_blob_to_fd(1, blob_sha1, NULL, 0);
  98                         /*
  99                          * we attempted to dereference a tag to a blob
 100                          * and failed; there may be new dereference
 101                          * mechanisms this code is not aware of.
 102                          * fall-back to the usual case.
 103                          */
 104                 }
 105                 buf = read_object_with_reference(sha1, exp_type, &size, NULL);
 106                 break;
 107
 108         default:
 109                 die("git cat-file: unknown option: %s", exp_type);
 110         }
 111
 112         if (!buf)
 113                 die("git cat-file %s: bad file", obj_name);
 114
 115         write_or_die(1, buf, size);
 116         return 0;
 117 }
 118
 119 struct expand_data {
 120         unsigned char sha1[20];
 121         enum object_type type;
 122         unsigned long size;
 123         unsigned long disk_size;
 124         const char *rest;
 125         unsigned char delta_base_sha1[20];
 126
 127         /*
 128          * If mark_query is true, we do not expand anything, but rather
 129          * just mark the object_info with items we wish to query.
 130          */
 131         int mark_query;
 132
 133         /*
 134          * Whether to split the input on whitespace before feeding it to
 135          * get_sha1; this is decided during the mark_query phase based on
 136          * whether we have a %(rest) token in our format.
 137          */
 138         int split_on_whitespace;
 139
 140         /*
 141          * After a mark_query run, this object_info is set up to be
 142          * passed to sha1_object_info_extended. It will point to the data
 143          * elements above, so you can retrieve the response from there.
 144          */
 145         struct object_info info;
 146 };
 147
 148 static int is_atom(const char *atom, const char *s, int slen)
 149 {
 150         int alen = strlen(atom);
 151         return alen == slen && !memcmp(atom, s, alen);
 152 }
 153
 154 static void expand_atom(struct strbuf *sb, const char *atom, int len,
 155                         void *vdata)
 156 {
 157         struct expand_data *data = vdata;
 158
 159         if (is_atom("objectname", atom, len)) {
 160                 if (!data->mark_query)
 161                         strbuf_addstr(sb, sha1_to_hex(data->sha1));
 162         } else if (is_atom("objecttype", atom, len)) {
 163                 if (data->mark_query)
 164                         data->info.typep = &data->type;
 165                 else
 166                         strbuf_addstr(sb, typename(data->type));
 167         } else if (is_atom("objectsize", atom, len)) {
 168                 if (data->mark_query)
 169                         data->info.sizep = &data->size;
 170                 else
 171                         strbuf_addf(sb, "%lu", data->size);
 172         } else if (is_atom("objectsize:disk", atom, len)) {
 173                 if (data->mark_query)
 174                         data->info.disk_sizep = &data->disk_size;
 175                 else
 176                         strbuf_addf(sb, "%lu", data->disk_size);
 177         } else if (is_atom("rest", atom, len)) {
 178                 if (data->mark_query)
 179                         data->split_on_whitespace = 1;
 180                 else if (data->rest)
 181                         strbuf_addstr(sb, data->rest);
 182         } else if (is_atom("deltabase", atom, len)) {
 183                 if (data->mark_query)
 184                         data->info.delta_base_sha1 = data->delta_base_sha1;
 185                 else
 186                         strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
 187         } else
 188                 die("unknown format element: %.*s", len, atom);
 189 }
 190
 191 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 192 {
 193         const char *end;
 194
 195         if (*start != '(')
 196                 return 0;
 197         end = strchr(start + 1, ')');
 198         if (!end)
 199                 die("format element '%s' does not end in ')'", start);
 200
 201         expand_atom(sb, start + 1, end - start - 1, data);
 202
 203         return end - start + 1;
 204 }
 205
 206 static void print_object_or_die(int fd, struct expand_data *data)
 207 {
 208         const unsigned char *sha1 = data->sha1;
 209
 210         assert(data->info.typep);
 211
 212         if (data->type == OBJ_BLOB) {
 213                 if (stream_blob_to_fd(fd, sha1, NULL, 0) < 0)
 214                         die("unable to stream %s to stdout", sha1_to_hex(sha1));
 215         }
 216         else {
 217                 enum object_type type;
 218                 unsigned long size;
 219                 void *contents;
 220
 221                 contents = read_sha1_file(sha1, &type, &size);
 222                 if (!contents)
 223                         die("object %s disappeared", sha1_to_hex(sha1));
 224                 if (type != data->type)
 225                         die("object %s changed type!?", sha1_to_hex(sha1));
 226                 if (data->info.sizep && size != data->size)
 227                         die("object %s changed size!?", sha1_to_hex(sha1));
 228
 229                 write_or_die(fd, contents, size);
 230                 free(contents);
 231         }
 232 }
 233
 234 struct batch_options {
 235         int enabled;
 236         int print_contents;
 237         const char *format;
 238 };
 239
 240 static int batch_one_object(const char *obj_name, struct batch_options *opt,
 241                             struct expand_data *data)
 242 {
 243         struct strbuf buf = STRBUF_INIT;
 244
 245         if (!obj_name)
 246            return 1;
 247
 248         if (get_sha1(obj_name, data->sha1)) {
 249                 printf("%s missing\n", obj_name);
 250                 fflush(stdout);
 251                 return 0;
 252         }
 253
 254         if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 255                 printf("%s missing\n", obj_name);
 256                 fflush(stdout);
 257                 return 0;
 258         }
 259
 260         strbuf_expand(&buf, opt->format, expand_format, data);
 261         strbuf_addch(&buf, '\n');
 262         write_or_die(1, buf.buf, buf.len);
 263         strbuf_release(&buf);
 264
 265         if (opt->print_contents) {
 266                 print_object_or_die(1, data);
 267                 write_or_die(1, "\n", 1);
 268         }
 269         return 0;
 270 }
 271
 272 static int batch_objects(struct batch_options *opt)
 273 {
 274         struct strbuf buf = STRBUF_INIT;
 275         struct expand_data data;
 276         int save_warning;
 277         int retval = 0;
 278
 279         if (!opt->format)
 280                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
 281
 282         /*
 283          * Expand once with our special mark_query flag, which will prime the
 284          * object_info to be handed to sha1_object_info_extended for each
 285          * object.
 286          */
 287         memset(&data, 0, sizeof(data));
 288         data.mark_query = 1;
 289         strbuf_expand(&buf, opt->format, expand_format, &data);
 290         data.mark_query = 0;
 291
 292         /*
 293          * If we are printing out the object, then always fill in the type,
 294          * since we will want to decide whether or not to stream.
 295          */
 296         if (opt->print_contents)
 297                 data.info.typep = &data.type;
 298
 299         /*
 300          * We are going to call get_sha1 on a potentially very large number of
 301          * objects. In most large cases, these will be actual object sha1s. The
 302          * cost to double-check that each one is not also a ref (just so we can
 303          * warn) ends up dwarfing the actual cost of the object lookups
 304          * themselves. We can work around it by just turning off the warning.
 305          */
 306         save_warning = warn_on_object_refname_ambiguity;
 307         warn_on_object_refname_ambiguity = 0;
 308
 309         while (strbuf_getline(&buf, stdin, '\n') != EOF) {
 310                 if (data.split_on_whitespace) {
 311                         /*
 312                          * Split at first whitespace, tying off the beginning
 313                          * of the string and saving the remainder (or NULL) in
 314                          * data.rest.
 315                          */
 316                         char *p = strpbrk(buf.buf, " \t");
 317                         if (p) {
 318                                 while (*p && strchr(" \t", *p))
 319                                         *p++ = '\0';
 320                         }
 321                         data.rest = p;
 322                 }
 323
 324                 retval = batch_one_object(buf.buf, opt, &data);
 325                 if (retval)
 326                         break;
 327         }
 328
 329         strbuf_release(&buf);
 330         warn_on_object_refname_ambiguity = save_warning;
 331         return retval;
 332 }
 333
 334 static const char * const cat_file_usage[] = {
 335         N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
 336         N_("git cat-file (--batch | --batch-check) < <list-of-objects>"),
 337         NULL
 338 };
 339
 340 static int git_cat_file_config(const char *var, const char *value, void *cb)
 341 {
 342         if (userdiff_config(var, value) < 0)
 343                 return -1;
 344
 345         return git_default_config(var, value, cb);
 346 }
 347
 348 static int batch_option_callback(const struct option *opt,
 349                                  const char *arg,
 350                                  int unset)
 351 {
 352         struct batch_options *bo = opt->value;
 353
 354         if (unset) {
 355                 memset(bo, 0, sizeof(*bo));
 356                 return 0;
 357         }
 358
 359         bo->enabled = 1;
 360         bo->print_contents = !strcmp(opt->long_name, "batch");
 361         bo->format = arg;
 362
 363         return 0;
 364 }
 365
 366 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 367 {
 368         int opt = 0;
 369         const char *exp_type = NULL, *obj_name = NULL;
 370         struct batch_options batch = {0};
 371         int unknown_type = 0;
 372
 373         const struct option options[] = {
 374                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 375                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 376                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 377                 OPT_CMDMODE('e', NULL, &opt,
 378                             N_("exit with zero when there's no error"), 'e'),
 379                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 380                 OPT_CMDMODE(0, "textconv", &opt,
 381                             N_("for blob objects, run textconv on object's content"), 'c'),
 382                 OPT_BOOL( 0, "allow-unknown-type", &unknown_type,
 383                           N_("allow -s and -t to work with broken/corrupt objects")),
 384                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
 385                         N_("show info and content of objects fed from the standard input"),
 386                         PARSE_OPT_OPTARG, batch_option_callback },
 387                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 388                         N_("show info about objects fed from the standard input"),
 389                         PARSE_OPT_OPTARG, batch_option_callback },
 390                 OPT_END()
 391         };
 392
 393         git_config(git_cat_file_config, NULL);
 394
 395         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
 396
 397         if (opt) {
 398                 if (argc == 1)
 399                         obj_name = argv[0];
 400                 else
 401                         usage_with_options(cat_file_usage, options);
 402         }
 403         if (!opt && !batch.enabled) {
 404                 if (argc == 2) {
 405                         exp_type = argv[0];
 406                         obj_name = argv[1];
 407                 } else
 408                         usage_with_options(cat_file_usage, options);
 409         }
 410         if (batch.enabled && (opt || argc)) {
 411                 usage_with_options(cat_file_usage, options);
 412         }
 413
 414         if (batch.enabled)
 415                 return batch_objects(&batch);
 416
 417         if (unknown_type && opt != 't' && opt != 's')
 418                 die("git cat-file --allow-unknown-type: use with -s or -t");
 419         return cat_one_file(opt, exp_type, obj_name, unknown_type);
 420 }