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