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