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