Andrew's git / gitweb.git / builtin/cat-file.c
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builtin / cat-file.con commit cat-file: add --buffer option (fc4937c)
   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
  13struct batch_options {
  14        int enabled;
  15        int follow_symlinks;
  16        int print_contents;
  17        int buffer_output;
  18        const char *format;
  19};
  20
  21static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
  22                        int unknown_type)
  23{
  24        unsigned char sha1[20];
  25        enum object_type type;
  26        char *buf;
  27        unsigned long size;
  28        struct object_context obj_context;
  29        struct object_info oi = {NULL};
  30        struct strbuf sb = STRBUF_INIT;
  31        unsigned flags = LOOKUP_REPLACE_OBJECT;
  32
  33        if (unknown_type)
  34                flags |= LOOKUP_UNKNOWN_OBJECT;
  35
  36        if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
  37                die("Not a valid object name %s", obj_name);
  38
  39        buf = NULL;
  40        switch (opt) {
  41        case 't':
  42                oi.typename = &sb;
  43                if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  44                        die("git cat-file: could not get object info");
  45                if (sb.len) {
  46                        printf("%s\n", sb.buf);
  47                        strbuf_release(&sb);
  48                        return 0;
  49                }
  50                break;
  51
  52        case 's':
  53                oi.sizep = &size;
  54                if (sha1_object_info_extended(sha1, &oi, flags) < 0)
  55                        die("git cat-file: could not get object info");
  56                printf("%lu\n", size);
  57                return 0;
  58
  59        case 'e':
  60                return !has_sha1_file(sha1);
  61
  62        case 'c':
  63                if (!obj_context.path[0])
  64                        die("git cat-file --textconv %s: <object> must be <sha1:path>",
  65                            obj_name);
  66
  67                if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
  68                        break;
  69
  70        case 'p':
  71                type = sha1_object_info(sha1, NULL);
  72                if (type < 0)
  73                        die("Not a valid object name %s", obj_name);
  74
  75                /* custom pretty-print here */
  76                if (type == OBJ_TREE) {
  77                        const char *ls_args[3] = { NULL };
  78                        ls_args[0] =  "ls-tree";
  79                        ls_args[1] =  obj_name;
  80                        return cmd_ls_tree(2, ls_args, NULL);
  81                }
  82
  83                if (type == OBJ_BLOB)
  84                        return stream_blob_to_fd(1, sha1, NULL, 0);
  85                buf = read_sha1_file(sha1, &type, &size);
  86                if (!buf)
  87                        die("Cannot read object %s", obj_name);
  88
  89                /* otherwise just spit out the data */
  90                break;
  91
  92        case 0:
  93                if (type_from_string(exp_type) == OBJ_BLOB) {
  94                        unsigned char blob_sha1[20];
  95                        if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
  96                                char *buffer = read_sha1_file(sha1, &type, &size);
  97                                const char *target;
  98                                if (!skip_prefix(buffer, "object ", &target) ||
  99                                    get_sha1_hex(target, blob_sha1))
 100                                        die("%s not a valid tag", sha1_to_hex(sha1));
 101                                free(buffer);
 102                        } else
 103                                hashcpy(blob_sha1, sha1);
 104
 105                        if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
 106                                return stream_blob_to_fd(1, blob_sha1, NULL, 0);
 107                        /*
 108                         * we attempted to dereference a tag to a blob
 109                         * and failed; there may be new dereference
 110                         * mechanisms this code is not aware of.
 111                         * fall-back to the usual case.
 112                         */
 113                }
 114                buf = read_object_with_reference(sha1, exp_type, &size, NULL);
 115                break;
 116
 117        default:
 118                die("git cat-file: unknown option: %s", exp_type);
 119        }
 120
 121        if (!buf)
 122                die("git cat-file %s: bad file", obj_name);
 123
 124        write_or_die(1, buf, size);
 125        return 0;
 126}
 127
 128struct expand_data {
 129        unsigned char sha1[20];
 130        enum object_type type;
 131        unsigned long size;
 132        unsigned long disk_size;
 133        const char *rest;
 134        unsigned char delta_base_sha1[20];
 135
 136        /*
 137         * If mark_query is true, we do not expand anything, but rather
 138         * just mark the object_info with items we wish to query.
 139         */
 140        int mark_query;
 141
 142        /*
 143         * Whether to split the input on whitespace before feeding it to
 144         * get_sha1; this is decided during the mark_query phase based on
 145         * whether we have a %(rest) token in our format.
 146         */
 147        int split_on_whitespace;
 148
 149        /*
 150         * After a mark_query run, this object_info is set up to be
 151         * passed to sha1_object_info_extended. It will point to the data
 152         * elements above, so you can retrieve the response from there.
 153         */
 154        struct object_info info;
 155};
 156
 157static int is_atom(const char *atom, const char *s, int slen)
 158{
 159        int alen = strlen(atom);
 160        return alen == slen && !memcmp(atom, s, alen);
 161}
 162
 163static void expand_atom(struct strbuf *sb, const char *atom, int len,
 164                        void *vdata)
 165{
 166        struct expand_data *data = vdata;
 167
 168        if (is_atom("objectname", atom, len)) {
 169                if (!data->mark_query)
 170                        strbuf_addstr(sb, sha1_to_hex(data->sha1));
 171        } else if (is_atom("objecttype", atom, len)) {
 172                if (data->mark_query)
 173                        data->info.typep = &data->type;
 174                else
 175                        strbuf_addstr(sb, typename(data->type));
 176        } else if (is_atom("objectsize", atom, len)) {
 177                if (data->mark_query)
 178                        data->info.sizep = &data->size;
 179                else
 180                        strbuf_addf(sb, "%lu", data->size);
 181        } else if (is_atom("objectsize:disk", atom, len)) {
 182                if (data->mark_query)
 183                        data->info.disk_sizep = &data->disk_size;
 184                else
 185                        strbuf_addf(sb, "%lu", data->disk_size);
 186        } else if (is_atom("rest", atom, len)) {
 187                if (data->mark_query)
 188                        data->split_on_whitespace = 1;
 189                else if (data->rest)
 190                        strbuf_addstr(sb, data->rest);
 191        } else if (is_atom("deltabase", atom, len)) {
 192                if (data->mark_query)
 193                        data->info.delta_base_sha1 = data->delta_base_sha1;
 194                else
 195                        strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
 196        } else
 197                die("unknown format element: %.*s", len, atom);
 198}
 199
 200static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 201{
 202        const char *end;
 203
 204        if (*start != '(')
 205                return 0;
 206        end = strchr(start + 1, ')');
 207        if (!end)
 208                die("format element '%s' does not end in ')'", start);
 209
 210        expand_atom(sb, start + 1, end - start - 1, data);
 211
 212        return end - start + 1;
 213}
 214
 215static void batch_write(struct batch_options *opt, const void *data, int len)
 216{
 217        if (opt->buffer_output) {
 218                if (fwrite(data, 1, len, stdout) != len)
 219                        die_errno("unable to write to stdout");
 220        } else
 221                write_or_die(1, data, len);
 222}
 223
 224static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
 225{
 226        const unsigned char *sha1 = data->sha1;
 227
 228        assert(data->info.typep);
 229
 230        if (data->type == OBJ_BLOB) {
 231                if (opt->buffer_output)
 232                        fflush(stdout);
 233                if (stream_blob_to_fd(1, sha1, NULL, 0) < 0)
 234                        die("unable to stream %s to stdout", sha1_to_hex(sha1));
 235        }
 236        else {
 237                enum object_type type;
 238                unsigned long size;
 239                void *contents;
 240
 241                contents = read_sha1_file(sha1, &type, &size);
 242                if (!contents)
 243                        die("object %s disappeared", sha1_to_hex(sha1));
 244                if (type != data->type)
 245                        die("object %s changed type!?", sha1_to_hex(sha1));
 246                if (data->info.sizep && size != data->size)
 247                        die("object %s changed size!?", sha1_to_hex(sha1));
 248
 249                batch_write(opt, contents, size);
 250                free(contents);
 251        }
 252}
 253
 254static int batch_one_object(const char *obj_name, struct batch_options *opt,
 255                            struct expand_data *data)
 256{
 257        struct strbuf buf = STRBUF_INIT;
 258        struct object_context ctx;
 259        int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 260        enum follow_symlinks_result result;
 261
 262        if (!obj_name)
 263           return 1;
 264
 265        result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
 266        if (result != FOUND) {
 267                switch (result) {
 268                case MISSING_OBJECT:
 269                        printf("%s missing\n", obj_name);
 270                        break;
 271                case DANGLING_SYMLINK:
 272                        printf("dangling %"PRIuMAX"\n%s\n",
 273                               (uintmax_t)strlen(obj_name), obj_name);
 274                        break;
 275                case SYMLINK_LOOP:
 276                        printf("loop %"PRIuMAX"\n%s\n",
 277                               (uintmax_t)strlen(obj_name), obj_name);
 278                        break;
 279                case NOT_DIR:
 280                        printf("notdir %"PRIuMAX"\n%s\n",
 281                               (uintmax_t)strlen(obj_name), obj_name);
 282                        break;
 283                default:
 284                        die("BUG: unknown get_sha1_with_context result %d\n",
 285                               result);
 286                        break;
 287                }
 288                fflush(stdout);
 289                return 0;
 290        }
 291
 292        if (ctx.mode == 0) {
 293                printf("symlink %"PRIuMAX"\n%s\n",
 294                       (uintmax_t)ctx.symlink_path.len,
 295                       ctx.symlink_path.buf);
 296                fflush(stdout);
 297                return 0;
 298        }
 299
 300        if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 301                printf("%s missing\n", obj_name);
 302                fflush(stdout);
 303                return 0;
 304        }
 305
 306        strbuf_expand(&buf, opt->format, expand_format, data);
 307        strbuf_addch(&buf, '\n');
 308        batch_write(opt, buf.buf, buf.len);
 309        strbuf_release(&buf);
 310
 311        if (opt->print_contents) {
 312                print_object_or_die(opt, data);
 313                batch_write(opt, "\n", 1);
 314        }
 315        return 0;
 316}
 317
 318static int batch_objects(struct batch_options *opt)
 319{
 320        struct strbuf buf = STRBUF_INIT;
 321        struct expand_data data;
 322        int save_warning;
 323        int retval = 0;
 324
 325        if (!opt->format)
 326                opt->format = "%(objectname) %(objecttype) %(objectsize)";
 327
 328        /*
 329         * Expand once with our special mark_query flag, which will prime the
 330         * object_info to be handed to sha1_object_info_extended for each
 331         * object.
 332         */
 333        memset(&data, 0, sizeof(data));
 334        data.mark_query = 1;
 335        strbuf_expand(&buf, opt->format, expand_format, &data);
 336        data.mark_query = 0;
 337
 338        /*
 339         * If we are printing out the object, then always fill in the type,
 340         * since we will want to decide whether or not to stream.
 341         */
 342        if (opt->print_contents)
 343                data.info.typep = &data.type;
 344
 345        /*
 346         * We are going to call get_sha1 on a potentially very large number of
 347         * objects. In most large cases, these will be actual object sha1s. The
 348         * cost to double-check that each one is not also a ref (just so we can
 349         * warn) ends up dwarfing the actual cost of the object lookups
 350         * themselves. We can work around it by just turning off the warning.
 351         */
 352        save_warning = warn_on_object_refname_ambiguity;
 353        warn_on_object_refname_ambiguity = 0;
 354
 355        while (strbuf_getline(&buf, stdin, '\n') != EOF) {
 356                if (data.split_on_whitespace) {
 357                        /*
 358                         * Split at first whitespace, tying off the beginning
 359                         * of the string and saving the remainder (or NULL) in
 360                         * data.rest.
 361                         */
 362                        char *p = strpbrk(buf.buf, " \t");
 363                        if (p) {
 364                                while (*p && strchr(" \t", *p))
 365                                        *p++ = '\0';
 366                        }
 367                        data.rest = p;
 368                }
 369
 370                retval = batch_one_object(buf.buf, opt, &data);
 371                if (retval)
 372                        break;
 373        }
 374
 375        strbuf_release(&buf);
 376        warn_on_object_refname_ambiguity = save_warning;
 377        return retval;
 378}
 379
 380static const char * const cat_file_usage[] = {
 381        N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
 382        N_("git cat-file (--batch | --batch-check) [--follow-symlinks] < <list-of-objects>"),
 383        NULL
 384};
 385
 386static int git_cat_file_config(const char *var, const char *value, void *cb)
 387{
 388        if (userdiff_config(var, value) < 0)
 389                return -1;
 390
 391        return git_default_config(var, value, cb);
 392}
 393
 394static int batch_option_callback(const struct option *opt,
 395                                 const char *arg,
 396                                 int unset)
 397{
 398        struct batch_options *bo = opt->value;
 399
 400        if (bo->enabled) {
 401                return 1;
 402        }
 403
 404        bo->enabled = 1;
 405        bo->print_contents = !strcmp(opt->long_name, "batch");
 406        bo->format = arg;
 407
 408        return 0;
 409}
 410
 411int cmd_cat_file(int argc, const char **argv, const char *prefix)
 412{
 413        int opt = 0;
 414        const char *exp_type = NULL, *obj_name = NULL;
 415        struct batch_options batch = {0};
 416        int unknown_type = 0;
 417
 418        const struct option options[] = {
 419                OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 420                OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 421                OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 422                OPT_CMDMODE('e', NULL, &opt,
 423                            N_("exit with zero when there's no error"), 'e'),
 424                OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 425                OPT_CMDMODE(0, "textconv", &opt,
 426                            N_("for blob objects, run textconv on object's content"), 'c'),
 427                OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 428                          N_("allow -s and -t to work with broken/corrupt objects")),
 429                OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
 430                { OPTION_CALLBACK, 0, "batch", &batch, "format",
 431                        N_("show info and content of objects fed from the standard input"),
 432                        PARSE_OPT_OPTARG, batch_option_callback },
 433                { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 434                        N_("show info about objects fed from the standard input"),
 435                        PARSE_OPT_OPTARG, batch_option_callback },
 436                OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 437                         N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 438                OPT_END()
 439        };
 440
 441        git_config(git_cat_file_config, NULL);
 442
 443        argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
 444
 445        if (opt) {
 446                if (argc == 1)
 447                        obj_name = argv[0];
 448                else
 449                        usage_with_options(cat_file_usage, options);
 450        }
 451        if (!opt && !batch.enabled) {
 452                if (argc == 2) {
 453                        exp_type = argv[0];
 454                        obj_name = argv[1];
 455                } else
 456                        usage_with_options(cat_file_usage, options);
 457        }
 458        if (batch.enabled && (opt || argc)) {
 459                usage_with_options(cat_file_usage, options);
 460        }
 461
 462        if (batch.follow_symlinks && !batch.enabled) {
 463                usage_with_options(cat_file_usage, options);
 464        }
 465
 466        if (batch.enabled)
 467                return batch_objects(&batch);
 468
 469        if (unknown_type && opt != 't' && opt != 's')
 470                die("git cat-file --allow-unknown-type: use with -s or -t");
 471        return cat_one_file(opt, exp_type, obj_name, unknown_type);
 472}