Andrew's git - gitweb.git/blob - builtin/update-ref.c

   1#include "cache.h"
   2#include "refs.h"
   3#include "builtin.h"
   4#include "parse-options.h"
   5#include "quote.h"
   6#include "argv-array.h"
   7
   8static const char * const git_update_ref_usage[] = {
   9        N_("git update-ref [options] -d <refname> [<oldval>]"),
  10        N_("git update-ref [options]    <refname> <newval> [<oldval>]"),
  11        N_("git update-ref [options] --stdin [-z]"),
  12        NULL
  13};
  14
  15static char line_termination = '\n';
  16static int update_flags;
  17
  18/*
  19 * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  20 * and append the result to arg.  Return a pointer to the terminator.
  21 * Die if there is an error in how the argument is C-quoted.  This
  22 * function is only used if not -z.
  23 */
  24static const char *parse_arg(const char *next, struct strbuf *arg)
  25{
  26        if (*next == '"') {
  27                const char *orig = next;
  28
  29                if (unquote_c_style(arg, next, &next))
  30                        die("badly quoted argument: %s", orig);
  31                if (*next && !isspace(*next))
  32                        die("unexpected character after quoted argument: %s", orig);
  33        } else {
  34                while (*next && !isspace(*next))
  35                        strbuf_addch(arg, *next++);
  36        }
  37
  38        return next;
  39}
  40
  41/*
  42 * Parse the reference name immediately after "command SP".  If not
  43 * -z, then handle C-quoting.  Return a pointer to a newly allocated
  44 * string containing the name of the reference, or NULL if there was
  45 * an error.  Update *next to point at the character that terminates
  46 * the argument.  Die if C-quoting is malformed or the reference name
  47 * is invalid.
  48 */
  49static char *parse_refname(struct strbuf *input, const char **next)
  50{
  51        struct strbuf ref = STRBUF_INIT;
  52
  53        if (line_termination) {
  54                /* Without -z, use the next argument */
  55                *next = parse_arg(*next, &ref);
  56        } else {
  57                /* With -z, use everything up to the next NUL */
  58                strbuf_addstr(&ref, *next);
  59                *next += ref.len;
  60        }
  61
  62        if (!ref.len) {
  63                strbuf_release(&ref);
  64                return NULL;
  65        }
  66
  67        if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  68                die("invalid ref format: %s", ref.buf);
  69
  70        return strbuf_detach(&ref, NULL);
  71}
  72
  73/*
  74 * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  75 * difference affects which error messages are generated):
  76 */
  77#define PARSE_SHA1_OLD 0x01
  78
  79/*
  80 * For backwards compatibility, accept an empty string for update's
  81 * <newvalue> in binary mode to be equivalent to specifying zeros.
  82 */
  83#define PARSE_SHA1_ALLOW_EMPTY 0x02
  84
  85/*
  86 * Parse an argument separator followed by the next argument, if any.
  87 * If there is an argument, convert it to a SHA-1, write it to sha1,
  88 * set *next to point at the character terminating the argument, and
  89 * return 0.  If there is no argument at all (not even the empty
  90 * string), return 1 and leave *next unchanged.  If the value is
  91 * provided but cannot be converted to a SHA-1, die.  flags can
  92 * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
  93 */
  94static int parse_next_sha1(struct strbuf *input, const char **next,
  95                           unsigned char *sha1,
  96                           const char *command, const char *refname,
  97                           int flags)
  98{
  99        struct strbuf arg = STRBUF_INIT;
 100        int ret = 0;
 101
 102        if (*next == input->buf + input->len)
 103                goto eof;
 104
 105        if (line_termination) {
 106                /* Without -z, consume SP and use next argument */
 107                if (!**next || **next == line_termination)
 108                        return 1;
 109                if (**next != ' ')
 110                        die("%s %s: expected SP but got: %s",
 111                            command, refname, *next);
 112                (*next)++;
 113                *next = parse_arg(*next, &arg);
 114                if (arg.len) {
 115                        if (get_sha1(arg.buf, sha1))
 116                                goto invalid;
 117                } else {
 118                        /* Without -z, an empty value means all zeros: */
 119                        hashclr(sha1);
 120                }
 121        } else {
 122                /* With -z, read the next NUL-terminated line */
 123                if (**next)
 124                        die("%s %s: expected NUL but got: %s",
 125                            command, refname, *next);
 126                (*next)++;
 127                if (*next == input->buf + input->len)
 128                        goto eof;
 129                strbuf_addstr(&arg, *next);
 130                *next += arg.len;
 131
 132                if (arg.len) {
 133                        if (get_sha1(arg.buf, sha1))
 134                                goto invalid;
 135                } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 136                        /* With -z, treat an empty value as all zeros: */
 137                        warning("%s %s: missing <newvalue>, treating as zero",
 138                                command, refname);
 139                        hashclr(sha1);
 140                } else {
 141                        /*
 142                         * With -z, an empty non-required value means
 143                         * unspecified:
 144                         */
 145                        ret = 1;
 146                }
 147        }
 148
 149        strbuf_release(&arg);
 150
 151        return ret;
 152
 153 invalid:
 154        die(flags & PARSE_SHA1_OLD ?
 155            "%s %s: invalid <oldvalue>: %s" :
 156            "%s %s: invalid <newvalue>: %s",
 157            command, refname, arg.buf);
 158
 159 eof:
 160        die(flags & PARSE_SHA1_OLD ?
 161            "%s %s: unexpected end of input when reading <oldvalue>" :
 162            "%s %s: unexpected end of input when reading <newvalue>",
 163            command, refname);
 164}
 165
 166
 167/*
 168 * The following five parse_cmd_*() functions parse the corresponding
 169 * command.  In each case, next points at the character following the
 170 * command name and the following space.  They each return a pointer
 171 * to the character terminating the command, and die with an
 172 * explanatory message if there are any parsing problems.  All of
 173 * these functions handle either text or binary format input,
 174 * depending on how line_termination is set.
 175 */
 176
 177static const char *parse_cmd_update(struct ref_transaction *transaction,
 178                                    struct strbuf *input, const char *next)
 179{
 180        struct strbuf err = STRBUF_INIT;
 181        char *refname;
 182        unsigned char new_sha1[20];
 183        unsigned char old_sha1[20];
 184        int have_old;
 185
 186        refname = parse_refname(input, &next);
 187        if (!refname)
 188                die("update: missing <ref>");
 189
 190        if (parse_next_sha1(input, &next, new_sha1, "update", refname,
 191                            PARSE_SHA1_ALLOW_EMPTY))
 192                die("update %s: missing <newvalue>", refname);
 193
 194        have_old = !parse_next_sha1(input, &next, old_sha1, "update", refname,
 195                                    PARSE_SHA1_OLD);
 196
 197        if (*next != line_termination)
 198                die("update %s: extra input: %s", refname, next);
 199
 200        if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
 201                                   update_flags, have_old, &err))
 202                die("%s", err.buf);
 203
 204        update_flags = 0;
 205        free(refname);
 206        strbuf_release(&err);
 207
 208        return next;
 209}
 210
 211static const char *parse_cmd_create(struct ref_transaction *transaction,
 212                                    struct strbuf *input, const char *next)
 213{
 214        struct strbuf err = STRBUF_INIT;
 215        char *refname;
 216        unsigned char new_sha1[20];
 217
 218        refname = parse_refname(input, &next);
 219        if (!refname)
 220                die("create: missing <ref>");
 221
 222        if (parse_next_sha1(input, &next, new_sha1, "create", refname, 0))
 223                die("create %s: missing <newvalue>", refname);
 224
 225        if (is_null_sha1(new_sha1))
 226                die("create %s: zero <newvalue>", refname);
 227
 228        if (*next != line_termination)
 229                die("create %s: extra input: %s", refname, next);
 230
 231        if (ref_transaction_create(transaction, refname, new_sha1,
 232                                   update_flags, &err))
 233                die("%s", err.buf);
 234
 235        update_flags = 0;
 236        free(refname);
 237        strbuf_release(&err);
 238
 239        return next;
 240}
 241
 242static const char *parse_cmd_delete(struct ref_transaction *transaction,
 243                                    struct strbuf *input, const char *next)
 244{
 245        struct strbuf err = STRBUF_INIT;
 246        char *refname;
 247        unsigned char old_sha1[20];
 248        int have_old;
 249
 250        refname = parse_refname(input, &next);
 251        if (!refname)
 252                die("delete: missing <ref>");
 253
 254        if (parse_next_sha1(input, &next, old_sha1, "delete", refname,
 255                            PARSE_SHA1_OLD)) {
 256                have_old = 0;
 257        } else {
 258                if (is_null_sha1(old_sha1))
 259                        die("delete %s: zero <oldvalue>", refname);
 260                have_old = 1;
 261        }
 262
 263        if (*next != line_termination)
 264                die("delete %s: extra input: %s", refname, next);
 265
 266        if (ref_transaction_delete(transaction, refname, old_sha1,
 267                                   update_flags, have_old, &err))
 268                die("%s", err.buf);
 269
 270        update_flags = 0;
 271        free(refname);
 272        strbuf_release(&err);
 273
 274        return next;
 275}
 276
 277static const char *parse_cmd_verify(struct ref_transaction *transaction,
 278                                    struct strbuf *input, const char *next)
 279{
 280        struct strbuf err = STRBUF_INIT;
 281        char *refname;
 282        unsigned char new_sha1[20];
 283        unsigned char old_sha1[20];
 284        int have_old;
 285
 286        refname = parse_refname(input, &next);
 287        if (!refname)
 288                die("verify: missing <ref>");
 289
 290        if (parse_next_sha1(input, &next, old_sha1, "verify", refname,
 291                            PARSE_SHA1_OLD)) {
 292                hashclr(new_sha1);
 293                have_old = 0;
 294        } else {
 295                hashcpy(new_sha1, old_sha1);
 296                have_old = 1;
 297        }
 298
 299        if (*next != line_termination)
 300                die("verify %s: extra input: %s", refname, next);
 301
 302        if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
 303                                   update_flags, have_old, &err))
 304                die("%s", err.buf);
 305
 306        update_flags = 0;
 307        free(refname);
 308        strbuf_release(&err);
 309
 310        return next;
 311}
 312
 313static const char *parse_cmd_option(struct strbuf *input, const char *next)
 314{
 315        if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
 316                update_flags |= REF_NODEREF;
 317        else
 318                die("option unknown: %s", next);
 319        return next + 8;
 320}
 321
 322static void update_refs_stdin(struct ref_transaction *transaction)
 323{
 324        struct strbuf input = STRBUF_INIT;
 325        const char *next;
 326
 327        if (strbuf_read(&input, 0, 1000) < 0)
 328                die_errno("could not read from stdin");
 329        next = input.buf;
 330        /* Read each line dispatch its command */
 331        while (next < input.buf + input.len) {
 332                if (*next == line_termination)
 333                        die("empty command in input");
 334                else if (isspace(*next))
 335                        die("whitespace before command: %s", next);
 336                else if (starts_with(next, "update "))
 337                        next = parse_cmd_update(transaction, &input, next + 7);
 338                else if (starts_with(next, "create "))
 339                        next = parse_cmd_create(transaction, &input, next + 7);
 340                else if (starts_with(next, "delete "))
 341                        next = parse_cmd_delete(transaction, &input, next + 7);
 342                else if (starts_with(next, "verify "))
 343                        next = parse_cmd_verify(transaction, &input, next + 7);
 344                else if (starts_with(next, "option "))
 345                        next = parse_cmd_option(&input, next + 7);
 346                else
 347                        die("unknown command: %s", next);
 348
 349                next++;
 350        }
 351
 352        strbuf_release(&input);
 353}
 354
 355int cmd_update_ref(int argc, const char **argv, const char *prefix)
 356{
 357        const char *refname, *oldval, *msg = NULL;
 358        unsigned char sha1[20], oldsha1[20];
 359        int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0, flags = 0;
 360        struct option options[] = {
 361                OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 362                OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 363                OPT_BOOL( 0 , "no-deref", &no_deref,
 364                                        N_("update <refname> not the one it points to")),
 365                OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 366                OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 367                OPT_END(),
 368        };
 369
 370        git_config(git_default_config, NULL);
 371        argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 372                             0);
 373        if (msg && !*msg)
 374                die("Refusing to perform update with empty message.");
 375
 376        if (read_stdin) {
 377                struct strbuf err = STRBUF_INIT;
 378                struct ref_transaction *transaction;
 379
 380                transaction = ref_transaction_begin(&err);
 381                if (!transaction)
 382                        die("%s", err.buf);
 383                if (delete || no_deref || argc > 0)
 384                        usage_with_options(git_update_ref_usage, options);
 385                if (end_null)
 386                        line_termination = '\0';
 387                update_refs_stdin(transaction);
 388                if (ref_transaction_commit(transaction, msg, &err))
 389                        die("%s", err.buf);
 390                ref_transaction_free(transaction);
 391                strbuf_release(&err);
 392                return 0;
 393        }
 394
 395        if (end_null)
 396                usage_with_options(git_update_ref_usage, options);
 397
 398        if (delete) {
 399                if (argc < 1 || argc > 2)
 400                        usage_with_options(git_update_ref_usage, options);
 401                refname = argv[0];
 402                oldval = argv[1];
 403        } else {
 404                const char *value;
 405                if (argc < 2 || argc > 3)
 406                        usage_with_options(git_update_ref_usage, options);
 407                refname = argv[0];
 408                value = argv[1];
 409                oldval = argv[2];
 410                if (get_sha1(value, sha1))
 411                        die("%s: not a valid SHA1", value);
 412        }
 413
 414        hashclr(oldsha1); /* all-zero hash in case oldval is the empty string */
 415        if (oldval && *oldval && get_sha1(oldval, oldsha1))
 416                die("%s: not a valid old SHA1", oldval);
 417
 418        if (no_deref)
 419                flags = REF_NODEREF;
 420        if (delete)
 421                return delete_ref(refname, oldval ? oldsha1 : NULL, flags);
 422        else
 423                return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
 424                                  flags, UPDATE_REFS_DIE_ON_ERR);
 425}