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