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