reftable/record.c

   1 /*
   2 Copyright 2020 Google LLC
   3
   4 Use of this source code is governed by a BSD-style
   5 license that can be found in the LICENSE file or at
   6 https://developers.google.com/open-source/licenses/bsd
   7 */
   8
   9 /* record.c - methods for different types of records. */
  10
  11 #include "record.h"
  12
  13 #include "system.h"
  14 #include "constants.h"
  15 #include "reftable-error.h"
  16 #include "basics.h"
  17
  18 static struct reftable_record_vtable *
  19 reftable_record_vtable(struct reftable_record *rec);
  20 static void *reftable_record_data(struct reftable_record *rec);
  21
  22 int get_var_int(uint64_t *dest, struct string_view *in)
  23 {
  24         int ptr = 0;
  25         uint64_t val;
  26
  27         if (in->len == 0)
  28                 return -1;
  29         val = in->buf[ptr] & 0x7f;
  30
  31         while (in->buf[ptr] & 0x80) {
  32                 ptr++;
  33                 if (ptr > in->len) {
  34                         return -1;
  35                 }
  36                 val = (val + 1) << 7 | (uint64_t)(in->buf[ptr] & 0x7f);
  37         }
  38
  39         *dest = val;
  40         return ptr + 1;
  41 }
  42
  43 int put_var_int(struct string_view *dest, uint64_t val)
  44 {
  45         uint8_t buf[10] = { 0 };
  46         int i = 9;
  47         int n = 0;
  48         buf[i] = (uint8_t)(val & 0x7f);
  49         i--;
  50         while (1) {
  51                 val >>= 7;
  52                 if (!val) {
  53                         break;
  54                 }
  55                 val--;
  56                 buf[i] = 0x80 | (uint8_t)(val & 0x7f);
  57                 i--;
  58         }
  59
  60         n = sizeof(buf) - i - 1;
  61         if (dest->len < n)
  62                 return -1;
  63         memcpy(dest->buf, &buf[i + 1], n);
  64         return n;
  65 }
  66
  67 int reftable_is_block_type(uint8_t typ)
  68 {
  69         switch (typ) {
  70         case BLOCK_TYPE_REF:
  71         case BLOCK_TYPE_LOG:
  72         case BLOCK_TYPE_OBJ:
  73         case BLOCK_TYPE_INDEX:
  74                 return 1;
  75         }
  76         return 0;
  77 }
  78
  79 const unsigned char *reftable_ref_record_val1(const struct reftable_ref_record *rec)
  80 {
  81         switch (rec->value_type) {
  82         case REFTABLE_REF_VAL1:
  83                 return rec->value.val1;
  84         case REFTABLE_REF_VAL2:
  85                 return rec->value.val2.value;
  86         default:
  87                 return NULL;
  88         }
  89 }
  90
  91 const unsigned char *reftable_ref_record_val2(const struct reftable_ref_record *rec)
  92 {
  93         switch (rec->value_type) {
  94         case REFTABLE_REF_VAL2:
  95                 return rec->value.val2.target_value;
  96         default:
  97                 return NULL;
  98         }
  99 }
 100
 101 static int decode_string(struct strbuf *dest, struct string_view in)
 102 {
 103         int start_len = in.len;
 104         uint64_t tsize = 0;
 105         int n = get_var_int(&tsize, &in);
 106         if (n <= 0)
 107                 return -1;
 108         string_view_consume(&in, n);
 109         if (in.len < tsize)
 110                 return -1;
 111
 112         strbuf_reset(dest);
 113         strbuf_add(dest, in.buf, tsize);
 114         string_view_consume(&in, tsize);
 115
 116         return start_len - in.len;
 117 }
 118
 119 static int encode_string(char *str, struct string_view s)
 120 {
 121         struct string_view start = s;
 122         int l = strlen(str);
 123         int n = put_var_int(&s, l);
 124         if (n < 0)
 125                 return -1;
 126         string_view_consume(&s, n);
 127         if (s.len < l)
 128                 return -1;
 129         memcpy(s.buf, str, l);
 130         string_view_consume(&s, l);
 131
 132         return start.len - s.len;
 133 }
 134
 135 int reftable_encode_key(int *restart, struct string_view dest,
 136                         struct strbuf prev_key, struct strbuf key,
 137                         uint8_t extra)
 138 {
 139         struct string_view start = dest;
 140         int prefix_len = common_prefix_size(&prev_key, &key);
 141         uint64_t suffix_len = key.len - prefix_len;
 142         int n = put_var_int(&dest, (uint64_t)prefix_len);
 143         if (n < 0)
 144                 return -1;
 145         string_view_consume(&dest, n);
 146
 147         *restart = (prefix_len == 0);
 148
 149         n = put_var_int(&dest, suffix_len << 3 | (uint64_t)extra);
 150         if (n < 0)
 151                 return -1;
 152         string_view_consume(&dest, n);
 153
 154         if (dest.len < suffix_len)
 155                 return -1;
 156         memcpy(dest.buf, key.buf + prefix_len, suffix_len);
 157         string_view_consume(&dest, suffix_len);
 158
 159         return start.len - dest.len;
 160 }
 161
 162 int reftable_decode_key(struct strbuf *key, uint8_t *extra,
 163                         struct strbuf last_key, struct string_view in)
 164 {
 165         int start_len = in.len;
 166         uint64_t prefix_len = 0;
 167         uint64_t suffix_len = 0;
 168         int n = get_var_int(&prefix_len, &in);
 169         if (n < 0)
 170                 return -1;
 171         string_view_consume(&in, n);
 172
 173         if (prefix_len > last_key.len)
 174                 return -1;
 175
 176         n = get_var_int(&suffix_len, &in);
 177         if (n <= 0)
 178                 return -1;
 179         string_view_consume(&in, n);
 180
 181         *extra = (uint8_t)(suffix_len & 0x7);
 182         suffix_len >>= 3;
 183
 184         if (in.len < suffix_len)
 185                 return -1;
 186
 187         strbuf_reset(key);
 188         strbuf_add(key, last_key.buf, prefix_len);
 189         strbuf_add(key, in.buf, suffix_len);
 190         string_view_consume(&in, suffix_len);
 191
 192         return start_len - in.len;
 193 }
 194
 195 static void reftable_ref_record_key(const void *r, struct strbuf *dest)
 196 {
 197         const struct reftable_ref_record *rec =
 198                 (const struct reftable_ref_record *)r;
 199         strbuf_reset(dest);
 200         strbuf_addstr(dest, rec->refname);
 201 }
 202
 203 static void reftable_ref_record_copy_from(void *rec, const void *src_rec,
 204                                           int hash_size)
 205 {
 206         struct reftable_ref_record *ref = rec;
 207         const struct reftable_ref_record *src = src_rec;
 208         assert(hash_size > 0);
 209
 210         /* This is simple and correct, but we could probably reuse the hash
 211          * fields. */
 212         reftable_ref_record_release(ref);
 213         if (src->refname) {
 214                 ref->refname = xstrdup(src->refname);
 215         }
 216         ref->update_index = src->update_index;
 217         ref->value_type = src->value_type;
 218         switch (src->value_type) {
 219         case REFTABLE_REF_DELETION:
 220                 break;
 221         case REFTABLE_REF_VAL1:
 222                 memcpy(ref->value.val1, src->value.val1, hash_size);
 223                 break;
 224         case REFTABLE_REF_VAL2:
 225                 memcpy(ref->value.val2.value, src->value.val2.value, hash_size);
 226                 memcpy(ref->value.val2.target_value,
 227                        src->value.val2.target_value, hash_size);
 228                 break;
 229         case REFTABLE_REF_SYMREF:
 230                 ref->value.symref = xstrdup(src->value.symref);
 231                 break;
 232         }
 233 }
 234
 235 static char hexdigit(int c)
 236 {
 237         if (c <= 9)
 238                 return '0' + c;
 239         return 'a' + (c - 10);
 240 }
 241
 242 static void hex_format(char *dest, const unsigned char *src, int hash_size)
 243 {
 244         assert(hash_size > 0);
 245         if (src) {
 246                 int i = 0;
 247                 for (i = 0; i < hash_size; i++) {
 248                         dest[2 * i] = hexdigit(src[i] >> 4);
 249                         dest[2 * i + 1] = hexdigit(src[i] & 0xf);
 250                 }
 251                 dest[2 * hash_size] = 0;
 252         }
 253 }
 254
 255 static void reftable_ref_record_print_sz(const struct reftable_ref_record *ref,
 256                                          int hash_size)
 257 {
 258         char hex[GIT_MAX_HEXSZ + 1] = { 0 }; /* BUG */
 259         printf("ref{%s(%" PRIu64 ") ", ref->refname, ref->update_index);
 260         switch (ref->value_type) {
 261         case REFTABLE_REF_SYMREF:
 262                 printf("=> %s", ref->value.symref);
 263                 break;
 264         case REFTABLE_REF_VAL2:
 265                 hex_format(hex, ref->value.val2.value, hash_size);
 266                 printf("val 2 %s", hex);
 267                 hex_format(hex, ref->value.val2.target_value,
 268                            hash_size);
 269                 printf("(T %s)", hex);
 270                 break;
 271         case REFTABLE_REF_VAL1:
 272                 hex_format(hex, ref->value.val1, hash_size);
 273                 printf("val 1 %s", hex);
 274                 break;
 275         case REFTABLE_REF_DELETION:
 276                 printf("delete");
 277                 break;
 278         }
 279         printf("}\n");
 280 }
 281
 282 void reftable_ref_record_print(const struct reftable_ref_record *ref,
 283                                uint32_t hash_id) {
 284         reftable_ref_record_print_sz(ref, hash_size(hash_id));
 285 }
 286
 287 static void reftable_ref_record_release_void(void *rec)
 288 {
 289         reftable_ref_record_release(rec);
 290 }
 291
 292 void reftable_ref_record_release(struct reftable_ref_record *ref)
 293 {
 294         switch (ref->value_type) {
 295         case REFTABLE_REF_SYMREF:
 296                 reftable_free(ref->value.symref);
 297                 break;
 298         case REFTABLE_REF_VAL2:
 299                 break;
 300         case REFTABLE_REF_VAL1:
 301                 break;
 302         case REFTABLE_REF_DELETION:
 303                 break;
 304         default:
 305                 abort();
 306         }
 307
 308         reftable_free(ref->refname);
 309         memset(ref, 0, sizeof(struct reftable_ref_record));
 310 }
 311
 312 static uint8_t reftable_ref_record_val_type(const void *rec)
 313 {
 314         const struct reftable_ref_record *r =
 315                 (const struct reftable_ref_record *)rec;
 316         return r->value_type;
 317 }
 318
 319 static int reftable_ref_record_encode(const void *rec, struct string_view s,
 320                                       int hash_size)
 321 {
 322         const struct reftable_ref_record *r =
 323                 (const struct reftable_ref_record *)rec;
 324         struct string_view start = s;
 325         int n = put_var_int(&s, r->update_index);
 326         assert(hash_size > 0);
 327         if (n < 0)
 328                 return -1;
 329         string_view_consume(&s, n);
 330
 331         switch (r->value_type) {
 332         case REFTABLE_REF_SYMREF:
 333                 n = encode_string(r->value.symref, s);
 334                 if (n < 0) {
 335                         return -1;
 336                 }
 337                 string_view_consume(&s, n);
 338                 break;
 339         case REFTABLE_REF_VAL2:
 340                 if (s.len < 2 * hash_size) {
 341                         return -1;
 342                 }
 343                 memcpy(s.buf, r->value.val2.value, hash_size);
 344                 string_view_consume(&s, hash_size);
 345                 memcpy(s.buf, r->value.val2.target_value, hash_size);
 346                 string_view_consume(&s, hash_size);
 347                 break;
 348         case REFTABLE_REF_VAL1:
 349                 if (s.len < hash_size) {
 350                         return -1;
 351                 }
 352                 memcpy(s.buf, r->value.val1, hash_size);
 353                 string_view_consume(&s, hash_size);
 354                 break;
 355         case REFTABLE_REF_DELETION:
 356                 break;
 357         default:
 358                 abort();
 359         }
 360
 361         return start.len - s.len;
 362 }
 363
 364 static int reftable_ref_record_decode(void *rec, struct strbuf key,
 365                                       uint8_t val_type, struct string_view in,
 366                                       int hash_size)
 367 {
 368         struct reftable_ref_record *r = rec;
 369         struct string_view start = in;
 370         uint64_t update_index = 0;
 371         int n = get_var_int(&update_index, &in);
 372         if (n < 0)
 373                 return n;
 374         string_view_consume(&in, n);
 375
 376         reftable_ref_record_release(r);
 377
 378         assert(hash_size > 0);
 379
 380         r->refname = reftable_realloc(r->refname, key.len + 1);
 381         memcpy(r->refname, key.buf, key.len);
 382         r->update_index = update_index;
 383         r->refname[key.len] = 0;
 384         r->value_type = val_type;
 385         switch (val_type) {
 386         case REFTABLE_REF_VAL1:
 387                 if (in.len < hash_size) {
 388                         return -1;
 389                 }
 390
 391                 memcpy(r->value.val1, in.buf, hash_size);
 392                 string_view_consume(&in, hash_size);
 393                 break;
 394
 395         case REFTABLE_REF_VAL2:
 396                 if (in.len < 2 * hash_size) {
 397                         return -1;
 398                 }
 399
 400                 memcpy(r->value.val2.value, in.buf, hash_size);
 401                 string_view_consume(&in, hash_size);
 402
 403                 memcpy(r->value.val2.target_value, in.buf, hash_size);
 404                 string_view_consume(&in, hash_size);
 405                 break;
 406
 407         case REFTABLE_REF_SYMREF: {
 408                 struct strbuf dest = STRBUF_INIT;
 409                 int n = decode_string(&dest, in);
 410                 if (n < 0) {
 411                         return -1;
 412                 }
 413                 string_view_consume(&in, n);
 414                 r->value.symref = dest.buf;
 415         } break;
 416
 417         case REFTABLE_REF_DELETION:
 418                 break;
 419         default:
 420                 abort();
 421                 break;
 422         }
 423
 424         return start.len - in.len;
 425 }
 426
 427 static int reftable_ref_record_is_deletion_void(const void *p)
 428 {
 429         return reftable_ref_record_is_deletion(
 430                 (const struct reftable_ref_record *)p);
 431 }
 432
 433
 434 static int reftable_ref_record_equal_void(const void *a,
 435                                           const void *b, int hash_size)
 436 {
 437         struct reftable_ref_record *ra = (struct reftable_ref_record *) a;
 438         struct reftable_ref_record *rb = (struct reftable_ref_record *) b;
 439         return reftable_ref_record_equal(ra, rb, hash_size);
 440 }
 441
 442 static void reftable_ref_record_print_void(const void *rec,
 443                                            int hash_size)
 444 {
 445         reftable_ref_record_print_sz((struct reftable_ref_record *) rec, hash_size);
 446 }
 447
 448 static struct reftable_record_vtable reftable_ref_record_vtable = {
 449         .key = &reftable_ref_record_key,
 450         .type = BLOCK_TYPE_REF,
 451         .copy_from = &reftable_ref_record_copy_from,
 452         .val_type = &reftable_ref_record_val_type,
 453         .encode = &reftable_ref_record_encode,
 454         .decode = &reftable_ref_record_decode,
 455         .release = &reftable_ref_record_release_void,
 456         .is_deletion = &reftable_ref_record_is_deletion_void,
 457         .equal = &reftable_ref_record_equal_void,
 458         .print = &reftable_ref_record_print_void,
 459 };
 460
 461 static void reftable_obj_record_key(const void *r, struct strbuf *dest)
 462 {
 463         const struct reftable_obj_record *rec =
 464                 (const struct reftable_obj_record *)r;
 465         strbuf_reset(dest);
 466         strbuf_add(dest, rec->hash_prefix, rec->hash_prefix_len);
 467 }
 468
 469 static void reftable_obj_record_release(void *rec)
 470 {
 471         struct reftable_obj_record *obj = rec;
 472         FREE_AND_NULL(obj->hash_prefix);
 473         FREE_AND_NULL(obj->offsets);
 474         memset(obj, 0, sizeof(struct reftable_obj_record));
 475 }
 476
 477 static void reftable_obj_record_print(const void *rec, int hash_size)
 478 {
 479         const struct reftable_obj_record *obj = rec;
 480         char hex[GIT_MAX_HEXSZ + 1] = { 0 };
 481         struct strbuf offset_str = STRBUF_INIT;
 482         int i;
 483
 484         for (i = 0; i < obj->offset_len; i++)
 485                 strbuf_addf(&offset_str, "%" PRIu64 " ", obj->offsets[i]);
 486         hex_format(hex, obj->hash_prefix, obj->hash_prefix_len);
 487         printf("prefix %s (len %d), offsets [%s]\n",
 488                hex, obj->hash_prefix_len, offset_str.buf);
 489         strbuf_release(&offset_str);
 490 }
 491
 492 static void reftable_obj_record_copy_from(void *rec, const void *src_rec,
 493                                           int hash_size)
 494 {
 495         struct reftable_obj_record *obj = rec;
 496         const struct reftable_obj_record *src =
 497                 (const struct reftable_obj_record *)src_rec;
 498
 499         reftable_obj_record_release(obj);
 500         obj->hash_prefix = reftable_malloc(src->hash_prefix_len);
 501         obj->hash_prefix_len = src->hash_prefix_len;
 502         if (src->hash_prefix_len)
 503                 memcpy(obj->hash_prefix, src->hash_prefix, obj->hash_prefix_len);
 504
 505         obj->offsets = reftable_malloc(src->offset_len * sizeof(uint64_t));
 506         obj->offset_len = src->offset_len;
 507         COPY_ARRAY(obj->offsets, src->offsets, src->offset_len);
 508 }
 509
 510 static uint8_t reftable_obj_record_val_type(const void *rec)
 511 {
 512         const struct reftable_obj_record *r = rec;
 513         if (r->offset_len > 0 && r->offset_len < 8)
 514                 return r->offset_len;
 515         return 0;
 516 }
 517
 518 static int reftable_obj_record_encode(const void *rec, struct string_view s,
 519                                       int hash_size)
 520 {
 521         const struct reftable_obj_record *r = rec;
 522         struct string_view start = s;
 523         int i = 0;
 524         int n = 0;
 525         uint64_t last = 0;
 526         if (r->offset_len == 0 || r->offset_len >= 8) {
 527                 n = put_var_int(&s, r->offset_len);
 528                 if (n < 0) {
 529                         return -1;
 530                 }
 531                 string_view_consume(&s, n);
 532         }
 533         if (r->offset_len == 0)
 534                 return start.len - s.len;
 535         n = put_var_int(&s, r->offsets[0]);
 536         if (n < 0)
 537                 return -1;
 538         string_view_consume(&s, n);
 539
 540         last = r->offsets[0];
 541         for (i = 1; i < r->offset_len; i++) {
 542                 int n = put_var_int(&s, r->offsets[i] - last);
 543                 if (n < 0) {
 544                         return -1;
 545                 }
 546                 string_view_consume(&s, n);
 547                 last = r->offsets[i];
 548         }
 549         return start.len - s.len;
 550 }
 551
 552 static int reftable_obj_record_decode(void *rec, struct strbuf key,
 553                                       uint8_t val_type, struct string_view in,
 554                                       int hash_size)
 555 {
 556         struct string_view start = in;
 557         struct reftable_obj_record *r = rec;
 558         uint64_t count = val_type;
 559         int n = 0;
 560         uint64_t last;
 561         int j;
 562         r->hash_prefix = reftable_malloc(key.len);
 563         memcpy(r->hash_prefix, key.buf, key.len);
 564         r->hash_prefix_len = key.len;
 565
 566         if (val_type == 0) {
 567                 n = get_var_int(&count, &in);
 568                 if (n < 0) {
 569                         return n;
 570                 }
 571
 572                 string_view_consume(&in, n);
 573         }
 574
 575         r->offsets = NULL;
 576         r->offset_len = 0;
 577         if (count == 0)
 578                 return start.len - in.len;
 579
 580         r->offsets = reftable_malloc(count * sizeof(uint64_t));
 581         r->offset_len = count;
 582
 583         n = get_var_int(&r->offsets[0], &in);
 584         if (n < 0)
 585                 return n;
 586         string_view_consume(&in, n);
 587
 588         last = r->offsets[0];
 589         j = 1;
 590         while (j < count) {
 591                 uint64_t delta = 0;
 592                 int n = get_var_int(&delta, &in);
 593                 if (n < 0) {
 594                         return n;
 595                 }
 596                 string_view_consume(&in, n);
 597
 598                 last = r->offsets[j] = (delta + last);
 599                 j++;
 600         }
 601         return start.len - in.len;
 602 }
 603
 604 static int not_a_deletion(const void *p)
 605 {
 606         return 0;
 607 }
 608
 609 static int reftable_obj_record_equal_void(const void *a, const void *b, int hash_size)
 610 {
 611         struct reftable_obj_record *ra = (struct reftable_obj_record *) a;
 612         struct reftable_obj_record *rb = (struct reftable_obj_record *) b;
 613
 614         if (ra->hash_prefix_len != rb->hash_prefix_len
 615             || ra->offset_len != rb->offset_len)
 616                 return 0;
 617
 618         if (ra->hash_prefix_len &&
 619             memcmp(ra->hash_prefix, rb->hash_prefix, ra->hash_prefix_len))
 620                 return 0;
 621         if (ra->offset_len &&
 622             memcmp(ra->offsets, rb->offsets, ra->offset_len * sizeof(uint64_t)))
 623                 return 0;
 624
 625         return 1;
 626 }
 627
 628 static struct reftable_record_vtable reftable_obj_record_vtable = {
 629         .key = &reftable_obj_record_key,
 630         .type = BLOCK_TYPE_OBJ,
 631         .copy_from = &reftable_obj_record_copy_from,
 632         .val_type = &reftable_obj_record_val_type,
 633         .encode = &reftable_obj_record_encode,
 634         .decode = &reftable_obj_record_decode,
 635         .release = &reftable_obj_record_release,
 636         .is_deletion = &not_a_deletion,
 637         .equal = &reftable_obj_record_equal_void,
 638         .print = &reftable_obj_record_print,
 639 };
 640
 641 static void reftable_log_record_print_sz(struct reftable_log_record *log,
 642                                          int hash_size)
 643 {
 644         char hex[GIT_MAX_HEXSZ + 1] = { 0 };
 645
 646         switch (log->value_type) {
 647         case REFTABLE_LOG_DELETION:
 648                 printf("log{%s(%" PRIu64 ") delete\n", log->refname,
 649                        log->update_index);
 650                 break;
 651         case REFTABLE_LOG_UPDATE:
 652                 printf("log{%s(%" PRIu64 ") %s <%s> %" PRIu64 " %04d\n",
 653                        log->refname, log->update_index,
 654                        log->value.update.name ? log->value.update.name : "",
 655                        log->value.update.email ? log->value.update.email : "",
 656                        log->value.update.time,
 657                        log->value.update.tz_offset);
 658                 hex_format(hex, log->value.update.old_hash, hash_size);
 659                 printf("%s => ", hex);
 660                 hex_format(hex, log->value.update.new_hash, hash_size);
 661                 printf("%s\n\n%s\n}\n", hex,
 662                        log->value.update.message ? log->value.update.message : "");
 663                 break;
 664         }
 665 }
 666
 667 void reftable_log_record_print(struct reftable_log_record *log,
 668                                       uint32_t hash_id)
 669 {
 670         reftable_log_record_print_sz(log, hash_size(hash_id));
 671 }
 672
 673 static void reftable_log_record_key(const void *r, struct strbuf *dest)
 674 {
 675         const struct reftable_log_record *rec =
 676                 (const struct reftable_log_record *)r;
 677         int len = strlen(rec->refname);
 678         uint8_t i64[8];
 679         uint64_t ts = 0;
 680         strbuf_reset(dest);
 681         strbuf_add(dest, (uint8_t *)rec->refname, len + 1);
 682
 683         ts = (~ts) - rec->update_index;
 684         put_be64(&i64[0], ts);
 685         strbuf_add(dest, i64, sizeof(i64));
 686 }
 687
 688 static void reftable_log_record_copy_from(void *rec, const void *src_rec,
 689                                           int hash_size)
 690 {
 691         struct reftable_log_record *dst = rec;
 692         const struct reftable_log_record *src =
 693                 (const struct reftable_log_record *)src_rec;
 694
 695         reftable_log_record_release(dst);
 696         *dst = *src;
 697         if (dst->refname) {
 698                 dst->refname = xstrdup(dst->refname);
 699         }
 700         switch (dst->value_type) {
 701         case REFTABLE_LOG_DELETION:
 702                 break;
 703         case REFTABLE_LOG_UPDATE:
 704                 if (dst->value.update.email) {
 705                         dst->value.update.email =
 706                                 xstrdup(dst->value.update.email);
 707                 }
 708                 if (dst->value.update.name) {
 709                         dst->value.update.name =
 710                                 xstrdup(dst->value.update.name);
 711                 }
 712                 if (dst->value.update.message) {
 713                         dst->value.update.message =
 714                                 xstrdup(dst->value.update.message);
 715                 }
 716
 717                 if (dst->value.update.new_hash) {
 718                         dst->value.update.new_hash = reftable_malloc(hash_size);
 719                         memcpy(dst->value.update.new_hash,
 720                                src->value.update.new_hash, hash_size);
 721                 }
 722                 if (dst->value.update.old_hash) {
 723                         dst->value.update.old_hash = reftable_malloc(hash_size);
 724                         memcpy(dst->value.update.old_hash,
 725                                src->value.update.old_hash, hash_size);
 726                 }
 727                 break;
 728         }
 729 }
 730
 731 static void reftable_log_record_release_void(void *rec)
 732 {
 733         struct reftable_log_record *r = rec;
 734         reftable_log_record_release(r);
 735 }
 736
 737 void reftable_log_record_release(struct reftable_log_record *r)
 738 {
 739         reftable_free(r->refname);
 740         switch (r->value_type) {
 741         case REFTABLE_LOG_DELETION:
 742                 break;
 743         case REFTABLE_LOG_UPDATE:
 744                 reftable_free(r->value.update.new_hash);
 745                 reftable_free(r->value.update.old_hash);
 746                 reftable_free(r->value.update.name);
 747                 reftable_free(r->value.update.email);
 748                 reftable_free(r->value.update.message);
 749                 break;
 750         }
 751         memset(r, 0, sizeof(struct reftable_log_record));
 752 }
 753
 754 static uint8_t reftable_log_record_val_type(const void *rec)
 755 {
 756         const struct reftable_log_record *log =
 757                 (const struct reftable_log_record *)rec;
 758
 759         return reftable_log_record_is_deletion(log) ? 0 : 1;
 760 }
 761
 762 static uint8_t zero[GIT_SHA256_RAWSZ] = { 0 };
 763
 764 static int reftable_log_record_encode(const void *rec, struct string_view s,
 765                                       int hash_size)
 766 {
 767         const struct reftable_log_record *r = rec;
 768         struct string_view start = s;
 769         int n = 0;
 770         uint8_t *oldh = NULL;
 771         uint8_t *newh = NULL;
 772         if (reftable_log_record_is_deletion(r))
 773                 return 0;
 774
 775         oldh = r->value.update.old_hash;
 776         newh = r->value.update.new_hash;
 777         if (!oldh) {
 778                 oldh = zero;
 779         }
 780         if (!newh) {
 781                 newh = zero;
 782         }
 783
 784         if (s.len < 2 * hash_size)
 785                 return -1;
 786
 787         memcpy(s.buf, oldh, hash_size);
 788         memcpy(s.buf + hash_size, newh, hash_size);
 789         string_view_consume(&s, 2 * hash_size);
 790
 791         n = encode_string(r->value.update.name ? r->value.update.name : "", s);
 792         if (n < 0)
 793                 return -1;
 794         string_view_consume(&s, n);
 795
 796         n = encode_string(r->value.update.email ? r->value.update.email : "",
 797                           s);
 798         if (n < 0)
 799                 return -1;
 800         string_view_consume(&s, n);
 801
 802         n = put_var_int(&s, r->value.update.time);
 803         if (n < 0)
 804                 return -1;
 805         string_view_consume(&s, n);
 806
 807         if (s.len < 2)
 808                 return -1;
 809
 810         put_be16(s.buf, r->value.update.tz_offset);
 811         string_view_consume(&s, 2);
 812
 813         n = encode_string(
 814                 r->value.update.message ? r->value.update.message : "", s);
 815         if (n < 0)
 816                 return -1;
 817         string_view_consume(&s, n);
 818
 819         return start.len - s.len;
 820 }
 821
 822 static int reftable_log_record_decode(void *rec, struct strbuf key,
 823                                       uint8_t val_type, struct string_view in,
 824                                       int hash_size)
 825 {
 826         struct string_view start = in;
 827         struct reftable_log_record *r = rec;
 828         uint64_t max = 0;
 829         uint64_t ts = 0;
 830         struct strbuf dest = STRBUF_INIT;
 831         int n;
 832
 833         if (key.len <= 9 || key.buf[key.len - 9] != 0)
 834                 return REFTABLE_FORMAT_ERROR;
 835
 836         r->refname = reftable_realloc(r->refname, key.len - 8);
 837         memcpy(r->refname, key.buf, key.len - 8);
 838         ts = get_be64(key.buf + key.len - 8);
 839
 840         r->update_index = (~max) - ts;
 841
 842         if (val_type != r->value_type) {
 843                 switch (r->value_type) {
 844                 case REFTABLE_LOG_UPDATE:
 845                         FREE_AND_NULL(r->value.update.old_hash);
 846                         FREE_AND_NULL(r->value.update.new_hash);
 847                         FREE_AND_NULL(r->value.update.message);
 848                         FREE_AND_NULL(r->value.update.email);
 849                         FREE_AND_NULL(r->value.update.name);
 850                         break;
 851                 case REFTABLE_LOG_DELETION:
 852                         break;
 853                 }
 854         }
 855
 856         r->value_type = val_type;
 857         if (val_type == REFTABLE_LOG_DELETION)
 858                 return 0;
 859
 860         if (in.len < 2 * hash_size)
 861                 return REFTABLE_FORMAT_ERROR;
 862
 863         r->value.update.old_hash =
 864                 reftable_realloc(r->value.update.old_hash, hash_size);
 865         r->value.update.new_hash =
 866                 reftable_realloc(r->value.update.new_hash, hash_size);
 867
 868         memcpy(r->value.update.old_hash, in.buf, hash_size);
 869         memcpy(r->value.update.new_hash, in.buf + hash_size, hash_size);
 870
 871         string_view_consume(&in, 2 * hash_size);
 872
 873         n = decode_string(&dest, in);
 874         if (n < 0)
 875                 goto done;
 876         string_view_consume(&in, n);
 877
 878         r->value.update.name =
 879                 reftable_realloc(r->value.update.name, dest.len + 1);
 880         memcpy(r->value.update.name, dest.buf, dest.len);
 881         r->value.update.name[dest.len] = 0;
 882
 883         strbuf_reset(&dest);
 884         n = decode_string(&dest, in);
 885         if (n < 0)
 886                 goto done;
 887         string_view_consume(&in, n);
 888
 889         r->value.update.email =
 890                 reftable_realloc(r->value.update.email, dest.len + 1);
 891         memcpy(r->value.update.email, dest.buf, dest.len);
 892         r->value.update.email[dest.len] = 0;
 893
 894         ts = 0;
 895         n = get_var_int(&ts, &in);
 896         if (n < 0)
 897                 goto done;
 898         string_view_consume(&in, n);
 899         r->value.update.time = ts;
 900         if (in.len < 2)
 901                 goto done;
 902
 903         r->value.update.tz_offset = get_be16(in.buf);
 904         string_view_consume(&in, 2);
 905
 906         strbuf_reset(&dest);
 907         n = decode_string(&dest, in);
 908         if (n < 0)
 909                 goto done;
 910         string_view_consume(&in, n);
 911
 912         r->value.update.message =
 913                 reftable_realloc(r->value.update.message, dest.len + 1);
 914         memcpy(r->value.update.message, dest.buf, dest.len);
 915         r->value.update.message[dest.len] = 0;
 916
 917         strbuf_release(&dest);
 918         return start.len - in.len;
 919
 920 done:
 921         strbuf_release(&dest);
 922         return REFTABLE_FORMAT_ERROR;
 923 }
 924
 925 static int null_streq(char *a, char *b)
 926 {
 927         char *empty = "";
 928         if (!a)
 929                 a = empty;
 930
 931         if (!b)
 932                 b = empty;
 933
 934         return 0 == strcmp(a, b);
 935 }
 936
 937 static int zero_hash_eq(uint8_t *a, uint8_t *b, int sz)
 938 {
 939         if (!a)
 940                 a = zero;
 941
 942         if (!b)
 943                 b = zero;
 944
 945         return !memcmp(a, b, sz);
 946 }
 947
 948 static int reftable_log_record_equal_void(const void *a,
 949                                           const void *b, int hash_size)
 950 {
 951         return reftable_log_record_equal((struct reftable_log_record *) a,
 952                                          (struct reftable_log_record *) b,
 953                                          hash_size);
 954 }
 955
 956 int reftable_log_record_equal(const struct reftable_log_record *a,
 957                               const struct reftable_log_record *b, int hash_size)
 958 {
 959         if (!(null_streq(a->refname, b->refname) &&
 960               a->update_index == b->update_index &&
 961               a->value_type == b->value_type))
 962                 return 0;
 963
 964         switch (a->value_type) {
 965         case REFTABLE_LOG_DELETION:
 966                 return 1;
 967         case REFTABLE_LOG_UPDATE:
 968                 return null_streq(a->value.update.name, b->value.update.name) &&
 969                        a->value.update.time == b->value.update.time &&
 970                        a->value.update.tz_offset == b->value.update.tz_offset &&
 971                        null_streq(a->value.update.email,
 972                                   b->value.update.email) &&
 973                        null_streq(a->value.update.message,
 974                                   b->value.update.message) &&
 975                        zero_hash_eq(a->value.update.old_hash,
 976                                     b->value.update.old_hash, hash_size) &&
 977                        zero_hash_eq(a->value.update.new_hash,
 978                                     b->value.update.new_hash, hash_size);
 979         }
 980
 981         abort();
 982 }
 983
 984 static int reftable_log_record_is_deletion_void(const void *p)
 985 {
 986         return reftable_log_record_is_deletion(
 987                 (const struct reftable_log_record *)p);
 988 }
 989
 990 static void reftable_log_record_print_void(const void *rec, int hash_size)
 991 {
 992         reftable_log_record_print_sz((struct reftable_log_record*)rec, hash_size);
 993 }
 994
 995 static struct reftable_record_vtable reftable_log_record_vtable = {
 996         .key = &reftable_log_record_key,
 997         .type = BLOCK_TYPE_LOG,
 998         .copy_from = &reftable_log_record_copy_from,
 999         .val_type = &reftable_log_record_val_type,
1000         .encode = &reftable_log_record_encode,
1001         .decode = &reftable_log_record_decode,
1002         .release = &reftable_log_record_release_void,
1003         .is_deletion = &reftable_log_record_is_deletion_void,
1004         .equal = &reftable_log_record_equal_void,
1005         .print = &reftable_log_record_print_void,
1006 };
1007
1008 static void reftable_index_record_key(const void *r, struct strbuf *dest)
1009 {
1010         const struct reftable_index_record *rec = r;
1011         strbuf_reset(dest);
1012         strbuf_addbuf(dest, &rec->last_key);
1013 }
1014
1015 static void reftable_index_record_copy_from(void *rec, const void *src_rec,
1016                                             int hash_size)
1017 {
1018         struct reftable_index_record *dst = rec;
1019         const struct reftable_index_record *src = src_rec;
1020
1021         strbuf_reset(&dst->last_key);
1022         strbuf_addbuf(&dst->last_key, &src->last_key);
1023         dst->offset = src->offset;
1024 }
1025
1026 static void reftable_index_record_release(void *rec)
1027 {
1028         struct reftable_index_record *idx = rec;
1029         strbuf_release(&idx->last_key);
1030 }
1031
1032 static uint8_t reftable_index_record_val_type(const void *rec)
1033 {
1034         return 0;
1035 }
1036
1037 static int reftable_index_record_encode(const void *rec, struct string_view out,
1038                                         int hash_size)
1039 {
1040         const struct reftable_index_record *r =
1041                 (const struct reftable_index_record *)rec;
1042         struct string_view start = out;
1043
1044         int n = put_var_int(&out, r->offset);
1045         if (n < 0)
1046                 return n;
1047
1048         string_view_consume(&out, n);
1049
1050         return start.len - out.len;
1051 }
1052
1053 static int reftable_index_record_decode(void *rec, struct strbuf key,
1054                                         uint8_t val_type, struct string_view in,
1055                                         int hash_size)
1056 {
1057         struct string_view start = in;
1058         struct reftable_index_record *r = rec;
1059         int n = 0;
1060
1061         strbuf_reset(&r->last_key);
1062         strbuf_addbuf(&r->last_key, &key);
1063
1064         n = get_var_int(&r->offset, &in);
1065         if (n < 0)
1066                 return n;
1067
1068         string_view_consume(&in, n);
1069         return start.len - in.len;
1070 }
1071
1072 static int reftable_index_record_equal(const void *a, const void *b, int hash_size)
1073 {
1074         struct reftable_index_record *ia = (struct reftable_index_record *) a;
1075         struct reftable_index_record *ib = (struct reftable_index_record *) b;
1076
1077         return ia->offset == ib->offset && !strbuf_cmp(&ia->last_key, &ib->last_key);
1078 }
1079
1080 static void reftable_index_record_print(const void *rec, int hash_size)
1081 {
1082         const struct reftable_index_record *idx = rec;
1083         /* TODO: escape null chars? */
1084         printf("\"%s\" %" PRIu64 "\n", idx->last_key.buf, idx->offset);
1085 }
1086
1087 static struct reftable_record_vtable reftable_index_record_vtable = {
1088         .key = &reftable_index_record_key,
1089         .type = BLOCK_TYPE_INDEX,
1090         .copy_from = &reftable_index_record_copy_from,
1091         .val_type = &reftable_index_record_val_type,
1092         .encode = &reftable_index_record_encode,
1093         .decode = &reftable_index_record_decode,
1094         .release = &reftable_index_record_release,
1095         .is_deletion = &not_a_deletion,
1096         .equal = &reftable_index_record_equal,
1097         .print = &reftable_index_record_print,
1098 };
1099
1100 void reftable_record_key(struct reftable_record *rec, struct strbuf *dest)
1101 {
1102         reftable_record_vtable(rec)->key(reftable_record_data(rec), dest);
1103 }
1104
1105 uint8_t reftable_record_type(struct reftable_record *rec)
1106 {
1107         return rec->type;
1108 }
1109
1110 int reftable_record_encode(struct reftable_record *rec, struct string_view dest,
1111                            int hash_size)
1112 {
1113         return reftable_record_vtable(rec)->encode(reftable_record_data(rec),
1114                                                    dest, hash_size);
1115 }
1116
1117 void reftable_record_copy_from(struct reftable_record *rec,
1118                                struct reftable_record *src, int hash_size)
1119 {
1120         assert(src->type == rec->type);
1121
1122         reftable_record_vtable(rec)->copy_from(reftable_record_data(rec),
1123                                                reftable_record_data(src),
1124                                                hash_size);
1125 }
1126
1127 uint8_t reftable_record_val_type(struct reftable_record *rec)
1128 {
1129         return reftable_record_vtable(rec)->val_type(reftable_record_data(rec));
1130 }
1131
1132 int reftable_record_decode(struct reftable_record *rec, struct strbuf key,
1133                            uint8_t extra, struct string_view src, int hash_size)
1134 {
1135         return reftable_record_vtable(rec)->decode(reftable_record_data(rec),
1136                                                    key, extra, src, hash_size);
1137 }
1138
1139 void reftable_record_release(struct reftable_record *rec)
1140 {
1141         reftable_record_vtable(rec)->release(reftable_record_data(rec));
1142 }
1143
1144 int reftable_record_is_deletion(struct reftable_record *rec)
1145 {
1146         return reftable_record_vtable(rec)->is_deletion(
1147                 reftable_record_data(rec));
1148 }
1149
1150 int reftable_record_equal(struct reftable_record *a, struct reftable_record *b, int hash_size)
1151 {
1152         if (a->type != b->type)
1153                 return 0;
1154         return reftable_record_vtable(a)->equal(
1155                 reftable_record_data(a), reftable_record_data(b), hash_size);
1156 }
1157
1158 static int hash_equal(const unsigned char *a, const unsigned char *b, int hash_size)
1159 {
1160         if (a && b)
1161                 return !memcmp(a, b, hash_size);
1162
1163         return a == b;
1164 }
1165
1166 int reftable_ref_record_equal(const struct reftable_ref_record *a,
1167                               const struct reftable_ref_record *b, int hash_size)
1168 {
1169         assert(hash_size > 0);
1170         if (!null_streq(a->refname, b->refname))
1171                 return 0;
1172
1173         if (a->update_index != b->update_index ||
1174             a->value_type != b->value_type)
1175                 return 0;
1176
1177         switch (a->value_type) {
1178         case REFTABLE_REF_SYMREF:
1179                 return !strcmp(a->value.symref, b->value.symref);
1180         case REFTABLE_REF_VAL2:
1181                 return hash_equal(a->value.val2.value, b->value.val2.value,
1182                                   hash_size) &&
1183                        hash_equal(a->value.val2.target_value,
1184                                   b->value.val2.target_value, hash_size);
1185         case REFTABLE_REF_VAL1:
1186                 return hash_equal(a->value.val1, b->value.val1, hash_size);
1187         case REFTABLE_REF_DELETION:
1188                 return 1;
1189         default:
1190                 abort();
1191         }
1192 }
1193
1194 int reftable_ref_record_compare_name(const void *a, const void *b)
1195 {
1196         return strcmp(((struct reftable_ref_record *)a)->refname,
1197                       ((struct reftable_ref_record *)b)->refname);
1198 }
1199
1200 int reftable_ref_record_is_deletion(const struct reftable_ref_record *ref)
1201 {
1202         return ref->value_type == REFTABLE_REF_DELETION;
1203 }
1204
1205 int reftable_log_record_compare_key(const void *a, const void *b)
1206 {
1207         const struct reftable_log_record *la = a;
1208         const struct reftable_log_record *lb = b;
1209
1210         int cmp = strcmp(la->refname, lb->refname);
1211         if (cmp)
1212                 return cmp;
1213         if (la->update_index > lb->update_index)
1214                 return -1;
1215         return (la->update_index < lb->update_index) ? 1 : 0;
1216 }
1217
1218 int reftable_log_record_is_deletion(const struct reftable_log_record *log)
1219 {
1220         return (log->value_type == REFTABLE_LOG_DELETION);
1221 }
1222
1223 void string_view_consume(struct string_view *s, int n)
1224 {
1225         s->buf += n;
1226         s->len -= n;
1227 }
1228
1229 static void *reftable_record_data(struct reftable_record *rec)
1230 {
1231         switch (rec->type) {
1232         case BLOCK_TYPE_REF:
1233                 return &rec->u.ref;
1234         case BLOCK_TYPE_LOG:
1235                 return &rec->u.log;
1236         case BLOCK_TYPE_INDEX:
1237                 return &rec->u.idx;
1238         case BLOCK_TYPE_OBJ:
1239                 return &rec->u.obj;
1240         }
1241         abort();
1242 }
1243
1244 static struct reftable_record_vtable *
1245 reftable_record_vtable(struct reftable_record *rec)
1246 {
1247         switch (rec->type) {
1248         case BLOCK_TYPE_REF:
1249                 return &reftable_ref_record_vtable;
1250         case BLOCK_TYPE_LOG:
1251                 return &reftable_log_record_vtable;
1252         case BLOCK_TYPE_INDEX:
1253                 return &reftable_index_record_vtable;
1254         case BLOCK_TYPE_OBJ:
1255                 return &reftable_obj_record_vtable;
1256         }
1257         abort();
1258 }
1259
1260 struct reftable_record reftable_new_record(uint8_t typ)
1261 {
1262         struct reftable_record clean = {
1263                 .type = typ,
1264         };
1265
1266         /* the following is involved, but the naive solution (just return
1267          * `clean` as is, except for BLOCK_TYPE_INDEX), returns a garbage
1268          * clean.u.obj.offsets pointer on Windows VS CI.  Go figure.
1269          */
1270         switch (typ) {
1271         case BLOCK_TYPE_OBJ:
1272         {
1273                 struct reftable_obj_record obj = { 0 };
1274                 clean.u.obj = obj;
1275                 break;
1276         }
1277         case BLOCK_TYPE_INDEX:
1278         {
1279                 struct reftable_index_record idx = {
1280                         .last_key = STRBUF_INIT,
1281                 };
1282                 clean.u.idx = idx;
1283                 break;
1284         }
1285         case BLOCK_TYPE_REF:
1286         {
1287                 struct reftable_ref_record ref = { 0 };
1288                 clean.u.ref = ref;
1289                 break;
1290         }
1291         case BLOCK_TYPE_LOG:
1292         {
1293                 struct reftable_log_record log = { 0 };
1294                 clean.u.log = log;
1295                 break;
1296         }
1297         }
1298         return clean;
1299 }
1300
1301 void reftable_record_print(struct reftable_record *rec, int hash_size)
1302 {
1303         printf("'%c': ", rec->type);
1304         reftable_record_vtable(rec)->print(reftable_record_data(rec), hash_size);
1305 }