diff options
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | reftable/block.c | 437 | ||||
| -rw-r--r-- | reftable/block.h | 127 | ||||
| -rw-r--r-- | reftable/block_test.c | 120 | ||||
| -rw-r--r-- | t/helper/test-reftable.c | 1 |
5 files changed, 687 insertions, 0 deletions
@@ -2458,10 +2458,12 @@ xdiff-objs: $(XDIFF_OBJS) REFTABLE_OBJS += reftable/basics.o REFTABLE_OBJS += reftable/error.o +REFTABLE_OBJS += reftable/block.o REFTABLE_OBJS += reftable/blocksource.o REFTABLE_OBJS += reftable/publicbasics.o REFTABLE_OBJS += reftable/record.o +REFTABLE_TEST_OBJS += reftable/block_test.o REFTABLE_TEST_OBJS += reftable/record_test.o REFTABLE_TEST_OBJS += reftable/test_framework.o REFTABLE_TEST_OBJS += reftable/basics_test.o diff --git a/reftable/block.c b/reftable/block.c new file mode 100644 index 0000000000..855e3f5c94 --- /dev/null +++ b/reftable/block.c @@ -0,0 +1,437 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#include "block.h" + +#include "blocksource.h" +#include "constants.h" +#include "record.h" +#include "reftable-error.h" +#include "system.h" +#include <zlib.h> + +int header_size(int version) +{ + switch (version) { + case 1: + return 24; + case 2: + return 28; + } + abort(); +} + +int footer_size(int version) +{ + switch (version) { + case 1: + return 68; + case 2: + return 72; + } + abort(); +} + +static int block_writer_register_restart(struct block_writer *w, int n, + int is_restart, struct strbuf *key) +{ + int rlen = w->restart_len; + if (rlen >= MAX_RESTARTS) { + is_restart = 0; + } + + if (is_restart) { + rlen++; + } + if (2 + 3 * rlen + n > w->block_size - w->next) + return -1; + if (is_restart) { + if (w->restart_len == w->restart_cap) { + w->restart_cap = w->restart_cap * 2 + 1; + w->restarts = reftable_realloc( + w->restarts, sizeof(uint32_t) * w->restart_cap); + } + + w->restarts[w->restart_len++] = w->next; + } + + w->next += n; + + strbuf_reset(&w->last_key); + strbuf_addbuf(&w->last_key, key); + w->entries++; + return 0; +} + +void block_writer_init(struct block_writer *bw, uint8_t typ, uint8_t *buf, + uint32_t block_size, uint32_t header_off, int hash_size) +{ + bw->buf = buf; + bw->hash_size = hash_size; + bw->block_size = block_size; + bw->header_off = header_off; + bw->buf[header_off] = typ; + bw->next = header_off + 4; + bw->restart_interval = 16; + bw->entries = 0; + bw->restart_len = 0; + bw->last_key.len = 0; +} + +uint8_t block_writer_type(struct block_writer *bw) +{ + return bw->buf[bw->header_off]; +} + +/* adds the reftable_record to the block. Returns -1 if it does not fit, 0 on + success */ +int block_writer_add(struct block_writer *w, struct reftable_record *rec) +{ + struct strbuf empty = STRBUF_INIT; + struct strbuf last = + w->entries % w->restart_interval == 0 ? empty : w->last_key; + struct string_view out = { + .buf = w->buf + w->next, + .len = w->block_size - w->next, + }; + + struct string_view start = out; + + int is_restart = 0; + struct strbuf key = STRBUF_INIT; + int n = 0; + + reftable_record_key(rec, &key); + n = reftable_encode_key(&is_restart, out, last, key, + reftable_record_val_type(rec)); + if (n < 0) + goto done; + string_view_consume(&out, n); + + n = reftable_record_encode(rec, out, w->hash_size); + if (n < 0) + goto done; + string_view_consume(&out, n); + + if (block_writer_register_restart(w, start.len - out.len, is_restart, + &key) < 0) + goto done; + + strbuf_release(&key); + return 0; + +done: + strbuf_release(&key); + return -1; +} + +int block_writer_finish(struct block_writer *w) +{ + int i; + for (i = 0; i < w->restart_len; i++) { + put_be24(w->buf + w->next, w->restarts[i]); + w->next += 3; + } + + put_be16(w->buf + w->next, w->restart_len); + w->next += 2; + put_be24(w->buf + 1 + w->header_off, w->next); + + if (block_writer_type(w) == BLOCK_TYPE_LOG) { + int block_header_skip = 4 + w->header_off; + uLongf src_len = w->next - block_header_skip; + uLongf dest_cap = src_len * 1.001 + 12; + + uint8_t *compressed = reftable_malloc(dest_cap); + while (1) { + uLongf out_dest_len = dest_cap; + int zresult = compress2(compressed, &out_dest_len, + w->buf + block_header_skip, + src_len, 9); + if (zresult == Z_BUF_ERROR && dest_cap < LONG_MAX) { + dest_cap *= 2; + compressed = + reftable_realloc(compressed, dest_cap); + if (compressed) + continue; + } + + if (Z_OK != zresult) { + reftable_free(compressed); + return REFTABLE_ZLIB_ERROR; + } + + memcpy(w->buf + block_header_skip, compressed, + out_dest_len); + w->next = out_dest_len + block_header_skip; + reftable_free(compressed); + break; + } + } + return w->next; +} + +uint8_t block_reader_type(struct block_reader *r) +{ + return r->block.data[r->header_off]; +} + +int block_reader_init(struct block_reader *br, struct reftable_block *block, + uint32_t header_off, uint32_t table_block_size, + int hash_size) +{ + uint32_t full_block_size = table_block_size; + uint8_t typ = block->data[header_off]; + uint32_t sz = get_be24(block->data + header_off + 1); + + uint16_t restart_count = 0; + uint32_t restart_start = 0; + uint8_t *restart_bytes = NULL; + + if (!reftable_is_block_type(typ)) + return REFTABLE_FORMAT_ERROR; + + if (typ == BLOCK_TYPE_LOG) { + int block_header_skip = 4 + header_off; + uLongf dst_len = sz - block_header_skip; /* total size of dest + buffer. */ + uLongf src_len = block->len - block_header_skip; + /* Log blocks specify the *uncompressed* size in their header. + */ + uint8_t *uncompressed = reftable_malloc(sz); + + /* Copy over the block header verbatim. It's not compressed. */ + memcpy(uncompressed, block->data, block_header_skip); + + /* Uncompress */ + if (Z_OK != + uncompress2(uncompressed + block_header_skip, &dst_len, + block->data + block_header_skip, &src_len)) { + reftable_free(uncompressed); + return REFTABLE_ZLIB_ERROR; + } + + if (dst_len + block_header_skip != sz) + return REFTABLE_FORMAT_ERROR; + + /* We're done with the input data. */ + reftable_block_done(block); + block->data = uncompressed; + block->len = sz; + block->source = malloc_block_source(); + full_block_size = src_len + block_header_skip; + } else if (full_block_size == 0) { + full_block_size = sz; + } else if (sz < full_block_size && sz < block->len && + block->data[sz] != 0) { + /* If the block is smaller than the full block size, it is + padded (data followed by '\0') or the next block is + unaligned. */ + full_block_size = sz; + } + + restart_count = get_be16(block->data + sz - 2); + restart_start = sz - 2 - 3 * restart_count; + restart_bytes = block->data + restart_start; + + /* transfer ownership. */ + br->block = *block; + block->data = NULL; + block->len = 0; + + br->hash_size = hash_size; + br->block_len = restart_start; + br->full_block_size = full_block_size; + br->header_off = header_off; + br->restart_count = restart_count; + br->restart_bytes = restart_bytes; + + return 0; +} + +static uint32_t block_reader_restart_offset(struct block_reader *br, int i) +{ + return get_be24(br->restart_bytes + 3 * i); +} + +void block_reader_start(struct block_reader *br, struct block_iter *it) +{ + it->br = br; + strbuf_reset(&it->last_key); + it->next_off = br->header_off + 4; +} + +struct restart_find_args { + int error; + struct strbuf key; + struct block_reader *r; +}; + +static int restart_key_less(size_t idx, void *args) +{ + struct restart_find_args *a = args; + uint32_t off = block_reader_restart_offset(a->r, idx); + struct string_view in = { + .buf = a->r->block.data + off, + .len = a->r->block_len - off, + }; + + /* the restart key is verbatim in the block, so this could avoid the + alloc for decoding the key */ + struct strbuf rkey = STRBUF_INIT; + struct strbuf last_key = STRBUF_INIT; + uint8_t unused_extra; + int n = reftable_decode_key(&rkey, &unused_extra, last_key, in); + int result; + if (n < 0) { + a->error = 1; + return -1; + } + + result = strbuf_cmp(&a->key, &rkey); + strbuf_release(&rkey); + return result; +} + +void block_iter_copy_from(struct block_iter *dest, struct block_iter *src) +{ + dest->br = src->br; + dest->next_off = src->next_off; + strbuf_reset(&dest->last_key); + strbuf_addbuf(&dest->last_key, &src->last_key); +} + +int block_iter_next(struct block_iter *it, struct reftable_record *rec) +{ + struct string_view in = { + .buf = it->br->block.data + it->next_off, + .len = it->br->block_len - it->next_off, + }; + struct string_view start = in; + struct strbuf key = STRBUF_INIT; + uint8_t extra = 0; + int n = 0; + + if (it->next_off >= it->br->block_len) + return 1; + + n = reftable_decode_key(&key, &extra, it->last_key, in); + if (n < 0) + return -1; + + string_view_consume(&in, n); + n = reftable_record_decode(rec, key, extra, in, it->br->hash_size); + if (n < 0) + return -1; + string_view_consume(&in, n); + + strbuf_reset(&it->last_key); + strbuf_addbuf(&it->last_key, &key); + it->next_off += start.len - in.len; + strbuf_release(&key); + return 0; +} + +int block_reader_first_key(struct block_reader *br, struct strbuf *key) +{ + struct strbuf empty = STRBUF_INIT; + int off = br->header_off + 4; + struct string_view in = { + .buf = br->block.data + off, + .len = br->block_len - off, + }; + + uint8_t extra = 0; + int n = reftable_decode_key(key, &extra, empty, in); + if (n < 0) + return n; + + return 0; +} + +int block_iter_seek(struct block_iter *it, struct strbuf *want) +{ + return block_reader_seek(it->br, it, want); +} + +void block_iter_close(struct block_iter *it) +{ + strbuf_release(&it->last_key); +} + +int block_reader_seek(struct block_reader *br, struct block_iter *it, + struct strbuf *want) +{ + struct restart_find_args args = { + .key = *want, + .r = br, + }; + struct reftable_record rec = reftable_new_record(block_reader_type(br)); + struct strbuf key = STRBUF_INIT; + int err = 0; + struct block_iter next = { + .last_key = STRBUF_INIT, + }; + + int i = binsearch(br->restart_count, &restart_key_less, &args); + if (args.error) { + err = REFTABLE_FORMAT_ERROR; + goto done; + } + + it->br = br; + if (i > 0) { + i--; + it->next_off = block_reader_restart_offset(br, i); + } else { + it->next_off = br->header_off + 4; + } + + /* We're looking for the last entry less/equal than the wanted key, so + we have to go one entry too far and then back up. + */ + while (1) { + block_iter_copy_from(&next, it); + err = block_iter_next(&next, &rec); + if (err < 0) + goto done; + + reftable_record_key(&rec, &key); + if (err > 0 || strbuf_cmp(&key, want) >= 0) { + err = 0; + goto done; + } + + block_iter_copy_from(it, &next); + } + +done: + strbuf_release(&key); + strbuf_release(&next.last_key); + reftable_record_destroy(&rec); + + return err; +} + +void block_writer_release(struct block_writer *bw) +{ + FREE_AND_NULL(bw->restarts); + strbuf_release(&bw->last_key); + /* the block is not owned. */ +} + +void reftable_block_done(struct reftable_block *blockp) +{ + struct reftable_block_source source = blockp->source; + if (blockp && source.ops) + source.ops->return_block(source.arg, blockp); + blockp->data = NULL; + blockp->len = 0; + blockp->source.ops = NULL; + blockp->source.arg = NULL; +} diff --git a/reftable/block.h b/reftable/block.h new file mode 100644 index 0000000000..e207706a64 --- /dev/null +++ b/reftable/block.h @@ -0,0 +1,127 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#ifndef BLOCK_H +#define BLOCK_H + +#include "basics.h" +#include "record.h" +#include "reftable-blocksource.h" + +/* + * Writes reftable blocks. The block_writer is reused across blocks to minimize + * allocation overhead. + */ +struct block_writer { + uint8_t *buf; + uint32_t block_size; + + /* Offset ofof the global header. Nonzero in the first block only. */ + uint32_t header_off; + + /* How often to restart keys. */ + int restart_interval; + int hash_size; + + /* Offset of next uint8_t to write. */ + uint32_t next; + uint32_t *restarts; + uint32_t restart_len; + uint32_t restart_cap; + + struct strbuf last_key; + int entries; +}; + +/* + * initializes the blockwriter to write `typ` entries, using `buf` as temporary + * storage. `buf` is not owned by the block_writer. */ +void block_writer_init(struct block_writer *bw, uint8_t typ, uint8_t *buf, + uint32_t block_size, uint32_t header_off, int hash_size); + +/* returns the block type (eg. 'r' for ref records. */ +uint8_t block_writer_type(struct block_writer *bw); + +/* appends the record, or -1 if it doesn't fit. */ +int block_writer_add(struct block_writer *w, struct reftable_record *rec); + +/* appends the key restarts, and compress the block if necessary. */ +int block_writer_finish(struct block_writer *w); + +/* clears out internally allocated block_writer members. */ +void block_writer_release(struct block_writer *bw); + +/* Read a block. */ +struct block_reader { + /* offset of the block header; nonzero for the first block in a + * reftable. */ + uint32_t header_off; + + /* the memory block */ + struct reftable_block block; + int hash_size; + + /* size of the data, excluding restart data. */ + uint32_t block_len; + uint8_t *restart_bytes; + uint16_t restart_count; + + /* size of the data in the file. For log blocks, this is the compressed + * size. */ + uint32_t full_block_size; +}; + +/* Iterate over entries in a block */ +struct block_iter { + /* offset within the block of the next entry to read. */ + uint32_t next_off; + struct block_reader *br; + + /* key for last entry we read. */ + struct strbuf last_key; +}; + +/* initializes a block reader. */ +int block_reader_init(struct block_reader *br, struct reftable_block *bl, + uint32_t header_off, uint32_t table_block_size, + int hash_size); + +/* Position `it` at start of the block */ +void block_reader_start(struct block_reader *br, struct block_iter *it); + +/* Position `it` to the `want` key in the block */ +int block_reader_seek(struct block_reader *br, struct block_iter *it, + struct strbuf *want); + +/* Returns the block type (eg. 'r' for refs) */ +uint8_t block_reader_type(struct block_reader *r); + +/* Decodes the first key in the block */ +int block_reader_first_key(struct block_reader *br, struct strbuf *key); + +void block_iter_copy_from(struct block_iter *dest, struct block_iter *src); + +/* return < 0 for error, 0 for OK, > 0 for EOF. */ +int block_iter_next(struct block_iter *it, struct reftable_record *rec); + +/* Seek to `want` with in the block pointed to by `it` */ +int block_iter_seek(struct block_iter *it, struct strbuf *want); + +/* deallocate memory for `it`. The block reader and its block is left intact. */ +void block_iter_close(struct block_iter *it); + +/* size of file header, depending on format version */ +int header_size(int version); + +/* size of file footer, depending on format version */ +int footer_size(int version); + +/* returns a block to its source. */ +void reftable_block_done(struct reftable_block *ret); + +#endif diff --git a/reftable/block_test.c b/reftable/block_test.c new file mode 100644 index 0000000000..4b3ea262dc --- /dev/null +++ b/reftable/block_test.c @@ -0,0 +1,120 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#include "block.h" + +#include "system.h" +#include "blocksource.h" +#include "basics.h" +#include "constants.h" +#include "record.h" +#include "test_framework.h" +#include "reftable-tests.h" + +static void test_block_read_write(void) +{ + const int header_off = 21; /* random */ + char *names[30]; + const int N = ARRAY_SIZE(names); + const int block_size = 1024; + struct reftable_block block = { NULL }; + struct block_writer bw = { + .last_key = STRBUF_INIT, + }; + struct reftable_ref_record ref = { NULL }; + struct reftable_record rec = { NULL }; + int i = 0; + int n; + struct block_reader br = { 0 }; + struct block_iter it = { .last_key = STRBUF_INIT }; + int j = 0; + struct strbuf want = STRBUF_INIT; + + block.data = reftable_calloc(block_size); + block.len = block_size; + block.source = malloc_block_source(); + block_writer_init(&bw, BLOCK_TYPE_REF, block.data, block_size, + header_off, hash_size(GIT_SHA1_FORMAT_ID)); + reftable_record_from_ref(&rec, &ref); + + for (i = 0; i < N; i++) { + char name[100]; + uint8_t hash[GIT_SHA1_RAWSZ]; + snprintf(name, sizeof(name), "branch%02d", i); + memset(hash, i, sizeof(hash)); + + ref.refname = name; + ref.value_type = REFTABLE_REF_VAL1; + ref.value.val1 = hash; + + names[i] = xstrdup(name); + n = block_writer_add(&bw, &rec); + ref.refname = NULL; + ref.value_type = REFTABLE_REF_DELETION; + EXPECT(n == 0); + } + + n = block_writer_finish(&bw); + EXPECT(n > 0); + + block_writer_release(&bw); + + block_reader_init(&br, &block, header_off, block_size, GIT_SHA1_RAWSZ); + + block_reader_start(&br, &it); + + while (1) { + int r = block_iter_next(&it, &rec); + EXPECT(r >= 0); + if (r > 0) { + break; + } + EXPECT_STREQ(names[j], ref.refname); + j++; + } + + reftable_record_release(&rec); + block_iter_close(&it); + + for (i = 0; i < N; i++) { + struct block_iter it = { .last_key = STRBUF_INIT }; + strbuf_reset(&want); + strbuf_addstr(&want, names[i]); + + n = block_reader_seek(&br, &it, &want); + EXPECT(n == 0); + + n = block_iter_next(&it, &rec); + EXPECT(n == 0); + + EXPECT_STREQ(names[i], ref.refname); + + want.len--; + n = block_reader_seek(&br, &it, &want); + EXPECT(n == 0); + + n = block_iter_next(&it, &rec); + EXPECT(n == 0); + EXPECT_STREQ(names[10 * (i / 10)], ref.refname); + + block_iter_close(&it); + } + + reftable_record_release(&rec); + reftable_block_done(&br.block); + strbuf_release(&want); + for (i = 0; i < N; i++) { + reftable_free(names[i]); + } +} + +int block_test_main(int argc, const char *argv[]) +{ + RUN_TEST(test_block_read_write); + return 0; +} diff --git a/t/helper/test-reftable.c b/t/helper/test-reftable.c index 09d4b83ef9..c9deeaf08c 100644 --- a/t/helper/test-reftable.c +++ b/t/helper/test-reftable.c @@ -4,6 +4,7 @@ int cmd__reftable(int argc, const char **argv) { basics_test_main(argc, argv); + block_test_main(argc, argv); record_test_main(argc, argv); return 0; } |