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reftable: read reftable files
This supports reading a single reftable file. The commit introduces an abstract iterator type, which captures the usecases both of reading individual refs, and iterating over a segment of the ref namespace. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Han-Wen Nienhuys
Junio C Hamano
parent
17df8dbeba
commit
46bc0e731a
2
Makefile
2
Makefile
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@ -2460,7 +2460,9 @@ REFTABLE_OBJS += reftable/basics.o
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REFTABLE_OBJS += reftable/error.o
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REFTABLE_OBJS += reftable/block.o
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REFTABLE_OBJS += reftable/blocksource.o
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REFTABLE_OBJS += reftable/iter.o
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REFTABLE_OBJS += reftable/publicbasics.o
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REFTABLE_OBJS += reftable/reader.o
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REFTABLE_OBJS += reftable/record.o
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REFTABLE_OBJS += reftable/refname.o
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REFTABLE_OBJS += reftable/generic.o
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@ -0,0 +1,194 @@
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/*
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Copyright 2020 Google LLC
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file or at
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https://developers.google.com/open-source/licenses/bsd
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*/
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#include "iter.h"
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#include "system.h"
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#include "block.h"
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#include "generic.h"
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#include "constants.h"
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#include "reader.h"
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#include "reftable-error.h"
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int iterator_is_null(struct reftable_iterator *it)
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{
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return !it->ops;
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}
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static void filtering_ref_iterator_close(void *iter_arg)
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{
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struct filtering_ref_iterator *fri = iter_arg;
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strbuf_release(&fri->oid);
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reftable_iterator_destroy(&fri->it);
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}
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static int filtering_ref_iterator_next(void *iter_arg,
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struct reftable_record *rec)
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{
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struct filtering_ref_iterator *fri = iter_arg;
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struct reftable_ref_record *ref = rec->data;
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int err = 0;
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while (1) {
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err = reftable_iterator_next_ref(&fri->it, ref);
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if (err != 0) {
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break;
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}
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if (fri->double_check) {
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struct reftable_iterator it = { NULL };
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err = reftable_table_seek_ref(&fri->tab, &it,
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ref->refname);
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if (err == 0) {
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err = reftable_iterator_next_ref(&it, ref);
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}
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reftable_iterator_destroy(&it);
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if (err < 0) {
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break;
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}
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if (err > 0) {
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continue;
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}
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}
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if (ref->value_type == REFTABLE_REF_VAL2 &&
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(!memcmp(fri->oid.buf, ref->value.val2.target_value,
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fri->oid.len) ||
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!memcmp(fri->oid.buf, ref->value.val2.value,
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fri->oid.len)))
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return 0;
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if (ref->value_type == REFTABLE_REF_VAL1 &&
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!memcmp(fri->oid.buf, ref->value.val1, fri->oid.len)) {
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return 0;
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}
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}
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reftable_ref_record_release(ref);
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return err;
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}
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static struct reftable_iterator_vtable filtering_ref_iterator_vtable = {
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.next = &filtering_ref_iterator_next,
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.close = &filtering_ref_iterator_close,
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};
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void iterator_from_filtering_ref_iterator(struct reftable_iterator *it,
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struct filtering_ref_iterator *fri)
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{
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assert(!it->ops);
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it->iter_arg = fri;
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it->ops = &filtering_ref_iterator_vtable;
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}
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static void indexed_table_ref_iter_close(void *p)
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{
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struct indexed_table_ref_iter *it = p;
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block_iter_close(&it->cur);
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reftable_block_done(&it->block_reader.block);
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reftable_free(it->offsets);
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strbuf_release(&it->oid);
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}
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static int indexed_table_ref_iter_next_block(struct indexed_table_ref_iter *it)
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{
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uint64_t off;
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int err = 0;
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if (it->offset_idx == it->offset_len) {
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it->is_finished = 1;
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return 1;
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}
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reftable_block_done(&it->block_reader.block);
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off = it->offsets[it->offset_idx++];
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err = reader_init_block_reader(it->r, &it->block_reader, off,
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BLOCK_TYPE_REF);
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if (err < 0) {
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return err;
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}
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if (err > 0) {
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/* indexed block does not exist. */
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return REFTABLE_FORMAT_ERROR;
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}
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block_reader_start(&it->block_reader, &it->cur);
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return 0;
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}
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static int indexed_table_ref_iter_next(void *p, struct reftable_record *rec)
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{
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struct indexed_table_ref_iter *it = p;
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struct reftable_ref_record *ref = rec->data;
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while (1) {
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int err = block_iter_next(&it->cur, rec);
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if (err < 0) {
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return err;
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}
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if (err > 0) {
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err = indexed_table_ref_iter_next_block(it);
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if (err < 0) {
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return err;
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}
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if (it->is_finished) {
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return 1;
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}
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continue;
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}
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/* BUG */
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if (!memcmp(it->oid.buf, ref->value.val2.target_value,
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it->oid.len) ||
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!memcmp(it->oid.buf, ref->value.val2.value, it->oid.len)) {
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return 0;
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}
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}
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}
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int new_indexed_table_ref_iter(struct indexed_table_ref_iter **dest,
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struct reftable_reader *r, uint8_t *oid,
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int oid_len, uint64_t *offsets, int offset_len)
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{
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struct indexed_table_ref_iter empty = INDEXED_TABLE_REF_ITER_INIT;
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struct indexed_table_ref_iter *itr =
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reftable_calloc(sizeof(struct indexed_table_ref_iter));
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int err = 0;
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*itr = empty;
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itr->r = r;
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strbuf_add(&itr->oid, oid, oid_len);
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itr->offsets = offsets;
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itr->offset_len = offset_len;
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err = indexed_table_ref_iter_next_block(itr);
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if (err < 0) {
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reftable_free(itr);
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} else {
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*dest = itr;
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}
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return err;
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}
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static struct reftable_iterator_vtable indexed_table_ref_iter_vtable = {
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.next = &indexed_table_ref_iter_next,
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.close = &indexed_table_ref_iter_close,
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};
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void iterator_from_indexed_table_ref_iter(struct reftable_iterator *it,
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struct indexed_table_ref_iter *itr)
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{
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assert(!it->ops);
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it->iter_arg = itr;
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it->ops = &indexed_table_ref_iter_vtable;
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}
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@ -0,0 +1,69 @@
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/*
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Copyright 2020 Google LLC
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file or at
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https://developers.google.com/open-source/licenses/bsd
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*/
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#ifndef ITER_H
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#define ITER_H
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#include "system.h"
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#include "block.h"
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#include "record.h"
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#include "reftable-iterator.h"
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#include "reftable-generic.h"
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/* Returns true for a zeroed out iterator, such as the one returned from
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* iterator_destroy. */
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int iterator_is_null(struct reftable_iterator *it);
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/* iterator that produces only ref records that point to `oid` */
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struct filtering_ref_iterator {
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int double_check;
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struct reftable_table tab;
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struct strbuf oid;
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struct reftable_iterator it;
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};
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#define FILTERING_REF_ITERATOR_INIT \
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{ \
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.oid = STRBUF_INIT \
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}
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void iterator_from_filtering_ref_iterator(struct reftable_iterator *,
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struct filtering_ref_iterator *);
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/* iterator that produces only ref records that point to `oid`,
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* but using the object index.
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*/
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struct indexed_table_ref_iter {
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struct reftable_reader *r;
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struct strbuf oid;
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/* mutable */
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uint64_t *offsets;
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/* Points to the next offset to read. */
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int offset_idx;
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int offset_len;
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struct block_reader block_reader;
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struct block_iter cur;
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int is_finished;
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};
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#define INDEXED_TABLE_REF_ITER_INIT \
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{ \
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.cur = { .last_key = STRBUF_INIT }, .oid = STRBUF_INIT, \
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}
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void iterator_from_indexed_table_ref_iter(struct reftable_iterator *it,
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struct indexed_table_ref_iter *itr);
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/* Takes ownership of `offsets` */
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int new_indexed_table_ref_iter(struct indexed_table_ref_iter **dest,
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struct reftable_reader *r, uint8_t *oid,
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int oid_len, uint64_t *offsets, int offset_len);
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#endif
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@ -0,0 +1,801 @@
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/*
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Copyright 2020 Google LLC
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file or at
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https://developers.google.com/open-source/licenses/bsd
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*/
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#include "reader.h"
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#include "system.h"
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#include "block.h"
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#include "constants.h"
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#include "generic.h"
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#include "iter.h"
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#include "record.h"
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#include "reftable-error.h"
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#include "reftable-generic.h"
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#include "tree.h"
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uint64_t block_source_size(struct reftable_block_source *source)
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{
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return source->ops->size(source->arg);
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}
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int block_source_read_block(struct reftable_block_source *source,
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struct reftable_block *dest, uint64_t off,
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uint32_t size)
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{
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int result = source->ops->read_block(source->arg, dest, off, size);
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dest->source = *source;
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return result;
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}
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void block_source_close(struct reftable_block_source *source)
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{
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if (!source->ops) {
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return;
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}
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source->ops->close(source->arg);
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source->ops = NULL;
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}
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static struct reftable_reader_offsets *
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reader_offsets_for(struct reftable_reader *r, uint8_t typ)
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{
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switch (typ) {
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case BLOCK_TYPE_REF:
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return &r->ref_offsets;
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case BLOCK_TYPE_LOG:
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return &r->log_offsets;
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case BLOCK_TYPE_OBJ:
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return &r->obj_offsets;
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}
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abort();
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}
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static int reader_get_block(struct reftable_reader *r,
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struct reftable_block *dest, uint64_t off,
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uint32_t sz)
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{
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if (off >= r->size)
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return 0;
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if (off + sz > r->size) {
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sz = r->size - off;
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}
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return block_source_read_block(&r->source, dest, off, sz);
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}
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uint32_t reftable_reader_hash_id(struct reftable_reader *r)
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{
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return r->hash_id;
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}
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const char *reader_name(struct reftable_reader *r)
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{
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return r->name;
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}
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static int parse_footer(struct reftable_reader *r, uint8_t *footer,
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uint8_t *header)
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{
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uint8_t *f = footer;
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uint8_t first_block_typ;
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int err = 0;
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uint32_t computed_crc;
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uint32_t file_crc;
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if (memcmp(f, "REFT", 4)) {
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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f += 4;
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if (memcmp(footer, header, header_size(r->version))) {
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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f++;
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r->block_size = get_be24(f);
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f += 3;
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r->min_update_index = get_be64(f);
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f += 8;
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r->max_update_index = get_be64(f);
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f += 8;
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if (r->version == 1) {
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r->hash_id = GIT_SHA1_FORMAT_ID;
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} else {
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r->hash_id = get_be32(f);
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switch (r->hash_id) {
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case GIT_SHA1_FORMAT_ID:
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break;
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case GIT_SHA256_FORMAT_ID:
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break;
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default:
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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f += 4;
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}
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r->ref_offsets.index_offset = get_be64(f);
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f += 8;
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r->obj_offsets.offset = get_be64(f);
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f += 8;
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r->object_id_len = r->obj_offsets.offset & ((1 << 5) - 1);
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r->obj_offsets.offset >>= 5;
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r->obj_offsets.index_offset = get_be64(f);
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f += 8;
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r->log_offsets.offset = get_be64(f);
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f += 8;
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r->log_offsets.index_offset = get_be64(f);
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f += 8;
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computed_crc = crc32(0, footer, f - footer);
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file_crc = get_be32(f);
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f += 4;
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if (computed_crc != file_crc) {
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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first_block_typ = header[header_size(r->version)];
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r->ref_offsets.is_present = (first_block_typ == BLOCK_TYPE_REF);
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r->ref_offsets.offset = 0;
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r->log_offsets.is_present = (first_block_typ == BLOCK_TYPE_LOG ||
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r->log_offsets.offset > 0);
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r->obj_offsets.is_present = r->obj_offsets.offset > 0;
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err = 0;
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done:
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return err;
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}
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int init_reader(struct reftable_reader *r, struct reftable_block_source *source,
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const char *name)
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{
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struct reftable_block footer = { NULL };
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struct reftable_block header = { NULL };
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int err = 0;
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uint64_t file_size = block_source_size(source);
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/* Need +1 to read type of first block. */
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uint32_t read_size = header_size(2) + 1; /* read v2 because it's larger. */
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memset(r, 0, sizeof(struct reftable_reader));
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if (read_size > file_size) {
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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err = block_source_read_block(source, &header, 0, read_size);
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if (err != read_size) {
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err = REFTABLE_IO_ERROR;
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goto done;
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}
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if (memcmp(header.data, "REFT", 4)) {
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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r->version = header.data[4];
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if (r->version != 1 && r->version != 2) {
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err = REFTABLE_FORMAT_ERROR;
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goto done;
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}
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r->size = file_size - footer_size(r->version);
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r->source = *source;
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r->name = xstrdup(name);
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r->hash_id = 0;
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err = block_source_read_block(source, &footer, r->size,
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footer_size(r->version));
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if (err != footer_size(r->version)) {
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err = REFTABLE_IO_ERROR;
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goto done;
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}
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err = parse_footer(r, footer.data, header.data);
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done:
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reftable_block_done(&footer);
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reftable_block_done(&header);
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return err;
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}
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struct table_iter {
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struct reftable_reader *r;
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uint8_t typ;
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uint64_t block_off;
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struct block_iter bi;
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int is_finished;
|
||||
};
|
||||
#define TABLE_ITER_INIT \
|
||||
{ \
|
||||
.bi = {.last_key = STRBUF_INIT } \
|
||||
}
|
||||
|
||||
static void table_iter_copy_from(struct table_iter *dest,
|
||||
struct table_iter *src)
|
||||
{
|
||||
dest->r = src->r;
|
||||
dest->typ = src->typ;
|
||||
dest->block_off = src->block_off;
|
||||
dest->is_finished = src->is_finished;
|
||||
block_iter_copy_from(&dest->bi, &src->bi);
|
||||
}
|
||||
|
||||
static int table_iter_next_in_block(struct table_iter *ti,
|
||||
struct reftable_record *rec)
|
||||
{
|
||||
int res = block_iter_next(&ti->bi, rec);
|
||||
if (res == 0 && reftable_record_type(rec) == BLOCK_TYPE_REF) {
|
||||
((struct reftable_ref_record *)rec->data)->update_index +=
|
||||
ti->r->min_update_index;
|
||||
}
|
||||
|
||||
return res;
|
||||
}
|
||||
|
||||
static void table_iter_block_done(struct table_iter *ti)
|
||||
{
|
||||
if (!ti->bi.br) {
|
||||
return;
|
||||
}
|
||||
reftable_block_done(&ti->bi.br->block);
|
||||
FREE_AND_NULL(ti->bi.br);
|
||||
|
||||
ti->bi.last_key.len = 0;
|
||||
ti->bi.next_off = 0;
|
||||
}
|
||||
|
||||
static int32_t extract_block_size(uint8_t *data, uint8_t *typ, uint64_t off,
|
||||
int version)
|
||||
{
|
||||
int32_t result = 0;
|
||||
|
||||
if (off == 0) {
|
||||
data += header_size(version);
|
||||
}
|
||||
|
||||
*typ = data[0];
|
||||
if (reftable_is_block_type(*typ)) {
|
||||
result = get_be24(data + 1);
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
int reader_init_block_reader(struct reftable_reader *r, struct block_reader *br,
|
||||
uint64_t next_off, uint8_t want_typ)
|
||||
{
|
||||
int32_t guess_block_size = r->block_size ? r->block_size :
|
||||
DEFAULT_BLOCK_SIZE;
|
||||
struct reftable_block block = { NULL };
|
||||
uint8_t block_typ = 0;
|
||||
int err = 0;
|
||||
uint32_t header_off = next_off ? 0 : header_size(r->version);
|
||||
int32_t block_size = 0;
|
||||
|
||||
if (next_off >= r->size)
|
||||
return 1;
|
||||
|
||||
err = reader_get_block(r, &block, next_off, guess_block_size);
|
||||
if (err < 0)
|
||||
return err;
|
||||
|
||||
block_size = extract_block_size(block.data, &block_typ, next_off,
|
||||
r->version);
|
||||
if (block_size < 0)
|
||||
return block_size;
|
||||
|
||||
if (want_typ != BLOCK_TYPE_ANY && block_typ != want_typ) {
|
||||
reftable_block_done(&block);
|
||||
return 1;
|
||||
}
|
||||
|
||||
if (block_size > guess_block_size) {
|
||||
reftable_block_done(&block);
|
||||
err = reader_get_block(r, &block, next_off, block_size);
|
||||
if (err < 0) {
|
||||
return err;
|
||||
}
|
||||
}
|
||||
|
||||
return block_reader_init(br, &block, header_off, r->block_size,
|
||||
hash_size(r->hash_id));
|
||||
}
|
||||
|
||||
static int table_iter_next_block(struct table_iter *dest,
|
||||
struct table_iter *src)
|
||||
{
|
||||
uint64_t next_block_off = src->block_off + src->bi.br->full_block_size;
|
||||
struct block_reader br = { 0 };
|
||||
int err = 0;
|
||||
|
||||
dest->r = src->r;
|
||||
dest->typ = src->typ;
|
||||
dest->block_off = next_block_off;
|
||||
|
||||
err = reader_init_block_reader(src->r, &br, next_block_off, src->typ);
|
||||
if (err > 0) {
|
||||
dest->is_finished = 1;
|
||||
return 1;
|
||||
}
|
||||
if (err != 0)
|
||||
return err;
|
||||
else {
|
||||
struct block_reader *brp =
|
||||
reftable_malloc(sizeof(struct block_reader));
|
||||
*brp = br;
|
||||
|
||||
dest->is_finished = 0;
|
||||
block_reader_start(brp, &dest->bi);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int table_iter_next(struct table_iter *ti, struct reftable_record *rec)
|
||||
{
|
||||
if (reftable_record_type(rec) != ti->typ)
|
||||
return REFTABLE_API_ERROR;
|
||||
|
||||
while (1) {
|
||||
struct table_iter next = TABLE_ITER_INIT;
|
||||
int err = 0;
|
||||
if (ti->is_finished) {
|
||||
return 1;
|
||||
}
|
||||
|
||||
err = table_iter_next_in_block(ti, rec);
|
||||
if (err <= 0) {
|
||||
return err;
|
||||
}
|
||||
|
||||
err = table_iter_next_block(&next, ti);
|
||||
if (err != 0) {
|
||||
ti->is_finished = 1;
|
||||
}
|
||||
table_iter_block_done(ti);
|
||||
if (err != 0) {
|
||||
return err;
|
||||
}
|
||||
table_iter_copy_from(ti, &next);
|
||||
block_iter_close(&next.bi);
|
||||
}
|
||||
}
|
||||
|
||||
static int table_iter_next_void(void *ti, struct reftable_record *rec)
|
||||
{
|
||||
return table_iter_next(ti, rec);
|
||||
}
|
||||
|
||||
static void table_iter_close(void *p)
|
||||
{
|
||||
struct table_iter *ti = p;
|
||||
table_iter_block_done(ti);
|
||||
block_iter_close(&ti->bi);
|
||||
}
|
||||
|
||||
static struct reftable_iterator_vtable table_iter_vtable = {
|
||||
.next = &table_iter_next_void,
|
||||
.close = &table_iter_close,
|
||||
};
|
||||
|
||||
static void iterator_from_table_iter(struct reftable_iterator *it,
|
||||
struct table_iter *ti)
|
||||
{
|
||||
assert(!it->ops);
|
||||
it->iter_arg = ti;
|
||||
it->ops = &table_iter_vtable;
|
||||
}
|
||||
|
||||
static int reader_table_iter_at(struct reftable_reader *r,
|
||||
struct table_iter *ti, uint64_t off,
|
||||
uint8_t typ)
|
||||
{
|
||||
struct block_reader br = { 0 };
|
||||
struct block_reader *brp = NULL;
|
||||
|
||||
int err = reader_init_block_reader(r, &br, off, typ);
|
||||
if (err != 0)
|
||||
return err;
|
||||
|
||||
brp = reftable_malloc(sizeof(struct block_reader));
|
||||
*brp = br;
|
||||
ti->r = r;
|
||||
ti->typ = block_reader_type(brp);
|
||||
ti->block_off = off;
|
||||
block_reader_start(brp, &ti->bi);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int reader_start(struct reftable_reader *r, struct table_iter *ti,
|
||||
uint8_t typ, int index)
|
||||
{
|
||||
struct reftable_reader_offsets *offs = reader_offsets_for(r, typ);
|
||||
uint64_t off = offs->offset;
|
||||
if (index) {
|
||||
off = offs->index_offset;
|
||||
if (off == 0) {
|
||||
return 1;
|
||||
}
|
||||
typ = BLOCK_TYPE_INDEX;
|
||||
}
|
||||
|
||||
return reader_table_iter_at(r, ti, off, typ);
|
||||
}
|
||||
|
||||
static int reader_seek_linear(struct reftable_reader *r, struct table_iter *ti,
|
||||
struct reftable_record *want)
|
||||
{
|
||||
struct reftable_record rec =
|
||||
reftable_new_record(reftable_record_type(want));
|
||||
struct strbuf want_key = STRBUF_INIT;
|
||||
struct strbuf got_key = STRBUF_INIT;
|
||||
struct table_iter next = TABLE_ITER_INIT;
|
||||
int err = -1;
|
||||
|
||||
reftable_record_key(want, &want_key);
|
||||
|
||||
while (1) {
|
||||
err = table_iter_next_block(&next, ti);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
if (err > 0) {
|
||||
break;
|
||||
}
|
||||
|
||||
err = block_reader_first_key(next.bi.br, &got_key);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
if (strbuf_cmp(&got_key, &want_key) > 0) {
|
||||
table_iter_block_done(&next);
|
||||
break;
|
||||
}
|
||||
|
||||
table_iter_block_done(ti);
|
||||
table_iter_copy_from(ti, &next);
|
||||
}
|
||||
|
||||
err = block_iter_seek(&ti->bi, &want_key);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
err = 0;
|
||||
|
||||
done:
|
||||
block_iter_close(&next.bi);
|
||||
reftable_record_destroy(&rec);
|
||||
strbuf_release(&want_key);
|
||||
strbuf_release(&got_key);
|
||||
return err;
|
||||
}
|
||||
|
||||
static int reader_seek_indexed(struct reftable_reader *r,
|
||||
struct reftable_iterator *it,
|
||||
struct reftable_record *rec)
|
||||
{
|
||||
struct reftable_index_record want_index = { .last_key = STRBUF_INIT };
|
||||
struct reftable_record want_index_rec = { NULL };
|
||||
struct reftable_index_record index_result = { .last_key = STRBUF_INIT };
|
||||
struct reftable_record index_result_rec = { NULL };
|
||||
struct table_iter index_iter = TABLE_ITER_INIT;
|
||||
struct table_iter next = TABLE_ITER_INIT;
|
||||
int err = 0;
|
||||
|
||||
reftable_record_key(rec, &want_index.last_key);
|
||||
reftable_record_from_index(&want_index_rec, &want_index);
|
||||
reftable_record_from_index(&index_result_rec, &index_result);
|
||||
|
||||
err = reader_start(r, &index_iter, reftable_record_type(rec), 1);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
err = reader_seek_linear(r, &index_iter, &want_index_rec);
|
||||
while (1) {
|
||||
err = table_iter_next(&index_iter, &index_result_rec);
|
||||
table_iter_block_done(&index_iter);
|
||||
if (err != 0)
|
||||
goto done;
|
||||
|
||||
err = reader_table_iter_at(r, &next, index_result.offset, 0);
|
||||
if (err != 0)
|
||||
goto done;
|
||||
|
||||
err = block_iter_seek(&next.bi, &want_index.last_key);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
if (next.typ == reftable_record_type(rec)) {
|
||||
err = 0;
|
||||
break;
|
||||
}
|
||||
|
||||
if (next.typ != BLOCK_TYPE_INDEX) {
|
||||
err = REFTABLE_FORMAT_ERROR;
|
||||
break;
|
||||
}
|
||||
|
||||
table_iter_copy_from(&index_iter, &next);
|
||||
}
|
||||
|
||||
if (err == 0) {
|
||||
struct table_iter empty = TABLE_ITER_INIT;
|
||||
struct table_iter *malloced =
|
||||
reftable_calloc(sizeof(struct table_iter));
|
||||
*malloced = empty;
|
||||
table_iter_copy_from(malloced, &next);
|
||||
iterator_from_table_iter(it, malloced);
|
||||
}
|
||||
done:
|
||||
block_iter_close(&next.bi);
|
||||
table_iter_close(&index_iter);
|
||||
reftable_record_release(&want_index_rec);
|
||||
reftable_record_release(&index_result_rec);
|
||||
return err;
|
||||
}
|
||||
|
||||
static int reader_seek_internal(struct reftable_reader *r,
|
||||
struct reftable_iterator *it,
|
||||
struct reftable_record *rec)
|
||||
{
|
||||
struct reftable_reader_offsets *offs =
|
||||
reader_offsets_for(r, reftable_record_type(rec));
|
||||
uint64_t idx = offs->index_offset;
|
||||
struct table_iter ti = TABLE_ITER_INIT;
|
||||
int err = 0;
|
||||
if (idx > 0)
|
||||
return reader_seek_indexed(r, it, rec);
|
||||
|
||||
err = reader_start(r, &ti, reftable_record_type(rec), 0);
|
||||
if (err < 0)
|
||||
return err;
|
||||
err = reader_seek_linear(r, &ti, rec);
|
||||
if (err < 0)
|
||||
return err;
|
||||
else {
|
||||
struct table_iter *p =
|
||||
reftable_malloc(sizeof(struct table_iter));
|
||||
*p = ti;
|
||||
iterator_from_table_iter(it, p);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int reader_seek(struct reftable_reader *r, struct reftable_iterator *it,
|
||||
struct reftable_record *rec)
|
||||
{
|
||||
uint8_t typ = reftable_record_type(rec);
|
||||
|
||||
struct reftable_reader_offsets *offs = reader_offsets_for(r, typ);
|
||||
if (!offs->is_present) {
|
||||
iterator_set_empty(it);
|
||||
return 0;
|
||||
}
|
||||
|
||||
return reader_seek_internal(r, it, rec);
|
||||
}
|
||||
|
||||
int reftable_reader_seek_ref(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, const char *name)
|
||||
{
|
||||
struct reftable_ref_record ref = {
|
||||
.refname = (char *)name,
|
||||
};
|
||||
struct reftable_record rec = { NULL };
|
||||
reftable_record_from_ref(&rec, &ref);
|
||||
return reader_seek(r, it, &rec);
|
||||
}
|
||||
|
||||
int reftable_reader_seek_log_at(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, const char *name,
|
||||
uint64_t update_index)
|
||||
{
|
||||
struct reftable_log_record log = {
|
||||
.refname = (char *)name,
|
||||
.update_index = update_index,
|
||||
};
|
||||
struct reftable_record rec = { NULL };
|
||||
reftable_record_from_log(&rec, &log);
|
||||
return reader_seek(r, it, &rec);
|
||||
}
|
||||
|
||||
int reftable_reader_seek_log(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, const char *name)
|
||||
{
|
||||
uint64_t max = ~((uint64_t)0);
|
||||
return reftable_reader_seek_log_at(r, it, name, max);
|
||||
}
|
||||
|
||||
void reader_close(struct reftable_reader *r)
|
||||
{
|
||||
block_source_close(&r->source);
|
||||
FREE_AND_NULL(r->name);
|
||||
}
|
||||
|
||||
int reftable_new_reader(struct reftable_reader **p,
|
||||
struct reftable_block_source *src, char const *name)
|
||||
{
|
||||
struct reftable_reader *rd =
|
||||
reftable_calloc(sizeof(struct reftable_reader));
|
||||
int err = init_reader(rd, src, name);
|
||||
if (err == 0) {
|
||||
*p = rd;
|
||||
} else {
|
||||
block_source_close(src);
|
||||
reftable_free(rd);
|
||||
}
|
||||
return err;
|
||||
}
|
||||
|
||||
void reftable_reader_free(struct reftable_reader *r)
|
||||
{
|
||||
reader_close(r);
|
||||
reftable_free(r);
|
||||
}
|
||||
|
||||
static int reftable_reader_refs_for_indexed(struct reftable_reader *r,
|
||||
struct reftable_iterator *it,
|
||||
uint8_t *oid)
|
||||
{
|
||||
struct reftable_obj_record want = {
|
||||
.hash_prefix = oid,
|
||||
.hash_prefix_len = r->object_id_len,
|
||||
};
|
||||
struct reftable_record want_rec = { NULL };
|
||||
struct reftable_iterator oit = { NULL };
|
||||
struct reftable_obj_record got = { NULL };
|
||||
struct reftable_record got_rec = { NULL };
|
||||
int err = 0;
|
||||
struct indexed_table_ref_iter *itr = NULL;
|
||||
|
||||
/* Look through the reverse index. */
|
||||
reftable_record_from_obj(&want_rec, &want);
|
||||
err = reader_seek(r, &oit, &want_rec);
|
||||
if (err != 0)
|
||||
goto done;
|
||||
|
||||
/* read out the reftable_obj_record */
|
||||
reftable_record_from_obj(&got_rec, &got);
|
||||
err = iterator_next(&oit, &got_rec);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
if (err > 0 ||
|
||||
memcmp(want.hash_prefix, got.hash_prefix, r->object_id_len)) {
|
||||
/* didn't find it; return empty iterator */
|
||||
iterator_set_empty(it);
|
||||
err = 0;
|
||||
goto done;
|
||||
}
|
||||
|
||||
err = new_indexed_table_ref_iter(&itr, r, oid, hash_size(r->hash_id),
|
||||
got.offsets, got.offset_len);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
got.offsets = NULL;
|
||||
iterator_from_indexed_table_ref_iter(it, itr);
|
||||
|
||||
done:
|
||||
reftable_iterator_destroy(&oit);
|
||||
reftable_record_release(&got_rec);
|
||||
return err;
|
||||
}
|
||||
|
||||
static int reftable_reader_refs_for_unindexed(struct reftable_reader *r,
|
||||
struct reftable_iterator *it,
|
||||
uint8_t *oid)
|
||||
{
|
||||
struct table_iter ti_empty = TABLE_ITER_INIT;
|
||||
struct table_iter *ti = reftable_calloc(sizeof(struct table_iter));
|
||||
struct filtering_ref_iterator *filter = NULL;
|
||||
struct filtering_ref_iterator empty = FILTERING_REF_ITERATOR_INIT;
|
||||
int oid_len = hash_size(r->hash_id);
|
||||
int err;
|
||||
|
||||
*ti = ti_empty;
|
||||
err = reader_start(r, ti, BLOCK_TYPE_REF, 0);
|
||||
if (err < 0) {
|
||||
reftable_free(ti);
|
||||
return err;
|
||||
}
|
||||
|
||||
filter = reftable_malloc(sizeof(struct filtering_ref_iterator));
|
||||
*filter = empty;
|
||||
|
||||
strbuf_add(&filter->oid, oid, oid_len);
|
||||
reftable_table_from_reader(&filter->tab, r);
|
||||
filter->double_check = 0;
|
||||
iterator_from_table_iter(&filter->it, ti);
|
||||
|
||||
iterator_from_filtering_ref_iterator(it, filter);
|
||||
return 0;
|
||||
}
|
||||
|
||||
int reftable_reader_refs_for(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, uint8_t *oid)
|
||||
{
|
||||
if (r->obj_offsets.is_present)
|
||||
return reftable_reader_refs_for_indexed(r, it, oid);
|
||||
return reftable_reader_refs_for_unindexed(r, it, oid);
|
||||
}
|
||||
|
||||
uint64_t reftable_reader_max_update_index(struct reftable_reader *r)
|
||||
{
|
||||
return r->max_update_index;
|
||||
}
|
||||
|
||||
uint64_t reftable_reader_min_update_index(struct reftable_reader *r)
|
||||
{
|
||||
return r->min_update_index;
|
||||
}
|
||||
|
||||
/* generic table interface. */
|
||||
|
||||
static int reftable_reader_seek_void(void *tab, struct reftable_iterator *it,
|
||||
struct reftable_record *rec)
|
||||
{
|
||||
return reader_seek(tab, it, rec);
|
||||
}
|
||||
|
||||
static uint32_t reftable_reader_hash_id_void(void *tab)
|
||||
{
|
||||
return reftable_reader_hash_id(tab);
|
||||
}
|
||||
|
||||
static uint64_t reftable_reader_min_update_index_void(void *tab)
|
||||
{
|
||||
return reftable_reader_min_update_index(tab);
|
||||
}
|
||||
|
||||
static uint64_t reftable_reader_max_update_index_void(void *tab)
|
||||
{
|
||||
return reftable_reader_max_update_index(tab);
|
||||
}
|
||||
|
||||
static struct reftable_table_vtable reader_vtable = {
|
||||
.seek_record = reftable_reader_seek_void,
|
||||
.hash_id = reftable_reader_hash_id_void,
|
||||
.min_update_index = reftable_reader_min_update_index_void,
|
||||
.max_update_index = reftable_reader_max_update_index_void,
|
||||
};
|
||||
|
||||
void reftable_table_from_reader(struct reftable_table *tab,
|
||||
struct reftable_reader *reader)
|
||||
{
|
||||
assert(!tab->ops);
|
||||
tab->ops = &reader_vtable;
|
||||
tab->table_arg = reader;
|
||||
}
|
||||
|
||||
|
||||
int reftable_reader_print_file(const char *tablename)
|
||||
{
|
||||
struct reftable_block_source src = { NULL };
|
||||
int err = reftable_block_source_from_file(&src, tablename);
|
||||
struct reftable_reader *r = NULL;
|
||||
struct reftable_table tab = { NULL };
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
err = reftable_new_reader(&r, &src, tablename);
|
||||
if (err < 0)
|
||||
goto done;
|
||||
|
||||
reftable_table_from_reader(&tab, r);
|
||||
err = reftable_table_print(&tab);
|
||||
done:
|
||||
reftable_reader_free(r);
|
||||
return err;
|
||||
}
|
||||
|
|
@ -0,0 +1,64 @@
|
|||
/*
|
||||
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 READER_H
|
||||
#define READER_H
|
||||
|
||||
#include "block.h"
|
||||
#include "record.h"
|
||||
#include "reftable-iterator.h"
|
||||
#include "reftable-reader.h"
|
||||
|
||||
uint64_t block_source_size(struct reftable_block_source *source);
|
||||
|
||||
int block_source_read_block(struct reftable_block_source *source,
|
||||
struct reftable_block *dest, uint64_t off,
|
||||
uint32_t size);
|
||||
void block_source_close(struct reftable_block_source *source);
|
||||
|
||||
/* metadata for a block type */
|
||||
struct reftable_reader_offsets {
|
||||
int is_present;
|
||||
uint64_t offset;
|
||||
uint64_t index_offset;
|
||||
};
|
||||
|
||||
/* The state for reading a reftable file. */
|
||||
struct reftable_reader {
|
||||
/* for convience, associate a name with the instance. */
|
||||
char *name;
|
||||
struct reftable_block_source source;
|
||||
|
||||
/* Size of the file, excluding the footer. */
|
||||
uint64_t size;
|
||||
|
||||
/* 'sha1' for SHA1, 's256' for SHA-256 */
|
||||
uint32_t hash_id;
|
||||
|
||||
uint32_t block_size;
|
||||
uint64_t min_update_index;
|
||||
uint64_t max_update_index;
|
||||
/* Length of the OID keys in the 'o' section */
|
||||
int object_id_len;
|
||||
int version;
|
||||
|
||||
struct reftable_reader_offsets ref_offsets;
|
||||
struct reftable_reader_offsets obj_offsets;
|
||||
struct reftable_reader_offsets log_offsets;
|
||||
};
|
||||
|
||||
int init_reader(struct reftable_reader *r, struct reftable_block_source *source,
|
||||
const char *name);
|
||||
void reader_close(struct reftable_reader *r);
|
||||
const char *reader_name(struct reftable_reader *r);
|
||||
|
||||
/* initialize a block reader to read from `r` */
|
||||
int reader_init_block_reader(struct reftable_reader *r, struct block_reader *br,
|
||||
uint64_t next_off, uint8_t want_typ);
|
||||
|
||||
#endif
|
||||
|
|
@ -0,0 +1,101 @@
|
|||
/*
|
||||
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 REFTABLE_READER_H
|
||||
#define REFTABLE_READER_H
|
||||
|
||||
#include "reftable-iterator.h"
|
||||
#include "reftable-blocksource.h"
|
||||
|
||||
/*
|
||||
* Reading single tables
|
||||
*
|
||||
* The follow routines are for reading single files. For an
|
||||
* application-level interface, skip ahead to struct
|
||||
* reftable_merged_table and struct reftable_stack.
|
||||
*/
|
||||
|
||||
/* The reader struct is a handle to an open reftable file. */
|
||||
struct reftable_reader;
|
||||
|
||||
/* Generic table. */
|
||||
struct reftable_table;
|
||||
|
||||
/* reftable_new_reader opens a reftable for reading. If successful,
|
||||
* returns 0 code and sets pp. The name is used for creating a
|
||||
* stack. Typically, it is the basename of the file. The block source
|
||||
* `src` is owned by the reader, and is closed on calling
|
||||
* reftable_reader_destroy(). On error, the block source `src` is
|
||||
* closed as well.
|
||||
*/
|
||||
int reftable_new_reader(struct reftable_reader **pp,
|
||||
struct reftable_block_source *src, const char *name);
|
||||
|
||||
/* reftable_reader_seek_ref returns an iterator where 'name' would be inserted
|
||||
in the table. To seek to the start of the table, use name = "".
|
||||
|
||||
example:
|
||||
|
||||
struct reftable_reader *r = NULL;
|
||||
int err = reftable_new_reader(&r, &src, "filename");
|
||||
if (err < 0) { ... }
|
||||
struct reftable_iterator it = {0};
|
||||
err = reftable_reader_seek_ref(r, &it, "refs/heads/master");
|
||||
if (err < 0) { ... }
|
||||
struct reftable_ref_record ref = {0};
|
||||
while (1) {
|
||||
err = reftable_iterator_next_ref(&it, &ref);
|
||||
if (err > 0) {
|
||||
break;
|
||||
}
|
||||
if (err < 0) {
|
||||
..error handling..
|
||||
}
|
||||
..found..
|
||||
}
|
||||
reftable_iterator_destroy(&it);
|
||||
reftable_ref_record_release(&ref);
|
||||
*/
|
||||
int reftable_reader_seek_ref(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, const char *name);
|
||||
|
||||
/* returns the hash ID used in this table. */
|
||||
uint32_t reftable_reader_hash_id(struct reftable_reader *r);
|
||||
|
||||
/* seek to logs for the given name, older than update_index. To seek to the
|
||||
start of the table, use name = "".
|
||||
*/
|
||||
int reftable_reader_seek_log_at(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, const char *name,
|
||||
uint64_t update_index);
|
||||
|
||||
/* seek to newest log entry for given name. */
|
||||
int reftable_reader_seek_log(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, const char *name);
|
||||
|
||||
/* closes and deallocates a reader. */
|
||||
void reftable_reader_free(struct reftable_reader *);
|
||||
|
||||
/* return an iterator for the refs pointing to `oid`. */
|
||||
int reftable_reader_refs_for(struct reftable_reader *r,
|
||||
struct reftable_iterator *it, uint8_t *oid);
|
||||
|
||||
/* return the max_update_index for a table */
|
||||
uint64_t reftable_reader_max_update_index(struct reftable_reader *r);
|
||||
|
||||
/* return the min_update_index for a table */
|
||||
uint64_t reftable_reader_min_update_index(struct reftable_reader *r);
|
||||
|
||||
/* creates a generic table from a file reader. */
|
||||
void reftable_table_from_reader(struct reftable_table *tab,
|
||||
struct reftable_reader *reader);
|
||||
|
||||
/* print table onto stdout for debugging. */
|
||||
int reftable_reader_print_file(const char *tablename);
|
||||
|
||||
#endif
|
||||
Loading…
Reference in New Issue