b8ca235ca5
The merged table provides access to a reftable stack by merging the contents of those tables into a virtual table. These subtables are being tracked via `struct reftable_table`, which is a generic interface for accessing either a single reftable or a merged reftable. So in theory, it would be possible for the merged table to merge together other merged tables. This is somewhat nonsensical though: we only ever set up a merged table over normal reftables, and there is no reason to do otherwise. This generic interface thus makes the code way harder to follow and reason about than really necessary. The abstraction layer may also have an impact on performance, even though the extra set of vtable function calls probably doesn't really matter. Refactor the merged tables to use a `struct reftable_reader` for each of the subtables instead, which gives us direct access to the underlying tables. Adjust names accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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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 READER_H
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#define READER_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-reader.h"
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uint64_t block_source_size(struct reftable_block_source *source);
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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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void block_source_close(struct reftable_block_source *source);
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/* metadata for a block type */
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struct reftable_reader_offsets {
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int is_present;
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uint64_t offset;
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uint64_t index_offset;
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};
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/* The state for reading a reftable file. */
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struct reftable_reader {
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/* for convience, associate a name with the instance. */
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char *name;
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struct reftable_block_source source;
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/* Size of the file, excluding the footer. */
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uint64_t size;
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/* 'sha1' for SHA1, 's256' for SHA-256 */
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uint32_t hash_id;
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uint32_t block_size;
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uint64_t min_update_index;
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uint64_t max_update_index;
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/* Length of the OID keys in the 'o' section */
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int object_id_len;
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int version;
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struct reftable_reader_offsets ref_offsets;
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struct reftable_reader_offsets obj_offsets;
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struct reftable_reader_offsets log_offsets;
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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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void reader_close(struct reftable_reader *r);
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const char *reader_name(struct reftable_reader *r);
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void reader_init_iter(struct reftable_reader *r,
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struct reftable_iterator *it,
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uint8_t typ);
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/* initialize a block reader to read from `r` */
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int reader_init_block_reader(struct reftable_reader *r, struct block_reader *br,
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uint64_t next_off, uint8_t want_typ);
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#endif
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