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140 lines
4.5 KiB
140 lines
4.5 KiB
/* |
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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 RECORD_H |
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#define RECORD_H |
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#include "system.h" |
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#include <stdint.h> |
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#include "reftable-record.h" |
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/* |
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* A substring of existing string data. This structure takes no responsibility |
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* for the lifetime of the data it points to. |
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*/ |
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struct string_view { |
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uint8_t *buf; |
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size_t len; |
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}; |
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/* Advance `s.buf` by `n`, and decrease length. */ |
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void string_view_consume(struct string_view *s, int n); |
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/* utilities for de/encoding varints */ |
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int get_var_int(uint64_t *dest, struct string_view *in); |
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int put_var_int(struct string_view *dest, uint64_t val); |
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/* Methods for records. */ |
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struct reftable_record_vtable { |
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/* encode the key of to a uint8_t strbuf. */ |
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void (*key)(const void *rec, struct strbuf *dest); |
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/* The record type of ('r' for ref). */ |
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uint8_t type; |
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void (*copy_from)(void *dest, const void *src, int hash_size); |
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/* a value of [0..7], indicating record subvariants (eg. ref vs. symref |
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* vs ref deletion) */ |
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uint8_t (*val_type)(const void *rec); |
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/* encodes rec into dest, returning how much space was used. */ |
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int (*encode)(const void *rec, struct string_view dest, int hash_size); |
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/* decode data from `src` into the record. */ |
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int (*decode)(void *rec, struct strbuf key, uint8_t extra, |
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struct string_view src, int hash_size); |
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/* deallocate and null the record. */ |
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void (*release)(void *rec); |
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/* is this a tombstone? */ |
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int (*is_deletion)(const void *rec); |
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/* Are two records equal? This assumes they have the same type. Returns 0 for non-equal. */ |
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int (*equal)(const void *a, const void *b, int hash_size); |
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/* Print on stdout, for debugging. */ |
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void (*print)(const void *rec, int hash_size); |
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}; |
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/* returns true for recognized block types. Block start with the block type. */ |
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int reftable_is_block_type(uint8_t typ); |
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/* return an initialized record for the given type */ |
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struct reftable_record reftable_new_record(uint8_t typ); |
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/* Encode `key` into `dest`. Sets `is_restart` to indicate a restart. Returns |
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* number of bytes written. */ |
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int reftable_encode_key(int *is_restart, struct string_view dest, |
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struct strbuf prev_key, struct strbuf key, |
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uint8_t extra); |
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/* Decode into `key` and `extra` from `in` */ |
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int reftable_decode_key(struct strbuf *key, uint8_t *extra, |
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struct strbuf last_key, struct string_view in); |
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/* reftable_index_record are used internally to speed up lookups. */ |
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struct reftable_index_record { |
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uint64_t offset; /* Offset of block */ |
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struct strbuf last_key; /* Last key of the block. */ |
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}; |
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/* reftable_obj_record stores an object ID => ref mapping. */ |
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struct reftable_obj_record { |
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uint8_t *hash_prefix; /* leading bytes of the object ID */ |
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int hash_prefix_len; /* number of leading bytes. Constant |
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* across a single table. */ |
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uint64_t *offsets; /* a vector of file offsets. */ |
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int offset_len; |
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}; |
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/* record is a generic wrapper for different types of records. It is normally |
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* created on the stack, or embedded within another struct. If the type is |
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* known, a fresh instance can be initialized explicitly. Otherwise, use |
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* reftable_new_record() to initialize generically (as the index_record is not |
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* valid as 0-initialized structure) |
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*/ |
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struct reftable_record { |
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uint8_t type; |
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union { |
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struct reftable_ref_record ref; |
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struct reftable_log_record log; |
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struct reftable_obj_record obj; |
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struct reftable_index_record idx; |
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} u; |
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}; |
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/* see struct record_vtable */ |
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int reftable_record_equal(struct reftable_record *a, struct reftable_record *b, int hash_size); |
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void reftable_record_print(struct reftable_record *rec, int hash_size); |
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void reftable_record_key(struct reftable_record *rec, struct strbuf *dest); |
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uint8_t reftable_record_type(struct reftable_record *rec); |
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void reftable_record_copy_from(struct reftable_record *rec, |
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struct reftable_record *src, int hash_size); |
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uint8_t reftable_record_val_type(struct reftable_record *rec); |
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int reftable_record_encode(struct reftable_record *rec, struct string_view dest, |
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int hash_size); |
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int reftable_record_decode(struct reftable_record *rec, struct strbuf key, |
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uint8_t extra, struct string_view src, |
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int hash_size); |
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int reftable_record_is_deletion(struct reftable_record *rec); |
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/* frees and zeroes out the embedded record */ |
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void reftable_record_release(struct reftable_record *rec); |
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/* for qsort. */ |
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int reftable_ref_record_compare_name(const void *a, const void *b); |
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/* for qsort. */ |
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int reftable_log_record_compare_key(const void *a, const void *b); |
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#endif
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