2 Copyright 2020 Google LLC
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
16 #include "reftable-record.h"
19 * A substring of existing string data. This structure takes no responsibility
20 * for the lifetime of the data it points to.
27 /* Advance `s.buf` by `n`, and decrease length. */
28 static inline void string_view_consume(struct string_view
*s
, int n
)
34 /* utilities for de/encoding varints */
36 int get_var_int(uint64_t *dest
, struct string_view
*in
);
37 int put_var_int(struct string_view
*dest
, uint64_t val
);
39 /* Methods for records. */
40 struct reftable_record_vtable
{
41 /* encode the key of to a uint8_t strbuf. */
42 void (*key
)(const void *rec
, struct strbuf
*dest
);
44 /* The record type of ('r' for ref). */
47 void (*copy_from
)(void *dest
, const void *src
, int hash_size
);
49 /* a value of [0..7], indicating record subvariants (eg. ref vs. symref
51 uint8_t (*val_type
)(const void *rec
);
53 /* encodes rec into dest, returning how much space was used. */
54 int (*encode
)(const void *rec
, struct string_view dest
, int hash_size
);
56 /* decode data from `src` into the record. */
57 int (*decode
)(void *rec
, struct strbuf key
, uint8_t extra
,
58 struct string_view src
, int hash_size
,
59 struct strbuf
*scratch
);
61 /* deallocate and null the record. */
62 void (*release
)(void *rec
);
64 /* is this a tombstone? */
65 int (*is_deletion
)(const void *rec
);
67 /* Are two records equal? This assumes they have the same type. Returns 0 for non-equal. */
68 int (*equal
)(const void *a
, const void *b
, int hash_size
);
71 * Compare keys of two records with each other. The records must have
74 int (*cmp
)(const void *a
, const void *b
);
76 /* Print on stdout, for debugging. */
77 void (*print
)(const void *rec
, int hash_size
);
80 /* returns true for recognized block types. Block start with the block type. */
81 int reftable_is_block_type(uint8_t typ
);
83 /* Encode `key` into `dest`. Sets `is_restart` to indicate a restart. Returns
84 * number of bytes written. */
85 int reftable_encode_key(int *is_restart
, struct string_view dest
,
86 struct strbuf prev_key
, struct strbuf key
,
90 * Decode into `last_key` and `extra` from `in`. `last_key` is expected to
91 * contain the decoded key of the preceding record, if any.
93 int reftable_decode_key(struct strbuf
*last_key
, uint8_t *extra
,
94 struct string_view in
);
96 /* reftable_index_record are used internally to speed up lookups. */
97 struct reftable_index_record
{
98 uint64_t offset
; /* Offset of block */
99 struct strbuf last_key
; /* Last key of the block. */
102 /* reftable_obj_record stores an object ID => ref mapping. */
103 struct reftable_obj_record
{
104 uint8_t *hash_prefix
; /* leading bytes of the object ID */
105 int hash_prefix_len
; /* number of leading bytes. Constant
106 * across a single table. */
107 uint64_t *offsets
; /* a vector of file offsets. */
111 /* record is a generic wrapper for different types of records. It is normally
112 * created on the stack, or embedded within another struct. If the type is
113 * known, a fresh instance can be initialized explicitly. Otherwise, use
114 * `reftable_record_init()` to initialize generically (as the index_record is
115 * not valid as 0-initialized structure)
117 struct reftable_record
{
120 struct reftable_ref_record ref
;
121 struct reftable_log_record log
;
122 struct reftable_obj_record obj
;
123 struct reftable_index_record idx
;
127 /* Initialize the reftable record for the given type */
128 void reftable_record_init(struct reftable_record
*rec
, uint8_t typ
);
130 /* see struct record_vtable */
131 int reftable_record_cmp(struct reftable_record
*a
, struct reftable_record
*b
);
132 int reftable_record_equal(struct reftable_record
*a
, struct reftable_record
*b
, int hash_size
);
133 void reftable_record_print(struct reftable_record
*rec
, int hash_size
);
134 void reftable_record_key(struct reftable_record
*rec
, struct strbuf
*dest
);
135 void reftable_record_copy_from(struct reftable_record
*rec
,
136 struct reftable_record
*src
, int hash_size
);
137 uint8_t reftable_record_val_type(struct reftable_record
*rec
);
138 int reftable_record_encode(struct reftable_record
*rec
, struct string_view dest
,
140 int reftable_record_decode(struct reftable_record
*rec
, struct strbuf key
,
141 uint8_t extra
, struct string_view src
,
142 int hash_size
, struct strbuf
*scratch
);
143 int reftable_record_is_deletion(struct reftable_record
*rec
);
145 static inline uint8_t reftable_record_type(struct reftable_record
*rec
)
150 /* frees and zeroes out the embedded record */
151 void reftable_record_release(struct reftable_record
*rec
);
154 int reftable_ref_record_compare_name(const void *a
, const void *b
);
157 int reftable_log_record_compare_key(const void *a
, const void *b
);