Merge branch 'ep/maint-equals-null-cocci' for maint-2.35
[alt-git.git] / reftable / record.h
blob498e8c50bf4f02eb13bc653fe11006a861f6ab9e
1 /*
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
7 */
9 #ifndef RECORD_H
10 #define RECORD_H
12 #include "system.h"
14 #include <stdint.h>
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.
22 struct string_view {
23 uint8_t *buf;
24 size_t len;
27 /* Advance `s.buf` by `n`, and decrease length. */
28 void string_view_consume(struct string_view *s, int n);
30 /* utilities for de/encoding varints */
32 int get_var_int(uint64_t *dest, struct string_view *in);
33 int put_var_int(struct string_view *dest, uint64_t val);
35 /* Methods for records. */
36 struct reftable_record_vtable {
37 /* encode the key of to a uint8_t strbuf. */
38 void (*key)(const void *rec, struct strbuf *dest);
40 /* The record type of ('r' for ref). */
41 uint8_t type;
43 void (*copy_from)(void *dest, const void *src, int hash_size);
45 /* a value of [0..7], indicating record subvariants (eg. ref vs. symref
46 * vs ref deletion) */
47 uint8_t (*val_type)(const void *rec);
49 /* encodes rec into dest, returning how much space was used. */
50 int (*encode)(const void *rec, struct string_view dest, int hash_size);
52 /* decode data from `src` into the record. */
53 int (*decode)(void *rec, struct strbuf key, uint8_t extra,
54 struct string_view src, int hash_size);
56 /* deallocate and null the record. */
57 void (*release)(void *rec);
59 /* is this a tombstone? */
60 int (*is_deletion)(const void *rec);
63 /* record is a generic wrapper for different types of records. */
64 struct reftable_record {
65 void *data;
66 struct reftable_record_vtable *ops;
69 /* returns true for recognized block types. Block start with the block type. */
70 int reftable_is_block_type(uint8_t typ);
72 /* creates a malloced record of the given type. Dispose with record_destroy */
73 struct reftable_record reftable_new_record(uint8_t typ);
75 /* Encode `key` into `dest`. Sets `is_restart` to indicate a restart. Returns
76 * number of bytes written. */
77 int reftable_encode_key(int *is_restart, struct string_view dest,
78 struct strbuf prev_key, struct strbuf key,
79 uint8_t extra);
81 /* Decode into `key` and `extra` from `in` */
82 int reftable_decode_key(struct strbuf *key, uint8_t *extra,
83 struct strbuf last_key, struct string_view in);
85 /* reftable_index_record are used internally to speed up lookups. */
86 struct reftable_index_record {
87 uint64_t offset; /* Offset of block */
88 struct strbuf last_key; /* Last key of the block. */
91 /* reftable_obj_record stores an object ID => ref mapping. */
92 struct reftable_obj_record {
93 uint8_t *hash_prefix; /* leading bytes of the object ID */
94 int hash_prefix_len; /* number of leading bytes. Constant
95 * across a single table. */
96 uint64_t *offsets; /* a vector of file offsets. */
97 int offset_len;
100 /* see struct record_vtable */
102 void reftable_record_key(struct reftable_record *rec, struct strbuf *dest);
103 uint8_t reftable_record_type(struct reftable_record *rec);
104 void reftable_record_copy_from(struct reftable_record *rec,
105 struct reftable_record *src, int hash_size);
106 uint8_t reftable_record_val_type(struct reftable_record *rec);
107 int reftable_record_encode(struct reftable_record *rec, struct string_view dest,
108 int hash_size);
109 int reftable_record_decode(struct reftable_record *rec, struct strbuf key,
110 uint8_t extra, struct string_view src,
111 int hash_size);
112 int reftable_record_is_deletion(struct reftable_record *rec);
114 /* zeroes out the embedded record */
115 void reftable_record_release(struct reftable_record *rec);
117 /* clear and deallocate embedded record, and zero `rec`. */
118 void reftable_record_destroy(struct reftable_record *rec);
120 /* initialize generic records from concrete records. The generic record should
121 * be zeroed out. */
122 void reftable_record_from_obj(struct reftable_record *rec,
123 struct reftable_obj_record *objrec);
124 void reftable_record_from_index(struct reftable_record *rec,
125 struct reftable_index_record *idxrec);
126 void reftable_record_from_ref(struct reftable_record *rec,
127 struct reftable_ref_record *refrec);
128 void reftable_record_from_log(struct reftable_record *rec,
129 struct reftable_log_record *logrec);
130 struct reftable_ref_record *reftable_record_as_ref(struct reftable_record *ref);
131 struct reftable_log_record *reftable_record_as_log(struct reftable_record *ref);
133 /* for qsort. */
134 int reftable_ref_record_compare_name(const void *a, const void *b);
136 /* for qsort. */
137 int reftable_log_record_compare_key(const void *a, const void *b);
139 #endif