reftable-record.h · leroysheep/MovieWebApp

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1	/*
2	* Copyright 2020 Google LLC
3	*
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	*/
8
9	#ifndef REFTABLE_RECORD_H
10	#define REFTABLE_RECORD_H
11
12	#include "reftable-system.h"
13	#include "reftable-basics.h"
14
15	/*
16	* Basic data types
17	*
18	* Reftables store the state of each ref in struct reftable_ref_record, and they
19	* store a sequence of reflog updates in struct reftable_log_record.
20	*/
21
22	/* reftable_ref_record holds a ref database entry target_value */
23	struct reftable_ref_record {
24	char refname; / Name of the ref, malloced. */
25	size_t refname_cap;
26	uint64_t update_index; /* Logical timestamp at which this value is
27	* written */
28
29	enum {
30	/* tombstone to hide deletions from earlier tables */
31	REFTABLE_REF_DELETION = 0x0,
32
33	/* a simple ref */
34	REFTABLE_REF_VAL1 = 0x1,
35	/* a tag, plus its peeled hash */
36	REFTABLE_REF_VAL2 = 0x2,
37
38	/* a symbolic reference */
39	REFTABLE_REF_SYMREF = 0x3,
40	#define REFTABLE_NR_REF_VALUETYPES 4
41	} value_type;
42	union {
43	unsigned char val1[REFTABLE_HASH_SIZE_MAX];
44	struct {
45	unsigned char value[REFTABLE_HASH_SIZE_MAX]; /* first hash */
46	unsigned char target_value[REFTABLE_HASH_SIZE_MAX]; /* second hash */
47	} val2;
48	char symref; / referent, malloced 0-terminated string */
49	} value;
50	};
51
52	/* Returns the first hash, or NULL if `rec` is not of type
53	* REFTABLE_REF_VAL1 or REFTABLE_REF_VAL2. */
54	const unsigned char reftable_ref_record_val1(const struct reftable_ref_record rec);
55
56	/* Returns the second hash, or NULL if `rec` is not of type
57	* REFTABLE_REF_VAL2. */
58	const unsigned char reftable_ref_record_val2(const struct reftable_ref_record rec);
59
60	/* returns whether 'ref' represents a deletion */
61	int reftable_ref_record_is_deletion(const struct reftable_ref_record *ref);
62
63	/* frees and nulls all pointer values inside `ref`. */
64	void reftable_ref_record_release(struct reftable_ref_record *ref);
65
66	/* returns whether two reftable_ref_records are the same. Useful for testing. */
67	int reftable_ref_record_equal(const struct reftable_ref_record *a,
68	const struct reftable_ref_record *b, uint32_t hash_size);
69
70	/* reftable_log_record holds a reflog entry */
71	struct reftable_log_record {
72	char *refname;
73	size_t refname_cap;
74	uint64_t update_index; /* logical timestamp of a transactional update.
75	*/
76
77	enum {
78	/* tombstone to hide deletions from earlier tables */
79	REFTABLE_LOG_DELETION = 0x0,
80
81	/* a simple update */
82	REFTABLE_LOG_UPDATE = 0x1,
83	#define REFTABLE_NR_LOG_VALUETYPES 2
84	} value_type;
85
86	union {
87	struct {
88	unsigned char new_hash[REFTABLE_HASH_SIZE_MAX];
89	unsigned char old_hash[REFTABLE_HASH_SIZE_MAX];
90	char *name;
91	char *email;
92	uint64_t time;
93	int16_t tz_offset;
94	char *message;
95	size_t message_cap;
96	} update;
97	} value;
98	};
99
100	/* returns whether 'ref' represents the deletion of a log record. */
101	int reftable_log_record_is_deletion(const struct reftable_log_record *log);
102
103	/* frees and nulls all pointer values. */
104	void reftable_log_record_release(struct reftable_log_record *log);
105
106	/* returns whether two records are equal. Useful for testing. */
107	int reftable_log_record_equal(const struct reftable_log_record *a,
108	const struct reftable_log_record *b, uint32_t hash_size);
109
110	#endif