1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#ifndef INCLUDE_sys_git_odb_backend_h__
#define INCLUDE_sys_git_odb_backend_h__
#include "git2/common.h"
#include "git2/types.h"
#include "git2/oid.h"
#include "git2/odb.h"
/**
* @file git2/sys/backend.h
* @brief Git custom backend implementors functions
* @defgroup git_backend Git custom backend APIs
* @ingroup Git
* @{
*/
GIT_BEGIN_DECL
/**
* An instance for a custom backend
*/
struct git_odb_backend {
unsigned int version;
git_odb *odb;
/* read and read_prefix each return to libgit2 a buffer which
* will be freed later. The buffer should be allocated using
* the function git_odb_backend_data_alloc to ensure that libgit2
* can safely free it later. */
int GIT_CALLBACK(read)(
void **, size_t *, git_object_t *, git_odb_backend *, const git_oid *);
/* To find a unique object given a prefix of its oid. The oid given
* must be so that the remaining (GIT_OID_SHA1_HEXSIZE - len)*4 bits are 0s.
*/
int GIT_CALLBACK(read_prefix)(
git_oid *, void **, size_t *, git_object_t *,
git_odb_backend *, const git_oid *, size_t);
int GIT_CALLBACK(read_header)(
size_t *, git_object_t *, git_odb_backend *, const git_oid *);
/**
* Write an object into the backend. The id of the object has
* already been calculated and is passed in.
*/
int GIT_CALLBACK(write)(
git_odb_backend *, const git_oid *, const void *, size_t, git_object_t);
int GIT_CALLBACK(writestream)(
git_odb_stream **, git_odb_backend *, git_object_size_t, git_object_t);
int GIT_CALLBACK(readstream)(
git_odb_stream **, size_t *, git_object_t *,
git_odb_backend *, const git_oid *);
int GIT_CALLBACK(exists)(
git_odb_backend *, const git_oid *);
int GIT_CALLBACK(exists_prefix)(
git_oid *, git_odb_backend *, const git_oid *, size_t);
/**
* If the backend implements a refreshing mechanism, it should be exposed
* through this endpoint. Each call to `git_odb_refresh()` will invoke it.
*
* The odb layer will automatically call this when needed on failed
* lookups (ie. `exists()`, `read()`, `read_header()`).
*/
int GIT_CALLBACK(refresh)(git_odb_backend *);
int GIT_CALLBACK(foreach)(
git_odb_backend *, git_odb_foreach_cb cb, void *payload);
int GIT_CALLBACK(writepack)(
git_odb_writepack **, git_odb_backend *, git_odb *odb,
git_indexer_progress_cb progress_cb, void *progress_payload);
/**
* If the backend supports pack files, this will create a
* `multi-pack-index` file which will contain an index of all objects
* across all the `.pack` files.
*/
int GIT_CALLBACK(writemidx)(git_odb_backend *);
/**
* "Freshens" an already existing object, updating its last-used
* time. This occurs when `git_odb_write` was called, but the
* object already existed (and will not be re-written). The
* underlying implementation may want to update last-used timestamps.
*
* If callers implement this, they should return `0` if the object
* exists and was freshened, and non-zero otherwise.
*/
int GIT_CALLBACK(freshen)(git_odb_backend *, const git_oid *);
/**
* Frees any resources held by the odb (including the `git_odb_backend`
* itself). An odb backend implementation must provide this function.
*/
void GIT_CALLBACK(free)(git_odb_backend *);
};
#define GIT_ODB_BACKEND_VERSION 1
#define GIT_ODB_BACKEND_INIT {GIT_ODB_BACKEND_VERSION}
/**
* Initializes a `git_odb_backend` with default values. Equivalent to
* creating an instance with GIT_ODB_BACKEND_INIT.
*
* @param backend the `git_odb_backend` struct to initialize.
* @param version Version the struct; pass `GIT_ODB_BACKEND_VERSION`
* @return Zero on success; -1 on failure.
*/
GIT_EXTERN(int) git_odb_init_backend(
git_odb_backend *backend,
unsigned int version);
/**
* Allocate data for an ODB object. Custom ODB backends may use this
* to provide data back to the ODB from their read function. This
* memory should not be freed once it is returned to libgit2. If a
* custom ODB uses this function but encounters an error and does not
* return this data to libgit2, then they should use the corresponding
* git_odb_backend_data_free function.
*
* @param backend the ODB backend that is allocating this memory
* @param len the number of bytes to allocate
* @return the allocated buffer on success or NULL if out of memory
*/
GIT_EXTERN(void *) git_odb_backend_data_alloc(git_odb_backend *backend, size_t len);
/**
* Frees custom allocated ODB data. This should only be called when
* memory allocated using git_odb_backend_data_alloc is not returned
* to libgit2 because the backend encountered an error in the read
* function after allocation and did not return this data to libgit2.
*
* @param backend the ODB backend that is freeing this memory
* @param data the buffer to free
*/
GIT_EXTERN(void) git_odb_backend_data_free(git_odb_backend *backend, void *data);
/*
* Users can avoid deprecated functions by defining `GIT_DEPRECATE_HARD`.
*/
#ifndef GIT_DEPRECATE_HARD
/**
* Allocate memory for an ODB object from a custom backend. This is
* an alias of `git_odb_backend_data_alloc` and is preserved for
* backward compatibility.
*
* This function is deprecated, but there is no plan to remove this
* function at this time.
*
* @deprecated git_odb_backend_data_alloc
* @see git_odb_backend_data_alloc
*/
GIT_EXTERN(void *) git_odb_backend_malloc(git_odb_backend *backend, size_t len);
#endif
GIT_END_DECL
#endif
|
