summaryrefslogtreecommitdiff
path: root/src/mongo/base/init.h
blob: 1d6595592aaeb92f9f523e0b20b69776435ff62a (plain)
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
/*    Copyright 2012 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

/**
 * Utility macros for declaring global initializers
 *
 * Should NOT be included by other header files.  Include only in source files.
 *
 * Initializers are arranged in an acyclic directed dependency graph.  Declaring
 * a cycle will lead to a runtime error.
 *
 * Initializer functions take a parameter of type ::mongo::InitializerContext*, and return
 * a Status.  Any status other than Status::OK() is considered a failure that will stop further
 * intializer processing.
 */

#pragma once

#include "mongo/base/deinitializer_context.h"
#include "mongo/base/global_initializer.h"
#include "mongo/base/global_initializer_registerer.h"
#include "mongo/base/initializer.h"
#include "mongo/base/initializer_context.h"
#include "mongo/base/initializer_function.h"
#include "mongo/base/make_string_vector.h"
#include "mongo/base/status.h"

/**
 * Convenience parameter representing an empty set of prerequisites for an initializer function.
 */
#define MONGO_NO_PREREQUISITES (NULL)

/**
 * Convenience parameter representing an empty set of dependents of an initializer function.
 */
#define MONGO_NO_DEPENDENTS (NULL)

/**
 * Convenience parameter representing the default set of dependents for initializer functions.
 */
#define MONGO_DEFAULT_PREREQUISITES (MONGO_DEFAULT_PREREQUISITES_STR)

/**
 * Macro to define an initializer function named "NAME" with the default prerequisites, and
 * no explicit dependents.
 *
 * See MONGO_INITIALIZER_GENERAL.
 *
 * Usage:
 *     MONGO_INITIALIZER(myModule)(::mongo::InitializerContext* context) {
 *         ...
 *     }
 */
#define MONGO_INITIALIZER(NAME) \
    MONGO_INITIALIZER_WITH_PREREQUISITES(NAME, MONGO_DEFAULT_PREREQUISITES)

/**
 * Macro to define an initializer function named "NAME" that depends on the initializers
 * specified in PREREQUISITES to have been completed, but names no explicit dependents.
 *
 * See MONGO_INITIALIZER_GENERAL.
 *
 * Usage:
 *     MONGO_INITIALIZER_WITH_PREREQUISITES(myGlobalStateChecker,
 *                                         ("globalStateInitialized", "stacktraces"))(
 *            ::mongo::InitializerContext* context) {
 *    }
 */
#define MONGO_INITIALIZER_WITH_PREREQUISITES(NAME, PREREQUISITES) \
    MONGO_INITIALIZER_GENERAL(NAME, PREREQUISITES, MONGO_NO_DEPENDENTS)

/**
 * Macro to define an initializer that depends on PREREQUISITES and has DEPENDENTS as explicit
 * dependents.
 *
 * NAME is any legitimate name for a C++ symbol.
 * PREREQUISITES is a tuple of 0 or more std::string literals, i.e., ("a", "b", "c"), or ()
 * DEPENDENTS is a tuple of 0 or more std::string literals.
 *
 * At run time, the full set of prerequisites for NAME will be computed as the union of the
 * explicit PREREQUISITES and the set of all other mongo initializers that name NAME in their
 * list of dependents.
 *
 * Usage:
 *    MONGO_INITIALIZER_GENERAL(myInitializer,
 *                             ("myPrereq1", "myPrereq2", ...),
 *                             ("myDependent1", "myDependent2", ...))(
 *            ::mongo::InitializerContext* context) {
 *    }
 *
 * TODO: May want to be able to name the initializer separately from the function name.
 * A form that takes an existing function or that lets the programmer supply the name
 * of the function to declare would be options.
 */
#define MONGO_INITIALIZER_GENERAL(NAME, PREREQUISITES, DEPENDENTS)                        \
    ::mongo::Status _MONGO_INITIALIZER_FUNCTION_NAME(NAME)(::mongo::InitializerContext*); \
    namespace {                                                                           \
    ::mongo::GlobalInitializerRegisterer _mongoInitializerRegisterer_##NAME(              \
        std::string(#NAME),                                                               \
        MONGO_MAKE_STRING_VECTOR PREREQUISITES,                                           \
        MONGO_MAKE_STRING_VECTOR DEPENDENTS,                                              \
        mongo::InitializerFunction(_MONGO_INITIALIZER_FUNCTION_NAME(NAME)));              \
    }                                                                                     \
    ::mongo::Status _MONGO_INITIALIZER_FUNCTION_NAME(NAME)

/**
 * Macro to define an initializer group.
 *
 * An initializer group is an initializer that performs no actions.  It is useful for organizing
 * initialization steps into phases, such as "all global parameter declarations completed", "all
 * global parameters initialized".
 */
#define MONGO_INITIALIZER_GROUP(NAME, PREREQUISITES, DEPENDENTS)                               \
    MONGO_INITIALIZER_GENERAL(NAME, PREREQUISITES, DEPENDENTS)(::mongo::InitializerContext*) { \
        return ::mongo::Status::OK();                                                          \
    }

/**
 * Macro to produce a name for a mongo initializer function for an initializer operation
 * named "NAME".
 */
#define _MONGO_INITIALIZER_FUNCTION_NAME(NAME) _mongoInitializerFunction_##NAME