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
|
// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_SHAREDPTR_REGISTRY_H
#define CEPH_SHAREDPTR_REGISTRY_H
#include <map>
#include <memory>
#include "common/Mutex.h"
#include "common/Cond.h"
/**
* Provides a registry of shared_ptr<V> indexed by K while
* the references are alive.
*/
template <class K, class V>
class SharedPtrRegistry {
Mutex lock;
Cond cond;
typedef std::tr1::shared_ptr<V> VPtr;
typedef std::tr1::weak_ptr<V> WeakVPtr;
map<K, WeakVPtr> contents;
class OnRemoval {
SharedPtrRegistry<K,V> *parent;
K key;
public:
OnRemoval(SharedPtrRegistry<K,V> *parent, K key) :
parent(parent), key(key) {}
void operator()(V *to_remove) {
{
Mutex::Locker l(parent->lock);
parent->contents.erase(key);
parent->cond.Signal();
}
delete to_remove;
}
};
friend class OnRemoval;
public:
SharedPtrRegistry() : lock("SharedPtrRegistry::lock") {}
VPtr lookup(const K &key) {
Mutex::Locker l(lock);
while (1) {
if (contents.count(key)) {
VPtr retval = contents[key].lock();
if (retval)
return retval;
} else {
break;
}
cond.Wait(lock);
Mutex::Locker l(lock);
}
return VPtr();
}
VPtr lookup_or_create(const K &key) {
Mutex::Locker l(lock);
while (1) {
if (contents.count(key)) {
VPtr retval = contents[key].lock();
if (retval)
return retval;
} else {
break;
}
cond.Wait(lock);
}
VPtr retval(new V(), OnRemoval(this, key));
contents[key] = retval;
return retval;
}
template<class A>
VPtr lookup_or_create(const K &key, const A &arg) {
Mutex::Locker l(lock);
while (1) {
if (contents.count(key)) {
VPtr retval = contents[key].lock();
if (retval)
return retval;
} else {
break;
}
cond.Wait(lock);
}
VPtr retval(new V(arg), OnRemoval(this, key));
contents[key] = retval;
return retval;
}
};
#endif
|
