blob: 6f032a1fe2181232b2ee2cbfef3443ce7d86d45d (
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
|
/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkMessageBus_DEFINED
#define SkMessageBus_DEFINED
#include "SkLazyPtr.h"
#include "SkMutex.h"
#include "SkTArray.h"
#include "SkTDArray.h"
#include "SkTypes.h"
template <typename Message>
class SkMessageBus : SkNoncopyable {
public:
// Post a message to be received by all Inboxes for this Message type. Threadsafe.
static void Post(const Message& m);
class Inbox {
public:
Inbox();
~Inbox();
// Overwrite out with all the messages we've received since the last call. Threadsafe.
void poll(SkTArray<Message>* out);
private:
SkTArray<Message> fMessages;
SkMutex fMessagesMutex;
friend class SkMessageBus;
void receive(const Message& m); // SkMessageBus is a friend only to call this.
};
private:
SkMessageBus();
static SkMessageBus* Get();
// Allow SkLazyPtr to call SkMessageBus::SkMessageBus().
template <typename T> friend T* Private::sk_new();
SkTDArray<Inbox*> fInboxes;
SkMutex fInboxesMutex;
};
// This must go in a single .cpp file, not some .h, or we risk creating more than one global
// SkMessageBus per type when using shared libraries. NOTE: at most one per file will compile.
#define DECLARE_SKMESSAGEBUS_MESSAGE(Message) \
SK_DECLARE_STATIC_LAZY_PTR(SkMessageBus<Message>, bus); \
template <> \
SkMessageBus<Message>* SkMessageBus<Message>::Get() { \
return bus.get(); \
}
// ----------------------- Implementation of SkMessageBus::Inbox -----------------------
template<typename Message>
SkMessageBus<Message>::Inbox::Inbox() {
// Register ourselves with the corresponding message bus.
SkMessageBus<Message>* bus = SkMessageBus<Message>::Get();
SkAutoMutexAcquire lock(bus->fInboxesMutex);
bus->fInboxes.push(this);
}
template<typename Message>
SkMessageBus<Message>::Inbox::~Inbox() {
// Remove ourselves from the corresponding message bus.
SkMessageBus<Message>* bus = SkMessageBus<Message>::Get();
SkAutoMutexAcquire lock(bus->fInboxesMutex);
// This is a cheaper fInboxes.remove(fInboxes.find(this)) when order doesn't matter.
for (int i = 0; i < bus->fInboxes.count(); i++) {
if (this == bus->fInboxes[i]) {
bus->fInboxes.removeShuffle(i);
break;
}
}
}
template<typename Message>
void SkMessageBus<Message>::Inbox::receive(const Message& m) {
SkAutoMutexAcquire lock(fMessagesMutex);
fMessages.push_back(m);
}
template<typename Message>
void SkMessageBus<Message>::Inbox::poll(SkTArray<Message>* messages) {
SkASSERT(messages);
messages->reset();
SkAutoMutexAcquire lock(fMessagesMutex);
fMessages.swap(messages);
}
// ----------------------- Implementation of SkMessageBus -----------------------
template <typename Message>
SkMessageBus<Message>::SkMessageBus() {}
template <typename Message>
/*static*/ void SkMessageBus<Message>::Post(const Message& m) {
SkMessageBus<Message>* bus = SkMessageBus<Message>::Get();
SkAutoMutexAcquire lock(bus->fInboxesMutex);
for (int i = 0; i < bus->fInboxes.count(); i++) {
bus->fInboxes[i]->receive(m);
}
}
#endif // SkMessageBus_DEFINED
|
