1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkMessageBus.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,116 @@
1.4 +/*
1.5 + * Copyright 2013 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef SkMessageBus_DEFINED
1.12 +#define SkMessageBus_DEFINED
1.13 +
1.14 +#include "SkOnce.h"
1.15 +#include "SkTDArray.h"
1.16 +#include "SkThread.h"
1.17 +#include "SkTypes.h"
1.18 +
1.19 +template <typename Message>
1.20 +class SkMessageBus : SkNoncopyable {
1.21 +public:
1.22 + // Post a message to be received by all Inboxes for this Message type. Threadsafe.
1.23 + static void Post(const Message& m);
1.24 +
1.25 + class Inbox {
1.26 + public:
1.27 + Inbox();
1.28 + ~Inbox();
1.29 +
1.30 + // Overwrite out with all the messages we've received since the last call. Threadsafe.
1.31 + void poll(SkTDArray<Message>* out);
1.32 +
1.33 + private:
1.34 + SkTDArray<Message> fMessages;
1.35 + SkMutex fMessagesMutex;
1.36 +
1.37 + friend class SkMessageBus;
1.38 + void receive(const Message& m); // SkMessageBus is a friend only to call this.
1.39 + };
1.40 +
1.41 +private:
1.42 + SkMessageBus();
1.43 + static SkMessageBus* Get();
1.44 + static void New(SkMessageBus**);
1.45 +
1.46 + SkTDArray<Inbox*> fInboxes;
1.47 + SkMutex fInboxesMutex;
1.48 +};
1.49 +
1.50 +// This must go in a single .cpp file, not some .h, or we risk creating more than one global
1.51 +// SkMessageBus per type when using shared libraries.
1.52 +#define DECLARE_SKMESSAGEBUS_MESSAGE(Message) \
1.53 + template <> \
1.54 + SkMessageBus<Message>* SkMessageBus<Message>::Get() { \
1.55 + static SkMessageBus<Message>* bus = NULL; \
1.56 + SK_DECLARE_STATIC_ONCE(once); \
1.57 + SkOnce(&once, &New, &bus); \
1.58 + SkASSERT(bus != NULL); \
1.59 + return bus; \
1.60 + }
1.61 +
1.62 +// ----------------------- Implementation of SkMessageBus::Inbox -----------------------
1.63 +
1.64 +template<typename Message>
1.65 +SkMessageBus<Message>::Inbox::Inbox() {
1.66 + // Register ourselves with the corresponding message bus.
1.67 + SkMessageBus<Message>* bus = SkMessageBus<Message>::Get();
1.68 + SkAutoMutexAcquire lock(bus->fInboxesMutex);
1.69 + bus->fInboxes.push(this);
1.70 +}
1.71 +
1.72 +template<typename Message>
1.73 +SkMessageBus<Message>::Inbox::~Inbox() {
1.74 + // Remove ourselves from the corresponding message bus.
1.75 + SkMessageBus<Message>* bus = SkMessageBus<Message>::Get();
1.76 + SkAutoMutexAcquire lock(bus->fInboxesMutex);
1.77 + // This is a cheaper fInboxes.remove(fInboxes.find(this)) when order doesn't matter.
1.78 + for (int i = 0; i < bus->fInboxes.count(); i++) {
1.79 + if (this == bus->fInboxes[i]) {
1.80 + bus->fInboxes.removeShuffle(i);
1.81 + break;
1.82 + }
1.83 + }
1.84 +}
1.85 +
1.86 +template<typename Message>
1.87 +void SkMessageBus<Message>::Inbox::receive(const Message& m) {
1.88 + SkAutoMutexAcquire lock(fMessagesMutex);
1.89 + fMessages.push(m);
1.90 +}
1.91 +
1.92 +template<typename Message>
1.93 +void SkMessageBus<Message>::Inbox::poll(SkTDArray<Message>* messages) {
1.94 + SkASSERT(NULL != messages);
1.95 + messages->reset();
1.96 + SkAutoMutexAcquire lock(fMessagesMutex);
1.97 + messages->swap(fMessages);
1.98 +}
1.99 +
1.100 +// ----------------------- Implementation of SkMessageBus -----------------------
1.101 +
1.102 +template <typename Message>
1.103 +SkMessageBus<Message>::SkMessageBus() {}
1.104 +
1.105 +template <typename Message>
1.106 +/*static*/ void SkMessageBus<Message>::New(SkMessageBus<Message>** bus) {
1.107 + *bus = new SkMessageBus<Message>();
1.108 +}
1.109 +
1.110 +template <typename Message>
1.111 +/*static*/ void SkMessageBus<Message>::Post(const Message& m) {
1.112 + SkMessageBus<Message>* bus = SkMessageBus<Message>::Get();
1.113 + SkAutoMutexAcquire lock(bus->fInboxesMutex);
1.114 + for (int i = 0; i < bus->fInboxes.count(); i++) {
1.115 + bus->fInboxes[i]->receive(m);
1.116 + }
1.117 +}
1.118 +
1.119 +#endif // SkMessageBus_DEFINED
