chromium/third_party/skia/src/core/SkMessageBus.h

/*
 * 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 <type_traits>

#include "include/core/SkRefCnt.h"
#include "include/core/SkTypes.h"
#include "include/private/base/SkMutex.h"
#include "include/private/base/SkNoncopyable.h"
#include "include/private/base/SkOnce.h"
#include "include/private/base/SkTArray.h"
#include "include/private/base/SkTDArray.h"

/**
 * The following method must have a specialization for type 'Message':
 *
 *     bool SkShouldPostMessageToBus(const Message&, IDType msgBusUniqueID)
 *
 * We may want to consider providing a default template implementation, to avoid this requirement by
 * sending to all inboxes when the specialization for type 'Message' is not present.
 */
template <typename Message, typename IDType, bool AllowCopyableMessage = true>
class SkMessageBus : SkNoncopyable { … };

// 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, IDType, AllowCopyableMessage) …

//   ----------------------- Implementation of SkMessageBus::Inbox -----------------------

template <typename Message, typename IDType, bool AllowCopyableMessage>
SkMessageBus<Message, IDType, AllowCopyableMessage>::Inbox::Inbox(IDType uniqueID)
        : … { … }

template <typename Message, typename IDType, bool AllowCopyableMessage>
SkMessageBus<Message, IDType, AllowCopyableMessage>::Inbox::~Inbox() { … }

template <typename Message, typename IDType, bool AllowCopyableMessage>
void SkMessageBus<Message, IDType, AllowCopyableMessage>::Inbox::receive(Message m) { … }

template <typename Message, typename IDType, bool AllowCopyableMessage>
void SkMessageBus<Message, IDType, AllowCopyableMessage>::Inbox::poll(
        skia_private::TArray<Message>* messages) { … }

//   ----------------------- Implementation of SkMessageBus -----------------------

template <typename Message, typename IDType, bool AllowCopyableMessage>
SkMessageBus<Message, IDType, AllowCopyableMessage>::SkMessageBus() = default;

template <typename Message, typename IDType, bool AllowCopyableMessage>
/*static*/ void SkMessageBus<Message, IDType, AllowCopyableMessage>::Post(Message m) { … }

#endif  // SkMessageBus_DEFINED