haiku/headers/private/app/DirectMessageTarget.h
Axel Dörfler 9dbe170a69 Implemented direct message passing for local targets; this fixes a deadlock
with PostMessage() in case the message queue is full.
Some notes:
* for synchronous replies, we don't use this mechanism yet, but it could be
  extended to do that as well.
* the code looks so complicated because we need a way to access the looper's
  queue without locking it (to prevent deadlocks); like Dano's solution, I've
  abused BTokenSpace to store a BDirectMessageTarget with a BHandler.
* we also need to decouple the lifetime of a looper's queue from its target,
  as we cannot lock the looper, and therefore, can't guarantee it stays valid
  as long as we're accessing it outside of BLooper.
* init_clipboard() now needs to be done after the global constructors have
  been called - since sending messages now needs gDefaultTokens to be initialized.
  Since this is done per image, it shouldn't cause any troubles, though.
* some minor cleanup, removed unused _msg_cache_cleanup_() and friends.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19968 a95241bf-73f2-0310-859d-f6bbb57e9c96
2007-01-26 13:59:56 +00:00

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/*
* Copyright 2007, Haiku, Inc.
* Distributed under the terms of the MIT License.
*
* Authors:
* Axel Dörfler, axeld@pinc-software.de
*/
#ifndef _DIRECT_MESSAGE_TARGET_H
#define _DIRECT_MESSAGE_TARGET_H
#include <MessageQueue.h>
namespace BPrivate {
class BDirectMessageTarget {
public:
BDirectMessageTarget();
~BDirectMessageTarget();
bool AddMessage(BMessage* message);
void Close();
void Acquire();
void Release();
BMessageQueue* Queue() { return &fQueue; }
private:
int32 fReferenceCount;
BMessageQueue fQueue;
bool fClosed;
};
} // namespace BPrivate
#endif // _DIRECT_MESSAGE_TARGET_H