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// -*- C++ -*-
//=============================================================================
/**
* @file Reactor_Token_T.h
*
* @author Steve Huston <shuston@riverace.com>
*/
//=============================================================================
#ifndef ACE_REACTOR_TOKEN_T_H
#define ACE_REACTOR_TOKEN_T_H
#include /**/ "ace/pre.h"
#include "ace/Reactor_Impl.h"
#include "ace/Token.h"
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
/**
* @class ACE_Reactor_Token_T
*
* @internal For ACE internal use only.
*
* @brief Used as a synchronization mechanism to coordinate concurrent
* access to an ACE_Reactor_Impl object.
*
* This class is used to make access to a reactor's internals and
* demultiplexing mechanism thread-safe. By default, the thread that
* runs the handle_events() loop holds the token, even when it is blocked
* in the demultiplexer. Whenever another thread wants to access the
* reactor, such as via the register_handler(), remove_handler(), etc.
* methods, it must ask the token owner for temporary release of the token.
* To accomplish this, this class reimplements the ACE_Token::sleep_hook()
* method through which the owning thread can be notified to temporarily
* release the token if the current situation permits.
*
* The owner of the token is responsible for deciding which
* request for the token can be granted. By using the
* ACE_Token::renew() method, the thread that releases the token
* temporarily can specify to get the token back right after the
* other thread has completed using the token. Thus, there is a
* dedicated thread that owns the token by default. This
* thread grants other threads access to the token by ensuring
* that whenever somebody else has finished using the token the
* original owner reclaims the token again, i.e., the owner has the
* chance to schedule other threads. The thread that most likely needs
* the token most of the time is the thread running the dispatch loop.
*/
template <class ACE_TOKEN_TYPE>
class ACE_Reactor_Token_T : public ACE_TOKEN_TYPE
{
public:
ACE_Reactor_Token_T (ACE_Reactor_Impl &r,
int s_queue = ACE_TOKEN_TYPE::FIFO);
ACE_Reactor_Token_T (int s_queue = ACE_TOKEN_TYPE::FIFO);
virtual ~ACE_Reactor_Token_T (void);
/// Called just before a token waiter goes to sleep.
/// @see ACE_Token::sleep_hook
virtual void sleep_hook (void);
/// Get the reactor implementation
ACE_Reactor_Impl &reactor (void);
/// Set the reactor implementation
void reactor (ACE_Reactor_Impl &);
/// Dump the state of an object.
virtual void dump () const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
private:
ACE_Reactor_Impl *reactor_;
};
ACE_END_VERSIONED_NAMESPACE_DECL
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Reactor_Token_T.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("Reactor_Token_T.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#include /**/ "ace/post.h"
#endif /* ACE_REACTOR_TOKEN_T_H */
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