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|
/* +------------------------------------+
* | Inspire Internet Relay Chat Daemon |
* +------------------------------------+
*
* InspIRCd: (C) 2002-2008 InspIRCd Development Team
* See: http://www.inspircd.org/wiki/index.php/Credits
*
* This program is free but copyrighted software; see
* the file COPYING for details.
*
* ---------------------------------------------------
*/
#ifndef __THREADENGINE__
#define __THREADENGINE__
#include <vector>
#include <string>
#include <map>
#include "inspircd_config.h"
#include "base.h"
class InspIRCd;
class Thread;
/** The ThreadEngine class has the responsibility of initialising
* Thread derived classes. It does this by creating operating system
* level threads which are then associated with the class transparently.
* This allows Thread classes to be derived without needing to know how
* the OS implements threads. You should ensure that any sections of code
* that use threads are threadsafe and do not interact with any other
* parts of the code which are NOT known threadsafe! If you really MUST
* access non-threadsafe code from a Thread, use the Mutex class to wrap
* access to the code carefully.
*/
class CoreExport ThreadEngine : public Extensible
{
protected:
/** Creator instance
*/
InspIRCd* ServerInstance;
/** New Thread being created.
*/
Thread* NewThread;
public:
/** Constructor.
* @param Instance Creator object
*/
ThreadEngine(InspIRCd* Instance);
/** Destructor
*/
virtual ~ThreadEngine();
/** Enable or disable system-wide mutex for threading.
* Remember that if you toggle the mutex you MUST UNSET
* IT LATER otherwise the program will DEADLOCK!
* It is recommended that you AVOID USE OF THIS METHOD
* and use your own Mutex class, this function is mainly
* reserved for use by the core and by the Thread engine
* itself.
* @param enable True to lock the mutex.
*/
virtual bool Mutex(bool enable) = 0;
/** Run the newly created thread.
*/
virtual void Run() = 0;
/** Create a new thread. This takes an already allocated
* Thread* pointer and initializes it to use this threading
* engine. On failure, this function may throw a CoreException.
* @param thread_to_init Pointer to a newly allocated Thread
* derived object.
*/
virtual void Create(Thread* thread_to_init) = 0;
/** This is called by the default destructor of the Thread
* class to ensure that the thread engine which created the thread
* is responsible for destroying it.
* @param thread Existing and active thread to delete.
*/
virtual void FreeThread(Thread* thread) = 0;
/** Returns the thread engine's name for display purposes
* @return The thread engine name
*/
virtual const std::string GetName()
{
return "<pure-virtual>";
}
};
/** The Mutex class represents a mutex, which can be used to keep threads
* properly synchronised. Use mutexes sparingly, as they are a good source
* of thread deadlocks etc, and should be avoided except where absolutely
* neccessary. Note that the internal behaviour of the mutex varies from OS
* to OS depending on the thread engine, for example in windows a Mutex
* in InspIRCd uses critical sections, as they are faster and simpler to
* manage.
*/
class CoreExport Mutex : public Extensible
{
protected:
/** Creator object
*/
InspIRCd* ServerInstance;
/** Enable or disable the Mutex. This method has somewhat confusing
* wording (e.g. the function name and parameters) so it is protected
* in preference of the Lock() and Unlock() methods which are user-
* accessible.
*
* @param enable True to enable the mutex (enter it) and false to
* disable the mutex (leave it).
*/
virtual void Enable(bool enable) = 0;
public:
/** Constructor.
* @param Instance Creator object
*/
Mutex(InspIRCd* Instance);
/** Enter/enable the mutex lock.
*/
void Lock() { Enable(true); }
/** Leave/disable the mutex lock.
*/
void Unlock() { Enable(false); }
/** Destructor
*/
~Mutex() { }
};
/** Derive from this class to implement your own threaded sections of
* code. Be sure to keep your code thread-safe and not prone to deadlocks
* and race conditions if you MUST use threading!
*/
class CoreExport Thread : public Extensible
{
private:
/** Set to true when the thread is to exit
*/
bool ExitFlag;
public:
/** Creator thread engine
*/
ThreadEngine* Creator;
/** Set Creator to NULL at this point
*/
Thread() : ExitFlag(false), Creator(NULL)
{
}
/** If this thread has a Creator set, call it to
* free the thread
*/
virtual ~Thread()
{
if (Creator)
Creator->FreeThread(this);
}
/** Override this method to put your actual
* threaded code here.
*/
virtual void Run() = 0;
/** Signal the thread to exit gracefully.
*/
void SetExitFlag()
{
ExitFlag = true;
}
/** Cancel an exit state.
*/
void ClearExitFlag()
{
ExitFlag = false;
}
/** Get thread's current exit status.
* (are we being asked to exit?)
*/
bool GetExitFlag()
{
return ExitFlag;
}
};
#endif
|
