123 lines
3.2 KiB
C
123 lines
3.2 KiB
C
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//+----------------------------------------------------------------------------
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//
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// Copyright (C) 1997, Microsoft Corporation
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//
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// File: thrdpool.h
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//
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// Contents: definitions needed for clients of the thrdpool lib
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//
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// Description: The thrdpool library defines the CWorkerThread base class
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// Users of this lib should define their own derived class
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// that inherits from CWorkerThread. Each CWorkerThread object
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// has a thread that is used to do some work. It is also
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// associated with a common completion port that is used to
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// queue work items. All worker threads will normally block on
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// GetQueuedCompletionStatus(). Clients of the CWorkerThread
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// objects will call PostWork() to get work done. This will
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// result in one of the worker threads returning from
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// GetQueuedCompletionStatus() and calling the derived class'
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// WorkCompletion() routine with a pvContext.
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//
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// NOTE: the base class has no knowledge of the type of work
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// getting done. It just manages the details of getting work
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// requests and distributing it to threads in its pool. This
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// allows the derived class to focus on processing the actual
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// work item without bothering about queueing etc.
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//
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// Completion ports are used merely to leverage its queueing
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// semantics and not for I/O. If the work done by each thread
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// is fairly small, LIFO semantics of completion ports will
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// reduce context switches.
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//
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// Functions:
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//
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// History: 03/15/97 Rajeev Rajan (rajeevr) Created
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//
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//-----------------------------------------------------------------------------
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#ifndef THRDPOOL_H
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#define THRDPOOL_H
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//
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// This is the blob that is passed thro the completion port
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//
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typedef struct _WorkContextEnv
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{
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OVERLAPPED Ov; // needed by Post/GetQueuedCompletionStatus
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PVOID pvWorkContext; // actual work context - user defined
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} WorkContextEnv, *LPWorkContextEnv;
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//
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// Base worker thread class
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//
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class CWorkerThread
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{
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public:
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//
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// Constructor, destructor
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//
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CWorkerThread();
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virtual ~CWorkerThread();
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//
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// class initializer - should be called once before this class is used
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//
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static BOOL InitClass( DWORD dwConcurrency );
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//
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// class terminator - should be called once when done using the class
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//
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static BOOL TermClass();
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//
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// clients should call this to post work items
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//
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BOOL PostWork(PVOID pvWorkContext);
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//
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// expose shutdown event
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//
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HANDLE QueryShutdownEvent() { return m_hShutdownEvent; }
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protected:
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//
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// derived method called when work items are posted
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//
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virtual VOID WorkCompletion(PVOID pvWorkContext) = 0;
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private:
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//
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// check for matching InitClass(), TermClass() calls
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//
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static LONG m_lInitCount;
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//
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// handle to completion port
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//
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static HANDLE m_hCompletionPort;
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//
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// handle to worker thread
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//
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HANDLE m_hThread;
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//
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// shutdown event
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//
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HANDLE m_hShutdownEvent;
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//
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// thread function
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//
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static DWORD __stdcall ThreadDispatcher(PVOID pvWorkerThread);
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//
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// block on GetQueuedCompletionStatus for work items
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//
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VOID GetWorkCompletion(VOID);
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};
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#endif // #ifndef THRDPOOL_H
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