cthread.h

研读AxCrypt对加解密的处理方法

#pragma once
#ifndef AXPIPE_CTHREAD_H
#define AXPIPE_CTHREAD_H
/*! \file CThread.h
    \brief Threading dummy base and template wrapper AxPipe::CNoThread and AxPipe::CThread<>

    @(#) $Id: CThread.h,v 1.2 2004/01/01 20:05:54 svante Exp $

    AxPipe - Binary Stream Framework

    Copyright (C) 2003 Svante Seleborg/Axon Data, All rights reserved.

    This program is free software; you can redistribute it and/or modify it under the terms
    of the GNU General Public License as published by the Free Software Foundation;
    either version 2 of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
    without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along with this program;
    if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
    Boston, MA 02111-1307 USA

    The author may be reached at mailto:[e-mail] and http://axpipe.sourceforge.net

    Why is this framework released as GPL and not LGPL?
    See http://www.gnu.org/philosophy/why-not-lgpl.html

----
\verbatim
    CThread.h                       Threading dummy base and template wrapper

    E-mail                          YYYY-MM-DD              Reason
    [e-mail]              2003-12-05              Initial
\endverbatim
*/
#include "AxPipe.h"

#include "AxAssert.h"
#define AXLIB_ASSERT_FILE "CThread.h"

namespace AxPipe {
    using AxLib::OutputDebugStringF;

/// \brief Dummy non-threaded base-class for all CSource, CSink and CPipe derived classes.
/// \see CSource
/// \see CSink
/// \see CPipe
/// \see CThread
///
/// Mostly placeholders in the case we later derive from CThread, in which case the virtuals
/// here get overridden with real thread-handling and synchronizating functionality. Some
/// basic code that is common is defined here.
class CNoThread {
protected:
    bool m_fExit;                           ///< Set to true when the derived object is to exit.
    bool m_fAutoDeleteSink;                 ///< Set to true if the derived object's sink is to self-destruct with the pipe-line.
    
    /// \brief Initalize one Work-cycle, processing one CSeg.
    virtual void WorkStart() {              
    }
    /// \brief Start Work() on one CSeg.
    virtual void WorkSignal() {
        Work();
    }
    /// \brief End one Work-cycle.
    virtual void WorkEnd() {
    }
    /// \brief Wait for a new CSeg to arrive to work on.
    virtual void WorkWait() {
    }
    /// \brief Wait for the Work()-thread, if any, to terminate.
    virtual void WorkExitWait() {
    }
    /// \brief Actually process one CSeg.
    virtual void Work() = 0;
public:
    CNoThread() {
        m_fAutoDeleteSink = m_fExit = false;
    }
    /// \brief Wait for the Work() thread to finish if it's processing.
    ///
    /// Defined here, but only has function in threaded version.
    /// Start and End one Work cycle, thereby ensuring that the
    /// previous one has finished.
    void WaitForIdle() {
        WorkStart();
        WorkEnd();
    }
    /// \brief Run-time type identifcation.
    ///
    /// We're not using the built in RTTI because we sometimes want to be able
    /// to forego most of the run time library, as well as exceptions and RTTI.
    ///
    /// The point here is to create a guaranteed unique value that is the same
    /// for all instances of a class, while not requiring any inits outside
    /// of the class declaration, and also to 'fool' optimizing compilers, so
    /// that they cannot perform global optimization and figure out that it can
    /// fold identical functions into one. It happened in a previous version...
    /// That's why we include the static int, it can't be optimized away, at least
    /// not easily.
    /// You need to override ClassId() and RTClassId() in all derived clases you
    /// want to distinguish, this is
    /// most easily done by simply copying and pasting exactly these definitions.
    /// There is also the Run-Time version, accessible through a pointer to a
    /// polymorphic base-class for example, RTClassId().
    static void *ClassId() {
        static int i;
        return &i;
    }

    /// \brief Run-Time version of our type identification.
    /// \see ClassId()
    virtual void *RTClassId() {
        return ClassId();
    }
};

/// \brief Only used as a ThreadProc to get back into the class.
/// \param lpParam The 'this' pointer of the class where this is run.
//static inline DWORD WINAPI CThreadProc(LPVOID lpParam);

#pragma warning (push)
// Disable 'this' : used in base member initializer list
#pragma warning (disable: 4355)
/// \brief Template to implement a pipe-section in a separate thread.
///
/// The basic thread mechanism revolves around a number of virtual
/// functions that are overriden here, such as
/// Work(). All synchronization etc is handled by the class, and
/// the Work() function is called in it's own thread.
///
/// To enable threading use the appropriate CSource, CPipe or CSink derived
/// class as the argument.
/// \param T A CSource, CPipe or CSink derived class to run in a separate thread.
template <class T> class CThreadNoRun : public CThreadMain<T> {
    CThreadSync m_ThreadSync;               ///< Implement worker thread synchronization.

public:
    
    /// \brief Wait for the worker thread to terminate, then close handles etc.
    virtual ~CThreadNoRun() {
        if (!m_fExit) {
            SetError(ERROR_CODE_INTERNAL, ERROR_MSG_INTERNAL, _T("CThread::~CThread Exit() not called"));
        }
    }

public:
    /// \brief Initiate one Work() cycle - called from outside worker thread.
    void WorkStart() {
        m_ThreadSync.WorkStart();
    }

    /// \brief Signal that we've prepared for more Work() - called from outside worker thread.
    void WorkSignal() {
        m_ThreadSync.WorkSignal();
    }
    
    /// \brief Wait for more to be ready for Work() - this is called in the worker thread.
    void WorkWait() {
        m_ThreadSync.WorkWait();
    }
    
    /// \brief End one Work() cycle - called from the worker thread.
    void WorkEnd() {
        m_ThreadSync.WorkEnd();
    }
    
    /// \brief Wait for the Work()-thread, if any, to terminate.
    virtual void WorkExitWait() {
        Wait();
    }
};

/// \brief Thread wrapper for AxPipe CSource, CPipe and CSink derived classes.
///
/// Setup a thread, start it running and pump data through the Work() member
/// function, using thread synchronization. Basically all Out* and In* functions
/// will run in the context of this separate thread.
template <class T> class CThread : public CThreadNoRun<T> {
public:
    CThread() {
        Run();
    }
private:
    /// \brief The ThreadProc for the worker thread
    /// \return Always 0, not the thread exit code.
    virtual int Main() {
        OutputDebugStringF(_T("CThread()::Main() ID=%X\n"), GetCurrentThreadId());
        while (!m_fExit) {
            // Elesewhere WorkStart() and WorkSignal() will be called
            WorkWait();                     // Wait for more to do
            Work();
            WorkEnd();
        }
        OutputDebugStringF(_T("CThread()::Main() ID=%X WaitForIdle()...\n"), GetCurrentThreadId());
        WaitForIdle();                      // Ensure that the last work is done.
        // This is to handle a memory leak bug in Win32, where an exiting
        // thread being a fibre does not clean up after itself. See Q185231 or KB185231.
		// Update 2005-05-20: And the really, really great thing is they fixed the bug in Windows Server 2003,
		// causing the delete by the system to result in a double free on the heap and making the program
		// crash! So the fix breaks the documented work-around - and there is no documented way to determine
		// if the fix is in or not! Aaaaarghhhh. What to do? We let the memory leak.
		//
        // If we have successfully allocated a TLS index
        if (AxPipe::dwTlsIndex != TLS_OUT_OF_INDEXES) {
            // If we have converted this thread into a fiber
            if (TlsGetValue(AxPipe::dwTlsIndex) != NULL) {
                // Then we do the free to avoid the memory leak as per above.
				//See above! ::LocalFree(GetCurrentFiber());
            }
        }
        OutputDebugStringF(_T("CThread()::Main() ...exiting thread ID=%X\n"), GetCurrentThreadId());
        return 0;
    }

};

/// \brief Start a CSource in a separate thread.
/// A CSource derived class will be setup to Drain() in
/// it's own thread.
/// \see Main()
/// \param T A CSource derived class to start in it's own thread.
template <class T> class CThreadSource : public CThreadMain<T> {
private:
    /// \brief The ThreadProc for the worker thread
    /// Do Open()->Drain()->Close()->Plug();
    /// \return Always 0, not the thread exit code.
    virtual int Main() {
        Open()->Drain()->Close()->Plug();
        return 0;
    }
};

#pragma warning (pop)

}; // namespace AxPipe
#endif AXPIPE_CTHREAD_H