ReadableFile.h

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//==============================================================================================
//  FILENAME    :   ReadableFile.h
//  AUTHOR      :   vovechkin
//  CREATION    :   2004-09-28
//  Copyright (C) MicroStrategy Incorporated 2004
//  All Rights Reserved
//==============================================================================================
#ifndef MFileSystem_ReadableFile_h
#define MFileSystem_ReadableFile_h

#include "Base/Base/Timer.h"

#include "FileSystem.h" // for FILE_SYSTEM_DLL_EXPORT

#include "GenericFile.h"

namespace MDataType
{
    // forward declarations
    class Binary;
}

namespace MFileSystem
{
    class ReadableFile:
        virtual public GenericFile
    {
    public:

        typedef MBase::StrongPtr<ReadableFile> Ptr;
        typedef MBase::ReturnPtr<ReadableFile> ReturnPtr;

        // virtual destructor is a must
        virtual ~ReadableFile() throw()
        {
        }

        virtual void Read(void* ipBuffer, size_t iBufferSize) = 0;

        virtual void Read(MDataType::Binary& irBinary, size_t iMaxSize = 0) = 0;

        virtual void ReadLittleEndian(unsigned Int32& orValue) = 0;

        virtual void ReadLine(MDataType::Binary& irBinary) = 0;

        virtual const MBase::TotalTimer& GetReadTimer() const = 0;

        virtual const MBase::TotalTimer& GetReadLockTimer() const = 0;

        class DLL_FILE_SYSTEM_EXIM ReadSmartLock
        {
        public:

            ReadSmartLock(ReadableFile& irReadableFile);
            ~ReadSmartLock() throw();

            void Unlock() throw();

        protected:

            ReadSmartLock();

            ReadableFile* mpReadableFile;
            bool mIsLocked;
        };

        class DLL_FILE_SYSTEM_EXIM ReadSmartLock_NoWait:
            public ReadSmartLock
        {
        public:

            ReadSmartLock_NoWait(ReadableFile& irReadableFile);

            bool IsLocked() const throw()
            {
                return mIsLocked;
            }
        };

    protected:

        friend class ReadSmartLock;
        friend class ReadSmartLock_NoWait;

        virtual bool ReadLock(bool iNoWait) = 0;
        virtual void ReadUnlock() throw() = 0;
    };
    
    DLL_FILE_SYSTEM_EXIM ReadableFile::ReturnPtr OpenReadableFile(const char* ipPath);

    DLL_FILE_SYSTEM_EXIM ReadableFile::ReturnPtr OpenReadableFile_InProcessLockNoWait(const char* ipPath);
}

#endif // MFileSystem_ReadableFile_h