文件监视在游戏中什么作用？

来自微软的 Donuts

//-----------------------------------------------------------------------------
// File: FileWatch.cpp
//
// Copyright (C) Microsoft Corporation. All Rights Reserved.
//-----------------------------------------------------------------------------
#include "stdafx.h"

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
CFileWatch::CFileWatch()
{
    m_nFilesToWatch         = 0;
    m_hFileChangeThread     = NULL;
    m_dwFileChangeThreadId  = 0;
    m_bFileChanged          = FALSE;
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
CFileWatch::~CFileWatch()
{
    Cleanup();
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
HRESULT CFileWatch::AddFileToWatch( TCHAR* strWatchFile )
{
    strcpy( m_strFilesToWatch[m_nFilesToWatch++], strWatchFile );
    return S_OK;
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
HRESULT CFileWatch::Start()
{
    m_hFileChangeThread = CreateThread( NULL, 0, StaticFileChangeThreadFunc,
                                        this, 0, &m_dwFileChangeThreadId );

    return S_OK;
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
BOOL CFileWatch::HaveFilesChanged( BOOL bResetChangeFlag )
{
    BOOL bFileChanged = m_bFileChanged;

    if( bResetChangeFlag )
        m_bFileChanged = FALSE;

    return bFileChanged;
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
DWORD WINAPI CFileWatch::StaticFileChangeThreadFunc( LPVOID lpParam )
{
    CFileWatch* pApp = (CFileWatch*) lpParam;
    return pApp->FileChangeThreadFunc();
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
DWORD CFileWatch::FileChangeThreadFunc()
{
    HANDLE      hFileHandles[MAX_WATCH_FILES];
    FILETIME    aLastWriteTime[MAX_WATCH_FILES];
    TCHAR       astrFileDir[MAX_WATCH_FILES][MAX_PATH];
    TCHAR*      strFilePart;
    FILETIME    lastWriteTime;
    DWORD       dwResult;
    int         i;
    int         j;
    HANDLE      hWatchHandles[MAX_WATCH_FILES];
    int         nWatchHandles = 0;

    for( i=0; i<m_nFilesToWatch; i++ )
    {
        hFileHandles[i] = CreateFile( m_strFilesToWatch[i], GENERIC_READ,
                                    FILE_SHARE_READ|FILE_SHARE_WRITE,
                                    NULL, OPEN_EXISTING, 0, NULL );
        GetFileTime( hFileHandles[i], NULL, NULL, &aLastWriteTime[i] );
        GetFullPathName( m_strFilesToWatch[i], MAX_PATH,
                         astrFileDir[i], &strFilePart );
        if( strFilePart )
            *strFilePart = 0;

        BOOL bFound = FALSE;
        for( j=0; j<i; j++ )
        {
            if( strcmp( astrFileDir[i], astrFileDir[j] ) == 0 )
            {
                bFound = TRUE;
                break;
            }
        }

        if( !bFound )
        {
            hWatchHandles[nWatchHandles++] = FindFirstChangeNotification(
                                                astrFileDir[i], FALSE,
                                                FILE_NOTIFY_CHANGE_LAST_WRITE );
        }
    }
   
    BOOL bDone = FALSE;
    while( !bDone )
    {  
        dwResult = MsgWaitForMultipleObjects( nWatchHandles, hWatchHandles, FALSE, INFINITE, QS_ALLEVENTS );
        if( dwResult == WAIT_OBJECT_0 + nWatchHandles )
        {
            MSG msg;
            if( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
            {
                if ( msg.message == WM_QUIT )
                    bDone = TRUE;
            }
        }
        else
        {
            int nIndex = dwResult - WAIT_OBJECT_0;
            assert( nIndex >= 0 || nIndex < 10 );

            for( i=0; i<m_nFilesToWatch; i++ )
            {
                GetFileTime( hFileHandles[i], NULL, NULL, &lastWriteTime );
                if( memcmp(&lastWriteTime, &aLastWriteTime[i], sizeof(FILETIME) ) )
                {
                    m_bFileChanged = TRUE;
                }
            }

            FindNextChangeNotification( hWatchHandles[nIndex] );
            FindNextChangeNotification( hWatchHandles[nIndex] );
        }
    }

    for( i=0; i<nWatchHandles; i++ )
        FindCloseChangeNotification( hWatchHandles[i] );

    for( i=0; i<m_nFilesToWatch; i++ )
        CloseHandle( hFileHandles[i] );

    return 0;
}

 

//-----------------------------------------------------------------------------
// Name:
// Desc:
//-----------------------------------------------------------------------------
HRESULT CFileWatch::Cleanup()
{
    if( m_hFileChangeThread )
    {
        PostThreadMessage( m_dwFileChangeThreadId, WM_QUIT, 0, 0 );
        WaitForSingleObject( m_hFileChangeThread, INFINITE );
        CloseHandle( m_hFileChangeThread );
        m_hFileChangeThread = NULL;
    }

    return S_OK;
}


头
//-----------------------------------------------------------------------------
// File: FileWatch.h
//
// Desc: Class to watch a set of file to see if any change.  If they do
//       then HaveFilesChanged() will return true.
//
// Copyright (C) Microsoft Corporation. All Rights Reserved.
//-----------------------------------------------------------------------------
#pragma once

#define MAX_WATCH_FILES 10

class CFileWatch 
{
public:
    CFileWatch();
    virtual ~CFileWatch();

    HRESULT AddFileToWatch( TCHAR* strWatchFile );
    HRESULT Start();
    BOOL    HaveFilesChanged( BOOL bResetChangeFlag );
    HRESULT Cleanup();
 
public:

protected:
    DWORD   m_dwFileChangeThreadId;
    HANDLE  m_hFileChangeThread;
   
    TCHAR   m_strFilesToWatch[MAX_WATCH_FILES][MAX_PATH];
    int     m_nFilesToWatch;
    BOOL    m_bFileChanged;   

    static DWORD WINAPI StaticFileChangeThreadFunc( LPVOID lpParam );
    DWORD FileChangeThreadFunc();   
};

但是当 游戏运行过程中，创建了一个监视 指定目录和文件的 线程，如果文件内容变化，或者 文件夹名变化， 就会拦截，但是 似乎 Donuts没有进行处理，那么进行什么处理呢，可能 游戏在运行过程中还要利用
改 文件中的路径，或者 重新载入 文件夹里的文件？   目前我只能猜测到这里，但是对于我来说，
这个功能暂时 没有实际意义。