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178 lines
4.9 KiB
178 lines
4.9 KiB
//
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// The MIT License
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//
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// Copyright (c) 2010 James E Beveridge
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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// This sample code is for my blog entry titled, "Understanding ReadDirectoryChangesW"
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// http://qualapps.blogspot.com/2010/05/understanding-readdirectorychangesw.html
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// See ReadMe.txt for overview information.
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class CReadDirectoryChanges;
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namespace ReadDirectoryChangesPrivate
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{
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class CReadChangesServer;
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///////////////////////////////////////////////////////////////////////////
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// All functions in CReadChangesRequest run in the context of the worker thread.
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// One instance of this object is created for each call to AddDirectory().
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class CReadChangesRequest
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{
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public:
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CReadChangesRequest(CReadChangesServer* pServer, LPCTSTR sz, BOOL b, DWORD dw, DWORD size);
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~CReadChangesRequest();
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bool OpenDirectory();
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void BeginRead();
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// The dwSize is the actual number of bytes sent to the APC.
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void BackupBuffer(DWORD dwSize)
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{
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// We could just swap back and forth between the two
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// buffers, but this code is easier to understand and debug.
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memcpy(&m_BackupBuffer[0], &m_Buffer[0], dwSize);
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}
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void ProcessNotification();
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void RequestTermination()
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{
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::CancelIo(m_hDirectory);
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::CloseHandle(m_hDirectory);
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m_hDirectory = nullptr;
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}
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CReadChangesServer* m_pServer;
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protected:
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static VOID CALLBACK NotificationCompletion(
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DWORD dwErrorCode, // completion code
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DWORD dwNumberOfBytesTransfered, // number of bytes transferred
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LPOVERLAPPED lpOverlapped); // I/O information buffer
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// Parameters from the caller for ReadDirectoryChangesW().
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DWORD m_dwFilterFlags;
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BOOL m_bIncludeChildren;
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std::wstring m_wstrDirectory;
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// Result of calling CreateFile().
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HANDLE m_hDirectory;
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// Required parameter for ReadDirectoryChangesW().
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OVERLAPPED m_Overlapped;
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// Data buffer for the request.
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// Since the memory is allocated by malloc, it will always
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// be aligned as required by ReadDirectoryChangesW().
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vector<BYTE> m_Buffer;
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// Double buffer strategy so that we can issue a new read
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// request before we process the current buffer.
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vector<BYTE> m_BackupBuffer;
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};
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///////////////////////////////////////////////////////////////////////////
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// All functions in CReadChangesServer run in the context of the worker thread.
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// One instance of this object is allocated for each instance of CReadDirectoryChanges.
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// This class is responsible for thread startup, orderly thread shutdown, and shimming
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// the various C++ member functions with C-style Win32 functions.
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class CReadChangesServer
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{
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public:
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CReadChangesServer(CReadDirectoryChanges* pParent)
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{
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m_bTerminate=false; m_nOutstandingRequests=0;m_pBase=pParent;
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}
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static unsigned int WINAPI ThreadStartProc(LPVOID arg)
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{
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CReadChangesServer* pServer = (CReadChangesServer*)arg;
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pServer->Run();
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return 0;
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}
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// Called by QueueUserAPC to start orderly shutdown.
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static void CALLBACK TerminateProc(__in ULONG_PTR arg)
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{
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CReadChangesServer* pServer = (CReadChangesServer*)arg;
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pServer->RequestTermination();
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}
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// Called by QueueUserAPC to add another directory.
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static void CALLBACK AddDirectoryProc(__in ULONG_PTR arg)
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{
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CReadChangesRequest* pRequest = (CReadChangesRequest*)arg;
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pRequest->m_pServer->AddDirectory(pRequest);
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}
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CReadDirectoryChanges* m_pBase;
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volatile DWORD m_nOutstandingRequests;
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protected:
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void Run()
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{
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while (m_nOutstandingRequests || !m_bTerminate)
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{
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DWORD rc = ::SleepEx(INFINITE, true);
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}
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}
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void AddDirectory( CReadChangesRequest* pBlock )
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{
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if (pBlock->OpenDirectory())
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{
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::InterlockedIncrement(&pBlock->m_pServer->m_nOutstandingRequests);
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m_pBlocks.push_back(pBlock);
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pBlock->BeginRead();
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}
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else
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delete pBlock;
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}
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void RequestTermination()
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{
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m_bTerminate = true;
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for (DWORD i=0; i<m_pBlocks.size(); ++i)
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{
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// Each Request object will delete itself.
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m_pBlocks[i]->RequestTermination();
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}
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m_pBlocks.clear();
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}
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vector<CReadChangesRequest*> m_pBlocks;
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bool m_bTerminate;
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};
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}
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