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Detection-CheatEngine/ReadDirectoryChangesPrivate.h

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4.9 KiB

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