www.pudn.com > windows2000XP_WDM_DeviceDriverDevelopment_WuAnHe_C > CharFilterInst.h

// CharFilterInst.h : Class declaration CharFilterInstaller. 
// 
 
 
#ifndef __CharFilterInstaller_h__ 
#define __CharFilterInstaller_h__ 
 
 
// Function prototypes 
DWORD AddService(LPCTSTR pszFilterName, LPCTSTR pszServiceBinary); 
DWORD RemoveService(LPCTSTR pszFilterName); 
 
 
////////////////////////////////////////////////////////////////////////////// 
// class CharFilterInstaller 
// 
// This class derives from CDeviceFilterInstaller which does most of the work 
// of installing the filter driver.  Provide the Filter name, Device Class 
// GUID, and flags to the base class.  Implement doLower and/or 
// doUpper to provide a "policy".  Specifically, determine if the given 
// device should be filtered as upper and/or lower filter.  To customize its  
// behavior further, override virtual methods. 
// 
// The class will retrieve a "set" of devices based on the GUID and flags 
// specified.  Then, it will iterate over all the device instances, calling 
// doLower and doUpper for the derived class to choose whether or not to  
// filter the specified device. 
// 
// By default, the base class will attempt to restart the filtered devices 
// in order to have the filter driver loaded.  This behavior can be modified 
// by overriding method RestartDevice().   
// 
// By default, the base class will prepend the filter name to the 
// "UpperFilters"/"LowerFilters" registry property.  This determines the 
// load order of the filter driver.  To alter this behavior, simply override 
// AddFilterName() and implement a custom strategy. 
// 
// This implementation uses "Device Description" as the criteria for  
// comparing devices to install.  Choose an alternate criteria for 
// comparison in the doLower/doUpper methods.  Also, only one device is  
// filterd.  Choose to filter more than one device in the  
// doLower/doUpper methods. 
// 
class CharFilterInstaller : public CDeviceFilterInstaller 
{ 
public: 
	CharFilterInstaller() :  
		CDeviceFilterInstaller(m_szFilterName, m_szFilterSys, m_Guid, m_Flags) 
		{} 
 
	virtual ~CharFilterInstaller(){} 
 
// Helper methods  
	// update Service Control Manager (SCM) database 
	DWORD AddService() { return ::AddService(m_szFilterName,m_szFilterBinary); } 
	DWORD RemoveService() { return ::RemoveService(m_szFilterName); } 
 
protected: 
 
// pure virtual method implementations required by base class 
	// the job is to determine if the device represented by pDevInfo should be filtered 
	// return TRUE to filter the given device, FALSE to not filter it 
	virtual BOOL doLower(CDeviceInfo* pDevInfo) { return FALSE; } 
	virtual BOOL doUpper(CDeviceInfo* pDevInfo); 
	// virtual override to guard against installing the filter more than once 
	virtual DWORD AddUpperFilter(CDeviceInfo* pDevInfo); 
 
// Data members 
public: 
	// Filename for the driver binary - includes partial path 
	static LPCTSTR	m_szFilterBinary; 
 
protected: 
	// Filter Name = must match the service registry key for the filter driver 
	static LPCTSTR	m_szFilterName; 
	// Filename for the driver binary 
	static LPCTSTR	m_szFilterSys; 
	// Device Description of the device to be filtered 
	static LPCTSTR	m_szDeviceDesc; 
	// Class GUID to use in selecting a set of devices that are potentially filtered 
	static GUID		m_Guid; 
	// Flags to help in selecting the set of devices 
	static DWORD	m_Flags; 
}; 
 
 
#endif  //__CharFilterInstaller_h__