Mouse Gestures for Internet Explorer

///////////////////////////////////////////////////////////////
//
// WindowHook.cpp
//
// Created: 29/07/2003
// Copyright (c) 2003 Ralph Hare (ralph.hare@ysgyfarnog.co.uk)
// All rights reserved.
//
// The code and information is provided "as-is" without
// warranty of any kind, either expressed or implied.
//
///////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "WindowHook.h"
#include "WindowHelper.h"

WindowHook::WindowHook() :
    m_hook( NULL ),
    m_pObserver( NULL )
{
    m_hook = ::SetWindowsHookEx( 
                        WH_CALLWNDPROCRET,
                        CallWndRetProc,
                        _Module.GetModuleInstance(),
                        ::GetCurrentThreadId()
                        );

    if( m_hook == NULL )
    {
        ATLASSERT( FALSE );
    }
}

WindowHook::~WindowHook()
{
    if( m_hook )
    {
        ::UnhookWindowsHookEx( m_hook );
    }
}

LRESULT WindowHook::CallWndRetProc( int nCode, WPARAM wParam, LPARAM lParam )
{
    return WindowHookManager::GetInstance().GetHook()->OnHook( nCode, wParam, lParam );
}

LRESULT WindowHook::OnHook( int nCode, WPARAM wParam, LPARAM lParam )
{
    if( nCode == HC_ACTION )
    {
        if( lParam && m_pObserver )
        {
            CWPRETSTRUCT    *pCWPR = reinterpret_cast< CWPRETSTRUCT * >( lParam );

            switch( pCWPR->message )                
            {
            case WM_CREATE:
            case WM_DESTROY:
                if( pCWPR->message == WM_CREATE )
                {
                    if( pCWPR->lResult != -1 )
                    {
                        m_pObserver->OnCreate( pCWPR->hwnd );
                    }
                }
                else
                {
                    if( pCWPR->lResult == 0 )
                    {
                        m_pObserver->OnDestroy( pCWPR->hwnd );
                    }
                }
                break;
            }
        }
    }

    return ::CallNextHookEx( m_hook, nCode, wParam, lParam );
}

///////////////////////////////////////////////////////////////////////////////

WindowHookManager::WindowHookManager() :
    m_tlsIndex( ::TlsAlloc() )
{        
    ATLASSERT( m_tlsIndex != 0 );
}

WindowHookManager::~WindowHookManager()
{
    if( m_tlsIndex )
    {
        ::TlsFree( m_tlsIndex );
    }
}

WindowHook * WindowHookManager::GetHook()
{
    if( m_tlsIndex == 0 )
    {
        return NULL;
    }

    WindowHook *pHook = reinterpret_cast< WindowHook * >( ::TlsGetValue( m_tlsIndex ) );

    if( pHook == NULL )
    {
        pHook = new WindowHook();
        ::TlsSetValue( m_tlsIndex, pHook );
    }
#ifdef _DEBUG
    else
    {
        ATLASSERT( ::IsBadReadPtr( pHook, sizeof( WindowHook ) ) == FALSE );
        ATLASSERT( ::IsBadWritePtr( pHook, sizeof( WindowHook ) ) == FALSE );
    }
#endif

    return pHook;
}

void WindowHookManager::AttachHook( WindowHook::Observer *pObserver )
{
    WindowHook  *pHook = GetHook();

    if( pHook )
    {
        pHook->m_pObserver = pObserver;
    }
}

void WindowHookManager::ReleaseHook()
{
    if( m_tlsIndex == 0 )
    {
        return;
    }

    WindowHook *pHook = reinterpret_cast< WindowHook * >( ::TlsGetValue( m_tlsIndex ) );

    if( pHook )
    {
    #ifdef _DEBUG
        ATLASSERT( ::IsBadReadPtr( pHook, sizeof( WindowHook ) ) == FALSE );
        ATLASSERT( ::IsBadWritePtr( pHook, sizeof( WindowHook ) ) == FALSE );
    #endif

        delete  pHook;
        ::TlsSetValue( m_tlsIndex, NULL );
    }
}

WindowHookManager & WindowHookManager::GetInstance()
{
    static WindowHookManager    instance;
    return instance;
}