Source code of Windows XP (NT5)
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103 lines
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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
LazyReleaseDC.cpp
Abstract:
Delay releasing a DC by one call. A DC is not released until the next call to ReleaseDC
Notes:
This is a general purpose shim.
History:
10/10/1999 linstev Created
--*/
#include "precomp.h"
IMPLEMENT_SHIM_BEGIN(LazyReleaseDC)
#include "ShimHookMacro.h"
APIHOOK_ENUM_BEGIN
APIHOOK_ENUM_ENTRY(ReleaseDC)
APIHOOK_ENUM_END
HWND g_hWndPrev;
HDC g_hDcPrev;
CRITICAL_SECTION g_MakeThreadSafe;
/*++
Save this hWnd and hdc for releasing later. If there is already a DC to be
released, release it now.
--*/
int
APIHOOK(ReleaseDC)(
HWND hWnd,
HDC hdc
)
{
UINT uRet = 1; // All's well
EnterCriticalSection(&g_MakeThreadSafe);
// If there is a previous DC, release it now
if (g_hDcPrev) {
uRet = ORIGINAL_API(ReleaseDC)(g_hWndPrev, g_hDcPrev);
}
g_hWndPrev = hWnd;
g_hDcPrev = hdc;
LeaveCriticalSection(&g_MakeThreadSafe);
return uRet;
}
/*++
Register hooked functions
--*/
BOOL
NOTIFY_FUNCTION(
DWORD fdwReason
)
{
if (fdwReason == DLL_PROCESS_ATTACH) {
g_hWndPrev = 0;
g_hDcPrev = 0;
InitializeCriticalSection(&g_MakeThreadSafe);
}
// Ignore Detach code
/*
else if (fdwReason == DLL_PROCESS_DETACH) {
DeleteCriticalSection(&g_MakeThreadSafe);
}
*/
return TRUE;
}
HOOK_BEGIN
CALL_NOTIFY_FUNCTION
APIHOOK_ENTRY(USER32.DLL, ReleaseDC)
HOOK_END
IMPLEMENT_SHIM_END