windows-xp/Source/XPSP1/NT/shell/tools/starbuck/dllload.cpp

/*****************************************************************************\
    FILE: dllload.cpp

    DESCRIPTION:
       This file will create stub functions that will just-in-time load a DLL
    and call an API.  This will delay loading functions that either take a long
    time to load or may not exist in certain install cases.

    BryanSt 4/4/2000 (Bryan Starbuck)
    Copyright (C) Microsoft Corp 2000-2000. All rights reserved.
\*****************************************************************************/

#include "priv.h"
#include <wininet.h>
#include <guiddef.h>

#pragma warning(disable:4229)  // No warnings when modifiers used on data

// Delay loading mechanism.  This allows you to write code as if you are
// calling implicitly linked APIs, and yet have these APIs really be
// explicitly linked.  You can reduce the initial number of DLLs that 
// are loaded (load on demand) using this technique.
//
// Use the following macros to indicate which APIs/DLLs are delay-linked
// and -loaded.
//
//      DELAY_LOAD
//      DELAY_LOAD_HRESULT
//      DELAY_LOAD_SAFEARRAY
//      DELAY_LOAD_UINT
//      DELAY_LOAD_INT
//      DELAY_LOAD_VOID
//
// Use these macros for APIs that are exported by ordinal only.
//
//      DELAY_LOAD_ORD
//      DELAY_LOAD_ORD_VOID     
//
// Use these macros for APIs that only exist on the integrated-shell
// installations (i.e., a new shell32 is on the system).
//
//      DELAY_LOAD_SHELL
//      DELAY_LOAD_SHELL_HRESULT
//      DELAY_LOAD_SHELL_VOID     
//
// 


/**********************************************************************/

void _GetProcFromDLL(HINSTANCE* phinst, LPCSTR pszDLL, FARPROC* ppfn, LPCSTR pszProc)
{
#ifdef DEBUG
    CHAR szProcD[MAX_PATH];
    if (HIWORD(pszProc)) {
        lstrcpynA(szProcD, pszProc, ARRAYSIZE(szProcD));
    } else {
        wnsprintfA(szProcD, ARRAYSIZE(szProcD), "(ordinal %d)", LOWORD(pszProc));
    }
#endif // DEBUG
    // If it's already loaded, return.
    if (*ppfn) {
    return;
    }

    if (*phinst == NULL) {
#ifdef DEBUG
    TraceMsg(TF_WMTHEME, "DLLLOAD: Loading %s for the first time for %s", pszDLL, szProcD);
    
    if (g_dwBreakFlags & 0x00000080)
    {
        DebugBreak();
    }
#endif // DEBUG
    *phinst = LoadLibraryA(pszDLL);
    if (*phinst == NULL) {
        return;
    }
    }

#ifdef DEBUG
    TraceMsg(TF_WMTHEME, "DLLLOAD: GetProc'ing %s from %s for the first time", pszDLL, szProcD);
#endif // DEBUG
    *ppfn = GetProcAddress(*phinst, pszProc);
}

/*----------------------------------------------------------
Purpose: Performs a loadlibrary on the DLL only if the machine
     has the integrated shell installation.

*/
void _SHGetProcFromDLL(HINSTANCE* phinst, LPCSTR pszDLL, FARPROC* ppfn, LPCSTR pszProc)
{
    _GetProcFromDLL(phinst, pszDLL, ppfn, pszProc);
}

#define DELAY_LOAD_MAP(_hinst, _dll, _ret, _fnpriv, _fn, _args, _nargs, _err) \
_ret __stdcall _fnpriv _args                \
{                                       \
    static _ret (* __stdcall _pfn##_fn) _args = NULL;   \
    _GetProcFromDLL(&_hinst, #_dll, (FARPROC*)&_pfn##_fn, #_fn); \
    if (_pfn##_fn)               \
    return _pfn##_fn _nargs; \
    return (_ret)_err;           \
}

#define DELAY_MAP_HRESULT(_hinst, _dll, _fnpriv, _fn, _args, _nargs) DELAY_LOAD_MAP(_hinst, _dll, HRESULT, _fnpriv, _fn, _args, _nargs, E_FAIL)
#define DELAY_MAP_DWORD(_hinst, _dll, _fnpriv, _fn, _args, _nargs) DELAY_LOAD_MAP(_hinst, _dll, DWORD, _fnpriv, _fn, _args, _nargs, 0)


#define DELAY_LOAD_ERR(_hinst, _dll, _ret, _fn, _args, _nargs, _err)    DELAY_LOAD_MAP(_hinst, _dll, _ret, _fn, _fn, _args, _nargs, _err)

#define DELAY_LOAD(_hinst, _dll, _ret, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, _ret, _fn, _args, _nargs, 0)
#define DELAY_LOAD_HRESULT(_hinst, _dll, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, HRESULT, _fn, _args, _nargs, E_FAIL)
#define DELAY_LOAD_SAFEARRAY(_hinst, _dll, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, SAFEARRAY *, _fn, _args, _nargs, NULL)
#define DELAY_LOAD_DWORD(_hinst, _dll, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, DWORD, _fn, _args, _nargs, 0)
#define DELAY_LOAD_UINT(_hinst, _dll, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, UINT, _fn, _args, _nargs, 0)
#define DELAY_LOAD_INT(_hinst, _dll, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, INT, _fn, _args, _nargs, 0)
#define DELAY_LOAD_BOOL(_hinst, _dll, _fn, _args, _nargs) DELAY_LOAD_ERR(_hinst, _dll, BOOL, _fn, _args, _nargs, FALSE)

#define DELAY_LOAD_VOID(_hinst, _dll, _fn, _args, _nargs) \
void __stdcall _fn _args                \
{                                       \
    static void (* __stdcall _pfn##_fn) _args = NULL;   \
    _GetProcFromDLL(&_hinst, #_dll, (FARPROC*)&_pfn##_fn, #_fn); \
    if (_pfn##_fn)              \
    _pfn##_fn _nargs;       \
    return;                     \
}

//
// For private entrypoints exported by ordinal.
// 

#define DELAY_LOAD_ORD_ERR(_hinst, _dll, _ret, _fn, _ord, _args, _nargs, _err) \
_ret __stdcall _fn _args                \
{                                       \
    static _ret (* __stdcall _pfn##_fn) _args = NULL;   \
    _GetProcFromDLL(&_hinst, #_dll, (FARPROC*)&_pfn##_fn, (LPCSTR)_ord);   \
    if (_pfn##_fn)               \
    return _pfn##_fn _nargs; \
    return (_ret)_err;           \
}
    
#define DELAY_LOAD_ORD(_hinst, _dll, _ret, _fn, _ord, _args, _nargs) DELAY_LOAD_ORD_ERR(_hinst, _dll, _ret, _fn, _ord, _args, _nargs, 0)
#define DELAY_LOAD_ORD_HRESULT(_hinst, _dll, _fn, _ord, _args, _nargs) DELAY_LOAD_ORD(_hinst, _dll, HRESULT, _fn, _ord, _args, _nargs)


#define DELAY_LOAD_ORD_VOID(_hinst, _dll, _fn, _ord, _args, _nargs) \
void __stdcall _fn _args                \
{                                       \
    static void (* __stdcall _pfn##_fn) _args = NULL;   \
    _GetProcFromDLL(&_hinst, #_dll, (FARPROC*)&_pfn##_fn, (LPCSTR)_ord);   \
    if (_pfn##_fn)              \
    _pfn##_fn _nargs;       \
    return;                     \
}


//
//  Private exports by ordinal for integrated-shell installs
//


#define DELAY_LOAD_SHELL_ERR(_hinst, _dll, _ret, _fn, _ord, _args, _nargs, _err) \
_ret __stdcall _fn _args                \
{                                       \
    static _ret (* __stdcall _pfn##_fn) _args = NULL;   \
    _SHGetProcFromDLL(&_hinst, #_dll, (FARPROC*)&_pfn##_fn, (LPCSTR)_ord);   \
    if (_pfn##_fn)               \
    return _pfn##_fn _nargs; \
    return (_ret)_err;           \
}
    
#define DELAY_LOAD_SHELL(_hinst, _dll, _ret, _fn, _ord, _args, _nargs) DELAY_LOAD_SHELL_ERR(_hinst, _dll, _ret, _fn, _ord, _args, _nargs, 0)
#define DELAY_LOAD_SHELL_HRESULT(_hinst, _dll, _fn, _ord, _args, _nargs) DELAY_LOAD_SHELL_ERR(_hinst, _dll, HRESULT, _fn, _ord, _args, _nargs, E_FAIL)


#define DELAY_LOAD_SHELL_VOID(_hinst, _dll, _fn, _ord, _args, _nargs) \
void __stdcall _fn _args                \
{                                       \
    static void (* __stdcall _pfn##_fn) _args = NULL;   \
    _SHGetProcFromDLL(&_hinst, #_dll, (FARPROC*)&_pfn##_fn, (LPCSTR)_ord); \
    if (_pfn##_fn)              \
    _pfn##_fn _nargs;       \
    return;                     \
}



/**********************************************************************/
// --------- WINMM.DLL ---------------
HINSTANCE g_hinstWINMM = NULL;

DELAY_LOAD_BOOL(g_hinstWINMM, WINMM.DLL, sndPlaySoundW,
                 (LPCWSTR pszSound, UINT fuSound), 
                 (pszSound, fuSound));


/**********************************************************************/
#pragma warning(default:4229)