oleaut.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

/*
 *	OLEAUT32
 *
 * Copyright 1999, 2000 Marcus Meissner
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <stdarg.h>
#include <string.h>
#include <limits.h>

#define COBJMACROS

#include "windef.h"
#include "winbase.h"
#include "wingdi.h"
#include "winuser.h"
#include "winerror.h"

#include "ole2.h"
#include "olectl.h"
#include "oleauto.h"
#include "typelib.h"

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(ole);

static BOOL BSTR_bCache = TRUE; /* Cache allocations to minimise alloc calls? */

HMODULE OLEAUT32_hModule = NULL;

/******************************************************************************
 * BSTR  {OLEAUT32}
 *
 * NOTES
 *  BSTR is a simple typedef for a wide-character string used as the principle
 *  string type in ole automation. When encapsulated in a Variant type they are
 *  automatically copied and destroyed as the variant is processed.
 *
 *  The low level BSTR Api allows manipulation of these strings and is used by
 *  higher level Api calls to manage the strings transparently to the caller.
 *
 *  Internally the BSTR type is allocated with space for a DWORD byte count before
 *  the string data begins. This is undocumented and non-system code should not
 *  access the count directly. Use SysStringLen() or SysStringByteLen()
 *  instead. Note that the byte count does not include the terminating NUL.
 *
 *  To create a new BSTR, use SysAllocString(), SysAllocStringLen() or
 *  SysAllocStringByteLen(). To change the size of an existing BSTR, use SysReAllocString()
 *  or SysReAllocStringLen(). Finally to destroy a string use SysFreeString().
 *
 *  BSTR's are cached by Ole Automation by default. To override this behaviour
 *  either set the environment variable 'OANOCACHE', or call SetOaNoCache().
 *
 * SEE ALSO
 *  'Inside OLE, second edition' by Kraig Brockshmidt.
 */

/******************************************************************************
 *             SysStringLen  [OLEAUT32.7]
 *
 * Get the allocated length of a BSTR in wide characters.
 *
 * PARAMS
 *  str [I] BSTR to find the length of
 *
 * RETURNS
 *  The allocated length of str, or 0 if str is NULL.
 *
 * NOTES
 *  See BSTR.
 *  The returned length may be different from the length of the string as
 *  calculated by lstrlenW(), since it returns the length that was used to
 *  allocate the string by SysAllocStringLen().
 */
UINT WINAPI SysStringLen(BSTR str)
{
    DWORD* bufferPointer;

     if (!str) return 0;
    /*
     * The length of the string (in bytes) is contained in a DWORD placed
     * just before the BSTR pointer
     */
    bufferPointer = (DWORD*)str;

    bufferPointer--;

    return (int)(*bufferPointer/sizeof(WCHAR));
}

/******************************************************************************
 *             SysStringByteLen  [OLEAUT32.149]
 *
 * Get the allocated length of a BSTR in bytes.
 *
 * PARAMS
 *  str [I] BSTR to find the length of
 *
 * RETURNS
 *  The allocated length of str, or 0 if str is NULL.
 *
 * NOTES
 *  See SysStringLen(), BSTR().
 */
UINT WINAPI SysStringByteLen(BSTR str)
{
    DWORD* bufferPointer;

     if (!str) return 0;
    /*
     * The length of the string (in bytes) is contained in a DWORD placed
     * just before the BSTR pointer
     */
    bufferPointer = (DWORD*)str;

    bufferPointer--;

    return (int)(*bufferPointer);
}

/******************************************************************************
 *		SysAllocString	[OLEAUT32.2]
 *
 * Create a BSTR from an OLESTR.
 *
 * PARAMS
 *  str [I] Source to create BSTR from
 *
 * RETURNS
 *  Success: A BSTR allocated with SysAllocStringLen().
 *  Failure: NULL, if oleStr is NULL.
 *
 * NOTES
 *  See BSTR.
 *  MSDN (October 2001) incorrectly states that NULL is returned if oleStr has
 *  a length of 0. Native Win32 and this implementation both return a valid
 *  empty BSTR in this case.
 */
BSTR WINAPI SysAllocString(LPCOLESTR str)
{
    if (!str) return 0;

    /* Delegate this to the SysAllocStringLen32 method. */
    return SysAllocStringLen(str, lstrlenW(str));
}

/******************************************************************************
 *		SysFreeString	[OLEAUT32.6]
 *
 * Free a BSTR.
 *
 * PARAMS
 *  str [I] BSTR to free.
 *
 * RETURNS
 *  Nothing.
 *
 * NOTES
 *  See BSTR.
 *  str may be NULL, in which case this function does nothing.
 */
void WINAPI SysFreeString(BSTR str)
{
    DWORD* bufferPointer;

    /* NULL is a valid parameter */
    if(!str) return;

    /*
     * We have to be careful when we free a BSTR pointer, it points to
     * the beginning of the string but it skips the byte count contained
     * before the string.
     */
    bufferPointer = (DWORD*)str;

    bufferPointer--;

    /*
     * Free the memory from its "real" origin.
     */
    HeapFree(GetProcessHeap(), 0, bufferPointer);
}

/******************************************************************************
 *             SysAllocStringLen     [OLEAUT32.4]
 *
 * Create a BSTR from an OLESTR of a given wide character length.
 *
 * PARAMS
 *  str [I] Source to create BSTR from
 *  len [I] Length of oleStr in wide characters
 *
 * RETURNS
 *  Success: A newly allocated BSTR from SysAllocStringByteLen()
 *  Failure: NULL, if len is >= 0x80000000, or memory allocation fails.
 *
 * NOTES
 *  See BSTR(), SysAllocStringByteLen().
 */
BSTR WINAPI SysAllocStringLen(const OLECHAR *str, unsigned int len)
{
    DWORD  bufferSize;
    DWORD* newBuffer;
    WCHAR* stringBuffer;

    /* Detect integer overflow. */
    if (len >= ((UINT_MAX-sizeof(WCHAR)-sizeof(DWORD))/sizeof(WCHAR)))
	return NULL;
    /*
     * Find the length of the buffer passed-in, in bytes.
     */
    bufferSize = len * sizeof (WCHAR);

    /*
     * Allocate a new buffer to hold the string.
     * don't forget to keep an empty spot at the beginning of the
     * buffer for the character count and an extra character at the
     * end for the NULL.
     */
    newBuffer = HeapAlloc(GetProcessHeap(), 0,
                          bufferSize + sizeof(WCHAR) + sizeof(DWORD));

    /*
     * If the memory allocation failed, return a null pointer.
     */
    if (!newBuffer)
      return NULL;

    /*
     * Copy the length of the string in the placeholder.
     */
    *newBuffer = bufferSize;

    /*
     * Skip the byte count.
     */
    newBuffer++;

    /*
     * Copy the information in the buffer.
     * Since it is valid to pass a NULL pointer here, we'll initialize the
     * buffer to nul if it is the case.
     */
    if (str != 0)
      memcpy(newBuffer, str, bufferSize);
    else
      memset(newBuffer, 0, bufferSize);

    /*
     * Make sure that there is a nul character at the end of the
     * string.
     */
    stringBuffer = (WCHAR*)newBuffer;
    stringBuffer[len] = '\0';

    return (LPWSTR)stringBuffer;
}

/******************************************************************************
 *             SysReAllocStringLen   [OLEAUT32.5]
 *
 * Change the length of a previously created BSTR.
 *
 * PARAMS
 *  old [O] BSTR to change the length of
 *  str [I] New source for pbstr
 *  len [I] Length of oleStr in wide characters
 *
 * RETURNS
 *  Success: 1. The size of pbstr is updated.
 *  Failure: 0, if len >= 0x80000000 or memory allocation fails.
 *
 * NOTES
 *  See BSTR(), SysAllocStringByteLen().
 *  *pbstr may be changed by this function.
 */
int WINAPI SysReAllocStringLen(BSTR* old, const OLECHAR* str, unsigned int len)
{
    if (*old!=NULL) {
      DWORD newbytelen = len*sizeof(WCHAR);
      DWORD *ptr = HeapReAlloc(GetProcessHeap(),0,((DWORD*)*old)-1,newbytelen+sizeof(WCHAR)+sizeof(DWORD));
      *old = (BSTR)(ptr+1);
      *ptr = newbytelen;
      if (str) {
        memcpy(*old, str, newbytelen);
        (*old)[len] = 0;
      } else {
	/* Subtle hidden feature: The old string data is still there
	 * when 'in' is NULL!
	 * Some Microsoft program needs it.
	 */
      }
    } else {
      /*
       * Allocate the new string
       */
      *old = SysAllocStringLen(str, len);
    }

    return 1;
}

/******************************************************************************
 *             SysAllocStringByteLen     [OLEAUT32.150]
 *
 * Create a BSTR from an OLESTR of a given byte length.
 *
 * PARAMS
 *  str [I] Source to create BSTR from
 *  len [I] Length of oleStr in bytes
 *
 * RETURNS
 *  Success: A newly allocated BSTR
 *  Failure: NULL, if len is >= 0x80000000, or memory allocation fails.
 *
 * NOTES
 *  -If len is 0 or oleStr is NULL the resulting string is empty ("").
 *  -This function always NUL terminates the resulting BSTR.
 *  -oleStr may be either an LPCSTR or LPCOLESTR, since it is copied
 *  without checking for a terminating NUL.
 *  See BSTR.
 */
BSTR WINAPI SysAllocStringByteLen(LPCSTR str, UINT len)
{
    DWORD* newBuffer;
    char* stringBuffer;

    /*
     * Allocate a new buffer to hold the string.
     * don't forget to keep an empty spot at the beginning of the
     * buffer for the character count and an extra character at the
     * end for the NULL.
     */
    newBuffer = HeapAlloc(GetProcessHeap(), 0,
                          len + sizeof(WCHAR) + sizeof(DWORD));

    /*
     * If the memory allocation failed, return a null pointer.
     */
    if (newBuffer==0)
      return 0;

    /*
     * Copy the length of the string in the placeholder.
     */
    *newBuffer = len;

    /*
     * Skip the byte count.
     */
    newBuffer++;

    /*
     * Copy the information in the buffer.
     * Since it is valid to pass a NULL pointer here, we'll initialize the
     * buffer to nul if it is the case.
     */
    if (str != 0)
      memcpy(newBuffer, str, len);

    /*
     * Make sure that there is a nul character at the end of the
     * string.
     */
    stringBuffer = (char *)newBuffer;
    stringBuffer[len] = 0;
    stringBuffer[len+1] = 0;

    return (LPWSTR)stringBuffer;
}

/******************************************************************************
 *		SysReAllocString	[OLEAUT32.3]
 *
 * Change the length of a previously created BSTR.
 *
 * PARAMS
 *  old [I/O] BSTR to change the length of
 *  str [I]   New source for pbstr
 *
 * RETURNS
 *  Success: 1
 *  Failure: 0.
 *
 * NOTES
 *  See BSTR(), SysAllocStringStringLen().
 */
INT WINAPI SysReAllocString(LPBSTR old,LPCOLESTR str)
{
    /*
     * Sanity check
     */
    if (old==NULL)
      return 0;

    /*
     * Make sure we free the old string.
     */
    if (*old!=NULL)
      SysFreeString(*old);

    /*
     * Allocate the new string
     */
    *old = SysAllocString(str);

     return 1;
}

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