hglobalstream.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

/*
 * HGLOBAL Stream implementation
 *
 * This file contains the implementation of the stream interface
 * for streams contained supported by an HGLOBAL pointer.
 *
 * Copyright 1999 Francis Beaudet
 *
 * 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 "config.h"

#include <assert.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#define COBJMACROS
#define NONAMELESSUNION
#define NONAMELESSSTRUCT

#include "windef.h"
#include "winbase.h"
#include "winuser.h"
#include "objbase.h"
#include "ole2.h"
#include "winerror.h"
#include "winternl.h"

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(storage);

/****************************************************************************
 * HGLOBALStreamImpl definition.
 *
 * This class implements the IStream interface and represents a stream
 * supported by an HGLOBAL pointer.
 */
struct HGLOBALStreamImpl
{
  const IStreamVtbl *lpVtbl;   /* Needs to be the first item in the struct
			  * since we want to cast this in an IStream pointer */

  /*
   * Reference count
   */
  LONG		     ref;

  /*
   * Support for the stream
   */
  HGLOBAL supportHandle;

  /*
   * This flag is TRUE if the HGLOBAL is destroyed when the stream
   * is finally released.
   */
  BOOL    deleteOnRelease;

  /*
   * Helper variable that contains the size of the stream
   */
  ULARGE_INTEGER     streamSize;

  /*
   * This is the current position of the cursor in the stream
   */
  ULARGE_INTEGER     currentPosition;
};

typedef struct HGLOBALStreamImpl HGLOBALStreamImpl;

/***
 * This is the destructor of the HGLOBALStreamImpl class.
 *
 * This method will clean-up all the resources used-up by the given HGLOBALStreamImpl
 * class. The pointer passed-in to this function will be freed and will not
 * be valid anymore.
 */
static void HGLOBALStreamImpl_Destroy(HGLOBALStreamImpl* This)
{
  TRACE("(%p)\n", This);

  /*
   * Release the HGlobal if the constructor asked for that.
   */
  if (This->deleteOnRelease)
  {
    GlobalFree(This->supportHandle);
    This->supportHandle=0;
  }

  /*
   * Finally, free the memory used-up by the class.
   */
  HeapFree(GetProcessHeap(), 0, This);
}

/***
 * This implements the IUnknown method AddRef for this
 * class
 */
static ULONG WINAPI HGLOBALStreamImpl_AddRef(
		IStream* iface)
{
  HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
  return InterlockedIncrement(&This->ref);
}

/***
 * This implements the IUnknown method QueryInterface for this
 * class
 */
static HRESULT WINAPI HGLOBALStreamImpl_QueryInterface(
		  IStream*     iface,
		  REFIID         riid,	      /* [in] */
		  void**         ppvObject)   /* [iid_is][out] */
{
  HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;

  /*
   * Perform a sanity check on the parameters.
   */
  if (ppvObject==0)
    return E_INVALIDARG;

  /*
   * Initialize the return parameter.
   */
  *ppvObject = 0;

  /*
   * Compare the riid with the interface IDs implemented by this object.
   */
  if (IsEqualIID(&IID_IUnknown, riid) ||
      IsEqualIID(&IID_ISequentialStream, riid) ||
      IsEqualIID(&IID_IStream, riid))
  {
    *ppvObject = (IStream*)This;
  }

  /*
   * Check that we obtained an interface.
   */
  if ((*ppvObject)==0)
    return E_NOINTERFACE;

  /*
   * Query Interface always increases the reference count by one when it is
   * successful
   */
  HGLOBALStreamImpl_AddRef(iface);

  return S_OK;
}

/***
 * This implements the IUnknown method Release for this
 * class
 */
static ULONG WINAPI HGLOBALStreamImpl_Release(
		IStream* iface)
{
  HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
  ULONG newRef;

  newRef = InterlockedDecrement(&This->ref);

  /*
   * If the reference count goes down to 0, perform suicide.
   */
  if (newRef==0)
  {
    HGLOBALStreamImpl_Destroy(This);
  }

  return newRef;
}

/***
 * This method is part of the ISequentialStream interface.
 *
 * If reads a block of information from the stream at the current
 * position. It then moves the current position at the end of the
 * read block
 *
 * See the documentation of ISequentialStream for more info.
 */
static HRESULT WINAPI HGLOBALStreamImpl_Read(
		  IStream*     iface,
		  void*          pv,        /* [length_is][size_is][out] */
		  ULONG          cb,        /* [in] */
		  ULONG*         pcbRead)   /* [out] */
{
  HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;

  void* supportBuffer;
  ULONG bytesReadBuffer;
  ULONG bytesToReadFromBuffer;

  TRACE("(%p, %p, %d, %p)\n", iface,
	pv, cb, pcbRead);

  /*
   * If the caller is not interested in the nubmer of bytes read,
   * we use another buffer to avoid "if" statements in the code.
   */
  if (pcbRead==0)
    pcbRead = &bytesReadBuffer;

  /*
   * Using the known size of the stream, calculate the number of bytes
   * to read from the block chain
   */
  bytesToReadFromBuffer = min( This->streamSize.u.LowPart - This->currentPosition.u.LowPart, cb);

  /*
   * Lock the buffer in position and copy the data.
   */
  supportBuffer = GlobalLock(This->supportHandle);
  if (!supportBuffer)
  {
      WARN("read from invalid hglobal %p\n", This->supportHandle);
      *pcbRead = 0;
      return S_OK;
  }

  memcpy(pv, (char *) supportBuffer+This->currentPosition.u.LowPart, bytesToReadFromBuffer);

  /*
   * Move the current position to the new position
   */
  This->currentPosition.u.LowPart+=bytesToReadFromBuffer;

  /*
   * Return the number of bytes read.
   */
  *pcbRead = bytesToReadFromBuffer;

  /*
   * Cleanup
   */
  GlobalUnlock(This->supportHandle);

  /*
   * Always returns S_OK even if the end of the stream is reached before the
   * buffer is filled
   */

  return S_OK;
}

/***
 * This method is part of the ISequentialStream interface.
 *
 * It writes a block of information to the stream at the current
 * position. It then moves the current position at the end of the
 * written block. If the stream is too small to fit the block,
 * the stream is grown to fit.
 *
 * See the documentation of ISequentialStream for more info.
 */
static HRESULT WINAPI HGLOBALStreamImpl_Write(
	          IStream*     iface,
		  const void*    pv,          /* [size_is][in] */
		  ULONG          cb,          /* [in] */
		  ULONG*         pcbWritten)  /* [out] */
{
  HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;

  void*          supportBuffer;
  ULARGE_INTEGER newSize;
  ULONG          bytesWritten = 0;

  TRACE("(%p, %p, %d, %p)\n", iface, pv, cb, pcbWritten);

  /*
   * If the caller is not interested in the number of bytes written,
   * we use another buffer to avoid "if" statements in the code.
   */
  if (pcbWritten == 0)
    pcbWritten = &bytesWritten;

  if (cb == 0)
    goto out;

  *pcbWritten = 0;

  newSize.u.HighPart = 0;
  newSize.u.LowPart = This->currentPosition.u.LowPart + cb;

  /*
   * Verify if we need to grow the stream
   */
  if (newSize.u.LowPart > This->streamSize.u.LowPart)
  {
    /* grow stream */
    HRESULT hr = IStream_SetSize(iface, newSize);
    if (FAILED(hr))
    {
      ERR("IStream_SetSize failed with error 0x%08x\n", hr);
      return hr;
    }
  }

  /*
   * Lock the buffer in position and copy the data.
   */
  supportBuffer = GlobalLock(This->supportHandle);
  if (!supportBuffer)
  {
      WARN("write to invalid hglobal %p\n", This->supportHandle);
      return S_OK;
  }

  memcpy((char *) supportBuffer+This->currentPosition.u.LowPart, pv, cb);

  /*
   * Move the current position to the new position
   */
  This->currentPosition.u.LowPart+=cb;

  /*
   * Cleanup
   */
  GlobalUnlock(This->supportHandle);

out:
  /*
   * Return the number of bytes read.
   */
  *pcbWritten = cb;

  return S_OK;
}

/***
 * This method is part of the IStream interface.
 *
 * It will move the current stream pointer according to the parameters
 * given.
 *
 * See the documentation of IStream for more info.
 */
static HRESULT WINAPI HGLOBALStreamImpl_Seek(
		  IStream*      iface,
		  LARGE_INTEGER   dlibMove,         /* [in] */
		  DWORD           dwOrigin,         /* [in] */
		  ULARGE_INTEGER* plibNewPosition) /* [out] */
{
  HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;

  ULARGE_INTEGER newPosition;

  TRACE("(%p, %x%08x, %d, %p)\n", iface, dlibMove.u.HighPart,
	dlibMove.u.LowPart, dwOrigin, plibNewPosition);

  /*
   * The file pointer is moved depending on the given "function"
   * parameter.
   */
  switch (dwOrigin)
  {
    case STREAM_SEEK_SET:
      newPosition.u.HighPart = 0;
      newPosition.u.LowPart = 0;