stg_stream.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

/*
 * Compound Storage (32 bit version)
 * Stream implementation
 *
 * This file contains the implementation of the stream interface
 * for streams contained in a compound storage.
 *
 * Copyright 1999 Francis Beaudet
 * Copyright 1999 Thuy Nguyen
 *
 * 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 <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 "winerror.h"
#include "winternl.h"
#include "wine/debug.h"

#include "storage32.h"

WINE_DEFAULT_DEBUG_CHANNEL(storage);


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

  /*
   * Release the reference we are holding on the parent storage.
   * IStorage_Release((IStorage*)This->parentStorage);
   *
   * No, don't do this. Some apps call IStorage_Release without
   * calling IStream_Release first. If we grab a reference the
   * file is not closed, and the app fails when it tries to
   * reopen the file (Easy-PC, for example). Just inform the
   * storage that we have closed the stream
   */

  if(This->parentStorage) {

    StorageBaseImpl_RemoveStream(This->parentStorage, This);

  }

  This->parentStorage = 0;

  /*
   * Make sure we clean-up the block chain stream objects that we were using.
   */
  if (This->bigBlockChain != 0)
  {
    BlockChainStream_Destroy(This->bigBlockChain);
    This->bigBlockChain = 0;
  }

  if (This->smallBlockChain != 0)
  {
    SmallBlockChainStream_Destroy(This->smallBlockChain);
    This->smallBlockChain = 0;
  }

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

/***
 * This implements the IUnknown method QueryInterface for this
 * class
 */
static HRESULT WINAPI StgStreamImpl_QueryInterface(
		  IStream*     iface,
		  REFIID         riid,	      /* [in] */
		  void**         ppvObject)   /* [iid_is][out] */
{
  StgStreamImpl* const This=(StgStreamImpl*)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_IPersist, riid) ||
      IsEqualIID(&IID_IPersistStream, 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
   */
  IStream_AddRef(iface);

  return S_OK;
}

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

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

  ULONG ref;

  ref = InterlockedDecrement(&This->ref);

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

  return ref;
}

/***
 * This method will open the block chain pointed by the property
 * that describes the stream.
 * If the stream's size is null, no chain is opened.
 */
static void StgStreamImpl_OpenBlockChain(
        StgStreamImpl* This)
{
  StgProperty    curProperty;
  BOOL         readSuccessful;

  /*
   * Make sure no old object is left over.
   */
  if (This->smallBlockChain != 0)
  {
    SmallBlockChainStream_Destroy(This->smallBlockChain);
    This->smallBlockChain = 0;
  }

  if (This->bigBlockChain != 0)
  {
    BlockChainStream_Destroy(This->bigBlockChain);
    This->bigBlockChain = 0;
  }

  /*
   * Read the information from the property.
   */
  readSuccessful = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
					     This->ownerProperty,
					     &curProperty);

  if (readSuccessful)
  {
    This->streamSize = curProperty.size;

    /*
     * This code supports only streams that are <32 bits in size.
     */
    assert(This->streamSize.u.HighPart == 0);

    if(curProperty.startingBlock == BLOCK_END_OF_CHAIN)
    {
      assert( (This->streamSize.u.HighPart == 0) && (This->streamSize.u.LowPart == 0) );
    }
    else
    {
      if ( (This->streamSize.u.HighPart == 0) &&
	   (This->streamSize.u.LowPart < LIMIT_TO_USE_SMALL_BLOCK) )
      {
	This->smallBlockChain = SmallBlockChainStream_Construct(
								This->parentStorage->ancestorStorage,
								This->ownerProperty);
      }
      else
      {
	This->bigBlockChain = BlockChainStream_Construct(
							 This->parentStorage->ancestorStorage,
							 NULL,
							 This->ownerProperty);
      }
    }
  }
}

/***
 * This method is part of the ISequentialStream interface.
 *
 * It 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 StgStreamImpl_Read(
		  IStream*     iface,
		  void*          pv,        /* [length_is][size_is][out] */
		  ULONG          cb,        /* [in] */
		  ULONG*         pcbRead)   /* [out] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

  ULONG bytesReadBuffer;
  ULONG bytesToReadFromBuffer;
  HRESULT res;

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

  if (!This->parentStorage)
  {
    WARN("storage reverted\n");
    return STG_E_REVERTED;
  }

  /*
   * If the caller is not interested in the number 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);

  /*
   * Depending on the type of chain that was opened when the stream was constructed,
   * we delegate the work to the method that reads the block chains.
   */
  if (This->smallBlockChain!=0)
  {
    res = SmallBlockChainStream_ReadAt(This->smallBlockChain,
				 This->currentPosition,
				 bytesToReadFromBuffer,
				 pv,
				 pcbRead);

  }
  else if (This->bigBlockChain!=0)
  {
    res = BlockChainStream_ReadAt(This->bigBlockChain,
                 This->currentPosition,
                 bytesToReadFromBuffer,
                 pv,
                 pcbRead);
  }
  else
  {
    /*
     * Small and big block chains are both NULL. This case will happen
     * when a stream starts with BLOCK_END_OF_CHAIN and has size zero.
     */

    *pcbRead = 0;
    res = S_OK;
    goto end;
  }

  if (SUCCEEDED(res))
  {
      /*
       * We should always be able to read the proper amount of data from the
       * chain.
       */
      assert(bytesToReadFromBuffer == *pcbRead);

      /*
       * Advance the pointer for the number of positions read.
       */
      This->currentPosition.u.LowPart += *pcbRead;
  }

end:
  TRACE("<-- %08x\n", res);
  return res;
}

/***
 * 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 StgStreamImpl_Write(
	          IStream*     iface,
		  const void*    pv,          /* [size_is][in] */
		  ULONG          cb,          /* [in] */
		  ULONG*         pcbWritten)  /* [out] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

  ULARGE_INTEGER newSize;
  ULONG bytesWritten = 0;
  HRESULT res;

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

  /*
   * Do we have permission to write to this stream?
   */
  switch(STGM_ACCESS_MODE(This->grfMode))
  {
  case STGM_WRITE:
  case STGM_READWRITE:
      break;
  default:
      WARN("access denied by flags: 0x%x\n", STGM_ACCESS_MODE(This->grfMode));
      return STG_E_ACCESSDENIED;
  }

  if (!pv)
    return STG_E_INVALIDPOINTER;

  if (!This->parentStorage)
  {
    WARN("storage reverted\n");
    return STG_E_REVERTED;
  }
 
  /*
   * 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;

  /*
   * Initialize the out parameter
   */
  *pcbWritten = 0;

  if (cb == 0)
  {
    TRACE("<-- S_OK, written 0\n");
    return S_OK;
  }
  else
  {
    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 */
    res = IStream_SetSize(iface, newSize);
    if (FAILED(res))
      return res;
  }

  /*
   * Depending on the type of chain that was opened when the stream was constructed,
   * we delegate the work to the method that readwrites to the block chains.
   */
  if (This->smallBlockChain!=0)
  {
    res = SmallBlockChainStream_WriteAt(This->smallBlockChain,
				  This->currentPosition,
				  cb,
				  pv,
				  pcbWritten);

  }
  else if (This->bigBlockChain!=0)
  {
    res = BlockChainStream_WriteAt(This->bigBlockChain,
			     This->currentPosition,
			     cb,
			     pv,
			     pcbWritten);
  }
  else
  {
    /* this should never happen because the IStream_SetSize call above will
     * make sure a big or small block chain is created */
    assert(FALSE);
    res = 0;
  }

  /*
   * Advance the position pointer for the number of positions written.
   */
  This->currentPosition.u.LowPart += *pcbWritten;

  TRACE("<-- S_OK, written %u\n", *pcbWritten);
  return res;
}

/***
 * 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 StgStreamImpl_Seek(
		  IStream*      iface,
		  LARGE_INTEGER   dlibMove,         /* [in] */
		  DWORD           dwOrigin,         /* [in] */
		  ULARGE_INTEGER* plibNewPosition) /* [out] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

  ULARGE_INTEGER newPosition;

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

  /*
   * fail if the stream has no parent (as does windows)
   */

  if (!This->parentStorage)
  {
    WARN("storage reverted\n");
    return STG_E_REVERTED;
  }

  /*
   * The caller is allowed to pass in NULL as the new position return value.
   * If it happens, we assign it to a dynamic variable to avoid special cases
   * in the code below.
   */
  if (plibNewPosition == 0)
  {
    plibNewPosition = &newPosition;
  }

  /*
   * The file pointer is moved depending on the given "function"
   * parameter.
   */
  switch (dwOrigin)
  {