stg_stream.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

    case STREAM_SEEK_SET:
      plibNewPosition->u.HighPart = 0;
      plibNewPosition->u.LowPart  = 0;
      break;
    case STREAM_SEEK_CUR:
      *plibNewPosition = This->currentPosition;
      break;
    case STREAM_SEEK_END:
      *plibNewPosition = This->streamSize;
      break;
    default:
      WARN("invalid dwOrigin %d\n", dwOrigin);
      return STG_E_INVALIDFUNCTION;
  }

  plibNewPosition->QuadPart = RtlLargeIntegerAdd( plibNewPosition->QuadPart, dlibMove.QuadPart );

  /*
   * tell the caller what we calculated
   */
  This->currentPosition = *plibNewPosition;

  return S_OK;
}

/***
 * This method is part of the IStream interface.
 *
 * It will change the size of a stream.
 *
 * TODO: Switch from small blocks to big blocks and vice versa.
 *
 * See the documentation of IStream for more info.
 */
static HRESULT WINAPI StgStreamImpl_SetSize(
				     IStream*      iface,
				     ULARGE_INTEGER  libNewSize)   /* [in] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

  StgProperty    curProperty;
  BOOL         Success;

  TRACE("(%p, %d)\n", iface, libNewSize.u.LowPart);

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

  /*
   * As documented.
   */
  if (libNewSize.u.HighPart != 0)
  {
    WARN("invalid value for libNewSize.u.HighPart %d\n", libNewSize.u.HighPart);
    return STG_E_INVALIDFUNCTION;
  }

  /*
   * Do we have permission?
   */
  if (!(This->grfMode & (STGM_WRITE | STGM_READWRITE)))
  {
    WARN("access denied\n");
    return STG_E_ACCESSDENIED;
  }

  if (This->streamSize.u.LowPart == libNewSize.u.LowPart)
    return S_OK;

  /*
   * This will happen if we're creating a stream
   */
  if ((This->smallBlockChain == 0) && (This->bigBlockChain == 0))
  {
    if (libNewSize.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);
    }
  }

  /*
   * Read this stream's property to see if it's small blocks or big blocks
   */
  Success = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
                                       This->ownerProperty,
                                       &curProperty);
  /*
   * Determine if we have to switch from small to big blocks or vice versa
   */
  if ( (This->smallBlockChain!=0) &&
       (curProperty.size.u.LowPart < LIMIT_TO_USE_SMALL_BLOCK) )
  {
    if (libNewSize.u.LowPart >= LIMIT_TO_USE_SMALL_BLOCK)
    {
      /*
       * Transform the small block chain into a big block chain
       */
      This->bigBlockChain = Storage32Impl_SmallBlocksToBigBlocks(
                                This->parentStorage->ancestorStorage,
                                &This->smallBlockChain);
    }
  }

  if (This->smallBlockChain!=0)
  {
    Success = SmallBlockChainStream_SetSize(This->smallBlockChain, libNewSize);
  }
  else
  {
    Success = BlockChainStream_SetSize(This->bigBlockChain, libNewSize);
  }

  /*
   * Write the new information about this stream to the property
   */
  Success = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
                                       This->ownerProperty,
                                       &curProperty);

  curProperty.size.u.HighPart = libNewSize.u.HighPart;
  curProperty.size.u.LowPart = libNewSize.u.LowPart;

  if (Success)
  {
    StorageImpl_WriteProperty(This->parentStorage->ancestorStorage,
				This->ownerProperty,
				&curProperty);
  }

  This->streamSize = libNewSize;

  return S_OK;
}

/***
 * This method is part of the IStream interface.
 *
 * It will copy the 'cb' Bytes to 'pstm' IStream.
 *
 * See the documentation of IStream for more info.
 */
static HRESULT WINAPI StgStreamImpl_CopyTo(
				    IStream*      iface,
				    IStream*      pstm,         /* [unique][in] */
				    ULARGE_INTEGER  cb,           /* [in] */
				    ULARGE_INTEGER* pcbRead,      /* [out] */
				    ULARGE_INTEGER* pcbWritten)   /* [out] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;
  HRESULT        hr = S_OK;
  BYTE           tmpBuffer[128];
  ULONG          bytesRead, bytesWritten, copySize;
  ULARGE_INTEGER totalBytesRead;
  ULARGE_INTEGER totalBytesWritten;

  TRACE("(%p, %p, %d, %p, %p)\n",
	iface, pstm, cb.u.LowPart, pcbRead, pcbWritten);

  /*
   * Sanity check
   */

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

  if ( pstm == 0 )
    return STG_E_INVALIDPOINTER;

  totalBytesRead.u.LowPart = totalBytesRead.u.HighPart = 0;
  totalBytesWritten.u.LowPart = totalBytesWritten.u.HighPart = 0;

  /*
   * use stack to store data temporarily
   * there is surely a more performant way of doing it, for now this basic
   * implementation will do the job
   */
  while ( cb.u.LowPart > 0 )
  {
    if ( cb.u.LowPart >= 128 )
      copySize = 128;
    else
      copySize = cb.u.LowPart;

    IStream_Read(iface, tmpBuffer, copySize, &bytesRead);

    totalBytesRead.u.LowPart += bytesRead;

    IStream_Write(pstm, tmpBuffer, bytesRead, &bytesWritten);

    totalBytesWritten.u.LowPart += bytesWritten;

    /*
     * Check that read & write operations were successful
     */
    if (bytesRead != bytesWritten)
    {
      hr = STG_E_MEDIUMFULL;
      WARN("medium full\n");
      break;
    }

    if (bytesRead!=copySize)
      cb.u.LowPart = 0;
    else
      cb.u.LowPart -= bytesRead;
  }

  /*
   * Update number of bytes read and written
   */
  if (pcbRead)
  {
    pcbRead->u.LowPart = totalBytesRead.u.LowPart;
    pcbRead->u.HighPart = totalBytesRead.u.HighPart;
  }

  if (pcbWritten)
  {
    pcbWritten->u.LowPart = totalBytesWritten.u.LowPart;
    pcbWritten->u.HighPart = totalBytesWritten.u.HighPart;
  }
  return hr;
}

/***
 * This method is part of the IStream interface.
 *
 * For streams contained in structured storages, this method
 * does nothing. This is what the documentation tells us.
 *
 * See the documentation of IStream for more info.
 */
static HRESULT WINAPI StgStreamImpl_Commit(
		  IStream*      iface,
		  DWORD           grfCommitFlags)  /* [in] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

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

  return S_OK;
}

/***
 * This method is part of the IStream interface.
 *
 * For streams contained in structured storages, this method
 * does nothing. This is what the documentation tells us.
 *
 * See the documentation of IStream for more info.
 */
static HRESULT WINAPI StgStreamImpl_Revert(
		  IStream* iface)
{
  return S_OK;
}

static HRESULT WINAPI StgStreamImpl_LockRegion(
					IStream*     iface,
					ULARGE_INTEGER libOffset,   /* [in] */
					ULARGE_INTEGER cb,          /* [in] */
					DWORD          dwLockType)  /* [in] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

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

  FIXME("not implemented!\n");
  return E_NOTIMPL;
}

static HRESULT WINAPI StgStreamImpl_UnlockRegion(
					  IStream*     iface,
					  ULARGE_INTEGER libOffset,   /* [in] */
					  ULARGE_INTEGER cb,          /* [in] */
					  DWORD          dwLockType)  /* [in] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

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

  FIXME("not implemented!\n");
  return E_NOTIMPL;
}

/***
 * This method is part of the IStream interface.
 *
 * This method returns information about the current
 * stream.
 *
 * See the documentation of IStream for more info.
 */
static HRESULT WINAPI StgStreamImpl_Stat(
		  IStream*     iface,
		  STATSTG*       pstatstg,     /* [out] */
		  DWORD          grfStatFlag)  /* [in] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;

  StgProperty    curProperty;
  BOOL         readSuccessful;

  TRACE("%p %p %d\n", This, pstatstg, grfStatFlag);

  /*
   * if stream has no parent, return STG_E_REVERTED
   */

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

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

  if (readSuccessful)
  {
    StorageUtl_CopyPropertyToSTATSTG(pstatstg,
				     &curProperty,
				     grfStatFlag);

    pstatstg->grfMode = This->grfMode;

    return S_OK;
  }

  WARN("failed to read properties\n");
  return E_FAIL;
}

/***
 * This method is part of the IStream interface.
 *
 * This method returns a clone of the interface that allows for
 * another seek pointer
 *
 * See the documentation of IStream for more info.
 *
 * I am not totally sure what I am doing here but I presume that this
 * should be basically as simple as creating a new stream with the same
 * parent etc and positioning its seek cursor.
 */
static HRESULT WINAPI StgStreamImpl_Clone(
				   IStream*     iface,
				   IStream**    ppstm) /* [out] */
{
  StgStreamImpl* const This=(StgStreamImpl*)iface;
  HRESULT hres;
  StgStreamImpl* new_stream;
  LARGE_INTEGER seek_pos;

  TRACE("%p %p\n", This, ppstm);

  /*
   * Sanity check
   */

  if (!This->parentStorage)
    return STG_E_REVERTED;

  if ( ppstm == 0 )
    return STG_E_INVALIDPOINTER;

  new_stream = StgStreamImpl_Construct (This->parentStorage, This->grfMode, This->ownerProperty);

  if (!new_stream)
    return STG_E_INSUFFICIENTMEMORY; /* Currently the only reason for new_stream=0 */

  *ppstm = (IStream*) new_stream;
  IStream_AddRef(*ppstm);

  seek_pos.QuadPart = This->currentPosition.QuadPart;

  hres=StgStreamImpl_Seek (*ppstm, seek_pos, STREAM_SEEK_SET, NULL);

  assert (SUCCEEDED(hres));

  return S_OK;
}

/*
 * Virtual function table for the StgStreamImpl class.
 */
static const IStreamVtbl StgStreamImpl_Vtbl =
{
    StgStreamImpl_QueryInterface,
    StgStreamImpl_AddRef,
    StgStreamImpl_Release,
    StgStreamImpl_Read,
    StgStreamImpl_Write,
    StgStreamImpl_Seek,
    StgStreamImpl_SetSize,
    StgStreamImpl_CopyTo,
    StgStreamImpl_Commit,
    StgStreamImpl_Revert,
    StgStreamImpl_LockRegion,
    StgStreamImpl_UnlockRegion,
    StgStreamImpl_Stat,
    StgStreamImpl_Clone
};

/******************************************************************************
** StgStreamImpl implementation
*/

/***
 * This is the constructor for the StgStreamImpl class.
 *
 * Params:
 *    parentStorage - Pointer to the storage that contains the stream to open
 *    ownerProperty - Index of the property that points to this stream.
 */
StgStreamImpl* StgStreamImpl_Construct(
		StorageBaseImpl* parentStorage,
    DWORD            grfMode,
    ULONG            ownerProperty)
{
  StgStreamImpl* newStream;

  newStream = HeapAlloc(GetProcessHeap(), 0, sizeof(StgStreamImpl));

  if (newStream!=0)
  {
    /*
     * Set-up the virtual function table and reference count.
     */
    newStream->lpVtbl    = &StgStreamImpl_Vtbl;
    newStream->ref       = 0;

    newStream->parentStorage = parentStorage;

    /*
     * We want to nail-down the reference to the storage in case the
     * stream out-lives the storage in the client application.
     *
     * -- IStorage_AddRef((IStorage*)newStream->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)
     */

    newStream->grfMode = grfMode;
    newStream->ownerProperty = ownerProperty;

    /*
     * Start the stream at the beginning.
     */
    newStream->currentPosition.u.HighPart = 0;
    newStream->currentPosition.u.LowPart = 0;

    /*
     * Initialize the rest of the data.
     */
    newStream->streamSize.u.HighPart = 0;
    newStream->streamSize.u.LowPart  = 0;
    newStream->bigBlockChain       = 0;
    newStream->smallBlockChain     = 0;

    /*
     * Read the size from the property and determine if the blocks forming
     * this stream are large or small.
     */
    StgStreamImpl_OpenBlockChain(newStream);

    /* add us to the storage's list of active streams */
    StorageBaseImpl_AddStream(parentStorage, newStream);
  }

  return newStream;
}