ole/stg_stream.c

   1 /*
   2  * Compound Storage (32 bit version)
   3  * Stream implementation
   4  *
   5  * This file contains the implementation of the stream interface
   6  * for streams contained in a compound storage.
   7  *
   8  * Copyright 1999 Francis Beaudet
   9  * Copyright 1999 Thuy Nguyen
  10  */
  11 #include <assert.h>
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <string.h>
  15
  16 #include "winbase.h"
  17 #include "winerror.h"
  18 #include "debug.h"
  19 #include "wine/obj_storage.h"
  20
  21 #include "storage32.h"
  22
  23 DEFAULT_DEBUG_CHANNEL(ole)
  24
  25
  26 /*
  27  * Virtual function table for the StgStreamImpl class.
  28  */
  29 static ICOM_VTABLE(IStream) StgStreamImpl_Vtbl =
  30 {
  31     StgStreamImpl_QueryInterface,
  32     StgStreamImpl_AddRef,
  33     StgStreamImpl_Release,
  34     StgStreamImpl_Read,
  35     StgStreamImpl_Write,
  36     StgStreamImpl_Seek,
  37     StgStreamImpl_SetSize,
  38     StgStreamImpl_CopyTo,
  39     StgStreamImpl_Commit,
  40     StgStreamImpl_Revert,
  41     StgStreamImpl_LockRegion,
  42     StgStreamImpl_UnlockRegion,
  43     StgStreamImpl_Stat,
  44     StgStreamImpl_Clone
  45 };
  46
  47 /******************************************************************************
  48 ** StgStreamImpl implementation
  49 */
  50
  51 /***
  52  * This is the constructor for the StgStreamImpl class.
  53  *
  54  * Params:
  55  *    parentStorage - Pointer to the storage that contains the stream to open
  56  *    ownerProperty - Index of the property that points to this stream.
  57  */
  58 StgStreamImpl* StgStreamImpl_Construct(
  59                 StorageBaseImpl* parentStorage,
  60                 ULONG              ownerProperty)
  61 {
  62   StgStreamImpl* newStream;
  63
  64   newStream = HeapAlloc(GetProcessHeap(), 0, sizeof(StgStreamImpl));
  65
  66   if (newStream!=0)
  67   {
  68     /*
  69      * Set-up the virtual function table and reference count.
  70      */
  71     newStream->lpvtbl = &StgStreamImpl_Vtbl;
  72     newStream->ref    = 0;
  73
  74     /*
  75      * We want to nail-down the reference to the storage in case the
  76      * stream out-lives the storage in the client application.
  77      */
  78     newStream->parentStorage = parentStorage;
  79     IStorage_AddRef((IStorage*)newStream->parentStorage);
  80
  81     newStream->ownerProperty = ownerProperty;
  82
  83     /*
  84      * Start the stream at the begining.
  85      */
  86     newStream->currentPosition.HighPart = 0;
  87     newStream->currentPosition.LowPart = 0;
  88
  89     /*
  90      * Initialize the rest of the data.
  91      */
  92     newStream->streamSize.HighPart = 0;
  93     newStream->streamSize.LowPart  = 0;
  94     newStream->bigBlockChain       = 0;
  95     newStream->smallBlockChain     = 0;
  96
  97     /*
  98      * Read the size from the property and determine if the blocks forming
  99      * this stream are large or small.
 100      */
 101     StgStreamImpl_OpenBlockChain(newStream);
 102   }
 103
 104   return newStream;
 105 }
 106
 107 /***
 108  * This is the destructor of the StgStreamImpl class.
 109  *
 110  * This method will clean-up all the resources used-up by the given StgStreamImpl
 111  * class. The pointer passed-in to this function will be freed and will not
 112  * be valid anymore.
 113  */
 114 void StgStreamImpl_Destroy(StgStreamImpl* This)
 115 {
 116   /*
 117    * Release the reference we are holding on the parent storage.
 118    */
 119   IStorage_Release((IStorage*)This->parentStorage);
 120   This->parentStorage = 0;
 121
 122   /*
 123    * Make sure we clean-up the block chain stream objects that we were using.
 124    */
 125   if (This->bigBlockChain != 0)
 126   {
 127     BlockChainStream_Destroy(This->bigBlockChain);
 128     This->bigBlockChain = 0;
 129   }
 130
 131   if (This->smallBlockChain != 0)
 132   {
 133     SmallBlockChainStream_Destroy(This->smallBlockChain);
 134     This->smallBlockChain = 0;
 135   }
 136
 137   /*
 138    * Finally, free the memory used-up by the class.
 139    */
 140   HeapFree(GetProcessHeap(), 0, This);
 141 }
 142
 143 /***
 144  * This implements the IUnknown method QueryInterface for this
 145  * class
 146  */
 147 HRESULT WINAPI StgStreamImpl_QueryInterface(
 148                   IStream*     iface,
 149                   REFIID         riid,        /* [in] */
 150                   void**         ppvObject)   /* [iid_is][out] */
 151 {
 152   StgStreamImpl* const This=(StgStreamImpl*)iface;
 153
 154   /*
 155    * Perform a sanity check on the parameters.
 156    */
 157   if (ppvObject==0)
 158     return E_INVALIDARG;
 159
 160   /*
 161    * Initialize the return parameter.
 162    */
 163   *ppvObject = 0;
 164
 165   /*
 166    * Compare the riid with the interface IDs implemented by this object.
 167    */
 168   if (memcmp(&IID_IUnknown, riid, sizeof(IID_IUnknown)) == 0)
 169   {
 170     *ppvObject = (IStream*)This;
 171   }
 172   else if (memcmp(&IID_IStorage, riid, sizeof(IID_IStream)) == 0)
 173   {
 174     *ppvObject = (IStream*)This;
 175   }
 176
 177   /*
 178    * Check that we obtained an interface.
 179    */
 180   if ((*ppvObject)==0)
 181     return E_NOINTERFACE;
 182
 183   /*
 184    * Query Interface always increases the reference count by one when it is
 185    * successful
 186    */
 187   StgStreamImpl_AddRef(iface);
 188
 189   return S_OK;;
 190 }
 191
 192 /***
 193  * This implements the IUnknown method AddRef for this
 194  * class
 195  */
 196 ULONG WINAPI StgStreamImpl_AddRef(
 197                 IStream* iface)
 198 {
 199   StgStreamImpl* const This=(StgStreamImpl*)iface;
 200
 201   This->ref++;
 202
 203   return This->ref;
 204 }
 205
 206 /***
 207  * This implements the IUnknown method Release for this
 208  * class
 209  */
 210 ULONG WINAPI StgStreamImpl_Release(
 211                 IStream* iface)
 212 {
 213   StgStreamImpl* const This=(StgStreamImpl*)iface;
 214
 215   ULONG newRef;
 216
 217   This->ref--;
 218
 219   newRef = This->ref;
 220
 221   /*
 222    * If the reference count goes down to 0, perform suicide.
 223    */
 224   if (newRef==0)
 225   {
 226     StgStreamImpl_Destroy(This);
 227   }
 228
 229   return newRef;
 230 }
 231
 232 /***
 233  * This method will open the block chain pointed by the property
 234  * that describes the stream.
 235  * If the stream's size is null, no chain is opened.
 236  */
 237 void StgStreamImpl_OpenBlockChain(
 238         StgStreamImpl* This)
 239 {
 240   StgProperty    curProperty;
 241   BOOL         readSucessful;
 242
 243   /*
 244    * Make sure no old object is staying behind.
 245    */
 246   if (This->smallBlockChain != 0)
 247   {
 248     SmallBlockChainStream_Destroy(This->smallBlockChain);
 249     This->smallBlockChain = 0;
 250   }
 251
 252   if (This->bigBlockChain != 0)
 253   {
 254     BlockChainStream_Destroy(This->bigBlockChain);
 255     This->bigBlockChain = 0;
 256   }
 257
 258   /*
 259    * Read the information from the property.
 260    */
 261   readSucessful = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 262                                              This->ownerProperty,
 263                                              &curProperty);
 264
 265   if (readSucessful)
 266   {
 267     This->streamSize = curProperty.size;
 268
 269     /*
 270      * This code supports only streams that are <32 bits in size.
 271      */
 272     assert(This->streamSize.HighPart == 0);
 273
 274     if(curProperty.startingBlock == BLOCK_END_OF_CHAIN)
 275     {
 276       assert( (This->streamSize.HighPart == 0) && (This->streamSize.LowPart == 0) );
 277     }
 278     else
 279     {
 280       if ( (This->streamSize.HighPart == 0) &&
 281            (This->streamSize.LowPart < LIMIT_TO_USE_SMALL_BLOCK) )
 282       {
 283         This->smallBlockChain = SmallBlockChainStream_Construct(
 284                                                                 This->parentStorage->ancestorStorage,
 285                                                                 This->ownerProperty);
 286       }
 287       else
 288       {
 289         This->bigBlockChain = BlockChainStream_Construct(
 290                                                          This->parentStorage->ancestorStorage,
 291                                                          NULL,
 292                                                          This->ownerProperty);
 293       }
 294     }
 295   }
 296 }
 297
 298 /***
 299  * This method is part of the ISequentialStream interface.
 300  *
 301  * If reads a block of information from the stream at the current
 302  * position. It then moves the current position at the end of the
 303  * read block
 304  *
 305  * See the documentation of ISequentialStream for more info.
 306  */
 307 HRESULT WINAPI StgStreamImpl_Read(
 308                   IStream*     iface,
 309                   void*          pv,        /* [length_is][size_is][out] */
 310                   ULONG          cb,        /* [in] */
 311                   ULONG*         pcbRead)   /* [out] */
 312 {
 313   StgStreamImpl* const This=(StgStreamImpl*)iface;
 314
 315   ULONG bytesReadBuffer;
 316   ULONG bytesToReadFromBuffer;
 317
 318   /*
 319    * If the caller is not interested in the nubmer of bytes read,
 320    * we use another buffer to avoid "if" statements in the code.
 321    */
 322   if (pcbRead==0)
 323     pcbRead = &bytesReadBuffer;
 324
 325   /*
 326    * Using the known size of the stream, calculate the number of bytes
 327    * to read from the block chain
 328    */
 329   bytesToReadFromBuffer = MIN( This->streamSize.LowPart - This->currentPosition.LowPart, cb);
 330
 331   /*
 332    * Depending on the type of chain that was opened when the stream was constructed,
 333    * we delegate the work to the method that read the block chains.
 334    */
 335   if (This->smallBlockChain!=0)
 336   {
 337     SmallBlockChainStream_ReadAt(This->smallBlockChain,
 338                                  This->currentPosition,
 339                                  bytesToReadFromBuffer,
 340                                  pv,
 341                                  pcbRead);
 342
 343   }
 344   else if (This->bigBlockChain!=0)
 345   {
 346     BlockChainStream_ReadAt(This->bigBlockChain,
 347                             This->currentPosition,
 348                             bytesToReadFromBuffer,
 349                             pv,
 350                             pcbRead);
 351   }
 352   else
 353     assert(FALSE);
 354
 355   /*
 356    * We should always be able to read the proper amount of data from the
 357    * chain.
 358    */
 359   assert(bytesToReadFromBuffer == *pcbRead);
 360
 361   /*
 362    * Advance the pointer for the number of positions read.
 363    */
 364   This->currentPosition.LowPart += *pcbRead;
 365
 366   /*
 367    * The function returns S_OK if the buffer was filled completely
 368    * it returns S_FALSE if the end of the stream is reached before the
 369    * buffer is filled
 370    */
 371   if(*pcbRead == cb)
 372     return S_OK;
 373
 374   return S_FALSE;
 375 }
 376
 377 /***
 378  * This method is part of the ISequentialStream interface.
 379  *
 380  * It writes a block of information to the stream at the current
 381  * position. It then moves the current position at the end of the
 382  * written block. If the stream is too small to fit the block,
 383  * the stream is grown to fit.
 384  *
 385  * See the documentation of ISequentialStream for more info.
 386  */
 387 HRESULT WINAPI StgStreamImpl_Write(
 388                   IStream*     iface,
 389                   const void*    pv,          /* [size_is][in] */
 390                   ULONG          cb,          /* [in] */
 391                   ULONG*         pcbWritten)  /* [out] */
 392 {
 393   StgStreamImpl* const This=(StgStreamImpl*)iface;
 394
 395   ULARGE_INTEGER newSize;
 396   ULONG bytesWritten = 0;
 397
 398   /*
 399    * If the caller is not interested in the number of bytes written,
 400    * we use another buffer to avoid "if" statements in the code.
 401    */
 402   if (pcbWritten == 0)
 403     pcbWritten = &bytesWritten;
 404
 405   if (cb == 0)
 406   {
 407     return S_OK;
 408   }
 409   else
 410   {
 411     newSize.HighPart = 0;
 412     newSize.LowPart = This->currentPosition.LowPart + cb;
 413   }
 414
 415   /*
 416    * Verify if we need to grow the stream
 417    */
 418   if (newSize.LowPart > This->streamSize.LowPart)
 419   {
 420     /* grow stream */
 421     StgStreamImpl_SetSize(iface, newSize);
 422   }
 423
 424   /*
 425    * Depending on the type of chain that was opened when the stream was constructed,
 426    * we delegate the work to the method that readwrites to the block chains.
 427    */
 428   if (This->smallBlockChain!=0)
 429   {
 430     SmallBlockChainStream_WriteAt(This->smallBlockChain,
 431                                   This->currentPosition,
 432                                   cb,
 433                                   pv,
 434                                   pcbWritten);
 435
 436   }
 437   else if (This->bigBlockChain!=0)
 438   {
 439     BlockChainStream_WriteAt(This->bigBlockChain,
 440                              This->currentPosition,
 441                              cb,
 442                              pv,
 443                              pcbWritten);
 444   }
 445   else
 446     assert(FALSE);
 447
 448   /*
 449    * Advance the position pointer for the number of positions written.
 450    */
 451   This->currentPosition.LowPart += *pcbWritten;
 452
 453   return S_OK;
 454 }
 455
 456 /***
 457  * This method is part of the IStream interface.
 458  *
 459  * It will move the current stream pointer according to the parameters
 460  * given.
 461  *
 462  * See the documentation of IStream for more info.
 463  */
 464 HRESULT WINAPI StgStreamImpl_Seek(
 465                   IStream*      iface,
 466                   LARGE_INTEGER   dlibMove,         /* [in] */
 467                   DWORD           dwOrigin,         /* [in] */
 468                   ULARGE_INTEGER* plibNewPosition) /* [out] */
 469 {
 470   StgStreamImpl* const This=(StgStreamImpl*)iface;
 471
 472   ULARGE_INTEGER newPosition;
 473
 474   /*
 475    * The caller is allowed to pass in NULL as the new position return value.
 476    * If it happens, we assign it to a dynamic variable to avoid special cases
 477    * in the code below.
 478    */
 479   if (plibNewPosition == 0)
 480   {
 481     plibNewPosition = &newPosition;
 482   }
 483
 484   /*
 485    * The file pointer is moved depending on the given "function"
 486    * parameter.
 487    */
 488   switch (dwOrigin)
 489   {
 490     case STREAM_SEEK_SET:
 491       plibNewPosition->HighPart = 0;
 492       plibNewPosition->LowPart  = 0;
 493       break;
 494     case STREAM_SEEK_CUR:
 495       *plibNewPosition = This->currentPosition;
 496       break;
 497     case STREAM_SEEK_END:
 498       *plibNewPosition = This->streamSize;
 499       break;
 500     default:
 501       return STG_E_INVALIDFUNCTION;
 502   }
 503
 504   /*
 505    * We don't support files with offsets of 64 bits.
 506    */
 507   assert(dlibMove.HighPart == 0);
 508
 509   /*
 510    * Check if we end-up before the beginning of the file. That should trigger an
 511    * error.
 512    */
 513   if ( (dlibMove.LowPart<0) && (plibNewPosition->LowPart < (ULONG)(-dlibMove.LowPart)) )
 514   {
 515     /*
 516      * I don't know what error to send there.
 517      */
 518     return E_FAIL;
 519   }
 520
 521   /*
 522    * Move the actual file pointer
 523    * If the file pointer ends-up after the end of the stream, the next Write operation will
 524    * make the file larger. This is how it is documented.
 525    */
 526   plibNewPosition->LowPart += dlibMove.LowPart;
 527   This->currentPosition = *plibNewPosition;
 528
 529   return S_OK;
 530 }
 531
 532 /***
 533  * This method is part of the IStream interface.
 534  *
 535  * It will change the size of a stream.
 536  *
 537  * TODO: Switch from small blocks to big blocks and vice versa.
 538  *
 539  * See the documentation of IStream for more info.
 540  */
 541 HRESULT WINAPI StgStreamImpl_SetSize(
 542                                      IStream*      iface,
 543                                      ULARGE_INTEGER  libNewSize)   /* [in] */
 544 {
 545   StgStreamImpl* const This=(StgStreamImpl*)iface;
 546
 547   StgProperty    curProperty;
 548   BOOL         Success;
 549
 550   /*
 551    * As documented.
 552    */
 553   if (libNewSize.HighPart != 0)
 554     return STG_E_INVALIDFUNCTION;
 555
 556   if (This->streamSize.LowPart == libNewSize.LowPart)
 557     return S_OK;
 558
 559   /*
 560    * This will happen if we're creating a stream
 561    */
 562   if ((This->smallBlockChain == 0) && (This->bigBlockChain == 0))
 563   {
 564     if (libNewSize.LowPart < LIMIT_TO_USE_SMALL_BLOCK)
 565     {
 566       This->smallBlockChain = SmallBlockChainStream_Construct(
 567                                     This->parentStorage->ancestorStorage,
 568                                     This->ownerProperty);
 569     }
 570     else
 571     {
 572       This->bigBlockChain = BlockChainStream_Construct(
 573                                 This->parentStorage->ancestorStorage,
 574                                 NULL,
 575                                 This->ownerProperty);
 576     }
 577   }
 578
 579   /*
 580    * Read this stream's property to see if it's small blocks or big blocks
 581    */
 582   Success = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 583                                        This->ownerProperty,
 584                                        &curProperty);
 585   /*
 586    * Determine if we have to switch from small to big blocks or vice versa
 587    */
 588
 589   if (curProperty.size.LowPart < LIMIT_TO_USE_SMALL_BLOCK)
 590   {
 591     if (libNewSize.LowPart >= LIMIT_TO_USE_SMALL_BLOCK)
 592     {
 593       /*
 594        * Transform the small block chain into a big block chain
 595        */
 596       This->bigBlockChain = Storage32Impl_SmallBlocksToBigBlocks(
 597                                 This->parentStorage->ancestorStorage,
 598                                 &This->smallBlockChain);
 599     }
 600   }
 601
 602   if (This->smallBlockChain!=0)
 603   {
 604     Success = SmallBlockChainStream_SetSize(This->smallBlockChain, libNewSize);
 605   }
 606   else
 607   {
 608     Success = BlockChainStream_SetSize(This->bigBlockChain, libNewSize);
 609   }
 610
 611   /*
 612    * Write to the property the new information about this stream
 613    */
 614   Success = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 615                                        This->ownerProperty,
 616                                        &curProperty);
 617
 618   curProperty.size.HighPart = libNewSize.HighPart;
 619   curProperty.size.LowPart = libNewSize.LowPart;
 620
 621   if (Success)
 622   {
 623     StorageImpl_WriteProperty(This->parentStorage->ancestorStorage,
 624                                 This->ownerProperty,
 625                                 &curProperty);
 626   }
 627
 628   This->streamSize = libNewSize;
 629
 630   return S_OK;
 631 }
 632
 633 /***
 634  * This method is part of the IStream interface.
 635  *
 636  * It will copy the 'cb' Bytes to 'pstm' IStream.
 637  *
 638  * See the documentation of IStream for more info.
 639  */
 640 HRESULT WINAPI StgStreamImpl_CopyTo(
 641                                     IStream*      iface,
 642                                     IStream*      pstm,         /* [unique][in] */
 643                                     ULARGE_INTEGER  cb,           /* [in] */
 644                                     ULARGE_INTEGER* pcbRead,      /* [out] */
 645                                     ULARGE_INTEGER* pcbWritten)   /* [out] */
 646 {
 647   StgStreamImpl* const This=(StgStreamImpl*)iface;
 648   HRESULT        hr = S_OK;
 649   BYTE           tmpBuffer[128];
 650   ULONG          bytesRead, bytesWritten, copySize;
 651   ULARGE_INTEGER totalBytesRead;
 652   ULARGE_INTEGER totalBytesWritten;
 653
 654   /*
 655    * Sanity check
 656    */
 657   if ( pstm == 0 )
 658     return STG_E_INVALIDPOINTER;
 659
 660   totalBytesRead.LowPart = totalBytesRead.HighPart = 0;
 661   totalBytesWritten.LowPart = totalBytesWritten.HighPart = 0;
 662
 663   /*
 664    * use stack to store data temporarly
 665    * there is surely more performant way of doing it, for now this basic
 666    * implementation will do the job
 667    */
 668   while ( cb.LowPart > 0 )
 669   {
 670     if ( cb.LowPart >= 128 )
 671       copySize = 128;
 672     else
 673       copySize = cb.LowPart;
 674
 675     StgStreamImpl_Read(iface, tmpBuffer, 128, &bytesRead);
 676
 677     totalBytesRead.LowPart += bytesRead;
 678
 679     StgStreamImpl_Write(pstm, tmpBuffer, bytesRead, &bytesWritten);
 680
 681     totalBytesWritten.LowPart += bytesWritten;
 682
 683     /*
 684      * Check that read & write operations were succesfull
 685      */
 686     if ( (bytesRead != copySize) && (bytesWritten != copySize) )
 687     {
 688       hr = STG_E_MEDIUMFULL;
 689       break;
 690     }
 691
 692     cb.LowPart = cb.LowPart - copySize;
 693   }
 694
 695   /*
 696    * Update number of bytes read and written
 697    */
 698   if (pcbRead)
 699   {
 700     pcbRead->LowPart = totalBytesRead.LowPart;
 701     pcbRead->HighPart = totalBytesRead.HighPart;
 702   }
 703
 704   if (pcbWritten)
 705   {
 706     pcbWritten->LowPart = totalBytesWritten.LowPart;
 707     pcbWritten->HighPart = totalBytesWritten.HighPart;
 708   }
 709   return hr;
 710 }
 711
 712 /***
 713  * This method is part of the IStream interface.
 714  *
 715  * For streams contained in structured storages, this method
 716  * does nothing. This is what the documentation tells us.
 717  *
 718  * See the documentation of IStream for more info.
 719  */
 720 HRESULT WINAPI StgStreamImpl_Commit(
 721                   IStream*      iface,
 722                   DWORD           grfCommitFlags)  /* [in] */
 723 {
 724   return S_OK;
 725 }
 726
 727 /***
 728  * This method is part of the IStream interface.
 729  *
 730  * For streams contained in structured storages, this method
 731  * does nothing. This is what the documentation tells us.
 732  *
 733  * See the documentation of IStream for more info.
 734  */
 735 HRESULT WINAPI StgStreamImpl_Revert(
 736                   IStream* iface)
 737 {
 738   return S_OK;
 739 }
 740
 741 HRESULT WINAPI StgStreamImpl_LockRegion(
 742                                         IStream*     iface,
 743                                         ULARGE_INTEGER libOffset,   /* [in] */
 744                                         ULARGE_INTEGER cb,          /* [in] */
 745                                         DWORD          dwLockType)  /* [in] */
 746 {
 747   FIXME(ole, "not implemented!\n");
 748   return E_NOTIMPL;
 749 }
 750
 751 HRESULT WINAPI StgStreamImpl_UnlockRegion(
 752                                           IStream*     iface,
 753                                           ULARGE_INTEGER libOffset,   /* [in] */
 754                                           ULARGE_INTEGER cb,          /* [in] */
 755                                           DWORD          dwLockType)  /* [in] */
 756 {
 757   FIXME(ole, "not implemented!\n");
 758   return E_NOTIMPL;
 759 }
 760
 761 /***
 762  * This method is part of the IStream interface.
 763  *
 764  * This method returns information about the current
 765  * stream.
 766  *
 767  * See the documentation of IStream for more info.
 768  */
 769 HRESULT WINAPI StgStreamImpl_Stat(
 770                   IStream*     iface,
 771                   STATSTG*       pstatstg,     /* [out] */
 772                   DWORD          grfStatFlag)  /* [in] */
 773 {
 774   StgStreamImpl* const This=(StgStreamImpl*)iface;
 775
 776   StgProperty    curProperty;
 777   BOOL         readSucessful;
 778
 779   /*
 780    * Read the information from the property.
 781    */
 782   readSucessful = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 783                                              This->ownerProperty,
 784                                              &curProperty);
 785
 786   if (readSucessful)
 787   {
 788     StorageUtl_CopyPropertyToSTATSTG(pstatstg,
 789                                      &curProperty,
 790                                      grfStatFlag);
 791
 792     return S_OK;
 793   }
 794
 795   return E_FAIL;
 796 }
 797
 798 HRESULT WINAPI StgStreamImpl_Clone(
 799                                    IStream*     iface,
 800                                    IStream**    ppstm) /* [out] */
 801 {
 802   FIXME(ole, "not implemented!\n");
 803   return E_NOTIMPL;
 804 }