git.oblomov.eu Git - wine/blob - dlls/ole32/stg_bigblockfile.c

   1 /******************************************************************************
   2  *
   3  * BigBlockFile
   4  *
   5  * This is the implementation of a file that consists of blocks of
   6  * a predetermined size.
   7  * This class is used in the Compound File implementation of the
   8  * IStorage and IStream interfaces. It provides the functionality
   9  * to read and write any blocks in the file as well as setting and
  10  * obtaining the size of the file.
  11  * The blocks are indexed sequentially from the start of the file
  12  * starting with -1.
  13  *
  14  * TODO:
  15  * - Support for a transacted mode
  16  *
  17  * Copyright 1999 Thuy Nguyen
  18  *
  19  * This library is free software; you can redistribute it and/or
  20  * modify it under the terms of the GNU Lesser General Public
  21  * License as published by the Free Software Foundation; either
  22  * version 2.1 of the License, or (at your option) any later version.
  23  *
  24  * This library is distributed in the hope that it will be useful,
  25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  27  * Lesser General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU Lesser General Public
  30  * License along with this library; if not, write to the Free Software
  31  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  32  */
  33
  34 #include <assert.h>
  35 #include <stdlib.h>
  36 #include <stdio.h>
  37 #include <string.h>
  38 #include <limits.h>
  39
  40 #include "winbase.h"
  41 #include "winerror.h"
  42 #include "wine/obj_base.h"
  43 #include "wine/obj_storage.h"
  44 #include "ole2.h"
  45
  46 #include "storage32.h"
  47
  48 #include "wine/debug.h"
  49
  50 WINE_DEFAULT_DEBUG_CHANNEL(storage);
  51
  52 /***********************************************************
  53  * Data structures used internally by the BigBlockFile
  54  * class.
  55  */
  56
  57 /* We map in PAGE_SIZE-sized chunks. Must be a multiple of 4096. */
  58 #define PAGE_SIZE       131072
  59
  60 #define BLOCKS_PER_PAGE (PAGE_SIZE / BIG_BLOCK_SIZE)
  61
  62 /* We keep a list of recently-discarded pages. This controls the
  63  * size of that list. */
  64 #define MAX_VICTIM_PAGES 16
  65
  66 /* This structure provides one bit for each block in a page.
  67  * Use BIGBLOCKFILE_{Test,Set,Clear}Bit to manipulate it. */
  68 typedef struct
  69 {
  70     unsigned int bits[BLOCKS_PER_PAGE / (CHAR_BIT * sizeof(unsigned int))];
  71 } BlockBits;
  72
  73 /***
  74  * This structure identifies the paged that are mapped
  75  * from the file and their position in memory. It is
  76  * also used to hold a reference count to those pages.
  77  *
  78  * page_index identifies which PAGE_SIZE chunk from the
  79  * file this mapping represents. (The mappings are always
  80  * PAGE_SIZE-aligned.)
  81  */
  82 struct MappedPage
  83 {
  84     MappedPage *next;
  85     MappedPage *prev;
  86
  87     DWORD  page_index;
  88     LPVOID lpBytes;
  89     LONG   refcnt;
  90
  91     BlockBits readable_blocks;
  92     BlockBits writable_blocks;
  93 };
  94
  95 /***********************************************************
  96  * Prototypes for private methods
  97  */
  98 static void*     BIGBLOCKFILE_GetMappedView(LPBIGBLOCKFILE This,
  99                                             DWORD          page_index);
 100 static void      BIGBLOCKFILE_ReleaseMappedPage(LPBIGBLOCKFILE This,
 101                                                 MappedPage *page);
 102 static void      BIGBLOCKFILE_FreeAllMappedPages(LPBIGBLOCKFILE This);
 103 static void      BIGBLOCKFILE_UnmapAllMappedPages(LPBIGBLOCKFILE This);
 104 static void      BIGBLOCKFILE_RemapAllMappedPages(LPBIGBLOCKFILE This);
 105 static void*     BIGBLOCKFILE_GetBigBlockPointer(LPBIGBLOCKFILE This,
 106                                                  ULONG          index,
 107                                                  DWORD          desired_access);
 108 static MappedPage* BIGBLOCKFILE_GetPageFromPointer(LPBIGBLOCKFILE This,
 109                                                    void*         pBlock);
 110 static MappedPage* BIGBLOCKFILE_CreatePage(LPBIGBLOCKFILE This,
 111                                            ULONG page_index);
 112 static DWORD     BIGBLOCKFILE_GetProtectMode(DWORD openFlags);
 113 static BOOL      BIGBLOCKFILE_FileInit(LPBIGBLOCKFILE This, HANDLE hFile);
 114 static BOOL      BIGBLOCKFILE_MemInit(LPBIGBLOCKFILE This, ILockBytes* plkbyt);
 115
 116 /* Note that this evaluates a and b multiple times, so don't
 117  * pass expressions with side effects. */
 118 #define ROUND_UP(a, b) ((((a) + (b) - 1)/(b))*(b))
 119
 120 /***********************************************************
 121  * Blockbits functions.
 122  */
 123 static inline BOOL BIGBLOCKFILE_TestBit(const BlockBits *bb,
 124                                         unsigned int index)
 125 {
 126     unsigned int array_index = index / (CHAR_BIT * sizeof(unsigned int));
 127     unsigned int bit_index = index % (CHAR_BIT * sizeof(unsigned int));
 128
 129     return bb->bits[array_index] & (1 << bit_index);
 130 }
 131
 132 static inline void BIGBLOCKFILE_SetBit(BlockBits *bb, unsigned int index)
 133 {
 134     unsigned int array_index = index / (CHAR_BIT * sizeof(unsigned int));
 135     unsigned int bit_index = index % (CHAR_BIT * sizeof(unsigned int));
 136
 137     bb->bits[array_index] |= (1 << bit_index);
 138 }
 139
 140 static inline void BIGBLOCKFILE_ClearBit(BlockBits *bb, unsigned int index)
 141 {
 142     unsigned int array_index = index / (CHAR_BIT * sizeof(unsigned int));
 143     unsigned int bit_index = index % (CHAR_BIT * sizeof(unsigned int));
 144
 145     bb->bits[array_index] &= ~(1 << bit_index);
 146 }
 147
 148 static inline void BIGBLOCKFILE_Zero(BlockBits *bb)
 149 {
 150     memset(bb->bits, 0, sizeof(bb->bits));
 151 }
 152
 153 /******************************************************************************
 154  *      BIGBLOCKFILE_Construct
 155  *
 156  * Construct a big block file. Create the file mapping object.
 157  * Create the read only mapped pages list, the writable mapped page list
 158  * and the blocks in use list.
 159  */
 160 BigBlockFile * BIGBLOCKFILE_Construct(
 161   HANDLE   hFile,
 162   ILockBytes* pLkByt,
 163   DWORD    openFlags,
 164   ULONG    blocksize,
 165   BOOL     fileBased)
 166 {
 167   LPBIGBLOCKFILE This;
 168
 169   This = (LPBIGBLOCKFILE)HeapAlloc(GetProcessHeap(), 0, sizeof(BigBlockFile));
 170
 171   if (This == NULL)
 172     return NULL;
 173
 174   This->fileBased = fileBased;
 175
 176   This->flProtect = BIGBLOCKFILE_GetProtectMode(openFlags);
 177
 178   This->blocksize = blocksize;
 179
 180   This->maplist = NULL;
 181   This->victimhead = NULL;
 182   This->victimtail = NULL;
 183   This->num_victim_pages = 0;
 184
 185   if (This->fileBased)
 186   {
 187     if (!BIGBLOCKFILE_FileInit(This, hFile))
 188     {
 189       HeapFree(GetProcessHeap(), 0, This);
 190       return NULL;
 191     }
 192   }
 193   else
 194   {
 195     if (!BIGBLOCKFILE_MemInit(This, pLkByt))
 196     {
 197       HeapFree(GetProcessHeap(), 0, This);
 198       return NULL;
 199     }
 200   }
 201
 202   return This;
 203 }
 204
 205 /******************************************************************************
 206  *      BIGBLOCKFILE_FileInit
 207  *
 208  * Initialize a big block object supported by a file.
 209  */
 210 static BOOL BIGBLOCKFILE_FileInit(LPBIGBLOCKFILE This, HANDLE hFile)
 211 {
 212   This->pLkbyt     = NULL;
 213   This->hbytearray = 0;
 214   This->pbytearray = NULL;
 215
 216   This->hfile = hFile;
 217
 218   if (This->hfile == INVALID_HANDLE_VALUE)
 219     return FALSE;
 220
 221   /* create the file mapping object
 222    */
 223   This->hfilemap = CreateFileMappingA(This->hfile,
 224                                       NULL,
 225                                       This->flProtect,
 226                                       0, 0,
 227                                       NULL);
 228
 229   if (!This->hfilemap)
 230   {
 231     CloseHandle(This->hfile);
 232     return FALSE;
 233   }
 234
 235   This->filesize.s.LowPart = GetFileSize(This->hfile,
 236                                          &This->filesize.s.HighPart);
 237
 238   This->maplist = NULL;
 239
 240   TRACE("file len %lu\n", This->filesize.s.LowPart);
 241
 242   return TRUE;
 243 }
 244
 245 /******************************************************************************
 246  *      BIGBLOCKFILE_MemInit
 247  *
 248  * Initialize a big block object supported by an ILockBytes on HGLOABL.
 249  */
 250 static BOOL BIGBLOCKFILE_MemInit(LPBIGBLOCKFILE This, ILockBytes* plkbyt)
 251 {
 252   This->hfile       = 0;
 253   This->hfilemap    = 0;
 254
 255   /*
 256    * Retrieve the handle to the byte array from the LockByte object.
 257    */
 258   if (GetHGlobalFromILockBytes(plkbyt, &(This->hbytearray)) != S_OK)
 259   {
 260     FIXME("May not be an ILockBytes on HGLOBAL\n");
 261     return FALSE;
 262   }
 263
 264   This->pLkbyt = plkbyt;
 265
 266   /*
 267    * Increment the reference count of the ILockByte object since
 268    * we're keeping a reference to it.
 269    */
 270   ILockBytes_AddRef(This->pLkbyt);
 271
 272   This->filesize.s.LowPart = GlobalSize(This->hbytearray);
 273   This->filesize.s.HighPart = 0;
 274
 275   This->pbytearray = GlobalLock(This->hbytearray);
 276
 277   TRACE("mem on %p len %lu\n", This->pbytearray, This->filesize.s.LowPart);
 278
 279   return TRUE;
 280 }
 281
 282 /******************************************************************************
 283  *      BIGBLOCKFILE_Destructor
 284  *
 285  * Destructor. Clean up, free memory.
 286  */
 287 void BIGBLOCKFILE_Destructor(
 288   LPBIGBLOCKFILE This)
 289 {
 290   BIGBLOCKFILE_FreeAllMappedPages(This);
 291
 292   if (This->fileBased)
 293   {
 294     CloseHandle(This->hfilemap);
 295     CloseHandle(This->hfile);
 296   }
 297   else
 298   {
 299     GlobalUnlock(This->hbytearray);
 300     ILockBytes_Release(This->pLkbyt);
 301   }
 302
 303   /* destroy this
 304    */
 305   HeapFree(GetProcessHeap(), 0, This);
 306 }
 307
 308 /******************************************************************************
 309  *      BIGBLOCKFILE_GetROBigBlock
 310  *
 311  * Returns the specified block in read only mode.
 312  * Will return NULL if the block doesn't exists.
 313  */
 314 void* BIGBLOCKFILE_GetROBigBlock(
 315   LPBIGBLOCKFILE This,
 316   ULONG          index)
 317 {
 318   /*
 319    * block index starts at -1
 320    * translate to zero based index
 321    */
 322   if (index == 0xffffffff)
 323     index = 0;
 324   else
 325     index++;
 326
 327   /*
 328    * validate the block index
 329    *
 330    */
 331   if (This->blocksize * (index + 1)
 332       > ROUND_UP(This->filesize.s.LowPart, This->blocksize))
 333   {
 334     TRACE("out of range %lu vs %lu\n", This->blocksize * (index + 1),
 335           This->filesize.s.LowPart);
 336     return NULL;
 337   }
 338
 339   return BIGBLOCKFILE_GetBigBlockPointer(This, index, FILE_MAP_READ);
 340 }
 341
 342 /******************************************************************************
 343  *      BIGBLOCKFILE_GetBigBlock
 344  *
 345  * Returns the specified block.
 346  * Will grow the file if necessary.
 347  */
 348 void* BIGBLOCKFILE_GetBigBlock(LPBIGBLOCKFILE This, ULONG index)
 349 {
 350   /*
 351    * block index starts at -1
 352    * translate to zero based index
 353    */
 354   if (index == 0xffffffff)
 355     index = 0;
 356   else
 357     index++;
 358
 359   /*
 360    * make sure that the block physically exists
 361    */
 362   if ((This->blocksize * (index + 1)) > This->filesize.s.LowPart)
 363   {
 364     ULARGE_INTEGER newSize;
 365
 366     newSize.s.HighPart = 0;
 367     newSize.s.LowPart = This->blocksize * (index + 1);
 368
 369     BIGBLOCKFILE_SetSize(This, newSize);
 370   }
 371
 372   return BIGBLOCKFILE_GetBigBlockPointer(This, index, FILE_MAP_WRITE);
 373 }
 374
 375 /******************************************************************************
 376  *      BIGBLOCKFILE_ReleaseBigBlock
 377  *
 378  * Releases the specified block.
 379  */
 380 void BIGBLOCKFILE_ReleaseBigBlock(LPBIGBLOCKFILE This, void *pBlock)
 381 {
 382     MappedPage *page;
 383
 384     if (pBlock == NULL)
 385         return;
 386
 387     page = BIGBLOCKFILE_GetPageFromPointer(This, pBlock);
 388
 389     if (page == NULL)
 390         return;
 391
 392     BIGBLOCKFILE_ReleaseMappedPage(This, page);
 393 }
 394
 395 /******************************************************************************
 396  *      BIGBLOCKFILE_SetSize
 397  *
 398  * Sets the size of the file.
 399  *
 400  */
 401 void BIGBLOCKFILE_SetSize(LPBIGBLOCKFILE This, ULARGE_INTEGER newSize)
 402 {
 403   if (This->filesize.s.LowPart == newSize.s.LowPart)
 404     return;
 405
 406   TRACE("from %lu to %lu\n", This->filesize.s.LowPart, newSize.s.LowPart);
 407   /*
 408    * unmap all views, must be done before call to SetEndFile
 409    */
 410   BIGBLOCKFILE_UnmapAllMappedPages(This);
 411
 412   if (This->fileBased)
 413   {
 414     char buf[10];
 415
 416     /*
 417      * close file-mapping object, must be done before call to SetEndFile
 418      */
 419     CloseHandle(This->hfilemap);
 420     This->hfilemap = 0;
 421
 422     /*
 423      * BEGIN HACK
 424      * This fixes a bug when saving through smbfs.
 425      * smbmount a Windows shared directory, save a structured storage file
 426      * to that dir: crash.
 427      *
 428      * The problem is that the SetFilePointer-SetEndOfFile combo below
 429      * doesn't always succeed. The file is not grown. It seems like the
 430      * operation is cached. By doing the WriteFile, the file is actually
 431      * grown on disk.
 432      * This hack is only needed when saving to smbfs.
 433      */
 434     memset(buf, '0', 10);
 435     SetFilePointer(This->hfile, newSize.s.LowPart, NULL, FILE_BEGIN);
 436     WriteFile(This->hfile, buf, 10, NULL, NULL);
 437     /*
 438      * END HACK
 439      */
 440
 441     /*
 442      * set the new end of file
 443      */
 444     SetFilePointer(This->hfile, newSize.s.LowPart, NULL, FILE_BEGIN);
 445     SetEndOfFile(This->hfile);
 446
 447     /*
 448      * re-create the file mapping object
 449      */
 450     This->hfilemap = CreateFileMappingA(This->hfile,
 451                                         NULL,
 452                                         This->flProtect,
 453                                         0, 0,
 454                                         NULL);
 455   }
 456   else
 457   {
 458     GlobalUnlock(This->hbytearray);
 459
 460     /*
 461      * Resize the byte array object.
 462      */
 463     ILockBytes_SetSize(This->pLkbyt, newSize);
 464
 465     /*
 466      * Re-acquire the handle, it may have changed.
 467      */
 468     GetHGlobalFromILockBytes(This->pLkbyt, &This->hbytearray);
 469     This->pbytearray = GlobalLock(This->hbytearray);
 470   }
 471
 472   This->filesize.s.LowPart = newSize.s.LowPart;
 473   This->filesize.s.HighPart = newSize.s.HighPart;
 474
 475   BIGBLOCKFILE_RemapAllMappedPages(This);
 476 }
 477
 478 /******************************************************************************
 479  *      BIGBLOCKFILE_GetSize
 480  *
 481  * Returns the size of the file.
 482  *
 483  */
 484 ULARGE_INTEGER BIGBLOCKFILE_GetSize(LPBIGBLOCKFILE This)
 485 {
 486   return This->filesize;
 487 }
 488
 489 /******************************************************************************
 490  *      BIGBLOCKFILE_AccessCheck     [PRIVATE]
 491  *
 492  * block_index is the index within the page.
 493  */
 494 static BOOL BIGBLOCKFILE_AccessCheck(MappedPage *page, ULONG block_index,
 495                                      DWORD desired_access)
 496 {
 497     assert(block_index < BLOCKS_PER_PAGE);
 498
 499     if (desired_access == FILE_MAP_READ)
 500     {
 501         if (BIGBLOCKFILE_TestBit(&page->writable_blocks, block_index))
 502             return FALSE;
 503
 504         BIGBLOCKFILE_SetBit(&page->readable_blocks, block_index);
 505     }
 506     else
 507     {
 508         assert(desired_access == FILE_MAP_WRITE);
 509
 510         if (BIGBLOCKFILE_TestBit(&page->readable_blocks, block_index))
 511             return FALSE;
 512
 513         BIGBLOCKFILE_SetBit(&page->writable_blocks, block_index);
 514     }
 515
 516     return TRUE;
 517 }
 518
 519 /******************************************************************************
 520  *      BIGBLOCKFILE_GetBigBlockPointer     [PRIVATE]
 521  *
 522  * Returns a pointer to the specified block.
 523  */
 524 static void* BIGBLOCKFILE_GetBigBlockPointer(
 525   LPBIGBLOCKFILE This,
 526   ULONG          block_index,
 527   DWORD          desired_access)
 528 {
 529     DWORD page_index = block_index / BLOCKS_PER_PAGE;
 530     DWORD block_on_page = block_index % BLOCKS_PER_PAGE;
 531
 532     MappedPage *page = BIGBLOCKFILE_GetMappedView(This, page_index);
 533     if (!page || !page->lpBytes) return NULL;
 534
 535     if (!BIGBLOCKFILE_AccessCheck(page, block_on_page, desired_access))
 536     {
 537         BIGBLOCKFILE_ReleaseMappedPage(This, page);
 538         return NULL;
 539     }
 540
 541     return (LPBYTE)page->lpBytes + (block_on_page * This->blocksize);
 542 }
 543
 544 /******************************************************************************
 545  *      BIGBLOCKFILE_GetMappedPageFromPointer     [PRIVATE]
 546  *
 547  * pBlock is a pointer to a block on a page.
 548  * The page has to be on the in-use list. (As oppsed to the victim list.)
 549  *
 550  * Does not increment the usage count.
 551  */
 552 static MappedPage *BIGBLOCKFILE_GetPageFromPointer(LPBIGBLOCKFILE This,
 553                                                    void *pBlock)
 554 {
 555     MappedPage *page;
 556
 557     for (page = This->maplist; page != NULL; page = page->next)
 558     {
 559         if ((LPBYTE)pBlock >= (LPBYTE)page->lpBytes
 560             && (LPBYTE)pBlock <= (LPBYTE)page->lpBytes + PAGE_SIZE)
 561             break;
 562
 563     }
 564
 565     return page;
 566 }
 567
 568 /******************************************************************************
 569  *      BIGBLOCKFILE_FindPageInList      [PRIVATE]
 570  *
 571  */
 572 static MappedPage *BIGBLOCKFILE_FindPageInList(MappedPage *head,
 573                                                ULONG page_index)
 574 {
 575     for (; head != NULL; head = head->next)
 576     {
 577         if (head->page_index == page_index)
 578         {
 579             InterlockedIncrement(&head->refcnt);
 580             break;
 581         }
 582     }
 583
 584     return head;
 585
 586 }
 587
 588 static void BIGBLOCKFILE_UnlinkPage(MappedPage *page)
 589 {
 590     if (page->next) page->next->prev = page->prev;
 591     if (page->prev) page->prev->next = page->next;
 592 }
 593
 594 static void BIGBLOCKFILE_LinkHeadPage(MappedPage **head, MappedPage *page)
 595 {
 596     if (*head) (*head)->prev = page;
 597     page->next = *head;
 598     page->prev = NULL;
 599     *head = page;
 600 }
 601
 602 /******************************************************************************
 603  *      BIGBLOCKFILE_GetMappedView      [PRIVATE]
 604  *
 605  * Gets the page requested if it is already mapped.
 606  * If it's not already mapped, this method will map it
 607  */
 608 static void * BIGBLOCKFILE_GetMappedView(
 609   LPBIGBLOCKFILE This,
 610   DWORD          page_index)
 611 {
 612     MappedPage *page;
 613
 614     page = BIGBLOCKFILE_FindPageInList(This->maplist, page_index);
 615     if (!page)
 616     {
 617         page = BIGBLOCKFILE_FindPageInList(This->victimhead, page_index);
 618         if (page)
 619         {
 620             This->num_victim_pages--;
 621
 622             BIGBLOCKFILE_Zero(&page->readable_blocks);
 623             BIGBLOCKFILE_Zero(&page->writable_blocks);
 624         }
 625     }
 626
 627     if (page)
 628     {
 629         /* If the page is not already at the head of the list, move
 630          * it there. (Also moves pages from victim to main list.) */
 631         if (This->maplist != page)
 632         {
 633             if (This->victimhead == page) This->victimhead = page->next;
 634             if (This->victimtail == page) This->victimtail = page->prev;
 635
 636             BIGBLOCKFILE_UnlinkPage(page);
 637
 638             BIGBLOCKFILE_LinkHeadPage(&This->maplist, page);
 639         }
 640
 641         return page;
 642     }
 643
 644     page = BIGBLOCKFILE_CreatePage(This, page_index);
 645     if (!page) return NULL;
 646
 647     BIGBLOCKFILE_LinkHeadPage(&This->maplist, page);
 648
 649     return page;
 650 }
 651
 652 static BOOL BIGBLOCKFILE_MapPage(LPBIGBLOCKFILE This, MappedPage *page)
 653 {
 654     DWORD lowoffset = PAGE_SIZE * page->page_index;
 655
 656     if (This->fileBased)
 657     {
 658         DWORD numBytesToMap;
 659         DWORD desired_access;
 660
 661         if (lowoffset + PAGE_SIZE > This->filesize.s.LowPart)
 662             numBytesToMap = This->filesize.s.LowPart - lowoffset;
 663         else
 664             numBytesToMap = PAGE_SIZE;
 665
 666         if (This->flProtect == PAGE_READONLY)
 667             desired_access = FILE_MAP_READ;
 668         else
 669             desired_access = FILE_MAP_WRITE;
 670
 671         page->lpBytes = MapViewOfFile(This->hfilemap, desired_access, 0,
 672                                       lowoffset, numBytesToMap);
 673     }
 674     else
 675     {
 676         page->lpBytes = (LPBYTE)This->pbytearray + lowoffset;
 677     }
 678
 679     TRACE("mapped page %lu to %p\n", page->page_index, page->lpBytes);
 680
 681     return page->lpBytes != NULL;
 682 }
 683
 684 static MappedPage *BIGBLOCKFILE_CreatePage(LPBIGBLOCKFILE This,
 685                                            ULONG page_index)
 686 {
 687     MappedPage *page;
 688
 689     page = HeapAlloc(GetProcessHeap(), 0, sizeof(MappedPage));
 690     if (page == NULL)
 691       return NULL;
 692
 693     page->page_index = page_index;
 694     page->refcnt = 1;
 695
 696     page->next = NULL;
 697     page->prev = NULL;
 698
 699     BIGBLOCKFILE_MapPage(This, page);
 700
 701     BIGBLOCKFILE_Zero(&page->readable_blocks);
 702     BIGBLOCKFILE_Zero(&page->writable_blocks);
 703
 704     return page;
 705 }
 706
 707 static void BIGBLOCKFILE_UnmapPage(LPBIGBLOCKFILE This, MappedPage *page)
 708 {
 709     TRACE("%ld at %p\n", page->page_index, page->lpBytes);
 710     if (page->refcnt > 0)
 711         ERR("unmapping inuse page %p\n", page->lpBytes);
 712
 713     if (This->fileBased && page->lpBytes)
 714         UnmapViewOfFile(page->lpBytes);
 715
 716     page->lpBytes = NULL;
 717 }
 718
 719 static void BIGBLOCKFILE_DeletePage(LPBIGBLOCKFILE This, MappedPage *page)
 720 {
 721     BIGBLOCKFILE_UnmapPage(This, page);
 722
 723     HeapFree(GetProcessHeap(), 0, page);
 724 }
 725
 726 /******************************************************************************
 727  *      BIGBLOCKFILE_ReleaseMappedPage      [PRIVATE]
 728  *
 729  * Decrements the reference count of the mapped page.
 730  */
 731 static void BIGBLOCKFILE_ReleaseMappedPage(
 732   LPBIGBLOCKFILE This,
 733   MappedPage    *page)
 734 {
 735     assert(This != NULL);
 736     assert(page != NULL);
 737
 738     /* If the page is no longer refenced, move it to the victim list.
 739      * If the victim list is too long, kick somebody off. */
 740     if (!InterlockedDecrement(&page->refcnt))
 741     {
 742         if (This->maplist == page) This->maplist = page->next;
 743
 744         BIGBLOCKFILE_UnlinkPage(page);
 745
 746         if (MAX_VICTIM_PAGES > 0)
 747         {
 748             if (This->num_victim_pages >= MAX_VICTIM_PAGES)
 749             {
 750                 MappedPage *victim = This->victimtail;
 751                 if (victim)
 752                 {
 753                     This->victimtail = victim->prev;
 754                     if (This->victimhead == victim)
 755                         This->victimhead = victim->next;
 756
 757                     BIGBLOCKFILE_UnlinkPage(victim);
 758                     BIGBLOCKFILE_DeletePage(This, victim);
 759                 }
 760             }
 761             else This->num_victim_pages++;
 762
 763             BIGBLOCKFILE_LinkHeadPage(&This->victimhead, page);
 764             if (This->victimtail == NULL) This->victimtail = page;
 765         }
 766         else
 767             BIGBLOCKFILE_DeletePage(This, page);
 768     }
 769 }
 770
 771 static void BIGBLOCKFILE_DeleteList(LPBIGBLOCKFILE This, MappedPage *list)
 772 {
 773     while (list != NULL)
 774     {
 775         MappedPage *next = list->next;
 776
 777         BIGBLOCKFILE_DeletePage(This, list);
 778
 779         list = next;
 780     }
 781 }
 782
 783 /******************************************************************************
 784  *      BIGBLOCKFILE_FreeAllMappedPages     [PRIVATE]
 785  *
 786  * Unmap all currently mapped pages.
 787  * Empty mapped pages list.
 788  */
 789 static void BIGBLOCKFILE_FreeAllMappedPages(
 790   LPBIGBLOCKFILE This)
 791 {
 792     BIGBLOCKFILE_DeleteList(This, This->maplist);
 793     BIGBLOCKFILE_DeleteList(This, This->victimhead);
 794
 795     This->maplist = NULL;
 796     This->victimhead = NULL;
 797     This->victimtail = NULL;
 798     This->num_victim_pages = 0;
 799 }
 800
 801 static void BIGBLOCKFILE_UnmapList(LPBIGBLOCKFILE This, MappedPage *list)
 802 {
 803     for (; list != NULL; list = list->next)
 804     {
 805         BIGBLOCKFILE_UnmapPage(This, list);
 806     }
 807 }
 808
 809 static void BIGBLOCKFILE_UnmapAllMappedPages(LPBIGBLOCKFILE This)
 810 {
 811     BIGBLOCKFILE_UnmapList(This, This->maplist);
 812     BIGBLOCKFILE_UnmapList(This, This->victimhead);
 813 }
 814
 815 static void BIGBLOCKFILE_RemapList(LPBIGBLOCKFILE This, MappedPage *list)
 816 {
 817     while (list != NULL)
 818     {
 819         MappedPage *next = list->next;
 820
 821         if (list->page_index * PAGE_SIZE > This->filesize.s.LowPart)
 822         {
 823             TRACE("discarding %lu\n", list->page_index);
 824
 825             /* page is entirely outside of the file, delete it */
 826             BIGBLOCKFILE_UnlinkPage(list);
 827             BIGBLOCKFILE_DeletePage(This, list);
 828         }
 829         else
 830         {
 831             /* otherwise, remap it */
 832             BIGBLOCKFILE_MapPage(This, list);
 833         }
 834
 835         list = next;
 836     }
 837 }
 838
 839 static void BIGBLOCKFILE_RemapAllMappedPages(LPBIGBLOCKFILE This)
 840 {
 841     BIGBLOCKFILE_RemapList(This, This->maplist);
 842     BIGBLOCKFILE_RemapList(This, This->victimhead);
 843 }
 844
 845 /****************************************************************************
 846  *      BIGBLOCKFILE_GetProtectMode
 847  *
 848  * This function will return a protection mode flag for a file-mapping object
 849  * from the open flags of a file.
 850  */
 851 static DWORD BIGBLOCKFILE_GetProtectMode(DWORD openFlags)
 852 {
 853     if (openFlags & (STGM_WRITE | STGM_READWRITE))
 854         return PAGE_READWRITE;
 855     else
 856         return PAGE_READONLY;
 857 }