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