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