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 <stdarg.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include <limits.h>
  40
  41 #define COBJMACROS
  42 #define NONAMELESSUNION
  43 #define NONAMELESSSTRUCT
  44
  45 #include "windef.h"
  46 #include "winbase.h"
  47 #include "winuser.h"
  48 #include "winerror.h"
  49 #include "objbase.h"
  50 #include "ole2.h"
  51
  52 #include "storage32.h"
  53
  54 #include "wine/debug.h"
  55
  56 WINE_DEFAULT_DEBUG_CHANNEL(storage);
  57
  58 /***********************************************************
  59  * Data structures used internally by the BigBlockFile
  60  * class.
  61  */
  62
  63 /* We map in PAGE_SIZE-sized chunks. Must be a multiple of 4096. */
  64 #define PAGE_SIZE       131072
  65
  66 #define BLOCKS_PER_PAGE (PAGE_SIZE / BIG_BLOCK_SIZE)
  67
  68 /* We keep a list of recently-discarded pages. This controls the
  69  * size of that list. */
  70 #define MAX_VICTIM_PAGES 16
  71
  72 /* This structure provides one bit for each block in a page.
  73  * Use BIGBLOCKFILE_{Test,Set,Clear}Bit to manipulate it. */
  74 typedef struct
  75 {
  76     unsigned int bits[BLOCKS_PER_PAGE / (CHAR_BIT * sizeof(unsigned int))];
  77 } BlockBits;
  78
  79 /***
  80  * This structure identifies the paged that are mapped
  81  * from the file and their position in memory. It is
  82  * also used to hold a reference count to those pages.
  83  *
  84  * page_index identifies which PAGE_SIZE chunk from the
  85  * file this mapping represents. (The mappings are always
  86  * PAGE_SIZE-aligned.)
  87  */
  88 struct MappedPage
  89 {
  90     MappedPage *next;
  91     MappedPage *prev;
  92
  93     DWORD  page_index;
  94     LPVOID lpBytes;
  95     LONG   refcnt;
  96
  97     BlockBits readable_blocks;
  98     BlockBits writable_blocks;
  99 };
 100
 101 /***********************************************************
 102  * Prototypes for private methods
 103  */
 104 static void*     BIGBLOCKFILE_GetMappedView(LPBIGBLOCKFILE This,
 105                                             DWORD          page_index);
 106 static void      BIGBLOCKFILE_ReleaseMappedPage(LPBIGBLOCKFILE This,
 107                                                 MappedPage *page);
 108 static void      BIGBLOCKFILE_FreeAllMappedPages(LPBIGBLOCKFILE This);
 109 static void      BIGBLOCKFILE_UnmapAllMappedPages(LPBIGBLOCKFILE This);
 110 static void      BIGBLOCKFILE_RemapAllMappedPages(LPBIGBLOCKFILE This);
 111 static void*     BIGBLOCKFILE_GetBigBlockPointer(LPBIGBLOCKFILE This,
 112                                                  ULONG          index,
 113                                                  DWORD          desired_access);
 114 static MappedPage* BIGBLOCKFILE_GetPageFromPointer(LPBIGBLOCKFILE This,
 115                                                    void*         pBlock);
 116 static MappedPage* BIGBLOCKFILE_CreatePage(LPBIGBLOCKFILE This,
 117                                            ULONG page_index);
 118 static DWORD     BIGBLOCKFILE_GetProtectMode(DWORD openFlags);
 119 static BOOL      BIGBLOCKFILE_FileInit(LPBIGBLOCKFILE This, HANDLE hFile);
 120 static BOOL      BIGBLOCKFILE_MemInit(LPBIGBLOCKFILE This, ILockBytes* plkbyt);
 121
 122 /* Note that this evaluates a and b multiple times, so don't
 123  * pass expressions with side effects. */
 124 #define ROUND_UP(a, b) ((((a) + (b) - 1)/(b))*(b))
 125
 126 /***********************************************************
 127  * Blockbits functions.
 128  */
 129 static inline BOOL BIGBLOCKFILE_TestBit(const BlockBits *bb,
 130                                         unsigned int index)
 131 {
 132     unsigned int array_index = index / (CHAR_BIT * sizeof(unsigned int));
 133     unsigned int bit_index = index % (CHAR_BIT * sizeof(unsigned int));
 134
 135     return bb->bits[array_index] & (1 << bit_index);
 136 }
 137
 138 static inline void BIGBLOCKFILE_SetBit(BlockBits *bb, unsigned int index)
 139 {
 140     unsigned int array_index = index / (CHAR_BIT * sizeof(unsigned int));
 141     unsigned int bit_index = index % (CHAR_BIT * sizeof(unsigned int));
 142
 143     bb->bits[array_index] |= (1 << bit_index);
 144 }
 145
 146 static inline void BIGBLOCKFILE_ClearBit(BlockBits *bb, unsigned int index)
 147 {
 148     unsigned int array_index = index / (CHAR_BIT * sizeof(unsigned int));
 149     unsigned int bit_index = index % (CHAR_BIT * sizeof(unsigned int));
 150
 151     bb->bits[array_index] &= ~(1 << bit_index);
 152 }
 153
 154 static inline void BIGBLOCKFILE_Zero(BlockBits *bb)
 155 {
 156     memset(bb->bits, 0, sizeof(bb->bits));
 157 }
 158
 159 /******************************************************************************
 160  *      BIGBLOCKFILE_Construct
 161  *
 162  * Construct a big block file. Create the file mapping object.
 163  * Create the read only mapped pages list, the writable mapped page list
 164  * and the blocks in use list.
 165  */
 166 BigBlockFile * BIGBLOCKFILE_Construct(
 167   HANDLE   hFile,
 168   ILockBytes* pLkByt,
 169   DWORD    openFlags,
 170   ULONG    blocksize,
 171   BOOL     fileBased)
 172 {
 173   LPBIGBLOCKFILE This;
 174
 175   This = (LPBIGBLOCKFILE)HeapAlloc(GetProcessHeap(), 0, sizeof(BigBlockFile));
 176
 177   if (This == NULL)
 178     return NULL;
 179
 180   This->fileBased = fileBased;
 181
 182   This->flProtect = BIGBLOCKFILE_GetProtectMode(openFlags);
 183
 184   This->blocksize = blocksize;
 185
 186   This->maplist = NULL;
 187   This->victimhead = NULL;
 188   This->victimtail = NULL;
 189   This->num_victim_pages = 0;
 190
 191   if (This->fileBased)
 192   {
 193     if (!BIGBLOCKFILE_FileInit(This, hFile))
 194     {
 195       HeapFree(GetProcessHeap(), 0, This);
 196       return NULL;
 197     }
 198   }
 199   else
 200   {
 201     if (!BIGBLOCKFILE_MemInit(This, pLkByt))
 202     {
 203       HeapFree(GetProcessHeap(), 0, This);
 204       return NULL;
 205     }
 206   }
 207
 208   return This;
 209 }
 210
 211 /******************************************************************************
 212  *      BIGBLOCKFILE_FileInit
 213  *
 214  * Initialize a big block object supported by a file.
 215  */
 216 static BOOL BIGBLOCKFILE_FileInit(LPBIGBLOCKFILE This, HANDLE hFile)
 217 {
 218   This->pLkbyt     = NULL;
 219   This->hbytearray = 0;
 220   This->pbytearray = NULL;
 221
 222   This->hfile = hFile;
 223
 224   if (This->hfile == INVALID_HANDLE_VALUE)
 225     return FALSE;
 226
 227   This->filesize.u.LowPart = GetFileSize(This->hfile,
 228                                          &This->filesize.u.HighPart);
 229
 230   if( This->filesize.u.LowPart || This->filesize.u.HighPart )
 231   {
 232     /* create the file mapping object
 233      */
 234     This->hfilemap = CreateFileMappingA(This->hfile,
 235                                         NULL,
 236                                         This->flProtect,
 237                                         0, 0,
 238                                         NULL);
 239
 240     if (!This->hfilemap)
 241     {
 242       CloseHandle(This->hfile);
 243       return FALSE;
 244     }
 245   }
 246   else
 247     This->hfilemap = NULL;
 248
 249   This->maplist = NULL;
 250
 251   TRACE("file len %lu\n", This->filesize.u.LowPart);
 252
 253   return TRUE;
 254 }
 255
 256 /******************************************************************************
 257  *      BIGBLOCKFILE_MemInit
 258  *
 259  * Initialize a big block object supported by an ILockBytes on HGLOABL.
 260  */
 261 static BOOL BIGBLOCKFILE_MemInit(LPBIGBLOCKFILE This, ILockBytes* plkbyt)
 262 {
 263   This->hfile       = 0;
 264   This->hfilemap    = 0;
 265
 266   /*
 267    * Retrieve the handle to the byte array from the LockByte object.
 268    */
 269   if (GetHGlobalFromILockBytes(plkbyt, &(This->hbytearray)) != S_OK)
 270   {
 271     FIXME("May not be an ILockBytes on HGLOBAL\n");
 272     return FALSE;
 273   }
 274
 275   This->pLkbyt = plkbyt;
 276
 277   /*
 278    * Increment the reference count of the ILockByte object since
 279    * we're keeping a reference to it.
 280    */
 281   ILockBytes_AddRef(This->pLkbyt);
 282
 283   This->filesize.u.LowPart = GlobalSize(This->hbytearray);
 284   This->filesize.u.HighPart = 0;
 285
 286   This->pbytearray = GlobalLock(This->hbytearray);
 287
 288   TRACE("mem on %p len %lu\n", This->pbytearray, This->filesize.u.LowPart);
 289
 290   return TRUE;
 291 }
 292
 293 /******************************************************************************
 294  *      BIGBLOCKFILE_Destructor
 295  *
 296  * Destructor. Clean up, free memory.
 297  */
 298 void BIGBLOCKFILE_Destructor(
 299   LPBIGBLOCKFILE This)
 300 {
 301   BIGBLOCKFILE_FreeAllMappedPages(This);
 302
 303   if (This->fileBased)
 304   {
 305     CloseHandle(This->hfilemap);
 306     CloseHandle(This->hfile);
 307   }
 308   else
 309   {
 310     GlobalUnlock(This->hbytearray);
 311     ILockBytes_Release(This->pLkbyt);
 312   }
 313
 314   /* destroy this
 315    */
 316   HeapFree(GetProcessHeap(), 0, This);
 317 }
 318
 319 /******************************************************************************
 320  *      BIGBLOCKFILE_GetROBigBlock
 321  *
 322  * Returns the specified block in read only mode.
 323  * Will return NULL if the block doesn't exists.
 324  */
 325 void* BIGBLOCKFILE_GetROBigBlock(
 326   LPBIGBLOCKFILE This,
 327   ULONG          index)
 328 {
 329   /*
 330    * block index starts at -1
 331    * translate to zero based index
 332    */
 333   if (index == 0xffffffff)
 334     index = 0;
 335   else
 336     index++;
 337
 338   /*
 339    * validate the block index
 340    *
 341    */
 342   if (This->blocksize * (index + 1)
 343       > ROUND_UP(This->filesize.u.LowPart, This->blocksize))
 344   {
 345     TRACE("out of range %lu vs %lu\n", This->blocksize * (index + 1),
 346           This->filesize.u.LowPart);
 347     return NULL;
 348   }
 349
 350   return BIGBLOCKFILE_GetBigBlockPointer(This, index, FILE_MAP_READ);
 351 }
 352
 353 /******************************************************************************
 354  *      BIGBLOCKFILE_GetBigBlock
 355  *
 356  * Returns the specified block.
 357  * Will grow the file if necessary.
 358  */
 359 void* BIGBLOCKFILE_GetBigBlock(LPBIGBLOCKFILE This, ULONG index)
 360 {
 361   /*
 362    * block index starts at -1
 363    * translate to zero based index
 364    */
 365   if (index == 0xffffffff)
 366     index = 0;
 367   else
 368     index++;
 369
 370   /*
 371    * make sure that the block physically exists
 372    */
 373   if ((This->blocksize * (index + 1)) > This->filesize.u.LowPart)
 374   {
 375     ULARGE_INTEGER newSize;
 376
 377     newSize.u.HighPart = 0;
 378     newSize.u.LowPart = This->blocksize * (index + 1);
 379
 380     BIGBLOCKFILE_SetSize(This, newSize);
 381   }
 382
 383   return BIGBLOCKFILE_GetBigBlockPointer(This, index, FILE_MAP_WRITE);
 384 }
 385
 386 /******************************************************************************
 387  *      BIGBLOCKFILE_ReleaseBigBlock
 388  *
 389  * Releases the specified block.
 390  */
 391 void BIGBLOCKFILE_ReleaseBigBlock(LPBIGBLOCKFILE This, void *pBlock)
 392 {
 393     MappedPage *page;
 394
 395     if (pBlock == NULL)
 396         return;
 397
 398     page = BIGBLOCKFILE_GetPageFromPointer(This, pBlock);
 399
 400     if (page == NULL)
 401         return;
 402
 403     BIGBLOCKFILE_ReleaseMappedPage(This, page);
 404 }
 405
 406 /******************************************************************************
 407  *      BIGBLOCKFILE_SetSize
 408  *
 409  * Sets the size of the file.
 410  *
 411  */
 412 void BIGBLOCKFILE_SetSize(LPBIGBLOCKFILE This, ULARGE_INTEGER newSize)
 413 {
 414   if (This->filesize.u.LowPart == newSize.u.LowPart)
 415     return;
 416
 417   TRACE("from %lu to %lu\n", This->filesize.u.LowPart, newSize.u.LowPart);
 418   /*
 419    * unmap all views, must be done before call to SetEndFile
 420    */
 421   BIGBLOCKFILE_UnmapAllMappedPages(This);
 422
 423   if (This->fileBased)
 424   {
 425     char buf[10];
 426
 427     /*
 428      * close file-mapping object, must be done before call to SetEndFile
 429      */
 430     if( This->hfilemap )
 431       CloseHandle(This->hfilemap);
 432     This->hfilemap = 0;
 433
 434     /*
 435      * BEGIN HACK
 436      * This fixes a bug when saving through smbfs.
 437      * smbmount a Windows shared directory, save a structured storage file
 438      * to that dir: crash.
 439      *
 440      * The problem is that the SetFilePointer-SetEndOfFile combo below
 441      * doesn't always succeed. The file is not grown. It seems like the
 442      * operation is cached. By doing the WriteFile, the file is actually
 443      * grown on disk.
 444      * This hack is only needed when saving to smbfs.
 445      */
 446     memset(buf, '0', 10);
 447     SetFilePointer(This->hfile, newSize.u.LowPart, NULL, FILE_BEGIN);
 448     WriteFile(This->hfile, buf, 10, NULL, NULL);
 449     /*
 450      * END HACK
 451      */
 452
 453     /*
 454      * set the new end of file
 455      */
 456     SetFilePointer(This->hfile, newSize.u.LowPart, NULL, FILE_BEGIN);
 457     SetEndOfFile(This->hfile);
 458
 459     /*
 460      * re-create the file mapping object
 461      */
 462     This->hfilemap = CreateFileMappingA(This->hfile,
 463                                         NULL,
 464                                         This->flProtect,
 465                                         0, 0,
 466                                         NULL);
 467   }
 468   else
 469   {
 470     GlobalUnlock(This->hbytearray);
 471
 472     /*
 473      * Resize the byte array object.
 474      */
 475     ILockBytes_SetSize(This->pLkbyt, newSize);
 476
 477     /*
 478      * Re-acquire the handle, it may have changed.
 479      */
 480     GetHGlobalFromILockBytes(This->pLkbyt, &This->hbytearray);
 481     This->pbytearray = GlobalLock(This->hbytearray);
 482   }
 483
 484   This->filesize.u.LowPart = newSize.u.LowPart;
 485   This->filesize.u.HighPart = newSize.u.HighPart;
 486
 487   BIGBLOCKFILE_RemapAllMappedPages(This);
 488 }
 489
 490 /******************************************************************************
 491  *      BIGBLOCKFILE_GetSize
 492  *
 493  * Returns the size of the file.
 494  *
 495  */
 496 ULARGE_INTEGER BIGBLOCKFILE_GetSize(LPBIGBLOCKFILE This)
 497 {
 498   return This->filesize;
 499 }
 500
 501 /******************************************************************************
 502  *      BIGBLOCKFILE_AccessCheck     [PRIVATE]
 503  *
 504  * block_index is the index within the page.
 505  */
 506 static BOOL BIGBLOCKFILE_AccessCheck(MappedPage *page, ULONG block_index,
 507                                      DWORD desired_access)
 508 {
 509     assert(block_index < BLOCKS_PER_PAGE);
 510
 511     if (desired_access == FILE_MAP_READ)
 512     {
 513         if (BIGBLOCKFILE_TestBit(&page->writable_blocks, block_index))
 514             return FALSE;
 515
 516         BIGBLOCKFILE_SetBit(&page->readable_blocks, block_index);
 517     }
 518     else
 519     {
 520         assert(desired_access == FILE_MAP_WRITE);
 521
 522         if (BIGBLOCKFILE_TestBit(&page->readable_blocks, block_index))
 523             return FALSE;
 524
 525         BIGBLOCKFILE_SetBit(&page->writable_blocks, block_index);
 526     }
 527
 528     return TRUE;
 529 }
 530
 531 /******************************************************************************
 532  *      BIGBLOCKFILE_GetBigBlockPointer     [PRIVATE]
 533  *
 534  * Returns a pointer to the specified block.
 535  */
 536 static void* BIGBLOCKFILE_GetBigBlockPointer(
 537   LPBIGBLOCKFILE This,
 538   ULONG          block_index,
 539   DWORD          desired_access)
 540 {
 541     DWORD page_index = block_index / BLOCKS_PER_PAGE;
 542     DWORD block_on_page = block_index % BLOCKS_PER_PAGE;
 543
 544     MappedPage *page = BIGBLOCKFILE_GetMappedView(This, page_index);
 545     if (!page || !page->lpBytes) return NULL;
 546
 547     if (!BIGBLOCKFILE_AccessCheck(page, block_on_page, desired_access))
 548     {
 549         BIGBLOCKFILE_ReleaseMappedPage(This, page);
 550         return NULL;
 551     }
 552
 553     return (LPBYTE)page->lpBytes + (block_on_page * This->blocksize);
 554 }
 555
 556 /******************************************************************************
 557  *      BIGBLOCKFILE_GetMappedPageFromPointer     [PRIVATE]
 558  *
 559  * pBlock is a pointer to a block on a page.
 560  * The page has to be on the in-use list. (As oppsed to the victim list.)
 561  *
 562  * Does not increment the usage count.
 563  */
 564 static MappedPage *BIGBLOCKFILE_GetPageFromPointer(LPBIGBLOCKFILE This,
 565                                                    void *pBlock)
 566 {
 567     MappedPage *page;
 568
 569     for (page = This->maplist; page != NULL; page = page->next)
 570     {
 571         if ((LPBYTE)pBlock >= (LPBYTE)page->lpBytes
 572             && (LPBYTE)pBlock <= (LPBYTE)page->lpBytes + PAGE_SIZE)
 573             break;
 574
 575     }
 576
 577     return page;
 578 }
 579
 580 /******************************************************************************
 581  *      BIGBLOCKFILE_FindPageInList      [PRIVATE]
 582  *
 583  */
 584 static MappedPage *BIGBLOCKFILE_FindPageInList(MappedPage *head,
 585                                                ULONG page_index)
 586 {
 587     for (; head != NULL; head = head->next)
 588     {
 589         if (head->page_index == page_index)
 590         {
 591             InterlockedIncrement(&head->refcnt);
 592             break;
 593         }
 594     }
 595
 596     return head;
 597
 598 }
 599
 600 static void BIGBLOCKFILE_UnlinkPage(MappedPage *page)
 601 {
 602     if (page->next) page->next->prev = page->prev;
 603     if (page->prev) page->prev->next = page->next;
 604 }
 605
 606 static void BIGBLOCKFILE_LinkHeadPage(MappedPage **head, MappedPage *page)
 607 {
 608     if (*head) (*head)->prev = page;
 609     page->next = *head;
 610     page->prev = NULL;
 611     *head = page;
 612 }
 613
 614 /******************************************************************************
 615  *      BIGBLOCKFILE_GetMappedView      [PRIVATE]
 616  *
 617  * Gets the page requested if it is already mapped.
 618  * If it's not already mapped, this method will map it
 619  */
 620 static void * BIGBLOCKFILE_GetMappedView(
 621   LPBIGBLOCKFILE This,
 622   DWORD          page_index)
 623 {
 624     MappedPage *page;
 625
 626     page = BIGBLOCKFILE_FindPageInList(This->maplist, page_index);
 627     if (!page)
 628     {
 629         page = BIGBLOCKFILE_FindPageInList(This->victimhead, page_index);
 630         if (page)
 631         {
 632             This->num_victim_pages--;
 633
 634             BIGBLOCKFILE_Zero(&page->readable_blocks);
 635             BIGBLOCKFILE_Zero(&page->writable_blocks);
 636         }
 637     }
 638
 639     if (page)
 640     {
 641         /* If the page is not already at the head of the list, move
 642          * it there. (Also moves pages from victim to main list.) */
 643         if (This->maplist != page)
 644         {
 645             if (This->victimhead == page) This->victimhead = page->next;
 646             if (This->victimtail == page) This->victimtail = page->prev;
 647
 648             BIGBLOCKFILE_UnlinkPage(page);
 649
 650             BIGBLOCKFILE_LinkHeadPage(&This->maplist, page);
 651         }
 652
 653         return page;
 654     }
 655
 656     page = BIGBLOCKFILE_CreatePage(This, page_index);
 657     if (!page) return NULL;
 658
 659     BIGBLOCKFILE_LinkHeadPage(&This->maplist, page);
 660
 661     return page;
 662 }
 663
 664 static BOOL BIGBLOCKFILE_MapPage(LPBIGBLOCKFILE This, MappedPage *page)
 665 {
 666     DWORD lowoffset = PAGE_SIZE * page->page_index;
 667
 668     if (This->fileBased)
 669     {
 670         DWORD numBytesToMap;
 671         DWORD desired_access;
 672
 673         if( !This->hfilemap )
 674             return FALSE;
 675
 676         if (lowoffset + PAGE_SIZE > This->filesize.u.LowPart)
 677             numBytesToMap = This->filesize.u.LowPart - lowoffset;
 678         else
 679             numBytesToMap = PAGE_SIZE;
 680
 681         if (This->flProtect == PAGE_READONLY)
 682             desired_access = FILE_MAP_READ;
 683         else
 684             desired_access = FILE_MAP_WRITE;
 685
 686         page->lpBytes = MapViewOfFile(This->hfilemap, desired_access, 0,
 687                                       lowoffset, numBytesToMap);
 688     }
 689     else
 690     {
 691         page->lpBytes = (LPBYTE)This->pbytearray + lowoffset;
 692     }
 693
 694     TRACE("mapped page %lu to %p\n", page->page_index, page->lpBytes);
 695
 696     return page->lpBytes != NULL;
 697 }
 698
 699 static MappedPage *BIGBLOCKFILE_CreatePage(LPBIGBLOCKFILE This,
 700                                            ULONG page_index)
 701 {
 702     MappedPage *page;
 703
 704     page = HeapAlloc(GetProcessHeap(), 0, sizeof(MappedPage));
 705     if (page == NULL)
 706       return NULL;
 707
 708     page->page_index = page_index;
 709     page->refcnt = 1;
 710
 711     page->next = NULL;
 712     page->prev = NULL;
 713
 714     BIGBLOCKFILE_MapPage(This, page);
 715
 716     BIGBLOCKFILE_Zero(&page->readable_blocks);
 717     BIGBLOCKFILE_Zero(&page->writable_blocks);
 718
 719     return page;
 720 }
 721
 722 static void BIGBLOCKFILE_UnmapPage(LPBIGBLOCKFILE This, MappedPage *page)
 723 {
 724     TRACE("%ld at %p\n", page->page_index, page->lpBytes);
 725     if (page->refcnt > 0)
 726         ERR("unmapping inuse page %p\n", page->lpBytes);
 727
 728     if (This->fileBased && page->lpBytes)
 729         UnmapViewOfFile(page->lpBytes);
 730
 731     page->lpBytes = NULL;
 732 }
 733
 734 static void BIGBLOCKFILE_DeletePage(LPBIGBLOCKFILE This, MappedPage *page)
 735 {
 736     BIGBLOCKFILE_UnmapPage(This, page);
 737
 738     HeapFree(GetProcessHeap(), 0, page);
 739 }
 740
 741 /******************************************************************************
 742  *      BIGBLOCKFILE_ReleaseMappedPage      [PRIVATE]
 743  *
 744  * Decrements the reference count of the mapped page.
 745  */
 746 static void BIGBLOCKFILE_ReleaseMappedPage(
 747   LPBIGBLOCKFILE This,
 748   MappedPage    *page)
 749 {
 750     assert(This != NULL);
 751     assert(page != NULL);
 752
 753     /* If the page is no longer refenced, move it to the victim list.
 754      * If the victim list is too long, kick somebody off. */
 755     if (!InterlockedDecrement(&page->refcnt))
 756     {
 757         if (This->maplist == page) This->maplist = page->next;
 758
 759         BIGBLOCKFILE_UnlinkPage(page);
 760
 761         if (MAX_VICTIM_PAGES > 0)
 762         {
 763             if (This->num_victim_pages >= MAX_VICTIM_PAGES)
 764             {
 765                 MappedPage *victim = This->victimtail;
 766                 if (victim)
 767                 {
 768                     This->victimtail = victim->prev;
 769                     if (This->victimhead == victim)
 770                         This->victimhead = victim->next;
 771
 772                     BIGBLOCKFILE_UnlinkPage(victim);
 773                     BIGBLOCKFILE_DeletePage(This, victim);
 774                 }
 775             }
 776             else This->num_victim_pages++;
 777
 778             BIGBLOCKFILE_LinkHeadPage(&This->victimhead, page);
 779             if (This->victimtail == NULL) This->victimtail = page;
 780         }
 781         else
 782             BIGBLOCKFILE_DeletePage(This, page);
 783     }
 784 }
 785
 786 static void BIGBLOCKFILE_DeleteList(LPBIGBLOCKFILE This, MappedPage *list)
 787 {
 788     while (list != NULL)
 789     {
 790         MappedPage *next = list->next;
 791
 792         BIGBLOCKFILE_DeletePage(This, list);
 793
 794         list = next;
 795     }
 796 }
 797
 798 /******************************************************************************
 799  *      BIGBLOCKFILE_FreeAllMappedPages     [PRIVATE]
 800  *
 801  * Unmap all currently mapped pages.
 802  * Empty mapped pages list.
 803  */
 804 static void BIGBLOCKFILE_FreeAllMappedPages(
 805   LPBIGBLOCKFILE This)
 806 {
 807     BIGBLOCKFILE_DeleteList(This, This->maplist);
 808     BIGBLOCKFILE_DeleteList(This, This->victimhead);
 809
 810     This->maplist = NULL;
 811     This->victimhead = NULL;
 812     This->victimtail = NULL;
 813     This->num_victim_pages = 0;
 814 }
 815
 816 static void BIGBLOCKFILE_UnmapList(LPBIGBLOCKFILE This, MappedPage *list)
 817 {
 818     for (; list != NULL; list = list->next)
 819     {
 820         BIGBLOCKFILE_UnmapPage(This, list);
 821     }
 822 }
 823
 824 static void BIGBLOCKFILE_UnmapAllMappedPages(LPBIGBLOCKFILE This)
 825 {
 826     BIGBLOCKFILE_UnmapList(This, This->maplist);
 827     BIGBLOCKFILE_UnmapList(This, This->victimhead);
 828 }
 829
 830 static void BIGBLOCKFILE_RemapList(LPBIGBLOCKFILE This, MappedPage *list)
 831 {
 832     while (list != NULL)
 833     {
 834         MappedPage *next = list->next;
 835
 836         if (list->page_index * PAGE_SIZE > This->filesize.u.LowPart)
 837         {
 838             TRACE("discarding %lu\n", list->page_index);
 839
 840             /* page is entirely outside of the file, delete it */
 841             BIGBLOCKFILE_UnlinkPage(list);
 842             BIGBLOCKFILE_DeletePage(This, list);
 843         }
 844         else
 845         {
 846             /* otherwise, remap it */
 847             BIGBLOCKFILE_MapPage(This, list);
 848         }
 849
 850         list = next;
 851     }
 852 }
 853
 854 static void BIGBLOCKFILE_RemapAllMappedPages(LPBIGBLOCKFILE This)
 855 {
 856     BIGBLOCKFILE_RemapList(This, This->maplist);
 857     BIGBLOCKFILE_RemapList(This, This->victimhead);
 858 }
 859
 860 /****************************************************************************
 861  *      BIGBLOCKFILE_GetProtectMode
 862  *
 863  * This function will return a protection mode flag for a file-mapping object
 864  * from the open flags of a file.
 865  */
 866 static DWORD BIGBLOCKFILE_GetProtectMode(DWORD openFlags)
 867 {
 868     if (openFlags & (STGM_WRITE | STGM_READWRITE))
 869         return PAGE_READWRITE;
 870     else
 871         return PAGE_READONLY;
 872 }