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