store/source/storbase.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_STORE_SOURCE_STORBASE_HXX
  21 #define INCLUDED_STORE_SOURCE_STORBASE_HXX
  22
  23 #include "sal/config.h"
  24 #include "salhelper/simplereferenceobject.hxx"
  25
  26 #include "sal/types.h"
  27
  28 #include "rtl/alloc.h"
  29 #include "rtl/crc.h"
  30 #include "rtl/ref.hxx"
  31
  32 #include "osl/diagnose.h"
  33 #include "osl/endian.h"
  34
  35 #include "store/types.h"
  36
  37 #include <stddef.h>
  38 #include <string.h>
  39
  40 /*========================================================================
  41  *
  42  * store common internals.
  43  *
  44  *======================================================================*/
  45
  46 #ifndef STORE_IMPL_ISP2
  47 #define STORE_IMPL_ISP2(value) (((value) & ((value) - 1)) == 0)
  48 #endif
  49
  50 #ifndef STORE_IMPL_CONCAT
  51 #define STORE_IMPL_CONCAT(x, y) STORE_IMPL_CONCAT2(x,y)
  52 #define STORE_IMPL_CONCAT2(x, y) x##y
  53 #endif
  54
  55 namespace store
  56 {
  57
  58 #ifdef htons
  59 #undef htons
  60 #endif
  61 #ifdef ntohs
  62 #undef ntohs
  63 #endif
  64
  65 #ifdef htonl
  66 #undef htonl
  67 #endif
  68 #ifdef ntohl
  69 #undef ntohl
  70 #endif
  71
  72 #ifdef OSL_BIGENDIAN
  73 inline sal_uInt16 htons (sal_uInt16 h) { return OSL_SWAPWORD(h); }
  74 inline sal_uInt16 ntohs (sal_uInt16 n) { return OSL_SWAPWORD(n); }
  75
  76 inline sal_uInt32 htonl (sal_uInt32 h) { return OSL_SWAPDWORD(h); }
  77 inline sal_uInt32 ntohl (sal_uInt32 n) { return OSL_SWAPDWORD(n); }
  78 #else
  79 inline sal_uInt16 htons (sal_uInt16 h) { return h; }
  80 inline sal_uInt16 ntohs (sal_uInt16 n) { return n; }
  81
  82 inline sal_uInt32 htonl (sal_uInt32 h) { return h; }
  83 inline sal_uInt32 ntohl (sal_uInt32 n) { return n; }
  84 #endif /* OSL_BIGENDIAN */
  85
  86 /** swap.
  87  */
  88 template< typename T > void swap (T & lhs, T & rhs)
  89 {
  90     T tmp = lhs; lhs = rhs; rhs = tmp;
  91 }
  92
  93 /*========================================================================
  94  *
  95  * SharedCount.
  96  *
  97  *======================================================================*/
  98 class SharedCount
  99 {
 100     long * m_pCount;
 101
 102     class Allocator
 103     {
 104         rtl_cache_type * m_cache;
 105
 106     public:
 107         static Allocator & get();
 108
 109         long * alloc()
 110         {
 111             return static_cast<long*>(rtl_cache_alloc (m_cache));
 112         }
 113         void free (long * pCount)
 114         {
 115             rtl_cache_free (m_cache, pCount);
 116         }
 117
 118     protected:
 119         Allocator();
 120         ~Allocator();
 121     };
 122
 123 public:
 124     SharedCount()
 125         : m_pCount(Allocator::get().alloc())
 126     {
 127         if (m_pCount != 0) (*m_pCount) = 1;
 128     }
 129
 130     ~SharedCount()
 131     {
 132         if (m_pCount != 0)
 133         {
 134             long new_count = --(*m_pCount);
 135             if (new_count == 0)
 136                 Allocator::get().free(m_pCount);
 137         }
 138     }
 139
 140     void swap (SharedCount & rhs) // nothrow
 141     {
 142         store::swap(m_pCount, rhs.m_pCount);
 143     }
 144
 145     SharedCount (SharedCount const & rhs) // nothrow
 146         : m_pCount (rhs.m_pCount)
 147     {
 148         if (m_pCount != 0) ++(*m_pCount);
 149     }
 150     SharedCount & operator= (SharedCount const & rhs) // nothrow
 151     {
 152         SharedCount tmp(rhs);
 153         swap(tmp);
 154         return *this;
 155     }
 156
 157     bool operator== (long count) const
 158     {
 159         return (m_pCount != 0) && (*m_pCount == count);
 160     }
 161 };
 162
 163 /*========================================================================
 164  *
 165  * OStorePageGuard.
 166  *
 167  *======================================================================*/
 168 struct OStorePageGuard
 169 {
 170     /** Representation.
 171      */
 172     sal_uInt32 m_nMagic;
 173     sal_uInt32 m_nCRC32;
 174
 175     /** Construction.
 176      */
 177     explicit OStorePageGuard (sal_uInt32 nMagic = 0, sal_uInt32 nCRC32 = 0)
 178         : m_nMagic (store::htonl(nMagic)),
 179           m_nCRC32 (store::htonl(nCRC32))
 180     {}
 181
 182     void swap (OStorePageGuard & rhs)
 183     {
 184         store::swap(m_nMagic, rhs.m_nMagic);
 185         store::swap(m_nCRC32, rhs.m_nCRC32);
 186     }
 187
 188     OStorePageGuard (OStorePageGuard const & rhs)
 189         : m_nMagic (rhs.m_nMagic),
 190           m_nCRC32 (rhs.m_nCRC32)
 191     {}
 192
 193     OStorePageGuard& operator= (const OStorePageGuard& rhs)
 194     {
 195         m_nMagic = rhs.m_nMagic;
 196         m_nCRC32 = rhs.m_nCRC32;
 197         return *this;
 198     }
 199
 200     /** Comparison.
 201      */
 202     bool operator== (const OStorePageGuard& rhs) const
 203     {
 204         return ((m_nMagic == rhs.m_nMagic) &&
 205                 (m_nCRC32 == rhs.m_nCRC32)    );
 206     }
 207 };
 208
 209 /*========================================================================
 210  *
 211  * OStorePageDescriptor.
 212  *
 213  *======================================================================*/
 214 #define STORE_PAGE_NULL ((sal_uInt32)(~0))
 215
 216 struct OStorePageDescriptor
 217 {
 218     /** Representation.
 219      */
 220     sal_uInt32 m_nAddr;
 221     sal_uInt16 m_nSize;
 222     sal_uInt16 m_nUsed;
 223
 224     /** Construction.
 225      */
 226     explicit OStorePageDescriptor (
 227         sal_uInt32 nAddr = STORE_PAGE_NULL,
 228         sal_uInt16 nSize = 0,
 229         sal_uInt16 nUsed = 0)
 230         : m_nAddr (store::htonl(nAddr)),
 231           m_nSize (store::htons(nSize)),
 232           m_nUsed (store::htons(nUsed))
 233     {}
 234
 235     void swap (OStorePageDescriptor & rhs)
 236     {
 237         store::swap(m_nAddr, rhs.m_nAddr);
 238         store::swap(m_nSize, rhs.m_nSize);
 239         store::swap(m_nUsed, rhs.m_nUsed);
 240     }
 241
 242     OStorePageDescriptor (const OStorePageDescriptor & rhs)
 243         : m_nAddr (rhs.m_nAddr),
 244           m_nSize (rhs.m_nSize),
 245           m_nUsed (rhs.m_nUsed)
 246     {}
 247
 248     OStorePageDescriptor & operator= (const OStorePageDescriptor & rhs)
 249     {
 250         m_nAddr = rhs.m_nAddr;
 251         m_nSize = rhs.m_nSize;
 252         m_nUsed = rhs.m_nUsed;
 253         return *this;
 254     }
 255
 256     /** Comparison.
 257      */
 258     bool operator== (const OStorePageDescriptor & rhs) const
 259     {
 260         return ((m_nAddr == rhs.m_nAddr) &&
 261                 (m_nSize == rhs.m_nSize)    );
 262     }
 263
 264     bool operator<= (const OStorePageDescriptor & rhs) const
 265     {
 266         return ((m_nAddr               == rhs.m_nAddr              ) &&
 267                 (store::ntohs(m_nSize) <= store::ntohs(rhs.m_nSize))    );
 268     }
 269
 270     bool operator< (const OStorePageDescriptor & rhs) const
 271     {
 272         if (m_nAddr == rhs.m_nAddr)
 273             return (store::ntohs(m_nSize) < store::ntohs(rhs.m_nSize));
 274         else
 275             return (store::ntohl(m_nAddr) < store::ntohl(rhs.m_nAddr));
 276     }
 277 };
 278
 279 /*========================================================================
 280  *
 281  * OStorePageKey.
 282  *
 283  *======================================================================*/
 284 struct OStorePageKey
 285 {
 286     /** Representation.
 287      */
 288     sal_uInt32 m_nLow;
 289     sal_uInt32 m_nHigh;
 290
 291     /** Construction.
 292      */
 293     explicit OStorePageKey (sal_uInt32 nLow = 0, sal_uInt32 nHigh = 0)
 294         : m_nLow  (store::htonl(nLow)),
 295           m_nHigh (store::htonl(nHigh))
 296     {}
 297
 298     void swap (OStorePageKey & rhs)
 299     {
 300         store::swap(m_nLow,  rhs.m_nLow);
 301         store::swap(m_nHigh, rhs.m_nHigh);
 302     }
 303
 304     OStorePageKey (const OStorePageKey & rhs)
 305         : m_nLow (rhs.m_nLow), m_nHigh (rhs.m_nHigh)
 306     {}
 307
 308     OStorePageKey & operator= (const OStorePageKey & rhs)
 309     {
 310         m_nLow  = rhs.m_nLow;
 311         m_nHigh = rhs.m_nHigh;
 312         return *this;
 313     }
 314
 315     /** Comparison.
 316      */
 317     bool operator== (const OStorePageKey & rhs) const
 318     {
 319         return ((m_nLow  == rhs.m_nLow ) &&
 320                 (m_nHigh == rhs.m_nHigh)    );
 321     }
 322
 323     bool operator< (const OStorePageKey & rhs) const
 324     {
 325         if (m_nHigh == rhs.m_nHigh)
 326             return (store::ntohl(m_nLow) < store::ntohl(rhs.m_nLow));
 327         else
 328             return (store::ntohl(m_nHigh) < store::ntohl(rhs.m_nHigh));
 329     }
 330 };
 331
 332 /*========================================================================
 333  *
 334  * OStorePageLink.
 335  *
 336  *======================================================================*/
 337 struct OStorePageLink
 338 {
 339     /** Representation.
 340      */
 341     sal_uInt32 m_nAddr;
 342
 343     /** Construction.
 344      */
 345     explicit OStorePageLink (sal_uInt32 nAddr = STORE_PAGE_NULL)
 346         : m_nAddr (store::htonl(nAddr))
 347     {}
 348
 349     void swap (OStorePageLink & rhs)
 350     {
 351         store::swap(m_nAddr, rhs.m_nAddr);
 352     }
 353
 354     OStorePageLink (const OStorePageLink & rhs)
 355         : m_nAddr (rhs.m_nAddr)
 356     {}
 357
 358     OStorePageLink & operator= (const OStorePageLink & rhs)
 359     {
 360         m_nAddr = rhs.m_nAddr;
 361         return *this;
 362     }
 363
 364     OStorePageLink & operator= (sal_uInt32 nAddr)
 365     {
 366         m_nAddr = store::htonl(nAddr);
 367         return *this;
 368     }
 369
 370     /** Comparison.
 371      */
 372     bool operator== (const OStorePageLink & rhs) const
 373     {
 374         return (m_nAddr == rhs.m_nAddr);
 375     }
 376
 377     bool operator< (const OStorePageLink& rhs) const
 378     {
 379         return (store::ntohl(m_nAddr) < store::ntohl(rhs.m_nAddr));
 380     }
 381
 382     /** Operation.
 383      */
 384     sal_uInt32 location() const
 385     {
 386         return store::ntohl(m_nAddr);
 387     }
 388
 389     void link (OStorePageLink & rPred)
 390     {
 391         // @@@ swap (rPred); @@@
 392         OStorePageLink tmp (rPred);
 393         rPred = *this;
 394         *this = tmp;
 395     }
 396
 397     void unlink (OStorePageLink& rPred)
 398     {
 399         rPred = *this;
 400         *this = OStorePageLink();
 401     }
 402 };
 403
 404 /*========================================================================
 405  *
 406  * PageData.
 407  *
 408  *======================================================================*/
 409 typedef struct PageData OStorePageData; // backward compat.
 410 struct PageData
 411 {
 412     typedef OStorePageGuard      G;
 413     typedef OStorePageDescriptor D;
 414     typedef OStorePageLink       L;
 415
 416     /** Representation.
 417      */
 418     G m_aGuard;
 419     D m_aDescr;
 420     L m_aMarked;
 421     L m_aUnused;
 422
 423     /** theSize.
 424      */
 425     static const size_t     theSize     = sizeof(G) + sizeof(D) + 2 * sizeof(L);
 426     static const sal_uInt16 thePageSize = theSize;
 427     static_assert(STORE_MINIMUM_PAGESIZE >= thePageSize, "must be at least thePageSize");
 428
 429     /** location.
 430      */
 431     sal_uInt32 location() const
 432     {
 433         return store::ntohl(m_aDescr.m_nAddr);
 434     }
 435     void location (sal_uInt32 nAddr)
 436     {
 437         m_aDescr.m_nAddr = store::htonl(nAddr);
 438     }
 439
 440     /** size.
 441      */
 442     sal_uInt16 size() const
 443     {
 444         return store::ntohs(m_aDescr.m_nSize);
 445     }
 446
 447     /** type.
 448      */
 449     sal_uInt32 type() const
 450     {
 451         return store::ntohl(m_aGuard.m_nMagic);
 452     }
 453
 454     /** Allocation.
 455      */
 456     class Allocator_Impl;
 457     class Allocator : public virtual salhelper::SimpleReferenceObject
 458     {
 459     public:
 460         template< class T > T * construct()
 461         {
 462             void * page = 0; sal_uInt16 size = 0;
 463             if (allocate (&page, &size))
 464             {
 465                 return new(page) T(size);
 466             }
 467             return 0;
 468         }
 469
 470         bool allocate (void ** ppPage, sal_uInt16 * pnSize)
 471         {
 472             allocate_Impl (ppPage, pnSize);
 473             return ((*ppPage != 0) && (*pnSize != 0));
 474         }
 475
 476         void deallocate (void * pPage)
 477         {
 478             if (pPage != 0)
 479                 deallocate_Impl (pPage);
 480         }
 481
 482         static storeError createInstance (
 483             rtl::Reference< PageData::Allocator > & rxAllocator, sal_uInt16 nPageSize);
 484
 485     protected:
 486         virtual ~Allocator() {}
 487
 488     private:
 489         /** Implementation (abstract).
 490          */
 491         virtual void allocate_Impl (void ** ppPage, sal_uInt16 * pnSize) = 0;
 492         virtual void deallocate_Impl (void * pPage) = 0;
 493     };
 494
 495     static void* operator new (size_t, void * p) { return p; }
 496     static void  operator delete (void * , void *) {}
 497
 498     /** Construction.
 499      */
 500     explicit PageData (sal_uInt16 nPageSize = thePageSize)
 501         : m_aGuard(),
 502           m_aDescr(STORE_PAGE_NULL, nPageSize, thePageSize),
 503           m_aMarked(),
 504           m_aUnused()
 505     {}
 506
 507     void swap (PageData & rhs) // nothrow
 508     {
 509         m_aGuard.swap(rhs.m_aGuard);
 510         m_aDescr.swap(rhs.m_aDescr);
 511         m_aMarked.swap(rhs.m_aMarked);
 512         m_aUnused.swap(rhs.m_aUnused);
 513     }
 514
 515     PageData (PageData const & rhs) // nothrow
 516         : m_aGuard (rhs.m_aGuard),
 517           m_aDescr (rhs.m_aDescr),
 518           m_aMarked(rhs.m_aMarked),
 519           m_aUnused(rhs.m_aUnused)
 520     {}
 521
 522     PageData & operator= (PageData const & rhs) // nothrow
 523     {
 524         PageData tmp (rhs);
 525         swap (tmp);
 526         return *this;
 527     }
 528
 529     /** guard (external representation).
 530      */
 531     void guard (sal_uInt32 nAddr)
 532     {
 533         sal_uInt32 nCRC32 = 0;
 534         nCRC32 = rtl_crc32 (nCRC32, &m_aGuard.m_nMagic, sizeof(sal_uInt32));
 535         m_aDescr.m_nAddr = store::htonl(nAddr);
 536         nCRC32 = rtl_crc32 (nCRC32, &m_aDescr, theSize - sizeof(G));
 537         m_aGuard.m_nCRC32 = store::htonl(nCRC32);
 538     }
 539
 540     /** verify (external representation).
 541      */
 542     storeError verify (sal_uInt32 nAddr) const
 543     {
 544         sal_uInt32 nCRC32 = 0;
 545         nCRC32 = rtl_crc32 (nCRC32, &m_aGuard.m_nMagic, sizeof(sal_uInt32));
 546         nCRC32 = rtl_crc32 (nCRC32, &m_aDescr, theSize - sizeof(G));
 547         if (m_aGuard.m_nCRC32 != store::htonl(nCRC32))
 548             return store_E_InvalidChecksum;
 549         if (m_aDescr.m_nAddr != store::htonl(nAddr))
 550             return store_E_InvalidAccess;
 551         return store_E_None;
 552     }
 553
 554     storeError verifyVersion (sal_uInt32 nMagic) const
 555     {
 556         if (m_aGuard.m_nMagic != store::htonl(nMagic))
 557             return store_E_WrongVersion;
 558         else
 559             return store_E_None;
 560     }
 561 };
 562
 563 /*========================================================================
 564  *
 565  * PageHolder.
 566  *
 567  *======================================================================*/
 568 class PageHolder
 569 {
 570     SharedCount m_refcount;
 571     PageData  * m_pagedata;
 572
 573     typedef rtl::Reference< PageData::Allocator > allocator_type;
 574     allocator_type m_allocator;
 575
 576 public:
 577     explicit PageHolder (PageData * pagedata = 0, allocator_type const & allocator = allocator_type())
 578         : m_refcount (),
 579           m_pagedata (pagedata),
 580           m_allocator(allocator)
 581     {
 582         OSL_ENSURE((m_pagedata == 0) || m_allocator.is(), "store::PageHolder::ctor(): pagedata w/o allocator.");
 583     }
 584
 585     ~PageHolder()
 586     {
 587         if ((m_refcount == 1) && (m_pagedata != 0))
 588         {
 589             // free pagedata.
 590             OSL_ENSURE(m_allocator.is(), "store::PageHolder::dtor(): pagedata w/o allocator.");
 591             m_allocator->deallocate (m_pagedata);
 592         }
 593     }
 594
 595     void swap (PageHolder & rhs) // nothrow
 596     {
 597         m_refcount.swap(rhs.m_refcount);
 598         store::swap(m_pagedata,  rhs.m_pagedata);
 599         store::swap(m_allocator, rhs.m_allocator);
 600     }
 601
 602     PageHolder (PageHolder const & rhs) // nothrow
 603         : m_refcount (rhs.m_refcount),
 604           m_pagedata (rhs.m_pagedata),
 605           m_allocator(rhs.m_allocator)
 606     {}
 607
 608     PageHolder & operator= (PageHolder const & rhs) // nothrow
 609     {
 610         PageHolder tmp (rhs);
 611         swap(tmp);
 612         return *this;
 613     }
 614
 615     PageData * get() { return m_pagedata; }
 616     PageData const * get() const { return m_pagedata; }
 617
 618     PageData * operator->()
 619     {
 620         OSL_PRECOND(m_pagedata != 0, "store::PageHolder::operator->(): Null pointer");
 621         return m_pagedata;
 622     }
 623     PageData const * operator->() const
 624     {
 625         OSL_PRECOND(m_pagedata != 0, "store::PageHolder::operator->(): Null pointer");
 626         return m_pagedata;
 627     }
 628
 629     PageData & operator*()
 630     {
 631         OSL_PRECOND(m_pagedata != 0, "store::PageHolder::operator*(): Null pointer");
 632         return *m_pagedata;
 633     }
 634     PageData const & operator*() const
 635     {
 636         OSL_PRECOND(m_pagedata != 0, "store::PageHolder::operator*(): Null pointer");
 637         return *m_pagedata;
 638     }
 639 };
 640
 641 /*========================================================================
 642  *
 643  * PageHolderObject.
 644  *
 645  *======================================================================*/
 646 template< class T >
 647 class PageHolderObject
 648 {
 649     /** Representation.
 650      */
 651     PageHolder m_xPage;
 652
 653     /** Checked cast.
 654      */
 655     template< class U >
 656     static bool isA (PageData const * p)
 657     {
 658         return ((p != 0) && (p->type() == U::theTypeId));
 659     }
 660
 661     template< class U >
 662     static U * dynamic_page_cast (PageData * p)
 663     {
 664         return isA<U>(p) ? static_cast<U*>(p) : 0;
 665     }
 666
 667     template< class U >
 668     static U const * dynamic_page_cast (PageData const * p)
 669     {
 670         return isA<U>(p) ? static_cast<U const *>(p) : 0;
 671     }
 672
 673 public:
 674     bool construct (rtl::Reference< PageData::Allocator > const & rxAllocator)
 675     {
 676         if ((m_xPage.get() == 0) && rxAllocator.is())
 677         {
 678             PageHolder tmp (rxAllocator->construct<T>(), rxAllocator);
 679             m_xPage.swap (tmp);
 680         }
 681         return (m_xPage.get() != 0);
 682     }
 683
 684     static PageHolderObject<T> createInstance (rtl::Reference< PageData::Allocator > const & rxAllocator)
 685     {
 686         PageHolderObject<T> tmp;
 687         (void) tmp.construct (rxAllocator);
 688         return tmp;
 689     }
 690
 691     explicit PageHolderObject (PageHolder const & rxPage = PageHolder())
 692         : m_xPage (rxPage)
 693     {}
 694
 695     void swap (PageHolderObject<T> & rhs)
 696     {
 697         m_xPage.swap (rhs.m_xPage);
 698     }
 699
 700     PageHolderObject (PageHolderObject<T> const & rhs)
 701         : m_xPage (rhs.m_xPage)
 702     {}
 703
 704     PageHolderObject<T> & operator= (PageHolderObject<T> const & rhs)
 705     {
 706         PageHolderObject<T> tmp (rhs);
 707         this->swap (tmp);
 708         return *this;
 709     }
 710
 711     bool is() const
 712     {
 713         return (m_xPage.get() != 0);
 714     }
 715
 716 #if 1  /* EXP */
 717     PageHolder & get() { return m_xPage; }
 718     PageHolder const & get() const { return m_xPage; }
 719 #endif /* EXP */
 720
 721     T * operator->()
 722     {
 723         T * pImpl = dynamic_page_cast<T>(m_xPage.get());
 724         OSL_PRECOND(pImpl != 0, "store::PageHolder<T>::operator*(): Null pointer");
 725         return pImpl;
 726     }
 727     T const * operator->() const
 728     {
 729         T const * pImpl = dynamic_page_cast<T>(m_xPage.get());
 730         OSL_PRECOND(pImpl != 0, "store::PageHolder<T>::operator*(): Null pointer");
 731         return pImpl;
 732     }
 733
 734     T & operator*()
 735     {
 736         T * pImpl = dynamic_page_cast<T>(m_xPage.get());
 737         OSL_PRECOND(pImpl != 0, "store::PageHolder<T>::operator*(): Null pointer");
 738         return (*pImpl);
 739     }
 740     T const & operator*() const
 741     {
 742         T const * pImpl = dynamic_page_cast<T>(m_xPage.get());
 743         OSL_PRECOND(pImpl != 0, "store::PageHolder<T>::operator*(): Null pointer");
 744         return (*pImpl);
 745     }
 746
 747     static storeError guard (PageHolder & rxPage, sal_uInt32 nAddr)
 748     {
 749         PageData * pHead = rxPage.get();
 750         if (!pHead)
 751             return store_E_InvalidAccess;
 752         pHead->guard(nAddr);
 753
 754         T * pImpl = dynamic_page_cast<T>(pHead);
 755         OSL_PRECOND(pImpl != 0, "store::PageHolder<T>::guard(): Null pointer");
 756         pImpl->guard();
 757
 758         return store_E_None;
 759     }
 760     static storeError verify (PageHolder const & rxPage, sal_uInt32 nAddr)
 761     {
 762         PageData const * pHead = rxPage.get();
 763         if (!pHead)
 764             return store_E_InvalidAccess;
 765
 766         storeError eErrCode = pHead->verify(nAddr);
 767         if (eErrCode != store_E_None)
 768             return eErrCode;
 769
 770         T const * pImpl = dynamic_page_cast<T>(pHead);
 771         if (!pImpl)
 772             return store_E_WrongVersion;
 773
 774         return pImpl->verify();
 775     }
 776 };
 777
 778
 779 class OStorePageBIOS;
 780
 781 class OStorePageObject
 782 {
 783     typedef OStorePageData       page;
 784
 785 public:
 786     /** Allocation.
 787      */
 788     static void * operator new (size_t n)
 789     {
 790         return rtl_allocateMemory (sal_uInt32(n));
 791     }
 792     static void operator delete (void * p)
 793     {
 794         rtl_freeMemory (p);
 795     }
 796
 797     /** State.
 798      */
 799     inline bool dirty() const;
 800     inline void clean();
 801     inline void touch();
 802
 803     /** Location.
 804      */
 805     inline sal_uInt32 location() const;
 806     inline void       location (sal_uInt32 nAddr);
 807
 808 protected:
 809     /** Representation.
 810      */
 811     PageHolder m_xPage;
 812     bool       m_bDirty;
 813
 814     /** Construction.
 815      */
 816     explicit OStorePageObject (PageHolder const & rxPage = PageHolder())
 817         : m_xPage (rxPage), m_bDirty (false)
 818     {}
 819
 820     /** Destruction.
 821      */
 822     virtual ~OStorePageObject();
 823
 824 public:
 825     template< class U >
 826     PageHolderObject<U> makeHolder() const
 827     {
 828         return PageHolderObject<U>(m_xPage);
 829     }
 830
 831     template< class U >
 832     storeError construct (rtl::Reference< PageData::Allocator > const & rxAllocator)
 833     {
 834         if (!rxAllocator.is())
 835             return store_E_InvalidAccess;
 836
 837         PageHolder tmp (rxAllocator->construct<U>(), rxAllocator);
 838         if (!tmp.get())
 839             return store_E_OutOfMemory;
 840
 841         m_xPage.swap (tmp);
 842         return store_E_None;
 843     }
 844
 845     PageHolder & get() { return m_xPage; }
 846     PageHolder const & get() const { return m_xPage; }
 847
 848     virtual storeError guard  (sal_uInt32 nAddr) = 0;
 849     virtual storeError verify (sal_uInt32 nAddr) const = 0;
 850 };
 851
 852 inline bool OStorePageObject::dirty() const
 853 {
 854     return m_bDirty;
 855 }
 856
 857 inline void OStorePageObject::clean()
 858 {
 859     m_bDirty = false;
 860 }
 861
 862 inline void OStorePageObject::touch()
 863 {
 864     m_bDirty = true;
 865 }
 866
 867 inline sal_uInt32 OStorePageObject::location() const
 868 {
 869     return m_xPage->location();
 870 }
 871
 872 inline void OStorePageObject::location (sal_uInt32 nAddr)
 873 {
 874     m_xPage->location(nAddr);
 875     touch();
 876 }
 877
 878 /*========================================================================
 879  *
 880  * The End.
 881  *
 882  *======================================================================*/
 883
 884 } // namespace store
 885
 886 #endif // INCLUDED_STORE_SOURCE_STORBASE_HXX
 887
 888 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */