C++ PageInit函数代码示例

initcode int PhysInit()
{
	DWORD maxPfn, memSize;
	
	PhysReadMemoryMap();

	maxPfn = GetMaxPfn();
		
	if (maxPfn >= PFN_MAX)
	{
		KePrint(KERN_INFO "PHYS: Your machine has more than 4GB of RAM. Limiting to 4GB for the moment.\n");
		maxPfn = PFN_MAX - 1;
	}
			
	PageEarlyInit(maxPfn);

	/* Print memory size for information purposes */
	memSize=(maxPfn >> 8);
	KePrint(KERN_INFO "PHYS: %umb physical memory available\n", memSize);

	if (memSize < 8)
		KernelPanic("Less than 8mb memory available. Whitix requires more than this\n");

	/* So that appropriate areas of the memory are reserved when setting up the page stack */
	DoReserveAreas(maxPfn);

	/* Set up the page allocation (memory/page_alloc.c) */
	PageInit();

	return 0;
}

void CocosGUIExamplesPageScene::onEnter()
{
    CCScene::onEnter();
    
    m_pUILayer = UILayer::create();
    m_pUILayer->scheduleUpdate();
    addChild(m_pUILayer);
    
    PageInit();
    
    CCSize winSize = CCDirector::sharedDirector()->getWinSize();
    
    UILabel* label = UILabel::create();
    label->setText("Move by horizontal direction");
    label->setFontName("Marker Felt");
    label->setFontSize(32);
    label->setAnchorPoint(ccp(0.5f, -1));
    label->setPosition(ccp(winSize.width / 2.0f, winSize.height / 2.0f + label->getContentSize().height * 1.5));
    m_pUILayer->addWidget(label);
    
    // left button
    UIButton* left_button = UIButton::create();
    left_button->setTouchEnable(true);
    left_button->loadTextures("cocosgui/UITest/b1.png", "cocosgui/UITest/b2.png", "");
    float left_button_width = left_button->getContentSize().width;
    left_button->setPosition(ccp(left_button_width - left_button_width / 2, m_pUILayer->getContentSize().height / 2));
    left_button->addReleaseEvent(this, coco_releaseselector(CocosGUIExamplesPageScene::toCocosGUIExamplesMapScene));
    m_pUILayer->addWidget(left_button);
}

void CocosGUIExamplesPageScene::onEnter()
{
    CCScene::onEnter();
    
    m_pUILayer = TouchGroup::create();
    m_pUILayer->scheduleUpdate();
    addChild(m_pUILayer);
    
    PageInit();
    
    CCSize winSize = CCDirector::sharedDirector()->getWinSize();
    
    gui::Label* label = gui::Label::create();
    label->setText("Move by horizontal direction");
    const char* font =
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    // custom ttf files are defined in Test-info.plist
    "Marker Felt";
#else
    "fonts/Marker Felt.ttf";
#endif
    label->setFontName(font);
    label->setFontSize(32);
    label->setAnchorPoint(ccp(0.5f, -1));
    label->setPosition(ccp(winSize.width / 2.0f, winSize.height / 2.0f + label->getSize().height * 1.5));
    m_pUILayer->addWidget(label);
    
    // exit button
    Button* exit_button = Button::create();
    exit_button->setTouchEnabled(true);
    exit_button->loadTextures("CloseNormal.png", "CloseSelected.png", "");
    exit_button->setPosition(ccp(m_pUILayer->getContentSize().width - exit_button->getSize().width, exit_button->getSize().height));
    exit_button->addTouchEventListener(this, toucheventselector(CocosGUIExamplesPageScene::menuCloseCallback));
    m_pUILayer->addWidget(exit_button);
}

/*
 * Initialize a page with the given type.
 *
 * Caller is responsible for marking it dirty, as appropriate.
 */
void
brin_page_init(Page page, uint16 type)
{
	PageInit(page, BLCKSZ, sizeof(BrinSpecialSpace));

	BrinPageType(page) = type;
}

/*
 * SetMatViewToPopulated
 *		Indicate that the materialized view has been populated by its query.
 *
 * NOTE: The heap starts out in a state that doesn't look scannable, and can
 * only transition from there to scannable at the time a new heap is created.
 *
 * NOTE: caller must be holding an appropriate lock on the relation.
 */
void
SetMatViewToPopulated(Relation relation)
{
	Page        page;

	Assert(relation->rd_rel->relkind == RELKIND_MATVIEW);
	Assert(relation->rd_ispopulated == false);

	page = (Page) palloc(BLCKSZ);
	PageInit(page, BLCKSZ, 0);

	if (RelationNeedsWAL(relation))
		log_newpage(&(relation->rd_node), MAIN_FORKNUM, 0, page);

	RelationOpenSmgr(relation);

	PageSetChecksumInplace(page, 0);
	smgrextend(relation->rd_smgr, MAIN_FORKNUM, 0, (char *) page, true);

	pfree(page);

	smgrimmedsync(relation->rd_smgr, MAIN_FORKNUM);

	RelationCacheInvalidateEntry(relation->rd_id);
}

/*
 * XLogRecordPageWithFreeSpace - like RecordPageWithFreeSpace, for use in
 *		WAL replay
 */
void
XLogRecordPageWithFreeSpace(RelFileNode rnode, BlockNumber heapBlk,
							Size spaceAvail)
{
	int			new_cat = fsm_space_avail_to_cat(spaceAvail);
	FSMAddress	addr;
	uint16		slot;
	BlockNumber blkno;
	Buffer		buf;
	Page		page;

	/* Get the location of the FSM byte representing the heap block */
	addr = fsm_get_location(heapBlk, &slot);
	blkno = fsm_logical_to_physical(addr);

	/* If the page doesn't exist already, extend */
	buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR);
	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);

	page = BufferGetPage(buf);
	if (PageIsNew(page))
		PageInit(page, BLCKSZ, 0);

	if (fsm_set_avail(page, slot, new_cat))
		MarkBufferDirtyHint(buf, false);
	UnlockReleaseBuffer(buf);
}

/*
 * Ensure that the visibility map fork is at least vm_nblocks long, extending
 * it if necessary with zeroed pages.
 */
static void
vm_extend(Relation rel, BlockNumber vm_nblocks)
{
	BlockNumber vm_nblocks_now;
	Page		pg;

	pg = (Page) palloc(BLCKSZ);
	PageInit(pg, BLCKSZ, 0);

	/*
	 * We use the relation extension lock to lock out other backends trying to
	 * extend the visibility map at the same time. It also locks out extension
	 * of the main fork, unnecessarily, but extending the visibility map
	 * happens seldom enough that it doesn't seem worthwhile to have a
	 * separate lock tag type for it.
	 *
	 * Note that another backend might have extended or created the relation
	 * by the time we get the lock.
	 */
	LockRelationForExtension(rel, ExclusiveLock);

	/* Might have to re-open if a cache flush happened */
	RelationOpenSmgr(rel);

	/*
	 * Create the file first if it doesn't exist.  If smgr_vm_nblocks is
	 * positive then it must exist, no need for an smgrexists call.
	 */
	if ((rel->rd_smgr->smgr_vm_nblocks == 0 ||
		 rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber) &&
		!smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
		smgrcreate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, false);

	vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM);

	/* Now extend the file */
	while (vm_nblocks_now < vm_nblocks)
	{
		smgrextend(rel->rd_smgr, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
				   (char *) pg, false);
		vm_nblocks_now++;
	}

	/*
	 * Send a shared-inval message to force other backends to close any smgr
	 * references they may have for this rel, which we are about to change.
	 * This is a useful optimization because it means that backends don't have
	 * to keep checking for creation or extension of the file, which happens
	 * infrequently.
	 */
	CacheInvalidateSmgr(rel->rd_smgr->smgr_rnode);

	/* Update local cache with the up-to-date size */
	rel->rd_smgr->smgr_vm_nblocks = vm_nblocks_now;

	UnlockRelationForExtension(rel, ExclusiveLock);

	pfree(pg);
}

void
SpGistInitPage(Page page, uint16 f, Size pageSize)
{
    SpGistPageOpaque opaque;
    PageInit(page, pageSize, sizeof(SpGistPageOpaqueData));
    opaque = SpGistPageGetOpaque(page);
    memset(opaque, 0, sizeof(SpGistPageOpaqueData));
    opaque->flags = f;
}

void PageFree(Chunk chunk, Index pi)
{
  AVERT(Chunk, chunk);
  AVER(pi >= chunk->allocBase);
  AVER(pi < chunk->pages);
  AVER(BTGet(chunk->allocTable, pi));

  PageInit(chunk, pi);
}

/*
 * _bitmap_init_lovpage -- initialize a new LOV page.
 */
void
_bitmap_init_lovpage(Relation rel __attribute__((unused)), Buffer buf)
{
	Page			page;

	page = (Page) BufferGetPage(buf);

	if(PageIsNew(page))
		PageInit(page, BufferGetPageSize(buf), 0);
}

/*
 * Initialize a page with the given type.
 *
 * Caller is responsible for marking it dirty, as appropriate.
 */
void
brin_page_init(Page page, uint16 type)
{
	BrinSpecialSpace *special;

	PageInit(page, BLCKSZ, sizeof(BrinSpecialSpace));

	special = (BrinSpecialSpace *) PageGetSpecialPointer(page);
	special->type = type;
}

/*
 * Initialize an SPGiST page to empty, with specified flags
 */
void
SpGistInitPage(Page page, uint16 f)
{
	SpGistPageOpaque opaque;

	PageInit(page, BLCKSZ, MAXALIGN(sizeof(SpGistPageOpaqueData)));
	opaque = SpGistPageGetOpaque(page);
	memset(opaque, 0, sizeof(SpGistPageOpaqueData));
	opaque->flags = f;
	opaque->spgist_page_id = SPGIST_PAGE_ID;
}

void
BloomInitPage(Page page, uint16 f, Size pageSize)
{
    BloomPageOpaque opaque;
	 
	PageInit(page, pageSize, sizeof(BloomPageOpaqueData));
		  
	opaque = BloomPageGetOpaque(page);
	memset(opaque, 0, sizeof(BloomPageOpaqueData));
	opaque->maxoff = 0;
	opaque->flags = f;
}

/*
 * Initialize bloom page.
 */
void
BloomInitPage(Page page, uint16 flags)
{
	BloomPageOpaque opaque;

	PageInit(page, BLCKSZ, sizeof(BloomPageOpaqueData));

	opaque = BloomPageGetOpaque(page);
	memset(opaque, 0, sizeof(BloomPageOpaqueData));
	opaque->flags = flags;
	opaque->bloom_page_id = BLOOM_PAGE_ID;
}

void
GinInitPage(Page page, uint32 f, Size pageSize)
{
	GinPageOpaque opaque;

	PageInit(page, pageSize, sizeof(GinPageOpaqueData));

	opaque = GinPageGetOpaque(page);
	memset(opaque, 0, sizeof(GinPageOpaqueData));
	opaque->flags = f;
	opaque->rightlink = InvalidBlockNumber;
}