class LruCache in Tinman.Core.Caching

A cache that uses a simple LRU (least-recently-used) replacement scheme.

sealed class	LruCache	with	<TId>
		implements	ICache<TId>

Public / Attributes

Capacity

The capacity of this cache.

public property	Capacity { get }
type	int32
value	[>0]	The maximum number of entries this cache can hold.
implements	ICacheBase.Capacity

InvalidId

The page ID value that represents non-existent mappings.

public property	InvalidId { get }
type	TId
value		The invalid page ID value.
implements	ICacheBase.InvalidId

Oldest

Returns the index of the oldest cache page.

public property	Oldest { get }
type	int32
value	[-1..Capacity-1]	Index of the least-recently used cache page or -1 if all pages are unused.
implements	ICacheBase.Oldest

Public / Constructors

LruCache

Creates a new instance of LruCache.

public constructor	LruCache (int32 capacity, ICacheCallback<TId> callback = null, TId invalidId = default(TId), EqualsDelegate<TId> equals = null, HashCodeDelegate<TId> hashCode = null)
params	capacity	[>0]	The cache capacity.
	callback		Optional cache callback. If null, using the Partial will have no effect. Defaults to null.
	invalidId		The page ID value that represents an invalid page ID. Unused cached slots will be set to this value.
	equals		The equality delegate. Defaults to null.
	hashCode		Optional hash code delegate. Defaults to null.

Public / Methods

EvictAll

Evicts all pages from the cache.

public method	EvictAll ()
implements	ICacheBase.EvictAll

EvictId

Evicts the given page from the cache.

public method	EvictId (TId pageId)
params	pageId		The cache page ID.
implements	ICacheBase.EvictId

Remarks:

Requesting the given page later will cause a cache miss.

EvictIndex

Evicts the given page from the cache.

public method	EvictIndex (int32 pageIndex)
params	pageIndex	[0..Capacity-1]	The cache page index.
implements	ICacheBase.EvictIndex

Remarks:

Requesting the given page later will cause a cache miss.

Fetch

Fetches a page from the cache, loading it if necessary.

public method	Fetch (TId pageId)
type	int32
params	pageId		The page ID.
returns			[>=0]: The page is present in the cache, the return value is its index. [<=-1]: The page is not present in the cache and shall be loaded into the cache using the page index given by -1-value, where value is the value that is returned by this method.
implements	ICacheBase.Fetch

---

Fetches a page from the cache, loading it if necessary.

public method	Fetch (TId pageId, PageLoadFlags loadFlags, bool keepLocked)
type	int32
params	pageId		The page ID.
	loadFlags		The flags that determine how to load the cache page. When set to Manual, cache page loading will not be performed. The calling code must load the cache page in this case.
	keepLocked		Keep the cache page in locked state after fetching it (see LockPage)?
returns			[>=0]: The page is present in the cache, the return value is its index. [<=-1]: The page is not present in the cache and shall be loaded into the cache using the page index given by -1-return.
implements	ICache.Fetch

Remarks:

When this method returns, all necessary calls to CachePageChoose and CachePageData will have been done.

GetId

Returns the page ID of the given page.

public method	GetId (int32 pageIndex)
type	TId
params	pageIndex	[0..Capacity-1]	The page index.
returns			The page ID.
implements	ICacheBase.GetId

Remarks:

The state of the cache is not modified by this method.

GetIndex

Returns the cache page index of the given page.

public method	GetIndex (TId pageId, bool hitPage = false)
type	int32
params	pageId		The page ID.
	hitPage		Update state of the cache by hitting the page if it exists?
returns		[>=-1]	The cache page index or -1.
implements	ICacheBase.GetIndex

Remarks:

The state of the cache is not modified by this method if hitPage is false.

IsPageLocked

Is the given cache page locked?

public method	IsPageLocked (int32 pageIndex)
type	bool
params	pageIndex	[0..Capacity-1]	Index of page to unlock.
returns			true if the cache page is locked, false if not.
implements	ICache.IsPageLocked

See also:

ICache.LockPage
ICache.UnlockPage

IsPartial

Has the given page been partially loaded?

public method	IsPartial (int32 pageIndex)
type	bool
params	pageIndex	[0..Capacity-1]	The page index.
returns			true if the given page has been loaded partially, false if the page is either fully loaded or non-existent.
implements	ICache.IsPartial

See also:

PageLoadFlags.Partial

LockPage

Locks a cache page so that it will not be evicted from the cache by future calls.

public method	LockPage (int32 pageIndex)
params	pageIndex	[0..Capacity-1]	Index of page to lock.
implements	ICache.LockPage

See also:

ICache.UnlockPage

UnlockPage

Unlocks a previously locked cache page.

public method	UnlockPage (int32 pageIndex)
params	pageIndex	[0..Capacity-1]	Index of page to unlock.
implements	ICache.UnlockPage

See also:

ICache.LockPage

Use

The given cache page has been used.

public method	Use (int32 pageIndex)
params	pageIndex	[0..Capacity-1]	The page index.
implements	ICacheBase.Use

Remarks:

Use this method to avoid specific pages to get evicted from the cache too soon.