interface ICache in Tinman.Core.Caching

Base interface for cache-like data structures with extended functionality.

interface	ICache	with	<TId>
		extends	ICacheBase<TId>
		base of	LruCache

Remarks

This interface is based on ICacheBase, and provides additional features:

• Loading and unloading of cache pages can be forwarded to an aggregated ICacheCallback object.
• Cache pages can be locked (see LockPage and UnlockPage), to prevent them from being evicted.
• Cache pages can be loaded partially (see Partial).

Attributes

Capacity

The capacity of this cache.

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

InvalidId

The page ID value that represents non-existent mappings.

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

Oldest

Returns the index of the oldest cache page.

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

Methods

EvictAll

Evicts all pages from the cache.

method	EvictAll ()
inherited	ICacheBase.EvictAll

EvictId

Evicts the given page from the cache.

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

Remarks:

Requesting the given page later will cause a cache miss.

EvictIndex

Evicts the given page from the cache.

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

Remarks:

Requesting the given page later will cause a cache miss.

Fetch

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

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.
inherited	ICacheBase.Fetch

---

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

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.

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.

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

Remarks:

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

GetIndex

Returns the cache page index of the given page.

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.
inherited	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?

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.

See also:

LockPage
UnlockPage

IsPartial

Has the given page been partially loaded?

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.

See also:

PageLoadFlags.Partial

LockPage

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

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

See also:

UnlockPage

UnlockPage

Unlocks a previously locked cache page.

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

See also:

LockPage

Use

The given cache page has been used.

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

Remarks:

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