ifish/Ifish/YYWebImage/Cache/YYMemoryCache.h

214 lines
6.9 KiB
Objective-C

//
// YYMemoryCache.h
// YYCache <https://github.com/ibireme/YYCache>
//
// Created by ibireme on 15/2/7.
// Copyright (c) 2015 ibireme.
//
// This source code is licensed under the MIT-style license found in the
// LICENSE file in the root directory of this source tree.
//
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
/**
YYMemoryCache is a fast in-memory cache that stores key-value pairs.
In contrast to NSDictionary, keys are retained and not copied.
The API and performance is similar to `NSCache`, all methods are thread-safe.
YYMemoryCache objects differ from NSCache in a few ways:
* It uses LRU (least-recently-used) to remove objects; NSCache's eviction method
is non-deterministic.
* It can be controlled by cost, count and age; NSCache's limits are imprecise.
* It can be configured to automatically evict objects when receive memory
warning or app enter background.
The time of `Access Methods` in YYMemoryCache is typically in constant time (O(1)).
*/
@interface YYMemoryCache : NSObject
#pragma mark - Attribute
///=============================================================================
/// @name Attribute
///=============================================================================
/** The name of the cache. Default is nil. */
@property (nullable, copy) NSString *name;
/** The number of objects in the cache (read-only) */
@property (readonly) NSUInteger totalCount;
/** The total cost of objects in the cache (read-only). */
@property (readonly) NSUInteger totalCost;
#pragma mark - Limit
///=============================================================================
/// @name Limit
///=============================================================================
/**
The maximum number of objects the cache should hold.
@discussion The default value is NSUIntegerMax, which means no limit.
This is not a strict limit—if the cache goes over the limit, some objects in the
cache could be evicted later in backgound thread.
*/
@property NSUInteger countLimit;
/**
The maximum total cost that the cache can hold before it starts evicting objects.
@discussion The default value is NSUIntegerMax, which means no limit.
This is not a strict limit—if the cache goes over the limit, some objects in the
cache could be evicted later in backgound thread.
*/
@property NSUInteger costLimit;
/**
The maximum expiry time of objects in cache.
@discussion The default value is DBL_MAX, which means no limit.
This is not a strict limit—if an object goes over the limit, the object could
be evicted later in backgound thread.
*/
@property NSTimeInterval ageLimit;
/**
The auto trim check time interval in seconds. Default is 5.0.
@discussion The cache holds an internal timer to check whether the cache reaches
its limits, and if the limit is reached, it begins to evict objects.
*/
@property NSTimeInterval autoTrimInterval;
/**
If `YES`, the cache will remove all objects when the app receives a memory warning.
The default value is `YES`.
*/
@property BOOL shouldRemoveAllObjectsOnMemoryWarning;
/**
If `YES`, The cache will remove all objects when the app enter background.
The default value is `YES`.
*/
@property BOOL shouldRemoveAllObjectsWhenEnteringBackground;
/**
A block to be executed when the app receives a memory warning.
The default value is nil.
*/
@property (nullable, copy) void(^didReceiveMemoryWarningBlock)(YYMemoryCache *cache);
/**
A block to be executed when the app enter background.
The default value is nil.
*/
@property (nullable, copy) void(^didEnterBackgroundBlock)(YYMemoryCache *cache);
/**
If `YES`, the key-value pair will be released on main thread, otherwise on
background thread. Default is NO.
@discussion You may set this value to `YES` if the key-value object contains
the instance which should be released in main thread (such as UIView/CALayer).
*/
@property BOOL releaseOnMainThread;
/**
If `YES`, the key-value pair will be released asynchronously to avoid blocking
the access methods, otherwise it will be released in the access method
(such as removeObjectForKey:). Default is YES.
*/
@property BOOL releaseAsynchronously;
#pragma mark - Access Methods
///=============================================================================
/// @name Access Methods
///=============================================================================
/**
Returns a Boolean value that indicates whether a given key is in cache.
@param key An object identifying the value. If nil, just return `NO`.
@return Whether the key is in cache.
*/
- (BOOL)containsObjectForKey:(id)key;
/**
Returns the value associated with a given key.
@param key An object identifying the value. If nil, just return nil.
@return The value associated with key, or nil if no value is associated with key.
*/
- (nullable id)objectForKey:(id)key;
/**
Sets the value of the specified key in the cache (0 cost).
@param object The object to be stored in the cache. If nil, it calls `removeObjectForKey:`.
@param key The key with which to associate the value. If nil, this method has no effect.
@discussion Unlike an NSMutableDictionary object, a cache does not copy the key
objects that are put into it.
*/
- (void)setObject:(nullable id)object forKey:(id)key;
/**
Sets the value of the specified key in the cache, and associates the key-value
pair with the specified cost.
@param object The object to store in the cache. If nil, it calls `removeObjectForKey`.
@param key The key with which to associate the value. If nil, this method has no effect.
@param cost The cost with which to associate the key-value pair.
@discussion Unlike an NSMutableDictionary object, a cache does not copy the key
objects that are put into it.
*/
- (void)setObject:(nullable id)object forKey:(id)key withCost:(NSUInteger)cost;
/**
Removes the value of the specified key in the cache.
@param key The key identifying the value to be removed. If nil, this method has no effect.
*/
- (void)removeObjectForKey:(id)key;
/**
Empties the cache immediately.
*/
- (void)removeAllObjects;
#pragma mark - Trim
///=============================================================================
/// @name Trim
///=============================================================================
/**
Removes objects from the cache with LRU, until the `totalCount` is below or equal to
the specified value.
@param count The total count allowed to remain after the cache has been trimmed.
*/
- (void)trimToCount:(NSUInteger)count;
/**
Removes objects from the cache with LRU, until the `totalCost` is or equal to
the specified value.
@param cost The total cost allowed to remain after the cache has been trimmed.
*/
- (void)trimToCost:(NSUInteger)cost;
/**
Removes objects from the cache with LRU, until all expiry objects removed by the
specified value.
@param age The maximum age (in seconds) of objects.
*/
- (void)trimToAge:(NSTimeInterval)age;
@end
NS_ASSUME_NONNULL_END