硬盘缓存(YYDiskCache)

硬盘缓存(YYDiskCache)

采用的是文件和数据库相互配合的方式.

有一个参数inlineThreshold,默认20KB,小于它存数据库,大于它存文件.能获得效率的提高.

key:path,value:cache存储在NSMapTable里.根据path获得cache,进行一系列的set,get,remove操作

更底层的是YYKVStorage,它能直接对sqlite和文件系统进行读写.

每次内存超过限制时,select key, filename, size from manifest order by last_access_time desc limit ?1

会根据时间排序来删除最近不常用的数据.

硬盘访问的时间比较长,如果用OSSpinLockLock锁会造成CPU消耗过大,所以用的dispatch_semaphore_wait来做.

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NSString *basePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES) firstObject];

basePath = [basePath stringByAppendingPathComponent:@"FileCacheBenchmarkLarge"];

//  写入数据

//YYKVStorage能直接对sqlite和文件系统进行读写

YYKVStorage *yykvFile = [[YYKVStorage alloc] initWithPath:[basePath stringByAppendingPathComponent:@"yykvFile"] type:YYKVStorageTypeFile];

[yykvFile saveItemWithKey:keys[i] value:[NSKeyedArchiver archivedDataWithRootObject:values[i]] filename:keys[i] extendedData:nil];

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YYKVStorage *yykvSQLite = [[YYKVStorage alloc] initWithPath:[basePath stringByAppendingPathComponent:@"yykvSQLite"] type:YYKVStorageTypeSQLite];

[yykvSQLite saveItemWithKey:keys[i] value:[NSKeyedArchiver archivedDataWithRootObject:values[i]]];

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//YYDiskCache硬盘缓存   封装了YYKVStorage  有一个参数inlineThreshold,默认20KB,小于它存数据库,大于它存文件.能获得效率的提高.key:path,value:cache存储在NSMapTable里.根据path获得cache,进行一系列的set,get,remove操作

YYDiskCache *yy = [[YYDiskCache alloc] initWithPath:[basePath stringByAppendingPathComponent:@"yy"]];

yy.customArchiveBlock = ^(id object) {return object;};

yy.customUnarchiveBlock = ^(NSData *object) {returnobject;};

[yy setObject:values[i] forKey:keys[i]];

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//  读数据

NSString *basePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES) firstObject];

basePath = [basePath stringByAppendingPathComponent:@"FileCacheBenchmarkLarge"];

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YYKVStorage *yykvFile = [[YYKVStorage alloc] initWithPath:[basePath stringByAppendingPathComponent:@"yykvFile"] type:YYKVStorageTypeFile];

for (int i = 0; i < count; i++) {

YYKVStorageItem *item = [yykvFile getItemForKey:keys[i]];

NSData *value = item.value;

if (!value) printf("error!");

}

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YYKVStorage *yykvSQLite = [[YYKVStorage alloc] initWithPath:[basePath stringByAppendingPathComponent:@"yykvSQLite"] type:YYKVStorageTypeSQLite];

for (int i = 0; i < count; i++) {

YYKVStorageItem *item = [yykvSQLite getItemForKey:keys[i]];

NSData *value = item.value;

if (!value) printf("error!");

}

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YYDiskCache *yy = [[YYDiskCache alloc] initWithPath:[basePath stringByAppendingPathComponent:@"yy"]];

yy.customArchiveBlock = ^(id object) {return object;};

yy.customUnarchiveBlock = ^(NSData *object) {return object;};

for (int i = 0; i < count; i++) {

NSData *value = (id)[yy objectForKey:keys[i]];

if (!value) printf("error!");

}