iOS SDWebImage清理缓存数据

- (float)checkTmpSize
{
float totalSize = 0;
NSDirectoryEnumerator *fileEnumerator = [[NSFileManager defaultManager] enumeratorAtPath:_diskCachePath];
for (NSString *fileName in fileEnumerator)
{
NSString *filePath = [_diskCachePath stringByAppendingPathComponent:fileName];

NSDictionary *attrs = [[NSFileManager defaultManager] attributesOfItemAtPath:filePath error:nil];

unsigned long long length = [attrs fileSize];

totalSize += length / 1024.0 / 1024.0;
}
// NSLog(@"tmp size is %.2f",totalSize);

return totalSize;
}