DiskCache

open class DiskCache

A specialized cache for storing data in disk. Based on Haneke Disk Cache and customized for the MapCache project.

  • Gets the root base folder to be used.

    Declaration

    Swift

    open class func baseURL() -> URL

  • URL of the physical folder of the Cache in the file system.

    Declaration

    Swift

    public let folderURL: URL

  • A shortcut for folderURL.path.

    Declaration

    Swift

    open var path: String { get }

  • Sum of the allocated size in disk for the cache expressed in bytes.

    Note that, this size is the actual disk allocation. It is equivalent with the amount of bytes that would become available on the volume if the directory is deleted.

    For example, a file may just contain 156 bytes of data (size listed in ls command), however its disk size is 4096, 1 volume block (as listed using du -h)

    This size is calculated each time

    Declaration

    Swift

    open var diskSize: UInt64

  • This is the sum of the data sizes of the files within the DiskCache

    This size is calculated each time it is used

    Seealso

    diskSize

    Declaration

    Swift

    open var fileSize: UInt64? { get }

  • Maximum allowed cache disk allocated size for this DiskCache Defaults to unlimited capacity (UINT64_MAX`)

    Declaration

    Swift

    open var capacity: UInt64 { get set }

  • Queue for making async operations.

    Declaration

    Swift

    open lazy var cacheQueue: DispatchQueue { get set }

  • Constructor

    Declaration

    Swift

    public init(withName cacheName: String, capacity: UInt64 = UINT64_MAX)

    Parameters

    withName

    Name of the cache, will be the subfolder name too.
    capacity

    capacity of the cache in bytes. Defaults to virutally unlimited capacity (UINT64_MAX)

  • Get the path for key.

    Declaration

    Swift

    open func path(forKey key: String) -> String

  • Sets the data for the key asyncronously. Use this function for writing into the cache.

    Declaration

    Swift

    open func setData(_ data: Data, forKey key: String)

  • Sets the data for the key synchronously.

    Declaration

    Swift

    open func setDataSync(_ data: Data, forKey key: String)

  • Fetches the image data from storage synchronously.

    Declaration

    Swift

    open func fetchDataSync(forKey key: String, failure fail: ((Error?) -> ())? = nil, success succeed: @escaping (Data) -> ())

    Parameters

    forKey

    Key within the cache
    failure

    closure to be run in case of error
    success

    closure to be run once the data is ready

  • Removes asynchronously the data from the diskcache for the key passed as argument.

    Declaration

    Swift

    open func removeData(withKey key: String)

    Parameters

    withKey

    key to be removed

  • Removes asynchronously all data from the cache. Calls completition closure once the task is done.

    Declaration

    Swift

    open func removeAllData(_ completion: (() -> ())? = nil)

    Parameters

    completition

    closure run once all the files are deleted from the cache

  • Removes the cache from the system. This method not only removes the data, it also removes the cache folder.

    Do not call any method after removing the cache, create a new instance instead.

    Declaration

    Swift

    open func removeCache()

  • Asynchronously updates the access date of a file.

    Declaration

    Swift

    open func updateAccessDate(_ getData: @autoclosure @escaping () -> Data?, key: String)

  • Calculates the size used by all the files in the cache.

    Declaration

    Swift

    public func calculateDiskSize() -> UInt64

Private

  • It checks if the capacity of the cache has been reached. If so, it removes the least recently used file (LRU).

    Declaration

    Swift

    fileprivate func controlCapacity()

  • Updates the time a file was accessed for the last time.

    Declaration

    Swift

    @discardableResult
fileprivate func updateDiskAccessDate(atPath path: String) -> Bool

  • Removes a file syncrhonously.

    Declaration

    Swift

    fileprivate func removeFile(atPath path: String)

  • Substracts from the cachesize the disk size passed as parameter. Logs an error message if the amount to be substracted is larger than the current used disk space.

    Declaration

    Swift

    fileprivate func substract(diskSize: UInt64)

    Parameters

    diskSize

    disksize to be deducted