//
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// CacheSerializer.swift
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// Kingfisher
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//
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// Created by Wei Wang on 2016/09/02.
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//
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// Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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import Foundation
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import CoreGraphics
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/// An `CacheSerializer` is used to convert some data to an image object after
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/// retrieving it from disk storage, and vice versa, to convert an image to data object
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/// for storing to the disk storage.
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public protocol CacheSerializer {
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/// Gets the serialized data from a provided image
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/// and optional original data for caching to disk.
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///
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/// - Parameters:
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/// - image: The image needed to be serialized.
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/// - original: The original data which is just downloaded.
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/// If the image is retrieved from cache instead of
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/// downloaded, it will be `nil`.
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/// - Returns: The data object for storing to disk, or `nil` when no valid
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/// data could be serialized.
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func data(with image: KFCrossPlatformImage, original: Data?) -> Data?
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/// Gets an image from provided serialized data.
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///
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/// - Parameters:
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/// - data: The data from which an image should be deserialized.
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/// - options: The parsed options for deserialization.
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/// - Returns: An image deserialized or `nil` when no valid image
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/// could be deserialized.
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func image(with data: Data, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage?
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/// Gets an image deserialized from provided data.
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///
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/// - Parameters:
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/// - data: The data from which an image should be deserialized.
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/// - options: Options for deserialization.
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/// - Returns: An image deserialized or `nil` when no valid image
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/// could be deserialized.
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/// - Note:
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/// This method is deprecated. Please implement the version with
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/// `KingfisherParsedOptionsInfo` as parameter instead.
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@available(*, deprecated,
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message: "Deprecated. Implement the method with same name but with `KingfisherParsedOptionsInfo` instead.")
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func image(with data: Data, options: KingfisherOptionsInfo?) -> KFCrossPlatformImage?
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}
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extension CacheSerializer {
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public func image(with data: Data, options: KingfisherOptionsInfo?) -> KFCrossPlatformImage? {
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return image(with: data, options: KingfisherParsedOptionsInfo(options))
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}
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}
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/// Represents a basic and default `CacheSerializer` used in Kingfisher disk cache system.
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/// It could serialize and deserialize images in PNG, JPEG and GIF format. For
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/// image other than these formats, a normalized `pngRepresentation` will be used.
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public struct DefaultCacheSerializer: CacheSerializer {
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/// The default general cache serializer used across Kingfisher's cache.
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public static let `default` = DefaultCacheSerializer()
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/// The compression quality when converting image to a lossy format data. Default is 1.0.
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public var compressionQuality: CGFloat = 1.0
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/// Whether the original data should be preferred when serializing the image.
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/// If `true`, the input original data will be checked first and used unless the data is `nil`.
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/// In that case, the serialization will fall back to creating data from image.
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public var preferCacheOriginalData: Bool = false
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/// Creates a cache serializer that serialize and deserialize images in PNG, JPEG and GIF format.
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///
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/// - Note:
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/// Use `DefaultCacheSerializer.default` unless you need to specify your own properties.
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///
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public init() { }
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/// - Parameters:
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/// - image: The image needed to be serialized.
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/// - original: The original data which is just downloaded.
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/// If the image is retrieved from cache instead of
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/// downloaded, it will be `nil`.
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/// - Returns: The data object for storing to disk, or `nil` when no valid
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/// data could be serialized.
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///
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/// - Note:
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/// Only when `original` contains valid PNG, JPEG and GIF format data, the `image` will be
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/// converted to the corresponding data type. Otherwise, if the `original` is provided but it is not
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/// If `original` is `nil`, the input `image` will be encoded as PNG data.
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public func data(with image: KFCrossPlatformImage, original: Data?) -> Data? {
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if preferCacheOriginalData {
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return original ??
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image.kf.data(
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format: original?.kf.imageFormat ?? .unknown,
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compressionQuality: compressionQuality
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)
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} else {
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return image.kf.data(
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format: original?.kf.imageFormat ?? .unknown,
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compressionQuality: compressionQuality
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)
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}
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}
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/// Gets an image deserialized from provided data.
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///
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/// - Parameters:
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/// - data: The data from which an image should be deserialized.
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/// - options: Options for deserialization.
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/// - Returns: An image deserialized or `nil` when no valid image
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/// could be deserialized.
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public func image(with data: Data, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
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return KingfisherWrapper.image(data: data, options: options.imageCreatingOptions)
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}
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}
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