forked from shadowfacts/Tusker
92 lines
2.7 KiB
Swift
92 lines
2.7 KiB
Swift
//
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// ImageCache.swift
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// Tusker
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//
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// Created by Shadowfacts on 8/21/18.
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// Copyright © 2018 Shadowfacts. All rights reserved.
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//
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import UIKit
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import Cache
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class ImageCache {
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static let avatars = ImageCache(name: "Avatars")
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static let headers = ImageCache(name: "Headers")
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static let attachments = ImageCache(name: "Attachments", diskExpiry: .seconds(60 * 60), memoryExpiry: .seconds(60))
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let storage: Storage<UIImage>
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var requests = [URL: Request]()
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init(name: String, diskExpiry: Expiry = .seconds(60 * 60 * 24), memoryExpiry: Expiry = .seconds(60 * 60)) {
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self.storage = try! Storage(
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diskConfig: DiskConfig(name: name, expiry: diskExpiry),
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memoryConfig: MemoryConfig(expiry: memoryExpiry),
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transformer: TransformerFactory.forImage())
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}
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func get(_ url: URL, completion: ((UIImage?) -> Void)?) {
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let key = url.absoluteString
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if (try? storage.existsObject(forKey: key)) ?? false,
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let image = try? storage.object(forKey: key) {
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completion?(image)
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} else {
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if let completion = completion, let request = requests[url] {
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request.callbacks.append(completion)
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} else {
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let request = Request(url: url, completion: completion)
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requests[url] = request
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request.run { (image) in
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try? self.storage.setObject(image, forKey: key)
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}
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}
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}
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}
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func get(_ url: URL) -> UIImage? {
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return try? storage.object(forKey: url.absoluteString)
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}
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func cancel(_ url: URL) {
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requests[url]?.cancel()
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}
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class Request {
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let url: URL
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var task: URLSessionDataTask?
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var callbacks: [(UIImage?) -> Void]
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init(url: URL, completion: ((UIImage?) -> Void)?) {
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if let completion = completion {
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self.callbacks = [completion]
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} else {
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self.callbacks = []
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}
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self.url = url
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}
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func run(cache: @escaping (UIImage) -> Void) {
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task = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
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guard error == nil, let data = data, let image = UIImage(data: data) else {
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self.complete(with: nil)
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return
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}
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cache(image)
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self.complete(with: image)
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})
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task!.resume()
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}
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func cancel() {
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task?.cancel()
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complete(with: nil)
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}
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func complete(with image: UIImage?) {
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callbacks.forEach { $0(image) }
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}
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}
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}
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