108 lines
3.5 KiB
Swift
108 lines
3.5 KiB
Swift
//
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// WebViewProvider.swift
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// NetNewsWire-iOS
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//
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// Created by Maurice Parker on 9/21/19.
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// Copyright © 2019 Ranchero Software. All rights reserved.
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//
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import Foundation
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import RSCore
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import WebKit
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/// WKWebView has an awful behavior of a flash to white on first load when in dark mode.
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/// Keep a queue of WebViews where we've already done a trivial load so that by the time we need them in the UI, they're past the flash-to-shite part of their lifecycle.
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class WebViewProvider: NSObject {
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private let articleIconSchemeHandler: ArticleIconSchemeHandler
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private let operationQueue = MainThreadOperationQueue()
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private var queue = NSMutableArray()
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init(coordinator: SceneCoordinator) {
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articleIconSchemeHandler = ArticleIconSchemeHandler(coordinator: coordinator)
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super.init()
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replenishQueueIfNeeded()
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}
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func replenishQueueIfNeeded() {
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operationQueue.add(WebViewProviderReplenishQueueOperation(queue: queue, articleIconSchemeHandler: articleIconSchemeHandler))
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}
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func dequeueWebView(completion: @escaping (PreloadedWebView) -> ()) {
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operationQueue.add(WebViewProviderDequeueOperation(queue: queue, articleIconSchemeHandler: articleIconSchemeHandler, completion: completion))
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operationQueue.add(WebViewProviderReplenishQueueOperation(queue: queue, articleIconSchemeHandler: articleIconSchemeHandler))
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}
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}
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class WebViewProviderReplenishQueueOperation: MainThreadOperation {
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// MainThreadOperation
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public var isCanceled = false
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public var id: Int?
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public weak var operationDelegate: MainThreadOperationDelegate?
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public var name: String? = "WebViewProviderReplenishQueueOperation"
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public var completionBlock: MainThreadOperation.MainThreadOperationCompletionBlock?
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private let minimumQueueDepth = 3
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private var queue: NSMutableArray
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private var articleIconSchemeHandler: ArticleIconSchemeHandler
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init(queue: NSMutableArray, articleIconSchemeHandler: ArticleIconSchemeHandler) {
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self.queue = queue
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self.articleIconSchemeHandler = articleIconSchemeHandler
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}
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func run() {
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while queue.count < minimumQueueDepth {
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let webView = PreloadedWebView(articleIconSchemeHandler: articleIconSchemeHandler)
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queue.insert(webView, at: 0)
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webView.preload()
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}
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self.operationDelegate?.operationDidComplete(self)
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}
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}
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class WebViewProviderDequeueOperation: MainThreadOperation {
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// MainThreadOperation
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public var isCanceled = false
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public var id: Int?
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public weak var operationDelegate: MainThreadOperationDelegate?
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public var name: String? = "WebViewProviderFlushQueueOperation"
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public var completionBlock: MainThreadOperation.MainThreadOperationCompletionBlock?
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private var queue: NSMutableArray
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private var articleIconSchemeHandler: ArticleIconSchemeHandler
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private var completion: (PreloadedWebView) -> ()
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init(queue: NSMutableArray, articleIconSchemeHandler: ArticleIconSchemeHandler, completion: @escaping (PreloadedWebView) -> ()) {
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self.queue = queue
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self.articleIconSchemeHandler = articleIconSchemeHandler
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self.completion = completion
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}
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func run() {
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if let webView = queue.lastObject as? PreloadedWebView {
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webView.ready { preloadedWebView in
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self.completion(preloadedWebView)
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self.queue.remove(webView)
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}
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self.operationDelegate?.operationDidComplete(self)
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return
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}
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assertionFailure("Creating PreloadedWebView in \(#function); queue has run dry.")
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let webView = PreloadedWebView(articleIconSchemeHandler: articleIconSchemeHandler)
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webView.preload()
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webView.ready { preloadedWebView in
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self.completion(preloadedWebView)
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}
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self.operationDelegate?.operationDidComplete(self)
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}
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}
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