317 lines
9.5 KiB
Swift
317 lines
9.5 KiB
Swift
//
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// FaviconDownloader.swift
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// NetNewsWire
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//
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// Created by Brent Simmons on 11/19/17.
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// Copyright © 2017 Ranchero Software. All rights reserved.
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//
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import Foundation
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import CoreServices
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import Articles
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import Account
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import RSCore
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import UniformTypeIdentifiers
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extension Notification.Name {
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static let FaviconDidBecomeAvailable = Notification.Name("FaviconDidBecomeAvailableNotification") // userInfo key: FaviconDownloader.UserInfoKey.faviconURL
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}
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final class FaviconDownloader {
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private static let saveQueue = CoalescingQueue(name: "Cache Save Queue", interval: 1.0)
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private let folder: String
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private let diskCache: BinaryDiskCache
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private var singleFaviconDownloaderCache = [String: SingleFaviconDownloader]() // faviconURL: SingleFaviconDownloader
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private var remainingFaviconURLs = [String: ArraySlice<String>]() // homePageURL: array of faviconURLs that haven't been checked yet
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private var currentHomePageHasOnlyFaviconICO = false
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private var homePageToFaviconURLCache = [String: String]() //homePageURL: faviconURL
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private var homePageToFaviconURLCachePath: String
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private var homePageToFaviconURLCacheDirty = false {
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didSet {
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queueSaveHomePageToFaviconURLCacheIfNeeded()
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}
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}
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private var homePageURLsWithNoFaviconURLCache = Set<String>()
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private var homePageURLsWithNoFaviconURLCachePath: String
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private var homePageURLsWithNoFaviconURLCacheDirty = false {
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didSet {
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queueSaveHomePageURLsWithNoFaviconURLCacheIfNeeded()
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}
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}
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private let queue: DispatchQueue
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private var cache = [Feed: IconImage]() // faviconURL: RSImage
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struct UserInfoKey {
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static let faviconURL = "faviconURL"
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}
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init(folder: String) {
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self.folder = folder
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self.diskCache = BinaryDiskCache(folder: folder)
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self.queue = DispatchQueue(label: "FaviconDownloader serial queue - \(folder)")
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self.homePageToFaviconURLCachePath = (folder as NSString).appendingPathComponent("HomePageToFaviconURLCache.plist")
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self.homePageURLsWithNoFaviconURLCachePath = (folder as NSString).appendingPathComponent("HomePageURLsWithNoFaviconURLCache.plist")
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loadHomePageToFaviconURLCache()
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loadHomePageURLsWithNoFaviconURLCache()
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NotificationCenter.default.addObserver(self, selector: #selector(didLoadFavicon(_:)), name: .DidLoadFavicon, object: nil)
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}
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// MARK: - API
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func resetCache() {
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cache = [Feed: IconImage]()
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}
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func favicon(for feed: Feed) -> IconImage? {
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assert(Thread.isMainThread)
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var homePageURL = feed.homePageURL
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if let faviconURL = feed.faviconURL {
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return favicon(with: faviconURL, homePageURL: homePageURL)
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}
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if homePageURL == nil {
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// Base homePageURL off feedURL if needed. Won’t always be accurate, but is good enough.
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if let feedURL = URL(string: feed.url), let scheme = feedURL.scheme, let host = feedURL.host {
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homePageURL = scheme + "://" + host + "/"
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}
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}
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if let homePageURL = homePageURL {
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return favicon(withHomePageURL: homePageURL)
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}
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return nil
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}
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func faviconAsIcon(for feed: Feed) -> IconImage? {
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if let image = cache[feed] {
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return image
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}
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if let iconImage = favicon(for: feed), let imageData = iconImage.image.dataRepresentation() {
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if let scaledImage = RSImage.scaledForIcon(imageData) {
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let scaledIconImage = IconImage(scaledImage)
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cache[feed] = scaledIconImage
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return scaledIconImage
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}
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}
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return nil
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}
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func favicon(with faviconURL: String, homePageURL: String?) -> IconImage? {
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let downloader = faviconDownloader(withURL: faviconURL, homePageURL: homePageURL)
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return downloader.iconImage
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}
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func favicon(withHomePageURL homePageURL: String) -> IconImage? {
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let url = homePageURL.normalizedURL
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if let url = URL(string: homePageURL) {
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if url.host == "nnw.ranchero.com" || url.host == "netnewswire.blog" {
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return IconImage.appIcon
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}
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}
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if homePageURLsWithNoFaviconURLCache.contains(url) {
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return nil
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}
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if let faviconURL = homePageToFaviconURLCache[url] {
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return favicon(with: faviconURL, homePageURL: url)
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}
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findFaviconURLs(with: url) { (faviconURLs) in
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if let faviconURLs = faviconURLs {
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// If the site explicitly specifies favicon.ico, it will appear twice.
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self.currentHomePageHasOnlyFaviconICO = faviconURLs.count == 1
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if let firstIconURL = faviconURLs.first {
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let _ = self.favicon(with: firstIconURL, homePageURL: url)
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self.remainingFaviconURLs[url] = faviconURLs.dropFirst()
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}
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}
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}
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return nil
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}
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// MARK: - Notifications
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@objc func didLoadFavicon(_ note: Notification) {
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guard let singleFaviconDownloader = note.object as? SingleFaviconDownloader else {
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return
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}
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guard let homePageURL = singleFaviconDownloader.homePageURL else {
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return
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}
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guard let _ = singleFaviconDownloader.iconImage else {
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if let faviconURLs = remainingFaviconURLs[homePageURL] {
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if let nextIconURL = faviconURLs.first {
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let _ = favicon(with: nextIconURL, homePageURL: singleFaviconDownloader.homePageURL)
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remainingFaviconURLs[homePageURL] = faviconURLs.dropFirst();
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} else {
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remainingFaviconURLs[homePageURL] = nil
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if currentHomePageHasOnlyFaviconICO {
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self.homePageURLsWithNoFaviconURLCache.insert(homePageURL)
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self.homePageURLsWithNoFaviconURLCacheDirty = true
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}
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}
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}
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return
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}
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remainingFaviconURLs[homePageURL] = nil
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postFaviconDidBecomeAvailableNotification(singleFaviconDownloader.faviconURL)
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}
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@objc func saveHomePageToFaviconURLCacheIfNeeded() {
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if homePageToFaviconURLCacheDirty {
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saveHomePageToFaviconURLCache()
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}
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}
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@objc func saveHomePageURLsWithNoFaviconURLCacheIfNeeded() {
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if homePageURLsWithNoFaviconURLCacheDirty {
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saveHomePageURLsWithNoFaviconURLCache()
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}
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}
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}
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private extension FaviconDownloader {
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static let localeForLowercasing = Locale(identifier: "en_US")
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func findFaviconURLs(with homePageURL: String, _ completion: @escaping ([String]?) -> Void) {
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guard let url = URL(string: homePageURL) else {
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completion(nil)
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return
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}
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FaviconURLFinder.findFaviconURLs(with: homePageURL) { (faviconURLs) in
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guard var faviconURLs = faviconURLs else {
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completion(nil)
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return
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}
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var defaultFaviconURL: String? = nil
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if let scheme = url.scheme, let host = url.host {
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defaultFaviconURL = "\(scheme)://\(host)/favicon.ico".lowercased(with: FaviconDownloader.localeForLowercasing)
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}
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if let defaultFaviconURL = defaultFaviconURL {
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faviconURLs.append(defaultFaviconURL)
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}
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completion(faviconURLs)
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}
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}
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func faviconDownloader(withURL faviconURL: String, homePageURL: String?) -> SingleFaviconDownloader {
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var firstTimeSeeingHomepageURL = false
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if let homePageURL = homePageURL, self.homePageToFaviconURLCache[homePageURL] == nil {
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self.homePageToFaviconURLCache[homePageURL] = faviconURL
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self.homePageToFaviconURLCacheDirty = true
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firstTimeSeeingHomepageURL = true
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}
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if let downloader = singleFaviconDownloaderCache[faviconURL] {
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if firstTimeSeeingHomepageURL && !downloader.downloadFaviconIfNeeded() {
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// This is to handle the scenario where we have different homepages, but the same favicon.
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// This happens for Twitter and probably other sites like Blogger. Because the favicon
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// is cached, we wouldn't send out a notification that it is now available unless we send
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// it here.
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postFaviconDidBecomeAvailableNotification(faviconURL)
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}
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return downloader
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}
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let downloader = SingleFaviconDownloader(faviconURL: faviconURL, homePageURL: homePageURL, diskCache: diskCache, queue: queue)
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singleFaviconDownloaderCache[faviconURL] = downloader
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return downloader
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}
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func postFaviconDidBecomeAvailableNotification(_ faviconURL: String) {
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DispatchQueue.main.async {
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let userInfo: [AnyHashable: Any] = [UserInfoKey.faviconURL: faviconURL]
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NotificationCenter.default.post(name: .FaviconDidBecomeAvailable, object: self, userInfo: userInfo)
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}
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}
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func loadHomePageToFaviconURLCache() {
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let url = URL(fileURLWithPath: homePageToFaviconURLCachePath)
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guard let data = try? Data(contentsOf: url) else {
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return
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}
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let decoder = PropertyListDecoder()
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homePageToFaviconURLCache = (try? decoder.decode([String: String].self, from: data)) ?? [String: String]()
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}
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func loadHomePageURLsWithNoFaviconURLCache() {
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let url = URL(fileURLWithPath: homePageURLsWithNoFaviconURLCachePath)
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guard let data = try? Data(contentsOf: url) else {
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return
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}
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let decoder = PropertyListDecoder()
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let decoded = (try? decoder.decode([String].self, from: data)) ?? [String]()
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homePageURLsWithNoFaviconURLCache = Set(decoded)
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}
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func queueSaveHomePageToFaviconURLCacheIfNeeded() {
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FaviconDownloader.saveQueue.add(self, #selector(saveHomePageToFaviconURLCacheIfNeeded))
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}
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func queueSaveHomePageURLsWithNoFaviconURLCacheIfNeeded() {
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FaviconDownloader.saveQueue.add(self, #selector(saveHomePageURLsWithNoFaviconURLCacheIfNeeded))
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}
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func saveHomePageToFaviconURLCache() {
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homePageToFaviconURLCacheDirty = false
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let encoder = PropertyListEncoder()
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encoder.outputFormat = .binary
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let url = URL(fileURLWithPath: homePageToFaviconURLCachePath)
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do {
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let data = try encoder.encode(homePageToFaviconURLCache)
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try data.write(to: url)
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} catch {
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assertionFailure(error.localizedDescription)
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}
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}
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func saveHomePageURLsWithNoFaviconURLCache() {
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homePageURLsWithNoFaviconURLCacheDirty = false
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let encoder = PropertyListEncoder()
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encoder.outputFormat = .binary
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let url = URL(fileURLWithPath: homePageURLsWithNoFaviconURLCachePath)
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do {
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let data = try encoder.encode(Array(homePageURLsWithNoFaviconURLCache))
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try data.write(to: url)
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} catch {
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assertionFailure(error.localizedDescription)
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}
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}
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}
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