117 lines
4.6 KiB
Swift
117 lines
4.6 KiB
Swift
//
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// Copyright 2020 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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//
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import SignalServiceKit
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extension Emoji {
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private static let availableCache = AtomicDictionary<Emoji, Bool>(lock: .sharedGlobal)
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private static let iosVersionKey = "iosVersion"
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private static let cacheUrl = OWSFileSystem.appSharedDataDirectoryURL()
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.appendingPathComponent("Library")
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.appendingPathComponent("Caches")
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.appendingPathComponent("emoji.plist")
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static func warmAvailableCache() {
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owsAssertDebug(!Thread.isMainThread)
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guard CurrentAppContext().hasUI else { return }
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var availableCache = [Emoji: Bool]()
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var uncachedEmoji = [Emoji]()
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let iosVersion = AppVersionImpl.shared.iosVersionString
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// Use an NSMutableDictionary for built-in plist serialization and heterogeneous values.
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var availableMap = NSMutableDictionary()
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do {
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availableMap = try NSMutableDictionary(contentsOf: Self.cacheUrl, error: ())
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} catch {
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Logger.info("Re-building emoji availability cache. Cache could not be loaded. \(error)")
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uncachedEmoji = Emoji.allCases
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}
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let lastIosVersion = availableMap[iosVersionKey] as? String
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if lastIosVersion == iosVersion {
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for emoji in Emoji.allCases {
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if let available = availableMap[emoji.rawValue] as? Bool {
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availableCache[emoji] = available
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} else {
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Logger.warn("Emoji unexpectedly missing from cache: \(emoji).")
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uncachedEmoji.append(emoji)
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}
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}
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} else if uncachedEmoji.isEmpty {
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Logger.info("Re-building emoji availability cache. iOS version upgraded from \(lastIosVersion ?? "(none)") -> \(iosVersion)")
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uncachedEmoji = Emoji.allCases
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}
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if !uncachedEmoji.isEmpty {
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Logger.info("Checking emoji availability for \(uncachedEmoji.count) uncached emoji")
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uncachedEmoji.forEach {
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let available = isEmojiAvailable($0)
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availableMap[$0.rawValue] = available
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availableCache[$0] = available
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}
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availableMap[iosVersionKey] = iosVersion
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do {
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// Use FileManager.createDirectory directly because OWSFileSystem.ensureDirectoryExists
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// can modify the protection, and this is a system-managed directory.
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try FileManager.default.createDirectory(at: Self.cacheUrl.deletingLastPathComponent(),
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withIntermediateDirectories: true)
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try availableMap.write(to: Self.cacheUrl)
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} catch {
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Logger.warn("Failed to save emoji availability cache; it will be recomputed next time! \(error)")
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}
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}
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Self.availableCache.set(availableCache)
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}
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private static func isEmojiAvailable(_ emoji: Emoji) -> Bool {
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owsAssertDebug(CurrentAppContext().hasUI)
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return emoji.rawValue.isUnicodeStringAvailable
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}
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/// Indicates whether the given emoji is available on this iOS
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/// version. We cache the availability in memory.
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var available: Bool {
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owsAssertDebug(CurrentAppContext().hasUI)
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guard let available = Self.availableCache[self] else {
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let available = Self.isEmojiAvailable(self)
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Self.availableCache[self] = available
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return available
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}
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return available
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}
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}
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private extension String {
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/// A known undefined unicode character for comparison
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private static let unknownUnicodeStringPng = "\u{1fff}".unicodeStringPngRepresentation
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// Based on https://stackoverflow.com/a/41393387
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// Check if an emoji is available on the current iOS version
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// by verifying its image is different than the "unknown"
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// reference image
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var isUnicodeStringAvailable: Bool {
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guard isSingleEmoji else { return false }
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return String.unknownUnicodeStringPng != unicodeStringPngRepresentation
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}
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var unicodeStringPngRepresentation: Data? {
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let attributes = [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 8)]
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let size = (self as NSString).size(withAttributes: attributes)
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UIGraphicsBeginImageContext(size)
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defer { UIGraphicsEndImageContext() }
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(self as NSString).draw(at: CGPoint(x: 0, y: 0), withAttributes: attributes)
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guard let unicodeImage = UIGraphicsGetImageFromCurrentImageContext() else { return nil }
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return unicodeImage.pngData()
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}
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}
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