Fix asynchronoucity with the TTS

Sources/Navigator/EPUB/EPUBNavigatorViewController.swift

@@ -377,7 +377,6 @@ open class EPUBNavigatorViewController: UIViewController,
 
     /// Intercepts tap gesture when the web views are not loaded.
     @objc private func didTapBackground(_ gesture: UITapGestureRecognizer) {
-        guard case .loading = state else { return }
         didTap(at: gesture.location(in: view))
     }
 

Sources/Navigator/TTS/AVTTSEngine.swift

@@ -64,6 +64,7 @@ public class AVTTSEngine: NSObject, TTSEngine, AVSpeechSynthesizerDelegate, Logg
             .map { TTSVoice(voice: $0) }
     }
 
+    @MainActor
     public func speak(
         _ utterance: TTSUtterance,
         onSpeakRange: @escaping (Range<String.Index>) -> Void

Sources/Navigator/TTS/PublicationSpeechSynthesizer.swift

@@ -10,9 +10,11 @@ import ReadiumShared
 
 public protocol PublicationSpeechSynthesizerDelegate: AnyObject {
     /// Called when the synthesizer's state is updated.
+    @MainActor
     func publicationSpeechSynthesizer(_ synthesizer: PublicationSpeechSynthesizer, stateDidChange state: PublicationSpeechSynthesizer.State)
 
     /// Called when an `error` occurs while speaking `utterance`.
+    @MainActor
     func publicationSpeechSynthesizer(_ synthesizer: PublicationSpeechSynthesizer, utterance: PublicationSpeechSynthesizer.Utterance, didFailWithError error: PublicationSpeechSynthesizer.Error)
 }
 
@@ -89,7 +91,9 @@ public class PublicationSpeechSynthesizer: Loggable {
                 AudioSession.shared.user(audioSessionUser, didChangePlaying: state.isPlaying)
             }
 
-            delegate?.publicationSpeechSynthesizer(self, stateDidChange: state)
+            Task {
+                await delegate?.publicationSpeechSynthesizer(self, stateDidChange: state)
+            }
         }
     }
 
@@ -296,7 +300,7 @@ public class PublicationSpeechSynthesizer: Loggable {
             await playNextUtterance(.forward)
         case let .failure(error):
             state = .paused(utterance)
-            delegate?.publicationSpeechSynthesizer(self, utterance: utterance, didFailWithError: .engine(error))
+            await delegate?.publicationSpeechSynthesizer(self, utterance: utterance, didFailWithError: .engine(error))
         }
     }
 

Sources/Shared/Toolkit/Format/Sniffers/EPUBFormatSniffer.swift

@@ -38,7 +38,7 @@ public struct EPUBFormatSniffer: FormatSniffer {
 
         return await resource.readAsString()
             .flatMap { mimetype in
-                if MediaType.epub.matches(MediaType(mimetype)) {
+                if MediaType.epub.matches(MediaType(mimetype.trimmingCharacters(in: .whitespacesAndNewlines))) {
                     var format = format
                     format.addSpecifications(.epub)
                     if format.conformsTo(.zip) {

Sources/Shared/Toolkit/Media/AudioSession.swift

@@ -28,6 +28,7 @@ public extension AudioSessionUser {
 }
 
 /// Manages an activated `AVAudioSession`.
+@MainActor
 public final class AudioSession: Loggable {
     public struct Configuration: Equatable {
         let category: AVAudioSession.Category
@@ -49,41 +50,67 @@ public final class AudioSession: Loggable {
     }
 
     /// Shared `AudioSession` for this app.
-    public static let shared = AudioSession()
+    public nonisolated static let shared = AudioSession()
 
-    private init() {
-        observeAppStateChanges()
+    private nonisolated init() {
+        Task {
+            await observeAppStateChanges()
+        }
     }
 
     deinit {
         NotificationCenter.default.removeObserver(self)
     }
 
+    struct User {
+        let id: ObjectIdentifier
+        private(set) weak var user: AudioSessionUser?
+
+        init(_ user: AudioSessionUser) {
+            id = ObjectIdentifier(user)
+            self.user = user
+        }
+    }
+
     /// Current user of the `AudioSession`.
-    private weak var user: AudioSessionUser?
+    private var user: User?
 
     /// Starts a new audio session with the given `user`.
-    public func start(with user: AudioSessionUser, isPlaying: Bool) {
-        guard self.user !== user else {
+    public nonisolated func start(with user: AudioSessionUser, isPlaying: Bool) {
+        Task {
+            await start(with: user, isPlaying: isPlaying)
+        }
+    }
+
+    private func start(with user: AudioSessionUser, isPlaying: Bool) async {
+        let id = ObjectIdentifier(user)
+        guard self.user?.id != id else {
             return
         }
 
         if let oldUser = self.user {
-            end(for: oldUser)
+            end(forUserID: oldUser.id)
         }
-        self.user = user
+        self.user = User(user)
         self.isPlaying = false
 
         startSession(with: user.audioConfiguration)
     }
 
     /// Ends the current audio session.
-    public func end(for user: AudioSessionUser) {
-        guard self.user === user || self.user == nil else {
+    public nonisolated func end(for user: AudioSessionUser) {
+        let id = ObjectIdentifier(user)
+        Task {
+            await end(forUserID: id)
+        }
+    }
+
+    private func end(forUserID id: ObjectIdentifier) {
+        guard user?.id == id else {
             return
         }
 
-        self.user = nil
+        user = nil
         isPlaying = false
 
         endSession()
@@ -92,8 +119,15 @@ public final class AudioSession: Loggable {
     /// Indicates whether the `user` is playing.
     private var isPlaying: Bool = false
 
-    public func user(_ user: AudioSessionUser, didChangePlaying isPlaying: Bool) {
-        guard self.user === user, self.isPlaying != isPlaying else {
+    public nonisolated func user(_ user: AudioSessionUser, didChangePlaying isPlaying: Bool) {
+        Task {
+            await self.user(user, didChangePlaying: isPlaying)
+        }
+    }
+
+    private func user(_ user: AudioSessionUser, didChangePlaying isPlaying: Bool) async {
+        let id = ObjectIdentifier(user)
+        guard self.user?.id == id, self.isPlaying != isPlaying else {
             return
         }
 
@@ -131,6 +165,7 @@ public final class AudioSession: Loggable {
         do {
             try audioSession.setCategory(config.category, mode: config.mode, policy: config.routeSharingPolicy, options: config.options)
             try audioSession.setActive(true)
+            log(.info, "Started audio session with category: \(config.category), mode: \(config.mode), policy: \(config.routeSharingPolicy), options: \(config.options)")
         } catch {
             log(.error, "Failed to start the audio session: \(error)")
         }
@@ -154,6 +189,7 @@ public final class AudioSession: Loggable {
         do {
             AVAudioSession.sharedInstance()
             try AVAudioSession.sharedInstance().setActive(false)
+            log(.info, "Ended audio session")
         } catch {
             log(.error, "Failed to end the audio session: \(error)")
         }
@@ -168,7 +204,7 @@ public final class AudioSession: Loggable {
     /// The observer of audio session interruption notifications.
     private var interruptionObserver: Any?
 
-    private func handleAudioSessionInterruption(notification: Notification) {
+    private nonisolated func handleAudioSessionInterruption(notification: Notification) {
         guard let userInfo = notification.userInfo,
               let rawInterruptionType = userInfo[AVAudioSessionInterruptionTypeKey] as? UInt,
               let interruptionType = AVAudioSession.InterruptionType(rawValue: rawInterruptionType)
@@ -180,7 +216,13 @@ public final class AudioSession: Loggable {
             .map(AVAudioSession.InterruptionOptions.init(rawValue:))
             ?? []
 
-        switch interruptionType {
+        Task {
+            await handleAudioSessionInterruption(type: interruptionType, options: options)
+        }
+    }
+
+    private func handleAudioSessionInterruption(type: AVAudioSession.InterruptionType, options: AVAudioSession.InterruptionOptions) {
+        switch type {
         case .began:
             isInterrupted = true
 
@@ -190,7 +232,7 @@ public final class AudioSession: Loggable {
             // When an interruption ends, determine whether playback should resume automatically,
             // and reactivate the audio session if necessary.
             do {
-                if let user = user {
+                if let user = user?.user {
                     try AVAudioSession.sharedInstance().setActive(true)
 
                     if options.contains(.shouldResume) {

TestApp/Sources/Library/LibraryError.swift

@@ -12,6 +12,7 @@ enum LibraryError: LocalizedError {
     case bookNotFound
     case bookDeletionFailed(Error?)
     case importFailed(Error)
+    case publicationIsRestricted(Error)
     case openFailed(Error)
     case downloadFailed(Error?)
     case cancelled

TestApp/Sources/Library/LibraryService.swift

@@ -68,11 +68,10 @@ final class LibraryService: Loggable {
     }
 
     /// Checks if the publication is not still locked by a DRM.
-    // FIXME: Better error
     private func checkIsReadable(publication: Publication) throws {
         guard !publication.isRestricted else {
             if let error = publication.protectionError {
-                throw LibraryError.openFailed(error)
+                throw LibraryError.publicationIsRestricted(error)
             } else {
                 throw LibraryError.cancelled
             }

TestApp/Sources/Reader/Common/VisualReaderViewController.swift

@@ -83,6 +83,7 @@ class VisualReaderViewController<N: UIViewController & Navigator>: ReaderViewCon
 
         if let state = ttsViewModel?.$state, let controls = ttsControlsViewController {
             controls.view.backgroundColor = .clear
+            controls.view.isHidden = true
 
             addChild(controls)
             controls.view.translatesAutoresizingMaskIntoConstraints = false
@@ -94,6 +95,7 @@ class VisualReaderViewController<N: UIViewController & Navigator>: ReaderViewCon
             controls.didMove(toParent: self)
 
             state
+                .receive(on: DispatchQueue.main)
                 .sink { state in
                     controls.view.isHidden = !state.showControls
                 }