audio/internal/readerdriver: Implement for iOS

Updates #1549

audio/internal/readerdriver/driver_darwin.go

@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !ios
-
 package readerdriver
 
 // #cgo LDFLAGS: -framework AudioToolbox
@@ -30,6 +28,7 @@ import (
 	"io"
 	"runtime"
 	"sync"
+	"time"
 	"unsafe"
 )
 
@@ -366,10 +365,19 @@ func (p *playerImpl) Play() {
 		return
 	}
 
-	if osstatus := C.AudioQueueStart(p.audioQueue, nil); osstatus != C.noErr {
-		p.setErrorImpl(fmt.Errorf("readerdriver: AudioQueueStart failed: %d", osstatus))
-		return
+	for {
+		if osstatus := C.AudioQueueStart(p.audioQueue, nil); osstatus != C.noErr {
+			// AudioQueueStart might fail just after recovering from Siri.
+			if osstatus == C.AVAudioSessionErrorCodeSiriIsRecording {
+				time.Sleep(10 * time.Millisecond)
+				continue
+			}
+			p.setErrorImpl(fmt.Errorf("readerdriver: AudioQueueStart failed: %d", osstatus))
+			return
+		}
+		break
 	}
+
 	p.state = playerPlay
 	p.cond.Signal()
 

audio/internal/readerdriver/driver_default.go

@@ -13,8 +13,8 @@
 // limitations under the License.
 
 // +build !android
+// +build !darwin
 // +build !js
-// +build darwin,ios !darwin
 
 package readerdriver
 

audio/internal/readerdriver/driver_ios.m

@@ -0,0 +1,22 @@
+// Copyright 2021 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build ios
+
+void ebiten_readerdriver_setNotificationHandler() {
+  // AVAudioSessionInterruptionNotification is not reliable on iOS. Rely on
+  // applicationWillResignActive and applicationDidBecomeActive instead. See
+  // https://stackoverflow.com/questions/24404463/ios-siri-not-available-does-not-return-avaudiosessioninterruptionoptionshouldre
+  return;
+}