sokol_audio.h: fix ARC vs non-ARC on iOS

1 files changed, 36 insertions, 28 deletions

diff --git a/sokol_audio.h b/sokol_audio.h
index f85f3d67..83d27e1d 100644
--- a/sokol_audio.h
+++ b/sokol_audio.h
@@ -41,7 +41,8 @@
 
     - Windows: WASAPI
     - Linux: ALSA (link with asound)
-    - macOS/iOS: CoreAudio (link with AudioToolbox)
+    - macOS: CoreAudio (link with AudioToolbox)
+    - iOS: CoreAudio+AVAudioSession (link with AudioToolbox and AVFramework)
     - emscripten: WebAudio with ScriptProcessorNode
     - Android: OpenSLES (link with OpenSLES)
 
@@ -309,6 +310,7 @@
     The CoreAudio backend is selected on macOS and iOS (__APPLE__ is defined).
     Since the CoreAudio API is implemented in C (not Objective-C) on macOS the
     implementation part of Sokol Audio can be included into a C source file.
+
     However on iOS, Sokol Audio must be compiled as Objective-C due to it's
     reliance on the AVAudioSession object.
 
@@ -513,9 +515,14 @@ inline void saudio_setup(const saudio_desc& desc) { return saudio_setup(&desc);
 #elif defined(__APPLE__)
     #include <TargetConditionals.h>
     #include <AudioToolbox/AudioToolbox.h>
-#if TARGET_OS_IOS
-    #include <AVFoundation/AVFoundation.h>
-#endif
+    #if TARGET_OS_IOS
+        #if !defined(__cplusplus)
+            #if __has_feature(objc_arc) && !__has_feature(objc_arc_fields)
+                #error "sokol_audio.h on iOS requires __has_feature(objc_arc_field) if ARC is enabled (use a more recent compiler version)"
+            #endif
+        #endif
+        #include <AVFoundation/AVFoundation.h>
+    #endif
 #elif (defined(__linux__) || defined(__unix__)) && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__)
     #define ALSA_PCM_NEW_HW_PARAMS_API
     #include <alsa/asoundlib.h>
@@ -603,9 +610,9 @@ typedef struct {
 
 typedef struct {
     AudioQueueRef ca_audio_queue;
-#if TARGET_OS_IOS
-    void* ca_interruption_handler;
-#endif
+    #if TARGET_OS_IOS
+    id ca_interruption_handler;
+    #endif
 } _saudio_backend_t;
 
 /*=== ALSA BACKEND DECLARATIONS ==============================================*/
@@ -982,31 +989,33 @@ _SOKOL_PRIVATE void _saudio_backend_shutdown(void) { };
 #elif defined(__APPLE__)
 
 #if TARGET_OS_IOS
-@interface _saudio_interruption_handler:NSObject {
-}
+#if __has_feature(objc_arc)
+#define _SAUDIO_OBJC_RELEASE(obj) { obj = nil; }
+#else
+#define _SAUDIO_OBJC_RELEASE(obj) { [obj release]; obj = nil; }
+#endif
+
+@interface _saudio_interruption_handler : NSObject { }
 @end
 
 @implementation _saudio_interruption_handler
--(id)init
-{
+-(id)init {
     self = [super init];
     AVAudioSession* session = [AVAudioSession sharedInstance];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handle_interruption:) name:AVAudioSessionInterruptionNotification object:session];
     return self;
 }
 
--(void)dealloc
-{
+-(void)dealloc {
     [self remove_handler];
+    [super dealloc];
 }
 
--(void)remove_handler
-{
+-(void)remove_handler {
     [[NSNotificationCenter defaultCenter] removeObserver:self name:@"AVAudioSessionInterruptionNotification" object:nil];
 }
 
--(void)handle_interruption:(NSNotification*)notification
-{
+-(void)handle_interruption:(NSNotification*)notification {
     AVAudioSession* session = [AVAudioSession sharedInstance];
     SOKOL_ASSERT(session);
     NSDictionary* dict = notification.userInfo;
@@ -1050,16 +1059,17 @@ _SOKOL_PRIVATE void _saudio_coreaudio_callback(void* user_data, AudioQueueRef qu
 _SOKOL_PRIVATE bool _saudio_backend_init(void) {
     SOKOL_ASSERT(0 == _saudio.backend.ca_audio_queue);
 
-#if TARGET_OS_IOS
+    #if TARGET_OS_IOS
     /* activate audio session */
     AVAudioSession* session = [AVAudioSession sharedInstance];
-    SOKOL_ASSERT(session);
+    SOKOL_ASSERT(session != nil);
     [session setCategory: AVAudioSessionCategoryPlayback withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker error:nil];
     [session setActive:true error:nil];
 
     /* create interruption handler */
-    _saudio.backend.ca_interruption_handler = (__bridge_retained void*)[[_saudio_interruption_handler alloc] init];
-#endif
+    _saudio.backend.ca_interruption_handler = [[_saudio_interruption_handler alloc] init];
+    #endif
+
     /* create an audio queue with fp32 samples */
     AudioStreamBasicDescription fmt;
     memset(&fmt, 0, sizeof(fmt));
@@ -1099,19 +1109,17 @@ _SOKOL_PRIVATE void _saudio_backend_shutdown(void) {
     AudioQueueStop(_saudio.backend.ca_audio_queue, true);
     AudioQueueDispose(_saudio.backend.ca_audio_queue, false);
     _saudio.backend.ca_audio_queue = NULL;
-#if TARGET_OS_IOS
+    #if TARGET_OS_IOS
     /* remove interruption handler */
-    if (_saudio.backend.ca_interruption_handler != NULL) {
-        _saudio_interruption_handler* interruption_handler = (__bridge_transfer _saudio_interruption_handler*)_saudio.backend.ca_interruption_handler;
-        [interruption_handler remove_handler];
-        _saudio.backend.ca_interruption_handler = NULL;
+    if (_saudio.backend.ca_interruption_handler != nil) {
+        [_saudio.backend.ca_interruption_handler remove_handler];
+        _SAUDIO_OBJC_RELEASE(_saudio.backend.ca_interruption_handler);
     }
-
     /* deactivate audio session */
     AVAudioSession* session = [AVAudioSession sharedInstance];
     SOKOL_ASSERT(session);
     [session setActive:false error:nil];;
-#endif
+    #endif
 }
 
 /*=== ALSA BACKEND IMPLEMENTATION ============================================*/