work around swift4.2 AudioSession API bug

Signal.xcodeproj/project.pbxproj

@@ -488,6 +488,7 @@
 		4C4BC6C32102D697004040C9 /* ContactDiscoveryOperationTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C4BC6C22102D697004040C9 /* ContactDiscoveryOperationTest.swift */; };
 		4C5250D221E7BD7D00CE3D95 /* PhoneNumberValidator.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C5250D121E7BD7D00CE3D95 /* PhoneNumberValidator.swift */; };
 		4C5250D421E7C51900CE3D95 /* PhoneNumberValidatorTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C5250D321E7C51900CE3D95 /* PhoneNumberValidatorTest.swift */; };
+		4C586926224FAB83003FD070 /* AVAudioSession+OWS.m in Sources */ = {isa = PBXBuildFile; fileRef = 4C586925224FAB83003FD070 /* AVAudioSession+OWS.m */; };
 		4C618199219DF03A009BD6B5 /* OWSButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C618198219DF03A009BD6B5 /* OWSButton.swift */; };
 		4C61819F219E1796009BD6B5 /* typing-animation-dark.gif in Resources */ = {isa = PBXBuildFile; fileRef = 4C61819E219E1795009BD6B5 /* typing-animation-dark.gif */; };
 		4C63CC00210A620B003AE45C /* SignalTSan.supp in Resources */ = {isa = PBXBuildFile; fileRef = 4C63CBFF210A620B003AE45C /* SignalTSan.supp */; };
@@ -1239,6 +1240,8 @@
 		4C4BC6C22102D697004040C9 /* ContactDiscoveryOperationTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = ContactDiscoveryOperationTest.swift; path = contact/ContactDiscoveryOperationTest.swift; sourceTree = "<group>"; };
 		4C5250D121E7BD7D00CE3D95 /* PhoneNumberValidator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PhoneNumberValidator.swift; sourceTree = "<group>"; };
 		4C5250D321E7C51900CE3D95 /* PhoneNumberValidatorTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PhoneNumberValidatorTest.swift; sourceTree = "<group>"; };
+		4C586924224FAB83003FD070 /* AVAudioSession+OWS.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = "AVAudioSession+OWS.h"; path = "util/UI Categories/AVAudioSession+OWS.h"; sourceTree = "<group>"; };
+		4C586925224FAB83003FD070 /* AVAudioSession+OWS.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = "AVAudioSession+OWS.m"; path = "util/UI Categories/AVAudioSession+OWS.m"; sourceTree = "<group>"; };
 		4C618198219DF03A009BD6B5 /* OWSButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OWSButton.swift; sourceTree = "<group>"; };
 		4C61819E219E1795009BD6B5 /* typing-animation-dark.gif */ = {isa = PBXFileReference; lastKnownFileType = image.gif; path = "typing-animation-dark.gif"; sourceTree = "<group>"; };
 		4C63CBFF210A620B003AE45C /* SignalTSan.supp */ = {isa = PBXFileReference; lastKnownFileType = text; path = SignalTSan.supp; sourceTree = "<group>"; };
@@ -2692,6 +2695,8 @@
 				EF764C331DB67CC5000D9A87 /* UIViewController+Permissions.h */,
 				EF764C341DB67CC5000D9A87 /* UIViewController+Permissions.m */,
 				45B5360D206DD8BB00D61655 /* UIResponder+OWS.swift */,
+				4C586924224FAB83003FD070 /* AVAudioSession+OWS.h */,
+				4C586925224FAB83003FD070 /* AVAudioSession+OWS.m */,
 			);
 			name = "UI Categories";
 			path = ..;
@@ -3661,6 +3666,7 @@
 				4517642B1DE939FD00EDB8B9 /* ContactCell.swift in Sources */,
 				34EA69402194933900702471 /* MediaDownloadView.swift in Sources */,
 				340FC8AB204DAC8D007AEB0F /* DomainFrontingCountryViewController.m in Sources */,
+				4C586926224FAB83003FD070 /* AVAudioSession+OWS.m in Sources */,
 				3496744D2076768700080B5F /* OWSMessageBubbleView.m in Sources */,
 				34B3F8751E8DF1700035BE1A /* CallViewController.swift in Sources */,
 				4C4AE6A1224AF35700D4AF6F /* SendMediaNavigationController.swift in Sources */,

Signal/src/Signal-Bridging-Header.h

@@ -6,6 +6,7 @@
 #import <UIKit/UIKit.h>
 
 // Separate iOS Frameworks from other imports.
+#import "AVAudioSession+OWS.h"
 #import "AppSettingsViewController.h"
 #import "AttachmentUploadView.h"
 #import "AvatarViewHelper.h"

Signal/src/call/CallAudioService.swift

@@ -534,8 +534,7 @@ protocol CallAudioServiceDelegate: class {
                 if oldOptions != options {
                     Logger.debug("audio session changed options: \(oldOptions) -> \(options) ")
                 }
-                try avAudioSession.setCategory(category, with: options)
-
+                try avAudioSession.ows_setCategory(category, with: options)
             }
         } catch {
             let message = "failed to set category: \(category) mode: \(String(describing: mode)), options: \(options) with error: \(error)"

Signal/src/util/UI Categories/AVAudioSession+OWS.h

@@ -0,0 +1,22 @@
+//
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
+//
+
+#import <AVFoundation/AVAudioSession.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface AVAudioSession (OWS)
+
+// #RADAR 45397675 http://www.openradar.me/45397675
+//
+// A bug in Swift 4.2+ made `AVAudioSession#setCategory:categorywithOptions:error` not accessible
+// to Swift.
+//
+// It's still available via ObjC, so we have an objc-category method which we can call from Swift
+// which just calls the original `AVAudioSession#setCategory:categorywithOptions:error` method.
+- (BOOL)ows_setCategory:(AVAudioSessionCategory)category withOptions:(AVAudioSessionCategoryOptions)options error:(NSError **)outError API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);
+
+@end
+
+NS_ASSUME_NONNULL_END

Signal/src/util/UI Categories/AVAudioSession+OWS.m

@@ -0,0 +1,15 @@
+//
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
+//
+
+#import "AVAudioSession+OWS.h"
+
+@implementation AVAudioSession(OWS)
+
+
+- (BOOL)ows_setCategory:(AVAudioSessionCategory)category withOptions:(AVAudioSessionCategoryOptions)options error:(NSError **)outError API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos)
+{
+    return [self setCategory:category withOptions:options error:outError];
+}
+
+@end