From c1f083d143a32da49ec3c65a9cafb5ef30fe3855 Mon Sep 17 00:00:00 2001
From: JT Teh <jtteh@webrtc.org>
Date: Wed, 25 Apr 2018 09:19:35 -0700
Subject: [PATCH] Add notifiers for when the audio session will be
 activated/deactivated, did activate/deactivate and failed to
 activate/deactivate.
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Bug: webrtc:9191
Change-Id: I68a71701dd4c3660331080495b5be4408493aa86
Reviewed-on: https://webrtc-review.googlesource.com/72262
Commit-Queue: JT Teh <jtteh@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23028}
---
 .../Classes/Audio/RTCAudioSession.mm          | 30 +++++++++++++++++++
 .../Headers/WebRTC/RTCAudioSession.h          | 14 +++++++++
 2 files changed, 44 insertions(+)

diff --git a/sdk/objc/Framework/Classes/Audio/RTCAudioSession.mm b/sdk/objc/Framework/Classes/Audio/RTCAudioSession.mm
index 67a70da800..69cfa22aa8 100644
--- a/sdk/objc/Framework/Classes/Audio/RTCAudioSession.mm
+++ b/sdk/objc/Framework/Classes/Audio/RTCAudioSession.mm
@@ -335,6 +335,7 @@ NSString * const kRTCAudioSessionOutputVolumeSelector = @"outputVolume";
   if (!active && activationCount == 0) {
     RTCLogWarning(@"Attempting to deactivate without prior activation.");
   }
+  [self notifyWillSetActive:active];
   BOOL success = YES;
   BOOL isActive = self.isActive;
   // Keep a local error so we can log it.
@@ -365,9 +366,11 @@ NSString * const kRTCAudioSessionOutputVolumeSelector = @"outputVolume";
     if (active) {
       [self incrementActivationCount];
     }
+    [self notifyDidSetActive:active];
   } else {
     RTCLogError(@"Failed to setActive:%d. Error: %@",
                 active, error.localizedDescription);
+    [self notifyFailedToSetActive:active error:error];
   }
   // Decrement activation count on deactivation whether or not it succeeded.
   if (!active) {
@@ -931,4 +934,31 @@ NSString * const kRTCAudioSessionOutputVolumeSelector = @"outputVolume";
   }
 }
 
+- (void)notifyWillSetActive:(BOOL)active {
+  for (id delegate : self.delegates) {
+    SEL sel = @selector(audioSession:willSetActive:);
+    if ([delegate respondsToSelector:sel]) {
+      [delegate audioSession:self willSetActive:active];
+    }
+  }
+}
+
+- (void)notifyDidSetActive:(BOOL)active {
+  for (id delegate : self.delegates) {
+    SEL sel = @selector(audioSession:didSetActive:);
+    if ([delegate respondsToSelector:sel]) {
+      [delegate audioSession:self didSetActive:active];
+    }
+  }
+}
+
+- (void)notifyFailedToSetActive:(BOOL)active error:(NSError *)error {
+  for (id delegate : self.delegates) {
+    SEL sel = @selector(audioSession:failedToSetActive:error:);
+    if ([delegate respondsToSelector:sel]) {
+      [delegate audioSession:self failedToSetActive:active error:error];
+    }
+  }
+}
+
 @end
diff --git a/sdk/objc/Framework/Headers/WebRTC/RTCAudioSession.h b/sdk/objc/Framework/Headers/WebRTC/RTCAudioSession.h
index 354634ec39..6c4c96ab05 100644
--- a/sdk/objc/Framework/Headers/WebRTC/RTCAudioSession.h
+++ b/sdk/objc/Framework/Headers/WebRTC/RTCAudioSession.h
@@ -84,6 +84,20 @@ RTC_EXPORT
 - (void)audioSession:(RTCAudioSession *)audioSession
     didDetectPlayoutGlitch:(int64_t)totalNumberOfGlitches;
 
+/** Called when the audio session is about to change the active state.
+ */
+- (void)audioSession:(RTCAudioSession *)audioSession willSetActive:(BOOL)active;
+
+/** Called after the audio session sucessfully changed the active state.
+ */
+- (void)audioSession:(RTCAudioSession *)audioSession didSetActive:(BOOL)active;
+
+/** Called after the audio session failed to change the active state.
+ */
+- (void)audioSession:(RTCAudioSession *)audioSession
+    failedToSetActive:(BOOL)active
+                error:(NSError *)error;
+
 @end
 
 /** This is a protocol used to inform RTCAudioSession when the audio session