Camera is paused occasionally when torch is enabled

https://bugs.webkit.org/show_bug.cgi?id=270831
rdar://124434403

Reviewed by Andy Estes.

We do not want to update AV capture devices before the session is running, as it may trigger interruption.
We now apply changes to device as soon as the session is running, but not before.
We apply this to torch, white balance, resolution and frame rate.

Whenever we want to update any of these, if the session is not running, we exit early and we remember to reconfigure.
When the session resumes, we check whether we need to reconfigure and do so.

* Source/WebCore/platform/mediastream/mac/AVVideoCaptureSource.h:
* Source/WebCore/platform/mediastream/mac/AVVideoCaptureSource.mm:
(WebCore::AVVideoCaptureSource::setSessionSizeFrameRateAndZoom):
(WebCore::AVVideoCaptureSource::updateWhiteBalanceMode):
(WebCore::AVVideoCaptureSource::updateTorch):
(WebCore::AVVideoCaptureSource::reconfigure):
(WebCore::AVVideoCaptureSource::captureSessionIsRunningDidChange):

Canonical link: https://commits.webkit.org/276773@main

Source/WebCore/platform/mediastream/mac/AVVideoCaptureSource.h

@@ -145,6 +145,8 @@ class AVVideoCaptureSource : public RealtimeVideoCaptureSource, private Orientat
     void updateWhiteBalanceMode();
     void updateTorch();
 
+    void reconfigureIfNeeded();
+
     void rejectPendingPhotoRequest(const String&);
     void resolvePendingPhotoRequest(Vector<uint8_t>&&, const String&);
     RetainPtr<AVCapturePhotoSettings> photoConfiguration(const PhotoSettings&);
@@ -180,6 +182,9 @@ class AVVideoCaptureSource : public RealtimeVideoCaptureSource, private Orientat
     bool m_interrupted { false };
     bool m_isRunning { false };
     bool m_hasBegunConfigurationForConstraints { false };
+    bool m_needsResolutionReconfiguration { false };
+    bool m_needsTorchReconfiguration { false };
+    bool m_needsWhiteBalanceReconfiguration { false };
 
     static constexpr Seconds verifyCaptureInterval = 30_s;
     static const uint64_t framesToDropWhenStarting = 4;

Source/WebCore/platform/mediastream/mac/AVVideoCaptureSource.mm

@@ -821,6 +821,11 @@ static bool isSameFrameRateRange(AVFrameRateRange* a, AVFrameRateRange* b)
 
     ASSERT(m_currentPreset->format());
 
+    if (!m_isRunning) {
+        m_needsResolutionReconfiguration = true;
+        return;
+    }
+
     if (!lockForConfiguration())
         return;
 
@@ -917,6 +922,11 @@ static inline IntDegrees sensorOrientation(AVCaptureVideoOrientation videoOrient
 
 void AVVideoCaptureSource::updateWhiteBalanceMode()
 {
+    if (!m_isRunning) {
+        m_needsWhiteBalanceReconfiguration = true;
+        return;
+    }
+
     beginConfigurationForConstraintsIfNeeded();
 
     if (!lockForConfiguration())
@@ -934,6 +944,11 @@ static inline IntDegrees sensorOrientation(AVCaptureVideoOrientation videoOrient
 
 void AVVideoCaptureSource::updateTorch()
 {
+    if (!m_isRunning) {
+        m_needsTorchReconfiguration = true;
+        return;
+    }
+
     beginConfigurationForConstraintsIfNeeded();
 
     if (!lockForConfiguration())
@@ -1163,6 +1178,25 @@ static inline IntDegrees sensorOrientation(AVCaptureVideoOrientation videoOrient
     resolvePendingPhotoRequest(makeVector(data), "image/jpeg"_s);
 }
 
+void AVVideoCaptureSource::reconfigureIfNeeded()
+{
+    if (!m_isRunning || (!m_needsResolutionReconfiguration && !m_needsTorchReconfiguration && !m_needsWhiteBalanceReconfiguration))
+        return;
+
+    beginConfiguration();
+
+    if (std::exchange(m_needsResolutionReconfiguration, false))
+        setSessionSizeFrameRateAndZoom();
+
+    if (std::exchange(m_needsTorchReconfiguration, false))
+        updateTorch();
+
+    if (std::exchange(m_needsWhiteBalanceReconfiguration, false))
+        updateWhiteBalanceMode();
+
+    commitConfiguration();
+}
+
 void AVVideoCaptureSource::captureSessionIsRunningDidChange(bool state)
 {
     scheduleDeferredTask([this, logIdentifier = LOGIDENTIFIER, state] {
@@ -1172,6 +1206,8 @@ static inline IntDegrees sensorOrientation(AVCaptureVideoOrientation videoOrient
 
         m_isRunning = state;
 
+        reconfigureIfNeeded();
+
         updateVerifyCapturingTimer();
         notifyMutedChange(!m_isRunning);
     });