Fetch bluetooth cached device name outside synchronized block.

mConnectedDevices is being accessed from both main and background thread
in BluetoothControllerImpl. This is leading to an ANR in cases where the
resource is being used in the background thread, and the main thread
is trying to update it in a synchronized block.

Bug: 323995015
Test: local CPU profiling
Flag: NONE
Change-Id: I72d1a0b61038b29a273c1b712461837e5e065e5e

2 files changed, 25 insertions, 3 deletions

diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 56576f1f0c03..407873e02aea 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -420,3 +420,12 @@ flag {
     }
 }
 
+flag {
+   name: "get_connected_device_name_unsynchronized"
+   namespace: "systemui"
+   description: "Decide whether to fetch the connected bluetooth device name outside a synchronized block."
+   bug: "323995015"
+   metadata {
+       purpose: PURPOSE_BUGFIX
+     }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/policy/BluetoothControllerImpl.java b/packages/SystemUI/src/com/android/systemui/statusbar/policy/BluetoothControllerImpl.java
index fc2f6e958b32..c089092c9b86 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/policy/BluetoothControllerImpl.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/policy/BluetoothControllerImpl.java
@@ -35,6 +35,7 @@ import com.android.settingslib.bluetooth.CachedBluetoothDevice;
 import com.android.settingslib.bluetooth.LocalBluetoothManager;
 import com.android.settingslib.bluetooth.LocalBluetoothProfile;
 import com.android.settingslib.bluetooth.LocalBluetoothProfileManager;
+import com.android.systemui.Flags;
 import com.android.systemui.bluetooth.BluetoothLogger;
 import com.android.systemui.dagger.SysUISingleton;
 import com.android.systemui.dagger.qualifiers.Background;
@@ -240,9 +241,21 @@ public class BluetoothControllerImpl implements BluetoothController, BluetoothCa
     @WorkerThread
     @Override
     public String getConnectedDeviceName() {
-        synchronized (mConnectedDevices) {
-            if (mConnectedDevices.size() == 1) {
-                return mConnectedDevices.get(0).getName();
+        if (Flags.getConnectedDeviceNameUnsynchronized()) {
+            CachedBluetoothDevice connectedDevice = null;
+            // Calling the getName() API for CachedBluetoothDevice outside the synchronized block
+            // so that the main thread is not blocked.
+            synchronized (mConnectedDevices) {
+                if (mConnectedDevices.size() == 1) {
+                    connectedDevice = mConnectedDevices.get(0);
+                }
+            }
+            return connectedDevice != null ? connectedDevice.getName() : null;
+        } else {
+            synchronized (mConnectedDevices) {
+                if (mConnectedDevices.size() == 1) {
+                    return mConnectedDevices.get(0).getName();
+                }
             }
         }
         return null;