From 77535ce22a71b04fd45f526e8c03976e42761ec2 Mon Sep 17 00:00:00 2001
From: jackqdyulei <jackqdyulei@google.com>
Date: Wed, 13 Feb 2019 13:17:38 -0800
Subject: [PATCH] Fix deadlock in LocalBluetoothManager

Following deadlock exist in previous code:
1. Main thread
Device.refresh()->Device.dispatchCallback()->Lock callback->(handle
callback in systemui)->DeviceManager.getDevicesCopy()-> try lock
deviceManager
2. Bg thread
DeviceManager.onUuidChange()->Lock
deviceManager->Device.refresh()->Device.dispatchCallback()-> try lock
callback

This CL remove sychnorized method in DeviceManager to unblock this
deadlock. Since UuidChange can only happen in bg thread, we don't need
this extra lock in DeviceManager.

Fixes: 112483982
Test: Manual
Change-Id: I1a8bb130cfff40358783f5f5da7e50e5f0a42e20
---
 .../bluetooth/BluetoothEventManager.java          | 10 ++++++++--
 .../bluetooth/CachedBluetoothDeviceManager.java   | 14 --------------
 .../CachedBluetoothDeviceManagerTest.java         | 15 ---------------
 3 files changed, 8 insertions(+), 31 deletions(-)

diff --git a/packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothEventManager.java b/packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothEventManager.java
index 4f18d450462d5..402ce90d6ec56 100644
--- a/packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothEventManager.java
+++ b/packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothEventManager.java
@@ -420,14 +420,20 @@ public class BluetoothEventManager {
     private class ClassChangedHandler implements Handler {
         public void onReceive(Context context, Intent intent,
                 BluetoothDevice device) {
-            mDeviceManager.onBtClassChanged(device);
+            CachedBluetoothDevice cachedDevice = mDeviceManager.findDevice(device);
+            if (cachedDevice != null) {
+                cachedDevice.refresh();
+            }
         }
     }
 
     private class UuidChangedHandler implements Handler {
         public void onReceive(Context context, Intent intent,
                 BluetoothDevice device) {
-            mDeviceManager.onUuidChanged(device);
+            CachedBluetoothDevice cachedDevice = mDeviceManager.findDevice(device);
+            if (cachedDevice != null) {
+                cachedDevice.onUuidChanged();
+            }
         }
     }
 
diff --git a/packages/SettingsLib/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManager.java b/packages/SettingsLib/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManager.java
index 5b4a8b4f259e0..33e7540448734 100644
--- a/packages/SettingsLib/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManager.java
+++ b/packages/SettingsLib/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManager.java
@@ -206,20 +206,6 @@ public class CachedBluetoothDeviceManager {
         }
     }
 
-    public synchronized void onBtClassChanged(BluetoothDevice device) {
-        CachedBluetoothDevice cachedDevice = findDevice(device);
-        if (cachedDevice != null) {
-            cachedDevice.dispatchAttributesChanged();
-        }
-    }
-
-    public synchronized void onUuidChanged(BluetoothDevice device) {
-        CachedBluetoothDevice cachedDevice = findDevice(device);
-        if (cachedDevice != null) {
-            cachedDevice.onUuidChanged();
-        }
-    }
-
     public synchronized void onBluetoothStateChanged(int bluetoothState) {
         // When Bluetooth is turning off, we need to clear the non-bonded devices
         // Otherwise, they end up showing up on the next BT enable
diff --git a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManagerTest.java b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManagerTest.java
index 43b289464e1d0..dc47de8546dbe 100644
--- a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManagerTest.java
+++ b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/bluetooth/CachedBluetoothDeviceManagerTest.java
@@ -368,21 +368,6 @@ public class CachedBluetoothDeviceManagerTest {
         verify(mHearingAidDeviceManager).updateHearingAidsDevices();
     }
 
-    /**
-     * Test to verify onBtClassChanged().
-     */
-    @Test
-    public void onBtClassChanged_validBtClass_classChanged() {
-        CachedBluetoothDevice cachedDevice1 = mCachedDeviceManager.addDevice(mDevice1);
-        assertThat(cachedDevice1).isNotNull();
-        assertThat(cachedDevice1.getBtClass()).isEqualTo(DEVICE_CLASS_1);
-
-        final BluetoothClass newBluetoothClass = DEVICE_CLASS_2;
-        when(mDevice1.getBluetoothClass()).thenReturn(newBluetoothClass);
-        mCachedDeviceManager.onBtClassChanged(mDevice1);
-        assertThat(cachedDevice1.getBtClass()).isEqualTo(newBluetoothClass);
-    }
-
     /**
      * Test to verify onDeviceDisappeared().
      */