From e47ec14318f64c29bf16b5a6bb662bc19206d6b0 Mon Sep 17 00:00:00 2001
From: Pavlin Radoslavov <pavlin@google.com>
Date: Wed, 1 Jun 2016 22:25:18 -0700
Subject: [PATCH] Delay handleEnable() until Bluetooth state is OFF

During shutdown of the Bluetooth stack, if a request to
enable Bluetooth is received, the request is processed immediately.
As a result, we don't let the Bluetooth service to shutdown cleanly,
and the Bluetooth process with the native backend doesn't go away.
This creates various issues in the native backend stack.

Now, after an enable request is received, if necessary we delay
acting on it, until the Bluetooth state is OFF.

Bug: 17723234
Change-Id: I55db4bbd4f45227aa49eae996dcc328f76557a9b
---
 .../server/BluetoothManagerService.java       | 72 ++++++++-----------
 1 file changed, 31 insertions(+), 41 deletions(-)

diff --git a/services/core/java/com/android/server/BluetoothManagerService.java b/services/core/java/com/android/server/BluetoothManagerService.java
index 1f88be55ec6b6..3eadb5ca73160 100644
--- a/services/core/java/com/android/server/BluetoothManagerService.java
+++ b/services/core/java/com/android/server/BluetoothManagerService.java
@@ -639,19 +639,6 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
             Slog.d(TAG,"enable():  mBluetooth =" + mBluetooth +
                     " mBinding = " + mBinding + " mState = " + mState);
         }
-        // We do not honor ON requests when the adapter is already turned ON or in the process of
-        // turning ON.
-        // As a protective mechanism to make sure that the native stack gets cleaned up properly
-        // before turning it back ON we ignore requests while the bluetooth is turning OFF.
-        // Bug: b/28318203
-        if (mState == BluetoothAdapter.STATE_BLE_TURNING_OFF ||
-            mState == BluetoothAdapter.STATE_TURNING_OFF ||
-            mState == BluetoothAdapter.STATE_ON ||
-            mState == BluetoothAdapter.STATE_BLE_ON ||
-            mState == BluetoothAdapter.STATE_TURNING_ON ||
-            mState == BluetoothAdapter.STATE_BLE_TURNING_ON) {
-            return false;
-        }
 
         synchronized(mReceiver) {
             mQuietEnableExternal = false;
@@ -701,6 +688,7 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
             mBluetoothLock.writeLock().lock();
             if (mUnbinding) return;
             mUnbinding = true;
+            mHandler.removeMessages(MESSAGE_BLUETOOTH_STATE_CHANGE);
             if (mBluetooth != null) {
                 //Unregister callback object
                 try {
@@ -1165,7 +1153,31 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
                     }
                     mHandler.removeMessages(MESSAGE_RESTART_BLUETOOTH_SERVICE);
                     mEnable = true;
-                    handleEnable(msg.arg1 == 1);
+                    if (mBluetooth == null) {
+                        handleEnable(msg.arg1 == 1);
+                    } else {
+                        //
+                        // We need to wait until transitioned to STATE_OFF and
+                        // the previous Bluetooth process has exited. The
+                        // waiting period has three components:
+                        // (a) Wait until the local state is STATE_OFF. This
+                        //     is accomplished by "waitForOnOff(false, true)".
+                        // (b) Wait until the STATE_OFF state is updated to
+                        //     all components.
+                        // (c) Wait until the Bluetooth process exits, and
+                        //     ActivityManager detects it.
+                        // The waiting for (b) and (c) is accomplished by
+                        // delaying the MESSAGE_RESTART_BLUETOOTH_SERVICE
+                        // message. On slower devices, that delay needs to be
+                        // on the order of (2 * SERVICE_RESTART_TIME_MS).
+                        //
+                        waitForOnOff(false, true);
+                        mQuietEnable = (msg.arg1 == 1);
+                        Message restartMsg = mHandler.obtainMessage(
+                                MESSAGE_RESTART_BLUETOOTH_SERVICE);
+                        mHandler.sendMessageDelayed(restartMsg,
+                                2 * SERVICE_RESTART_TIME_MS);
+                    }
                     break;
 
                 case MESSAGE_DISABLE:
@@ -1617,14 +1629,11 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
                 if (newState == BluetoothAdapter.STATE_OFF) {
                     // If Bluetooth is off, send service down event to proxy objects, and unbind
                     if (DBG) Slog.d(TAG, "Bluetooth is complete turn off");
-                    if (canUnbindBluetoothService()) {
-                        if (DBG) Slog.d(TAG, "Good to unbind!");
-                        sendBluetoothServiceDownCallback();
-                        unbindAndFinish();
-                        sendBleStateChanged(prevState, newState);
-                        // Don't broadcast as it has already been broadcast before
-                        isStandardBroadcast = false;
-                    }
+                    sendBluetoothServiceDownCallback();
+                    unbindAndFinish();
+                    sendBleStateChanged(prevState, newState);
+                    // Don't broadcast as it has already been broadcast before
+                    isStandardBroadcast = false;
 
                 } else if (!intermediate_off) {
                     // connect to GattService
@@ -1726,25 +1735,6 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
                              quietMode ? 1 : 0, 0));
     }
 
-    private boolean canUnbindBluetoothService() {
-        try {
-            //Only unbind with mEnable flag not set
-            //For race condition: disable and enable back-to-back
-            //Avoid unbind right after enable due to callback from disable
-            //Only unbind with Bluetooth at OFF state
-            //Only unbind without any MESSAGE_BLUETOOTH_STATE_CHANGE message
-            mBluetoothLock.readLock().lock();
-            if (mEnable || (mBluetooth == null)) return false;
-            if (mHandler.hasMessages(MESSAGE_BLUETOOTH_STATE_CHANGE)) return false;
-            return (mBluetooth.getState() == BluetoothAdapter.STATE_OFF);
-        } catch (RemoteException e) {
-            Slog.e(TAG, "getState()", e);
-        } finally {
-            mBluetoothLock.readLock().unlock();
-        }
-        return false;
-    }
-
     private void recoverBluetoothServiceFromError() {
         Slog.e(TAG,"recoverBluetoothServiceFromError");
         try {