Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 92de8485 authored by Shai Barack's avatar Shai Barack
Browse files

Avoid races between nextMessage() and stackHasMessages() 

Apply ag/32896611 to ConcurrentMessageQueue for reference.

Bug: 396569494
Flag: EXEMPT - bugfix
Test: atest MessageQueueTest
Change-Id: I30261b54d0acd1befa3a049b8fe2eda51f27e2da
parent ad3850c3

core/java/android/os/ConcurrentMessageQueue/MessageQueue.java

+5 −14
Original line number Diff line number Diff line
@@ -148,10 +148,6 @@ public final class MessageQueue { 
            return mMessage.when;

        }



        boolean isRemovedFromStack() {

            return mRemovedFromStackValue;

        }



        boolean removeFromStack() {

            return sRemovedFromStack.compareAndSet(this, false, true);

        }
@@ -1221,16 +1217,10 @@ public final class MessageQueue { 
        StateNode bottom = getStateNode(top);



        /*

         * If the top node is a state node, there are no reachable messages.

         * If it's anything other than Active, we can quit as we know that next() is not

         * consuming items.

         * If the top node is Active then we know that next() is currently consuming items.

         * In that case we should wait next() has drained the stack.

         * If the top node is a state node, there are no reachable messages. We should still

         * wait for next to complete draining the stack.

         */

        if (top == bottom) {

            if (bottom != sStackStateActive) {

                return false;

            }

            waitForDrainCompleted();

            return false;

        }
@@ -1258,7 +1248,7 @@ public final class MessageQueue { 
                        }

                    }

                } else {

                    return true;

                    break;

                }

            }
@@ -1268,7 +1258,6 @@ public final class MessageQueue { 
                if (DEBUG) {

                    Log.d(TAG, "stackHasMessages next() is walking the stack, we must re-sample");

                }

                waitForDrainCompleted();

                break;

            }

            if (!n.isMessageNode()) {
@@ -1278,6 +1267,8 @@ public final class MessageQueue { 
            p = (MessageNode) n;

        }



        waitForDrainCompleted();



        return found;

    }