Add async functionality to Action Queue (#543)

* Add async functionality to Action Queue

* Offload all listener methods from Main thread.

Author: hborisoff

AndroidSDKCore/src/main/java/com/leanplum/actions/LeanplumActions.kt

@@ -117,4 +117,7 @@ object LeanplumActions {
    */
   @JvmStatic
   fun isQueueEnabled() = ActionManager.getInstance().isEnabled
+
+  @JvmStatic
+  var useWorkerThreadForDecisionHandlers = false
 }

AndroidSDKCore/src/main/java/com/leanplum/actions/internal/ActionManagerExecution.kt

@@ -22,7 +22,9 @@
 package com.leanplum.actions.internal
 
 import androidx.annotation.UiThread
+import com.leanplum.ActionContext
 import com.leanplum.Leanplum
+import com.leanplum.actions.LeanplumActions
 import com.leanplum.actions.MessageDisplayChoice
 import com.leanplum.callbacks.VariablesChangedCallback
 import com.leanplum.internal.*
@@ -104,7 +106,9 @@ private fun ActionManager.performActionsImpl() {
 
   // do not continue if we have action running
   if (currentAction != null) {
-    prioritizePushNotificationActions()
+    if (!LeanplumActions.useWorkerThreadForDecisionHandlers) { // disable prioritization with worker thread
+      prioritizePushNotificationActions()
+    }
     return
   }
 
@@ -122,6 +126,15 @@ private fun ActionManager.performActionsImpl() {
     return
   }
 
+  if (LeanplumActions.useWorkerThreadForDecisionHandlers) {
+    OperationQueue.sharedInstance().addActionOperation { askUserAndPresentAction(currentContext) }
+  } else {
+    askUserAndPresentAction(currentContext)
+  }
+}
+
+private fun ActionManager.askUserAndPresentAction(currentContext: ActionContext) {
+
   // decide if we are going to display the message
   // by calling delegate and let it decide what we are supposed to do
   val displayDecision = messageDisplayController?.shouldDisplayMessage(currentContext)
@@ -162,16 +175,34 @@ private fun ActionManager.performActionsImpl() {
 
   // 3) set dismiss block
   currentContext.setActionDidDismiss {
-    Log.d("[ActionManager]: actionDidDismiss: ${currentContext}.")
-    messageDisplayListener?.onMessageDismissed(currentContext)
-    currentAction = null // stop executing current action
-    performActions()
+    val dismissOperation = {
+      Log.d("[ActionManager]: actionDidDismiss: ${currentContext}.")
+      messageDisplayListener?.onMessageDismissed(currentContext)
+      currentAction = null // stop executing current action
+      performActions()
+    }
+
+    if (LeanplumActions.useWorkerThreadForDecisionHandlers) {
+      OperationQueue.sharedInstance().addActionOperation(dismissOperation)
+    } else {
+      dismissOperation.invoke()
+    }
+
   }
 
   // 2) set the action block
   currentContext.setActionDidExecute { actionNamedContext ->
-    Log.d("[ActionManager]: actionDidExecute: ${actionNamedContext}.")
-    messageDisplayListener?.onActionExecuted(actionNamedContext.actionName(), actionNamedContext)
+    val actionExecutedOperation = {
+      Log.d("[ActionManager]: actionDidExecute: ${actionNamedContext}.")
+      messageDisplayListener?.onActionExecuted(actionNamedContext.actionName(), actionNamedContext)
+      Unit
+    }
+
+    if (LeanplumActions.useWorkerThreadForDecisionHandlers) {
+      OperationQueue.sharedInstance().addActionOperation(actionExecutedOperation)
+    } else {
+      actionExecutedOperation.invoke()
+    }
   }
 
   // 1) ask to present, return if it's not

AndroidSDKCore/src/main/java/com/leanplum/actions/internal/ActionManagerTriggering.kt

@@ -22,21 +22,43 @@
 package com.leanplum.actions.internal
 
 import com.leanplum.ActionContext
+import com.leanplum.actions.LeanplumActions
 import com.leanplum.internal.ActionManager
 import com.leanplum.internal.Log
+import com.leanplum.internal.OperationQueue
 
 fun ActionManager.trigger(
   context: ActionContext,
   priority: Priority = Priority.DEFAULT) {
 
-  trigger(listOf(context), priority)
+  if (LeanplumActions.useWorkerThreadForDecisionHandlers) {
+    OperationQueue.sharedInstance().addActionOperation {
+      triggerImpl(listOf(context), priority)
+    }
+  } else {
+    triggerImpl(listOf(context), priority)
+  }
 }
 
 fun ActionManager.trigger(
   contexts: List<ActionContext>,
   priority: Priority = Priority.DEFAULT,
   trigger: ActionsTrigger? = null) {
 
+  if (LeanplumActions.useWorkerThreadForDecisionHandlers) {
+    OperationQueue.sharedInstance().addActionOperation {
+      triggerImpl(contexts, priority, trigger)
+    }
+  } else {
+    triggerImpl(contexts, priority, trigger)
+  }
+}
+
+private fun ActionManager.triggerImpl(
+  contexts: List<ActionContext>,
+  priority: Priority = Priority.DEFAULT,
+  trigger: ActionsTrigger? = null) {
+
   if (contexts.isEmpty()) return
 
   // By default, add only one message to queue if `prioritizeMessages` is not implemented

AndroidSDKCore/src/main/java/com/leanplum/internal/ActionManager.java

@@ -67,7 +67,7 @@ public class ActionManager {
   private final ActionQueue queue = new ActionQueue();
   private final ActionQueue delayedQueue = new ActionQueue();
   private final Definitions definitions = new Definitions();
-  private Action currentAction;
+  private volatile Action currentAction;
   private boolean dismissOnPushOpened = true;
   private boolean continueOnActivityResumed = true;
 

AndroidSDKCore/src/main/java/com/leanplum/internal/OperationQueue.java

@@ -34,6 +34,7 @@ public class OperationQueue {
     private static OperationQueue instance;
 
     private static final String OPERATION_QUEUE_NAME = "com.leanplum.operation_queue";
+    private static final String ACTION_QUEUE_NAME = "com.leanplum.action_queue";
     private static final int OPERATION_QUEUE_PRIORITY = Process.THREAD_PRIORITY_DEFAULT;
 
     private HandlerThread handlerThread;
@@ -42,6 +43,9 @@ public class OperationQueue {
 
     private Executor executor = Executors.newCachedThreadPool();
 
+    private Handler actionsHandler;
+    private HandlerThread actionsThread;
+
     public static OperationQueue sharedInstance() {
         if (instance == null) {
             instance = new OperationQueue();
@@ -161,4 +165,18 @@ public void removeAllOperations() {
             handler.removeCallbacksAndMessages(null);
         }
     }
+
+    /**
+     * Add operation related to Action Queue. Will execute operations sequentially.
+     */
+    public void addActionOperation(Runnable operation) {
+        if (actionsHandler == null) {
+            actionsThread = new HandlerThread(ACTION_QUEUE_NAME, OPERATION_QUEUE_PRIORITY);
+            actionsThread.start();
+            actionsHandler = new Handler(actionsThread.getLooper());
+        }
+        if (operation != null) {
+            actionsHandler.post(operation);
+        }
+    }
 }