Merge pull request randdusing#687 from mes-indesign/fix/419

Fix out-of-order notifications on Android

Author: randdusing

plugin.xml

@@ -20,6 +20,7 @@
     </config-file>
     <source-file src="src/android/BluetoothLePlugin.java" target-dir="src/com/randdusing/bluetoothle" />
     <source-file src="src/android/Operation.java" target-dir="src/com/randdusing/bluetoothle" />
+    <source-file src="src/android/SequentialCallbackContext.java" target-dir="src/com/randdusing/bluetoothle" />
     <config-file target="AndroidManifest.xml" parent="/manifest">
       <uses-permission android:name="android.permission.BLUETOOTH"/>
       <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

src/android/BluetoothLePlugin.java

@@ -1844,7 +1844,7 @@ private boolean subscribeAction(Operation operation) {
 
     addCharacteristic(returnObj, characteristic);
 
-    CallbackContext checkExisting = GetCallback(characteristicUuid, connection, operationSubscribe);
+    SequentialCallbackContext checkExisting = GetSequentialCallbackContext(characteristicUuid, connection, operationSubscribe);
     if (checkExisting != null) {
       addProperty(returnObj, keyError, errorSubscription);
       addProperty(returnObj, keyMessage, logSubscribeAlready);
@@ -1878,7 +1878,7 @@ private boolean subscribeAction(Operation operation) {
       return false;
     }
 
-    AddCallback(characteristicUuid, connection, operationSubscribe, callbackContext);
+    AddSequentialCallbackContext(characteristicUuid, connection, operationSubscribe, callbackContext);
 
     //Write the descriptor value
     result = bluetoothGatt.writeDescriptor(descriptor);
@@ -1952,7 +1952,7 @@ private boolean unsubscribeAction(Operation operation) {
 
     addCharacteristic(returnObj, characteristic);
 
-    CallbackContext checkExisting = GetCallback(characteristicUuid, connection, operationSubscribe);
+    SequentialCallbackContext checkExisting = GetSequentialCallbackContext(characteristicUuid, connection, operationSubscribe);
     if (checkExisting == null) {
       addProperty(returnObj, keyError, errorSubscription);
       addProperty(returnObj, keyMessage, logUnsubscribeAlready);
@@ -3283,6 +3283,23 @@ private CallbackContext GetCallback(UUID characteristicUuid, HashMap<Object, Obj
     return (CallbackContext) characteristicCallbacks.get(operationType);
   }
 
+  private void AddSequentialCallbackContext(UUID characteristicUuid, HashMap<Object, Object> connection, String operationType, CallbackContext callbackContext) {
+    HashMap<Object, Object> characteristicCallbacks = EnsureCallback(characteristicUuid, connection);
+
+    characteristicCallbacks.put(operationType, new SequentialCallbackContext(callbackContext));
+  }
+
+  private SequentialCallbackContext GetSequentialCallbackContext(UUID characteristicUuid, HashMap<Object, Object> connection, String operationType) {
+    HashMap<Object, Object> characteristicCallbacks = (HashMap<Object, Object>) connection.get(characteristicUuid);
+
+    if (characteristicCallbacks == null) {
+      return null;
+    }
+
+    //This may return null
+    return (SequentialCallbackContext) characteristicCallbacks.get(operationType);
+  }
+
   private CallbackContext[] GetCallbacks(HashMap<Object, Object> connection) {
     ArrayList<CallbackContext> callbacks = new ArrayList<CallbackContext>();
 
@@ -3324,7 +3341,12 @@ private void GetMoreCallbacks(HashMap<Object, Object> lower, ArrayList<CallbackC
         continue;
       }
 
-      CallbackContext callback = (CallbackContext) lower.get(key);
+      CallbackContext callback;
+      if (key.equals(operationSubscribe)) {
+        callback = ((SequentialCallbackContext) lower.get(key)).getContext();
+      } else {
+        callback = (CallbackContext) lower.get(key);
+      }
 
       if (callback == null) {
         continue;
@@ -4175,7 +4197,7 @@ public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteris
 
       UUID characteristicUuid = characteristic.getUuid();
 
-      CallbackContext callbackContext = GetCallback(characteristicUuid, connection, operationSubscribe);
+      SequentialCallbackContext callbackContext = GetSequentialCallbackContext(characteristicUuid, connection, operationSubscribe);
 
       //If no callback, just return
       if (callbackContext == null) {
@@ -4192,9 +4214,7 @@ public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteris
       addPropertyBytes(returnObj, keyValue, characteristic.getValue());
 
       //Return the characteristic value
-      PluginResult result = new PluginResult(PluginResult.Status.OK, returnObj);
-      result.setKeepCallback(true);
-      callbackContext.sendPluginResult(result);
+      callbackContext.sendSequentialResult(returnObj);
     }
 
     @Override
@@ -4365,7 +4385,7 @@ public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descri
 
           callbackContext.success(returnObj);
         } else {
-          CallbackContext callbackContext = GetCallback(characteristicUuid, connection, operationSubscribe);
+          SequentialCallbackContext callbackContext = GetSequentialCallbackContext(characteristicUuid, connection, operationSubscribe);
 
           //If no callback, just return
           if (callbackContext == null) {
@@ -4376,7 +4396,7 @@ public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descri
 
           PluginResult pluginResult = new PluginResult(PluginResult.Status.OK, returnObj);
           pluginResult.setKeepCallback(true);
-          callbackContext.sendPluginResult(pluginResult);
+          callbackContext.getContext().sendPluginResult(pluginResult);
         }
 
         return;

src/android/SequentialCallbackContext.java

@@ -0,0 +1,48 @@
+// Inspiration taken from cordova-plugin-ble-central
+
+package com.randdusing.bluetoothle;
+
+import org.apache.cordova.CallbackContext;
+import org.apache.cordova.PluginResult;
+import java.util.ArrayList;
+import java.util.List;
+import org.json.JSONObject;
+
+public class SequentialCallbackContext {
+    private int sequence;
+    private CallbackContext context;
+
+    public SequentialCallbackContext(CallbackContext context) {
+        this.context = context;
+        this.sequence = 0;
+    }
+
+    private int getNextSequenceNumber() {
+        synchronized(this) {
+            return this.sequence++; 
+        }
+    }
+
+    public CallbackContext getContext() {
+      return this.context;
+    }
+
+    public PluginResult createSequentialResult(JSONObject returnObj) {
+        List<PluginResult> resultList = new ArrayList<PluginResult>(2);
+
+        PluginResult dataResult = new PluginResult(PluginResult.Status.OK, returnObj);
+        PluginResult sequenceResult = new PluginResult(PluginResult.Status.OK, this.getNextSequenceNumber()); 
+
+        resultList.add(dataResult);
+        resultList.add(sequenceResult);
+        
+        return new PluginResult(PluginResult.Status.OK, resultList);
+    }
+
+    public void sendSequentialResult(JSONObject returnObj) {
+        PluginResult result = this.createSequentialResult(returnObj);
+        result.setKeepCallback(true);
+
+        this.context.sendPluginResult(result);
+    }
+}

www/bluetoothle.js

@@ -1,5 +1,43 @@
 var bluetoothleName = "BluetoothLePlugin";
 var bluetoothle = {
+  _newReorderer: function(successCallback) {
+    let context = {
+      callback: successCallback,
+      onHold: {},
+      nextExpected: 0,
+    };
+    return bluetoothle._reorderCallback.bind(context);
+  },
+  _reorderCallback: function(obj, sequence) {
+    /**
+     * If there is not a sequence number present, just pass the callback through
+     * without reordering it.
+     */
+    if (sequence == null) {
+      this.callback(obj);
+      return;  
+    }
+
+    if (sequence != this.nextExpected) console.warn("Received out of order: expected " + this.nextExpected +" got " + sequence);
+
+    this.onHold[sequence] = obj;
+
+    bluetoothle._tryDispatchInOrder.bind(this)();
+  },
+  _tryDispatchInOrder: function() {
+    while (this.nextExpected in this.onHold) {
+      try {
+        let value = this.onHold[this.nextExpected];
+        delete this.onHold[this.nextExpected];
+
+        this.nextExpected += 1;
+
+        this.callback(value);
+      } catch (err) {
+        console.error("Error in callback in Reorderer", err);
+      }
+    }
+  },
   initialize: function(successCallback, params) {
     cordova.exec(successCallback, successCallback, bluetoothleName, "initialize", [params]);
   },
@@ -55,7 +93,7 @@ var bluetoothle = {
     cordova.exec(successCallback, errorCallback, bluetoothleName, "read", [params]);
   },
   subscribe: function(successCallback, errorCallback, params) {
-    cordova.exec(successCallback, errorCallback, bluetoothleName, "subscribe", [params]);
+    cordova.exec(bluetoothle._newReorderer(successCallback), errorCallback, bluetoothleName, "subscribe", [params]);
   },
   unsubscribe: function(successCallback, errorCallback, params) {
     cordova.exec(successCallback, errorCallback, bluetoothleName, "unsubscribe", [params]);