wip: synchronize on converging gateway

lib/simulator/behaviors/InclusiveGatewayBehavior.js

@@ -1,5 +1,5 @@
 import {
-  filterSequenceFlows
+  filterSequenceFlows, isSequenceFlow
 } from '../util/ModelUtil';
 
 
@@ -14,7 +14,30 @@ export default function InclusiveGatewayBehavior(
 }
 
 InclusiveGatewayBehavior.prototype.enter = function(context) {
-  this._simulator.exit(context);
+  const {
+    scope,
+    element
+  } = context;
+
+  const incomingSequenceFlows = filterSequenceFlows(element.incoming);
+
+  if (incomingSequenceFlows.length === 1) {
+    return this._simulator.exit(context);
+  }
+
+  const {
+    parent: parentScope
+  } = scope;
+
+  const sameParentScopes = this._simulator.findScopes(scope => (
+    scope.parent === parentScope && scope.element !== element));
+
+  // There are still some tokens to wait for.
+  if (this._canReachAnyScope(sameParentScopes, element)) {
+    return;
+  }
+
+  this._join(context);
 };
 
 InclusiveGatewayBehavior.prototype.exit = function(context) {
@@ -52,7 +75,54 @@ InclusiveGatewayBehavior.prototype.exit = function(context) {
   }
 };
 
+InclusiveGatewayBehavior.prototype._join = function(context) {
+  const elementScopes = this._simulator.findScopes({
+    parent: context.parent,
+    element: context.element
+  });
+
+  for (const childScope of elementScopes) {
+
+    if (childScope !== context.scope) {
+
+      // complete joining child scope
+      this._simulator.destroyScope(childScope.complete(), context.scope);
+    }
+  }
+
+  this._simulator.exit(context);
+};
+
+InclusiveGatewayBehavior.prototype._canReachAnyScope = function(scopes, currentElement, traversed = new Set()) {
+  if (traversed.has(currentElement)) {
+    return false;
+  }
+
+  if (anyScopeIsOnElement(scopes, currentElement)) {
+    return true;
+  }
+
+  if (isSequenceFlow(currentElement)) {
+    return this._canReachAnyScope(scopes, currentElement.source, traversed);
+  }
+
+
+  const incomingFlows = filterSequenceFlows(currentElement.incoming);
+
+  for (const flow of incomingFlows) {
+    if (this._canReachAnyScope(scopes, flow, traversed)) {
+      return true;
+    }
+  }
+
+  return false;
+};
+
 InclusiveGatewayBehavior.$inject = [
   'simulator',
   'activityBehavior'
-];
+];
+
+function anyScopeIsOnElement(scopes, element) {
+  return scopes.some(scope => scope.element === element);
+}