fix(Import): forgive broken di (missing bpmnElement attr)

Related to #8

lib/BpmnTreeWalker.js

@@ -1,6 +1,6 @@
 var _ = require('lodash');
 
-function BpmnTraverser(visitor) {
+function BpmnTraverser(handler) {
 
   var elementDiMap = {};
   var elementGfxMap = {};
@@ -19,8 +19,8 @@ function BpmnTraverser(visitor) {
 
   function visit(element, di, ctx) {
 
-    // call visitor
-    var gfx = visitor(element, di, ctx);
+    // call handler
+    var gfx = handler.element(element, di, ctx);
 
     // and log returned result
     elementGfxMap[element.id] = gfx;
@@ -36,6 +36,9 @@ function BpmnTraverser(visitor) {
     }
   }
 
+  function logError(message, context) {
+    handler.error(message, context);
+  }
 
   ////// DI handling ////////////////////////////
 
@@ -45,7 +48,11 @@ function BpmnTraverser(visitor) {
 
   function registerDi(element) {
     var bpmnElement = element.bpmnElement;
-    elementDiMap[bpmnElement.id] = element;
+    if (bpmnElement) {
+      elementDiMap[bpmnElement.id] = element;
+    } else {
+      logError('no bpmnElement for <' + element.$type + '#' + element.id + '>', { element: element });
+    }
   }
 
   function getDi(bpmnElement) {

lib/Importer.js

@@ -8,29 +8,36 @@ function importBpmnDiagram(diagram, definitions, done) {
 
   var shapes = {};
 
-  var visitor = function(element, di, parent) {
+  var visitor = {
 
-    var shape;
+    element: function(element, di, parent) {
 
-    if (di.$type === 'bpmndi:BPMNShape') {
-      var bounds = di.bounds;
+      var shape;
 
-      shape = { id: element.id, type: element.$type, x: bounds.x, y: bounds.y, width: bounds.width, height: bounds.height, parent: parent };
+      if (di.$type === 'bpmndi:BPMNShape') {
+        var bounds = di.bounds;
 
-      canvas.addShape(shape);
-    } else {
+        shape = { id: element.id, type: element.$type, x: bounds.x, y: bounds.y, width: bounds.width, height: bounds.height, parent: parent };
 
-      var waypoints = _.collect(di.waypoint, function(p) {
-        return { x: p.x, y: p.y };
-      });
+        canvas.addShape(shape);
+      } else {
 
-      shape = { id: element.id, type: element.$type, waypoints: waypoints };
-      canvas.addConnection(shape);
+        var waypoints = _.collect(di.waypoint, function(p) {
+          return { x: p.x, y: p.y };
+        });
+
+        shape = { id: element.id, type: element.$type, waypoints: waypoints };
+        canvas.addConnection(shape);
+      }
+
+      shapes[element.id] = shape;
+
+      return shape;
+    },
+    
+    error: function(message, context) {
+      console.warn('[import]', message, context);
     }
-
-    shapes[element.id] = shape;
-
-    return shape;
   };
 
   var walker = new BpmnTreeWalker(visitor);

test/fixtures/bpmn/error/di-no-bpmn-element.bpmn

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn2:definitions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:bpmn2="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xsi:schemaLocation="http://www.omg.org/spec/BPMN/20100524/MODEL BPMN20.xsd" id="test" targetNamespace="http://bpmn.io/schema/bpmn">
+  <bpmn2:process id="Process_1" isExecutable="false">
+    <bpmn2:startEvent id="StartEvent_1"/>
+  </bpmn2:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
+      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2">
+        <dc:Bounds height="36.0" width="36.0" x="412.0" y="240.0"/>
+      </bpmndi:BPMNShape>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn2:definitions>

test/spec/node/import/BpmnTreeWalkerSpec.js

@@ -22,44 +22,74 @@ describe('BpmnTreeWalker', function() {
   }
 
 
+  /**
+   * A simple handler that records what a tree walker processes
+   */
+  function RecordingHandler() {
+
+    var elements = [];
+    var errors = [];
+
+    function handleElement(element, di, ctx) {
+      var id = element.id;
+
+      elements.push({ id: id, parent: ctx });
+
+      return id;
+    }
+
+    function handleError(message, context) {
+      errors.push({ message: message, context: context });
+    }
+
+    this.element = handleElement;
+    this.error = handleError;
+
+    this._errors = errors;
+    this._elements = elements;
+  }
+
+  function readBpmn(file, fn, done) {
+    readFile(file, 'bpmn:Definitions', function(err, definitions) {
+
+      if (err) {
+        return done(err);
+      }
+
+      fn(definitions);
+
+      done();
+    });
+  }
+
+
+  /**
+   * Expect a certain render order when parsing the given file contents.
+   * 
+   * Call done when done.
+   */
+  function expectWalkOrder(file, expectedOrder, done) {
+
+    readBpmn(file, function(definitions) {
+
+      var handler = new RecordingHandler();
+
+      new BpmnTreeWalker(handler).handleDefinitions(definitions);
+
+      expect(handler._elements).toDeepEqual(expectedOrder);
+      expect(handler._errors.length).toBe(0);
+
+    }, done);
+  }
+
+
   beforeEach(Matchers.add);
 
   var bpmnModel = BpmnModel.instance();
 
+
   describe('should walk', function() {
 
-    /**
-     * Expect a certain render order when parsing the given file contents.
-     * 
-     * Call done when done.
-     */
-    function expectWalkOrder(file, expectedOrder, done) {
-
-      readFile(file, 'bpmn:Definitions', function(err, definitions) {
-
-        if (err) {
-          done(err);
-          return;
-        }
-
-        var actualOrder = [];
-
-        var visitor = function(element, di, ctx) {
-          var id = element.id;
-
-          actualOrder.push({ id: id, parent: ctx });
-
-          return id;
-        };
-
-        new BpmnTreeWalker(visitor).handleDefinitions(definitions);
-
-        expect(actualOrder).toDeepEqual(expectedOrder);
-
-        done();
-      });
-    }
-
     it('process / sub process', function(done) {
 
       // given
@@ -195,4 +225,30 @@ describe('BpmnTreeWalker', function() {
     });
 
   });
+
+
+  describe('should handle errors', function() {
+
+    it('missing bpmnElement on di', function(done) {
+
+      // given
+      readBpmn('error/di-no-bpmn-element.bpmn', function(definitions) {
+
+        // when
+        var handler = new RecordingHandler();
+        new BpmnTreeWalker(handler).handleDefinitions(definitions);
+
+        expect(handler._elements).toDeepEqual([]);
+        expect(handler._errors.length).toBe(1);
+
+        var error = handler._errors[0];
+
+        expect(error.message).toBe('no bpmnElement for <bpmndi:BPMNShape#_BPMNShape_StartEvent_2>');
+      }, done);
+
+    });
+
+  });
+
+
 });