Merge pull request #7624 from Snuffleupagus/yury-fake-cloning

Adding "proper" message port for fake worker.

src/display/api.js

@@ -12,7 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/* globals pdfjsFilePath, pdfjsVersion, pdfjsBuild */
+/* globals pdfjsFilePath, pdfjsVersion, pdfjsBuild, WeakMap */
 
 'use strict';
 
@@ -50,6 +50,7 @@ var deprecated = sharedUtil.deprecated;
 var getVerbosityLevel = sharedUtil.getVerbosityLevel;
 var info = sharedUtil.info;
 var isInt = sharedUtil.isInt;
+var isArray = sharedUtil.isArray;
 var isArrayBuffer = sharedUtil.isArrayBuffer;
 var isSameOrigin = sharedUtil.isSameOrigin;
 var loadJpegStream = sharedUtil.loadJpegStream;
@@ -1075,6 +1076,84 @@ var PDFWorker = (function PDFWorkerClosure() {
     return fakeWorkerFilesLoadedCapability.promise;
   }
 
+  function FakeWorkerPort(defer) {
+    this._listeners = [];
+    this._defer = defer;
+    this._deferred = Promise.resolve(undefined);
+  }
+  FakeWorkerPort.prototype = {
+    postMessage: function (obj, transfers) {
+      function cloneValue(value) {
+        // Trying to perform a structured clone close to the spec, including
+        // transfers.
+        if (typeof value !== 'object' || value === null) {
+          return value;
+        }
+        if (cloned.has(value)) { // already cloned the object
+          return cloned.get(value);
+        }
+        var result;
+        var buffer;
+        if ((buffer = value.buffer) && isArrayBuffer(buffer)) {
+          // We found object with ArrayBuffer (typed array).
+          var transferable = transfers && transfers.indexOf(buffer) >= 0;
+          if (value === buffer) {
+            // Special case when we are faking typed arrays in compatibility.js.
+            result = value;
+          } else if (transferable) {
+            result = new value.constructor(buffer, value.byteOffset,
+                                           value.byteLength);
+          } else {
+            result = new value.constructor(value);
+          }
+          cloned.set(value, result);
+          return result;
+        }
+        result = isArray(value) ? [] : {};
+        cloned.set(value, result); // adding to cache now for cyclic references
+        // Cloning all value and object properties, however ignoring properties
+        // defined via getter.
+        for (var i in value) {
+          var desc, p = value;
+          while (!(desc = Object.getOwnPropertyDescriptor(p, i))) {
+            p = Object.getPrototypeOf(p);
+          }
+          if (typeof desc.value === 'undefined' ||
+              typeof desc.value === 'function') {
+            continue;
+          }
+          result[i] = cloneValue(desc.value);
+        }
+        return result;
+      }
+
+      if (!this._defer) {
+        this._listeners.forEach(function (listener) {
+          listener.call(this, {data: obj});
+        }, this);
+        return;
+      }
+
+      var cloned = new WeakMap();
+      var e = {data: cloneValue(obj)};
+      this._deferred.then(function () {
+        this._listeners.forEach(function (listener) {
+          listener.call(this, e);
+        }, this);
+      }.bind(this));
+    },
+    addEventListener: function (name, listener) {
+      this._listeners.push(listener);
+    },
+    removeEventListener: function (name, listener) {
+      var i = this._listeners.indexOf(listener);
+      this._listeners.splice(i, 1);
+    },
+    terminate: function () {
+      this._listeners = [];
+    }
+  };
+
   function createCDNWrapper(url) {
     // We will rely on blob URL's property to specify origin.
     // We want this function to fail in case if createObjectURL or Blob do not
@@ -1244,24 +1323,11 @@ var PDFWorker = (function PDFWorkerClosure() {
           return;
         }
 
-        // If we don't use a worker, just post/sendMessage to the main thread.
-        var port = {
-          _listeners: [],
-          postMessage: function (obj) {
-            var e = {data: obj};
-            this._listeners.forEach(function (listener) {
-              listener.call(this, e);
-            }, this);
-          },
-          addEventListener: function (name, listener) {
-            this._listeners.push(listener);
-          },
-          removeEventListener: function (name, listener) {
-            var i = this._listeners.indexOf(listener);
-            this._listeners.splice(i, 1);
-          },
-          terminate: function () {}
-        };
+        // We cannot turn on proper fake port simulation (this includes
+        // structured cloning) when typed arrays are not supported. Relying
+        // on a chance that messages will be sent in proper order.
+        var isTypedArraysPresent = Uint8Array !== Float32Array;
+        var port = new FakeWorkerPort(isTypedArraysPresent);
         this._port = port;
 
         // All fake workers use the same port, making id unique.