Dactyloidae iOS initial commit

mobile/ios/Client/Frontend/Metadata Parsing/MetadataHelper.js

@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+(function() {
+"use strict";
+
+if (!window.__firefox__) {
+  Object.defineProperty(window, '__firefox__', {
+    enumerable: false,
+    configurable: false,
+    writable: false,
+    value: {}
+  });
+}
+
+function MetadataWrapper(metadataparser) {
+  var dataURIRegex = /^\s*data:([a-z]+\/[a-z]+(;[a-z\-]+\=[a-z\-]+)?)?(;base64)?,[a-z0-9\!\$\&\'\,\(\)\*\+\,\;\=\-\.\_\~\:\@\/\?\%\s]*\s*$/i;
+
+  function isDataURI(s) {
+    return !!s.match(dataURIRegex);
+  }
+                                                                                  
+  function getDataUri(url, callback) {
+    var image = new Image();
+    image.onload = function() {
+      try {
+        var canvas = document.createElement('canvas');
+        canvas.width = this.naturalWidth; // or 'width' if you want a special/scaled size
+        canvas.height = this.naturalHeight; // or 'height' if you want a special/scaled size
+        canvas.getContext('2d').drawImage(this, 0, 0);
+        var dataURI = canvas.toDataURL();
+        callback(dataURI);
+      } catch (exception) {
+        callback(false);
+      }
+    };
+
+    image.src = url;
+  }
+
+  function metadataCallback(metadata) {
+    window.__firefox__.pageMetadata = metadata;
+    webkit.messageHandlers.metadataMessageHandler.postMessage(metadata);
+  }
+ 
+  this.extractMetadata = function() {
+    var metadata = metadataparser.getMetadata(window.document, document.URL);
+    var imageURL = metadata["image"];
+    if (imageURL) {
+      if (isDataURI(imageURL)) {
+        metadata["image_data_uri"] = imageURL;
+        metadataCallback(metadata);
+      } else {
+        getDataUri(imageURL, function(dataURI) {
+          if (dataURI) {
+            metadata["image_data_uri"] = dataURI;
+          }
+          metadataCallback(metadata);
+        });
+      }
+    } else {
+      metadataCallback(metadata);
+    }
+  };
+}
+
+Object.defineProperty(window.__firefox__, 'metadata', {
+  enumerable: false,
+  configurable: false,
+  writable: false,
+  value: Object.freeze(new MetadataWrapper(metadataparser))
+});
+metadataparser = undefined;
+
+})();