Move logic from viewer.js to chromecom.js

and also default to '' instead of DEFAULT_URL to avoid trying to
load a non-existent file when no file has been specified.

web/chromecom.js

@@ -14,35 +14,98 @@
  * limitations under the License.
  */
 
-/* globals chrome */
+/* globals chrome, PDFJS, PDFView */
 'use strict';
 
 var ChromeCom = (function ChromeComClosure() {
-  return {
-    /**
-     * Creates an event that the extension is listening for and will
-     * asynchronously respond by calling the callback.
-     * @param {String} action The action to trigger.
-     * @param {String} data Optional data to send.
-     * @param {Function} callback Optional response callback that will be called
-     * with one data argument. When the request cannot be handled, the callback
-     * is immediately invoked with no arguments.
-     */
-    request: function(action, data, callback) {
-      var message = {
-        action: action,
-        data: data
-      };
-      if (!chrome.runtime) {
-        console.error('chrome.runtime is undefined.');
-        if (callback) {
-          callback();
-        }
-      } else if (callback) {
-        chrome.runtime.sendMessage(message, callback);
-      } else {
-        chrome.runtime.sendMessage(message);
+  var ChromeCom = {};
+  /**
+   * Creates an event that the extension is listening for and will
+   * asynchronously respond by calling the callback.
+   *
+   * @param {String} action The action to trigger.
+   * @param {String} data Optional data to send.
+   * @param {Function} callback Optional response callback that will be called
+   * with one data argument. When the request cannot be handled, the callback
+   * is immediately invoked with no arguments.
+   */
+  ChromeCom.request = function ChromeCom_request(action, data, callback) {
+    var message = {
+      action: action,
+      data: data
+    };
+    if (!chrome.runtime) {
+      console.error('chrome.runtime is undefined.');
+      if (callback) {
+        callback();
       }
+    } else if (callback) {
+      chrome.runtime.sendMessage(message, callback);
+    } else {
+      chrome.runtime.sendMessage(message);
     }
   };
+
+  /**
+   * Opens a PDF file with the PDF viewer.
+   *
+   * @param {String} file Absolute URL of PDF file.
+   */
+  ChromeCom.openPDFFile = function ChromeCom_openPDFFile(file) {
+    // Expand drive:-URLs to filesystem URLs (Chrome OS)
+    file = file.replace(/^drive:/i,
+        'filesystem:' + location.origin + '/external/');
+
+    ChromeCom.request('getPDFStream', file, function(response) {
+      if (response) {
+        // We will only get a response when the streamsPrivate API is available.
+
+        var isFTPFile = /^ftp:/i.test(file);
+        var streamUrl = response.streamUrl;
+        if (streamUrl) {
+          console.log('Found data stream for ' + file);
+          PDFView.open(streamUrl, 0, undefined, undefined, {
+            length: response.contentLength
+          });
+          PDFView.setTitleUsingUrl(file);
+          return;
+        }
+        if (isFTPFile && !response.extensionSupportsFTP) {
+          // Stream not found, and it's loaded from FTP.
+          // When the browser does not support loading ftp resources over
+          // XMLHttpRequest, just reload the page.
+          // NOTE: This will not lead to an infinite redirect loop, because
+          // if the file exists, then the streamsPrivate API will capture the
+          // stream and send back the response. If the stream does not exist,
+          // a "Webpage not available" error will be shown (not the PDF Viewer).
+          location.replace(file);
+          return;
+        }
+      }
+      if (/^filesystem:/.test(file) && !PDFJS.disableWorker) {
+        // The security origin of filesystem:-URLs are not preserved when the
+        // URL is passed to a Web worker, (http://crbug.com/362061), so we have
+        // to create an intermediate blob:-URL as a work-around.
+        var resolveLocalFileSystemURL = window.resolveLocalFileSystemURL ||
+                                        window.webkitResolveLocalFileSystemURL;
+        resolveLocalFileSystemURL(file, function onResolvedFSURL(fileEntry) {
+          fileEntry.file(function(fileObject) {
+            var blobUrl = URL.createObjectURL(fileObject);
+            PDFView.open(blobUrl, 0, undefined, undefined, {
+              length: fileObject.size
+            });
+          });
+        }, function onFileSystemError(error) {
+          // This should not happen. When it happens, just fall back to the
+          // usual way of getting the File's data (via the Web worker).
+          console.warn('Cannot resolve file ' + file + ', ' + error.name + ' ' +
+                       error.message);
+          PDFView.open(file, 0);
+        });
+        return;
+      }
+      PDFView.open(file, 0);
+    });
+  };
+  return ChromeCom;
 })();