Add options and a browser-action popup.

go-back-with-backspace/pages/popup.js

Index: go-back-with-backspace/pages/popup.js
diff --git a/go-back-with-backspace/pages/popup.js b/go-back-with-backspace/pages/popup.js
new file mode 100644
index 0000000000000000000000000000000000000000..aa4666b36a9a700dd2dbb537e8395eceb768379d
--- /dev/null
+++ b/go-back-with-backspace/pages/popup.js
@@ -0,0 +1,125 @@
+// Copyright 2016 Google Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Return true if the extension is permitted to run on the given URL, with
+// the indicated permission for file:// schemes.
+function urlAllowed(url, file_ok) {
+  // Extensions are prohibited on the Chrome Web Store.
+  if (url.startsWith('https://chrome.google.com/webstore/'))
+    return false;
+
+  // Extensions are permitted to run on pages with schemes http, https, and
+  // ftp, plus file if enabled.
+  if (url.startsWith('http://') ||
+      url.startsWith('https://') ||
+      url.startsWith('ftp://'))
+    return true;
+
+  if (file_ok && url.startsWith('file://'))
+    return true;
+
+  return false;
+}
+
+// Update the popup display depending on the current options and the URL of
+// the current page.
+function updatePopup(options, url) {
+  var button = document.getElementById('list_edit_button');
+
+  if (!urlAllowed(url, options.file_ok)) {
+    button.textContent = chrome.i18n.getMessage('popupAddBlacklist');
+    button.disabled = true;
+    setStatusError('popupDisallowedURL');
+  } else if (options.blacklist.includes(url)) {
+    button.textContent = chrome.i18n.getMessage('popupRemoveBlacklist');
+  } else {
+    button.textContent = chrome.i18n.getMessage('popupAddBlacklist');
+  }
+
+  // If the current page is prohibited because it's a file:// scheme, show a
+  // link to chrome://extensions, where that setting can be changed.
+  if (!options.file_ok && url.startsWith('file://')) {
+    document.getElementById('file_url_message').hidden = false;
+    document.getElementById('status').hidden = true;
+  }
+}
+
+// Set the status text and display it in the error style.
+function setStatusError(message_id, placeholder) {
+  setStatus(message_id, placeholder);
+  document.getElementById('status').classList.add('error');
+}
+
+// Set the status text.
+function setStatus(message_id, placeholder) {
+  var status = document.getElementById('status');
+  if (placeholder === undefined)
+    status.textContent = chrome.i18n.getMessage(message_id);
+  else
+    status.textContent = chrome.i18n.getMessage(message_id, placeholder);
+}
+
+// Initialize the page.
+function init() {
+  LoadInternationalizedStrings();
+
+  // Load the active tab's URL, then set up page features that depend on it.
+  chrome.tabs.query({active: true, currentWindow: true}, function(tabList) {
+    var url = tabList[0].url;
+    var element = document.getElementById('current_url');
+    element.textContent = chrome.i18n.getMessage('popupCurrentURL', url);
+
+    // Load settings.
+    var options = {};
+    chrome.storage.sync.get({
+      blacklist: [],
+      disableInApplets: true,
+      whitelist: []
+    }, function(items) {
+      options = items;
+      // Read the extension file-access permission and update the popup UI.
+      chrome.extension.isAllowedFileSchemeAccess(function(file_ok) {
+        options.file_ok = file_ok;
+        updatePopup(options, url);
+      });
+    });
+
+    // Set event handlers that depend on the URL.
+    document.getElementById('list_edit_button').onclick = function() {
+      var index = options.blacklist.indexOf(url);
+      if (index > -1)
+        options.blacklist.splice(index, 1);
+      else
+        options.blacklist.push(url);
+
+      chrome.storage.sync.set({
+        blacklist: options.blacklist,
+        whitelist: options.whitelist
+      }, function() {
+        if (chrome.runtime.lastError) {
+          setStatusError('errorSaving', chrome.runtime.lastError.message);
+        } else {
+          updatePopup(options, url);
+          setStatus('popupStatusSaved');
+        }
+      });
+    };
+
+    document.getElementById('report_page').onclick = function() {
+      reportPage(url);
+    };
+  });
+
+  // Set event handlers that don't need the URL.
+  document.getElementById('open_options').onclick = function() {
+    chrome.runtime.openOptionsPage();
+  };
+
+  document.getElementById('open_extensions').onclick = function() {
+    chrome.tabs.create({url: 'chrome://extensions', active:true});
+    window.close();
+  };
+}
+
+window.addEventListener('load', init, false);