Don't show page share button on eLife pages

Don't show the "Share this page" button in the top-right of the sidebar
on pages, such as eLife's, that have both an embedded Hypothesis client
and a services config including their own `authority` string.

The "Share this page" button is a Via link, and Via doesn't work with
pages using a third-party authority config.

Fixes https://github.com/hypothesis/client/issues/615

src/sidebar/components/test/top-bar-test.js

 'use strict';
 
 var angular = require('angular');
+var proxyquire = require('proxyquire');
 
 var util = require('../../directive/test/util');
 
 describe('topBar', function () {
   var fakeSettings = {};
+  var fakeIsThirdPartyService = sinon.stub();
 
   before(function () {
     angular.module('app', [])
-      .component('topBar', require('../top-bar'))
+      .component('topBar', proxyquire('../top-bar', {
+        '../util/is-third-party-service': fakeIsThirdPartyService,
+        '@noCallThru': true,
+      }))
       .component('loginControl', {
         bindings: require('../login-control').bindings,
       })
@@ -25,6 +30,9 @@ describe('topBar', function () {
     angular.mock.module('app', {
       settings: fakeSettings,
     });
+
+    fakeIsThirdPartyService.reset();
+    fakeIsThirdPartyService.returns(false);
   });
 
   function applyUpdateBtn(el) {
@@ -87,6 +95,39 @@ describe('topBar', function () {
     assert.called(onLogout);
   });
 
+  it("checks whether we're using a third-party service", function () {
+    createTopBar();
+
+    assert.called(fakeIsThirdPartyService);
+    assert.alwaysCalledWithExactly(fakeIsThirdPartyService, fakeSettings);
+  });
+
+  context('when using a first-party service', function () {
+    it('shows the share page button', function () {
+      var el = createTopBar();
+      // I want the DOM element, not AngularJS's annoying angular.element
+      // wrapper object.
+      el = el [0];
+
+      assert.isNotNull(el.querySelector('[title="Share this page"]'));
+    });
+  });
+
+  context('when using a third-party service', function () {
+    beforeEach(function() {
+      fakeIsThirdPartyService.returns(true);
+    });
+
+    it("doesn't show the share page button", function () {
+      var el = createTopBar();
+      // I want the DOM element, not AngularJS's annoying angular.element
+      // wrapper object.
+      el = el [0];
+
+      assert.isNull(el.querySelector('[title="Share this page"]'));
+    });
+  });
+
   it('displays the share page when "Share this page" is clicked', function () {
     var onSharePage = sinon.stub();
     var el = createTopBar({ onSharePage: onSharePage });

src/sidebar/components/top-bar.js

 'use strict';
 
+var isThirdPartyService = require('../util/is-third-party-service');
+
 module.exports = {
   controllerAs: 'vm',
   //@ngInject
@@ -9,6 +11,10 @@ module.exports = {
     } else {
       this.isThemeClean = false;
     }
+
+    this.showSharePageButton = function () {
+      return !isThirdPartyService(settings);
+    };
   },
   bindings: {
     auth: '<',

src/sidebar/templates/top-bar.html

@@ -48,6 +48,7 @@
     </sort-dropdown>
     <a class="top-bar__btn"
        ng-click="vm.onSharePage()"
+       ng-if="vm.showSharePageButton()"
        title="Share this page">
       <i class="h-icon-annotation-share"></i>
     </a>

src/sidebar/util/is-third-party-service.js

+'use strict';
+
+const serviceConfig = require('../service-config');
+
+/**
+ * Return `true` if the first configured service is a "third-party" service.
+ *
+ * Return `true` if the first custom annotation service configured in the
+ * services array in the host page is a third-party service, `false` otherwise.
+ *
+ * If no custom annotation services are configured then return `false`.
+ *
+ * @param {Object} settings - the sidebar settings object
+ *
+ */
+function isThirdPartyService(settings) {
+  const service = serviceConfig(settings);
+
+  if (service === null) {
+    return false;
+  }
+
+  if (!service.hasOwnProperty('authority')) {
+    return false;
+  }
+
+  return (service.authority !== settings.authDomain);
+}
+
+module.exports = isThirdPartyService;

src/sidebar/util/test/is-third-party-service-test.js

+'use strict';
+
+const proxyquire = require('proxyquire');
+
+describe('sidebar.util.isThirdPartyService', () => {
+  let fakeServiceConfig;
+  let fakeSettings;
+  let isThirdPartyService;
+
+  beforeEach(() => {
+    fakeServiceConfig = sinon.stub();
+    fakeSettings = {authDomain: 'hypothes.is'};
+
+    isThirdPartyService = proxyquire('../is-third-party-service', {
+      '../service-config': fakeServiceConfig,
+      '@noCallThru': true,
+    });
+  });
+
+  it('returns false for first-party services', () => {
+    fakeServiceConfig.returns({authority: 'hypothes.is'});
+
+    assert.isFalse(isThirdPartyService(fakeSettings));
+  });
+
+  it('returns true for third-party services', () => {
+    fakeServiceConfig.returns({authority: 'elifesciences.org'});
+
+    assert.isTrue(isThirdPartyService(fakeSettings));
+  });
+
+  it("returns false if there's no service config", () => {
+    fakeServiceConfig.returns(null);
+
+    assert.isFalse(isThirdPartyService(fakeSettings));
+  });
+
+  // It's not valid for a service config object to not contain an authority
+  // (authority is a required field) but at the time of writing the config
+  // isn't validated when it's read in, so make sure that isThirdPartyService()
+  // handles invalid configs.
+  it("returns false if the service config doesn't contain an authority", () => {
+    fakeServiceConfig.returns({});
+
+    assert.isFalse(isThirdPartyService(fakeSettings));
+  });
+});