Add support for ${path} in auth.switch_account_url

Provide client-side interpolation of ${path} in this string when
generating the "Switch account" link.

This change also updates the GWT version of this link to simply
remove any ${path} elements. There doesn't seem to be a good way
to ensure the path would be updated as the location changes.

Bug: Issue 4884
Change-Id: I2070208b540efb3f9fb527e23dbbd220fc2d2dce

Documentation/config-gerrit.txt

@@ -397,8 +397,14 @@ the currently active account.  This is disabled by default except when
 the "Switch Account" link is displayed next to "Sign Out".
 +
 When `auth.type` does not normally enable this URL administrators may
-set this to `login/` or `$canonicalWebUrl/login`, allowing users to
+set this to `login/`, allowing users to begin a new web session. This value
-begin a new web session.
+is used as an href in PolyGerrit and the GWT UI, so absolute URLs like
+`https://someotherhost/login` work as well.
++
+If a ${path} parameter is included, then PolyGerrit will substitute the
+currently viewed path in the link. Be aware that this path will include
+a leading slash, so a value like this might be appropriate: `/login${path}`.
+Note: in the GWT UI this substitution for ${path} is *always* `/`.
 
 [[auth.cookiePath]]auth.cookiePath::
 +

gerrit-gwtui/src/main/java/com/google/gerrit/client/UserPopupPanel.java

@@ -52,8 +52,9 @@ public class UserPopupPanel extends PopupPanel {
       userEmail.setText(account.email());
     }
     if (showSettingsLink) {
-      if (Gerrit.info().auth().switchAccountUrl() != null) {
+      String switchAccountUrl = Gerrit.info().auth().switchAccountUrl();
-        switchAccount.setHref(Gerrit.info().auth().switchAccountUrl());
+      if (switchAccountUrl != null) {
+        switchAccount.setHref(switchAccountUrl.replace("${path}", "/"));
       } else if (Gerrit.info().auth().isDev() || Gerrit.info().auth().isOpenId()) {
         switchAccount.setHref(Gerrit.selfRedirect("/login"));
       } else {

polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.js

@@ -14,37 +14,75 @@
 (function() {
   'use strict';
 
+  var INTERPOLATE_URL_PATTERN = /\$\{([\w]+)\}/g;
+
   Polymer({
     is: 'gr-account-dropdown',
 
     properties: {
       account: Object,
-      _hasAvatars: Boolean,
       links: {
         type: Array,
-        value: [
+        computed: '_getLinks(_switchAccountUrl)',
-          {name: 'Settings', url: '/settings'},
-          {name: 'Switch account', url: '/switch-account'},
-          {name: 'Sign out', url: '/logout'},
-        ],
       },
       topContent: {
         type: Array,
         computed: '_getTopContent(account)',
       },
+      _path: {
+        type: String,
+        value: '/',
+      },
+      _hasAvatars: Boolean,
+      _switchAccountUrl: String,
     },
 
     attached: function() {
+      this._handleLocationChange();
+      this.listen(window, 'location-change', '_handleLocationChange');
       this.$.restAPI.getConfig().then(function(cfg) {
+        if (cfg && cfg.auth && cfg.auth.switch_account_url) {
+          this._switchAccountUrl = cfg.auth.switch_account_url;
+        } else {
+          this._switchAccountUrl = null;
+        }
         this._hasAvatars = !!(cfg && cfg.plugin && cfg.plugin.has_avatars);
       }.bind(this));
     },
 
+    detached: function() {
+      this.unlisten(window, 'location-change', '_handleLocationChange');
+    },
+
+    _getLinks: function(switchAccountUrl) {
+      var links = [{name: 'Settings', url: '/settings'}];
+      if (switchAccountUrl) {
+        var replacements = {path: this._path};
+        var url = this._interpolateUrl(switchAccountUrl, replacements);
+        links.push({name: 'Switch account', url: url});
+      }
+      links.push({name: 'Sign out', url: '/logout'});
+      return links;
+    },
+
     _getTopContent: function(account) {
       return [
         {text: account.name, bold: true},
         {text: account.email},
       ];
     },
+
+    _handleLocationChange: function() {
+      this._path =
+          window.location.pathname +
+          window.location.search +
+          window.location.hash;
+    },
+
+    _interpolateUrl: function(url, replacements) {
+      return url.replace(INTERPOLATE_URL_PATTERN, function(match, p1) {
+        return replacements[p1] || '';
+      });
+    },
   });
 })();

polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown_test.html

@@ -46,5 +46,39 @@ limitations under the License.
       assert.deepEqual(element.topContent,
           [{text: 'John Doe', bold: true}, {text: 'john@doe.com'}]);
     });
+
+    test('switch account', function() {
+      // No switch account link.
+      assert.equal(element._getLinks(null).length, 2);
+
+      // Unparameterized switch account link.
+      var links = element._getLinks('/switch-account');
+      assert.equal(links.length, 3);
+      assert.deepEqual(links[1],
+          {name: 'Switch account', url: '/switch-account'});
+
+      // Parameterized switch account link.
+      element._path = '/c/123';
+      links = element._getLinks('/switch-account${path}');
+      assert.equal(links.length, 3);
+      assert.deepEqual(links[1],
+          {name: 'Switch account', url: '/switch-account/c/123'});
+    });
+
+    test('_interpolateUrl', function() {
+      var replacements = {
+        'foo': 'bar',
+        'test': 'TEST',
+      };
+      var interpolate = function(url) {
+        return element._interpolateUrl(url, replacements);
+      };
+
+      assert.equal(interpolate('test'), 'test');
+      assert.equal(interpolate('${test}'), 'TEST');
+      assert.equal(
+          interpolate('${}, ${test}, ${TEST}, ${foo}'),
+          '${}, TEST, , bar');
+    });
   });
 </script>