Merge "Change view update checks according to update_delay"

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js

@@ -27,6 +27,7 @@
   // Maximum length for patch set descriptions.
   var PATCH_DESC_MAX_LENGTH = 500;
   var REVIEWERS_REGEX = /^R=/gm;
+  var MIN_CHECK_INTERVAL_SECS = 0;
 
   Polymer({
     is: 'gr-change-view',
@@ -64,7 +65,10 @@
       },
       backPage: String,
       hasParent: Boolean,
-      serverConfig: Object,
+      serverConfig: {
+        type: Object,
+        observer: '_startUpdateCheckTimer',
+      },
       keyEventTarget: {
         type: Object,
         value: function() { return document.body; },
@@ -159,6 +163,7 @@
         type: Boolean,
         value: true,
       },
+      _updateCheckTimerHandle: Number,
     },
 
     behaviors: [
@@ -204,10 +209,16 @@
       this.addEventListener('editable-content-cancel',
           this._handleCommitMessageCancel.bind(this));
       this.listen(window, 'scroll', '_handleScroll');
+      this.listen(document, 'visibilitychange', '_handleVisibilityChange');
     },
 
     detached: function() {
       this.unlisten(window, 'scroll', '_handleScroll');
+      this.unlisten(document, 'visibilitychange', '_handleVisibilityChange');
+
+      if (this._updateCheckTimerHandle) {
+        this._cancelUpdateCheckTimer();
+      }
     },
 
     _handleEditCommitMessage: function(e) {
@@ -1154,5 +1165,46 @@
       return this._getScrollHeight(this.$.relatedChanges) <=
           this._getOffsetHeight(this.$.relatedChanges);
     },
+
+    _startUpdateCheckTimer: function() {
+      if (!this.serverConfig ||
+          !this.serverConfig.change ||
+          this.serverConfig.change.update_delay === undefined ||
+          this.serverConfig.change.update_delay <= MIN_CHECK_INTERVAL_SECS) {
+        return;
+      }
+
+      this._updateCheckTimerHandle = this.async(function() {
+        this.fetchIsLatestKnown(this._change, this.$.restAPI)
+            .then(function(latest) {
+              if (!latest) {
+                this._cancelUpdateCheckTimer();
+                this.fire('show-alert', {
+                  message: 'A newer patch has been uploaded.',
+                  action: 'Reload',
+                  callback: function() {
+                    // Load the current change without any patch range.
+                    location.href = this.getBaseUrl() + '/c/' +
+                        this._change._number;
+                  }.bind(this),
+                });
+              }
+              this._startUpdateCheckTimer();
+            }.bind(this));
+      }, this.serverConfig.change.update_delay * 1000);
+    },
+
+    _cancelUpdateCheckTimer: function() {
+      this.cancelAsync(this._updateCheckTimerHandle);
+      this._updateCheckTimerHandle = null;
+    },
+
+    _handleVisibilityChange: function() {
+      if (document.hidden && this._updateCheckTimerHandle) {
+        this._cancelUpdateCheckTimer();
+      } else if (!this._updateCheckTimerHandle) {
+        this._startUpdateCheckTimer();
+      }
+    },
   });
 })();

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html

@@ -1103,6 +1103,47 @@ limitations under the License.
         assert.equal(element.customStyle['--related-change-btn-top-padding'],
             '2px');
       });
+
+      suite('update checks', function() {
+        setup(function() {
+          sandbox.spy(element, '_startUpdateCheckTimer');
+          sandbox.stub(element, 'async', function(f) {
+            // Only fire the async callback one time.
+            if (element.async.callCount > 1) { return; }
+            f.call(element);
+          });
+        });
+
+        test('_startUpdateCheckTimer negative delay', function() {
+          sandbox.stub(element, 'fetchIsLatestKnown');
+
+          element.serverConfig = {change: {update_delay: -1}};
+
+          assert.isTrue(element._startUpdateCheckTimer.called);
+          assert.isFalse(element.fetchIsLatestKnown.called);
+        });
+
+        test('_startUpdateCheckTimer up-to-date', function() {
+          sandbox.stub(element, 'fetchIsLatestKnown',
+              function() { return Promise.resolve(true); });
+
+          element.serverConfig = {change: {update_delay: 12345}};
+
+          assert.isTrue(element._startUpdateCheckTimer.called);
+          assert.isTrue(element.fetchIsLatestKnown.called);
+          assert.equal(element.async.lastCall.args[1], 12345 * 1000);
+        });
+
+        test('_startUpdateCheckTimer out-of-date shows an alert',
+            function(done) {
+          sandbox.stub(element, 'fetchIsLatestKnown',
+              function() { return Promise.resolve(false); });
+          element.addEventListener('show-alert', function() {
+            done();
+          });
+          element.serverConfig = {change: {update_delay: 12345}};
+        });
+      });
     });
   });
 </script>