From 0f18fc1c269a065b9c3a70d678a0961ef1c00e3f Mon Sep 17 00:00:00 2001
From: Joseph Schorr <joseph.schorr@coreos.com>
Date: Thu, 21 May 2015 17:16:38 -0400
Subject: [PATCH] Disable the angular poll channel when the browser tab is
 hidden

Quay pages that normally poll (repo view, build logs, etc) will skip the API call(s) when the tab is hidden.
---
 static/js/services/angular-poll-channel.js    |  9 ++-
 .../services/document-visibility-service.js   | 60 +++++++++++++++++++
 2 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 static/js/services/document-visibility-service.js

diff --git a/static/js/services/angular-poll-channel.js b/static/js/services/angular-poll-channel.js
index adba49757..f4028a65f 100644
--- a/static/js/services/angular-poll-channel.js
+++ b/static/js/services/angular-poll-channel.js
@@ -1,7 +1,8 @@
 /**
  * Specialized class for conducting an HTTP poll, while properly preventing multiple calls.
  */
-angular.module('quay').factory('AngularPollChannel', ['ApiService', '$timeout', function(ApiService, $timeout) {
+angular.module('quay').factory('AngularPollChannel', ['ApiService', '$timeout', 'DocumentVisibilityService',
+    function(ApiService, $timeout, DocumentVisibilityService) {
   var _PollChannel = function(scope, requester, opt_sleeptime) {
     this.scope_ = scope;
     this.requester_ = requester;
@@ -50,6 +51,12 @@ angular.module('quay').factory('AngularPollChannel', ['ApiService', '$timeout',
   _PollChannel.prototype.call_ = function() {
     if (this.working) { return; }
 
+    // If the document is currently hidden, skip the call.
+    if (DocumentVisibilityService.isHidden()) {
+      this.setupTimer_();
+      return;
+    }
+
     var that = this;
     this.working = true;
     this.scope_.$apply(function() {
diff --git a/static/js/services/document-visibility-service.js b/static/js/services/document-visibility-service.js
new file mode 100644
index 000000000..f56ecc633
--- /dev/null
+++ b/static/js/services/document-visibility-service.js
@@ -0,0 +1,60 @@
+/**
+ * Helper service which fires off events when the document's visibility changes, as well as allowing
+ * other Angular code to query the state of the document's visibility directly.
+ */
+angular.module('quay').constant('CORE_EVENT', {
+  DOC_VISIBILITY_CHANGE: 'core.event.doc_visibility_change'
+});
+
+angular.module('quay').factory('DocumentVisibilityService', ['$rootScope', '$document', 'CORE_EVENT',
+    function($rootScope, $document, CORE_EVENT) {
+  var document = $document[0],
+  features,
+  detectedFeature;
+
+  function broadcastChangeEvent() {
+    $rootScope.$broadcast(CORE_EVENT.DOC_VISIBILITY_CHANGE,
+                          document[detectedFeature.propertyName]);
+  }
+
+  features = {
+    standard: {
+      eventName: 'visibilitychange',
+      propertyName: 'hidden'
+    },
+    moz: {
+      eventName: 'mozvisibilitychange',
+      propertyName: 'mozHidden'
+    },
+    ms: {
+      eventName: 'msvisibilitychange',
+      propertyName: 'msHidden'
+    },
+    webkit: {
+      eventName: 'webkitvisibilitychange',
+      propertyName: 'webkitHidden'
+    }
+  };
+
+  Object.keys(features).some(function(feature) {
+    if (document[features[feature].propertyName] !== undefined) {
+      detectedFeature = features[feature];
+      return true;
+    }
+  });
+
+  if (detectedFeature) {
+    $document.on(detectedFeature.eventName, broadcastChangeEvent);
+  }
+
+  return {
+    /**
+     * Is the window currently hidden or not.
+     */
+    isHidden: function() {
+      if (detectedFeature) {
+        return document[detectedFeature.propertyName];
+      }
+    }
+  };
+}]);
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