Make restarted-demo track multiple open windows and restore them on r…

…estart.

restarted-demo/README.md

@@ -2,7 +2,7 @@
 
 When an app is restored after being unexpectedly terminated (eg, when the browser restarts) it will be sent an onRestarted event which should restore the app to the state it was in when it was last running.
 
-This demo app contains a counter which is reset when the app is launched, but preserved across app restarts.
+This demo app creates a new counter on launch and restores any existing counters across app restarts.
 
 
 ## APIs

restarted-demo/background.js

@@ -1,24 +1,135 @@
-function runApp(startedBy, data) {
+// All the counters.
+Counter.all = [];
+
+function Counter(id, clicks, startedBy) {
+  this.id = id;
+  this.clicks = clicks;
+  this.startedBy = startedBy;
+  this.saving = false;
+  this.listeners = [];
+  this.save();
+  Counter.all.push(this);
+}
+
+Counter.prototype.attachToWindow = function(win, document) {
+  win.onClosed.addListener(this.close.bind(this));
+
+  var self = this;
+  document.getElementById('started-by').innerText = this.startedBy;
+  this.addListener(function(clicks) {
+    document.getElementById('number').innerText = clicks;
+  });
+
+  document.getElementById('clickButton').addEventListener('click', function(e) {
+    self.increment();
+  }, false);
+
+  document.getElementById('logLocalStorage').addEventListener('click', function(e) {
+    logLocalStorage();
+  }, false);
+};
+
+Counter.prototype.addListener = function(l) {
+  this.listeners.push(l);
+  this.notifyClickCount();
+};
+
+Counter.prototype.clearListeners = function() {
+  this.listeners = [];
+};
+
+Counter.prototype.notifyClickCount = function() {
+  for (var i = 0; i < this.listeners.length; i++) {
+    this.listeners[i](this.clicks);
+  }
+};
+
+Counter.prototype.increment = function() {
+  this.clicks++;
+  this.notifyClickCount();
+  this.save();
+};
+
+Counter.prototype.save = function() {
+  if (this.saving)
+    return;
+
+  this.saving = true;
+
+  var self = this;
+  (function(clicks) {
+    var counters = {};
+    counters[self.id] = {'clicks': clicks};
+    var data = {'counters': counters};
+    chrome.storage.local.get('counters', function(data) {
+      if (!data.counters) {
+        data.counters = {};
+      }
+      data.counters[self.id] = {'clicks': clicks};
+      chrome.storage.local.set(data, function() {
+        self.saving = false;
+        if (self.clicks != clicks) {
+          // self.clicks changed while we were saving, so save again.
+          self.save();
+        }
+      });
+    });
+  })(this.clicks);
+};
+
+Counter.prototype.close = function() {
+  this.clearListeners();
+  var self = this;
+  chrome.storage.local.get('counters', function(data) {
+    delete data.counters[self.id];
+    chrome.storage.local.set(data);
+  });
+
+  // Remove self from global list.
+  var i = Counter.all.indexOf(this);
+  if (i != -1)
+    Counter.splice(i, 1);
+};
+
+function runApp(counter) {
   chrome.app.window.create('main.html', {
+    id: counter.id + '',
     width: 800,
     height: 600
   }, function(win) {
     win.contentWindow.onload = function() {
-      win.contentWindow.setStartedBy(startedBy);
-      win.contentWindow.updateData(data);
+      counter.attachToWindow(win, win.contentWindow.document);
     };
   });
 }
 
 chrome.app.runtime.onLaunched.addListener(function() {
-  var data = {'clicks': 0};
-  chrome.storage.local.set(data, function() {
-    runApp('launched', data);
+  if (Counter.all.length == 0) {
+    // We might have left over state from a previous hard shutdown.
+    chrome.storage.local.clear();
+  }
+  chrome.storage.local.get('nextId', function(data) {
+    if (!data.nextId)
+      data.nextId = 0;
+    var id = data.nextId++;
+    var counter = new Counter(id, 0, 'launched');
+    runApp(counter);
+    chrome.storage.local.set(data);
   });
 });
 
 chrome.app.runtime.onRestarted.addListener(function() {
-  chrome.storage.local.get('clicks', function(data) {
-    runApp('restarted', data);
+  chrome.storage.local.get(null, function(data) {
+    for (var id in data.counters) {
+      var clicks = data.counters[id].clicks;
+      var counter = new Counter(id, clicks, 'restarted');
+      runApp(counter);
+    }
   });
 });
+
+function logLocalStorage() {
+  chrome.storage.local.get(null, function(data) {
+    console.log("local storage:", data);
+  });
+}

restarted-demo/main.html

@@ -10,6 +10,6 @@
     <td>Clicks</td><td id='number'></td>
   </tr>
 </table>
-<input id='button' type='submit' value='Click'></input>
+<input id='clickButton' type='submit' value='Click'></input>
+<input id='logLocalStorage' type='submit' value='Log local storage'></input>
 </body>
-<script src='main.js'></script>