From 35201d16404fffa28361793400b0fb82637f20bf Mon Sep 17 00:00:00 2001
From: Geoffrey Goh <kg422@cornell.edu>
Date: Fri, 5 Feb 2016 15:52:25 -0800
Subject: [PATCH] cache sync calls

---
 CodePush.js                                   | 16 ++++++++++++++--
 CodePushPackage.m                             |  2 +-
 Examples/CodePushDemoApp/crossplatformdemo.js | 16 +++++++++++-----
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/CodePush.js b/CodePush.js
index 5072db6..e3c726d 100644
--- a/CodePush.js
+++ b/CodePush.js
@@ -170,8 +170,20 @@ function setUpTestDependencies(testSdk, providedTestConfig, testNativeBridge) {
   if (testNativeBridge) NativeCodePush = testNativeBridge;
 }
 
+// This function allows sync operations to be chained on to each other so that they do not
+// interleave in the event that sync() is called multiple times.
+const sync = (() => {
+  let syncPromiseChain = Promise.resolve();
+  return (options = {}, syncStatusChangeCallback, downloadProgressCallback) => {
+    syncPromiseChain = syncPromiseChain
+      .catch(() => {})
+      .then(() => syncOperation(options, syncStatusChangeCallback, downloadProgressCallback));
+    return syncPromiseChain;
+  };
+})();
+
 /*
- * The sync method provides a simple, one-line experience for
+ * The syncOperation method provides a simple, one-line experience for
  * incorporating the check, download and application of an update.
  * 
  * It simply composes the existing API methods together and adds additional
@@ -179,7 +191,7 @@ function setUpTestDependencies(testSdk, providedTestConfig, testNativeBridge) {
  * releases, and displaying a standard confirmation UI to the end-user
  * when an update is available.
  */
-async function sync(options = {}, syncStatusChangeCallback, downloadProgressCallback) {  
+async function syncOperation(options = {}, syncStatusChangeCallback, downloadProgressCallback) {  
   const syncOptions = {
     
     deploymentKey: null,
diff --git a/CodePushPackage.m b/CodePushPackage.m
index 888c080..20ed64a 100644
--- a/CodePushPackage.m
+++ b/CodePushPackage.m
@@ -449,7 +449,7 @@ NSString * const UnzippedFolderName = @"unzipped";
 }
 
 + (void)installPackage:(NSDictionary *)updatePackage
-               error:(NSError **)error
+                 error:(NSError **)error
 {
     NSString *packageHash = updatePackage[@"packageHash"];
     NSMutableDictionary *info = [self getCurrentPackageInfo:error];
diff --git a/Examples/CodePushDemoApp/crossplatformdemo.js b/Examples/CodePushDemoApp/crossplatformdemo.js
index d941af0..642165a 100644
--- a/Examples/CodePushDemoApp/crossplatformdemo.js
+++ b/Examples/CodePushDemoApp/crossplatformdemo.js
@@ -92,16 +92,22 @@ let CodePushDemoApp = React.createClass({
   render() {
     let syncView, syncButton, progressView;
     
-    if (this.state.syncMessage) {
-      syncView = (
-        <Text style={styles.messages}>{this.state.syncMessage}</Text>
-      );
-    } else {
       syncButton = ( 
         <Button style={{color: 'green'}} onPress={this.sync}>
           Start Sync!
         </Button>
       );
+      
+    if (this.state.syncMessage) {
+      syncView = (
+        <Text style={styles.messages}>{this.state.syncMessage}</Text>
+      );
+    } else {
+      /*syncButton = ( 
+        <Button style={{color: 'green'}} onPress={this.sync}>
+          Start Sync!
+        </Button>
+      );*/
     }
     
     if (this.state.progress) {