installModes: implement new ON_NEXT_SUSPEND install mode (#770)

Restart the app _while_ it is in the background, but only after it has been in the background for "minimumBackgroundDuration" seconds (0 by default), so that user context isn't lost unless the app suspension is long enough to not matter.

Author: sergey-akhalkov

CodePush.js

@@ -497,7 +497,10 @@ if (NativeCodePush) {
     InstallMode: {
       IMMEDIATE: NativeCodePush.codePushInstallModeImmediate, // Restart the app immediately
       ON_NEXT_RESTART: NativeCodePush.codePushInstallModeOnNextRestart, // Don't artificially restart the app. Allow the update to be "picked up" on the next app restart
-      ON_NEXT_RESUME: NativeCodePush.codePushInstallModeOnNextResume // Restart the app the next time it is resumed from the background
+      ON_NEXT_RESUME: NativeCodePush.codePushInstallModeOnNextResume, // Restart the app the next time it is resumed from the background
+      ON_NEXT_SUSPEND: NativeCodePush.codePushInstallModeOnNextSuspend // Restart the app _while_ it is in the background,
+      // but only after it has been in the background for "minimumBackgroundDuration" seconds (0 by default),
+      // so that user context isn't lost unless the app suspension is long enough to not matter
     },
     SyncStatus: {
       UP_TO_DATE: 0, // The running app is up-to-date

android/app/src/main/java/com/microsoft/codepush/react/CodePushInstallMode.java

@@ -3,7 +3,8 @@
 public enum CodePushInstallMode {
     IMMEDIATE(0),
     ON_NEXT_RESTART(1),
-    ON_NEXT_RESUME(2);
+    ON_NEXT_RESUME(2),
+    ON_NEXT_SUSPEND(3);
 
     private final int value;
     CodePushInstallMode(int value) {

android/app/src/main/java/com/microsoft/codepush/react/CodePushNativeModule.java

@@ -67,6 +67,7 @@ public Map<String, Object> getConstants() {
         constants.put("codePushInstallModeImmediate", CodePushInstallMode.IMMEDIATE.getValue());
         constants.put("codePushInstallModeOnNextRestart", CodePushInstallMode.ON_NEXT_RESTART.getValue());
         constants.put("codePushInstallModeOnNextResume", CodePushInstallMode.ON_NEXT_RESUME.getValue());
+        constants.put("codePushInstallModeOnNextSuspend", CodePushInstallMode.ON_NEXT_SUSPEND.getValue());
 
         constants.put("codePushUpdateStateRunning", CodePushUpdateState.RUNNING.getValue());
         constants.put("codePushUpdateStatePending", CodePushUpdateState.PENDING.getValue());
@@ -438,7 +439,8 @@ protected Void doInBackground(Void... params) {
                     // We also add the resume listener if the installMode is IMMEDIATE, because
                     // if the current activity is backgrounded, we want to reload the bundle when
                     // it comes back into the foreground.
-                    installMode == CodePushInstallMode.IMMEDIATE.getValue()) {
+                    installMode == CodePushInstallMode.IMMEDIATE.getValue() ||
+                    installMode == CodePushInstallMode.ON_NEXT_SUSPEND.getValue()) {
 
                     // Store the minimum duration on the native module as an instance
                     // variable instead of relying on a closure below, so that any
@@ -449,9 +451,18 @@ protected Void doInBackground(Void... params) {
                         // Ensure we do not add the listener twice.
                         mLifecycleEventListener = new LifecycleEventListener() {
                             private Date lastPausedDate = null;
+                            private Handler appSuspendHandler = new Handler(Looper.getMainLooper());
+                            private Runnable loadBundleRunnable = new Runnable() {
+                                @Override
+                                public void run() {
+                                    CodePushUtils.log("Loading bundle on suspend");
+                                    loadBundle();
+                                }
+                            };
 
                             @Override
                             public void onHostResume() {
+                                appSuspendHandler.removeCallbacks(loadBundleRunnable);
                                 // As of RN 36, the resume handler fires immediately if the app is in
                                 // the foreground, so explicitly wait for it to be backgrounded first
                                 if (lastPausedDate != null) {
@@ -469,6 +480,10 @@ public void onHostPause() {
                                 // Save the current time so that when the app is later
                                 // resumed, we can detect how long it was in the background.
                                 lastPausedDate = new Date();
+
+                                if (installMode == CodePushInstallMode.ON_NEXT_SUSPEND.getValue() && mSettingsManager.isPendingUpdate(null)) {
+                                    appSuspendHandler.postDelayed(loadBundleRunnable, minimumBackgroundDuration * 1000);
+                                }
                             }
 
                             @Override

ios/CodePush/CodePush.h

@@ -187,7 +187,8 @@ void CPLog(NSString *formatString, ...);
 typedef NS_ENUM(NSInteger, CodePushInstallMode) {
     CodePushInstallModeImmediate,
     CodePushInstallModeOnNextRestart,
-    CodePushInstallModeOnNextResume
+    CodePushInstallModeOnNextResume,
+    CodePushInstallModeOnNextSuspend
 };
 
 typedef NS_ENUM(NSInteger, CodePushUpdateState) {

ios/CodePush/CodePush.m

@@ -24,6 +24,8 @@ @implementation CodePush {
     BOOL _isFirstRunAfterUpdate;
     int _minimumBackgroundDuration;
     NSDate *_lastResignedDate;
+    CodePushInstallMode *_installMode;
+    NSTimer *_appSuspendTimer;
 
     // Used to coordinate the dispatching of download progress events to JS.
     long long _latestExpectedContentLength;
@@ -292,6 +294,7 @@ - (NSDictionary *)constantsToExport
              @"codePushInstallModeOnNextRestart":@(CodePushInstallModeOnNextRestart),
              @"codePushInstallModeImmediate": @(CodePushInstallModeImmediate),
              @"codePushInstallModeOnNextResume": @(CodePushInstallModeOnNextResume),
+             @"codePushInstallModeOnNextSuspend": @(CodePushInstallModeOnNextSuspend),
 
              @"codePushUpdateStateRunning": @(CodePushUpdateStateRunning),
              @"codePushUpdateStatePending": @(CodePushUpdateStatePending),
@@ -559,6 +562,10 @@ - (void)savePendingUpdate:(NSString *)packageHash
 // a resume-based update still pending installation.
 - (void)applicationWillEnterForeground
 {
+    if (_appSuspendTimer) {
+        [_appSuspendTimer invalidate];
+        _appSuspendTimer = nil;
+    }
     // Determine how long the app was in the background and ensure
     // that it meets the minimum duration amount of time.
     int durationInBackground = 0;
@@ -576,6 +583,18 @@ - (void)applicationWillResignActive
     // Save the current time so that when the app is later
     // resumed, we can detect how long it was in the background.
     _lastResignedDate = [NSDate date];
+    
+    if (_installMode == CodePushInstallModeOnNextSuspend && [[self class] isPendingUpdate:nil]) {
+        _appSuspendTimer = [NSTimer scheduledTimerWithTimeInterval:_minimumBackgroundDuration
+                                                         target:self
+                                                       selector:@selector(loadBundleOnTick:)
+                                                       userInfo:nil
+                                                        repeats:NO];
+    }
+}
+
+-(void)loadBundleOnTick:(NSTimer *)timer {
+    [self loadBundle];
 }
 
 #pragma mark - JavaScript-exported module methods (Public)
@@ -749,7 +768,8 @@ - (void)applicationWillResignActive
         [self savePendingUpdate:updatePackage[PackageHashKey]
                       isLoading:NO];
 
-        if (installMode == CodePushInstallModeOnNextResume) {
+        _installMode = installMode;
+        if (_installMode == CodePushInstallModeOnNextResume || _installMode == CodePushInstallModeOnNextSuspend) {
             _minimumBackgroundDuration = minimumBackgroundDuration;
 
             if (!_hasResumeListener) {

ios/CodePush/RCTConvert+CodePushInstallMode.m

@@ -12,7 +12,8 @@ @implementation RCTConvert (CodePushInstallMode)
 
 RCT_ENUM_CONVERTER(CodePushInstallMode, (@{ @"codePushInstallModeImmediate": @(CodePushInstallModeImmediate),
                                             @"codePushInstallModeOnNextRestart": @(CodePushInstallModeOnNextRestart),
-                                            @"codePushInstallModeOnNextResume": @(CodePushInstallModeOnNextResume) }),
+                                            @"codePushInstallModeOnNextResume": @(CodePushInstallModeOnNextResume),
+                                            @"codePushInstallModeOnNextSuspend": @(CodePushInstallModeOnNextSuspend) }),
                    CodePushInstallModeImmediate, // Default enum value
                    integerValue)