ui: allow vetoing tunnel selection changes

These changes can happen at the wrong time, so we need to be able to
walk them back. Fixes:

Exception java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
  at androidx.fragment.app.FragmentManager.checkStateLoss (FragmentManager.java:1610)
  at androidx.fragment.app.FragmentManager.enqueueAction (FragmentManager.java:1650)
  at androidx.fragment.app.BackStackRecord.commitInternal (BackStackRecord.java:341)
  at androidx.fragment.app.BackStackRecord.commit (BackStackRecord.java:306)
  at androidx.fragment.app.FragmentManagerKt.commit$default (FragmentManager.kt:35)
  at com.wireguard.android.activity.MainActivity.onSelectedTunnelChanged (MainActivity.kt:113)
  at com.wireguard.android.activity.BaseActivity.setSelectedTunnel (BaseActivity.kt:25)
  at com.wireguard.android.activity.BaseActivity$onCreate$1.invokeSuspend (BaseActivity.kt:44)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.internal.DispatchedContinuation.resumeUndispatchedWith (DispatchedContinuation.java:256)
  at kotlinx.coroutines.DispatchedTaskKt.resume (DispatchedTask.kt:177)
  at kotlinx.coroutines.CancellableContinuationImpl.parentCancelled$kotlinx_coroutines_core (CancellableContinuationImpl.kt:190)
  at kotlinx.coroutines.DispatchedTaskKt.resumeUnconfined (DispatchedTask.kt:190)
  at kotlinx.coroutines.DispatchedTaskKt.dispatch (DispatchedTask.kt:161)
  at kotlinx.coroutines.CancellableContinuationImpl.dispatchResume (CancellableContinuationImpl.kt:397)
  at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl (CancellableContinuationImpl.kt:431)
  at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl$default (CancellableContinuationImpl.kt:420)
  at kotlinx.coroutines.CancellableContinuationImpl.resumeWith (CancellableContinuationImpl.kt:328)
  at kotlinx.coroutines.ResumeAwaitOnCompletion.invoke (JobSupport.kt:1413)
  at kotlinx.coroutines.JobSupport.notifyHandlers (JobSupport.kt:368)
  at kotlinx.coroutines.JobSupport.notifyCompletion (JobSupport.kt:362)
  at kotlinx.coroutines.JobSupport.completeStateFinalization (JobSupport.kt:323)
  at kotlinx.coroutines.JobSupport.finalizeFinishingState (JobSupport.kt:240)
  at kotlinx.coroutines.JobSupport.tryMakeCompletingSlowPath (JobSupport.kt:906)
  at kotlinx.coroutines.JobSupport.tryMakeCompleting (JobSupport.kt:863)
  at kotlinx.coroutines.JobSupport.makeCompleting$kotlinx_coroutines_core (JobSupport.kt:806)
  at kotlinx.coroutines.CompletableDeferredImpl.complete (CompletableDeferredImpl.java:92)
  at com.wireguard.android.model.TunnelManager$onTunnelsLoaded$1.invokeSuspend (TunnelManager.kt:120)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:106)
  at android.os.Handler.handleCallback (Handler.java:938)
  at android.os.Handler.dispatchMessage (Handler.java:99)
  at android.os.Looper.loop (Looper.java:237)
  at android.app.ActivityThread.main (ActivityThread.java:8163)
  at java.lang.reflect.Method.invoke
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:656)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:967)

Exception java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
  at androidx.fragment.app.FragmentManager.checkStateLoss (FragmentManager.java:1610)
  at androidx.fragment.app.FragmentManager.enqueueAction (FragmentManager.java:1650)
  at androidx.fragment.app.BackStackRecord.commitInternal (BackStackRecord.java:341)
  at androidx.fragment.app.BackStackRecord.commit (BackStackRecord.java:306)
  at androidx.fragment.app.FragmentManagerKt.commit$default (FragmentManager.kt:35)
  at com.wireguard.android.activity.MainActivity.onSelectedTunnelChanged (MainActivity.kt:113)
  at com.wireguard.android.activity.BaseActivity.setSelectedTunnel (BaseActivity.kt:25)
  at com.wireguard.android.activity.BaseActivity$onCreate$1.invokeSuspend (BaseActivity.kt:44)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.internal.DispatchedContinuation.resumeUndispatchedWith (DispatchedContinuation.java:256)
  at kotlinx.coroutines.DispatchedTaskKt.resume (DispatchedTask.kt:177)
  at kotlinx.coroutines.CancellableContinuationImpl.parentCancelled$kotlinx_coroutines_core (CancellableContinuationImpl.kt:190)
  at kotlinx.coroutines.DispatchedTaskKt.resumeUnconfined (DispatchedTask.kt:190)
  at kotlinx.coroutines.DispatchedTaskKt.dispatch (DispatchedTask.kt:161)
  at kotlinx.coroutines.CancellableContinuationImpl.dispatchResume (CancellableContinuationImpl.kt:397)
  at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl (CancellableContinuationImpl.kt:431)
  at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl$default (CancellableContinuationImpl.kt:420)
  at kotlinx.coroutines.CancellableContinuationImpl.resumeWith (CancellableContinuationImpl.kt:328)
  at kotlinx.coroutines.ResumeAwaitOnCompletion.invoke (JobSupport.kt:1413)
  at kotlinx.coroutines.JobSupport.notifyHandlers (JobSupport.kt:368)
  at kotlinx.coroutines.JobSupport.notifyCompletion (JobSupport.kt:362)
  at kotlinx.coroutines.JobSupport.completeStateFinalization (JobSupport.kt:323)
  at kotlinx.coroutines.JobSupport.finalizeFinishingState (JobSupport.kt:240)
  at kotlinx.coroutines.JobSupport.tryMakeCompletingSlowPath (JobSupport.kt:906)
  at kotlinx.coroutines.JobSupport.tryMakeCompleting (JobSupport.kt:863)
  at kotlinx.coroutines.JobSupport.makeCompleting$kotlinx_coroutines_core (JobSupport.kt:806)
  at kotlinx.coroutines.CompletableDeferredImpl.complete (CompletableDeferredImpl.java:92)
  at com.wireguard.android.model.TunnelManager$onTunnelsLoaded$1.invokeSuspend (TunnelManager.kt:120)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:106)
  at android.os.Handler.handleCallback (Handler.java:938)
  at android.os.Handler.dispatchMessage (Handler.java:99)
  at android.os.Looper.loopOnce (Looper.java:210)
  at android.os.Looper.loop (Looper.java:299)
  at android.app.ActivityThread.main (ActivityThread.java:8302)
  at java.lang.reflect.Method.invoke
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:556)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1037)

Exception java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
  at androidx.fragment.app.FragmentManager.checkStateLoss (FragmentManager.java:1610)
  at androidx.fragment.app.FragmentManager.ensureExecReady (FragmentManager.java:1711)
  at androidx.fragment.app.FragmentManager.execPendingActions (FragmentManager.java:1754)
  at androidx.fragment.app.FragmentManager.popBackStackImmediate (FragmentManager.java:854)
  at androidx.fragment.app.FragmentManager.popBackStackImmediate (FragmentManager.java:778)
  at com.wireguard.android.activity.MainActivity.onSelectedTunnelChanged (MainActivity.kt:110)
  at com.wireguard.android.activity.BaseActivity.setSelectedTunnel (BaseActivity.kt:25)
  at com.wireguard.android.activity.BaseActivity$onCreate$1.invokeSuspend (BaseActivity.kt:44)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:106)
  at kotlinx.coroutines.EventLoop.processUnconfinedEvent (EventLoop.common.kt:69)
  at kotlinx.coroutines.DispatchedTaskKt.runUnconfinedEventLoop (DispatchedTask.kt:204)
  at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith (DispatchedContinuation.kt:282)
  at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable (Cancellable.kt:30)
  at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable$default (Cancellable.kt:25)
  at kotlinx.coroutines.CoroutineStart.invoke (CoroutineStart.java:110)
  at kotlinx.coroutines.AbstractCoroutine.start (AbstractCoroutine.kt:126)
  at kotlinx.coroutines.BuildersKt.launch$default (Builders.kt)
  at com.wireguard.android.model.TunnelManager.onTunnelsLoaded (TunnelManager.java:114)
  at com.wireguard.android.model.TunnelManager.access$onTunnelsLoaded (TunnelManager.java:40)
  at com.wireguard.android.model.TunnelManager$onCreate$1.invokeSuspend (TunnelManager.kt:104)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
  at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:106)
  at android.os.Handler.handleCallback (Handler.java:942)
  at android.os.Handler.dispatchMessage (Handler.java:99)
  at android.os.Looper.loopOnce (Looper.java:226)
  at android.os.Looper.loop (Looper.java:313)
  at android.app.ActivityThread.main (ActivityThread.java:8757)
  at java.lang.reflect.Method.invoke
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:571)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1067)

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

3 files changed, 15 insertions, 6 deletions

diff --git a/ui/src/main/java/com/wireguard/android/activity/BaseActivity.kt b/ui/src/main/java/com/wireguard/android/activity/BaseActivity.kt
index bec673db..cfd34e42 100644
--- a/ui/src/main/java/com/wireguard/android/activity/BaseActivity.kt
+++ b/ui/src/main/java/com/wireguard/android/activity/BaseActivity.kt
@@ -25,8 +25,11 @@ abstract class BaseActivity : AppCompatActivity() {
             if (oldTunnel == value) return
             field = value
             if (created) {
-                onSelectedTunnelChanged(oldTunnel, value)
-                selectionChangeRegistry.notifyCallbacks(oldTunnel, 0, value)
+                if (!onSelectedTunnelChanged(oldTunnel, value)) {
+                    field = oldTunnel
+                } else {
+                    selectionChangeRegistry.notifyCallbacks(oldTunnel, 0, value)
+                }
             }
         }
 
@@ -61,7 +64,7 @@ abstract class BaseActivity : AppCompatActivity() {
         super.onSaveInstanceState(outState)
     }
 
-    protected abstract fun onSelectedTunnelChanged(oldTunnel: ObservableTunnel?, newTunnel: ObservableTunnel?)
+    protected abstract fun onSelectedTunnelChanged(oldTunnel: ObservableTunnel?, newTunnel: ObservableTunnel?): Boolean
 
     fun removeOnSelectedTunnelChangedListener(
             listener: OnSelectedTunnelChangedListener) {
diff --git a/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt b/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt
index 1566c129..b6c67e88 100644
--- a/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt
+++ b/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt
@@ -96,13 +96,17 @@ class MainActivity : BaseActivity(), FragmentManager.OnBackStackChangedListener
     }
 
     override fun onSelectedTunnelChanged(oldTunnel: ObservableTunnel?,
-                                         newTunnel: ObservableTunnel?) {
+                                         newTunnel: ObservableTunnel?): Boolean {
         val fragmentManager = supportFragmentManager
+        if (fragmentManager.isStateSaved) {
+            return false
+        }
+
         val backStackEntries = fragmentManager.backStackEntryCount
         if (newTunnel == null) {
             // Clear everything off the back stack (all editors and detail fragments).
             fragmentManager.popBackStackImmediate(0, FragmentManager.POP_BACK_STACK_INCLUSIVE)
-            return
+            return true
         }
         if (backStackEntries == 2) {
             // Pop the editor off the back stack to reveal the detail fragment. Use the immediate
@@ -116,5 +120,6 @@ class MainActivity : BaseActivity(), FragmentManager.OnBackStackChangedListener
                 addToBackStack(null)
             }
         }
+        return true
     }
 }
diff --git a/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.kt b/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.kt
index b3fccee3..bdf798ca 100644
--- a/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.kt
+++ b/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.kt
@@ -22,7 +22,8 @@ class TunnelCreatorActivity : BaseActivity() {
         }
     }
 
-    override fun onSelectedTunnelChanged(oldTunnel: ObservableTunnel?, newTunnel: ObservableTunnel?) {
+    override fun onSelectedTunnelChanged(oldTunnel: ObservableTunnel?, newTunnel: ObservableTunnel?): Boolean {
         finish()
+        return true
     }
 }