From 0000d6a7825666df6337822331d830cfbedb6d23 Mon Sep 17 00:00:00 2001
From: Emily Kager <emilykager@gmail.com>
Date: Sun, 5 May 2019 07:54:45 -0700
Subject: [PATCH] For #2277 - Clean up threading for session control with undo
 (#2281)

---
 .../org/mozilla/fenix/ext/CoroutineScope.kt   |  3 +-
 .../org/mozilla/fenix/home/HomeFragment.kt    | 33 +++++++++++++++----
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/app/src/main/java/org/mozilla/fenix/ext/CoroutineScope.kt b/app/src/main/java/org/mozilla/fenix/ext/CoroutineScope.kt
index 2859a501b..925feef3b 100644
--- a/app/src/main/java/org/mozilla/fenix/ext/CoroutineScope.kt
+++ b/app/src/main/java/org/mozilla/fenix/ext/CoroutineScope.kt
@@ -6,7 +6,6 @@ package org.mozilla.fenix.ext
 
 import android.view.View
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers.IO
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
@@ -19,7 +18,7 @@ fun CoroutineScope.allowUndo(
     onCancel: suspend () -> Unit = {},
     operation: suspend () -> Unit
 ) {
-    val undoJob = launch(IO) {
+    val undoJob = launch(Main) {
         delay(UNDO_DELAY)
         operation.invoke()
     }
diff --git a/app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt b/app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt
index e3ac40ab9..b588172c9 100644
--- a/app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt
+++ b/app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt
@@ -7,28 +7,28 @@ package org.mozilla.fenix.home
 import android.content.res.Resources
 import android.graphics.drawable.BitmapDrawable
 import android.os.Bundle
-import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.BOTTOM
-import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.TOP
-import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.START
-import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.END
-import androidx.constraintlayout.widget.ConstraintLayout.LayoutParams.PARENT_ID
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.appcompat.app.AppCompatActivity
+import androidx.constraintlayout.widget.ConstraintLayout.LayoutParams.PARENT_ID
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.ViewModelProviders
 import androidx.navigation.Navigation
 import kotlinx.android.synthetic.main.fragment_home.*
 import kotlinx.android.synthetic.main.fragment_home.view.*
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.runBlocking
 import mozilla.components.browser.menu.BrowserMenu
 import mozilla.components.browser.session.Session
 import mozilla.components.browser.session.SessionManager
+import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.BOTTOM
+import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.END
+import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.START
+import org.jetbrains.anko.constraint.layout.ConstraintSetBuilder.Side.TOP
 import org.jetbrains.anko.constraint.layout.applyConstraintSet
 import org.mozilla.fenix.BrowserDirection
 import org.mozilla.fenix.BrowsingModeManager
@@ -64,6 +64,9 @@ class HomeFragment : Fragment(), CoroutineScope {
     private val bus = ActionBusFactory.get(this)
     private var sessionObserver: SessionManager.Observer? = null
     private var homeMenu: HomeMenu? = null
+
+    var deleteSessionJob: (suspend () -> Unit)? = null
+
     private lateinit var sessionControlComponent: SessionControlComponent
 
     private lateinit var job: Job
@@ -203,7 +206,16 @@ class HomeFragment : Fragment(), CoroutineScope {
                 (activity as HomeActivity).openToBrowser(BrowserDirection.FromHome)
             }
             is TabAction.Close -> {
-                removeTabWithUndo(action.sessionId)
+                if (deleteSessionJob == null) removeTabWithUndo(action.sessionId) else {
+                    deleteSessionJob?.let {
+                        launch {
+                            it.invoke()
+                        }.invokeOnCompletion {
+                            deleteSessionJob = null
+                            removeTabWithUndo(action.sessionId)
+                        }
+                    }
+                }
             }
             is TabAction.Share -> {
                 requireComponents.core.sessionManager.findSessionById(action.sessionId)
@@ -323,6 +335,13 @@ class HomeFragment : Fragment(), CoroutineScope {
             )
         )
 
+        deleteSessionJob = {
+            sessionManager.findSessionById(sessionId)
+                ?.let { session ->
+                    sessionManager.remove(session)
+                }
+        }
+
         CoroutineScope(Dispatchers.Main).allowUndo(
             view!!, getString(R.string.snackbar_tab_deleted),
             getString(R.string.snackbar_deleted_undo), { emitSessionChanges() }