From a0ecff9a3d3ae583ea87e687b2b4174b8a790c8d Mon Sep 17 00:00:00 2001
From: Alex Baker <alex@tasks.org>
Date: Thu, 30 Dec 2021 13:35:01 -0600
Subject: [PATCH] Replace flow with channel

---
 .../astrid/adapter/NavigationDrawerAdapter.kt |  4 +-
 .../org/tasks/activities/DragAndDropDiffer.kt | 37 +++++++++++--------
 .../tasklist/DragAndDropRecyclerAdapter.kt    |  4 +-
 3 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/app/src/main/java/com/todoroo/astrid/adapter/NavigationDrawerAdapter.kt b/app/src/main/java/com/todoroo/astrid/adapter/NavigationDrawerAdapter.kt
index 27ff8a22b..d3e530886 100644
--- a/app/src/main/java/com/todoroo/astrid/adapter/NavigationDrawerAdapter.kt
+++ b/app/src/main/java/com/todoroo/astrid/adapter/NavigationDrawerAdapter.kt
@@ -17,7 +17,7 @@ import com.todoroo.astrid.api.FilterListItem
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.asCoroutineDispatcher
-import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.channels.Channel
 import org.tasks.LocalBroadcastManager
 import org.tasks.activities.DragAndDropDiffer
 import org.tasks.billing.Inventory
@@ -45,7 +45,7 @@ class NavigationDrawerAdapter @Inject constructor(
 
     private lateinit var onClick: (FilterListItem?) -> Unit
     private var selected: Filter? = null
-    override val flow = MutableSharedFlow<MutableList<FilterListItem>>()
+    override val channel = Channel<List<FilterListItem>>(Channel.UNLIMITED)
     override val updates: Queue<Pair<MutableList<FilterListItem>, DiffUtil.DiffResult?>> = LinkedList()
     override val scope: CoroutineScope =
         CoroutineScope(Executors.newSingleThreadExecutor().asCoroutineDispatcher() + Job())
diff --git a/app/src/main/java/org/tasks/activities/DragAndDropDiffer.kt b/app/src/main/java/org/tasks/activities/DragAndDropDiffer.kt
index bbd718f7b..7e7965524 100644
--- a/app/src/main/java/org/tasks/activities/DragAndDropDiffer.kt
+++ b/app/src/main/java/org/tasks/activities/DragAndDropDiffer.kt
@@ -3,23 +3,30 @@ package org.tasks.activities
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListUpdateCallback
 import com.todoroo.andlib.utility.AndroidUtilities
-import kotlinx.coroutines.*
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.consumeAsFlow
+import kotlinx.coroutines.flow.drop
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.scan
 import java.util.*
-import java.util.concurrent.Executors
 
 interface DragAndDropDiffer<T, R> : ListUpdateCallback {
-    val flow: MutableSharedFlow<R>
+    val channel: Channel<List<T>>
     val updates: Queue<Pair<R, DiffUtil.DiffResult?>>
     var items: R
     var dragging: Boolean
     val scope: CoroutineScope
 
     fun submitList(list: List<T>) {
-        scope.launch {
-            val transform = transform(list)
-            flow.emit(transform)
-        }
+        channel.trySend(list)
     }
 
     fun calculateDiff(last: Pair<R, DiffUtil.DiffResult?>, next: R): Pair<R, DiffUtil.DiffResult?> {
@@ -48,18 +55,16 @@ interface DragAndDropDiffer<T, R> : ListUpdateCallback {
     @ExperimentalCoroutinesApi
     fun initializeDiffer(list: List<T>): R {
         val initial = transform(list)
-        flow
+        channel
+            .consumeAsFlow()
+            .map { transform(it) }
             .scan(Pair(initial, null), { last: Pair<R, DiffUtil.DiffResult?>, next: R ->
                 calculateDiff(last, next)
             })
             .drop(1)
-            .flowOn(Executors.newSingleThreadExecutor().asCoroutineDispatcher())
-            .onEach {
-                withContext(Dispatchers.Main) {
-                    applyDiff(it)
-                }
-            }
-            .launchIn(scope)
+            .flowOn(Dispatchers.Default)
+            .onEach { applyDiff(it) }
+            .launchIn(CoroutineScope(Dispatchers.Main + Job()))
         return initial
     }
 
diff --git a/app/src/main/java/org/tasks/tasklist/DragAndDropRecyclerAdapter.kt b/app/src/main/java/org/tasks/tasklist/DragAndDropRecyclerAdapter.kt
index ad08c6d9c..4bfaf3537 100644
--- a/app/src/main/java/org/tasks/tasklist/DragAndDropRecyclerAdapter.kt
+++ b/app/src/main/java/org/tasks/tasklist/DragAndDropRecyclerAdapter.kt
@@ -13,7 +13,7 @@ import com.todoroo.astrid.utility.Flags
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.asCoroutineDispatcher
-import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.runBlocking
 import org.tasks.activities.DragAndDropDiffer
 import org.tasks.data.TaskContainer
@@ -39,7 +39,7 @@ class DragAndDropRecyclerAdapter(
     private val itemTouchHelper = ItemTouchHelper(ItemTouchHelperCallback()).apply {
         attachToRecyclerView(recyclerView)
     }
-    override val flow = MutableSharedFlow<SectionedDataSource>()
+    override val channel = Channel<List<TaskContainer>>(Channel.UNLIMITED)
     override val updates: Queue<Pair<SectionedDataSource, DiffUtil.DiffResult?>> = LinkedList()
     override var dragging = false
     override val scope: CoroutineScope =