Migrate CacheCleaner to Coroutine

ultrasonic/src/main/kotlin/org/moire/ultrasonic/util/CacheCleaner.kt

@@ -1,10 +1,13 @@
 package org.moire.ultrasonic.util
 
-import android.os.AsyncTask
 import android.os.StatFs
 import java.io.File
 import java.util.ArrayList
 import java.util.HashSet
+import kotlinx.coroutines.CoroutineExceptionHandler
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 import org.koin.java.KoinJavaComponent.inject
 import org.moire.ultrasonic.data.ActiveServerProvider
 import org.moire.ultrasonic.domain.Playlist
@@ -22,42 +25,34 @@ import timber.log.Timber
 /**
  * Responsible for cleaning up files from the offline download cache on the filesystem.
  */
-class CacheCleaner {
+class CacheCleaner : CoroutineScope by CoroutineScope(Dispatchers.IO) {
+
+    private fun exceptionHandler(tag: String): CoroutineExceptionHandler {
+        return CoroutineExceptionHandler { _, exception ->
+            Timber.w(exception, "Exception in CacheCleaner.$tag")
+        }
+    }
+
     fun clean() {
-        try {
+        launch(exceptionHandler("clean")) {
-            BackgroundCleanup().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR)
+            backgroundCleanup()
-        } catch (all: Exception) {
-            // If an exception is thrown, assume we execute correctly the next time
-            Timber.w(all, "Exception in CacheCleaner.clean")
         }
     }
 
     fun cleanSpace() {
-        try {
+        launch(exceptionHandler("cleanSpace")) {
-            BackgroundSpaceCleanup().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR)
+            backgroundSpaceCleanup()
-        } catch (all: Exception) {
-            // If an exception is thrown, assume we execute correctly the next time
-            Timber.w(all, "Exception in CacheCleaner.cleanSpace")
         }
     }
 
     fun cleanPlaylists(playlists: List<Playlist>) {
-        try {
+        launch(exceptionHandler("cleanPlaylists")) {
-            BackgroundPlaylistsCleanup().executeOnExecutor(
+            backgroundPlaylistsCleanup(playlists)
-                AsyncTask.THREAD_POOL_EXECUTOR,
-                playlists
-            )
-        } catch (all: Exception) {
-            // If an exception is thrown, assume we execute correctly the next time
-            Timber.w(all, "Exception in CacheCleaner.cleanPlaylists")
         }
     }
 
-    private class BackgroundCleanup : AsyncTask<Void?, Void?, Void?>() {
+    private fun backgroundCleanup() {
-        override fun doInBackground(vararg params: Void?): Void? {
         try {
-                Thread.currentThread().name = "BackgroundCleanup"
-
             val files: MutableList<File> = ArrayList()
             val dirs: MutableList<File> = ArrayList()
 
@@ -70,42 +65,32 @@ class CacheCleaner {
         } catch (all: RuntimeException) {
             Timber.e(all, "Error in cache cleaning.")
         }
-            return null
-        }
     }
 
-    private class BackgroundSpaceCleanup : AsyncTask<Void?, Void?, Void?>() {
+    private fun backgroundSpaceCleanup() {
-        override fun doInBackground(vararg params: Void?): Void? {
         try {
-                Thread.currentThread().name = "BackgroundSpaceCleanup"
-
             val files: MutableList<File> = ArrayList()
             val dirs: MutableList<File> = ArrayList()
 
             findCandidatesForDeletion(musicDirectory, files, dirs)
 
             val bytesToDelete = getMinimumDelete(files)
-                if (bytesToDelete <= 0L) return null
+            if (bytesToDelete > 0L) {
-
                 sortByAscendingModificationTime(files)
                 val filesToNotDelete = findFilesToNotDelete()
                 deleteFiles(files, filesToNotDelete, bytesToDelete, false)
+            }
         } catch (all: RuntimeException) {
             Timber.e(all, "Error in cache cleaning.")
         }
-            return null
-        }
     }
 
-    private class BackgroundPlaylistsCleanup : AsyncTask<List<Playlist>, Void?, Void?>() {
+    private fun backgroundPlaylistsCleanup(vararg params: List<Playlist>) {
-        override fun doInBackground(vararg params: List<Playlist>): Void? {
         try {
             val activeServerProvider = inject<ActiveServerProvider>(
                 ActiveServerProvider::class.java
             )
 
-                Thread.currentThread().name = "BackgroundPlaylistsCleanup"
-
             val server = activeServerProvider.value.getActiveServer().name
             val playlistFiles = listFiles(getPlaylistDirectory(server))
             val playlists = params[0]
@@ -120,8 +105,6 @@ class CacheCleaner {
         } catch (all: RuntimeException) {
             Timber.e(all, "Error in playlist cache cleaning.")
         }
-            return null
-        }
     }
 
     companion object {