Use nio for File.listFiles() #449

app/src/main/kotlin/org/koitharu/kotatsu/core/fs/FileSequence.kt

@@ -0,0 +1,20 @@
+package org.koitharu.kotatsu.core.fs
+
+import android.os.Build
+import org.koitharu.kotatsu.core.util.iterator.CloseableIterator
+import org.koitharu.kotatsu.core.util.iterator.MappingIterator
+import java.io.File
+import java.nio.file.Files
+import java.nio.file.Path
+
+class FileSequence(private val dir: File) : Sequence<File> {
+
+	override fun iterator(): Iterator<File> {
+		return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+			val stream = Files.newDirectoryStream(dir.toPath())
+			CloseableIterator(MappingIterator(stream.iterator(), Path::toFile), stream)
+		} else {
+			dir.listFiles().orEmpty().iterator()
+		}
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ext/File.kt

@@ -13,6 +13,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.runInterruptible
 import kotlinx.coroutines.withContext
 import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.fs.FileSequence
 import java.io.File
 import java.io.FileFilter
 import java.util.zip.ZipEntry
@@ -73,11 +74,10 @@ suspend fun File.computeSize(): Long = runInterruptible(Dispatchers.IO) {
 
 @WorkerThread
 private fun computeSizeInternal(file: File): Long {
-	if (file.isDirectory) {
-		val files = file.listFiles() ?: return 0L
-		return files.sumOf { computeSizeInternal(it) }
+	return if (file.isDirectory) {
+		file.children().sumOf { computeSizeInternal(it) }
 	} else {
-		return file.length()
+		file.length()
 	}
 }
 
@@ -86,9 +86,8 @@ fun File.listFilesRecursive(filter: FileFilter? = null): Sequence<File> = sequen
 }
 
 private suspend fun SequenceScope<File>.listFilesRecursiveImpl(root: File, filter: FileFilter?) {
-	val ss = root.list() ?: return
-	for (s in ss) {
-		val f = File(root, s)
+	val ss = root.children()
+	for (f in ss) {
 		if (f.isDirectory) {
 			listFilesRecursiveImpl(f, filter)
 		} else if (filter == null || filter.accept(f)) {
@@ -96,3 +95,7 @@ private suspend fun SequenceScope<File>.listFilesRecursiveImpl(root: File, filte
 		}
 	}
 }
+
+fun File.children() = FileSequence(this)
+
+fun Sequence<File>.filterWith(filter: FileFilter): Sequence<File> = filter { f -> filter.accept(f) }

app/src/main/kotlin/org/koitharu/kotatsu/core/util/iterator/CloseableIterator.kt

@@ -0,0 +1,36 @@
+package org.koitharu.kotatsu.core.util.iterator
+
+import okhttp3.internal.closeQuietly
+import okio.Closeable
+
+class CloseableIterator<T>(
+	private val upstream: Iterator<T>,
+	private val closeable: Closeable,
+) : Iterator<T>, Closeable {
+
+	private var isClosed = false
+
+	override fun hasNext(): Boolean {
+		val result = upstream.hasNext()
+		if (!result) {
+			close()
+		}
+		return result
+	}
+
+	override fun next(): T {
+		try {
+			return upstream.next()
+		} catch (e: NoSuchElementException) {
+			close()
+			throw e
+		}
+	}
+
+	override fun close() {
+		if (!isClosed) {
+			closeable.closeQuietly()
+			isClosed = true
+		}
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/core/util/iterator/MappingIterator.kt

@@ -0,0 +1,13 @@
+package org.koitharu.kotatsu.core.util.iterator
+
+import org.koitharu.kotatsu.R
+
+class MappingIterator<T, R>(
+	private val upstream: Iterator<T>,
+	private val mapper: (T) -> R,
+) : Iterator<R> {
+
+	override fun hasNext(): Boolean = upstream.hasNext()
+
+	override fun next(): R = mapper(upstream.next())
+}

app/src/main/kotlin/org/koitharu/kotatsu/core/zip/ZipOutput.kt

@@ -3,6 +3,7 @@ package org.koitharu.kotatsu.core.zip
 import androidx.annotation.WorkerThread
 import androidx.collection.ArraySet
 import okio.Closeable
+import org.koitharu.kotatsu.core.util.ext.children
 import java.io.File
 import java.io.FileInputStream
 import java.util.zip.Deflater
@@ -90,7 +91,7 @@ class ZipOutput(
 			}
 			putNextEntry(entry)
 			closeEntry()
-			fileToZip.listFiles()?.forEach { childFile ->
+			fileToZip.children().forEach { childFile ->
 				appendFile(childFile, "$name/${childFile.name}")
 			}
 		} else {

app/src/main/kotlin/org/koitharu/kotatsu/local/data/LocalMangaRepository.kt

@@ -15,7 +15,9 @@ import org.koitharu.kotatsu.core.model.isLocal
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.util.CompositeMutex
+import org.koitharu.kotatsu.core.util.ext.children
 import org.koitharu.kotatsu.core.util.ext.deleteAwait
+import org.koitharu.kotatsu.core.util.ext.filterWith
 import org.koitharu.kotatsu.core.util.ext.printStackTraceDebug
 import org.koitharu.kotatsu.local.data.input.LocalMangaInput
 import org.koitharu.kotatsu.local.data.output.LocalMangaOutput
@@ -128,9 +130,6 @@ class LocalMangaRepository @Inject constructor(
 
 	suspend fun findSavedManga(remoteManga: Manga): LocalManga? {
 		val files = getAllFiles()
-		if (files.isEmpty()) {
-			return null
-		}
 		return channelFlow {
 			for (file in files) {
 				launch {
@@ -172,7 +171,7 @@ class LocalMangaRepository @Inject constructor(
 		val dirs = storageManager.getWriteableDirs()
 		runInterruptible(Dispatchers.IO) {
 			dirs.flatMap { dir ->
-				dir.listFiles(TempFileFilter())?.toList().orEmpty()
+				dir.children().filterWith(TempFileFilter())
 			}.forEach { file ->
 				file.deleteRecursively()
 			}
@@ -189,7 +188,7 @@ class LocalMangaRepository @Inject constructor(
 	}
 
 	private suspend fun getRawList(): ArrayList<LocalManga> {
-		val files = getAllFiles()
+		val files = getAllFiles().toList() // TODO remove toList()
 		return coroutineScope {
 			val dispatcher = Dispatchers.IO.limitedParallelism(MAX_PARALLELISM)
 			files.map { file ->
@@ -200,8 +199,8 @@ class LocalMangaRepository @Inject constructor(
 		}.filterNotNullTo(ArrayList(files.size))
 	}
 
-	private suspend fun getAllFiles() = storageManager.getReadableDirs().flatMap { dir ->
-		dir.listFiles()?.toList().orEmpty()
+	private suspend fun getAllFiles() = storageManager.getReadableDirs().asSequence().flatMap { dir ->
+		dir.children()
 	}
 
 	private fun Collection<LocalManga>.unwrap(): List<Manga> = map { it.manga }

app/src/main/kotlin/org/koitharu/kotatsu/local/data/TempFileFilter.kt

@@ -1,11 +1,16 @@
 package org.koitharu.kotatsu.local.data
 
 import java.io.File
+import java.io.FileFilter
 import java.io.FilenameFilter
 
-class TempFileFilter : FilenameFilter {
+class TempFileFilter : FilenameFilter, FileFilter {
 
 	override fun accept(dir: File, name: String): Boolean {
 		return name.endsWith(".tmp", ignoreCase = true)
 	}
+
+	override fun accept(file: File): Boolean {
+		return file.name.endsWith(".tmp", ignoreCase = true)
+	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/local/data/input/LocalMangaDirInput.kt

@@ -4,6 +4,7 @@ import androidx.core.net.toFile
 import androidx.core.net.toUri
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.runInterruptible
+import org.koitharu.kotatsu.core.util.AlphanumComparator
 import org.koitharu.kotatsu.core.util.ext.listFilesRecursive
 import org.koitharu.kotatsu.core.util.ext.longHashCode
 import org.koitharu.kotatsu.core.util.ext.toListSorted
@@ -88,7 +89,7 @@ class LocalMangaDirInput(root: File) : LocalMangaInput(root) {
 		val file = chapter.url.toUri().toFile()
 		if (file.isDirectory) {
 			file.listFilesRecursive(ImageFileFilter())
-				.toListSorted(compareBy(org.koitharu.kotatsu.core.util.AlphanumComparator()) { x -> x.name })
+				.toListSorted(compareBy(AlphanumComparator()) { x -> x.name })
 				.map {
 					val pageUri = it.toUri().toString()
 					MangaPage(
@@ -104,7 +105,7 @@ class LocalMangaDirInput(root: File) : LocalMangaInput(root) {
 					.asSequence()
 					.filter { x -> !x.isDirectory }
 					.map { it.name }
-					.toListSorted(org.koitharu.kotatsu.core.util.AlphanumComparator())
+					.toListSorted(AlphanumComparator())
 					.map {
 						val pageUri = zipUri(file, it)
 						MangaPage(
@@ -121,7 +122,7 @@ class LocalMangaDirInput(root: File) : LocalMangaInput(root) {
 	private fun String.toHumanReadable() = replace("_", " ").toCamelCase()
 
 	private fun getChaptersFiles(): List<File> = root.listFilesRecursive(CbzFilter())
-		.toListSorted(compareBy(org.koitharu.kotatsu.core.util.AlphanumComparator()) { x -> x.name })
+		.toListSorted(compareBy(AlphanumComparator()) { x -> x.name })
 
 	private fun findFirstImageEntry(): String? {
 		val filter = ImageFileFilter()