Improve FileNotFoundException handling (#1332)

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

@@ -28,9 +28,9 @@ fun File.subdir(name: String) = File(this, name).also {
 	if (!it.exists()) it.mkdirs()
 }
 
-fun File.takeIfReadable() = takeIf { it.exists() && it.canRead() }
+fun File.takeIfReadable() = takeIf { it.isReadable() }
 
-fun File.takeIfWriteable() = takeIf { it.exists() && it.canWrite() }
+fun File.takeIfWriteable() = takeIf { it.isWriteable() }
 
 fun File.isNotEmpty() = length() != 0L
 
@@ -110,3 +110,11 @@ fun File.walkCompat(includeDirectories: Boolean): Sequence<File> = if (Build.VER
 
 val File.normalizedExtension: String?
 	get() = MimeTypes.getNormalizedExtension(name)
+
+fun File.isReadable() = runCatching {
+	canRead()
+}.getOrDefault(false)
+
+fun File.isWriteable() = runCatching {
+	canWrite()
+}.getOrDefault(false)

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

@@ -41,6 +41,7 @@ import org.koitharu.kotatsu.parsers.exception.ParseException
 import org.koitharu.kotatsu.parsers.exception.TooManyRequestExceptions
 import org.koitharu.kotatsu.parsers.util.ifNullOrEmpty
 import org.koitharu.kotatsu.scrobbling.common.domain.ScrobblerAuthRequiredException
+import java.io.File
 import java.net.ConnectException
 import java.net.NoRouteToHostException
 import java.net.SocketException
@@ -52,6 +53,8 @@ private const val MSG_NO_SPACE_LEFT = "No space left on device"
 private const val MSG_CONNECTION_RESET = "Connection reset"
 private const val IMAGE_FORMAT_NOT_SUPPORTED = "Image format not supported"
 
+private val FNFE_MESSAGE_REGEX = Regex("^(/[^\\s:]+)?.+?\\s([A-Z]{2,6})?\\s.+$")
+
 fun Throwable.getDisplayMessage(resources: Resources): String = getDisplayMessageOrNull(resources)
 	?: resources.getString(R.string.error_occurred)
 
@@ -86,7 +89,7 @@ private fun Throwable.getDisplayMessageOrNull(resources: Resources): String? = w
 
 	is UnsupportedFileException -> resources.getString(R.string.text_file_not_supported)
 	is BadBackupFormatException -> resources.getString(R.string.unsupported_backup_message)
-	is FileNotFoundException -> resources.getString(R.string.file_not_found)
+	is FileNotFoundException -> parseMessage(resources) ?: message
 	is AccessDeniedException -> resources.getString(R.string.no_access_to_file)
 	is EmptyHistoryException -> resources.getString(R.string.history_is_empty)
 	is ProxyConfigException -> resources.getString(R.string.invalid_proxy_configuration)
@@ -225,3 +228,35 @@ fun Throwable.isWebViewUnavailable(): Boolean {
 
 @Suppress("FunctionName")
 fun NoSpaceLeftException() = IOException(MSG_NO_SPACE_LEFT)
+
+fun FileNotFoundException.getFile(): File? {
+	val groups = FNFE_MESSAGE_REGEX.matchEntire(message ?: return null)?.groupValues ?: return null
+	return groups.getOrNull(1)?.let { File(it) }
+}
+
+fun FileNotFoundException.parseMessage(resources: Resources): String? {
+	/*
+	Examples:
+	/storage/0000-0000/Android/media/d1f08350-0c25-460b-8f50-008e49de3873.jpg.tmp: open failed: EROFS (Read-only file system)
+	 /storage/emulated/0/Android/data/org.koitharu.kotatsu/cache/pages/fe06e192fa371e55918980f7a24c91ea.jpg: open failed: ENOENT (No such file or directory)
+	 /storage/0000-0000/Android/data/org.koitharu.kotatsu/files/manga/e57d3af4-216e-48b2-8432-1541d58eea1e.tmp (I/O error)
+	 */
+	val groups = FNFE_MESSAGE_REGEX.matchEntire(message ?: return null)?.groupValues ?: return null
+	val path = groups.getOrNull(1)
+	val error = groups.getOrNull(2)
+	val baseMessageIs = when (error) {
+		"EROFS" -> R.string.no_write_permission_to_file
+		"ENOENT" -> R.string.file_not_found
+		else -> return null
+	}
+	return if (path.isNullOrEmpty()) {
+		resources.getString(baseMessageIs)
+	} else {
+		resources.getString(
+			R.string.inline_preference_pattern,
+			resources.getString(baseMessageIs),
+			path,
+		)
+	}
+}
+

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

@@ -17,7 +17,9 @@ import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.util.AlphanumComparator
 import org.koitharu.kotatsu.core.util.ext.deleteAwait
+import org.koitharu.kotatsu.core.util.ext.isWriteable
 import org.koitharu.kotatsu.core.util.ext.printStackTraceDebug
+import org.koitharu.kotatsu.core.util.ext.takeIfWriteable
 import org.koitharu.kotatsu.core.util.ext.withChildren
 import org.koitharu.kotatsu.local.data.index.LocalMangaIndex
 import org.koitharu.kotatsu.local.data.input.LocalMangaParser
@@ -203,7 +205,7 @@ class LocalMangaRepository @Inject constructor(
 	override suspend fun getRelated(seed: Manga): List<Manga> = emptyList()
 
 	suspend fun getOutputDir(manga: Manga, fallback: File?): File? {
-		val defaultDir = fallback ?: storageManager.getDefaultWriteableDir()
+		val defaultDir = fallback?.takeIfWriteable() ?: storageManager.getDefaultWriteableDir()
 		if (defaultDir != null && LocalMangaOutput.get(defaultDir, manga) != null) {
 			return defaultDir
 		}

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

@@ -22,7 +22,10 @@ import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.util.ext.computeSize
 import org.koitharu.kotatsu.core.util.ext.getStorageName
 import org.koitharu.kotatsu.core.util.ext.isFileUri
+import org.koitharu.kotatsu.core.util.ext.isReadable
+import org.koitharu.kotatsu.core.util.ext.isWriteable
 import org.koitharu.kotatsu.core.util.ext.resolveFile
+import org.koitharu.kotatsu.core.util.ext.takeIfWriteable
 import org.koitharu.kotatsu.parsers.util.mapToSet
 import java.io.File
 import javax.inject.Inject
@@ -81,8 +84,8 @@ class LocalStorageManager @Inject constructor(
 	}
 
 	suspend fun getDefaultWriteableDir(): File? = runInterruptible(Dispatchers.IO) {
-		val preferredDir = settings.mangaStorageDir?.takeIf { it.isWriteable() }
+		val preferredDir = settings.mangaStorageDir?.takeIfWriteable()
-		preferredDir ?: getFallbackStorageDir()?.takeIf { it.isWriteable() }
+		preferredDir ?: getFallbackStorageDir()?.takeIfWriteable()
 	}
 
 	suspend fun getApplicationStorageDirs(): Set<File> = runInterruptible(Dispatchers.IO) {
@@ -184,12 +187,4 @@ class LocalStorageManager @Inject constructor(
 			CACHE_SIZE_MIN
 		}
 	}
-
-	private fun File.isReadable() = runCatching {
-		canRead()
-	}.getOrDefault(false)
-
-	private fun File.isWriteable() = runCatching {
-		canWrite()
-	}.getOrDefault(false)
 }

app/src/main/kotlin/org/koitharu/kotatsu/settings/storage/MangaDirectorySelectViewModel.kt

@@ -9,6 +9,7 @@ import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.ui.BaseViewModel
 import org.koitharu.kotatsu.core.util.ext.MutableEventFlow
 import org.koitharu.kotatsu.core.util.ext.call
+import org.koitharu.kotatsu.core.util.ext.isWriteable
 import org.koitharu.kotatsu.local.data.LocalStorageManager
 import javax.inject.Inject
 
@@ -41,7 +42,7 @@ class MangaDirectorySelectViewModel @Inject constructor(
 			val dir = requireNotNull(storageManager.resolveUri(uri)) {
 				"Cannot resolve file name of \"$uri\""
 			}
-			if (!dir.canWrite()) {
+			if (!dir.isWriteable()) {
 				throw AccessDeniedException(dir)
 			}
 			if (dir !in storageManager.getApplicationStorageDirs()) {

app/src/main/kotlin/org/koitharu/kotatsu/settings/storage/directories/MangaDirectoriesViewModel.kt

@@ -8,6 +8,8 @@ import kotlinx.coroutines.cancelAndJoin
 import kotlinx.coroutines.flow.MutableStateFlow
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.ui.BaseViewModel
+import org.koitharu.kotatsu.core.util.ext.isReadable
+import org.koitharu.kotatsu.core.util.ext.isWriteable
 import org.koitharu.kotatsu.local.data.LocalStorageManager
 import org.koitharu.kotatsu.settings.storage.DirectoryModel
 import java.io.File
@@ -69,7 +71,7 @@ class MangaDirectoriesViewModel @Inject constructor(
 						titleRes = 0,
 						file = dir,
 						isChecked = dir == downloadDir,
-						isAvailable = dir.canRead() && dir.canWrite(),
+						isAvailable = dir.isReadable() && dir.isWriteable(),
 						isRemovable = false,
 					)
 				}
@@ -79,7 +81,7 @@ class MangaDirectoriesViewModel @Inject constructor(
 						titleRes = 0,
 						file = dir,
 						isChecked = dir == downloadDir,
-						isAvailable = dir.canRead() && dir.canWrite(),
+						isAvailable = dir.isReadable() && dir.isWriteable(),
 						isRemovable = true,
 					)
 				}

app/src/main/res/values/strings.xml

@@ -818,4 +818,5 @@
 	<string name="link_to_manga_in_app">Link to manga in Kotatsu</string>
 	<string name="clear_browser_data">Clear browser data</string>
 	<string name="clear_browser_data_summary">Clear browser data such as cache and cookies. Warning: Authorization in manga sources may become invalid</string>
+	<string name="no_write_permission_to_file">Does not have permission to write a file</string>
 </resources>