more fault-tolerant behaviour when mapping of long filenames couldn't be found.

main/filesystem-nameshortening/src/main/java/org/cryptomator/filesystem/shortening/FilenameShortener.java

@@ -8,8 +8,6 @@
  *******************************************************************************/
 package org.cryptomator.filesystem.shortening;
 
-import java.io.FileNotFoundException;
-import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -19,9 +17,12 @@ import org.apache.commons.codec.binary.BaseNCodec;
 import org.cryptomator.filesystem.File;
 import org.cryptomator.filesystem.Folder;
 import org.cryptomator.io.FileContents;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 class FilenameShortener {
 
+	private static final Logger LOG = LoggerFactory.getLogger(FilenameShortener.class);
 	private static final String LONG_NAME_FILE_EXT = ".lng";
 	private static final ThreadLocal<MessageDigest> SHA1 = new ThreadLocalSha1();
 	private static final BaseNCodec BASE32 = new Base32();
@@ -71,7 +72,8 @@ class FilenameShortener {
 	private String loadMapping(String shortName) {
 		final File mappingFile = mappingFile(shortName);
 		if (!mappingFile.exists()) {
-			throw new UncheckedIOException(new FileNotFoundException("Mapping file not found " + mappingFile));
+			LOG.warn("Mapping file not found: " + mappingFile);
+			return shortName;
 		} else {
 			return FileContents.UTF_8.readContents(mappingFile);
 		}

main/filesystem-nameshortening/src/test/java/org/cryptomator/filesystem/shortening/FilenameShortenerTest.java

@@ -8,8 +8,6 @@
  *******************************************************************************/
 package org.cryptomator.filesystem.shortening;
 
-import java.io.UncheckedIOException;
-
 import org.cryptomator.filesystem.FileSystem;
 import org.cryptomator.filesystem.inmem.InMemoryFileSystem;
 import org.junit.Assert;
@@ -45,12 +43,12 @@ public class FilenameShortenerTest {
 		Assert.assertEquals("short", shortener.inflate("short"));
 	}
 
-	@Test(expected = UncheckedIOException.class)
+	@Test
 	public void testInflateWithoutMappingFile() {
 		FileSystem fs = new InMemoryFileSystem();
 		FilenameShortener shortener = new FilenameShortener(fs, 10);
 
-		shortener.inflate("iJustMadeThisNameUp.lng");
+		Assert.assertEquals("iJustMadeThisNameUp.lng", shortener.inflate("iJustMadeThisNameUp.lng"));
 	}
 
 }

main/filesystem-nameshortening/src/test/java/org/cryptomator/filesystem/shortening/ShorteningFileSystemTest.java

@@ -16,6 +16,7 @@ import static org.junit.Assert.assertThat;
 
 import java.io.UncheckedIOException;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.time.Instant;
 import java.util.concurrent.TimeoutException;
 
@@ -102,6 +103,31 @@ public class ShorteningFileSystemTest {
 		Assert.assertTrue(correspondingMetadataFile.exists());
 	}
 
+	@Test
+	public void testInflate() {
+		final FileSystem underlyingFs = new InMemoryFileSystem();
+		final Folder metadataRoot = underlyingFs.folder(METADATA_DIR_NAME);
+		final FileSystem fs = new ShorteningFileSystem(underlyingFs, METADATA_DIR_NAME, 10);
+		final File correspondingMetadataFile = metadataRoot.folder("QM").folder("JL").file("QMJL5GQUETRX2YRV6XDTJQ6NNM7IEUHP.lng");
+		final Folder shortenedFolder = underlyingFs.folder("QMJL5GQUETRX2YRV6XDTJQ6NNM7IEUHP.lng");
+		shortenedFolder.create();
+		correspondingMetadataFile.parent().get().create();
+		try (WritableFile w = correspondingMetadataFile.openWritable()) {
+			w.write(ByteBuffer.wrap("morethantenchars".getBytes(StandardCharsets.UTF_8)));
+		}
+		Assert.assertTrue(correspondingMetadataFile.exists());
+		Assert.assertTrue(fs.folders().map(Folder::name).anyMatch(n -> n.equals("morethantenchars")));
+	}
+
+	@Test
+	public void testInflateFailedDueToMissingMapping() {
+		final FileSystem underlyingFs = new InMemoryFileSystem();
+		final FileSystem fs = new ShorteningFileSystem(underlyingFs, METADATA_DIR_NAME, 10);
+		final Folder shortenedFolder = underlyingFs.folder("QMJL5GQUETRX2YRV6XDTJQ6NNM7IEUHP.lng");
+		shortenedFolder.create();
+		Assert.assertTrue(fs.folders().map(Folder::name).anyMatch(n -> n.equals("QMJL5GQUETRX2YRV6XDTJQ6NNM7IEUHP.lng")));
+	}
+
 	@Test
 	public void testMoveLongFolders() {
 		final FileSystem underlyingFs = new InMemoryFileSystem();

main/filesystem-nameshortening/src/test/resources/log4j2.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<Configuration status="WARN">
+
+	<Appenders>
+		<Console name="Console" target="SYSTEM_OUT">
+			<PatternLayout pattern="%16d %-5p [%c{1}:%L] %m%n" />
+			<ThresholdFilter level="WARN" onMatch="DENY" onMismatch="ACCEPT" />
+		</Console>
+		<Console name="StdErr" target="SYSTEM_ERR">
+			<PatternLayout pattern="%16d %-5p [%c{1}:%L] %m%n" />
+			<ThresholdFilter level="WARN" onMatch="ACCEPT" onMismatch="DENY" />
+		</Console>
+	</Appenders>
+
+	<Loggers>
+		<Root level="DEBUG">
+			<AppenderRef ref="Console" />
+			<AppenderRef ref="StdErr" />
+		</Root>
+	</Loggers>
+
+</Configuration>