Merge pull request #10 from xxDark/master

Add fallback path for locked-up environments

Author: Col-E

src/main/java/software/coley/llzip/util/BufferData.java

@@ -6,34 +6,39 @@
 import java.nio.ByteOrder;
 
 /**
- * Mapped file that is backed by byte buffer.
+ * File that is backed by a byte buffer.
  *
  * @author xDark
  */
 public final class BufferData implements ByteData {
 	private final ByteBuffer buffer;
+	private volatile boolean cleaned;
 
 	private BufferData(ByteBuffer buffer) {
 		this.buffer = buffer;
 	}
 
 	@Override
 	public int getInt(long position) {
+		ensureOpen();
 		return buffer.getInt(validate(position));
 	}
 
 	@Override
 	public short getShort(long position) {
+		ensureOpen();
 		return buffer.getShort(validate(position));
 	}
 
 	@Override
 	public byte get(long position) {
+		ensureOpen();
 		return buffer.get(validate(position));
 	}
 
 	@Override
 	public void get(long position, byte[] b, int off, int len) {
+		ensureOpen();
 		ByteBuffer buffer = this.buffer;
 		((ByteBuffer) buffer.slice()
 				.order(buffer.order())
@@ -43,6 +48,7 @@ public void get(long position, byte[] b, int off, int len) {
 
 	@Override
 	public void transferTo(OutputStream out, byte[] buf) throws IOException {
+		ensureOpen();
 		ByteBuffer buffer = this.buffer;
 		int remaining = buffer.remaining();
 		if (buffer.hasArray()) {
@@ -62,11 +68,13 @@ public void transferTo(OutputStream out, byte[] buf) throws IOException {
 
 	@Override
 	public ByteData slice(long startIndex, long endIndex) {
+		ensureOpen();
 		return new BufferData(ByteDataUtil.sliceExact(buffer, validate(startIndex), validate(endIndex)));
 	}
 
 	@Override
 	public long length() {
+		ensureOpen();
 		return ByteDataUtil.length(buffer);
 	}
 
@@ -83,6 +91,35 @@ public int hashCode() {
 		return buffer.hashCode();
 	}
 
+	@Override
+	public void close() {
+		if (!cleaned) {
+			synchronized (this) {
+				if (cleaned)
+					return;
+				cleaned = true;
+				ByteBuffer buffer = this.buffer;
+				if (buffer.isDirect()) {
+					CleanerUtil.invokeCleaner(buffer);
+				}
+			}
+		}
+	}
+
+	@Override
+	protected void finalize() throws Throwable {
+		try {
+			close();
+		} finally {
+			super.finalize();
+		}
+	}
+
+	private void ensureOpen() {
+		if (cleaned)
+			throw new IllegalStateException("Cannot access data after close");
+	}
+
 	private static int validate(long v) {
 		if (v < 0L || v > Integer.MAX_VALUE) {
 			throw new IllegalArgumentException(Long.toString(v));

src/main/java/software/coley/llzip/util/ByteData.java

@@ -1,5 +1,6 @@
 package software.coley.llzip.util;
 
+import java.io.Closeable;
 import java.io.IOException;
 import java.io.OutputStream;
 
@@ -8,7 +9,7 @@
  *
  * @author xDark
  */
-public interface ByteData {
+public interface ByteData extends Closeable {
 	/**
 	 * Gets int at specific position.
 	 *

src/main/java/software/coley/llzip/util/CleanerUtil.java

@@ -0,0 +1,91 @@
+package software.coley.llzip.util;
+
+import sun.misc.Unsafe;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.nio.ByteBuffer;
+
+/**
+ * Utility to invoke cleaners in a {@link ByteBuffer}.
+ *
+ * @author xDark
+ */
+public final class CleanerUtil {
+
+	private static final Method INVOKE_CLEANER;
+	private static final Method GET_CLEANER;
+	private static final boolean SUPPORTED;
+
+	private CleanerUtil() {
+	}
+
+	/**
+	 * Attempts to clean direct buffer.
+	 *
+	 * @param buffer
+	 * 		Buffer to clean.
+	 *
+	 * @throws IllegalStateException
+	 * 		If buffer is not direct, slice or duplicate, or
+	 * 		cleaner failed to invoke.
+	 */
+	public static void invokeCleaner(ByteBuffer buffer) {
+		if (!buffer.isDirect()) {
+			throw new IllegalStateException("buffer is not direct");
+		}
+		if (!SUPPORTED) {
+			return;
+		}
+		Method getCleaner = GET_CLEANER;
+		Method invokeCleaner = INVOKE_CLEANER;
+		try {
+			if (getCleaner != null) {
+				Object cleaner = getCleaner.invoke(buffer);
+				if (cleaner == null) {
+					throw new IllegalStateException("slice or duplicate");
+				}
+				invokeCleaner.invoke(cleaner);
+			} else {
+				invokeCleaner.invoke(UnsafeUtil.get(), buffer);
+			}
+		} catch(InvocationTargetException ex) {
+			throw new IllegalStateException("Failed to invoke clean method", ex.getTargetException());
+		} catch(IllegalAccessException ex) {
+			throw new IllegalStateException("cleaner became inaccessible", ex);
+		}
+	}
+
+	static {
+		boolean supported = false;
+		Method invokeCleaner;
+		Method getCleaner = null;
+		try {
+			invokeCleaner = Unsafe.class.getDeclaredMethod("invokeCleaner", ByteBuffer.class);
+			invokeCleaner.setAccessible(true);
+			ByteBuffer tmp = ByteBuffer.allocateDirect(1);
+			invokeCleaner.invoke(UnsafeUtil.get(), tmp);
+			supported = true;
+		} catch(NoSuchMethodException ignored) {
+			supported = true;
+			ByteBuffer tmp = ByteBuffer.allocateDirect(1);
+			try {
+				Class<?> directBuffer = Class.forName("sun.nio.ch.DirectBuffer");
+				getCleaner = directBuffer.getDeclaredMethod("cleaner");
+				invokeCleaner = getCleaner.getReturnType().getDeclaredMethod("clean");
+				invokeCleaner.setAccessible(true);
+				getCleaner.setAccessible(true);
+				invokeCleaner.invoke(getCleaner.invoke(tmp));
+			} catch(Exception ignored1) {
+				invokeCleaner = null;
+				getCleaner = null;
+				supported = false;
+			}
+		} catch(Exception ex) {
+			invokeCleaner = null;
+		}
+		INVOKE_CLEANER = invokeCleaner;
+		GET_CLEANER = getCleaner;
+		SUPPORTED = supported;
+	}
+}

src/main/java/software/coley/llzip/util/FileMapUtil.java

@@ -3,7 +3,10 @@
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.nio.ByteOrder;
+import java.nio.MappedByteBuffer;
 import java.nio.channels.FileChannel;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 
@@ -27,9 +30,24 @@ public class FileMapUtil {
 	 *
 	 * @throws IOException
 	 * 		If any I/O error occurs.
+	 * @throws IllegalStateException
+	 * 		If the environment is locked up and
+	 * 		file is larger than 2GB.
 	 */
 	public static ByteData map(Path path) throws IOException {
-		try (FileChannel fc = FileChannel.open(path, StandardOpenOption.READ)) {
+		if (MAP == null) {
+			long size = Files.size(path);
+			if (size <= Integer.MAX_VALUE) {
+				try(FileChannel fc = FileChannel.open(path, StandardOpenOption.READ)) {
+					long length = fc.size();
+					MappedByteBuffer buffer = fc.map(FileChannel.MapMode.READ_ONLY, 0L, length);
+					buffer.order(ByteOrder.LITTLE_ENDIAN);
+					return BufferData.wrap(buffer);
+				}
+			}
+			throw new IllegalStateException("Cannot map more than 2GB of data in locked up environment");
+		}
+		try(FileChannel fc = FileChannel.open(path, StandardOpenOption.READ)) {
 			long length = fc.size();
 			long address;
 			try {
@@ -38,13 +56,13 @@ public static ByteData map(Path path) throws IOException {
 				} else {
 					address = (long) MAP.invoke(fc, 0, 0L, length, false);
 				}
-			} catch (InvocationTargetException | IllegalAccessException ex) {
+			} catch(InvocationTargetException | IllegalAccessException ex) {
 				throw new IllegalStateException("Could not invoke map0", ex);
 			}
 			ByteData mappedFile = new UnsafeMappedFile(address, length, () -> {
 				try {
 					UNMAP.invoke(null, address, length);
-				} catch (IllegalAccessException | InvocationTargetException ex) {
+				} catch(IllegalAccessException | InvocationTargetException ex) {
 					throw new InternalError(ex);
 				}
 			});
@@ -54,23 +72,38 @@ public static ByteData map(Path path) throws IOException {
 
 	static {
 		boolean oldMap = false;
-		try {
-			Class<?> c = Class.forName("sun.nio.ch.FileChannelImpl");
-			Method map;
+		Method map = null;
+		Method unmap = null;
+		get:
+		{
+			Class<?> c;
+			try {
+				c = Class.forName("sun.nio.ch.FileChannelImpl");
+			} catch(ClassNotFoundException ignored) {
+				break get;
+			}
 			try {
 				map = c.getDeclaredMethod("map0", int.class, long.class, long.class, boolean.class);
-			} catch (NoSuchMethodException ex) {
-				map = c.getDeclaredMethod("map0", int.class, long.class, long.class);
-				oldMap = true;
+			} catch(NoSuchMethodException ex) {
+				try {
+					map = c.getDeclaredMethod("map0", int.class, long.class, long.class);
+					oldMap = true;
+				} catch(NoSuchMethodException ignored) {
+					break get;
+				}
+			}
+			try {
+				map.setAccessible(true);
+				unmap = c.getDeclaredMethod("unmap0", long.class, long.class);
+				unmap.setAccessible(true);
+			} catch(Exception ex) {
+				// Locked up environment, probably threw InaccessibleObjectException
+				map = null;
+				unmap = null;
 			}
-			map.setAccessible(true);
-			Method unmap = c.getDeclaredMethod("unmap0", long.class, long.class);
-			unmap.setAccessible(true);
-			MAP = map;
-			UNMAP = unmap;
-			OLD_MAP = oldMap;
-		} catch (ClassNotFoundException | NoSuchMethodException ex) {
-			throw new ExceptionInInitializerError(ex);
 		}
+		MAP = map;
+		UNMAP = unmap;
+		OLD_MAP = oldMap;
 	}
 }