8196535: Remove support for pre-Java 6 non-JVM-wide file locking
Reviewed-by: alanb, rriggs
--- a/src/java.base/share/classes/sun/nio/ch/AsynchronousFileChannelImpl.java Mon Feb 05 11:35:56 2018 -0800
+++ b/src/java.base/share/classes/sun/nio/ch/AsynchronousFileChannelImpl.java Mon Feb 05 15:08:46 2018 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -136,7 +136,7 @@
if (fileLockTable == null) {
synchronized (this) {
if (fileLockTable == null) {
- fileLockTable = FileLockTable.newSharedFileLockTable(this, fdObj);
+ fileLockTable = new FileLockTable(this, fdObj);
}
}
}
--- a/src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java Mon Feb 05 11:35:56 2018 -0800
+++ b/src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java Mon Feb 05 15:08:46 2018 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -1083,49 +1083,19 @@
// -- Locks --
-
-
// keeps track of locks on this file
private volatile FileLockTable fileLockTable;
- // indicates if file locks are maintained system-wide (as per spec)
- private static boolean isSharedFileLockTable;
-
- // indicates if the disableSystemWideOverlappingFileLockCheck property
- // has been checked
- private static volatile boolean propertyChecked;
-
- // The lock list in J2SE 1.4/5.0 was local to each FileChannel instance so
- // the overlap check wasn't system wide when there were multiple channels to
- // the same file. This property is used to get 1.4/5.0 behavior if desired.
- private static boolean isSharedFileLockTable() {
- if (!propertyChecked) {
- synchronized (FileChannelImpl.class) {
- if (!propertyChecked) {
- String value = GetPropertyAction.privilegedGetProperty(
- "sun.nio.ch.disableSystemWideOverlappingFileLockCheck");
- isSharedFileLockTable = ((value == null) || value.equals("false"));
- propertyChecked = true;
- }
- }
- }
- return isSharedFileLockTable;
- }
-
private FileLockTable fileLockTable() throws IOException {
if (fileLockTable == null) {
synchronized (this) {
if (fileLockTable == null) {
- if (isSharedFileLockTable()) {
- int ti = threads.add();
- try {
- ensureOpen();
- fileLockTable = FileLockTable.newSharedFileLockTable(this, fd);
- } finally {
- threads.remove(ti);
- }
- } else {
- fileLockTable = new SimpleFileLockTable();
+ int ti = threads.add();
+ try {
+ ensureOpen();
+ fileLockTable = new FileLockTable(this, fd);
+ } finally {
+ threads.remove(ti);
}
}
}
@@ -1229,59 +1199,6 @@
fileLockTable.remove(fli);
}
- // -- File lock support --
-
- /**
- * A simple file lock table that maintains a list of FileLocks obtained by a
- * FileChannel. Use to get 1.4/5.0 behaviour.
- */
- private static class SimpleFileLockTable extends FileLockTable {
- // synchronize on list for access
- private final List<FileLock> lockList = new ArrayList<FileLock>(2);
-
- public SimpleFileLockTable() {
- }
-
- private void checkList(long position, long size)
- throws OverlappingFileLockException
- {
- assert Thread.holdsLock(lockList);
- for (FileLock fl: lockList) {
- if (fl.overlaps(position, size)) {
- throw new OverlappingFileLockException();
- }
- }
- }
-
- public void add(FileLock fl) throws OverlappingFileLockException {
- synchronized (lockList) {
- checkList(fl.position(), fl.size());
- lockList.add(fl);
- }
- }
-
- public void remove(FileLock fl) {
- synchronized (lockList) {
- lockList.remove(fl);
- }
- }
-
- public List<FileLock> removeAll() {
- synchronized(lockList) {
- List<FileLock> result = new ArrayList<FileLock>(lockList);
- lockList.clear();
- return result;
- }
- }
-
- public void replace(FileLock fl1, FileLock fl2) {
- synchronized (lockList) {
- lockList.remove(fl1);
- lockList.add(fl2);
- }
- }
- }
-
// -- Native methods --
// Creates a new mapping
--- a/src/java.base/share/classes/sun/nio/ch/FileLockTable.java Mon Feb 05 11:35:56 2018 -0800
+++ b/src/java.base/share/classes/sun/nio/ch/FileLockTable.java Mon Feb 05 15:08:46 2018 -0800
@@ -25,64 +25,27 @@
package sun.nio.ch;
-import java.nio.channels.*;
-import java.util.*;
-import java.util.concurrent.ConcurrentHashMap;
-import java.lang.ref.*;
import java.io.FileDescriptor;
import java.io.IOException;
-
-abstract class FileLockTable {
- protected FileLockTable() {
- }
-
- /**
- * Creates and returns a file lock table for a channel that is connected to
- * the a system-wide map of all file locks for the Java virtual machine.
- */
- public static FileLockTable newSharedFileLockTable(Channel channel,
- FileDescriptor fd)
- throws IOException
- {
- return new SharedFileLockTable(channel, fd);
- }
-
- /**
- * Adds a file lock to the table.
- *
- * @throws OverlappingFileLockException if the file lock overlaps
- * with an existing file lock in the table
- */
- public abstract void add(FileLock fl) throws OverlappingFileLockException;
-
- /**
- * Remove an existing file lock from the table.
- */
- public abstract void remove(FileLock fl);
-
- /**
- * Removes all file locks from the table.
- *
- * @return The list of file locks removed
- */
- public abstract List<FileLock> removeAll();
-
- /**
- * Replaces an existing file lock in the table.
- */
- public abstract void replace(FileLock fl1, FileLock fl2);
-}
-
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import java.nio.channels.Channel;
+import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
/**
* A file lock table that is over a system-wide map of all file locks.
*/
-class SharedFileLockTable extends FileLockTable {
-
+class FileLockTable {
/**
* A weak reference to a FileLock.
* <p>
- * SharedFileLockTable uses a list of file lock references to avoid keeping the
+ * FileLockTable uses a list of file lock references to avoid keeping the
* FileLock (and FileChannel) alive.
*/
private static class FileLockReference extends WeakReference<FileLock> {
@@ -118,14 +81,17 @@
// Locks obtained for this channel
private final Set<FileLock> locks;
- SharedFileLockTable(Channel channel, FileDescriptor fd) throws IOException {
+ /**
+ * Creates a file lock table for a channel that is connected to the
+ * system-wide map of all file locks for the Java virtual machine.
+ */
+ FileLockTable(Channel channel, FileDescriptor fd) throws IOException {
this.channel = channel;
this.fileKey = FileKey.create(fd);
this.locks = new HashSet<FileLock>();
}
- @Override
- public void add(FileLock fl) throws OverlappingFileLockException {
+ void add(FileLock fl) throws OverlappingFileLockException {
List<FileLockReference> list = lockMap.get(fileKey);
for (;;) {
@@ -176,8 +142,7 @@
}
}
- @Override
- public void remove(FileLock fl) {
+ void remove(FileLock fl) {
assert fl != null;
// the lock must exist so the list of locks must be present
@@ -201,8 +166,7 @@
}
}
- @Override
- public List<FileLock> removeAll() {
+ List<FileLock> removeAll() {
List<FileLock> result = new ArrayList<FileLock>();
List<FileLockReference> list = lockMap.get(fileKey);
if (list != null) {
@@ -234,8 +198,7 @@
return result;
}
- @Override
- public void replace(FileLock fromLock, FileLock toLock) {
+ void replace(FileLock fromLock, FileLock toLock) {
// the lock must exist so there must be a list
List<FileLockReference> list = lockMap.get(fileKey);
assert list != null;