| // Protocol Buffers - Google's data interchange format |
| // Copyright 2008 Google Inc. All rights reserved. |
| // https://developers.google.com/protocol-buffers/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| package com.google.protobuf; |
| |
| import sun.misc.Unsafe; |
| |
| import java.lang.reflect.Field; |
| import java.nio.Buffer; |
| import java.nio.ByteBuffer; |
| import java.security.AccessController; |
| import java.security.PrivilegedExceptionAction; |
| |
| /** |
| * Utility class for working with unsafe operations. |
| */ |
| // TODO(nathanmittler): Add support for Android Memory/MemoryBlock |
| final class UnsafeUtil { |
| private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
| private static final boolean HAS_UNSAFE_BYTEBUFFER_OPERATIONS = |
| supportsUnsafeByteBufferOperations(); |
| private static final boolean HAS_UNSAFE_ARRAY_OPERATIONS = supportsUnsafeArrayOperations(); |
| private static final long ARRAY_BASE_OFFSET = byteArrayBaseOffset(); |
| private static final long BUFFER_ADDRESS_OFFSET = fieldOffset(field(Buffer.class, "address")); |
| |
| private UnsafeUtil() { |
| } |
| |
| static boolean hasUnsafeArrayOperations() { |
| return HAS_UNSAFE_ARRAY_OPERATIONS; |
| } |
| |
| static boolean hasUnsafeByteBufferOperations() { |
| return HAS_UNSAFE_BYTEBUFFER_OPERATIONS; |
| } |
| |
| static long getArrayBaseOffset() { |
| return ARRAY_BASE_OFFSET; |
| } |
| |
| static byte getByte(byte[] target, long offset) { |
| return UNSAFE.getByte(target, offset); |
| } |
| |
| static void putByte(byte[] target, long offset, byte value) { |
| UNSAFE.putByte(target, offset, value); |
| } |
| |
| static void copyMemory( |
| byte[] src, long srcOffset, byte[] target, long targetOffset, long length) { |
| UNSAFE.copyMemory(src, srcOffset, target, targetOffset, length); |
| } |
| |
| static long getLong(byte[] target, long offset) { |
| return UNSAFE.getLong(target, offset); |
| } |
| |
| static byte getByte(long address) { |
| return UNSAFE.getByte(address); |
| } |
| |
| static void putByte(long address, byte value) { |
| UNSAFE.putByte(address, value); |
| } |
| |
| static long getLong(long address) { |
| return UNSAFE.getLong(address); |
| } |
| |
| static void copyMemory(long srcAddress, long targetAddress, long length) { |
| UNSAFE.copyMemory(srcAddress, targetAddress, length); |
| } |
| |
| /** |
| * Gets the offset of the {@code address} field of the given direct {@link ByteBuffer}. |
| */ |
| static long addressOffset(ByteBuffer buffer) { |
| return UNSAFE.getLong(buffer, BUFFER_ADDRESS_OFFSET); |
| } |
| |
| /** |
| * Gets the {@code sun.misc.Unsafe} instance, or {@code null} if not available on this platform. |
| */ |
| private static sun.misc.Unsafe getUnsafe() { |
| sun.misc.Unsafe unsafe = null; |
| try { |
| unsafe = |
| AccessController.doPrivileged( |
| new PrivilegedExceptionAction<Unsafe>() { |
| @Override |
| public sun.misc.Unsafe run() throws Exception { |
| Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class; |
| |
| for (Field f : k.getDeclaredFields()) { |
| f.setAccessible(true); |
| Object x = f.get(null); |
| if (k.isInstance(x)) { |
| return k.cast(x); |
| } |
| } |
| // The sun.misc.Unsafe field does not exist. |
| return null; |
| } |
| }); |
| } catch (Throwable e) { |
| // Catching Throwable here due to the fact that Google AppEngine raises NoClassDefFoundError |
| // for Unsafe. |
| } |
| return unsafe; |
| } |
| |
| /** |
| * Indicates whether or not unsafe array operations are supported on this platform. |
| */ |
| private static boolean supportsUnsafeArrayOperations() { |
| boolean supported = false; |
| if (UNSAFE != null) { |
| try { |
| Class<?> clazz = UNSAFE.getClass(); |
| clazz.getMethod("arrayBaseOffset", Class.class); |
| clazz.getMethod("getByte", Object.class, long.class); |
| clazz.getMethod("putByte", Object.class, long.class, byte.class); |
| clazz.getMethod("getLong", Object.class, long.class); |
| clazz.getMethod( |
| "copyMemory", Object.class, long.class, Object.class, long.class, long.class); |
| supported = true; |
| } catch (Throwable e) { |
| // Do nothing. |
| } |
| } |
| return supported; |
| } |
| |
| private static boolean supportsUnsafeByteBufferOperations() { |
| boolean supported = false; |
| if (UNSAFE != null) { |
| try { |
| Class<?> clazz = UNSAFE.getClass(); |
| clazz.getMethod("objectFieldOffset", Field.class); |
| clazz.getMethod("getByte", long.class); |
| clazz.getMethod("getLong", Object.class, long.class); |
| clazz.getMethod("putByte", long.class, byte.class); |
| clazz.getMethod("getLong", long.class); |
| clazz.getMethod("copyMemory", long.class, long.class, long.class); |
| supported = true; |
| } catch (Throwable e) { |
| // Do nothing. |
| } |
| } |
| return supported; |
| } |
| |
| /** |
| * Get the base offset for byte arrays, or {@code -1} if {@code sun.misc.Unsafe} is not available. |
| */ |
| private static int byteArrayBaseOffset() { |
| return HAS_UNSAFE_ARRAY_OPERATIONS ? UNSAFE.arrayBaseOffset(byte[].class) : -1; |
| } |
| |
| /** |
| * Returns the offset of the provided field, or {@code -1} if {@code sun.misc.Unsafe} is not |
| * available. |
| */ |
| private static long fieldOffset(Field field) { |
| return field == null || UNSAFE == null ? -1 : UNSAFE.objectFieldOffset(field); |
| } |
| |
| /** |
| * Gets the field with the given name within the class, or {@code null} if not found. If found, |
| * the field is made accessible. |
| */ |
| private static Field field(Class<?> clazz, String fieldName) { |
| Field field; |
| try { |
| field = clazz.getDeclaredField(fieldName); |
| field.setAccessible(true); |
| } catch (Throwable t) { |
| // Failed to access the fields. |
| field = null; |
| } |
| return field; |
| } |
| } |