third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeUtil.java

+// 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 java.lang.reflect.Field;
+import java.nio.Buffer;
+import java.nio.ByteBuffer;
+import java.security.AccessController;
+import java.security.PrivilegedExceptionAction;
+import sun.misc.Unsafe;
+
+/** 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 Object allocateInstance(Class<?> clazz) {
+    try {
+      return UNSAFE.allocateInstance(clazz);
+    } catch (InstantiationException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  static long objectFieldOffset(Field field) {
+    return UNSAFE.objectFieldOffset(field);
+  }
+
+  static long getArrayBaseOffset() {
+    return ARRAY_BASE_OFFSET;
+  }
+
+  static byte getByte(Object target, long offset) {
+    return UNSAFE.getByte(target, offset);
+  }
+
+  static void putByte(Object target, long offset, byte value) {
+    UNSAFE.putByte(target, offset, value);
+  }
+
+  static int getInt(Object target, long offset) {
+    return UNSAFE.getInt(target, offset);
+  }
+
+  static void putInt(Object target, long offset, int value) {
+    UNSAFE.putInt(target, offset, value);
+  }
+
+  static long getLong(Object target, long offset) {
+    return UNSAFE.getLong(target, offset);
+  }
+
+  static void putLong(Object target, long offset, long value) {
+    UNSAFE.putLong(target, offset, value);
+  }
+
+  static boolean getBoolean(Object target, long offset) {
+    return UNSAFE.getBoolean(target, offset);
+  }
+
+  static void putBoolean(Object target, long offset, boolean value) {
+    UNSAFE.putBoolean(target, offset, value);
+  }
+
+  static float getFloat(Object target, long offset) {
+    return UNSAFE.getFloat(target, offset);
+  }
+
+  static void putFloat(Object target, long offset, float value) {
+    UNSAFE.putFloat(target, offset, value);
+  }
+
+  static double getDouble(Object target, long offset) {
+    return UNSAFE.getDouble(target, offset);
+  }
+
+  static void putDouble(Object target, long offset, double value) {
+    UNSAFE.putDouble(target, offset, value);
+  }
+
+  static Object getObject(Object target, long offset) {
+    return UNSAFE.getObject(target, offset);
+  }
+
+  static void putObject(Object target, long offset, Object value) {
+    UNSAFE.putObject(target, offset, value);
+  }
+
+  static void copyMemory(
+      Object src, long srcOffset, Object target, long targetOffset, long length) {
+    UNSAFE.copyMemory(src, srcOffset, target, targetOffset, length);
+  }
+
+  static byte getByte(long address) {
+    return UNSAFE.getByte(address);
+  }
+
+  static void putByte(long address, byte value) {
+    UNSAFE.putByte(address, value);
+  }
+
+  static int getInt(long address) {
+    return UNSAFE.getInt(address);
+  }
+
+  static void putInt(long address, int value) {
+    UNSAFE.putInt(address, value);
+  }
+
+  static long getLong(long address) {
+    return UNSAFE.getLong(address);
+  }
+
+  static void putLong(long address, long value) {
+    UNSAFE.putLong(address, value);
+  }
+
+  static void copyMemory(long srcAddress, long targetAddress, long length) {
+    UNSAFE.copyMemory(srcAddress, targetAddress, length);
+  }
+
+  static void setMemory(long address, long numBytes, byte value) {
+    UNSAFE.setMemory(address, numBytes, value);
+  }
+
+  /**
+   * 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("objectFieldOffset", Field.class);
+        clazz.getMethod("allocateInstance", Class.class);
+        clazz.getMethod("arrayBaseOffset", Class.class);
+        clazz.getMethod("getByte", Object.class, long.class);
+        clazz.getMethod("putByte", Object.class, long.class, byte.class);
+        clazz.getMethod("getBoolean", Object.class, long.class);
+        clazz.getMethod("putBoolean", Object.class, long.class, boolean.class);
+        clazz.getMethod("getInt", Object.class, long.class);
+        clazz.getMethod("putInt", Object.class, long.class, int.class);
+        clazz.getMethod("getLong", Object.class, long.class);
+        clazz.getMethod("putLong", Object.class, long.class, long.class);
+        clazz.getMethod("getFloat", Object.class, long.class);
+        clazz.getMethod("putFloat", Object.class, long.class, float.class);
+        clazz.getMethod("getDouble", Object.class, long.class);
+        clazz.getMethod("putDouble", Object.class, long.class, double.class);
+        clazz.getMethod("getObject", Object.class, long.class);
+        clazz.getMethod("putObject", Object.class, long.class, Object.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();
+        // Methods for getting direct buffer address.
+        clazz.getMethod("objectFieldOffset", Field.class);
+        clazz.getMethod("getLong", Object.class, long.class);
+
+        clazz.getMethod("getByte", long.class);
+        clazz.getMethod("putByte", long.class, byte.class);
+        clazz.getMethod("getInt", long.class);
+        clazz.getMethod("putInt", long.class, int.class);
+        clazz.getMethod("getLong", long.class);
+        clazz.getMethod("putLong", long.class, long.class);
+        clazz.getMethod("setMemory", long.class, long.class, byte.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;
+  }
+}