Submit recent changes from internal branch, including "lite mode" for

C++ and Java.  See CHANGES.txt for more details.

1 files changed, 194 insertions, 0 deletions

diff --git a/java/src/main/java/com/google/protobuf/Internal.java b/java/src/main/java/com/google/protobuf/Internal.java
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+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.io.UnsupportedEncodingException;
+
+/**
+ * The classes contained within are used internally by the Protocol Buffer
+ * library and generated message implementations. They are public only because
+ * those generated messages do not reside in the {@code protobuf} package.
+ * Others should not use this class directly.
+ *
+ * @author cyrusn@google.com (Cyrus Najmabadi)
+ */
+public class Internal {
+  /**
+   * Implementation of a Queue designed to have as little overhead as possible.
+   * No guarantees are made as to the order you will get values back from the
+   * queue. Currently it is a Last-In-First-Out implementation, but that may
+   * change in the future.
+   *
+   * Duplicate values are allowed, as are null values.
+   *
+   * Not threadsafe.
+   *
+   * @author cyrusn@google.com (Cyrus Najmabadi)
+   */
+  public static final class QuickQueue<T> {
+    @SuppressWarnings("unchecked")
+    private T[] array = (T[]) new Object[16];
+    private int size;
+
+    /**
+     * Adds a value to the queue.
+     *
+     * @param value The value to add to the queue.
+     */
+    public void offer(final T value) {
+      if (size == array.length) {
+        // I'd like to use Arrays.copy here. However, it is currently
+        // unavailable
+        // on android. So, for now, we just use the tried and true arraycopy
+        // technique.
+        @SuppressWarnings("unchecked")
+        final T[] copy = (T[]) new Object[size * 2];
+        System.arraycopy(array, 0, copy, 0, array.length);
+        array = copy;
+      }
+
+      array[size++] = value;
+    }
+
+    /**
+     * Removes some previously added value to the queue, or {@code null} if the
+     * queue is empty.
+     *
+     * @return An existing value in the queue, or {@code null} if the queue is
+     *         empty.
+     */
+    public T poll() {
+      if (size == 0) {
+        return null;
+      }
+
+      final T result = array[--size];
+      // make sure we null out the entry so that we're not keeping anything
+      // alive unnecessarily.
+      array[size] = null;
+
+      return result;
+    }
+  }
+
+  /**
+   * Instances of this class will provide a unique {@code QuickQueue} to each
+   * thread that accesses it. Very useful for providing free lists without
+   * needing to take any locks.
+   *
+   * @author cyrusn@google.com (Cyrus Najmabadi)
+   */
+  public static final class ThreadLocalQuickQueue<T>
+      extends ThreadLocal<QuickQueue<T>> {
+    @Override
+    protected QuickQueue<T> initialValue() {
+      return new QuickQueue<T>();
+    }
+  }
+
+  /**
+   * Helper called by generated code to construct default values for string
+   * fields.
+   * <p>
+   * The protocol compiler does not actually contain a UTF-8 decoder -- it
+   * just pushes UTF-8-encoded text around without touching it.  The one place
+   * where this presents a problem is when generating Java string literals.
+   * Unicode characters in the string literal would normally need to be encoded
+   * using a Unicode escape sequence, which would require decoding them.
+   * To get around this, protoc instead embeds the UTF-8 bytes into the
+   * generated code and leaves it to the runtime library to decode them.
+   * <p>
+   * It gets worse, though.  If protoc just generated a byte array, like:
+   *   new byte[] {0x12, 0x34, 0x56, 0x78}
+   * Java actually generates *code* which allocates an array and then fills
+   * in each value.  This is much less efficient than just embedding the bytes
+   * directly into the bytecode.  To get around this, we need another
+   * work-around.  String literals are embedded directly, so protoc actually
+   * generates a string literal corresponding to the bytes.  The easiest way
+   * to do this is to use the ISO-8859-1 character set, which corresponds to
+   * the first 256 characters of the Unicode range.  Protoc can then use
+   * good old CEscape to generate the string.
+   * <p>
+   * So we have a string literal which represents a set of bytes which
+   * represents another string.  This function -- stringDefaultValue --
+   * converts from the generated string to the string we actually want.  The
+   * generated code calls this automatically.
+   */
+  public static String stringDefaultValue(String bytes) {
+    try {
+      return new String(bytes.getBytes("ISO-8859-1"), "UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      // This should never happen since all JVMs are required to implement
+      // both of the above character sets.
+      throw new IllegalStateException(
+          "Java VM does not support a standard character set.", e);
+    }
+  }
+
+  /**
+   * Helper called by generated code to construct default values for bytes
+   * fields.
+   * <p>
+   * This is a lot like {@link #stringDefaultValue}, but for bytes fields.
+   * In this case we only need the second of the two hacks -- allowing us to
+   * embed raw bytes as a string literal with ISO-8859-1 encoding.
+   */
+  public static ByteString bytesDefaultValue(String bytes) {
+    try {
+      return ByteString.copyFrom(bytes.getBytes("ISO-8859-1"));
+    } catch (UnsupportedEncodingException e) {
+      // This should never happen since all JVMs are required to implement
+      // ISO-8859-1.
+      throw new IllegalStateException(
+          "Java VM does not support a standard character set.", e);
+    }
+  }
+
+  /**
+   * Interface for an enum value or value descriptor, to be used in FieldSet.
+   * The lite library stores enum values directly in FieldSets but the full
+   * library stores EnumValueDescriptors in order to better support reflection.
+   */
+  public interface EnumLite {
+    int getNumber();
+  }
+
+  /**
+   * Interface for an object which maps integers to {@link EnumLite}s.
+   * {@link Descriptors.EnumDescriptor} implements this interface by mapping
+   * numbers to {@link Descriptors.EnumValueDescriptor}s.  Additionally,
+   * every generated enum type has a static method internalGetValueMap() which
+   * returns an implementation of this type that maps numbers to enum values.
+   */
+  public interface EnumLiteMap<T extends EnumLite> {
+    T findValueByNumber(int number);
+  }
+}