Make the fuchsia mojo/public repo the source of truth.

mojo/public/java/bindings/src/org/chromium/mojo/bindings/MessageHeader.java

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.mojo.bindings;
-
-import java.nio.ByteBuffer;
-
-/**
- * Header information for a message.
- */
-public class MessageHeader {
-
-    private static final int SIMPLE_MESSAGE_SIZE = 16;
-    private static final int SIMPLE_MESSAGE_VERSION = 0;
-    private static final DataHeader SIMPLE_MESSAGE_STRUCT_INFO =
-            new DataHeader(SIMPLE_MESSAGE_SIZE, SIMPLE_MESSAGE_VERSION);
-
-    private static final int MESSAGE_WITH_REQUEST_ID_SIZE = 24;
-    private static final int MESSAGE_WITH_REQUEST_ID_VERSION = 1;
-    private static final DataHeader MESSAGE_WITH_REQUEST_ID_STRUCT_INFO =
-            new DataHeader(MESSAGE_WITH_REQUEST_ID_SIZE, MESSAGE_WITH_REQUEST_ID_VERSION);
-
-    private static final int TYPE_OFFSET = 8;
-    private static final int FLAGS_OFFSET = 12;
-    private static final int REQUEST_ID_OFFSET = 16;
-
-    /**
-     * Flag for a header of a simple message.
-     */
-    public static final int NO_FLAG = 0;
-
-    /**
-     * Flag for a header of a message that expected a response.
-     */
-    public static final int MESSAGE_EXPECTS_RESPONSE_FLAG = 1 << 0;
-
-    /**
-     * Flag for a header of a message that is a response.
-     */
-    public static final int MESSAGE_IS_RESPONSE_FLAG = 1 << 1;
-
-    private final DataHeader mDataHeader;
-    private final int mType;
-    private final int mFlags;
-    private long mRequestId;
-
-    /**
-     * Constructor for the header of a message which does not have a response.
-     */
-    public MessageHeader(int type) {
-        mDataHeader = SIMPLE_MESSAGE_STRUCT_INFO;
-        mType = type;
-        mFlags = 0;
-        mRequestId = 0;
-    }
-
-    /**
-     * Constructor for the header of a message which have a response or being itself a response.
-     */
-    public MessageHeader(int type, int flags, long requestId) {
-        assert mustHaveRequestId(flags);
-        mDataHeader = MESSAGE_WITH_REQUEST_ID_STRUCT_INFO;
-        mType = type;
-        mFlags = flags;
-        mRequestId = requestId;
-    }
-
-    /**
-     * Constructor, parsing the header from a message. Should only be used by {@link Message}
-     * itself.
-     */
-    MessageHeader(Message message) {
-        Decoder decoder = new Decoder(message);
-        mDataHeader = decoder.readDataHeader();
-        validateDataHeader(mDataHeader);
-        mType = decoder.readInt(TYPE_OFFSET);
-        mFlags = decoder.readInt(FLAGS_OFFSET);
-        if (mustHaveRequestId(mFlags)) {
-            if (mDataHeader.size < MESSAGE_WITH_REQUEST_ID_SIZE) {
-                throw new DeserializationException("Incorrect message size, expecting at least "
-                        + MESSAGE_WITH_REQUEST_ID_SIZE
-                        + " for a message with a request identifier, but got: " + mDataHeader.size);
-
-            }
-            mRequestId = decoder.readLong(REQUEST_ID_OFFSET);
-        } else {
-            mRequestId = 0;
-        }
-    }
-
-    /**
-     * Returns the size in bytes of the serialization of the header.
-     */
-    public int getSize() {
-        return mDataHeader.size;
-    }
-
-    /**
-     * Returns the type of the message.
-     */
-    public int getType() {
-        return mType;
-    }
-
-    /**
-     * Returns the flags associated to the message.
-     */
-    public int getFlags() {
-        return mFlags;
-    }
-
-    /**
-     * Returns if the message has the given flag.
-     */
-    public boolean hasFlag(int flag) {
-        return (mFlags & flag) == flag;
-    }
-
-    /**
-     * Returns if the message has a request id.
-     */
-    public boolean hasRequestId() {
-        return mustHaveRequestId(mFlags);
-    }
-
-    /**
-     * Return the request id for the message. Must only be called if the message has a request id.
-     */
-    public long getRequestId() {
-        assert hasRequestId();
-        return mRequestId;
-    }
-
-    /**
-     * Encode the header.
-     */
-    public void encode(Encoder encoder) {
-        encoder.encode(mDataHeader);
-        encoder.encode(getType(), TYPE_OFFSET);
-        encoder.encode(getFlags(), FLAGS_OFFSET);
-        if (hasRequestId()) {
-            encoder.encode(getRequestId(), REQUEST_ID_OFFSET);
-        }
-    }
-
-    /**
-     * Returns true if the header has the expected flags. Only considers flags this class knows
-     * about in order to allow this class to work with future version of the header format.
-     */
-    public boolean validateHeader(int expectedFlags) {
-        int knownFlags = getFlags() & (MESSAGE_EXPECTS_RESPONSE_FLAG | MESSAGE_IS_RESPONSE_FLAG);
-        return knownFlags == expectedFlags;
-    }
-
-    /**
-     * Returns true if the header has the expected type and flags. Only consider flags this class
-     * knows about in order to allow this class to work with future version of the header format.
-     */
-    public boolean validateHeader(int expectedType, int expectedFlags) {
-        return getType() == expectedType && validateHeader(expectedFlags);
-    }
-
-    /**
-     * @see Object#hashCode()
-     */
-    @Override
-    public int hashCode() {
-        final int prime = 31;
-        int result = 1;
-        result = prime * result + ((mDataHeader == null) ? 0 : mDataHeader.hashCode());
-        result = prime * result + mFlags;
-        result = prime * result + (int) (mRequestId ^ (mRequestId >>> 32));
-        result = prime * result + mType;
-        return result;
-    }
-
-    /**
-     * @see Object#equals(Object)
-     */
-    @Override
-    public boolean equals(Object object) {
-        if (object == this) return true;
-        if (object == null) return false;
-        if (getClass() != object.getClass()) return false;
-
-        MessageHeader other = (MessageHeader) object;
-        return (BindingsHelper.equals(mDataHeader, other.mDataHeader)
-                && mFlags == other.mFlags
-                && mRequestId == other.mRequestId
-                && mType == other.mType);
-    }
-
-    /**
-     * Set the request id on the message contained in the given buffer.
-     */
-    void setRequestId(ByteBuffer buffer, long requestId) {
-        assert mustHaveRequestId(buffer.getInt(FLAGS_OFFSET));
-        buffer.putLong(REQUEST_ID_OFFSET, requestId);
-        mRequestId = requestId;
-    }
-
-    /**
-     * Returns whether a message with the given flags must have a request Id.
-     */
-    private static boolean mustHaveRequestId(int flags) {
-        return (flags & (MESSAGE_EXPECTS_RESPONSE_FLAG | MESSAGE_IS_RESPONSE_FLAG)) != 0;
-    }
-
-    /**
-     * Validate that the given {@link DataHeader} can be the data header of a message header.
-     */
-    private static void validateDataHeader(DataHeader dataHeader) {
-        if (dataHeader.elementsOrVersion < SIMPLE_MESSAGE_VERSION) {
-            throw new DeserializationException("Incorrect number of fields, expecting at least "
-                    + SIMPLE_MESSAGE_VERSION + ", but got: " + dataHeader.elementsOrVersion);
-        }
-        if (dataHeader.size < SIMPLE_MESSAGE_SIZE) {
-            throw new DeserializationException(
-                    "Incorrect message size, expecting at least " + SIMPLE_MESSAGE_SIZE
-                    + ", but got: " + dataHeader.size);
-        }
-        if (dataHeader.elementsOrVersion == SIMPLE_MESSAGE_VERSION
-                && dataHeader.size != SIMPLE_MESSAGE_SIZE) {
-            throw new DeserializationException("Incorrect message size for a message with "
-                    + SIMPLE_MESSAGE_VERSION + " fields, expecting " + SIMPLE_MESSAGE_SIZE
-                    + ", but got: " + dataHeader.size);
-        }
-        if (dataHeader.elementsOrVersion == MESSAGE_WITH_REQUEST_ID_VERSION
-                && dataHeader.size != MESSAGE_WITH_REQUEST_ID_SIZE) {
-            throw new DeserializationException("Incorrect message size for a message with "
-                    + MESSAGE_WITH_REQUEST_ID_VERSION + " fields, expecting "
-                    + MESSAGE_WITH_REQUEST_ID_SIZE + ", but got: " + dataHeader.size);
-        }
-    }
-
-}