115 lines
4.4 KiB
Java
115 lines
4.4 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.tomcat.websocket;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.util.List;
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import javax.websocket.Extension;
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/**
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* The internal representation of the transformation that a WebSocket extension
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* performs on a message.
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*/
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public interface Transformation {
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/**
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* Sets the next transformation in the pipeline.
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* @param t The next transformation
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*/
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void setNext(Transformation t);
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/**
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* Validate that the RSV bit(s) required by this transformation are not
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* being used by another extension. The implementation is expected to set
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* any bits it requires before passing the set of in-use bits to the next
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* transformation.
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*
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* @param i The RSV bits marked as in use so far as an int in the
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* range zero to seven with RSV1 as the MSB and RSV3 as the
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* LSB
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*
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* @return <code>true</code> if the combination of RSV bits used by the
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* transformations in the pipeline do not conflict otherwise
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* <code>false</code>
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*/
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boolean validateRsvBits(int i);
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/**
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* Obtain the extension that describes the information to be returned to the
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* client.
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*
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* @return The extension information that describes the parameters that have
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* been agreed for this transformation
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*/
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Extension getExtensionResponse();
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/**
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* Obtain more input data.
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*
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* @param opCode The opcode for the frame currently being processed
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* @param fin Is this the final frame in this WebSocket message?
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* @param rsv The reserved bits for the frame currently being
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* processed
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* @param dest The buffer in which the data is to be written
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*
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* @return The result of trying to read more data from the transform
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*
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* @throws IOException If an I/O error occurs while reading data from the
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* transform
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*/
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TransformationResult getMoreData(byte opCode, boolean fin, int rsv, ByteBuffer dest) throws IOException;
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/**
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* Validates the RSV and opcode combination (assumed to have been extracted
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* from a WebSocket Frame) for this extension. The implementation is
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* expected to unset any RSV bits it has validated before passing the
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* remaining RSV bits to the next transformation in the pipeline.
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*
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* @param rsv The RSV bits received as an int in the range zero to
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* seven with RSV1 as the MSB and RSV3 as the LSB
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* @param opCode The opCode received
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*
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* @return <code>true</code> if the RSV is valid otherwise
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* <code>false</code>
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*/
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boolean validateRsv(int rsv, byte opCode);
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/**
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* Takes the provided list of messages, transforms them, passes the
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* transformed list on to the next transformation (if any) and then returns
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* the resulting list of message parts after all of the transformations have
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* been applied.
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*
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* @param messageParts The list of messages to be transformed
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*
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* @return The list of messages after this any any subsequent
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* transformations have been applied. The size of the returned list
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* may be bigger or smaller than the size of the input list
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*
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* @throws IOException If an error occurs during the transformation of the
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* message parts
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*/
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List<MessagePart> sendMessagePart(List<MessagePart> messageParts) throws IOException;
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/**
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* Clean-up any resources that were used by the transformation.
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*/
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void close();
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}
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