/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package com.facebook.presto.jdbc.internal.netty.handler.codec.base64;
import com.facebook.presto.jdbc.internal.netty.buffer.ChannelBuffer;
import com.facebook.presto.jdbc.internal.netty.buffer.ChannelBuffers;
import com.facebook.presto.jdbc.internal.netty.channel.Channel;
import com.facebook.presto.jdbc.internal.netty.channel.ChannelHandler.Sharable;
import com.facebook.presto.jdbc.internal.netty.channel.ChannelHandlerContext;
import com.facebook.presto.jdbc.internal.netty.channel.ChannelPipeline;
import com.facebook.presto.jdbc.internal.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
import com.facebook.presto.jdbc.internal.netty.handler.codec.frame.Delimiters;
import com.facebook.presto.jdbc.internal.netty.handler.codec.frame.FrameDecoder;
import com.facebook.presto.jdbc.internal.netty.handler.codec.oneone.OneToOneDecoder;
import com.facebook.presto.jdbc.internal.netty.util.CharsetUtil;
/**
* Decodes a Base64-encoded {@link ChannelBuffer} or US-ASCII {@link String}
* into a {@link ChannelBuffer}. Please note that this decoder must be used
* with a proper {@link FrameDecoder} such as {@link DelimiterBasedFrameDecoder}
* if you are using a stream-based transport such as TCP/IP. A typical decoder
* setup for TCP/IP would be:
* <pre>
* {@link ChannelPipeline} pipeline = ...;
*
* // Decoders
* pipeline.addLast("frameDecoder", new {@link DelimiterBasedFrameDecoder}(80, {@link Delimiters#nulDelimiter()}));
* pipeline.addLast("base64Decoder", new {@link Base64Decoder}());
*
* // Encoder
* pipeline.addLast("base64Encoder", new {@link Base64Encoder}());
* </pre>
* @apiviz.landmark
* @apiviz.uses com.facebook.presto.jdbc.internal.netty.handler.codec.base64.Base64
*/
@Sharable
public class Base64Decoder extends OneToOneDecoder {
private final Base64Dialect dialect;
public Base64Decoder() {
this(Base64Dialect.STANDARD);
}
public Base64Decoder(Base64Dialect dialect) {
if (dialect == null) {
throw new NullPointerException("dialect");
}
this.dialect = dialect;
}
@Override
protected Object decode(ChannelHandlerContext ctx, Channel channel, Object msg)
throws Exception {
if (msg instanceof String) {
msg = ChannelBuffers.copiedBuffer((String) msg, CharsetUtil.US_ASCII);
} else if (!(msg instanceof ChannelBuffer)) {
return msg;
}
ChannelBuffer src = (ChannelBuffer) msg;
return Base64.decode(
src, src.readerIndex(), src.readableBytes(), dialect);
}
}