package com.alibaba.otter.canal.parse.driver.mysql.utils;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import com.alibaba.otter.canal.parse.driver.mysql.packets.HeaderPacket;
public abstract class PacketManager {
public static HeaderPacket readHeader(SocketChannel ch, int len) throws IOException {
HeaderPacket header = new HeaderPacket();
header.fromBytes(readBytesAsBuffer(ch, len).array());
return header;
}
public static ByteBuffer readBytesAsBuffer(SocketChannel ch, int len) throws IOException {
ByteBuffer buffer = ByteBuffer.allocate(len);
while (buffer.hasRemaining()) {
int readNum = ch.read(buffer);
if (readNum == -1) {
throw new IOException("Unexpected End Stream");
}
}
return buffer;
}
public static byte[] readBytes(SocketChannel ch, int len) throws IOException {
return readBytesAsBuffer(ch, len).array();
}
/**
* Since We r using blocking IO, so we will just write once and assert the length to simplify the read operation.<br>
* If the block write doesn't work as we expected, we will change this implementation as per the result.
*
* @param ch
* @param len
* @return
* @throws IOException
*/
public static void write(SocketChannel ch, ByteBuffer[] srcs) throws IOException {
@SuppressWarnings("unused")
long total = 0;
for (ByteBuffer buffer : srcs) {
total += buffer.remaining();
}
ch.write(srcs);
// https://github.com/alibaba/canal/issues/24
// 部分windows用户会出现size != total的情况，jdk为java7/openjdk，估计和java版本有关，暂时不做检查
// long size = ch.write(srcs);
// if (size != total) {
// throw new IOException("unexpected blocking io behavior");
// }
}
public static void write(SocketChannel ch, byte[] body) throws IOException {
write(ch, body, (byte) 0);
}
public static void write(SocketChannel ch, byte[] body, byte packetSeqNumber) throws IOException {
HeaderPacket header = new HeaderPacket();
header.setPacketBodyLength(body.length);
header.setPacketSequenceNumber(packetSeqNumber);
write(ch, new ByteBuffer[] { ByteBuffer.wrap(header.toBytes()), ByteBuffer.wrap(body) });
}
}