1 files changed, 114 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/fs4/Packet.java b/container-search/src/main/java/com/yahoo/fs4/Packet.java
new file mode 100644
index 00000000000..1e9deede59d
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/fs4/Packet.java
@@ -0,0 +1,114 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.fs4;
+
+import java.nio.ByteBuffer;
+import java.util.logging.Logger;
+
+/**
+ * Superclass of fs4 packets containing channel/query ID
+ *
+ * @author bratseth
+ */
+public abstract class Packet extends BasicPacket {
+
+    private static Logger log = Logger.getLogger(Packet.class.getName());
+
+    /**
+     * The channel at which this packet will be sent or was received,
+     * or -1 when this is not known
+     */
+    protected int channel = -1;
+
+    /**
+     * Fills this package from a byte buffer positioned at the first
+     * byte of the package
+     *
+     * @return this Packet (as a BasicPacket) for convenience
+     * @throws UnsupportedOperationException if not implemented in the subclass
+     */
+    public BasicPacket decode(ByteBuffer buffer) {
+        int originalPos = buffer.position();
+        length = buffer.getInt()+4; // Streamed packet length is the length-4
+        int packetLength = length;
+        try {
+            int code = buffer.getInt();
+            channel = buffer.getInt();
+
+            decodeAndDecompressBody(buffer, code, length - 3*4);
+        }
+        finally {
+            int targetPosition = (originalPos + packetLength);
+            if (buffer.position() != targetPosition) {
+                log.warning("Position in buffer is " + buffer.position() + " should be " + targetPosition);
+                buffer.position(targetPosition);
+            }
+        }
+
+        return this;
+    }
+
+    /**
+     * <p>Encodes this package onto the given buffer at the current
+     * position.  The position of the buffer after encoding is the
+     * byte following the last encoded byte.</p>
+     *
+     * <p>This method will ensure that everything is written provided
+     * sufficient capacity regardless of the buffer limit.
+     * When returning, the limit is at the end of the package (qual to the
+     * position).</p>
+     *
+     * @return this for convenience
+     * @throws UnsupportedOperationException if not implemented in the subclass
+     */
+    public final Packet encode(ByteBuffer buffer, int channel) throws BufferTooSmallException {
+        this.channel = channel;
+        int oldLimit = buffer.limit();
+        int startPosition = buffer.position();
+
+        buffer.limit(buffer.capacity());
+        try {
+            buffer.putInt(8); // Real length written later, when we know it
+            buffer.putInt(getCode());
+            buffer.putInt(channel);
+
+            encodeAndCompressBody(buffer, startPosition);
+        }
+        catch (java.nio.BufferOverflowException e) {
+            // reset buffer to expected state
+            buffer.position(startPosition);
+            buffer.limit(oldLimit);
+            throw new BufferTooSmallException("Destination buffer too small while encoding packet");
+        }
+        return this;
+    }
+
+    /**
+     * Get the channel id of the packet.  In the FS4 transport protocol,
+     * there is the concept of a channel.  This must <b>not</b> be confused
+     * with all the other channels we have floating around this code (aargh!).
+     * <P>
+     * The channel can be thought of as a way to pair up requests and
+     * responses in the FS4 protocol:  A response always belongs to
+     * to a channel and it is the clients responsibility to not re-use
+     * channel ids within the same connection.
+     * <p>
+     * Summary: This "channel" means "session id"
+     *
+     * @return FS4 channel id
+     *
+     */
+    public int getChannel() { return channel; }
+
+    public void setChannel(int channel) { this.channel=channel; }
+
+
+    /** Informs that this packets needs a channel ID. */
+    public boolean hasChannelId() {
+        return true;
+    }
+
+    public String toString() {
+        return "packet with code " + getCode() + ", channelId=" + getChannel();
+    }
+
+}