Update RequestResponse codes

doc/protocol.md

@@ -31,26 +31,26 @@ All messages begins with `P2P-JAVA-PROJECT VERSION 1.0\n` (this version of the p
 - RESPONSES (msb is 1):
 	- `LIST` (0x80)
 	- `LOAD` (0x81)
-	- `NOT FOUND` (0x82)
-	- `PROTOCOL ERROR` (0x83)
-	- `INTERNAL ERROR` (0x84)
+	- `VERSION ERROR` (0xC0)
+	- `PROTOCOL ERROR` (0xC1)
+	- `INTERNAL ERROR` (0xC2)
+	- `EMPTY DIRECTORY` (0xC3)
+	- `NOT FOUND` (0xC4)
 
 ### List
 Payload size for list request is always zero.
-Payload for list response is filenames separated by `\n`.
+Payload for list response is filenames separated by `\n`. Payload size for list response is never zero.
+
+#### Empty directory
+When directory is empty.
+Payload size for empty directory is always zero.
+
 
 ### Load
 #### Not found
 Response when the file requested is not found on the server.
 Payload size for Not found is zero.
 
-#### Protocol error
-Response when the request cannot be interpreted.
-Payload size for Protocol error is zero
-
-#### Internal error
-Response in internal failure case.
-Payload size for Internal error is zero.
 
 #### Load response
 Payload contains
@@ -64,3 +64,15 @@ Payload contains
 
 #### Load request
 Payload contains only the name of the file to load.
+
+### Other response code (errors)
+#### Version error
+Response when datagram received use wrong version code.
+
+#### Protocol error
+Response when the request cannot be interpreted (but version is correct).
+Payload size for Protocol error is zero
+
+#### Internal error
+Response in internal failure case.
+Payload size for Internal error is zero.

src/exception/VersionError.java

@@ -0,0 +1,2 @@
+package exception;
+public class VersionError extends Exceptions {}

src/protocolP2P/CodeType.java

@@ -1,5 +1,6 @@
 package protocolP2P;
 public enum CodeType {
 	REQUEST,
-	RESPONSE
+	RESPONSE,
+	ERROR
 }

src/protocolP2P/FileList.java

@@ -3,6 +3,7 @@ import java.util.ArrayList;
 import protocolP2P.Payload;
 import protocolP2P.RequestResponseCode;
 import exception.ProtocolError;
+import exception.InternalError;
 
 public class FileList extends Payload {
 	private final static RequestResponseCode requestResponseCode = RequestResponseCode.LIST_RESPONSE;
@@ -12,9 +13,14 @@ public class FileList extends Payload {
 		this.content = content;
 	}
 
-	public FileList(byte[] datagram) throws ProtocolError {
+	public FileList(byte[] datagram) throws ProtocolError, InternalError {
 		//TODO
+		/* assert to help debugging */
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) == RequestResponseCode.LIST_RESPONSE : "FileList subclass is incompatible with this datagram, request/response code must be checked before using this constructor";
+		/* InternalErrorException */
+		if (RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LIST_RESPONSE) {
+			throw new InternalError();
+		}
 		int size = (datagram[PAYLOAD_SIZE_POSITON] << (8*3)) | (datagram[PAYLOAD_SIZE_POSITON+1] << (8*2)) | (datagram[PAYLOAD_SIZE_POSITON+2] << 8) | datagram[PAYLOAD_SIZE_POSITON+3];
 	
 	}

src/protocolP2P/FilePart.java

@@ -2,6 +2,7 @@ package protocolP2P;
 import protocolP2P.Payload;
 import protocolP2P.RequestResponseCode;
 import exception.ProtocolError;
+import exception.InternalError;
 
 public class FilePart extends Payload {
 	private static final RequestResponseCode requestResponseCode = RequestResponseCode.LOAD_RESPONSE;
@@ -17,9 +18,14 @@ public class FilePart extends Payload {
 		this.partialContent = partialContent;
 	}
 
-	public FilePart(byte[] datagram) throws ProtocolError {
+	public FilePart(byte[] datagram) throws ProtocolError, InternalError {
 		//TODO
+		/* assert to help debugging */
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) == RequestResponseCode.LOAD_RESPONSE : "FilePart subclass is incompatible with this datagram, request/response code must be checked before using this constructor";
+		/* InternalErrorException */
+		if (RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LOAD_RESPONSE) {
+			throw new InternalError();
+		}
 		int size = (datagram[PAYLOAD_SIZE_POSITON] << (8*3)) | (datagram[PAYLOAD_SIZE_POSITON+1] << (8*2)) | (datagram[PAYLOAD_SIZE_POSITON+2] << 8) | datagram[PAYLOAD_SIZE_POSITON+3];
 	}
 

src/protocolP2P/Payload.java

@@ -3,6 +3,7 @@ import protocolP2P.RequestResponseCode;
 import protocolP2P.FilePart;
 import protocolP2P.FileList;
 import exception.ProtocolError;
+import exception.InternalError;
 
 public class Payload {
 	private RequestResponseCode requestResponseCode;
@@ -10,16 +11,27 @@ public class Payload {
 	protected final static int PAYLOAD_START_POSITION = 8;
 
 	/** To create request/response with a payload size of zero */
-	public Payload(RequestResponseCode requestResponseCode) {
+	public Payload(RequestResponseCode requestResponseCode) throws InternalError {
+		/* asserts to help debugging */
 		assert requestResponseCode != requestResponseCode.LIST_RESPONSE : "LIST_RESPONSE must use FilePart class";
 		assert requestResponseCode != requestResponseCode.LOAD_RESPONSE : "LOAD_RESPONSE must use FileList class";
 		this.requestResponseCode = requestResponseCode;
+		checkRequestResponseCode(); // this can throw InternalError
 	}
 
-	public Payload(byte[] datagram) throws ProtocolError {
+	public Payload(byte[] datagram) throws ProtocolError, InternalError {
+		/* asserts to help debugging */
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LIST_RESPONSE : "LIST_RESPONSE must use FilePart class";
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LOAD_RESPONSE : "LOAD_RESPONSE must use FileList class";
 		requestResponseCode = RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]);
+		checkRequestResponseCode(); // this can throw InternalError
+	}
+
+	private void checkRequestResponseCode() throws InternalError {
+		/* Incorrect use cases (use subclasses instead) */
+		if (requestResponseCode == RequestResponseCode.LIST_RESPONSE || requestResponseCode == RequestResponseCode.LOAD_RESPONSE) {
+			throw new InternalError();
+		}
 	}
 	
 	/** Payload with padding */

src/protocolP2P/ProtocolP2PDatagram.java

@@ -1,5 +1,6 @@
 package protocolP2P;
 import exception.ProtocolError;
+import exception.VersionError;
 import protocolP2P.Payload;
 import protocolP2P.RequestResponseCode;
 import java.util.ArrayList;
@@ -16,10 +17,10 @@ public class ProtocolP2PDatagram {
 		this.payload = payload;
 	}
 
-	public ProtocolP2PDatagram(byte[] datagram) throws ProtocolError {
+	public ProtocolP2PDatagram(byte[] datagram) throws ProtocolError, VersionError {
 		// unwrap version
 		version = datagram[VERSION_POSITON];
-		checkProtocolVersion(); // this can throw ProtocolError
+		checkProtocolVersion(); // this can throw VersionError
 		RequestResponseCode r = RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]); // this can throw ProtocolError
 		switch (r) {
 			case RequestResponseCode.LIST_RESPONSE:
@@ -44,9 +45,9 @@ public class ProtocolP2PDatagram {
 		return payload;
 	}
 
-	private void checkProtocolVersion() throws ProtocolError {
+	private void checkProtocolVersion() throws VersionError {
 		if (PROTOCOL_VERSION != version) {
-			throw new ProtocolError();
+			throw new VersionError();
 		}
 	}
 }

src/protocolP2P/RequestResponseCode.java

@@ -16,9 +16,11 @@ public enum RequestResponseCode {
 	LOAD_REQUEST(CodeType.REQUEST, (byte)0x01),
 	LIST_RESPONSE(CodeType.RESPONSE, (byte)0x80),
 	LOAD_RESPONSE(CodeType.RESPONSE, (byte)0x81),
-	NOT_FOUND(CodeType.RESPONSE, (byte)0x82),
-	PROTOCOL_ERROR(CodeType.RESPONSE, (byte)0x83),
-	INTERNAL_ERROR(CodeType.RESPONSE, (byte)0x84);
+	VERSION_ERROR(CodeType.ERROR, (byte)0xC0),
+	PROTOCOL_ERROR(CodeType.ERROR, (byte)0xC1),
+	INTERNAL_ERROR(CodeType.ERROR, (byte)0xC2),
+	EMPTY_DIRECTORY(CodeType.ERROR, (byte)0xC3),
+	NOT_FOUND(CodeType.ERROR, (byte)0xC4);
 	
 	public final CodeType codeType;
 	public final byte codeValue;