Refactor: Moved network protocol implementation to de::Socket

The revised network protocol that supports deflated message payloads
was moved to libdeng2's de::Socket class.

Also cleaned up the implementation of de::Socket and removed the
now-unnecessary internal Doorman class (running under QApplication).

doomsday/engine/portable/include/protocol.h

@@ -26,9 +26,11 @@
 /// Largest message sendable using the protocol.
 #define PROTOCOL_MAX_DATAGRAM_SIZE (1 << 22) // 4 MB
 
+/*
 void Protocol_Init(void);
 
 void Protocol_Shutdown(void);
+*/
 
 /**
  * Send the data buffer over a TCP connection.

doomsday/engine/portable/src/protocol.c

@@ -17,55 +17,7 @@
  * 02110-1301 USA</small>
  */
 
-/**
- * @page sysNetwork Low-Level Networking
- *
- * On server-side connected clients can be either in "unjoined" mode or
- * "joined" mode. The former is for querying information about the server's
- * status, while the latter one is for clients participating in the on-going
- * game.
- *
- * Unjoined TCP sockets are periodically polled for activity
- * (N_ListenUnjoinedNodes()). Joined TCP sockets are handled in a separate
- * receiver thread (N_JoinedListenerThread()).
- *
- * @section netProtocol Network Protocol
- *
- * In joined mode, the network protocol works as follows. All messages are sent
- * over a TCP socket. Every message consists of a header and the message payload.
- * The content of these depends on the compressed message size.
- *
- * @par 1&ndash;127 bytes
- * Very small messages, such as the position updates that a client streams
- * to the server, are encoded with Huffman codes (see huffman.h). If
- * the Huffman coded payload happens to exceed 127 bytes, the message is
- * switched to the medium format (see below). Message structure:
- * - 1 byte: payload size
- * - @em n bytes: payload contents (Huffman)
- *
- * @par 128&ndash;4095 bytes
- * Medium-sized messages are compressed either using a fast zlib deflate level,
- * or Huffman codes if it yields better compression.
- * If the deflated message size exceeds 4095 bytes, the message is switched to
- * the large format (see below). Message structure:
- * - 1 byte: 0x80 | (payload size & 0x7f)
- * - 1 byte: (payload size >> 7) | (0x40 for deflated, otherwise Huffman)
- * - @em n bytes: payload contents (as produced by ZipFile_CompressAtLevel()).
- *
- * @par >= 4096 bytes (up to 4MB)
- * Large messages are compressed using the best zlib deflate level.
- * Message structure:
- * - 1 byte: 0x80 | (payload size & 0x7f)
- * - 1 byte: 0x80 | (payload size >> 7) & 0x7f
- * - 1 byte: payload size >> 14
- * - @em n bytes: payload contents (as produced by ZipFile_CompressAtLevel()).
- *
- * Messages larger than or equal to 2^22 bytes (about 4MB) must be broken into
- * smaller pieces before sending.
- *
- * @see Protocol_Send()
- * @see Protocol_Receive()
- */
+
 
 #include "de_base.h"
 #include "de_console.h"
@@ -77,23 +29,7 @@
 #include "huffman.h"
 #include "zipfile.h"
 
-#define MAX_SIZE_SMALL          127 // bytes
-#define MAX_SIZE_MEDIUM         4095 // bytes
-#define MAX_SIZE_LARGE          PROTOCOL_MAX_DATAGRAM_SIZE
-
-/// Threshold for input data size: messages smaller than this are first compressed
-/// with Doomsday's Huffman codes. If the result is smaller than the deflated data,
-/// the Huffman coded payload is used (unless it doesn't fit in a medium-sized packet).
-#define MAX_HUFFMAN_INPUT_SIZE  4096 // bytes
-
-#define DEFAULT_TRANSMISSION_SIZE   4096
-
-#define TRMF_CONTINUE           0x80
-#define TRMF_DEFLATED           0x40
-#define TRMF_SIZE_MASK          0x7f
-#define TRMF_SIZE_MASK_MEDIUM   0x3f
-#define TRMF_SIZE_SHIFT         7
-
+#if 0
 static byte* transmissionBuffer;
 static size_t transmissionBufferSize;
 
@@ -110,6 +46,7 @@ void Protocol_Shutdown(void)
     transmissionBuffer = NULL;
     transmissionBufferSize = 0;
 }
+#endif
 
 #if 0
 static boolean getBytesBlocking(TCPsocket sock, byte* buffer, size_t size)
@@ -155,10 +92,6 @@ boolean Protocol_Receive(nodeid_t from)
         msg->size = size;
         msg->handle = packet; // needs to be freed
 
-/*#ifdef _DEBUG
-        VERBOSE2(Con_Message("Protocol_Receive: Posting message, from=%i, size=%i\n", from, size));
-#endif*/
-
         // The message queue will handle the message from now on.
         N_PostMessage(msg);
     }
@@ -264,59 +197,22 @@ static void checkTransmissionBufferSize(size_t atLeastBytes)
     }
 }
 
-/**
- * Copies the message payload @a data to the transmission buffer.
- *
- * @param data  Data payload being send.
- * @param size  Size of the data payload.
- * @param needInflate  @c true, if the payload is deflated.
- */
-static size_t prepareTransmission(void* data, size_t size, boolean needInflate)
-{
-    Writer* msg = 0;
-    size_t msgSize = 0;
-
-    // The header is at most 3 bytes.
-    checkTransmissionBufferSize(size + 3);
-
-    // Compose the header and payload into the transmission buffer.
-    msg = Writer_NewWithBuffer(transmissionBuffer, transmissionBufferSize);
-
-    if(size <= MAX_SIZE_SMALL && !needInflate)
-    {
-        Writer_WriteByte(msg, size);
-    }
-    else if(size <= MAX_SIZE_MEDIUM)
-    {
-        Writer_WriteByte(msg, TRMF_CONTINUE | (size & TRMF_SIZE_MASK));
-        Writer_WriteByte(msg, (needInflate? TRMF_DEFLATED : 0) | (size >> TRMF_SIZE_SHIFT));
-    }
-    else if(size <= MAX_SIZE_LARGE)
-    {
-        assert(needInflate);
-        Writer_WriteByte(msg, TRMF_CONTINUE | (size & TRMF_SIZE_MASK));
-        Writer_WriteByte(msg, TRMF_CONTINUE | ((size >> TRMF_SIZE_SHIFT) & TRMF_SIZE_MASK));
-        Writer_WriteByte(msg, size >> (2*TRMF_SIZE_SHIFT));
-    }
-    else
-    {
-        // Not supported.
-        assert(false);
-    }
-
-    // The payload.
-    Writer_Write(msg, data, size);
-
-    msgSize = Writer_Size(msg);
-    Writer_Delete(msg);
-    return msgSize;
-}
 
 void Protocol_Send(void *data, size_t size, nodeid_t destination)
 {
     if(size == 0 || !N_GetNodeSocket(destination) || !N_HasNodeJoined(destination))
         return;
 
+    if(size > DDMAXINT)
+    {
+        Con_Error("Protocol_Send: Trying to send an oversized data buffer.\n"
+                  "  Attempted size is %u bytes.\n", (unsigned long) size);
+    }
+
+#ifdef _DEBUG
+    Monitor_Add(data, size);
+#endif
+
     LegacyNetwork_Send(N_GetNodeSocket(destination), data, size);
 
 #if 0

doomsday/libdeng2/include/de/legacy/legacynetwork.h

@@ -30,8 +30,8 @@ class Block;
 class IByteArray;
 
 /**
- * Network communications for the legacy engine implementation.
- * Implements simple socket networking for streaming blocks of data.
+ * Network communications for the legacy engine implementation. Implements
+ * simple socket networking for streaming blocks of data.
  *
  * There is a C wrapper for LegacyNetwork, @see c_wrapper.h
  */

doomsday/libdeng2/include/de/net/listensocket.h

@@ -23,7 +23,6 @@
 #include "../libdeng2.h"
 
 #include <QObject>
-#include <QTcpServer>
 #include <QList>
 #include <QThread>
 #include <QDebug>
@@ -68,7 +67,7 @@ class DENG2_PUBLIC ListenSocket : public QObject
     void incomingConnection();
 
 protected slots:
-    void acceptNewConnection(int handle);
+    void acceptNewConnection();
 
 private:
     struct Instance;

doomsday/libdeng2/include/de/net/socket.h

@@ -60,8 +60,8 @@ class DENG2_PUBLIC Socket : public QObject, public Transmitter
     /// The TCP/IP connection was disconnected. @ingroup errors
     DENG2_SUB_ERROR(BrokenError, DisconnectedError)
 
-    /// Incoming packet has an unknown block protocol. @ingroup errors
-    DENG2_SUB_ERROR(BrokenError, UnknownProtocolError)
+    /// Encountered a problem related to the messaging protocol. @ingroup errors
+    DENG2_SUB_ERROR(BrokenError, ProtocolError)
 
     /// There is no peer connected. @ingroup errors
     DENG2_SUB_ERROR(BrokenError, PeerError)
@@ -74,7 +74,17 @@ class DENG2_PUBLIC Socket : public QObject, public Transmitter
     Q_DECLARE_FLAGS(HeaderFlags, HeaderFlag)
 
 public:
-    Socket(const Address& address);
+    /**
+     * Opens a socket to @a address and waits (blocks) until the connection has
+     * been formed. The socket is ready to be used after the constructor
+     * returns. If the connection can be formed within the specified @a timeOut
+     * threshold, an exception is thrown.
+     *
+     * @param address  Address to connect to.
+     * @param timeOut  Maximum time to wait for connection.
+     */
+    Socket(const Address& address, const Time::Delta& timeOut = 5);
+
     virtual ~Socket();
 
     /**
@@ -171,16 +181,6 @@ private slots:
     void bytesWereWritten(qint64 bytes);
 
 protected:
-    /// Values for the transmission block header.
-    struct Header {
-        duint version;
-        bool huffman;
-        duint channel;
-        duint size;
-
-        Header();
-    };
-
     /// Create a Socket object for a previously opened socket.
     Socket(QTcpSocket* existingSocket);
 
@@ -195,10 +195,6 @@ private slots:
 
     void send(const IByteArray& packet, duint channel);
 
-    duint32 packHeader(const Header& header);
-
-    void unpackHeader(duint32 headerBytes, Header& header);
-
 private:
     struct Instance;
     Instance* d;

doomsday/libdeng2/network.pri

@@ -13,8 +13,7 @@ HEADERS += \
     include/de/net/transmitter.h \
 
 # Private headers.
-HEADERS += \
-    src/net/doorman.h
+HEADERS +=
 
 SOURCES += \
     src/net/address.cpp \

doomsday/libdeng2/src/net/listensocket.cpp

@@ -20,13 +20,14 @@
 #include "de/ListenSocket"
 #include "de/Address"
 #include "de/Socket"
-#include "doorman.h"
 
 #include <QCoreApplication>
+#include <QTcpServer>
 #include <QThread>
 
 using namespace de;
 
+/*
 void internal::Doorman::run()
 {
     _socket = new internal::TcpServer;
@@ -42,21 +43,24 @@ void internal::Doorman::run()
 
     delete _socket;
 }
+*/
 
 struct ListenSocket::Instance
 {
+#if 0
     /// Pointer to the internal socket data.
     internal::Doorman* doorman;
+#endif
 
+    QTcpServer* socket;
     duint16 port;
 
     /// Incoming connections.
     QList<int> incoming;
 
-    Instance() : doorman(0), port(0) {}
+    Instance() : socket(0), port(0) {}
     ~Instance() {
-        doorman->stopAndWait();
-        delete doorman;
+        delete socket;
     }
 };
 
@@ -65,33 +69,33 @@ ListenSocket::ListenSocket(duint16 port)
     LOG_AS("ListenSocket");
 
     d = new Instance;
-
+/*
     d->doorman = new internal::Doorman(port);
     connect(d->doorman, SIGNAL(incomingSocketDesc(int)), this, SLOT(acceptNewConnection(int)));
 
     d->doorman->start();
+*/
 
-/*    if(!d->socket->listen(QHostAddress::Any, d->port))
+    if(!d->socket->listen(QHostAddress::Any, d->port))
     {
         /// @throw OpenError Opening the socket failed.
         throw OpenError("ListenSocket", "Port " + QString::number(d->port) + ": " +
                         d->socket->errorString());
     }
-*/
 
-    //connect(d->socket, SIGNAL(newConnection()), this, SLOT(acceptNewConnection()));
+    connect(d->socket, SIGNAL(newConnection()), this, SLOT(acceptNewConnection()));
 }
 
 ListenSocket::~ListenSocket()
 {
     delete d;
 }
 
-void ListenSocket::acceptNewConnection(int handle)
+void ListenSocket::acceptNewConnection()
 {
     LOG_AS("ListenSocket::acceptNewConnection");
 
-    d->incoming.append(handle);
+    d->incoming.append(d->socket->nextPendingConnection());
 
     emit incomingConnection();
 }
@@ -102,9 +106,12 @@ Socket* ListenSocket::accept()
     {
         return 0;
     }
+    /*
     QTcpSocket* s = new QTcpSocket;
     s->setSocketDescriptor(d->incoming.takeFirst());
+    */
 
+    QTcpSocket* s = d->incoming.takeFirst();
     LOG_MSG("Accepted new connection from %s.") << s->peerAddress().toString();
 
     // We can use this constructor because we are Socket's friend.