First step of sending side of transport layer

Makefile

@@ -1,11 +1,11 @@
-source = parse.cpp parserstate.cpp parser.cpp templates.cpp terminal.cpp termemu.cpp parseraction.cpp terminalfunctions.cpp swrite.cpp terminalframebuffer.cpp terminaldispatcher.cpp terminaluserinput.cpp terminaldisplay.cpp network.cpp ntester.cpp ocb.cpp base64.cpp encrypt.cpp decrypt.cpp crypto.cpp
+source = parse.cpp parserstate.cpp parser.cpp templates.cpp terminal.cpp termemu.cpp parseraction.cpp terminalfunctions.cpp swrite.cpp terminalframebuffer.cpp terminaldispatcher.cpp terminaluserinput.cpp terminaldisplay.cpp network.cpp ntester.cpp ocb.cpp base64.cpp encrypt.cpp decrypt.cpp crypto.cpp networktransport.cpp
-objects = parserstate.o parser.o templates.o terminal.o parseraction.o terminalfunctions.o swrite.o terminalframebuffer.o terminaldispatcher.o terminaluserinput.o terminaldisplay.o network.o ocb.o base64.o crypto.o
+objects = parserstate.o parser.o templates.o terminal.o parseraction.o terminalfunctions.o swrite.o terminalframebuffer.o terminaldispatcher.o terminaluserinput.o terminaldisplay.o network.o ocb.o base64.o crypto.o networktransport.o
 repos = templates.rpo
 executables = parse termemu ntester encrypt decrypt
 
 CXX = g++
 CXXFLAGS = -g --std=c++0x -pedantic -Werror -Wall -Wextra -Weffc++ -fno-implicit-templates -fno-default-inline -pipe -D_FILE_OFFSET_BITS=64 -D_XOPEN_SOURCE=500 -D_GNU_SOURCE
-LIBS = -lutil -lssl
+LIBS = -lutil -lssl -lrt
 
 all: $(executables)
 

keystroke.hpp

@@ -4,27 +4,15 @@
 #include <string>
 #include <assert.h>
 
+using namespace std;
+
 class KeyStroke
 {
 public:
-  char letter;
+  void subtract( KeyStroke * const ) {}
-
+  string diff_from( KeyStroke const &, int ) { return ""; }
-  string tostring( void )
+  void apply_string( string ) {}
-  {
+  bool operator==( KeyStroke const & ) const { return true; }
-    return string( &letter, 1 );
-  };
-
-  KeyStroke( const string x )
-    : letter()
-  {
-    assert( x.size() == 1 );
-
-    letter = x[ 0 ];
-  }
-
-  KeyStroke()
-    : letter( 0 )
-  {}
 };
 
 #endif

networktransport.cpp

@@ -0,0 +1,177 @@
+#include <assert.h>
+
+#include "networktransport.hpp"
+
+using namespace Network;
+using namespace std;
+
+template <class MyState, class RemoteState>
+uint64_t Transport<MyState, RemoteState>::timestamp( void )
+{
+  struct timespec tp;
+
+  if ( clock_gettime( CLOCK_MONOTONIC, &tp ) < 0 ) {
+    throw NetworkException( "clock_gettime", errno );
+  }
+
+  uint64_t millis = tp.tv_nsec / 1000000;
+  millis += uint64_t( tp.tv_sec ) * 1000000;
+
+  return millis;
+}
+
+template <class MyState, class RemoteState>
+Transport<MyState, RemoteState>::Transport( MyState &initial_state )
+  : connection(),
+    server( true ),
+    current_state( initial_state ),
+    sent_states( 1, TimestampedState<MyState>( timestamp(), 0, initial_state ) ),
+    assumed_receiver_state( sent_states.begin() ),
+    timeout( INITIAL_TIMEOUT ),
+    highest_state_received( 0 )
+{
+  /* server */
+}
+
+template <class MyState, class RemoteState>
+Transport<MyState, RemoteState>::Transport( MyState &initial_state,
+					    const char *key_str, const char *ip, int port )
+  : connection( key_str, ip, port ),
+    server( false ),
+    current_state( initial_state ),
+    sent_states( 1, TimestampedState<MyState>( timestamp(), 0, initial_state ) ),
+    assumed_receiver_state( sent_states.begin() ),
+    timeout( INITIAL_TIMEOUT ),
+    highest_state_received( 0 )
+{
+  /* client */
+}
+
+template <class MyState, class RemoteState>
+void Transport<MyState, RemoteState>::new_state( MyState &s )
+{
+  current_state = s;
+
+  tick();
+}
+
+template <class MyState, class RemoteState>
+void Transport<MyState, RemoteState>::tick( void )
+{
+  /* Update assumed receiver state */
+  update_assumed_receiver_state();
+
+  /* Cut out common prefix of all states */
+  rationalize_states();
+
+  /* Determine if a new diff or empty ack needs to be sent */
+  if ( timestamp() - sent_states.back().timestamp >= int64_t( SEND_INTERVAL ) ) {
+    /* Send diffs or ack */
+    send_to_receiver();
+  }
+}
+
+template <class MyState, class RemoteState>
+void Transport<MyState, RemoteState>::send_to_receiver( void )
+{
+  if ( assumed_receiver_state->state == sent_states.back().state ) {
+    /* send empty ack */
+    Instruction inst( assumed_receiver_state->num,
+		      assumed_receiver_state->num,
+		      "",
+		      highest_state_received );
+    string s = inst.tostring();
+    connection.send( s );
+    sent_states.back().timestamp = timestamp();
+    return;
+  }
+
+  /* Otherwise, send sequence of diffs between assumed receiver state and current state */
+
+  /* We don't want to assume that this sequence of diffs will
+     necessarily bring the receiver to the _actual_ current
+     state. That requires perfect round-trip stability of the diff
+     mechanism -- stronger than we need (and probably too fragile).
+     Instead, we produce the full diff, unlimited by MTU, between
+     the assumed receiver state and current state, and apply that
+     diff to produce a target receiver state. Then we produce a
+     sequence of diffs (this time limited by MTU) that bring us to
+     that state. */
+
+  MyState target_receiver_state( assumed_receiver_state->state );
+  target_receiver_state.apply_string( current_state.diff_from( target_receiver_state, -1 ) );
+
+  while ( !(assumed_receiver_state->state == target_receiver_state) ) {
+    Instruction inst( assumed_receiver_state->num, -1,
+		      current_state.diff_from( assumed_receiver_state->state,
+					       connection.get_MTU() - HEADER_LEN ),
+		      highest_state_received );
+    MyState new_state = assumed_receiver_state->state;
+    new_state.apply_string( inst.diff );
+
+    /* Find the right "new_num" for this instruction. */
+    /* Has this state previously been sent? */
+    /* should replace with hash table if this becomes demanding */
+    typename list< TimestampedState<MyState> >::iterator previously_sent = sent_states.begin();
+    while ( ( previously_sent != sent_states.end() )
+	    && ( !(previously_sent->state == new_state) ) ) {
+      previously_sent++;
+    }
+
+    if ( previously_sent == sent_states.end() ) { /* not previously sent */
+      inst.new_num = sent_states.back().num + 1;
+      sent_states.push_back( TimestampedState<MyState>( timestamp(), inst.new_num, new_state ) );
+      previously_sent = sent_states.end();
+      previously_sent--;
+    } else {
+      inst.new_num = previously_sent->num;
+      previously_sent->timestamp = timestamp();
+    }
+
+    /* send instruction */
+    /* XXX what about MTU problem? */
+    string s = inst.tostring();
+
+    try {
+      connection.send( s );
+    } catch ( MTUException m ) {
+      continue;
+    }
+
+    /* successfully sent, probably */
+    /* ("probably" because the FIRST size-exceeded datagram doesn't get an error) */
+    assumed_receiver_state = previously_sent;
+  }
+}
+
+template <class MyState, class RemoteState>
+void Transport<MyState, RemoteState>::update_assumed_receiver_state( void )
+{
+  uint64_t now = timestamp();
+
+  /* start from what is known and give benefit of the doubt to unacknowledged states
+     transmitted recently enough ago */
+  assumed_receiver_state = sent_states.begin();
+
+  for ( typename list< TimestampedState<MyState> >::iterator i = sent_states.begin();
+	i != sent_states.end();
+	i++ ) {
+    assert( now >= i->timestamp );
+
+    if ( now - i->timestamp < int64_t(timeout) ) {
+      assumed_receiver_state = i;
+    }
+  }
+}
+
+template <class MyState, class RemoteState>
+void Transport<MyState, RemoteState>::rationalize_states( void )
+{
+  MyState * const known_receiver_state = &sent_states.front().state;
+
+  for ( typename list< TimestampedState<MyState> >::iterator i = sent_states.begin();
+	i != sent_states.end();
+	i++ ) {
+    i->state.subtract( known_receiver_state );
+  }
+}

networktransport.hpp

@@ -1,32 +1,84 @@
 #ifndef NETWORK_TRANSPORT_HPP
 #define NETWORK_TRANSPORT_HPP
 
-#include <google/dense_hash_map>
+#include <string>
+#include <signal.h>
+#include <time.h>
+#include <list>
 
-using google::dense_hash_map;
+#include "network.hpp"
+
+using namespace std;
 
 namespace Network {
+  class Instruction
+  {
+  public:
+    uint64_t old_num, new_num;
+    string diff;
+
+    uint64_t ack_num;
+
+    Instruction( uint64_t s_old_num, uint64_t s_new_num, string s_diff, uint64_t s_ack_num )
+      : old_num( s_old_num ), new_num( s_new_num ), diff( s_diff ), ack_num( s_ack_num )
+    {}
+
+    string tostring( void ) { return ""; }
+  };
+
+  template <class State>
+  class TimestampedState
+  {
+  public:
+    uint64_t timestamp;
+    uint64_t num;
+    State state;
+
+    TimestampedState( uint64_t s_timestamp, uint64_t s_num, State &s_state )
+      : timestamp( s_timestamp ), num( s_num ), state( s_state )
+    {}
+  };
+
   template <class MyState, class RemoteState>
   class Transport
   {
   private:
+    static const int INITIAL_TIMEOUT = 1000; /* ms, same as TCP */
+    static const int SEND_INTERVAL = 20; /* ms between frames */
+    static const int HEADER_LEN = 40;
+
+    /* helper methods for tick() */
+    void update_assumed_receiver_state( void );
+    void rationalize_states( void );
+    void send_to_receiver( void );
+
     Connection connection;
+    bool server;
 
-    typedef dense_hash_map< uint64_t, MyState > StateMapper;
+    uint64_t timestamp( void );
 
-    dense_hash_map< uint64_t, MyState > sent;
+    /* sender */
-    dense_hash_map< uint64_t, RemoteState > received;
+    MyState current_state;
 
-    uint64_t known_receiver_state;
+    list< TimestampedState<MyState> > sent_states;
-    uint64_t assumed_receiver_state;
+    /* first element: known, acknowledged receiver state */
-    uint64_t last_sent_state;
+    /* last element: last sent state */
+    /* somewhere in the middle: the assumed state of the receiver */
+
+    typename list< TimestampedState<MyState> >::iterator assumed_receiver_state;
+
+    int timeout;
+
+    /* simple receiver */
+    uint64_t highest_state_received;
 
   public:
-    Transport();
+    Transport( MyState &initial_state );
-    Transport( const char *key_str, const char *ip, int port );
+    Transport( MyState &initial_state, const char *key_str, const char *ip, int port );
 
-    
+    void new_state( MyState &s );
+    void tick( void );
   };
-};
+}
 
 #endif

templates.cpp

@@ -6,6 +6,9 @@
 
 #include "terminal.hpp"
 
+#include "keystroke.hpp"
+#include "networktransport.cpp"
+
 namespace Parser {
   class Action;
 }
@@ -22,3 +25,4 @@ template class vector<int>;
 template class map<string, Function>;
 template class vector<bool>;
 
+template class Network::Transport<KeyStroke, KeyStroke>;

terminal.hpp

@@ -24,6 +24,7 @@ namespace Terminal {
     friend void Parser::OSC_Start::act_on_terminal( Emulator * );
     friend void Parser::OSC_Put::act_on_terminal( Emulator * );
     friend void Parser::OSC_End::act_on_terminal( Emulator * );
+
     friend void Parser::UserByte::act_on_terminal( Emulator * );
     friend void Parser::Resize::act_on_terminal( Emulator * );