Improved J661 support: Difference between revisions

    diff --git a/src/Network/props.cxx b/src/Network/props.cxx

    index 7240d5c..bd014db 100644

    --- a/src/Network/props.cxx

    +++ b/src/Network/props.cxx

    @@ -33,6 +33,7 @@

    #include <simgear/misc/strutils.hxx>

    #include <simgear/props/props.hxx>

    #include <simgear/props/props_io.hxx>

    +#include <simgear/structure/exception.hxx>

    #include <sstream>

    #include <iostream>

    @@ -45,6 +46,12 @@

    #include "props.hxx"

    +#include <map>

    +#include <vector>

    +#include <string>

    +

    +#include <boost/functional/hash.hpp> // for property hashing (should probably be replaced eventually)

    +

    using std::stringstream;

    using std::ends;

    @@ -55,7 +62,7 @@ using std::endl;

      * Props connection class.

      * This class represents a connection to props client.

      */

    -class PropsChannel : public simgear::NetChat

    +class PropsChannel : public simgear::NetChat, public SGPropertyChangeListener

    {

        simgear::NetBuffer buffer;

    @@ -75,6 +82,7 @@ public:

          * Constructor.

          */

        PropsChannel();

    +    ~PropsChannel();

        /**

          * Append incoming data to our request buffer.

    @@ -89,10 +97,38 @@ public:

          */

        void foundTerminator();

    +    // callback for registered listeners (subscriptions)

    +    void valueChanged(SGPropertyNode *node);

    private:

    +

    +    typedef std::vector<std::string> ParameterList;

    +

    +

        inline void node_not_found_error( const string& s ) const {

            throw "node '" + s + "' not found";

        }

    +

    +    void error(std::string msg) {  // wrapper: prints errors to STDERR and to the telnet client

    +      push( msg.c_str() ); push( getTerminator() );

    +      SG_LOG(SG_GENERAL, SG_ALERT, __FILE__<<"@" << __LINE__ <<" in " << __FUNCTION__ <<":"<< msg.c_str() << std::endl);

    +    }

    +

    +

    +    bool check_args(ParameterList tok, unsigned int num, const char* func) {

    +      if (tok.size()-1 < num) {

    +          error(string("Wrong argument count for:")+string(func) );

    +          return false;

    +      }

    +      return true;

    +    }

    +

    +    std::vector<SGPropertyNode_ptr> _listeners;

    +    typedef void (PropsChannel::*TelnetCallback) (const ParameterList&);

    +    std::map<std::string, TelnetCallback> callback_map;

    +

    +    // callback implementations:

    +    void subscribe(const ParameterList &p);

    +    void unsubscribe(const ParameterList &p);

    };

    /**

    @@ -104,6 +140,67 @@ PropsChannel::PropsChannel()

          mode(PROMPT)

    {

        setTerminator( "\r\n" );

    +    callback_map["subscribe"]    =    &PropsChannel::subscribe;

    +    callback_map["unsubscribe"]  =  &PropsChannel::unsubscribe;

    +}

    +

    +PropsChannel::~PropsChannel() {

    +  // clean up all registered listeners   

    +  for (unsigned int i=0;i< _listeners.size(); i++)

    +    _listeners[i]->removeChangeListener( this  );

    +

    +}

    +

    +void PropsChannel::subscribe(const ParameterList& param) {

    +  if (! check_args(param,1,"subscribe")) return;

    +

    +  std::string command = param[0];

    +  const char* p = param[1].c_str();

    +  if (!p) return;

    +

    +        SG_LOG(SG_GENERAL, SG_ALERT, p << std::endl);

    +        push( command.c_str() ); push ( " " );

    +        push( p );

    +        push( getTerminator() );

    +

    +        SGPropertyNode *n = globals->get_props()->getNode( p,true );

    +  if ( n->isTied() ) {

    +      error("Error:Tied properties cannot register listeners");

    +      return;

    +  }

    +    if (n) {

    +        n->addChangeListener( this );

    +    std::stringstream hashcode;

    +    boost::hash<std::string> string_hash;

    +    hashcode << "id:" << string_hash(n->getPath()) << getTerminator();

    +    // push( hashcode.str().c_str() );  // not yet very useful

    +    _listeners.push_back( n ); // housekeeping, save for deletion in dtor later on

    +        }

    +        else {

    +      error("listener could not be added");

    +        }

    +

    +

    +}

    +

    +void PropsChannel::unsubscribe(const ParameterList &param) {

    +  if (!check_args(param,1,"unsubscribe")) return;

    +

    +  try {

    +  SGPropertyNode *n = globals->get_props()->getNode( param[1].c_str() );

    +  n->removeChangeListener( this );

    +  } catch (sg_exception &e) {

    +    error("Error:Listener could not be removed");

    +  }

    +}

    +

    +

    +//TODO: provide support for different types of subscriptions MODES ? (child added/removed, thesholds, min/max)

    +void PropsChannel::valueChanged(SGPropertyNode* ptr) {

    +  SG_LOG(SG_GENERAL, SG_ALERT, __FILE__<< "@"<<__LINE__ << ":" << __FUNCTION__ << std::endl);  

    +  std::stringstream response;

    +  response << ptr->getPath(true) << "=" <<  ptr->getStringValue() << "\r\n"; //TODO: use hashes, echo several properties at once, use proper terminator

    +  push( response.str().c_str() );

    }

    /**

    @@ -160,7 +257,7 @@ PropsChannel::foundTerminator()

        const char* cmd = buffer.getData();

        SG_LOG( SG_IO, SG_INFO, "processing command = \"" << cmd << "\"" );

    -    vector<string> tokens = simgear::strutils::split( cmd );

    +    ParameterList tokens = simgear::strutils::split( cmd );

        SGPropertyNode* node = globals->get_props()->getNode( path.c_str() );

    @@ -292,7 +389,7 @@ PropsChannel::foundTerminator()

                        if ( !globals->get_commands()

                                  ->execute( "reinit", &args) )

                        {

    -                        SG_LOG( SG_NETWORK, SG_ALERT,

    +                        SG_LOG( SG_GENERAL, SG_ALERT,

                                    "Command " << tokens[1] << " failed.");

                            if ( mode == PROMPT ) {

                                tmp += "*failed*";

    @@ -357,7 +454,7 @@ PropsChannel::foundTerminator()

                        if ( !globals->get_commands()

                                  ->execute(tokens[1].c_str(), &args) )

                        {

    -                        SG_LOG( SG_NETWORK, SG_ALERT,

    +                        SG_LOG( SG_GENERAL, SG_ALERT,

                                    "Command " << tokens[1] << " failed.");

                            if ( mode == PROMPT ) {

                                tmp += "*failed*";

    @@ -386,7 +483,14 @@ PropsChannel::foundTerminator()

                    mode = DATA;

                } else if ( command == "prompt" ) {

                    mode = PROMPT;

    -            } else {

    +            } else if (command  == "subscribe" || command == "unsubscribe") {

    +        TelnetCallback t = callback_map[ command.c_str() ]; //FIXME: use map lookup for condition

    +        if (t)

    +                (this->*t) (tokens);

    +        else

    +            error("No matching callback found for command:"+command);

    +      }

    +      else {

                    const char* msg = "\

    Valid commands are:\r\n\

    \r\n\

    @@ -400,7 +504,9 @@ prompt            switch to interactive mode (default)\r\n\

    pwd                display your current path\r\n\

    quit              terminate connection\r\n\

    run <command>      run built in command\r\n\

    -set <var> <val>    set <var> to a new <val>\r\n";

    +set <var> <val>    set <var> to a new <val>\r\n\

    +subscribe <var>      subscribe to property changes (returns hash code for property)\r\n\

    +unscubscribe <id>  unscubscribe from property changes (id must be the property hash as returned from subscribe command)\r\n";

                    push( msg );

                }

            }

    diff --git a/src/Network/props.hxx b/src/Network/props.hxx

    index e55f7c1..09b5a09 100644

    --- a/src/Network/props.hxx

    +++ b/src/Network/props.hxx

    @@ -40,7 +40,8 @@

      * FlightGear properties.

      */

    class FGProps : public FGProtocol,

    -      public simgear::NetChannel

    +      public simgear::NetChannel,

    +      public SGPropertyChangeListener // for subscriptions

    {

    private: