X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FScripting%2FNasalSys.cxx;h=502a406b2e6f88fed49e6bf310c7c7d2b459212f;hb=b5c46a8d59120f18b0bc268af72ecb6d3a75b3e3;hp=7ae4244647223dc679060b61f034747f5cff2ba6;hpb=52306b9093ee2c9d8483d02805dfa5fcf40fb526;p=flightgear.git

diff --git a/src/Scripting/NasalSys.cxx b/src/Scripting/NasalSys.cxx
index 7ae424464..502a406b2 100644
--- a/src/Scripting/NasalSys.cxx
+++ b/src/Scripting/NasalSys.cxx
@@ -3,10 +3,16 @@
 #  include "config.h"
 #endif
 
+#ifdef HAVE_SYS_TIME_H
+#  include <sys/time.h>  // gettimeofday
+#endif
+
 #include <string.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <fstream>
+#include <sstream>
 
 #include <plib/ul.h>
 
@@ -15,13 +21,23 @@
 #include <simgear/math/sg_random.h>
 #include <simgear/misc/sg_path.hxx>
 #include <simgear/misc/interpolator.hxx>
+#include <simgear/scene/material/mat.hxx>
 #include <simgear/structure/commands.hxx>
+#include <simgear/math/sg_geodesy.hxx>
+#include <simgear/structure/event_mgr.hxx>
 
+#include <Airports/runways.hxx>
+#include <Airports/simple.hxx>
 #include <Main/globals.hxx>
 #include <Main/fg_props.hxx>
+#include <Main/util.hxx>
+#include <Scenery/scenery.hxx>
 
 #include "NasalSys.hxx"
 
+static FGNasalSys* nasalSys = 0;
+
+
 // Read and return file contents in a single buffer.  Note use of
 // stat() to get the file size.  This is a win32 function, believe it
 // or not. :) Note the REALLY IMPORTANT use of the "b" flag to fopen.
@@ -52,20 +68,42 @@ static char* readfile(const char* file, int* lenOut)
 
 FGNasalSys::FGNasalSys()
 {
+    nasalSys = this;
     _context = 0;
     _globals = naNil();
     _gcHash = naNil();
     _nextGCKey = 0; // Any value will do
+    _callCount = 0;
+}
+
+// Does a naCall() in a new context.  Wrapped here to make lock
+// tracking easier.  Extension functions are called with the lock, but
+// we have to release it before making a new naCall().  So rather than
+// drop the lock in every extension function that might call back into
+// Nasal, we keep a stack depth counter here and only unlock/lock
+// around the naCall if it isn't the first one.
+naRef FGNasalSys::call(naRef code, int argc, naRef* args, naRef locals)
+{
+    naContext ctx = naNewContext();
+    if(_callCount) naModUnlock();
+    _callCount++;
+    naRef result = naCall(ctx, code, argc, args, naNil(), locals);
+    if(naGetError(ctx))
+        logError(ctx);
+    _callCount--;
+    if(_callCount) naModLock();
+    naFreeContext(ctx);
+    return result;
 }
 
 FGNasalSys::~FGNasalSys()
 {
-    // Nasal doesn't have a "destroy context" API yet. :(
-    // Not a problem for a global subsystem that will never be
-    // destroyed.  And the context is actually a global, so no memory
-    // is technically leaked (although the GC pool memory obviously
-    // won't be freed).
-    _context = 0;
+    nasalSys = 0;
+    map<int, FGNasalListener *>::iterator it, end = _listener.end();
+    for(it = _listener.begin(); it != end; ++it)
+        delete it->second;
+
+    naFreeContext(_context);
     _globals = naNil();
 }
 
@@ -75,12 +113,8 @@ bool FGNasalSys::parseAndRun(const char* sourceCode)
                        strlen(sourceCode));
     if(naIsNil(code))
         return false;
-
-    naCall(_context, code, 0, 0, naNil(), naNil());
-
-    if(!naGetError(_context)) return true;
-    logError(_context);
-    return false;
+    call(code, 0, 0, naNil());
+    return true;
 }
 
 FGNasalScript* FGNasalSys::parseScript(const char* src, const char* name)
@@ -91,7 +125,7 @@ FGNasalScript* FGNasalSys::parseScript(const char* src, const char* name)
 
     char buf[256];
     if(!name) {
-        sprintf(buf, "FGNasalScript@%p", script);
+        sprintf(buf, "FGNasalScript@%p", (void *)script);
         name = buf;
     }
 
@@ -124,11 +158,16 @@ void FGNasalSys::hashset(naRef hash, const char* key, naRef val)
 static SGPropertyNode* findnode(naContext c, naRef* vec, int len)
 {
     SGPropertyNode* p = globals->get_props();
-    for(int i=0; i<len; i++) {
-        naRef a = vec[i];
-        if(!naIsString(a)) return 0;
-        p = p->getNode(naStr_data(a));
-        if(p == 0) return 0;
+    try {
+        for(int i=0; i<len; i++) {
+            naRef a = vec[i];
+            if(!naIsString(a)) return 0;
+            p = p->getNode(naStr_data(a));
+            if(p == 0) return 0;
+        }
+    } catch (const string& err) {
+        naRuntimeError(c, (char *)err.c_str());
+        return 0;
     }
     return p;
 }
@@ -138,24 +177,25 @@ static SGPropertyNode* findnode(naContext c, naRef* vec, int len)
 // nil if it doesn't exist.
 static naRef f_getprop(naContext c, naRef me, int argc, naRef* args)
 {
+    using namespace simgear;
     const SGPropertyNode* p = findnode(c, args, argc);
     if(!p) return naNil();
 
     switch(p->getType()) {
-    case SGPropertyNode::BOOL:   case SGPropertyNode::INT:
-    case SGPropertyNode::LONG:   case SGPropertyNode::FLOAT:
-    case SGPropertyNode::DOUBLE:
+    case props::BOOL:   case props::INT:
+    case props::LONG:   case props::FLOAT:
+    case props::DOUBLE:
         return naNum(p->getDoubleValue());
 
-    case SGPropertyNode::STRING:
-    case SGPropertyNode::UNSPECIFIED:
+    case props::STRING:
+    case props::UNSPECIFIED:
         {
             naRef nastr = naNewString(c);
             const char* val = p->getStringValue();
             naStr_fromdata(nastr, (char*)val, strlen(val));
             return nastr;
         }
-    case SGPropertyNode::ALIAS: // <--- FIXME, recurse?
+    case props::ALIAS: // <--- FIXME, recurse?
     default:
         return naNil();
     }
@@ -185,9 +225,19 @@ static naRef f_setprop(naContext c, naRef me, int argc, naRef* args)
 
     SGPropertyNode* props = globals->get_props();
     naRef val = args[argc-1];
-    if(naIsString(val)) props->setStringValue(buf, naStr_data(val));
-    else                props->setDoubleValue(buf, naNumValue(val).num);
-    return naNil();
+    bool result = false;
+    try {
+        if(naIsString(val)) result = props->setStringValue(buf, naStr_data(val));
+        else {
+            naRef n = naNumValue(val);
+            if(naIsNil(n))
+                naRuntimeError(c, "setprop() value is not string or number");
+            result = props->setDoubleValue(buf, n.num);
+        }
+    } catch (const string& err) {
+        naRuntimeError(c, (char *)err.c_str());
+    }
+    return naNum(result);
 #undef BUFLEN
 }
 
@@ -196,24 +246,15 @@ static naRef f_setprop(naContext c, naRef me, int argc, naRef* args)
 // make sure it appears.  Is there better way to do this?
 static naRef f_print(naContext c, naRef me, int argc, naRef* args)
 {
-#define BUFLEN 1024
-    char buf[BUFLEN + 1];
-    buf[BUFLEN] = 0; // extra nul to handle strncpy brain damage
-    buf[0] = 0; // Zero-length in case there are no arguments
-    char* p = buf;
-    int buflen = BUFLEN;
+    string buf;
     int n = argc;
     for(int i=0; i<n; i++) {
         naRef s = naStringValue(c, args[i]);
         if(naIsNil(s)) continue;
-        strncpy(p, naStr_data(s), buflen);
-        p += naStr_len(s);
-        buflen = BUFLEN - (p - buf);
-        if(buflen <= 0) break;
+        buf += naStr_data(s);
     }
     SG_LOG(SG_GENERAL, SG_ALERT, buf);
-    return naNil();
-#undef BUFLEN
+    return naNum(buf.length());
 }
 
 // fgcommand() extension function.  Executes a named command via the
@@ -221,21 +262,25 @@ static naRef f_print(naContext c, naRef me, int argc, naRef* args)
 // an argument.
 static naRef f_fgcommand(naContext c, naRef me, int argc, naRef* args)
 {
-    if(argc < 2 || !naIsString(args[0]) || !naIsGhost(args[1]))
+    naRef cmd = argc > 0 ? args[0] : naNil();
+    naRef props = argc > 1 ? args[1] : naNil();
+    if(!naIsString(cmd) || (!naIsNil(props) && !naIsGhost(props)))
         naRuntimeError(c, "bad arguments to fgcommand()");
-    naRef cmd = args[0], props = args[1];
-    SGPropertyNode_ptr* node = (SGPropertyNode_ptr*)naGhost_ptr(props);
-    globals->get_commands()->execute(naStr_data(cmd), *node);
-    return naNil();
-
+    SGPropertyNode_ptr tmp, *node;
+    if(!naIsNil(props))
+        node = (SGPropertyNode_ptr*)naGhost_ptr(props);
+    else {
+        tmp = new SGPropertyNode();
+        node = &tmp;
+    }
+    return naNum(globals->get_commands()->execute(naStr_data(cmd), *node));
 }
 
 // settimer(func, dt, simtime) extension function.  Falls through to
 // FGNasalSys::setTimer().  See there for docs.
 static naRef f_settimer(naContext c, naRef me, int argc, naRef* args)
 {
-    FGNasalSys* nasal = (FGNasalSys*)globals->get_subsystem("nasal");
-    nasal->setTimer(argc, args);
+    nasalSys->setTimer(c, argc, args);
     return naNil();
 }
 
@@ -243,24 +288,21 @@ static naRef f_settimer(naContext c, naRef me, int argc, naRef* args)
 // FGNasalSys::setListener().  See there for docs.
 static naRef f_setlistener(naContext c, naRef me, int argc, naRef* args)
 {
-    FGNasalSys* nasal = (FGNasalSys*)globals->get_subsystem("nasal");
-    return nasal->setListener(argc, args);
+    return nasalSys->setListener(c, argc, args);
 }
 
 // removelistener(int) extension function. Falls through to
 // FGNasalSys::removeListener(). See there for docs.
 static naRef f_removelistener(naContext c, naRef me, int argc, naRef* args)
 {
-    FGNasalSys* nasal = (FGNasalSys*)globals->get_subsystem("nasal");
-    return nasal->removeListener(argc, args);
+    return nasalSys->removeListener(c, argc, args);
 }
 
 // Returns a ghost handle to the argument to the currently executing
 // command
 static naRef f_cmdarg(naContext c, naRef me, int argc, naRef* args)
 {
-    FGNasalSys* nasal = (FGNasalSys*)globals->get_subsystem("nasal");
-    return nasal->cmdArgGhost();
+    return nasalSys->cmdArgGhost();
 }
 
 // Sets up a property interpolation.  The first argument is either a
@@ -285,9 +327,12 @@ static naRef f_interpolate(naContext c, naRef me, int argc, naRef* args)
         deltas[i] = naNumValue(naVec_get(curve, 2*i+1)).num;
     }
 
-    ((SGInterpolator*)globals->get_subsystem("interpolator"))
+    ((SGInterpolator*)globals->get_subsystem_mgr()
+        ->get_group(SGSubsystemMgr::INIT)->get_subsystem("interpolator"))
         ->interpolate(node, nPoints, values, deltas);
 
+    delete[] values;
+    delete[] deltas;
     return naNil();
 }
 
@@ -305,6 +350,12 @@ static naRef f_srand(naContext c, naRef me, int argc, naRef* args)
     return naNum(0);
 }
 
+static naRef f_abort(naContext c, naRef me, int argc, naRef* args)
+{
+    abort();
+    return naNil();
+}
+
 // Return an array listing of all files in a directory
 static naRef f_directory(naContext c, naRef me, int argc, naRef* args)
 {
@@ -322,8 +373,249 @@ static naRef f_directory(naContext c, naRef me, int argc, naRef* args)
     return result;
 }
 
+// Parse XML file.
+//     parsexml(<path> [, <start-tag> [, <end-tag> [, <data> [, <pi>]]]]);
+//
+// <path>      ... absolute path to an XML file
+// <start-tag> ... callback function with two args: tag name, attribute hash
+// <end-tag>   ... callback function with one arg:  tag name
+// <data>      ... callback function with one arg:  data
+// <pi>        ... callback function with two args: target, data
+//                 (pi = "processing instruction")
+// All four callback functions are optional and default to nil.
+// The function returns nil on error, or the validated file name otherwise.
+static naRef f_parsexml(naContext c, naRef me, int argc, naRef* args)
+{
+    if(argc < 1 || !naIsString(args[0]))
+        naRuntimeError(c, "parsexml(): path argument missing or not a string");
+    if(argc > 5) argc = 5;
+    for(int i=1; i<argc; i++)
+        if(!(naIsNil(args[i]) || naIsFunc(args[i])))
+            naRuntimeError(c, "parsexml(): callback argument not a function");
+
+    const char* file = fgValidatePath(naStr_data(args[0]), false);
+    if(!file) {
+        naRuntimeError(c, "parsexml(): reading '%s' denied "
+                "(unauthorized access)", naStr_data(args[0]));
+        return naNil();
+    }
+    std::ifstream input(file);
+    NasalXMLVisitor visitor(c, argc, args);
+    try {
+        readXML(input, visitor);
+    } catch (const sg_exception& e) {
+        naRuntimeError(c, "parsexml(): file '%s' %s",
+                file, e.getFormattedMessage().c_str());
+        return naNil();
+    }
+    return naStr_fromdata(naNewString(c), const_cast<char*>(file), strlen(file));
+}
+
+// Return UNIX epoch time in seconds.
+static naRef f_systime(naContext c, naRef me, int argc, naRef* args)
+{
+#ifdef WIN32
+    FILETIME ft;
+    GetSystemTimeAsFileTime(&ft);
+    double t = (4294967296.0 * ft.dwHighDateTime + ft.dwLowDateTime);
+    // Converts from 100ns units in 1601 epoch to unix epoch in sec
+    return naNum((t * 1e-7) - 11644473600.0);
+#else
+    time_t t;
+    struct timeval td;
+    do { t = time(0); gettimeofday(&td, 0); } while(t != time(0));
+    return naNum(t + 1e-6 * td.tv_usec);
+#endif
+}
+
+// Convert a cartesian point to a geodetic lat/lon/altitude.
+static naRef f_carttogeod(naContext c, naRef me, int argc, naRef* args)
+{
+    double lat, lon, alt, xyz[3];
+    if(argc != 3) naRuntimeError(c, "carttogeod() expects 3 arguments");
+    for(int i=0; i<3; i++)
+        xyz[i] = naNumValue(args[i]).num;
+    sgCartToGeod(xyz, &lat, &lon, &alt);
+    lat *= SG_RADIANS_TO_DEGREES;
+    lon *= SG_RADIANS_TO_DEGREES;
+    naRef vec = naNewVector(c);
+    naVec_append(vec, naNum(lat));
+    naVec_append(vec, naNum(lon));
+    naVec_append(vec, naNum(alt));
+    return vec;
+}
+
+// Convert a geodetic lat/lon/altitude to a cartesian point.
+static naRef f_geodtocart(naContext c, naRef me, int argc, naRef* args)
+{
+    if(argc != 3) naRuntimeError(c, "geodtocart() expects 3 arguments");
+    double lat = naNumValue(args[0]).num * SG_DEGREES_TO_RADIANS;
+    double lon = naNumValue(args[1]).num * SG_DEGREES_TO_RADIANS;
+    double alt = naNumValue(args[2]).num;
+    double xyz[3];
+    sgGeodToCart(lat, lon, alt, xyz);
+    naRef vec = naNewVector(c);
+    naVec_append(vec, naNum(xyz[0]));
+    naVec_append(vec, naNum(xyz[1]));
+    naVec_append(vec, naNum(xyz[2]));
+    return vec;
+}
+
+// For given geodetic point return array with elevation, and a material data
+// hash, or nil if there's no information available (tile not loaded). If
+// information about the material isn't available, then nil is returned instead
+// of the hash.
+static naRef f_geodinfo(naContext c, naRef me, int argc, naRef* args)
+{
+#define HASHSET(s,l,n) naHash_set(matdata, naStr_fromdata(naNewString(c),s,l),n)
+    if(argc < 2 || argc > 3)
+        naRuntimeError(c, "geodinfo() expects 2 or 3 arguments: lat, lon [, maxalt]");
+    double lat = naNumValue(args[0]).num;
+    double lon = naNumValue(args[1]).num;
+    double elev = argc == 3 ? naNumValue(args[2]).num : 10000;
+    const SGMaterial *mat;
+    SGGeod geod = SGGeod::fromDegM(lon, lat, elev);
+    if(!globals->get_scenery()->get_elevation_m(geod, elev, &mat))
+        return naNil();
+    naRef vec = naNewVector(c);
+    naVec_append(vec, naNum(elev));
+    naRef matdata = naNil();
+    if(mat) {
+        matdata = naNewHash(c);
+        naRef names = naNewVector(c);
+        const vector<string> n = mat->get_names();
+        for(unsigned int i=0; i<n.size(); i++)
+            naVec_append(names, naStr_fromdata(naNewString(c),
+                    const_cast<char*>(n[i].c_str()), n[i].size()));
+        HASHSET("names", 5, names);
+        HASHSET("solid", 5, naNum(mat->get_solid()));
+        HASHSET("friction_factor", 15, naNum(mat->get_friction_factor()));
+        HASHSET("rolling_friction", 16, naNum(mat->get_rolling_friction()));
+        HASHSET("load_resistance", 15, naNum(mat->get_load_resistance()));
+        HASHSET("bumpiness", 9, naNum(mat->get_bumpiness()));
+        HASHSET("light_coverage", 14, naNum(mat->get_light_coverage()));
+    }
+    naVec_append(vec, matdata);
+    return vec;
+#undef HASHSET
+}
+
+
+class AirportInfoFilter : public FGAirport::AirportFilter
+{
+public:
+    AirportInfoFilter() : type(FGPositioned::AIRPORT) {
+    }
+
+    virtual FGPositioned::Type minType() const {
+        return type;
+    }
+
+    virtual FGPositioned::Type maxType() const {
+        return type;
+    }
+
+    FGPositioned::Type type;
+};
+
+// Returns data hash for particular or nearest airport of a <type>, or nil
+// on error.
+//
+// airportinfo(<id>);                   e.g. "KSFO"
+// airportinfo(<type>);                 type := ("airport"|"seaport"|"heliport")
+// airportinfo()                        same as  airportinfo("airport")
+// airportinfo(<lat>, <lon> [, <type>]);
+static naRef f_airportinfo(naContext c, naRef me, int argc, naRef* args)
+{
+    static SGConstPropertyNode_ptr latn = fgGetNode("/position/latitude-deg", true);
+    static SGConstPropertyNode_ptr lonn = fgGetNode("/position/longitude-deg", true);
+    SGGeod pos;
+    FGAirport* apt = NULL;
+
+    if(argc >= 2 && naIsNum(args[0]) && naIsNum(args[1])) {
+        pos = SGGeod::fromDeg(args[1].num, args[0].num);
+        args += 2;
+        argc -= 2;
+    } else {
+        pos = SGGeod::fromDeg(lonn->getDoubleValue(), latn->getDoubleValue());
+    }
+
+    double maxRange = 10000.0; // expose this? or pick a smaller value?
+
+    AirportInfoFilter filter; // defaults to airports only
+
+    if(argc == 0) {
+        // fall through and use AIRPORT
+    } else if(argc == 1 && naIsString(args[0])) {
+        const char *s = naStr_data(args[0]);
+        if(!strcmp(s, "airport")) filter.type = FGPositioned::AIRPORT;
+        else if(!strcmp(s, "seaport")) filter.type = FGPositioned::SEAPORT;
+        else if(!strcmp(s, "heliport")) filter.type = FGPositioned::HELIPORT;
+        else {
+            // user provided an <id>, hopefully
+            apt = FGAirport::findByIdent(s);
+            if (!apt) {
+                // return nil here, but don't raise a runtime error; this is a
+                // legitamate way to validate an ICAO code, for example in a
+                // dialog box or similar.
+                return naNil();
+            }
+        }
+    } else {
+        naRuntimeError(c, "airportinfo() with invalid function arguments");
+        return naNil();
+    }
+
+    if(!apt) {
+        apt = FGAirport::findClosest(pos, maxRange, &filter);
+        if(!apt) return naNil();
+    }
+
+    string id = apt->ident();
+    string name = apt->name();
+
+    // set runway hash
+    naRef rwys = naNewHash(c);
+    for(unsigned int r=0; r<apt->numRunways(); ++r) {
+        FGRunway* rwy(apt->getRunwayByIndex(r));
+
+        naRef rwyid = naStr_fromdata(naNewString(c),
+                      const_cast<char *>(rwy->ident().c_str()),
+                      rwy->ident().length());
+
+        naRef rwydata = naNewHash(c);
+#define HASHSET(s,l,n) naHash_set(rwydata, naStr_fromdata(naNewString(c),s,l),n)
+        HASHSET("id", 2, rwyid);
+        HASHSET("lat", 3, naNum(rwy->latitude()));
+        HASHSET("lon", 3, naNum(rwy->longitude()));
+        HASHSET("heading", 7, naNum(rwy->headingDeg()));
+        HASHSET("length", 6, naNum(rwy->lengthM()));
+        HASHSET("width", 5, naNum(rwy->widthM()));
+        HASHSET("threshold", 9, naNum(rwy->displacedThresholdM()));
+        HASHSET("stopway", 7, naNum(rwy->stopwayM()));
+#undef HASHSET
+        naHash_set(rwys, rwyid, rwydata);
+    }
+
+    // set airport hash
+    naRef aptdata = naNewHash(c);
+#define HASHSET(s,l,n) naHash_set(aptdata, naStr_fromdata(naNewString(c),s,l),n)
+    HASHSET("id", 2, naStr_fromdata(naNewString(c),
+            const_cast<char *>(id.c_str()), id.length()));
+    HASHSET("name", 4, naStr_fromdata(naNewString(c),
+            const_cast<char *>(name.c_str()), name.length()));
+    HASHSET("lat", 3, naNum(apt->getLatitude()));
+    HASHSET("lon", 3, naNum(apt->getLongitude()));
+    HASHSET("elevation", 9, naNum(apt->getElevation() * SG_FEET_TO_METER));
+    HASHSET("has_metar", 9, naNum(apt->getMetar()));
+    HASHSET("runways", 7, rwys);
+#undef HASHSET
+    return aptdata;
+}
+
+
 // Table of extension functions.  Terminate with zeros.
-static struct { char* name; naCFunction func; } funcs[] = {
+static struct { const char* name; naCFunction func; } funcs[] = {
     { "getprop",   f_getprop },
     { "setprop",   f_setprop },
     { "print",     f_print },
@@ -335,7 +627,14 @@ static struct { char* name; naCFunction func; } funcs[] = {
     { "_interpolate",  f_interpolate },
     { "rand",  f_rand },
     { "srand",  f_srand },
+    { "abort", f_abort },
     { "directory", f_directory },
+    { "parsexml", f_parsexml },
+    { "systime", f_systime },
+    { "carttogeod", f_carttogeod },
+    { "geodtocart", f_geodtocart },
+    { "geodinfo", f_geodinfo },
+    { "airportinfo", f_airportinfo },
     { 0, 0 }
 };
 
@@ -354,17 +653,15 @@ void FGNasalSys::init()
     // sub-reference under the name "globals".  This gives client-code
     // write access to the namespace if someone wants to do something
     // fancy.
-    _globals = naStdLib(_context);
+    _globals = naInit_std(_context);
     naSave(_context, _globals);
     hashset(_globals, "globals", _globals);
 
-    // Add in the math library under "math"
-    hashset(_globals, "math", naMathLib(_context));
-
-    // Add in the IO library.  Disabled currently until after the
-    // 0.9.10 release.
-    // hashset(_globals, "io", naIOLib(_context));
-    // hashset(_globals, "bits", naBitsLib(_context));
+    hashset(_globals, "math", naInit_math(_context));
+    hashset(_globals, "bits", naInit_bits(_context));
+    hashset(_globals, "io", naInit_io(_context));
+    hashset(_globals, "thread", naInit_thread(_context));
+    hashset(_globals, "utf8", naInit_utf8(_context));
 
     // Add our custom extension functions:
     for(i=0; funcs[i].name; i++)
@@ -394,10 +691,38 @@ void FGNasalSys::init()
     }
     ulCloseDir(dir);
 
+    // set signal and remove node to avoid restoring at reinit
+    const char *s = "nasal-dir-initialized";
+    SGPropertyNode *signal = fgGetNode("/sim/signals", true);
+    signal->setBoolValue(s, true);
+    signal->removeChildren(s, false);
+
     // Pull scripts out of the property tree, too
     loadPropertyScripts();
 }
 
+void FGNasalSys::update(double)
+{
+    if(!_dead_listener.empty()) {
+        vector<FGNasalListener *>::iterator it, end = _dead_listener.end();
+        for(it = _dead_listener.begin(); it != end; ++it) delete *it;
+        _dead_listener.clear();
+    }
+
+    // The global context is a legacy thing.  We use dynamically
+    // created contexts for naCall() now, so that we can call them
+    // recursively.  But there are still spots that want to use it for
+    // naNew*() calls, which end up leaking memory because the context
+    // only clears out its temporary vector when it's *used*.  So just
+    // junk it and fetch a new/reinitialized one every frame.  This is
+    // clumsy: the right solution would use the dynamic context in all
+    // cases and eliminate _context entirely.  But that's more work,
+    // and this works fine (yes, they say "New" and "Free", but
+    // they're very fast, just trust me). -Andy
+    naFreeContext(_context);
+    _context = naNewContext();
+}
+
 // Loads the scripts found under /nasal in the global tree
 void FGNasalSys::loadPropertyScripts()
 {
@@ -411,12 +736,12 @@ void FGNasalSys::loadPropertyScripts()
         if(n->hasChild("module"))
             module = n->getStringValue("module");
 
-        // allow multiple files to be specified within in a single
+        // allow multiple files to be specified within a single
         // Nasal module tag
         int j = 0;
         SGPropertyNode *fn;
         bool file_specified = false;
-        while ( (fn = n->getChild("file", j)) != NULL ) {
+        while((fn = n->getChild("file", j)) != NULL) {
             file_specified = true;
             const char* file = fn->getStringValue();
             SGPath p(globals->get_fg_root());
@@ -425,17 +750,6 @@ void FGNasalSys::loadPropertyScripts()
             j++;
         }
 
-        // Old code which only allowed a single file to be specified per module
-        /*
-        const char* file = n->getStringValue("file");
-        if(!n->hasChild("file")) file = 0; // Hrm...
-        if(file) {
-            SGPath p(globals->get_fg_root());
-            p.append(file);
-            loadModule(p, module);
-        }
-        */
-        
         const char* src = n->getStringValue("script");
         if(!n->hasChild("script")) src = 0; // Hrm...
         if(src)
@@ -481,9 +795,13 @@ void FGNasalSys::loadModule(SGPath file, const char* module)
 }
 
 // Parse and run.  Save the local variables namespace, as it will
-// become a sub-object of globals.
+// become a sub-object of globals.  The optional "arg" argument can be
+// used to pass an associated property node to the module, which can then
+// be accessed via cmdarg().  (This is, for example, used by XML dialogs.)
 void FGNasalSys::createModule(const char* moduleName, const char* fileName,
-                              const char* src, int len, const SGPropertyNode* arg)
+                              const char* src, int len,
+                              const SGPropertyNode* cmdarg,
+                              int argc, naRef* args)
 {
     naRef code = parse(fileName, src, len);
     if(naIsNil(code))
@@ -498,13 +816,9 @@ void FGNasalSys::createModule(const char* moduleName, const char* fileName,
     if(!naHash_get(_globals, modname, &locals))
         locals = naNewHash(_context);
 
-    _cmdArg = (SGPropertyNode*)arg;
+    _cmdArg = (SGPropertyNode*)cmdarg;
 
-    naCall(_context, code, 0, 0, naNil(), locals);
-    if(naGetError(_context)) {
-        logError(_context);
-        return;
-    }
+    call(code, argc, args, locals);
     hashset(_globals, moduleName, locals);
 }
 
@@ -512,9 +826,7 @@ void FGNasalSys::deleteModule(const char* moduleName)
 {
     naRef modname = naNewString(_context);
     naStr_fromdata(modname, (char*)moduleName, strlen(moduleName));
-    naModLock();
     naHash_delete(_globals, modname);
-    naModUnlock();
 }
 
 naRef FGNasalSys::parse(const char* filename, const char* buf, int len)
@@ -541,29 +853,26 @@ bool FGNasalSys::handleCommand(const SGPropertyNode* arg)
     naRef code = parse(arg->getPath(true), nasal, strlen(nasal));
     if(naIsNil(code)) return false;
 
-    naContext c = naNewContext();
+    // Commands can be run "in" a module.  Make sure that module
+    // exists, and set it up as the local variables hash for the
+    // command.
     naRef locals = naNil();
     if(moduleName[0]) {
-        naRef modname = naNewString(c);
+        naRef modname = naNewString(_context);
         naStr_fromdata(modname, (char*)moduleName, strlen(moduleName));
-        if(!naHash_get(_globals, modname, &locals))
-            locals = naNewHash(c);
+        if(!naHash_get(_globals, modname, &locals)) {
+            locals = naNewHash(_context);
+            naHash_set(_globals, modname, locals);
+        }
     }
-    // Cache the command argument for inspection via cmdarg().  For
+
+    // Cache this command's argument for inspection via cmdarg().  For
     // performance reasons, we won't bother with it if the invoked
     // code doesn't need it.
     _cmdArg = (SGPropertyNode*)arg;
 
-    // Call it!
-    naModUnlock();
-    naRef result = naCall(c, code, 0, 0, naNil(), locals);
-    naModLock();
-    bool error = naGetError(c);
-    if(error)
-       logError(c);
-
-    naFreeContext(c);
-    return !error;
+    call(code, 0, 0, locals);
+    return true;
 }
 
 // settimer(func, dt, simtime) extension function.  The first argument
@@ -576,15 +885,20 @@ bool FGNasalSys::handleCommand(const SGPropertyNode* arg)
 // "saved" somehow lest they be inadvertently cleaned.  In this case,
 // they are inserted into a globals.__gcsave hash and removed on
 // expiration.
-void FGNasalSys::setTimer(int argc, naRef* args)
+void FGNasalSys::setTimer(naContext c, int argc, naRef* args)
 {
     // Extract the handler, delta, and simtime arguments:
     naRef handler = argc > 0 ? args[0] : naNil();
-    if(!(naIsCode(handler) || naIsCCode(handler) || naIsFunc(handler)))
+    if(!(naIsCode(handler) || naIsCCode(handler) || naIsFunc(handler))) {
+        naRuntimeError(c, "settimer() with invalid function argument");
         return;
+    }
 
     naRef delta = argc > 1 ? args[1] : naNil();
-    if(naIsNil(delta)) return;
+    if(naIsNil(delta)) {
+        naRuntimeError(c, "settimer() with invalid time argument");
+        return;
+    }
 
     bool simtime = (argc > 2 && naTrue(args[2])) ? false : true;
 
@@ -601,9 +915,7 @@ void FGNasalSys::setTimer(int argc, naRef* args)
 
 void FGNasalSys::handleTimer(NasalTimer* t)
 {
-    naCall(_context, t->handler, 0, 0, naNil(), naNil());
-    if(naGetError(_context))
-        logError(_context);
+    call(t->handler, 0, 0, naNil());
     gcRelease(t->gcKey);
 }
 
@@ -627,29 +939,43 @@ void FGNasalSys::NasalTimer::timerExpired()
 
 int FGNasalSys::_listenerId = 0;
 
-// setlistener(property, func, bool) extension function.  The first argument
-// is either a ghost (SGPropertyNode_ptr*) or a string (global property
-// path), the second is a Nasal function, the optional third one a bool.
-// If the bool is true, then the listener is executed initially. The
-// setlistener() function returns a unique id number, that can be used
-// as argument to the removelistener() function.
-naRef FGNasalSys::setListener(int argc, naRef* args)
+// setlistener(<property>, <func> [, <initial=0> [, <persistent=1>]])
+// Attaches a callback function to a property (specified as a global
+// property path string or a SGPropertyNode_ptr* ghost). If the third,
+// optional argument (default=0) is set to 1, then the function is also
+// called initially. If the fourth, optional argument is set to 0, then the
+// function is only called when the property node value actually changes.
+// Otherwise it's called independent of the value whenever the node is
+// written to (default). The setlistener() function returns a unique
+// id number, which is to be used as argument to the removelistener()
+// function.
+naRef FGNasalSys::setListener(naContext c, int argc, naRef* args)
 {
     SGPropertyNode_ptr node;
     naRef prop = argc > 0 ? args[0] : naNil();
     if(naIsString(prop)) node = fgGetNode(naStr_data(prop), true);
     else if(naIsGhost(prop)) node = *(SGPropertyNode_ptr*)naGhost_ptr(prop);
-    else return naNil();
+    else {
+        naRuntimeError(c, "setlistener() with invalid property argument");
+        return naNil();
+    }
 
-    naRef handler = argc > 1 ? args[1] : naNil();
-    if(!(naIsCode(handler) || naIsCCode(handler) || naIsFunc(handler)))
+    if(node->isTied())
+        SG_LOG(SG_NASAL, SG_DEBUG, "Attaching listener to tied property " <<
+                node->getPath());
+
+    naRef code = argc > 1 ? args[1] : naNil();
+    if(!(naIsCode(code) || naIsCCode(code) || naIsFunc(code))) {
+        naRuntimeError(c, "setlistener() with invalid function argument");
         return naNil();
+    }
 
-    bool initial = argc > 2 && naTrue(args[2]);
+    int init = argc > 2 && naIsNum(args[2]) ? int(args[2].num) : 0;
+    int type = argc > 3 && naIsNum(args[3]) ? int(args[3].num) : 1;
+    FGNasalListener *nl = new FGNasalListener(node, code, this,
+            gcSave(code), _listenerId, init, type);
 
-    FGNasalListener *nl = new FGNasalListener(node, handler, this,
-            gcSave(handler));
-    node->addChangeListener(nl, initial);
+    node->addChangeListener(nl, init);
 
     _listener[_listenerId] = nl;
     return naNum(_listenerId++);
@@ -657,20 +983,19 @@ naRef FGNasalSys::setListener(int argc, naRef* args)
 
 // removelistener(int) extension function. The argument is the id of
 // a listener as returned by the setlistener() function.
-naRef FGNasalSys::removeListener(int argc, naRef* args)
+naRef FGNasalSys::removeListener(naContext c, int argc, naRef* args)
 {
     naRef id = argc > 0 ? args[0] : naNil();
-    if(!naIsNum(id))
-        return naNil();
+    map<int, FGNasalListener *>::iterator it = _listener.find(int(id.num));
 
-    int i = int(id.num);
-    if (_listener.find(i) == _listener.end())
+    if(!naIsNum(id) || it == _listener.end() || it->second->_dead) {
+        naRuntimeError(c, "removelistener() with invalid listener id");
         return naNil();
+    }
 
-    FGNasalListener *nl = _listener[i];
-    nl->_node->removeChangeListener(nl);
-    _listener.erase(i);
-    delete nl;
+    it->second->_dead = true;
+    _dead_listener.push_back(it->second);
+    _listener.erase(it);
     return naNum(_listener.size());
 }
 
@@ -678,40 +1003,99 @@ naRef FGNasalSys::removeListener(int argc, naRef* args)
 
 // FGNasalListener class.
 
-FGNasalListener::FGNasalListener(SGPropertyNode_ptr node, naRef handler,
-                                 FGNasalSys* nasal, int key) :
+FGNasalListener::FGNasalListener(SGPropertyNode *node, naRef code,
+                                 FGNasalSys* nasal, int key, int id,
+                                 int init, int type) :
     _node(node),
-    _handler(handler),
+    _code(code),
     _gcKey(key),
+    _id(id),
     _nas(nasal),
-    _active(0)
+    _init(init),
+    _type(type),
+    _active(0),
+    _dead(false),
+    _last_int(0L),
+    _last_float(0.0)
 {
+    if(_type == 0 && !_init)
+        changed(node);
 }
 
 FGNasalListener::~FGNasalListener()
 {
+    _node->removeChangeListener(this);
     _nas->gcRelease(_gcKey);
 }
 
-void FGNasalListener::valueChanged(SGPropertyNode* node)
+void FGNasalListener::call(SGPropertyNode* which, naRef mode)
 {
-    if (_active) {
-        SG_LOG(SG_NASAL, SG_ALERT, "Recursive listener call "
-                "on property " << node->getPath());
-        return;
-    }
+    if(_active || _dead) return;
+    SG_LOG(SG_NASAL, SG_DEBUG, "trigger listener #" << _id);
     _active++;
-    _nas->_cmdArg = node;
-    naContext c = naNewContext();
-    naModUnlock();
-    naCall(c, _handler, 0, 0, naNil(), naNil());
-    naModLock();
-    if(naGetError(c))
-        _nas->logError(c);
-    naFreeContext(c);
+    naRef arg[4];
+    arg[0] = _nas->propNodeGhost(which);
+    arg[1] = _nas->propNodeGhost(_node);
+    arg[2] = mode;                  // value changed, child added/removed
+    arg[3] = naNum(_node != which); // child event?
+    _nas->call(_code, 4, arg, naNil());
     _active--;
 }
 
+void FGNasalListener::valueChanged(SGPropertyNode* node)
+{
+    if(_type < 2 && node != _node) return;   // skip child events
+    if(_type > 0 || changed(_node) || _init)
+        call(node, naNum(0));
+
+    _init = 0;
+}
+
+void FGNasalListener::childAdded(SGPropertyNode*, SGPropertyNode* child)
+{
+    if(_type == 2) call(child, naNum(1));
+}
+
+void FGNasalListener::childRemoved(SGPropertyNode*, SGPropertyNode* child)
+{
+    if(_type == 2) call(child, naNum(-1));
+}
+
+bool FGNasalListener::changed(SGPropertyNode* node)
+{
+    using namespace simgear;
+    props::Type type = node->getType();
+    if(type == props::NONE) return false;
+    if(type == props::UNSPECIFIED) return true;
+
+    bool result;
+    switch(type) {
+    case props::BOOL:
+    case props::INT:
+    case props::LONG:
+        {
+            long l = node->getLongValue();
+            result = l != _last_int;
+            _last_int = l;
+            return result;
+        }
+    case props::FLOAT:
+    case props::DOUBLE:
+        {
+            double d = node->getDoubleValue();
+            result = d != _last_float;
+            _last_float = d;
+            return result;
+        }
+    default:
+        {
+            string s = node->getStringValue();
+            result = s != _last_string;
+            _last_string = s;
+            return result;
+        }
+    }
+}
 
 
 
@@ -720,41 +1104,107 @@ void FGNasalListener::valueChanged(SGPropertyNode* node)
 // destructor the <unload> script. The latter happens when the model branch
 // is removed from the scene graph.
 
+unsigned int FGNasalModelData::_module_id = 0;
+
 void FGNasalModelData::modelLoaded(const string& path, SGPropertyNode *prop,
-                                   ssgBranch *)
+                                   osg::Node *)
 {
-    SGPropertyNode *n = prop->getNode("nasal"), *load;
-    if (!n)
+    if(!prop)
+        return;
+    SGPropertyNode *nasal = prop->getNode("nasal");
+    if(!nasal)
         return;
 
-    load = n->getNode("load");
-    _unload = n->getNode("unload");
-    if (!load && !_unload)
+    SGPropertyNode *load = nasal->getNode("load");
+    _unload = nasal->getNode("unload");
+    if(!load && !_unload)
         return;
 
-    _module = path;
+    std::stringstream m;
+    m << "__model" << _module_id++;
+    _module = m.str();
+
     const char *s = load ? load->getStringValue() : "";
-    FGNasalSys *nas = (FGNasalSys *)globals->get_subsystem("nasal");
-    nas->createModule(_module.c_str(), _module.c_str(), s, strlen(s));
+
+    naRef arg[2];
+    arg[0] = nasalSys->propNodeGhost(_root);
+    arg[1] = nasalSys->propNodeGhost(prop);
+    nasalSys->createModule(_module.c_str(), path.c_str(), s, strlen(s),
+                           _root, 2, arg);
 }
 
 FGNasalModelData::~FGNasalModelData()
 {
-    if (_module.empty())
+    if(_module.empty())
         return;
 
-    FGNasalSys *nas = (FGNasalSys *)globals->get_subsystem("nasal");
-    if (!nas) {
-        SG_LOG(SG_NASAL, SG_ALERT, "Trying to run an <unload> script "
+    if(!nasalSys) {
+        SG_LOG(SG_NASAL, SG_WARN, "Trying to run an <unload> script "
                 "without Nasal subsystem present.");
         return;
     }
 
-    if (_unload) {
+    if(_unload) {
         const char *s = _unload->getStringValue();
-        nas->createModule(_module.c_str(), _module.c_str(), s, strlen(s));
+        nasalSys->createModule(_module.c_str(), _module.c_str(), s, strlen(s), _root);
+    }
+    nasalSys->deleteModule(_module.c_str());
+}
+
+
+
+// NasalXMLVisitor class: handles EasyXML visitor callback for parsexml()
+//
+NasalXMLVisitor::NasalXMLVisitor(naContext c, int argc, naRef* args) :
+    _c(naSubContext(c)),
+    _start_element(argc > 1 ? args[1] : naNil()),
+    _end_element(argc > 2 ? args[2] : naNil()),
+    _data(argc > 3 ? args[3] : naNil()),
+    _pi(argc > 4 ? args[4] : naNil())
+{
+}
+
+void NasalXMLVisitor::startElement(const char* tag, const XMLAttributes& a)
+{
+    if(naIsNil(_start_element)) return;
+    naRef attr = naNewHash(_c);
+    for(int i=0; i<a.size(); i++) {
+        naRef name = make_string(a.getName(i));
+        naRef value = make_string(a.getValue(i));
+        naHash_set(attr, name, value);
     }
-    nas->deleteModule(_module.c_str());
+    call(_start_element, 2, make_string(tag), attr);
+}
+
+void NasalXMLVisitor::endElement(const char* tag)
+{
+    if(!naIsNil(_end_element)) call(_end_element, 1, make_string(tag));
+}
+
+void NasalXMLVisitor::data(const char* str, int len)
+{
+    if(!naIsNil(_data)) call(_data, 1, make_string(str, len));
+}
+
+void NasalXMLVisitor::pi(const char* target, const char* data)
+{
+    if(!naIsNil(_pi)) call(_pi, 2, make_string(target), make_string(data));
+}
+
+void NasalXMLVisitor::call(naRef func, int num, naRef a, naRef b)
+{
+    naRef args[2];
+    args[0] = a;
+    args[1] = b;
+    naCall(_c, func, num, args, naNil(), naNil());
+    if(naGetError(_c))
+        naRethrowError(_c);
+}
+
+naRef NasalXMLVisitor::make_string(const char* s, int n)
+{
+    return naStr_fromdata(naNewString(_c), const_cast<char *>(s),
+                          n < 0 ? strlen(s) : n);
 }