we know the stack trace), it's better to use a separate function for
it, as this can be used conditionally, as in:
setlistener("/the/property", func(n) {
if (n.getValue() < 0) # who's writing negative numbers to /the/property?!
abort(); # let's check the backtrace ...
});
and its function called. This is useful for debugging purposes, to get
a core dump which unveils which C++ code was writing to the property.
This isn't any more of a security problem as other Nasal code that
makes fgfs crash, such as: var x = func call(x); x(); The difference
is that the listener doesn't use up all memory before and is much quicker.
From Till:
i started the project at the end of february with a simple idea: move all
3d-model loading to the DatabasePager-thread. my first attempts looked
promising, though they were a little too optimistic (or naive?). the patch
has evolved a lot since.
currently it does the following things:
1. revive SGModelLib, move functions for xml-model-loading there
2. replace all calls to sgLoad3dModel with calls to either
SGModelLib::loadModel() or SGModelLib::loadPagedModel()
almost all models will be loaded by the DatabasePager. the few exceptions are:
your own plane, shared models in scenery, random objects, AIBallistic models.
3. simplify mode-loading functions (avoid passing around fg_root)
4. avoid supurious MatrixTransform nodes in loaded models
5. fix some memory leaks
invocations, but left it in place for miscellaneous allocation work.
Contexts cache allocated objects in a temps vector and only clear it
out when they are used.
Also, fix a type warning while I'm in there.
- simplify listener purging and fix removelistener() return value for
one-shot listeners
- listener: inherit virtualness
- s/handler/code/ in listener code to be consistent with NasalSys::call
argument:
setlistener(<property>, <func> [, <initial=0> [, <persistent=1>]])
This definition defaults to the old behavior. The fourth argument can
be set to zero, in which case the function is only called when the
node value has actually changed. It should really default to zero, but
then all callers would have to be reviewed, which is a bit too dangerous
"shortly" before a release.
0 -> trigger whenever property is written to (even if it's the old value; default)
1 -> like 0, but also trigger the function initially
2 -> trigger initially, but then only on changes
the next airport or airport with METAR station, but about any type of
airport
- as a side effect this change makes it also 30 to 50% faster :-)
In the long run this linear search shall be replaced with a spatial
algorithm (like octree), which will be a much bigger performance gain.
Usage: airportinfo("KSFO");
airportinfo(37, 122); # airport closest to lat/lon
airportinfo(); # airport closest to current position
Returns nil on error, or a data hash otherwise. Example:
# length of runway 28R
var len = airportinfo("KSFO").runways["10L"].length;
Note that only one side of a runway is returned.
parser. Advantages over xml.nas: (reviewed and OK'ed by Andy)
- faster (33% ... only. I had hoped for more.)
- more standards compliant
- should support UTF
- I don't have to support it. ;-)
Usage: parsexml(<path> [, <start-tag> [, <end-tag> [, <data> [, <pi>]]]]);
<path> is an absolute file path, the rest are optional callback functions.
Example:
parsexml("/tmp/foo.xml", nil, nil, func(d) { print("DATA FOUND: ", d) });
or nil if no terrain intersection could be made (tile not loaded yet).
<matdata> is a hash with information about the surface material, or nil
if no material is assigned (shouldn't really happen, but one never knows).
Example:
var ac = geo.aircraft_position();
var data = geoddata(ac.lat(), ac.lon());
debug.dump(data);
# which outputs
[ 294.5862574369132, { light_coverage : 0, bumpiness : 0, load_resistance : 1e+30,
solid : 1, names : [ "pc_taxiway", "dirt_rwytaxiway" ], friction_factor : 1,
rolling_friction : 0.02 } ]
With this information it can be determined how far an object would sink in,
if the coordinate is on a runway, etc.
foreach (var n; data[1].names)
if (string.match(n, "p[ac]_*"))
im_on_a_runway();
IRC wanted this to be scritable) and add it back (as a tip popup) via
a little nasal in the keyboard handler. Also put the synthesis of
property nodes back into fgcommand(), because I got cold feet.
missing, for sanity. Note that this will pass the resulting NULL
pointer through into the underlying SGCommand handlers, some of which
may be unprepared for it. So basically this is now yet another way
you can use Nasal to exercise bugs and hose your sim; no biggie.
because nasal's f_interpolate() may be called in Nasal at times when the
GENERAL subsystem group is being deconstructed; access it by addressing
the group directly, as using globals->get_subsystem() does then not
work any more then; yeah, it's all for a rare border case ... :-)
NasalSys.cxx more robust instead. The reason for the crash was that during
fgfs shutdown destroyed subsystems (GENERAL group) still need Nasal access
(for AI Model destruction listeners), but at that point globals->get_subsystem()
can't even deliver the "nasal" subsystem (INIT group). One way to solve that
problem would have been to replace globals->get_subsystem("nasal") by
globals->get_subsystem_mgr()->get_group(SGSubsystemMgr::INIT)->get_subsystem("nasal"),
but Andy decided to store a pointer to the active "nasal" subsysten in
NasalSys.cxx instead, as the "nasal" subsystem needs to be accessed in
every single Nasal extension function, and multiple "nasal" subsystems are
out of the question, anyway.
their XML wrapper/animation file. They can access their /ai/models node
via cmdarg() function. Example:
<nasal>
<load>
print("Hi, I'm the Nimitz. My data are under ",
cmdarg().getPath());
</load>
<unload>
...
</unload>
</nasal>
Note, however, that the <unload> block is only called on exit at the moment,
not when the tile is unloaded.
Nasal now supports calls to "subcontexts" and errors can be thrown
across them, leading to complete stack traces when call() is used,
instead of the truncated ones we now see.
Vectors can now be concatenated using the ~ operator that used to work
only for strings.
Better runtime error messages in general due to a fancier
naRuntimeError() implementation
A big data size shrink on 64 bit systems; the size of a naRef dropped
by a factor of two.
"Braceless code blocks" have been added to the parser, so you can
write expressions like "if(a) b();" just like in C. Note that there's
still a parser bug in there that fails when you nest a braced block
within a braceless one.
Character constants that appear in Nasal source code can now be
literal multibyte UTF8 characters (this was always supported for
string literals, but character constants were forced to be a single
byte).
New modules: "bits", "thread", "utf8" and (gulp...) "io". The bits
library might be useful to FlightGear, the utf8 one probably not as
Plib does not support wide character text rendering. The thread
library will work fine for spawning threads to do Nasal stuff, but
obviously contact with the rest of FlightGear must be
hand-synchronized as FlightGear isn't threadsafe. The io library is
no doubt the most useful, as it exposes all the basic stdio.h
facilities; it's also frighteningly dangerous when combined with
networked code...
done for performance reasons, but print() should be able to output any
valid string, and when SG_LOG uses strings and streams already, then we
can use that here, too. (Not discussed with Andy yet.)
