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#-------------------------------------------------------------------------------
# modules.nas - Nasal module helper for Add-ons and re-loadable modules
# author: jsb
# created: 12/2019
#-------------------------------------------------------------------------------
# modules.nas allowes to load and unload Nasal modules at runtime (e.g. without
# restarting Flightgear as a whole). It implements resource tracking for
# setlistener and maketimer to make unloading easier
#-------------------------------------------------------------------------------
# Example - generic module load:
#
# if (modules.isAvailable("foo_bar")) {
# modules.load("foo_bar");
# }
#
# Example - create an aircraft nasal system as module
# (e.g. for rapid reload while development)
#
# var my_foo_sys = modules.Module.new("my_aircraft_foo");
# my_foo_sys.setDebug(1);
# my_foo_sys.setFilePath(getprop("/sim/aircraft-dir")~"/Nasal");
# my_foo_sys.setMainFile("foo.nas");
# my_foo_sys.load();
#-------------------------------------------------------------------------------
var MODULES_DIR = getprop("/sim/fg-root")~"/Nasal/Modules/";
var MODULES_NODE = nil;
var _modules_available = {};
var _instances = {};
# Class to handle a nasal module at runtime
var Module = {
_orig_setlistener: setlistener,
_orig_maketimer: maketimer,
_orig_settimer: settimer,
# id: must be a string without special characters or spaces
# ns: optional namespace name
# node: optional property node for module management
new: func(id, ns = "", node = nil) {
if (!id) {
id = "_module_manager";
}
if (_instances[id] != nil) {
return _instances[id];
}
var obj = {
parents: [me],
_listeners: [],
_timers: [],
_debug: 0,
id: id,
version: 1,
file_path: MODULES_DIR,
main_file: "main.nas",
namespace: ns ? ns : id,
node: nil,
};
if (isa(node, props.Node)) {
obj.node = node
} else {
obj.node = MODULES_NODE.getNode(id, 1);
}
obj.reloadN = obj.node.initNode("reload", 0, "BOOL");
obj.loadedN = obj.node.initNode("loaded", 0, "BOOL");
obj.lcountN = obj.node.initNode("listeners", 0, "INT");
obj.tcountN = obj.node.initNode("timers", 0, "INT");
obj.lhitN = obj.node.initNode("listener-hits", 0, "INT");
setlistener(obj.reloadN, func(n) {
if (n.getValue()) {
n.setValue(0);
obj.reload();
}
});
return obj;
},
getNode: func { return me.node; },
getReloadNode: func { return me.reloadN; },
getNamespaceName: func { return me.namespace; },
getNamespace: func { return globals[me.namespace]; },
getFilePath: func { return me.file_path; },
#return variable from module namespace
get: func(var_name) {
return globals[me.namespace][var_name];
},
setDebug: func (debug = 1) {
me._debug = debug;
logprint(4, "Module "~me.id~" debug = "~debug);
},
setFilePath: func(path) {
if (io.is_directory(path)) {
if (substr(path, -1) != "/")
path ~= "/";
me.file_path = path;
return 1;
}
return 0;
},
setMainFile: func(filename) {
if (typeof(filename) == "scalar") {
me.main_file = filename;
}
else {
logprint("4", "setMainFile() needs a string parameter");
}
},
setNamespace: func(ns) {
if (typeof(ns) == "scalar") {
me.namespace = ns;
}
else {
logprint("4", "setNamespace() needs a string parameter");
}
},
# load module
# if no arguments are given, the Module object will be passed to main()
load: func(myargs...) {
me.loadedN.setBoolValue(0);
if (globals[me.namespace] == nil) {
globals[me.namespace] = {};
}
logprint(5, "Module.load() ", me.id);
me._redirect_setlistener();
me._redirect_maketimer();
me._redirect_settimer();
var filename = me.file_path~"/"~me.main_file;
if (io.load_nasal(filename, me.namespace)) {
var main = globals[me.namespace]["main"];
if (typeof(main) == "func") {
var module_args = [];
if (size(myargs) == 0) module_args = [me];
else module_args = myargs;
var errors = [];
call(main, module_args, errors);
if (size(errors)) {
debug.printerror(errors);
} else {
me.loadedN.setBoolValue(1);
}
} else {
me.loadedN.setBoolValue(1);
}
return me;
}
else { return nil; }
},
#-- unload a module and its tracked resources --
unload: func() {
if (!me.loadedN.getValue()) {
logprint(5, "! ", me.id, " was not fully loaded.");
}
if (globals[me.namespace] != nil
and typeof(globals[me.namespace]) == "hash")
{
logprint(5, "- Removing module ", me.id);
if (globals[me.namespace]["setlistener"] != nil)
globals[me.namespace]["setlistener"] = func {};
foreach (var id; me._listeners) {
logprint(3, "Removing listener "~id);
removelistener(id);
}
me._listeners = [];
logprint(3, "Stopping timers ");
if (globals[me.namespace]["maketimer"] != nil)
globals[me.namespace]["maketimer"] = func {};
foreach (var t; me._timers) {
if (typeof(t.stop) == "func") {
t.stop();
logprint(2, " .");
}
}
me._timers = [];
# call clean up method if available
# module shall release resources not handled by this framework
if (globals[me.namespace]["unload"] != nil
and typeof(globals[me.namespace]["unload"]) == "func") {
var errors = [];
call(globals[me.namespace].unload, [me], errors);
if (size(errors)) {
debug.printerror(errors);
}
}
me.loadedN.setBoolValue(0);
#kill namespace (replace with empty hash and hope GC cleans up behind us)
globals[me.namespace] = nil;
}
},
reload: func() {
me.unload();
me.load();
},
printTrackedResources: func(loglevel = 3) {
logprint(loglevel, "Tracked resources after running the main() function of " ~
me.id~":");
logprint(loglevel, "#listeners: "~size(me._listeners));
logprint(loglevel, "#timers: "~size(me._timers));
logprint(loglevel, "Use log level DEBUG to see all calls to the " ~
"setlistener() and maketimer() wrappers.");
},
# redirect setlistener() for module
_redirect_setlistener: func() {
globals[me.namespace].setlistener = func(p, f, start=0, runtime=0) {
if (!isa(p, props.Node)) {
p = props.getNode(p, 1).resolveAlias();
}
if (me._debug) {
var f_debug = func {
me.lhitN.setValue(me.lhitN.getValue() + 1);
print("Listener hit for: ", p.getPath());
call(f, arg);
};
append(me._listeners, Module._orig_setlistener(p, f_debug, start, runtime));
var c = caller(1);
if (c != nil) {
print(sprintf("setlistener for %s called from %s:%s",
p.getPath(), io.basename(c[2]), c[3]));
};
} else {
append(me._listeners, Module._orig_setlistener(p,
f, start, runtime));
}
me.lcountN.setValue(me.lcountN.getValue() + 1);
}
me.setlistener = globals[me.namespace].setlistener;
},
# redirect maketimer for module
_redirect_maketimer: func() {
globals[me.namespace].maketimer = func() {
if (size(arg) == 2) {
append(me._timers, Module._orig_maketimer(arg[0], arg[1]));
} elsif (size(arg) == 3) {
append(me._timers,
Module._orig_maketimer(arg[0], arg[1], arg[2]));
} else {
logprint(5, "Invalid number of arguments to maketimer()");
return;
}
if (me._debug) {
var c = caller(1);
if (c != nil) {
print(sprintf("maketimer called from %s:%s",
io.basename(c[2]), c[3]));
};
}
me.tcountN.setValue(me.tcountN.getValue() + 1);
return me._timers[-1];
}
me.maketimer = globals[me.namespace].maketimer;
},
_redirect_settimer: func() {
globals[me.namespace].settimer = func() {
var c = caller(1);
logprint(5, sprintf("\n\Unsupported settimer() call from %s:%s. "~
"Use maketimer() instead.",
io.basename(c[2]), c[3]));
}
},
};
var isAvailable = func(name) {
return contains(_modules_available, name);
}
var _getInstance = func(name) {
if (isAvailable(name) and _instances[name] == nil) {
var m = Module.new(name);
m.setFilePath(MODULES_DIR~name);
_instances[name] = m;
}
return _instances[name];
}
var setDebug = func(name, debug=1) {
if (isAvailable(name)) {
var module = _getInstance(name);
module.setDebug(debug);
}
}
var load = func(name, ns="") {
var m = _getInstance(name);
if (m != nil) {
if (ns) { m.setNamespace(ns); }
return m.load();
}
else return 0;
}
# scan MODULES_DIR for subdirectories; it is assumed, that only well-formed
# modules are stored in that directories, so no further checks right here
var _findModules = func() {
var module_dirs = io.subdirectories(MODULES_DIR);
_modules_available = {};
foreach (var name; module_dirs) {
_modules_available[name] = 1;
}
}
_setlistener("sim/signals/nasal-dir-initialized", func {
MODULES_NODE = props.getNode("/nasal/modules", 1);
_findModules();
});