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Add-ons: small fixes to Nasal/addons.nas and Docs/README.add-ons

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+ After discussion with Henning:
    - orig_setlistener() and orig_maketimer() were not intended to be
      public -> prefix the function names with an underscore;
    - clear the add-on's lists of tracked listeners and timers in
      remove() (load() does that too, but it's a bit late).

+ Little rewording in Docs/README.add-ons.
This commit is contained in:
Florent Rougon 2018-12-10 15:24:03 +01:00
parent f3548c561e
commit 02b01af19e
2 changed files with 28 additions and 23 deletions
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31
Docs/README.add-ons
View file

@ -840,13 +840,15 @@ Read-only data members (attributes) of addons.Maintainer objects:
!!! We really don't want users to send bug reports due to reload going wrong.
To make development of add-ons less time consuming, you can reload the
Nasal part of your add-on without having to restart FlightGear. The
addons.nas module will track setlistener() and maketimer() calls for
your add-on and remove listeners and stop timers on reload for you (the
add-on's own namespace, has setlistener() and maketimer() wrappers that
shadow and call themselves the standard setlistener() and maketimer()
functions).
Nasal part of your add-on without having to restart FlightGear. When an
add-on is loaded, setlistener() and maketimer() wrappers are installed
in the add-on's own namespace; these wrappers shadow and call themselves
the standard setlistener() and maketimer() functions. The setlistener()
and maketimer() wrapper functions keep track of every listener and timer
they create. When the add-on is removed (e.g., as part of its reload
sequence), removelistener() is called for each of these listeners, and
each timer has its stop() method called.
_
For the time being, you have to track any other resources outside the
namespace of your add-on by yourself and clean them up in the unload()
function, e.g. delete canvas or close any files you opened.
@ -855,14 +857,15 @@ You can define this unload() function in the addon-main.nas file. When
your add-on is reloaded, its unload() function, if defined, will be
called with one argument: the addons.Addon object (a Nasal ghost)
corresponding to your add-on. unload() is run in the add-on's own
namespace, therefore it sees the aforementioned setlistener() and
maketimer() wrapper functions.
namespace.
The reload is triggered by setting /addon/by-id/yourAddonIDhere/reload
to true. A listener will react to that property, reset it to false and
attempt to reload the Nasal file (doing the cleanup before). You can add
a menu item to trigger the reload easily, but this should be removed
before publishing your add-on to users.
The reload is triggered by setting the property
/addon/by-id/ADDON_ID/reload to true (replace ADDON_ID with your
particular add-on identifier). A listener will react to that property,
reset it to false and attempt to reload the addon-main.nas file for your
add-on (doing the aforementioned cleanup before). You can add a menu
item to trigger the reload easily, but it should be removed before
publishing your add-on to users (see the above warning).
Please have a look at the skeleton add-on at
https://sourceforge.net/p/flightgear/fgaddon/HEAD/tree/trunk/Addons/Skeleton/

20
Nasal/addons.nas
View file

@ -32,8 +32,8 @@
# hashes to store listeners and timers per addon ID
var _listeners = {};
var _timers = {};
var orig_setlistener = nil;
var orig_maketimer = nil;
var _orig_setlistener = nil;
var _orig_maketimer = nil;
var getNamespaceName = func(a) {
return "__addon[" ~ a.id ~ "]__";
@ -61,16 +61,16 @@ var load = func(a) {
p = p.getAliasTarget();
}
}
append(_listeners[a.id], orig_setlistener(p, f, start, runtime));
append(_listeners[a.id], _orig_setlistener(p, f, start, runtime));
print("#listeners for " ~ a.id ~ " " ~ size(_listeners[a.id]));
}
# redirect maketimer for addon
globals[namespace].maketimer = func() {
if (size(arg) == 2) {
append(_timers[a.id], orig_maketimer(arg[0], arg[1]));
append(_timers[a.id], _orig_maketimer(arg[0], arg[1]));
} elsif (size(arg) == 3) {
append(_timers[a.id], orig_maketimer(arg[0], arg[1], arg[2]));
append(_timers[a.id], _orig_maketimer(arg[0], arg[1], arg[2]));
} else {
print("Invalid number of arguments to maketimer()");
return;
@ -107,17 +107,19 @@ var remove = func(a) {
print("- Removing ", a.id);
var namespace = getNamespaceName(a);
foreach (var id; _listeners[a.id]) {
print(" Remove listener " ~ id);
print(" Removing listener " ~ id);
removelistener(id);
}
_listeners[a.id] = [];
print(" Stopping timers ");
foreach (var t; _timers[a.id]) {
if (typeof(t.stop) == "func") {
t.stop();
print(".");
print(" .");
}
}
_timers[a.id] = [];
# call clean up method if available
# addon shall release resources not handled by addon framework
@ -154,7 +156,7 @@ var init = func {
var id = _setlistener("/sim/signals/fdm-initialized", func {
removelistener(id);
orig_setlistener = setlistener;
orig_maketimer = maketimer;
_orig_setlistener = setlistener;
_orig_maketimer = maketimer;
addons.init();
})