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# events.nas - Generic objects for managing events
#
# Copyright (C) 2014 Anton Gomez Alvedro
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
# The EventDispatcher is a simple helper object that keeps a list of listeners
# and allows a calling entity to send an "event" object to all subscribers.
#
# It is intended to be used internally by modules that want to offer a
# subscription interface so other modules can receive notifications.
# For an example of how to use it this way, check Nasal/FailureMgr
var EventDispatcher = (func {
var global_id = 0;
var getid = func { global_id += 1 };
return {
new: func {
var m = { parents: [EventDispatcher] };
m._subscribers = {};
return m;
},
notify: func(event) {
foreach(var id; keys(me._subscribers))
me._subscribers[id](event);
},
subscribe: func(callback) {
assert(typeof(callback) == "func");
var id = getid();
me._subscribers[id] = callback;
return id;
},
unsubscribe: func(id) {
delete(me._subscribers, id);
}
};
})();
##
# Stores messages in a circular buffer that then can be retrieved at any point.
# Messages are time stamped when pushed into the buffer, and the time stamp is
# kept by the message.
var LogBuffer = {
new: func (max_messages = 128, echo = 0) {
assert(max_messages > 1, "come on, lets be serious..");
var m = { parents: [LogBuffer] };
m.echo = echo;
m.max_messages = max_messages;
m.buffer = setsize([], max_messages);
m.full = m.wp = 0;
return m;
},
push: func(message) {
var stamp = getprop("/sim/time/gmt-string");
if (me.echo) print(stamp, " ", message);
me.buffer[me.wp] = { time: stamp, message: message };
me.wp += 1;
if (me.wp == me.max_messages) {
me.wp = 0;
me.full = 1;
}
},
clear: func {
me.full = me.wp = 0;
},
##
# Returns a vector with all messages, starting with the oldest one.
# Each vector entry is a hash with the format:
# { time: <timestamp_str>, message: <the message> }
get_buffer: func {
if (me.full)
!me.wp ? me.buffer : me.buffer[me.wp:-1] ~ me.buffer[0:me.wp-1];
elsif (me.wp == 0)
[];
else
me.buffer[0:me.wp-1];
}
};