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fgdata/Nasal/emesary.nas
Richard Harrison 405eb73bb6 Emesary multiplayer bridge rework. 
The primary goal of this work is to provide a alternative to multiplayer property transmission, one that is more efficient and event driven. By using notifications in the model bindings these control messages can be bridged and do not require extra code to implement dual controls.

Using this alternative permits the modeller much greater control of which properties are transmitted, how these are encoded, and how often the updates are needed.

Please remember that this is a use case for Emesary, it is not all that Emesary can provide and there are still many other uses for the event driven object oriented system that Emesary provides.

Briefly the changes are:

- New PropertySyncNotificationBase to permit property transfer between ownship and MP versions using notifications instead of the pre-defined MP messages. This gives a much more flexible way to seutp multiplayer property transfer - and can probably support more properties because of the more efficient packing. There is a corresponding parameter (/sim/multiplay/transmit-only-generics) that will only transmit the bare minimum of parameters; making more space for notifications.

- new AircraftControlNotification to allow for animation bindings in the model, these notifications can be easily bridged over MP thus adding a simple method to implement dual controls.

- more efficient packing of encoded notifications over MP saving roughly 30% (by using a much larger encoding space and also changing to use fixed length encoding). This breaks compatibility with previous MP bridges, however at this time I don't think anything is using the current code.

There can be different types of PropertySyncNotification (with unique ID's) sent at a different schedule (so you could have a 10 second update of very slow moving items). However bear in mind that the messages have a lifetime of 10 seconds to ensure receipt - so to optimise space would require > 15 seconds to make much difference, and that is very slow moving.
2017-07-23 16:05:43 +02:00

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#---------------------------------------------------------------------------
#
# Title : EMESARY inter-object communication
#
# File Type : Implementation File
#
# Description : Provides generic inter-object communication. For an object to receive a message it
# : must first register with an instance of a Transmitter, and provide a Receive method
#
# : To send a message use a Transmitter with an object. That's all there is to it.
#
# References : http://chateau-logic.com/content/emesary-nasal-implementation-flightgear
# : http://www.chateau-logic.com/content/class-based-inter-object-communication
# : http://chateau-logic.com/content/emesary-efficient-inter-object-communication-using-interfaces-and-inheritance
# : http://chateau-logic.com/content/c-wpf-application-plumbing-using-emesary
#
# Author : Richard Harrison (richard@zaretto.com)
#
# Creation Date : 29 January 2016
#
# Version : 4.8
#
# Copyright © 2016 Richard Harrison Released under GPL V2
#
#---------------------------------------------------------------------------*/
var __emesaryUniqueId = 14; # 0-15 are reserved, this way the global transmitter will be 15.
# Transmitters send notifications to all recipients that are registered.
var Transmitter =
{
ReceiptStatus_OK : 0, # Processing completed successfully
ReceiptStatus_Fail : 1, # Processing resulted in at least one failure
ReceiptStatus_Abort : 2, # Fatal error, stop processing any further recipieints of this message. Implicitly failed.
ReceiptStatus_Finished : 3, # Definitive completion - do not send message to any further recipieints
ReceiptStatus_NotProcessed : 4,# Return value when method doesn't process a message.
ReceiptStatus_Pending : 5, # Message sent with indeterminate return status as processing underway
ReceiptStatus_PendingFinished : 6,# Message definitively handled, status indeterminate. The message will not be sent any further
# create a new transmitter. shouldn't need many of these
new: func(_ident)
{
var new_class = { parents: [Transmitter]};
new_class.Recipients = [];
new_class.Ident = _ident;
__emesaryUniqueId += 1;
new_class.UniqueId = __emesaryUniqueId;
return new_class;
},
# Add a recipient to receive notifications from this transmitter
Register: func (recipient)
{
append(me.Recipients, recipient);
},
# Stops a recipient from receiving notifications from this transmitter.
DeRegister: func(todelete_recipient)
{
var out_idx = 0;
var element_deleted = 0;
for (var idx = 0; idx < size(me.Recipients); idx += 1)
{
if (me.Recipients[idx] != todelete_recipient)
{
me.Recipients[out_idx] = me.Recipients[idx];
out_idx = out_idx + 1;
}
else
element_deleted = 1;
}
if (element_deleted)
pop(me.Recipients);
},
RecipientCount: func
{
return size(me.Recipients);
},
PrintRecipients: func
{
print("Emesary: Recipient list for ",me.Ident,"(",me.UniqueId,")");
for (var idx = 0; idx < size(me.Recipients); idx += 1)
print("Emesary: Recipient[",idx,"] ",me.Recipients[idx].Ident," (",me.Recipients[idx].UniqueId,")");
},
# Notify all registered recipients. Stop when receipt status of abort or finished are received.
# The receipt status from this method will be
# - OK > message handled
# - Fail > message not handled. A status of Abort from a recipient will result in our status
# being fail as Abort means that the message was not and cannot be handled, and
# allows for usages such as access controls.
NotifyAll: func(message)
{
var return_status = Transmitter.ReceiptStatus_NotProcessed;
foreach (var recipient; me.Recipients)
{
if (recipient.RecipientActive)
{
var rstat = recipient.Receive(message);
if(rstat == Transmitter.ReceiptStatus_Fail)
{
return_status = Transmitter.ReceiptStatus_Fail;
}
elsif(rstat == Transmitter.ReceiptStatus_Pending)
{
return_status = Transmitter.ReceiptStatus_Pending;
}
elsif(rstat == Transmitter.ReceiptStatus_PendingFinished)
{
return rstat;
}
# elsif(rstat == Transmitter.ReceiptStatus_NotProcessed)
# {
# ;
# }
elsif(rstat == Transmitter.ReceiptStatus_OK)
{
if (return_status == Transmitter.ReceiptStatus_NotProcessed)
return_status = rstat;
}
elsif(rstat == Transmitter.ReceiptStatus_Abort)
{
return Transmitter.ReceiptStatus_Abort;
}
elsif(rstat == Transmitter.ReceiptStatus_Finished)
{
return Transmitter.ReceiptStatus_OK;
}
}
}
return return_status;
},
# Returns true if a return value from NotifyAll is to be considered a failure.
IsFailed: func(receiptStatus)
{
# Failed is either Fail or Abort.
# NotProcessed isn't a failure because it hasn't been processed.
if (receiptStatus == Transmitter.ReceiptStatus_Fail or receiptStatus == Transmitter.ReceiptStatus_Abort)
return 1;
return 0;
}
};
#
#
# Base class for Notifications. By convention a Notification has a type and a value.
# SubClasses can add extra properties or methods.
# Properties:
# Ident : Generic message identity. Can be an ident, or for simple messages a value that needs transmitting.
# NotificationType : Notification Type
# IsDistinct : non zero if this message supercedes previous messages of this type.
# Distinct messages are usually sent often and self contained
# (i.e. no relative state changes such as toggle value)
# Messages that indicate an event (such as after a pilot action)
# will usually be non-distinct. So an example would be gear/up down
# or ATC acknowledgements that all need to be transmitted
# The IsDistinct is important for any messages that are bridged over MP as
# only the most recently sent distinct message will be transmitted over MP
var NotificationAutoTypeId = 1;
var Notification =
{
new: func(_type, _ident, _typeid=0)
{
var new_class = { parents: [Notification]};
new_class.Ident = _ident;
new_class.NotificationType = _type;
new_class.IsDistinct = 1;
new_class.FromIncomingBridge = 0;
new_class.Callsign = nil;
if (_typeid == 0)
{
_typeid = NotificationAutoTypeId;
NotificationAutoTypeId = NotificationAutoTypeId + 1;
}
new_class.TypeId = _typeid;
return new_class;
},
};
# Inherit or implement class with the same signatures to receive messages.
var Recipient =
{
new: func(_ident)
{
var new_class = { parents: [Recipient]};
if (_ident == nil or _ident == "")
{
_ident = id(new_class);
print("Emesary Error: Ident required when creating a recipient, defaulting to ",_ident);
}
Recipient.construct(_ident, new_class);
},
construct: func(_ident, new_class)
{
new_class.Ident = _ident;
new_class.RecipientActive = 1;
__emesaryUniqueId += 1;
new_class.UniqueId = __emesaryUniqueId;
new_class.Receive = func(notification)
{
# warning if required function not
print("Emesary Error: Receive function not implemented in recipient ",me.Ident);
return Transmitter.ReceiptStatus_NotProcessed;
};
return new_class;
},
};
#
# Instantiate a Global Transmitter, this is a convenience and a known starting point. Generally most classes will
# use this transmitters, however other transmitters can be created and merely use the global transmitter to discover each other
var GlobalTransmitter = Transmitter.new("GlobalTransmitter");
#
#
# This is basically a base64 like encode except we just use alphanumerics which gives us a base62 encode.
var BinaryAsciiTransfer =
{
# alphabet : "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
alphabet : chr(1)~chr(2)~chr(3)~chr(4)~chr(5)~chr(6)~chr(7)~chr(8)~chr(9)~chr(10)~chr(11)~chr(12)~chr(13)
~chr(14)~chr(15)~chr(16)~chr(17)~chr(18)~chr(19)~chr(20)~chr(21)~chr(22)~chr(23)~chr(24)~chr(25)
~chr(26)~chr(27)~chr(28)~chr(29)~chr(30)~chr(31)~chr(34)
~"%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}"
~chr(128)~chr(129)~chr(130)~chr(131)~chr(132)~chr(133)~chr(134)~chr(135)~chr(136)~chr(137)~chr(138)
~chr(139)~chr(140)~chr(141)~chr(142)~chr(143)~chr(144)~chr(145)~chr(146)~chr(147)~chr(148)~chr(149)
~chr(150)~chr(151)~chr(152)~chr(153)~chr(154)~chr(155)~chr(156)~chr(157)~chr(158)~chr(159)~chr(160)
~chr(161)~chr(162)~chr(163)~chr(164)~chr(165)~chr(166)~chr(167)~chr(168)~chr(169)~chr(170)~chr(171)
~chr(172)~chr(173)~chr(174)~chr(175)~chr(176)~chr(177)~chr(178)~chr(179)~chr(180)~chr(181)~chr(182)
~chr(183)~chr(184)~chr(185)~chr(186)~chr(187)~chr(188)~chr(189)~chr(190)~chr(191)~chr(192)~chr(193)
~chr(194)~chr(195)~chr(196)~chr(197)~chr(198)~chr(199)~chr(200)~chr(201)~chr(202)~chr(203)~chr(204)
~chr(205)~chr(206)~chr(207)~chr(208)~chr(209)~chr(210)~chr(211)~chr(212)~chr(213)~chr(214)~chr(215)
~chr(216)~chr(217)~chr(218)~chr(219)~chr(220)~chr(221)~chr(222)~chr(223)~chr(224)~chr(225)~chr(226)
~chr(227)~chr(228)~chr(229)~chr(230)~chr(231)~chr(232)~chr(233)~chr(234)~chr(235)~chr(236)~chr(237)
~chr(238)~chr(239)~chr(240)~chr(241)~chr(242)~chr(243)~chr(244)~chr(245)~chr(246)~chr(247)~chr(248)
~chr(249)~chr(250)~chr(251)~chr(252)~chr(253)~chr(254)~chr(255),
_base: 248,
spaces: " ",
empty_encoding: chr(1)~chr(1)~chr(1)~chr(1)~chr(1)~chr(1)~chr(1)~chr(1)~chr(1)~chr(1)~chr(1),
encodeInt : func(num,length)
{
if (num == 0)
return substr(BinaryAsciiTransfer.empty_encoding,0,length);
var arr="";
while (num > 0 and length > 0) {
var num0 = num;
num = (int)(num / BinaryAsciiTransfer._base);
rem = num0-(num*BinaryAsciiTransfer._base);
arr =substr(BinaryAsciiTransfer.alphabet, rem,1) ~ arr;
length -= 1;
}
if (length>0)
arr = substr(BinaryAsciiTransfer.spaces,0,length)~arr;
return arr;
},
retval : {value:0, pos:0},
decodeInt : func(str, length, pos)
{
var power = length-1;
BinaryAsciiTransfer.retval.value = 0;
BinaryAsciiTransfer.retval.pos = pos;
while (length > 0 and power > 0) {
var c = substr(str,BinaryAsciiTransfer.retval.pos,1);
if (c != " ") break;
power = power -1;
length = length-1;
BinaryAsciiTransfer.retval.pos = BinaryAsciiTransfer.retval.pos + 1;
}
while (length >= 0 and power >= 0) {
var c = substr(str,BinaryAsciiTransfer.retval.pos,1);
# spaces are used as padding so ignore them.
if (c != " ") {
var cc = find(c,BinaryAsciiTransfer.alphabet);
if (cc < 0)
{
print("Emesary: BinaryAsciiTransfer.decodeInt: Bad encoding ");
return BinaryAsciiTransfer.retval;
}
BinaryAsciiTransfer.retval.value += int(cc * math.exp(math.ln(BinaryAsciiTransfer._base) * power));
power = power - 1;
}
length = length-1;
BinaryAsciiTransfer.retval.pos = BinaryAsciiTransfer.retval.pos + 1;
}
return BinaryAsciiTransfer.retval;
}
};
var TransferString =
{
#
# just to pack a valid range and keep the lower and very upper control codes for seperators
# that way we don't need to do anything special to encode the string.
getalphanumericchar : func(v)
{
if (find(v,"-./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_abcdefghijklmnopqrstuvwxyz") > 0)
return v;
return nil;
},
encode : func(v)
{
if (v==nil)
return "0";
var l = size(v);
if (l > 16)
l = 16;
var rv = BinaryAsciiTransfer.encodeInt(l,1);
for(var ii = 0; ii < l; ii = ii + 1)
{
ev = TransferString.getalphanumericchar(substr(v,ii,1));
if (ev != nil)
rv = rv ~ ev;
}
return rv;
},
decode : func(v,pos)
{
var dv = BinaryAsciiTransfer.decodeInt(v,1,pos);
var length = dv.value;
var rv = substr(v,dv.pos,length);
dv.pos = dv.pos + length;
dv.value = rv;
return dv;
}
};
#
# encode an int into a specified number of characters.
var TransferInt =
{
encode : func(v, length)
{
return BinaryAsciiTransfer.encodeInt(v,length);
},
decode : func(v, length, pos)
{
return BinaryAsciiTransfer.decodeInt(v,length,pos);
}
};
var TransferFixedDouble =
{
po2: [1.0,124.0,30752.0,7626496.0,1891371008.0,469060009984.0,116326882476032.0,28849066854055936.0], # needs to match powers of BinaryAsciiTransfer._base
encode : func(v, length, factor)
{
var scale = int(me.po2[length] / factor);
var v = int(v * factor);
if (v < -scale) v = -scale;
else if (v > scale) v = scale;
return BinaryAsciiTransfer.encodeInt(int(v), length);
},
decode : func(v, length, factor, pos)
{
var scale = int(me.po2[length] / factor);
var dv = BinaryAsciiTransfer.decodeInt(v, length, pos);
dv.value = (int(dv.value)/factor);
return dv;
}
};
var TransferNorm =
{
powers: [1,10.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, 10000000.0, 100000000.0, 1000000000.0, 10000000000.0, 100000000000.0],
po2: [1.0,123.0,30751.0,7626495.0,1891371007,469060009983,116326882476031,28849066854055935], # needs to match powers of BinaryAsciiTransfer._base
encode : func(v, length)
{
v = v + 1;
if(v>2)
v=2;
else if (v < 0)
v=0;
return BinaryAsciiTransfer.encodeInt(int(v * me.po2[length]),length);
},
decode : func(v, length, pos)
{
dv = BinaryAsciiTransfer.decodeInt(v, length,pos);
dv.value = (dv.value/me.po2[length]) - 1;
return dv;
}
};
var TransferByte =
{
encode : func(v)
{
return BinaryAsciiTransfer.encodeInt(v,1);
},
decode : func(v, pos)
{
return BinaryAsciiTransfer.decodeInt(v, 1,pos);
}
};
var TransferCoord =
{
# 28 bits = 268435456 (268 435 456)
# to transfer lat lon (360 degree range) 268435456/360=745654
# we could use different factors for lat lon due to the differing range, however
# this will be fine.
# 1 degree = 110574 meters;
encode : func(v)
{
return BinaryAsciiTransfer.encodeInt((v.lat()+90)*745654,5)
~ BinaryAsciiTransfer.encodeInt((v.lon()+180)*745654,5)
~ TransferInt.encode(v.alt(), 3);
},
decode : func(v,pos)
{
var dv = BinaryAsciiTransfer.decodeInt(v,5,pos);
var lat = (dv.value / 745654)-90;
dv = BinaryAsciiTransfer.decodeInt(v,5,dv.pos);
var lon = (dv.value / 745654)-180;
dv = TransferInt.decode(v, 3, dv.pos);
var alt =dv.value;
dv.value = geo.Coord.new().set_latlon(lat, lon).set_alt(alt);
return dv;
}
};
#setprop("/sim/startup/terminal-ansi-colors",0);
#for(i=-1;i<=1;i+=0.1)
#print ("i ",i, " --> ", (TransferNorm.decode(TransferNorm.encode(i,2), 2,0)).value);
#debug.dump(TransferNorm.decode(TransferNorm.encode(-1,2), 2,0));
#debug.dump(TransferNorm.decode(TransferNorm.encode(0,2), 2,0));
#debug.dump(TransferNorm.decode(TransferNorm.encode(1,2), 2,0));
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