wire.js
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"use strict";
/*
Copyright (C) 2012 by Jeremy P. White <jwhite@codeweavers.com>
This file is part of spice-html5.
spice-html5 is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
spice-html5 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with spice-html5. If not, see <http://www.gnu.org/licenses/>.
*/
/*--------------------------------------------------------------------------------------
** SpiceWireReader
** This class will receive messages from a WebSocket and relay it to a given
** callback. It will optionally save and pass along a header, useful in processing
** the mini message format.
**--------------------------------------------------------------------------------------*/
function SpiceWireReader(sc, callback)
{
this.sc = sc;
this.callback = callback;
this.needed = 0;
this.buffers = [];
this.sc.ws.wire_reader = this;
this.sc.ws.binaryType = "arraybuffer";
this.sc.ws.addEventListener('message', wire_blob_catcher);
}
SpiceWireReader.prototype =
{
/*------------------------------------------------------------------------
** Process messages coming in from our WebSocket
**----------------------------------------------------------------------*/
inbound: function (mb)
{
var at;
/* Just buffer if we don't need anything yet */
if (this.needed == 0)
{
this.buffers.push(mb);
return;
}
/* Optimization - if we have just one inbound block, and it's
suitable for our needs, just use it. */
if (this.buffers.length == 0 && mb.byteLength >= this.needed)
{
if (mb.byteLength > this.needed)
{
this.buffers.push(mb.slice(this.needed));
mb = mb.slice(0, this.needed);
}
this.callback.call(this.sc, mb,
this.saved_msg_header || undefined);
}
else
{
this.buffers.push(mb);
}
/* If we have fragments that add up to what we need, combine them */
/* FIXME - it would be faster to revise the processing code to handle
** multiple fragments directly. Essentially, we should be
** able to do this without any slice() or combine_array_buffers() calls */
while (this.buffers.length > 1 && this.buffers[0].byteLength < this.needed)
{
var mb1 = this.buffers.shift();
var mb2 = this.buffers.shift();
this.buffers.unshift(combine_array_buffers(mb1, mb2));
}
while (this.buffers.length > 0 && this.buffers[0].byteLength >= this.needed)
{
mb = this.buffers.shift();
if (mb.byteLength > this.needed)
{
this.buffers.unshift(mb.slice(this.needed));
mb = mb.slice(0, this.needed);
}
this.callback.call(this.sc, mb,
this.saved_msg_header || undefined);
}
},
request: function(n)
{
this.needed = n;
},
save_header: function(h)
{
this.saved_msg_header = h;
},
clear_header: function()
{
this.saved_msg_header = undefined;
},
}
function wire_blob_catcher(e)
{
DEBUG > 1 && console.log(">> WebSockets.onmessage");
DEBUG > 1 && console.log("id " + this.wire_reader.sc.connection_id +"; type " + this.wire_reader.sc.type);
SpiceWireReader.prototype.inbound.call(this.wire_reader, e.data);
}