mmir-lib
Version:
MMIR (Mobile Multimodal Interaction and Relay) library
200 lines (172 loc) • 4.7 kB
JavaScript
define(['mmirf/jisonGen','mmirf/asyncGen','mmirf/util/deferred','mmirf/util/extend'],
/**
* Asynchronous generator for executable language-grammars (i.e. converted JSON grammars).
*
* <p>
* This generator uses Jison for compiling the JSON grammar.
*
* <p>
* Usage of this compile is the same as for synchronously working JisonGenerator.
*
* @see JisonGenerator
*
* @class
* @constant
* @public
* @name JisonAsyncGenerator
* @memberOf mmir.env.grammar
* @hideconstructor
*
* @requires JisonGenerator
*/
function(jisonGen, asyncGen, deferred, extend){
/**
* Counter for generating IDs for compile-jobs that
* are sent to the WebWorker
*
* @private
* @memberOf JisonAsyncGenerator#
*/
var _taskId = 1;
/**
* WebWorker instance for compiling parser asynchronously
*
* @private
* @memberOf JisonAsyncGenerator#
*/
var asyncCompiler;
/**
* printError function reference for compile-errors
*
* @private
* @memberOf JisonAsyncGenerator#
*/
var printError = jisonGen.printError;
/**
* create & initialize the async compiler:
*
* creates the asyncCompiler and initDef,
* and sends init-message to asyncCompiler.
*
* @private
* @memberOf JisonAsyncGenerator#
*/
function initAsyncCompiler(){
asyncCompiler = asyncGen.createWorker(jisonGen.engineId);
initDef = deferred();
var initMsg = asyncCompiler.prepareOnInit(jisonGen, initDef);
asyncCompiler.postMessage(initMsg);
asyncCompiler._onerror = printError;
}
////////////////////init async compiler/thread /////////////////////////
//for async init-signaling:
var initDef;
//immedately start initialization for async compiler:
initAsyncCompiler();
/**
* Exported (public) functions for the jison grammar-engine.
* @public
* @type GrammarGenerator
* @memberOf JisonAsyncGenerator#
*/
var jisonAsyncGen = {
/** @scope JisonAsyncGenerator.prototype */
/**
* @see JisonAsyncGenerator#init
* @memberOf JisonAsyncGenerator.prototype
*/
init: function(callback){
if(!asyncCompiler){
//in case the compiler was destroyed -> re-init:
initAsyncCompiler();
}
//overwrite with own async "init signal"
if(callback){
initDef.then(callback, callback);
}
return initDef;
},
/**
* frees up the resources of the async compiler
* ({@link #init} will re-initialize the resources)
*
* @param {Boolean} [force] OPTIONAL
* if TRUE, immediately terminates the async worker, otherwise
* will wait until no pending queries are registered any more
*
* @see CompileWebWorker#hasPendingCallback
* @see CompileWebWorker#addCallback
*
* @memberOf JisonAsyncGenerator.prototype
*/
destroy: function(force){
if(asyncCompiler && asyncCompiler.terminate){
if(!force){
if(asyncCompiler.hasPendingCallback()){
var tis = this;
asyncCompiler._onidle = function(){
tis.destroy();
}
return;
}
}
asyncCompiler.terminate();
asyncCompiler = null;
}
},
/**
* @returns {Boolean} if this engine compilation works asynchronously.
* The current implementation works asynchronously (returns TRUE)
*
* @memberOf JisonAsyncGenerator.prototype
*/
isAsyncCompilation: function(){ return true; },
/**
* @see JisonGenerator#_compileParser
* @protected
*/
_compileParser: function(grammarDefinition, options, onAfterCompileParserResult){
//start compilation in web-worker:
asyncCompiler.postMessage({
cmd: 'parse',
id: onAfterCompileParserResult,
config: options,
text: grammarDefinition
});
},
// /**
// * @see JisonGenerator#_preparePrintError
// * @protected
// */
// _preparePrintError: function(){},//<- overwrite with NOOP
/**
* @see JisonGenerator#_afterCompileParser
* @protected
*/
_afterCompileParser: function(compileParserModuleFunc){
//callback-ID:
var taskId = '' + _taskId++;
//register callback for messages from web-worker:
asyncCompiler.addCallback(taskId, function(evtData){
if(evtData.error){
//handle error message:
if(printError){
printError(evtData.error);
}
else {
console.error(evtData.error);
}
//////////////////// EARLY EXIT /////////////////
//NOTE this is not the final message from the compiler-thread...
return;
}
var hasError = evtData.isError;
var grammarParser = evtData.def;
compileParserModuleFunc(grammarParser, hasError);
});
return taskId;
}
};
//extend/overload sync-compiler with async-compiler:
return extend({}, jisonGen, jisonAsyncGen);
});