Estoy empezando a trabajar en una herramienta de análisis dinámico para JS y me gustaría crear un perfil de todo un entorno discretamente. Básicamente atravieso varios contextos, profundizando en los objetos, y cada vez que toco una función, me engancho. Ahora bien, esto funciona relativamente bien, excepto por el hecho de que se rompe cuando se trata de las bibliotecas como jQuery/prototipo etc.Javascript perder contexto al enganchar recursivamente
Este es mi código hasta ahora (comentado a lo mejor de mi capacidad):
var __PROFILER_global_props = new Array(); // visited properties
/**
* Hook into a function
* @name the name of the function
* @fn the reference to the function
* @parent the parent object
*/
function __PROFILER_hook(name, fn, parent) {
//console.log('hooking ' + name + ' ' + fn + ' ' + parent);
if (typeof parent == 'undefined')
parent = window;
for (var i in parent) {
// find the right function
if (parent[i] === fn) {
// hook into it
console.log('--> hooking ' + name);
parent[i] = function() {
console.log('called ' + name);
return fn.apply(parent, arguments);
}
//parent[i] = fn; // <-- this works (obviously)
break;
}
}
}
/**
* Traverse object recursively, looking for functions or objects
* @obj the object we're going into
* @parent the parent (used for keeping a breadcrumb)
*/
function __PROFILER_traverse(obj, parent) {
for (i in obj) {
// get the toString object type
var oo = Object.prototype.toString.call(obj[i]);
// if we're NOT an object Object or an object Function
if (oo != '[object Object]' && oo != '[object Function]') {
console.log("...skipping " + i);
// skip
// ... the reason we do this is because Functions can have sub-functions and sub-objects (just like Objects)
continue;
}
if (__PROFILER_global_props.indexOf(i) == -1 // first we want to make sure we haven't already visited this property
&& (i != '__PROFILER_global_props' // we want to make sure we're not descending infinitely
&& i != '__PROFILER_traverse' // or recusrively hooking into our own hooking functions
&& i != '__PROFILER_hook' // ...
&& i != 'Event' // Event tends to be called a lot, so just skip it
&& i != 'log' // using FireBug for debugging, so again, avoid hooking into the logging functions
&& i != 'notifyFirebug')) { // another firebug quirk, skip this as well
// log the element we're looking at
console.log(parent+'.'+i);
// push it.. it's going to end up looking like '__PROFILER_BASE_.something.somethingElse.foo'
__PROFILER_global_props.push(parent+'.'+i);
try {
// traverse the property recursively
__PROFILER_traverse(obj[i], parent+'.'+i);
// hook into it (this function does nothing if obj[i] is not a function)
__PROFILER_hook(i, obj[i], obj);
} catch (err) {
// most likely a security exception. we don't care about this.
}
} else {
// some debugging
console.log(i + ' already visited');
}
}
}
Ese es el perfil y así es como yo invoco:
// traverse the window
__PROFILER_traverse(window, '__PROFILER_BASE_');
// testing this on jQuery.com
$("p.neat").addClass("ohmy").show("slow");
de desplazamiento funciona bien y de enganche funciona bien siempre y cuando las funciones son simples y no anónimo (creo enganchar en funciones anónimas es imposible así que no estoy demasiado preocupado por eso).
Esto es una salida recortada de la fase de preprocesamiento.
notifyFirebug already visited
...skipping firebug
...skipping userObjects
__PROFILER_BASE_.loadFirebugConsole
--> hooking loadFirebugConsole
...skipping location
__PROFILER_BASE_.$
__PROFILER_BASE_.$.fn
__PROFILER_BASE_.$.fn.init
--> hooking init
...skipping selector
...skipping jquery
...skipping length
__PROFILER_BASE_.$.fn.size
--> hooking size
__PROFILER_BASE_.$.fn.toArray
--> hooking toArray
__PROFILER_BASE_.$.fn.get
--> hooking get
__PROFILER_BASE_.$.fn.pushStack
--> hooking pushStack
__PROFILER_BASE_.$.fn.each
--> hooking each
__PROFILER_BASE_.$.fn.ready
--> hooking ready
__PROFILER_BASE_.$.fn.eq
--> hooking eq
__PROFILER_BASE_.$.fn.first
--> hooking first
__PROFILER_BASE_.$.fn.last
--> hooking last
__PROFILER_BASE_.$.fn.slice
--> hooking slice
__PROFILER_BASE_.$.fn.map
--> hooking map
__PROFILER_BASE_.$.fn.end
--> hooking end
__PROFILER_BASE_.$.fn.push
--> hooking push
__PROFILER_BASE_.$.fn.sort
--> hooking sort
__PROFILER_BASE_.$.fn.splice
--> hooking splice
__PROFILER_BASE_.$.fn.extend
--> hooking extend
__PROFILER_BASE_.$.fn.data
--> hooking data
__PROFILER_BASE_.$.fn.removeData
--> hooking removeData
__PROFILER_BASE_.$.fn.queue
Cuando ejecuto $("p.neat").addClass("ohmy").show("slow");
en jQuery.com (a través de Firebug), me sale una pila de llamadas apropiada, pero parecen perder mi contexto en algún lugar a lo largo del camino porque no pasa nada y me da un error e is undefined
de jQuery (claramente, el enganche arruinó algo).
called init
called init
called find
called find
called pushStack
called pushStack
called init
called init
called isArray
called isArray
called merge
called merge
called addClass
called addClass
called isFunction
called isFunction
called show
called show
called each
called each
called isFunction
called isFunction
called animate
called animate
called speed
called speed
called isFunction
called isFunction
called isEmptyObject
called isEmptyObject
called queue
called queue
called each
called each
called each
called each
called isFunction
called isFunction
El problema es que creo que estoy perdiendo el contexto this
al llamar
return fn.apply(parent, arguments);
Aquí hay otro interesante peculiaridad. Si engancho antes transversal, es decir:
// hook into it (this function does nothing if obj[i] is not a function)
__PROFILER_hook(i, obj[i], obj);
// traverse the property recursively
__PROFILER_traverse(obj[i], parent+'.'+i);
.. la aplicación se ejecuta absolutamente bien, pero se altera la pila de llamadas (y no parecen tener funciones específicas jQuery) por alguna razón:
called $
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called setInterval
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called getComputedStyle
called clearInterval
.. en lugar de animation
, show
, merge
, etc. en este momento, todo el gancho no es decir called functionName
pero al final me gustaría hacer seguimientos de pila y funciones de tiempo (a través de un applet de Java).
Esta pregunta terminó siendo enorme y me disculpo, pero cualquier ayuda es apreciada.
Nota: el código anterior puede bloquear su navegador si no tiene cuidado. Advertencia justa: P
Pregunta similar: http://stackoverflow.com/questions/5033836/adding-console-log-to-every-function-automatically –