gir.js

/**
 *  Example use of this module:
 *    var gir = require('./path/to/gir.js')
 *     ,  gtk = gir.load('Gtk', '3.0');
 **/

//import gir library and EventEmitter
//var gir = module.exports = require('./build/Release/lib.target/girepository.node'),
//    EventEmitter = require('events').EventEmitter;
var gir = module.exports = require('./build/Release/girepository'),
    EventEmitter = require('events').EventEmitter;

/******************************************************************************/

/* BEGIN HELPERS */

/**
 * Adopted from jquery's extend method. Under the terms of MIT License.
 *
 * http://code.jquery.com/jquery-1.4.2.js
 *
 * Modified by Brian White to use Array.isArray instead of the custom isArray
 * method.
 */
function extend() {
  // copy reference to target object
  var target = arguments[0] || {},
      i = 1,
      length = arguments.length,
      deep = false,
      options,
      name,
      src,
      copy;

  // Handle a deep copy situation
  if (typeof target === "boolean") {
    deep = target;
    target = arguments[1] || {};
    // skip the boolean and the target
    i = 2;
  }

  // Handle case when target is a string or something (possible in deep copy)
  if (typeof target !== "object" && !typeof target === 'function')
    target = {};

  var isPlainObject = function(obj) {
    // Must be an Object.
    // Because of IE, we also have to check the presence of the constructor
    // property.
    // Make sure that DOM nodes and window objects don't pass through, as well
    if (!obj || toString.call(obj) !== "[object Object]" || obj.nodeType
        || obj.setInterval)
      return false;
    
    var has_own_constructor = hasOwnProperty.call(obj, "constructor");
    var has_is_prop_of_method = hasOwnProperty.call(obj.constructor.prototype,
                                                    "isPrototypeOf");
    // Not own constructor property must be Object
    if (obj.constructor && !has_own_constructor && !has_is_prop_of_method)
      return false;
    
    // Own properties are enumerated firstly, so to speed up,
    // if last one is own, then all properties are own.

    var last_key;
    for (key in obj)
      last_key = key;
    
    return typeof last_key === "undefined" || hasOwnProperty.call(obj, last_key);
  };


  for (; i < length; i++) {
    // Only deal with non-null/undefined values
    if ((options = arguments[i]) !== null) {
      // Extend the base object
      for (name in options) {
        src = target[name];
        copy = options[name];

        // Prevent never-ending loop
        if (target === copy)
            continue;

        // Recurse if we're merging object literal values or arrays
        if (deep && copy && (isPlainObject(copy) || Array.isArray(copy))) {
          var clone = src && (isPlainObject(src) || Array.isArray(src)
                              ? src : (Array.isArray(copy) ? [] : {}));

          // Never move original objects, clone them
          target[name] = extend(deep, clone, copy);

        // Don't bring in undefined values
        } else if (typeof copy !== "undefined")
          target[name] = copy;
      }
    }
  }

  // Return the modified object
  return target;
};

/**
 * Copied from jQuery. Under the terms of MIT or GPLv2 License.
 * http://code.jquery.com/jquery-1.7.1.js
 */
function merge(first, second) {
		var i = first.length,
			j = 0;

		if ( typeof second.length === "number" ) {
			for ( var l = second.length; j < l; j++ ) {
				first[ i++ ] = second[ j ];
			}

		} else {
			while ( second[j] !== undefined ) {
				first[ i++ ] = second[ j++ ];
			}
		}

		first.length = i;

		return first;
	}
	
/**
 * Copied from jQuery. Under the terms of MIT or GPLv2 License.
 * http://code.jquery.com/jquery-1.7.1.js
 *
 * Modified by David Ball to work outside the jQuery environment. Removed
 * reference to jQuery.isWindow() and jQuery.type(). Modified jQuery.merge() to
 * use local scope. Applied logic from jQuery.type() since there is no DOM.
 * Changed push to Array.prototype.push.
 */
function makeArray(array, results) {
  var ret = results || [];

  if ( array != null ) {
	  // The window, strings (and functions) also have 'length'
	  // Tweaked logic slightly to handle Blackberry 4.7 RegExp issues #6930
	  var type = array == null ? String( obj ) : "object";

	  if ( array.length == null || type === "string" || type === "function" || type === "regexp") {
		  Array.prototype.push.call( ret, array );
	  } else {
		  merge( ret, array );
	  }
  }

  return ret;
} 

/* END HELPERS */

/******************************************************************************/

/* BEGIN LOGIC */

//save default module routines
gir._gir_baseInit = gir.init;
gir._gir_baseLoad = gir.load;

//add init flag property
gir._gir_hasInit = false;

//override default init
gir.init = function() {
  //don't init twice, seems useless to do so
  if (!this._gir_hasInit) {
    this._gir_hasInit = true;
    return gir['_gir_baseInit'].apply(this, Array.prototype.slice.call(arguments));
  }
};

//create callable method object
function CallableMethod(methodName) {
  //the internal function does all the hard work
  var invocation = function() {
    var args = Array.prototype.slice.call(arguments);
    if (args == undefined) args = new Array();
    for (var i = args.length; i > 0; i--)
      args[i] = args[i-1];
    args[0] = methodName;
    //call the method on the gir provided object
    this.apply(this, args);
  };
  return invocation;
}

//override default loader
gir.load = function() {
  //auto-init if needed
  if (!this._gir_hasInit) this.init();
  
  //load gir module
  var obj = gir['_gir_baseLoad'].apply(this, Array.prototype.slice.call(arguments));
  
  //check for error
  if (!obj) return obj;
  
  //TODO: consider storing loaded module gir somewhere now so that it can be unloaded later ?
  
  //for each object within the loaded gir module:
  //  task 1. figure out which loaded objects can trigger events, and add EventEmitter as needed
  //  task 2. make method names callable methods
  for (var subobj in obj) {
    //task 1: add EventEmitter as needed
    //determine whether eventable
    var eventable = obj[subobj].__signals__ != undefined
                      && makeArray(obj[subobj].__signals__).length>0;
    if (eventable) {
      //combine EventEmitter logic with eventable gir objects
      extend(true, obj[subobj].prototype, EventEmitter.prototype);
      //check for prop __watch_signal__, if found, override EventEmitter.on()
      if (obj[subobj].prototype['__watch_signal__'] != undefined) {
        obj[subobj].prototype._baseEventEmitter_on = obj[subobj].prototype.on;
        obj[subobj].prototype.on = function () {
          //tell gir loaded object to listen for the signal
          this.__watch_signal__(arguments[0]);
          //dispatch normally
          this._baseEventEmitter_on(arguments[0], arguments[1]);
        };
      }
    }

    //task 2: expose object methods to objects and make them callable
    for (var prop in obj[subobj]) {
      switch (prop) {
        case '__methods__':
          for (var method_offset in obj[subobj][prop]) {
            var method_name = obj[subobj][prop][method_offset];
            //debug:console.log(subobj + '.'  + method_name + '() discovered');
            //add method handler to object if possible
            if (obj[subobj].prototype[method_name] != undefined)
              {}//debug:console.warn("[node-gir] " + subobj + " object provides it's own " + method_name + " method. Not replacing existing method. :-(");
            else
              obj[subobj].prototype[method_name] = CallableMethod(method_name);
          }
          break;
      }
    }
    //console.log(subobj, obj[subobj]);
  }

  //keep the loader in the loaded object in case caller wants to reuse the loader
  if (obj.gir != undefined)
    console.warn("[node-gir] Object provides it's own gir. Not replacing gir. Strange error? :-(");
  else
    obj.gir = this;

  //return the brutally overridden object
  return obj;
};

/* END LOGIC */