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[mediawiki.git] / resources / lib / oojs / oojs.js

/*!
 * OOjs v1.0.9
 * https://www.mediawiki.org/wiki/OOjs
 *
 * Copyright 2011-2014 OOjs Team and other contributors.
 * Released under the MIT license
 * http://oojs.mit-license.org
 *
 * Date: Wed Apr 02 2014 14:20:50 GMT-0700 (PDT)
 */
( function ( global ) {

'use strict';
var
        /**
         * Namespace for all classes, static methods and static properties.
         * @class OO
         * @singleton
         */
        oo = {},
        hasOwn = oo.hasOwnProperty,
        toString = oo.toString;

/* Class Methods */

/**
 * Assert whether a value is a plain object or not.
 *
 * @param {Mixed} obj
 * @return {boolean}
 */
oo.isPlainObject = function ( obj ) {
        // Any object or value whose internal [[Class]] property is not "[object Object]"
        if ( toString.call( obj ) !== '[object Object]' ) {
                return false;
        }

        // The try/catch suppresses exceptions thrown when attempting to access
        // the "constructor" property of certain host objects suich as window.location
        // in Firefox < 20 (https://bugzilla.mozilla.org/814622)
        try {
                if ( obj.constructor &&
                                !hasOwn.call( obj.constructor.prototype, 'isPrototypeOf' ) ) {
                        return false;
                }
        } catch ( e ) {
                return false;
        }

        return true;
};

/**
 * Utility to initialize a class for OO inheritance.
 *
 * Currently this just initializes an empty static object.
 *
 * @param {Function} fn
 */
oo.initClass = function ( fn ) {
        fn.static = fn.static || {};
};

/**
 * Utility for common usage of Object#create for inheriting from one
 * prototype to another.
 *
 * Beware: This redefines the prototype, call before setting your prototypes.
 * Beware: This redefines the prototype, can only be called once on a function.
 *  If called multiple times on the same function, the previous prototype is lost.
 *  This is how prototypal inheritance works, it can only be one straight chain
 *  (just like classical inheritance in PHP for example). If you need to work with
 *  multiple constructors consider storing an instance of the other constructor in a
 *  property instead, or perhaps use a mixin (see OO.mixinClass).
 *
 *     function Thing() {}
 *     Thing.prototype.exists = function () {};
 *
 *     function Person() {
 *         Person.super.apply( this, arguments );
 *     }
 *     OO.inheritClass( Person, Thing );
 *     Person.static.defaultEyeCount = 2;
 *     Person.prototype.walk = function () {};
 *
 *     function Jumper() {
 *         Jumper.super.apply( this, arguments );
 *     }
 *     OO.inheritClass( Jumper, Person );
 *     Jumper.prototype.jump = function () {};
 *
 *     Jumper.static.defaultEyeCount === 2;
 *     var x = new Jumper();
 *     x.jump();
 *     x.walk();
 *     x instanceof Thing && x instanceof Person && x instanceof Jumper;
 *
 * @param {Function} targetFn
 * @param {Function} originFn
 * @throws {Error} If target already inherits from origin
 */
oo.inheritClass = function ( targetFn, originFn ) {
        if ( targetFn.prototype instanceof originFn ) {
                throw new Error( 'Target already inherits from origin' );
        }

        var targetConstructor = targetFn.prototype.constructor;

        targetFn.super = originFn;
        targetFn.prototype = Object.create( originFn.prototype, {
                // Restore constructor property of targetFn
                constructor: {
                        value: targetConstructor,
                        enumerable: false,
                        writable: true,
                        configurable: true
                }
        } );

        // Extend static properties - always initialize both sides
        oo.initClass( originFn );
        targetFn.static = Object.create( originFn.static );
};

/**
 * Utility to copy over *own* prototype properties of a mixin.
 * The 'constructor' (whether implicit or explicit) is not copied over.
 *
 * This does not create inheritance to the origin. If inheritance is needed
 * use oo.inheritClass instead.
 *
 * Beware: This can redefine a prototype property, call before setting your prototypes.
 * Beware: Don't call before oo.inheritClass.
 *
 *     function Foo() {}
 *     function Context() {}
 *
 *     // Avoid repeating this code
 *     function ContextLazyLoad() {}
 *     ContextLazyLoad.prototype.getContext = function () {
 *         if ( !this.context ) {
 *             this.context = new Context();
 *         }
 *         return this.context;
 *     };
 *
 *     function FooBar() {}
 *     OO.inheritClass( FooBar, Foo );
 *     OO.mixinClass( FooBar, ContextLazyLoad );
 *
 * @param {Function} targetFn
 * @param {Function} originFn
 */
oo.mixinClass = function ( targetFn, originFn ) {
        var key;

        // Copy prototype properties
        for ( key in originFn.prototype ) {
                if ( key !== 'constructor' && hasOwn.call( originFn.prototype, key ) ) {
                        targetFn.prototype[key] = originFn.prototype[key];
                }
        }

        // Copy static properties - always initialize both sides
        oo.initClass( targetFn );
        if ( originFn.static ) {
                for ( key in originFn.static ) {
                        if ( hasOwn.call( originFn.static, key ) ) {
                                targetFn.static[key] = originFn.static[key];
                        }
                }
        } else {
                oo.initClass( originFn );
        }
};

/* Object Methods */

/**
 * Create a new object that is an instance of the same
 * constructor as the input, inherits from the same object
 * and contains the same own properties.
 *
 * This makes a shallow non-recursive copy of own properties.
 * To create a recursive copy of plain objects, use #copy.
 *
 *     var foo = new Person( mom, dad );
 *     foo.setAge( 21 );
 *     var foo2 = OO.cloneObject( foo );
 *     foo.setAge( 22 );
 *
 *     // Then
 *     foo2 !== foo; // true
 *     foo2 instanceof Person; // true
 *     foo2.getAge(); // 21
 *     foo.getAge(); // 22
 *
 * @param {Object} origin
 * @return {Object} Clone of origin
 */
oo.cloneObject = function ( origin ) {
        var key, r;

        r = Object.create( origin.constructor.prototype );

        for ( key in origin ) {
                if ( hasOwn.call( origin, key ) ) {
                        r[key] = origin[key];
                }
        }

        return r;
};

/**
 * Get an array of all property values in an object.
 *
 * @param {Object} Object to get values from
 * @return {Array} List of object values
 */
oo.getObjectValues = function ( obj ) {
        var key, values;

        if ( obj !== Object( obj ) ) {
                throw new TypeError( 'Called on non-object' );
        }

        values = [];
        for ( key in obj ) {
                if ( hasOwn.call( obj, key ) ) {
                        values[values.length] = obj[key];
                }
        }

        return values;
};

/**
 * Recursively compares properties between two objects.
 *
 * A false result may be caused by property inequality or by properties in one object missing from
 * the other. An asymmetrical test may also be performed, which checks only that properties in the
 * first object are present in the second object, but not the inverse.
 *
 * @param {Object} a First object to compare
 * @param {Object} b Second object to compare
 * @param {boolean} [asymmetrical] Whether to check only that b contains values from a
 * @return {boolean} If the objects contain the same values as each other
 */
oo.compare = function ( a, b, asymmetrical ) {
        var aValue, bValue, aType, bType, k;

        if ( a === b ) {
                return true;
        }

        for ( k in a ) {
                aValue = a[k];
                bValue = b[k];
                aType = typeof aValue;
                bType = typeof bValue;
                if ( aType !== bType ||
                        ( ( aType === 'string' || aType === 'number' ) && aValue !== bValue ) ||
                        ( aValue === Object( aValue ) && !oo.compare( aValue, bValue, asymmetrical ) ) ) {
                        return false;
                }
        }
        // If the check is not asymmetrical, recursing with the arguments swapped will verify our result
        return asymmetrical ? true : oo.compare( b, a, true );
};

/**
 * Create a plain deep copy of any kind of object.
 *
 * Copies are deep, and will either be an object or an array depending on `source`.
 *
 * @param {Object} source Object to copy
 * @param {Function} [callback] Applied to leaf values before they added to the clone
 * @return {Object} Copy of source object
 */
oo.copy = function ( source, callback ) {
        var key, sourceValue, sourceType, destination;

        if ( typeof source.clone === 'function' ) {
                return source.clone();
        }

        destination = Array.isArray( source ) ? new Array( source.length ) : {};

        for ( key in source ) {
                sourceValue = source[key];
                sourceType = typeof sourceValue;
                if ( Array.isArray( sourceValue ) ) {
                        // Array
                        destination[key] = oo.copy( sourceValue, callback );
                } else if ( sourceValue && typeof sourceValue.clone === 'function' ) {
                        // Duck type object with custom clone method
                        destination[key] = callback ?
                                callback( sourceValue.clone() ) : sourceValue.clone();
                } else if ( sourceValue && typeof sourceValue.cloneNode === 'function' ) {
                        // DOM Node
                        destination[key] = callback ?
                                callback( sourceValue.cloneNode( true ) ) : sourceValue.cloneNode( true );
                } else if ( oo.isPlainObject( sourceValue ) ) {
                        // Plain objects
                        destination[key] = oo.copy( sourceValue, callback );
                } else {
                        // Non-plain objects (incl. functions) and primitive values
                        destination[key] = callback ? callback( sourceValue ) : sourceValue;
                }
        }

        return destination;
};

/**
 * Generate a hash of an object based on its name and data.
 *
 * Performance optimization: <http://jsperf.com/ve-gethash-201208#/toJson_fnReplacerIfAoForElse>
 *
 * To avoid two objects with the same values generating different hashes, we utilize the replacer
 * argument of JSON.stringify and sort the object by key as it's being serialized. This may or may
 * not be the fastest way to do this; we should investigate this further.
 *
 * Objects and arrays are hashed recursively. When hashing an object that has a .getHash()
 * function, we call that function and use its return value rather than hashing the object
 * ourselves. This allows classes to define custom hashing.
 *
 * @param {Object} val Object to generate hash for
 * @return {string} Hash of object
 */
oo.getHash = function ( val ) {
        return JSON.stringify( val, oo.getHash.keySortReplacer );
};

/**
 * Helper function for OO.getHash which sorts objects by key.
 *
 * This is a callback passed into JSON.stringify.
 *
 * @method getHash_keySortReplacer
 * @param {string} key Property name of value being replaced
 * @param {Mixed} val Property value to replace
 * @return {Mixed} Replacement value
 */
oo.getHash.keySortReplacer = function ( key, val ) {
        var normalized, keys, i, len;
        if ( val && typeof val.getHashObject === 'function' ) {
                // This object has its own custom hash function, use it
                val = val.getHashObject();
        }
        if ( !Array.isArray( val ) && Object( val ) === val ) {
                // Only normalize objects when the key-order is ambiguous
                // (e.g. any object not an array).
                normalized = {};
                keys = Object.keys( val ).sort();
                i = 0;
                len = keys.length;
                for ( ; i < len; i += 1 ) {
                        normalized[keys[i]] = val[keys[i]];
                }
                return normalized;

        // Primitive values and arrays get stable hashes
        // by default. Lets those be stringified as-is.
        } else {
                return val;
        }
};

/**
 * Compute the union (duplicate-free merge) of a set of arrays.
 *
 * Arrays values must be convertable to object keys (strings).
 *
 * By building an object (with the values for keys) in parallel with
 * the array, a new item's existence in the union can be computed faster.
 *
 * @param {Array...} arrays Arrays to union
 * @return {Array} Union of the arrays
 */
oo.simpleArrayUnion = function () {
        var i, ilen, arr, j, jlen,
                obj = {},
                result = [];

        for ( i = 0, ilen = arguments.length; i < ilen; i++ ) {
                arr = arguments[i];
                for ( j = 0, jlen = arr.length; j < jlen; j++ ) {
                        if ( !obj[ arr[j] ] ) {
                                obj[ arr[j] ] = true;
                                result.push( arr[j] );
                        }
                }
        }

        return result;
};

/**
 * Combine arrays (intersection or difference).
 *
 * An intersection checks the item exists in 'b' while difference checks it doesn't.
 *
 * Arrays values must be convertable to object keys (strings).
 *
 * By building an object (with the values for keys) of 'b' we can
 * compute the result faster.
 *
 * @private
 * @param {Array} a First array
 * @param {Array} b Second array
 * @param {boolean} includeB Whether to items in 'b'
 * @return {Array} Combination (intersection or difference) of arrays
 */
function simpleArrayCombine( a, b, includeB ) {
        var i, ilen, isInB,
                bObj = {},
                result = [];

        for ( i = 0, ilen = b.length; i < ilen; i++ ) {
                bObj[ b[i] ] = true;
        }

        for ( i = 0, ilen = a.length; i < ilen; i++ ) {
                isInB = !!bObj[ a[i] ];
                if ( isInB === includeB ) {
                        result.push( a[i] );
                }
        }

        return result;
}

/**
 * Compute the intersection of two arrays (items in both arrays).
 *
 * Arrays values must be convertable to object keys (strings).
 *
 * @param {Array} a First array
 * @param {Array} b Second array
 * @return {Array} Intersection of arrays
 */
oo.simpleArrayIntersection = function ( a, b ) {
        return simpleArrayCombine( a, b, true );
};

/**
 * Compute the difference of two arrays (items in 'a' but not 'b').
 *
 * Arrays values must be convertable to object keys (strings).
 *
 * @param {Array} a First array
 * @param {Array} b Second array
 * @return {Array} Intersection of arrays
 */
oo.simpleArrayDifference = function ( a, b ) {
        return simpleArrayCombine( a, b, false );
};
/**
 * @class OO.EventEmitter
 *
 * @constructor
 */
oo.EventEmitter = function OoEventEmitter() {
        // Properties

        /**
         * Storage of bound event handlers by event name.
         *
         * @property
         */
        this.bindings = {};
};

/* Methods */

/**
 * Add a listener to events of a specific event.
 *
 * If the callback/context are already bound to the event, they will not be bound again.
 *
 * @param {string} event Type of event to listen to
 * @param {Function} callback Function to call when event occurs
 * @param {Array} [args] Arguments to pass to listener, will be prepended to emitted arguments
 * @param {Object} [context=null] Object to use as context for callback function or call method on
 * @throws {Error} Listener argument is not a function or method name
 * @chainable
 */
oo.EventEmitter.prototype.on = function ( event, callback, args, context ) {
        var i, bindings, binding;

        // Validate callback
        if ( typeof callback !== 'function' ) {
                throw new Error( 'Invalid callback. Function or method name expected.' );
        }
        // Fallback to null context
        if ( arguments.length < 4 ) {
                context = null;
        }
        if ( this.bindings.hasOwnProperty( event ) ) {
                // Check for duplicate callback and context for this event
                bindings = this.bindings[event];
                i = bindings.length;
                while ( i-- ) {
                        binding = bindings[i];
                        if ( bindings.callback === callback && bindings.context === context ) {
                                return this;
                        }
                }
        } else {
                // Auto-initialize bindings list
                bindings = this.bindings[event] = [];
        }
        // Add binding
        bindings.push( {
                callback: callback,
                args: args,
                context: context
        } );
        return this;
};

/**
 * Adds a one-time listener to a specific event.
 *
 * @param {string} event Type of event to listen to
 * @param {Function} listener Listener to call when event occurs
 * @chainable
 */
oo.EventEmitter.prototype.once = function ( event, listener ) {
        var eventEmitter = this;
        return this.on( event, function listenerWrapper() {
                eventEmitter.off( event, listenerWrapper );
                listener.apply( eventEmitter, Array.prototype.slice.call( arguments, 0 ) );
        } );
};

/**
 * Remove a specific listener from a specific event.
 *
 * @param {string} event Type of event to remove listener from
 * @param {Function} [callback] Listener to remove, omit to remove all
 * @param {Object} [context=null] Object used context for callback function or method
 * @chainable
 * @throws {Error} Listener argument is not a function
 */
oo.EventEmitter.prototype.off = function ( event, callback, context ) {
        var i, bindings;

        if ( arguments.length === 1 ) {
                // Remove all bindings for event
                if ( event in this.bindings ) {
                        delete this.bindings[event];
                }
        } else {
                if ( typeof callback !== 'function' ) {
                        throw new Error( 'Invalid callback. Function expected.' );
                }
                if ( !( event in this.bindings ) || !this.bindings[event].length ) {
                        // No matching bindings
                        return this;
                }
                // Fallback to null context
                if ( arguments.length < 3 ) {
                        context = null;
                }
                // Remove matching handlers
                bindings = this.bindings[event];
                i = bindings.length;
                while ( i-- ) {
                        if ( bindings[i].callback === callback && bindings[i].context === context ) {
                                bindings.splice( i, 1 );
                        }
                }
                // Cleanup if now empty
                if ( bindings.length === 0 ) {
                        delete this.bindings[event];
                }
        }
        return this;
};

/**
 * Emit an event.
 *
 * TODO: Should this be chainable? What is the usefulness of the boolean
 * return value here?
 *
 * @param {string} event Type of event
 * @param {Mixed} args First in a list of variadic arguments passed to event handler (optional)
 * @return {boolean} If event was handled by at least one listener
 */
oo.EventEmitter.prototype.emit = function ( event ) {
        var i, len, binding, bindings, args;

        if ( event in this.bindings ) {
                // Slicing ensures that we don't get tripped up by event handlers that add/remove bindings
                bindings = this.bindings[event].slice();
                args = Array.prototype.slice.call( arguments, 1 );
                for ( i = 0, len = bindings.length; i < len; i++ ) {
                        binding = bindings[i];
                        binding.callback.apply(
                                binding.context,
                                binding.args ? binding.args.concat( args ) : args
                        );
                }
                return true;
        }
        return false;
};

/**
 * Connect event handlers to an object.
 *
 * @param {Object} context Object to call methods on when events occur
 * @param {Object.<string,string>|Object.<string,Function>|Object.<string,Array>} methods List of
 *  event bindings keyed by event name containing either method names, functions or arrays containing
 *  method name or function followed by a list of arguments to be passed to callback before emitted
 *  arguments
 * @chainable
 */
oo.EventEmitter.prototype.connect = function ( context, methods ) {
        var method, callback, args, event;

        for ( event in methods ) {
                method = methods[event];
                // Allow providing additional args
                if ( Array.isArray( method ) ) {
                        args = method.slice( 1 );
                        method = method[0];
                } else {
                        args = [];
                }
                // Allow callback to be a method name
                if ( typeof method === 'string' ) {
                        // Validate method
                        if ( !context[method] || typeof context[method] !== 'function' ) {
                                throw new Error( 'Method not found: ' + method );
                        }
                        // Resolve to function
                        callback = context[method];
                } else {
                        callback = method;
                }
                // Add binding
                this.on.apply( this, [ event, callback, args, context ] );
        }
        return this;
};

/**
 * Disconnect event handlers from an object.
 *
 * @param {Object} context Object to disconnect methods from
 * @param {Object.<string,string>|Object.<string,Function>|Object.<string,Array>} [methods] List of
 * event bindings keyed by event name containing either method names or functions
 * @chainable
 */
oo.EventEmitter.prototype.disconnect = function ( context, methods ) {
        var i, method, callback, event, bindings;

        if ( methods ) {
                // Remove specific connections to the context
                for ( event in methods ) {
                        method = methods[event];
                        if ( typeof method === 'string' ) {
                                // Validate method
                                if ( !context[method] || typeof context[method] !== 'function' ) {
                                        throw new Error( 'Method not found: ' + method );
                                }
                                // Resolve to function
                                callback = context[method];
                        } else {
                                callback = method;
                        }
                        this.off( event, callback, context );
                }
        } else {
                // Remove all connections to the context
                for ( event in this.bindings ) {
                        bindings = this.bindings[event];
                        i = bindings.length;
                        while ( i-- ) {
                                if ( bindings[i].context === context ) {
                                        this.off( event, bindings[i].callback, context );
                                }
                        }
                }
        }

        return this;
};
/**
 * @class OO.Registry
 * @mixins OO.EventEmitter
 *
 * @constructor
 */
oo.Registry = function OoRegistry() {
        // Mixin constructors
        oo.EventEmitter.call( this );

        // Properties
        this.registry = {};
};

/* Inheritance */

oo.mixinClass( oo.Registry, oo.EventEmitter );

/* Events */

/**
 * @event register
 * @param {string} name
 * @param {Mixed} data
 */

/* Methods */

/**
 * Associate one or more symbolic names with some data.
 *
 * Only the base name will be registered, overriding any existing entry with the same base name.
 *
 * @param {string|string[]} name Symbolic name or list of symbolic names
 * @param {Mixed} data Data to associate with symbolic name
 * @fires register
 * @throws {Error} Name argument must be a string or array
 */
oo.Registry.prototype.register = function ( name, data ) {
        var i, len;
        if ( typeof name === 'string' ) {
                this.registry[name] = data;
                this.emit( 'register', name, data );
        } else if ( Array.isArray( name ) ) {
                for ( i = 0, len = name.length; i < len; i++ ) {
                        this.register( name[i], data );
                }
        } else {
                throw new Error( 'Name must be a string or array, cannot be a ' + typeof name );
        }
};

/**
 * Get data for a given symbolic name.
 *
 * Lookups are done using the base name.
 *
 * @param {string} name Symbolic name
 * @return {Mixed|undefined} Data associated with symbolic name
 */
oo.Registry.prototype.lookup = function ( name ) {
        return this.registry[name];
};
/**
 * @class OO.Factory
 * @extends OO.Registry
 *
 * @constructor
 */
oo.Factory = function OoFactory() {
        oo.Factory.super.call( this );

        // Properties
        this.entries = [];
};

/* Inheritance */

oo.inheritClass( oo.Factory, oo.Registry );

/* Methods */

/**
 * Register a constructor with the factory.
 *
 * Classes must have a static `name` property to be registered.
 *
 *     function MyClass() {};
 *     OO.initClass( MyClass );
 *     // Adds a static property to the class defining a symbolic name
 *     MyClass.static.name = 'mine';
 *     // Registers class with factory, available via symbolic name 'mine'
 *     factory.register( MyClass );
 *
 * @param {Function} constructor Constructor to use when creating object
 * @throws {Error} Name must be a string and must not be empty
 * @throws {Error} Constructor must be a function
 */
oo.Factory.prototype.register = function ( constructor ) {
        var name;

        if ( typeof constructor !== 'function' ) {
                throw new Error( 'constructor must be a function, cannot be a ' + typeof constructor );
        }
        name = constructor.static && constructor.static.name;
        if ( typeof name !== 'string' || name === '' ) {
                throw new Error( 'Name must be a string and must not be empty' );
        }
        this.entries.push( name );

        oo.Factory.super.prototype.register.call( this, name, constructor );
};

/**
 * Create an object based on a name.
 *
 * Name is used to look up the constructor to use, while all additional arguments are passed to the
 * constructor directly, so leaving one out will pass an undefined to the constructor.
 *
 * @param {string} name Object name
 * @param {Mixed...} [args] Arguments to pass to the constructor
 * @return {Object} The new object
 * @throws {Error} Unknown object name
 */
oo.Factory.prototype.create = function ( name ) {
        var args, obj, constructor;

        if ( !this.registry.hasOwnProperty( name ) ) {
                throw new Error( 'No class registered by that name: ' + name );
        }
        constructor = this.registry[name];

        // Convert arguments to array and shift the first argument (name) off
        args = Array.prototype.slice.call( arguments, 1 );

        // We can't use the "new" operator with .apply directly because apply needs a
        // context. So instead just do what "new" does: create an object that inherits from
        // the constructor's prototype (which also makes it an "instanceof" the constructor),
        // then invoke the constructor with the object as context, and return it (ignoring
        // the constructor's return value).
        obj = Object.create( constructor.prototype );
        constructor.apply( obj, args );
        return obj;
};
/*jshint node:true */
if ( typeof module !== 'undefined' && module.exports ) {
        module.exports = oo;
} else {
        global.OO = oo;
}
}( this ) );