/toolkit/content/Dict.jsm
http://github.com/zpao/v8monkey · Unknown · 268 lines · 246 code · 22 blank · 0 comment · 0 complexity · 7b84e3842b94d77b0e91531edad620b4 MD5 · raw file
- /* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is dict.js.
- *
- * The Initial Developer of the Original Code is
- * the Mozilla Foundation.
- * Portions created by the Initial Developer are Copyright (C) 2010
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- * Siddharth Agarwal <sid.bugzilla@gmail.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- "use strict";
- var EXPORTED_SYMBOLS = ["Dict"];
- /**
- * Transforms a given key into a property name guaranteed not to collide with
- * any built-ins.
- */
- function convert(aKey) {
- return ":" + aKey;
- }
- /**
- * Transforms a property into a key suitable for providing to the outside world.
- */
- function unconvert(aProp) {
- return aProp.substr(1);
- }
- /**
- * A dictionary of strings to arbitrary JS objects. This should be used whenever
- * the keys are potentially arbitrary, to avoid collisions with built-in
- * properties.
- *
- * @param aInitial An object containing the initial keys and values of this
- * dictionary. Only the "own" enumerable properties of the
- * object are considered.
- */
- function Dict(aInitial) {
- if (aInitial === undefined)
- aInitial = {};
- var items = {}, count = 0;
- // That we don't look up the prototype chain is guaranteed by Iterator.
- for (var [key, val] in Iterator(aInitial)) {
- items[convert(key)] = val;
- count++;
- }
- this._state = {count: count, items: items};
- return Object.freeze(this);
- }
- Dict.prototype = Object.freeze({
- /**
- * The number of items in the dictionary.
- */
- get count() {
- return this._state.count;
- },
- /**
- * Gets the value for a key from the dictionary. If the key is not a string,
- * it will be converted to a string before the lookup happens.
- *
- * @param aKey The key to look up
- * @param [aDefault] An optional default value to return if the key is not
- * present. Defaults to |undefined|.
- * @returns The item, or aDefault if it isn't found.
- */
- get: function Dict_get(aKey, aDefault) {
- var prop = convert(aKey);
- var items = this._state.items;
- return items.hasOwnProperty(prop) ? items[prop] : aDefault;
- },
- /**
- * Sets the value for a key in the dictionary. If the key is a not a string,
- * it will be converted to a string before the set happens.
- */
- set: function Dict_set(aKey, aValue) {
- var prop = convert(aKey);
- var items = this._state.items;
- if (!items.hasOwnProperty(prop))
- this._state.count++;
- items[prop] = aValue;
- },
- /**
- * Sets a lazy getter function for a key's value. If the key is a not a string,
- * it will be converted to a string before the set happens.
- * @param aKey
- * The key to set
- * @param aThunk
- * A getter function to be called the first time the value for aKey is
- * retrieved. It is guaranteed that aThunk wouldn't be called more
- * than once. Note that the key value may be retrieved either
- * directly, by |get|, or indirectly, by |listvalues| or by iterating
- * |values|. For the later, the value is only retrieved if and when
- * the iterator gets to the value in question. Also note that calling
- * |has| for a lazy-key does not invoke aThunk.
- *
- * @note No context is provided for aThunk when it's invoked.
- * Use Function.bind if you wish to run it in a certain context.
- */
- setAsLazyGetter: function Dict_setAsLazyGetter(aKey, aThunk) {
- let prop = convert(aKey);
- let items = this._state.items;
- if (!items.hasOwnProperty(prop))
- this._state.count++;
- Object.defineProperty(items, prop, {
- get: function() {
- delete items[prop];
- return items[prop] = aThunk();
- },
- configurable: true,
- enumerable: true
- });
- },
- /**
- * Returns whether a key is set as a lazy getter. This returns
- * true only if the getter function was not called already.
- * @param aKey
- * The key to look up.
- * @returns whether aKey is set as a lazy getter.
- */
- isLazyGetter: function Dict_isLazyGetter(aKey) {
- let descriptor = Object.getOwnPropertyDescriptor(this._state.items,
- convert(aKey));
- return (descriptor && descriptor.get != null);
- },
- /**
- * Returns whether a key is in the dictionary. If the key is a not a string,
- * it will be converted to a string before the lookup happens.
- */
- has: function Dict_has(aKey) {
- return (this._state.items.hasOwnProperty(convert(aKey)));
- },
- /**
- * Deletes a key from the dictionary. If the key is a not a string, it will be
- * converted to a string before the delete happens.
- *
- * @returns true if the key was found, false if it wasn't.
- */
- del: function Dict_del(aKey) {
- var prop = convert(aKey);
- if (this._state.items.hasOwnProperty(prop)) {
- delete this._state.items[prop];
- this._state.count--;
- return true;
- }
- return false;
- },
- /**
- * Returns a shallow copy of this dictionary.
- */
- copy: function Dict_copy() {
- var newItems = {};
- for (var [key, val] in this.items)
- newItems[key] = val;
- return new Dict(newItems);
- },
- /*
- * List and iterator functions
- *
- * No guarantees whatsoever are made about the order of elements.
- */
- /**
- * Returns a list of all the keys in the dictionary in an arbitrary order.
- */
- listkeys: function Dict_listkeys() {
- return [unconvert(k) for (k in this._state.items)];
- },
- /**
- * Returns a list of all the values in the dictionary in an arbitrary order.
- */
- listvalues: function Dict_listvalues() {
- var items = this._state.items;
- return [items[k] for (k in items)];
- },
- /**
- * Returns a list of all the items in the dictionary as key-value pairs
- * in an arbitrary order.
- */
- listitems: function Dict_listitems() {
- var items = this._state.items;
- return [[unconvert(k), items[k]] for (k in items)];
- },
- /**
- * Returns an iterator over all the keys in the dictionary in an arbitrary
- * order. No guarantees are made about what happens if the dictionary is
- * mutated during iteration.
- */
- get keys() {
- // If we don't capture this._state.items here then the this-binding will be
- // incorrect when the generator is executed
- var items = this._state.items;
- return (unconvert(k) for (k in items));
- },
- /**
- * Returns an iterator over all the values in the dictionary in an arbitrary
- * order. No guarantees are made about what happens if the dictionary is
- * mutated during iteration.
- */
- get values() {
- // If we don't capture this._state.items here then the this-binding will be
- // incorrect when the generator is executed
- var items = this._state.items;
- return (items[k] for (k in items));
- },
- /**
- * Returns an iterator over all the items in the dictionary as key-value pairs
- * in an arbitrary order. No guarantees are made about what happens if the
- * dictionary is mutated during iteration.
- */
- get items() {
- // If we don't capture this._state.items here then the this-binding will be
- // incorrect when the generator is executed
- var items = this._state.items;
- return ([unconvert(k), items[k]] for (k in items));
- },
- /**
- * Returns a string representation of this dictionary.
- */
- toString: function Dict_toString() {
- return "{" +
- [(key + ": " + val) for ([key, val] in this.items)].join(", ") +
- "}";
- },
- });