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+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// The possible return values of getTypeOf.
+const VALID_TYPES = [
+ "array",
+ "boolean",
+ "function",
+ "null",
+ "number",
+ "object",
+ "string",
+ "undefined",
+];
+
+/**
+ * Returns a function C that creates instances of privateCtor. C may be called
+ * with or without the new keyword. The prototype of each instance returned
+ * from C is C.prototype, and C.prototype is an object whose prototype is
+ * privateCtor.prototype. Instances returned from C will therefore be instances
+ * of both C and privateCtor. Additionally, the constructor of each instance
+ * returned from C is C.
+ *
+ * @param privateCtor
+ * A constructor.
+ * @return A function that makes new instances of privateCtor.
+ */
+exports.publicConstructor = function publicConstructor(privateCtor) {
+ function PublicCtor() {
+ let obj = { constructor: PublicCtor, __proto__: PublicCtor.prototype };
+ memory.track(obj, privateCtor.name);
+ privateCtor.apply(obj, arguments);
+ return obj;
+ }
+ PublicCtor.prototype = { __proto__: privateCtor.prototype };
+ return PublicCtor;
+};
+
+/**
+ * Returns a validated options dictionary given some requirements. If any of
+ * the requirements are not met, an exception is thrown.
+ *
+ * @param options
+ * An object, the options dictionary to validate. It's not modified.
+ * If it's null or otherwise falsey, an empty object is assumed.
+ * @param requirements
+ * An object whose keys are the expected keys in options. Any key in
+ * options that is not present in requirements is ignored. Each value
+ * in requirements is itself an object describing the requirements of
+ * its key. There are four optional keys in this object:
+ * map: A function that's passed the value of the key in options.
+ * map's return value is taken as the key's value in the final
+ * validated options, is, and ok. If map throws an exception
+ * it's caught and discarded, and the key's value is its value in
+ * options.
+ * is: An array containing any number of the typeof type names. If
+ * the key's value is none of these types, it fails validation.
+ * Arrays and null are identified by the special type names
+ * "array" and "null"; "object" will not match either. No type
+ * coercion is done.
+ * ok: A function that's passed the key's value. If it returns
+ * false, the value fails validation.
+ * msg: If the key's value fails validation, an exception is thrown.
+ * This string will be used as its message. If undefined, a
+ * generic message is used, unless is is defined, in which case
+ * the message will state that the value needs to be one of the
+ * given types.
+ * @return An object whose keys are those keys in requirements that are also in
+ * options and whose values are the corresponding return values of map
+ * or the corresponding values in options. Note that any keys not
+ * shared by both requirements and options are not in the returned
+ * object.
+ */
+exports.validateOptions = function validateOptions(options, requirements) {
+ options = options || {};
+ let validatedOptions = {};
+ let mapThrew = false;
+
+ for (let [key, req] in Iterator(requirements)) {
+ let [optsVal, keyInOpts] = (key in options) ?
+ [options[key], true] :
+ [undefined, false];
+ if (req.map) {
+ try {
+ optsVal = req.map(optsVal);
+ }
+ catch (err) {
+ mapThrew = true;
+ }
+ }
+ if (req.is) {
+ // Sanity check the caller's type names.
+ req.is.forEach(function (typ) {
+ if (VALID_TYPES.indexOf(typ) < 0) {
+ let msg = 'Internal error: invalid requirement type "' + typ + '".';
+ throw new Error(msg);
+ }
+ });
+ if (req.is.indexOf(getTypeOf(optsVal)) < 0)
+ throw requirementError(key, req);
+ }
+ if (req.ok && !req.ok(optsVal))
+ throw requirementError(key, req);
+
+ if (keyInOpts || (req.map && !mapThrew))
+ validatedOptions[key] = optsVal;
+ }
+
+ return validatedOptions;
+};
+
+exports.addIterator = function addIterator(obj, keysValsGenerator) {
+ obj.__iterator__ = function(keysOnly, keysVals) {
+ let keysValsIterator = keysValsGenerator.call(this);
+
+ // "for (.. in ..)" gets only keys, "for each (.. in ..)" gets values,
+ // and "for (.. in Iterator(..))" gets [key, value] pairs.
+ let index = keysOnly ? 0 : 1;
+ while (true)
+ yield keysVals ? keysValsIterator.next() : keysValsIterator.next()[index];
+ };
+};
+
+// Similar to typeof, except arrays and null are identified by "array" and
+// "null", not "object".
+let getTypeOf = exports.getTypeOf = function getTypeOf(val) {
+ let typ = typeof(val);
+ if (typ === "object") {
+ if (!val)
+ return "null";
+ if (Array.isArray(val))
+ return "array";
+ }
+ return typ;
+}
+
+// Returns a new Error with a nice message.
+function requirementError(key, requirement) {
+ let msg = requirement.msg;
+ if (!msg) {
+ msg = 'The option "' + key + '" ';
+ msg += requirement.is ?
+ "must be one of the following types: " + requirement.is.join(", ") :
+ "is invalid.";
+ }
+ return new Error(msg);
+}