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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);
}
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