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/**
* @license Apache-2.0
*
* Copyright (c) 2019 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var logger = require( 'debug' );
var hasOwnProp = require( '@stdlib/assert/has-own-property' );
var setConfigurableReadOnly = require( '@stdlib/utils/define-configurable-read-only-property' );
var setMemoizedConfigurableReadOnly = require( '@stdlib/utils/define-memoized-configurable-read-only-property' ); // eslint-disable-line id-length
var contains = require( './contains.js' );
var createAccessor = require( './create_accessor.js' );
var ALIASES = require( './aliases.js' );
// VARIABLES //
var debug = logger( 'repl:set_aliases_global' );
// FUNCTIONS //
/**
* Tests whether an alias is already accounted for in a global variable name list.
*
* @private
* @param {Array} list - list of global variable names
* @param {Array} path - alias "path"
* @returns {boolean} boolean indicating whether an alias is already accounted for
*/
function hasAliasPath( list, path ) {
var tmp;
var N;
var v;
var i;
var j;
N = path.length;
tmp = [ path[ 0 ] ];
for ( i = 1; i < N; i++ ) {
tmp.push( tmp[ i-1 ]+'.'+tmp[ i ] );
}
for ( i = 0; i < list.length; i++ ) {
v = list[ i ];
for ( j = 0; j < N; j++ ) {
if ( v === tmp[ j ] ) {
return true;
}
}
}
return false;
}
// MAIN //
/**
* Sets aliases on a non-sandboxed `context` object.
*
* ## Notes
*
* - This function avoids overwriting properties in a non-sandboxed environment in order to avoid unintended side-effects.
*
* @private
* @param {Array} out1 - output array for storing a list of global variables added to the global namespace
* @param {Array} out2 - strided output array for storing resolved module exports
* @param {Object} context - context object
* @param {Array} skip - list of aliases to skip
* @returns {Object} context object
*/
function setAliasesGlobal( out1, out2, context, skip ) {
var alias;
var key;
var FLG;
var N;
var o;
var p;
var i;
var j;
var k;
N = skip.length;
// Extend the context object, keeping in mind that an alias may be nested (e.g., `a.b.c`), and, if so, we need to generate nested objects...
for ( i = 0; i < ALIASES.length; i++ ) {
alias = ALIASES[ i ];
if ( contains( N, skip, 1, 0, alias ) ) {
continue;
}
o = context;
FLG = false;
key = alias.split( '.' );
for ( j = 0; j < key.length-1; j++ ) {
k = key[ j ];
if ( !hasOwnProp( o, k ) ) {
// Upon first encountering a new property, we need to remember the current key path, so that we can later remove the properties upon closing the REPL...
p = key.slice( 0, j+1 );
if ( FLG === false && !hasAliasPath( out1, p ) ) {
FLG = true;
out1.push( p.join( '.' ) );
}
setConfigurableReadOnly( o, k, {} );
}
o = o[ k ];
}
k = key[ j ];
// Avoid overwriting properties in a non-sandboxed environment in order to avoid unintended side-effects (e.g., don't break an already running application which has already defined a particular global variable)...
if ( hasOwnProp( o, k ) ) {
debug( 'Skipping alias as global context property `'+alias+'` is already assigned.' );
} else {
if ( FLG === false && !hasAliasPath( out1, key ) ) {
out1.push( alias );
}
setMemoizedConfigurableReadOnly( o, k, createAccessor( out2, context.require, alias ) ); // eslint-disable-line max-len
}
}
return context;
}
// EXPORTS //
module.exports = setAliasesGlobal;
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