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							125 lines
						
					
					
						
							3.3 KiB
						
					
					
				
			
		
		
	
	
							125 lines
						
					
					
						
							3.3 KiB
						
					
					
				| 'use strict';
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| 
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| var GetIntrinsic = require('get-intrinsic');
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| var callBound = require('call-bind/callBound');
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| var inspect = require('object-inspect');
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| 
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| var $TypeError = GetIntrinsic('%TypeError%');
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| var $WeakMap = GetIntrinsic('%WeakMap%', true);
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| var $Map = GetIntrinsic('%Map%', true);
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| 
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| var $weakMapGet = callBound('WeakMap.prototype.get', true);
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| var $weakMapSet = callBound('WeakMap.prototype.set', true);
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| var $weakMapHas = callBound('WeakMap.prototype.has', true);
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| var $mapGet = callBound('Map.prototype.get', true);
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| var $mapSet = callBound('Map.prototype.set', true);
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| var $mapHas = callBound('Map.prototype.has', true);
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| 
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| /*
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|  * This function traverses the list returning the node corresponding to the
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|  * given key.
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|  *
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|  * That node is also moved to the head of the list, so that if it's accessed
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|  * again we don't need to traverse the whole list. By doing so, all the recently
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|  * used nodes can be accessed relatively quickly.
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|  */
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| var listGetNode = function (list, key) { // eslint-disable-line consistent-return
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| 	for (var prev = list, curr; (curr = prev.next) !== null; prev = curr) {
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| 		if (curr.key === key) {
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| 			prev.next = curr.next;
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| 			curr.next = list.next;
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| 			list.next = curr; // eslint-disable-line no-param-reassign
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| 			return curr;
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| 		}
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| 	}
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| };
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| 
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| var listGet = function (objects, key) {
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| 	var node = listGetNode(objects, key);
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| 	return node && node.value;
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| };
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| var listSet = function (objects, key, value) {
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| 	var node = listGetNode(objects, key);
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| 	if (node) {
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| 		node.value = value;
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| 	} else {
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| 		// Prepend the new node to the beginning of the list
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| 		objects.next = { // eslint-disable-line no-param-reassign
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| 			key: key,
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| 			next: objects.next,
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| 			value: value
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| 		};
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| 	}
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| };
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| var listHas = function (objects, key) {
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| 	return !!listGetNode(objects, key);
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| };
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| 
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| module.exports = function getSideChannel() {
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| 	var $wm;
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| 	var $m;
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| 	var $o;
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| 	var channel = {
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| 		assert: function (key) {
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| 			if (!channel.has(key)) {
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| 				throw new $TypeError('Side channel does not contain ' + inspect(key));
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| 			}
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| 		},
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| 		get: function (key) { // eslint-disable-line consistent-return
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| 			if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
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| 				if ($wm) {
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| 					return $weakMapGet($wm, key);
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| 				}
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| 			} else if ($Map) {
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| 				if ($m) {
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| 					return $mapGet($m, key);
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| 				}
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| 			} else {
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| 				if ($o) { // eslint-disable-line no-lonely-if
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| 					return listGet($o, key);
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| 				}
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| 			}
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| 		},
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| 		has: function (key) {
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| 			if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
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| 				if ($wm) {
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| 					return $weakMapHas($wm, key);
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| 				}
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| 			} else if ($Map) {
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| 				if ($m) {
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| 					return $mapHas($m, key);
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| 				}
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| 			} else {
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| 				if ($o) { // eslint-disable-line no-lonely-if
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| 					return listHas($o, key);
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| 				}
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| 			}
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| 			return false;
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| 		},
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| 		set: function (key, value) {
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| 			if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
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| 				if (!$wm) {
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| 					$wm = new $WeakMap();
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| 				}
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| 				$weakMapSet($wm, key, value);
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| 			} else if ($Map) {
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| 				if (!$m) {
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| 					$m = new $Map();
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| 				}
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| 				$mapSet($m, key, value);
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| 			} else {
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| 				if (!$o) {
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| 					/*
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| 					 * Initialize the linked list as an empty node, so that we don't have
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| 					 * to special-case handling of the first node: we can always refer to
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| 					 * it as (previous node).next, instead of something like (list).head
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| 					 */
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| 					$o = { key: {}, next: null };
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| 				}
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| 				listSet($o, key, value);
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| 			}
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| 		}
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| 	};
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| 	return channel;
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| };
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