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