orange-orm/src/table/newCache.js

Object Relational Mapper

var newEmitEvent = require('../emitEvent');

function cacheCore() {
	var emitAdded = newEmitEvent();
	var emitRemoved = newEmitEvent();
	var c = {};
	var cache = {};
	var keyLength;

	c.tryGet = function(key) {
		var index = 0;
		var keyLength = key.length;

		return tryGetCore(cache, index);

		function tryGetCore(cache, index) {
			var keyValue = key[index];
			var cacheValue = cache[keyValue];
			if (typeof cacheValue === 'undefined')
				return null;
			if (keyLength - 1 === index)
				return cacheValue;
			return tryGetCore(cache[keyValue], ++index);
		}

	};

	c.tryAdd = function(key, result) {
		var index = 0;
		keyLength = key.length;

		return  addCore(cache, index);

		function addCore(cache, index) {
			var keyValue = key[index];

			if (keyLength - 1 === index) {
				if (keyValue in cache)
					return cache[keyValue];

				cache[keyValue] = result;
				emitAdded(result);
				return result;
			}
			if (! (keyValue in cache))
				cache[keyValue] = {};
			return addCore(cache[keyValue], ++index);
		}
	};

	c.tryRemove = function(key) {
		var index = 0;
		var keyLength = key.length;

		return tryRemoveCore(cache, index);

		function tryRemoveCore(cache, index) {
			var keyValue = key[index];
			if (!(keyValue in cache))
				return null;
			var cacheValue = cache[keyValue];
			if (keyLength - 1 === index) {
				delete cache[keyValue];
				emitRemoved(cacheValue);
				return cacheValue;
			}

			return tryRemoveCore(cache[keyValue], ++index);
		}

	};

	c.getAll = function() {
		var index = 0;
		var result = [];
		getAllCore(cache, index);

		function getAllCore(cache, index) {
			for (var name in cache) {
				var value = cache[name];
				if (index === keyLength - 1)
					result.push(value);
				else
					getAllCore(value, index+1);
			}
		}
		return result;
	};

	c.subscribeAdded = emitAdded.add;
	c.subscribeRemoved = emitRemoved.add;

	return c;
}

module.exports = cacheCore;