orange-orm/src/table/relation/newManyCacheCore.js

Object Relational Mapper

var newCacheCore = require('../newCache');
var newRowArray = require('../rowArray');

function newManyCache(joinRelation) {
	var c = {};
	var cache = newCacheCore();
	var primaryColumns = joinRelation.childTable._primaryColumns;

	c.tryGet = function(parentRow) {
		var key = toKey(parentRow);
		var rows =  cache.tryGet(key);
		if (!rows)
			return newArray();
		return rows;
	};

	function tryAdd(parentRow, childRow) {
		var key = toKey(parentRow);
		var existing = cache.tryGet(key);
		if(existing) {
			existing.push(childRow);
			return;
		}
		var rows = newArray();
		rows.push(childRow);
		existing = cache.tryAdd(key, rows);
	}

	function newArray() {
		return newRowArray(joinRelation.parentTable);
	}

	c.tryAdd = tryAdd;

	c.tryRemove = function(parentRow, childRow) {
		var key = toKey(parentRow);
		var existing = cache.tryGet(key);
		var index = existing.indexOf(childRow);
		existing.splice(index,1);
	};

	function toKey(row) {
		return primaryColumns.map(onColumn);

		function onColumn(column) {
			return row[column.alias];
		}
	}

	return c;
}

module.exports = newManyCache;