/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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';
/** @module store/memory */
var utils = require('./../utils.js');
// Imports.
var throwErrorCallback = utils.throwErrorCallback;
var delay = utils.delay;
/** Constructor for store objects that use a sorted array as the underlying mechanism.
* @class MemoryStore
* @constructor
* @param {String} name - Store name.
*/
function MemoryStore(name) {
var holes = [];
var items = [];
var keys = {};
this.name = name;
var getErrorCallback = function (error) {
return error || this.defaultError;
};
/** Validates that the specified key is not undefined, not null, and not an array
* @param key - Key value.
* @param {Function} error - Error callback.
* @returns {Boolean} True if the key is valid. False if the key is invalid and the error callback has been queued for execution.
*/
function validateKeyInput(key, error) {
var messageString;
if (key instanceof Array) {
messageString = "Array of keys not supported";
}
if (key === undefined || key === null) {
messageString = "Invalid key";
}
if (messageString) {
delay(error, { message: messageString });
return false;
}
return true;
}
/** This method errors out if the store already contains the specified key.
* @summary Adds a new value identified by a key to the store.
* @method module:store/memory~MemoryStore#add
* @param {String} key - Key string.
* @param value - Value that is going to be added to the store.
* @param {Function} success - Callback for a successful add operation.
* @param {Function} error - Callback for handling errors. If not specified then store.defaultError is invoked.
*/
this.add = function (key, value, success, error) {
error = getErrorCallback(error);
if (validateKeyInput(key, error)) {
if (!keys.hasOwnProperty(key)) {
this.addOrUpdate(key, value, success, error);
} else {
error({ message: "key already exists", key: key });
}
}
};
/** This method will overwrite the key's current value if it already exists in the store; otherwise it simply adds the new key and value.
* @summary Adds or updates a value identified by a key to the store.
* @method module:store/memory~MemoryStore#addOrUpdate
* @param {String} key - Key string.
* @param value - Value that is going to be added or updated to the store.
* @param {Function} success - Callback for a successful add or update operation.
* @param {Function} [error] - Callback for handling errors. If not specified then store.defaultError is invoked.
*/
this.addOrUpdate = function (key, value, success, error) {
error = getErrorCallback(error);
if (validateKeyInput(key, error)) {
var index = keys[key];
if (index === undefined) {
if (holes.length > 0) {
index = holes.splice(0, 1);
} else {
index = items.length;
}
}
items[index] = value;
keys[key] = index;
delay(success, key, value);
}
};
/** Removes all the data associated with this store object.
* @method module:store/memory~MemoryStore#clear
* @param {Function} success - Callback for a successful clear operation.
*/
this.clear = function (success) {
items = [];
keys = {};
holes = [];
delay(success);
};
/** Checks whether a key exists in the store.
* @method module:store/memory~MemoryStore#contains
* @param {String} key - Key string.
* @param {Function} success - Callback indicating whether the store contains the key or not.
*/
this.contains = function (key, success) {
var contained = keys.hasOwnProperty(key);
delay(success, contained);
};
/** Gets all the keys that exist in the store.
* @method module:store/memory~MemoryStore#getAllKeys
* @param {Function} success - Callback for a successful get operation.
*/
this.getAllKeys = function (success) {
var results = [];
for (var name in keys) {
results.push(name);
}
delay(success, results);
};
/** Reads the value associated to a key in the store.
* @method module:store/memory~MemoryStore#read
* @param {String} key - Key string.
* @param {Function} success - Callback for a successful reads operation.
* @param {Function} error - Callback for handling errors. If not specified then store.defaultError is invoked.
*/
this.read = function (key, success, error) {
error = getErrorCallback(error);
if (validateKeyInput(key, error)) {
var index = keys[key];
delay(success, key, items[index]);
}
};
/** Removes a key and its value from the store.
* @method module:store/memory~MemoryStore#remove
* @param {String} key - Key string.
* @param {Function} success - Callback for a successful remove operation.
* @param {Function} [error] - Callback for handling errors. If not specified then store.defaultError is invoked.
*/
this.remove = function (key, success, error) {
error = getErrorCallback(error);
if (validateKeyInput(key, error)) {
var index = keys[key];
if (index !== undefined) {
if (index === items.length - 1) {
items.pop();
} else {
items[index] = undefined;
holes.push(index);
}
delete keys[key];
// The last item was removed, no need to keep track of any holes in the array.
if (items.length === 0) {
holes = [];
}
}
delay(success);
}
};
/** Updates the value associated to a key in the store.
* @method module:store/memory~MemoryStore#update
* @param {String} key - Key string.
* @param value - New value.
* @param {Function} success - Callback for a successful update operation.
* @param {Function} [error] - Callback for handling errors. If not specified then store.defaultError is invoked.
* This method errors out if the specified key is not found in the store.
*/
this.update = function (key, value, success, error) {
error = getErrorCallback(error);
if (validateKeyInput(key, error)) {
if (keys.hasOwnProperty(key)) {
this.addOrUpdate(key, value, success, error);
} else {
error({ message: "key not found", key: key });
}
}
};
}
/** Creates a store object that uses memory storage as its underlying mechanism.
* @method MemoryStore.create
* @param {String} name - Store name.
* @returns {Object} Store object.
*/
MemoryStore.create = function (name) {
return new MemoryStore(name);
};
/** Checks whether the underlying mechanism for this kind of store objects is supported by the browser.
* @method MemoryStore.isSupported
* @returns {Boolean} True if the mechanism is supported by the browser; otherwise false.
*/
MemoryStore.isSupported = function () {
return true;
};
/** This function does nothing in MemoryStore as it does not have a connection model.
*/
MemoryStore.prototype.close = function () {
};
MemoryStore.prototype.defaultError = throwErrorCallback;
/** Identifies the underlying mechanism used by the store.
*/
MemoryStore.prototype.mechanism = "memory";
/** MemoryStore (see {@link MemoryStore}) */
module.exports = MemoryStore;