/*
* Copyright 2013 Jive Software
*
* Licensed 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.
*/
var q = require('q');
var jive = require('../../api');
var ArrayStream = require('stream-array');
/**
* An in-memory implementation of persistence.
* @module memoryPersistence
* @constructor
*/
module.exports = function() {
jive.logger.warn("******************************");
jive.logger.warn("Memory persistence is configured.");
jive.logger.warn("Please note that this should");
jive.logger.warn("not be used for production!");
jive.logger.warn("******************************");
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Private
/**
* In-memory data structure to use as a database
* @type {{}}
*/
var db = {};
/**
* Fetches a named collection from the db if collection exists; otherwise lazily create the collection.
* @param collectionID
* @return {*}
*/
var getCollection = function( collectionID ) {
var collection = db[collectionID];
if ( collection ) {
return collection;
} else {
collection = {};
db[collectionID] = collection;
return collection;
}
};
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Public
/**
* @inner
* @type {{save: Function, remove: Function, find: Function, findByID: Function, close: Function}}
*/
var memoryPersistence = {
/**
* Save the provided data in a named collection
* @memberof memoryPersistence
* @param {String} collectionID
* @param {String} key
* @param {Object} data
* @returns {Object} promise
*/
save: function( collectionID, key, data) {
return q.fcall( function () {
var collection = getCollection(collectionID);
collection[key] = data;
return data;
});
},
/**
* Remove a piece of data from a name collection, based to the provided key and return a promise
* that returns removed items when done.
* @memberof memoryPersistence
* @param {String} collectionID
* @param {String} key
* @returns {Object} promise
*/
remove: function( collectionID, key ) {
return q.fcall( function () {
var collection = getCollection(collectionID );
var removed = collection[key];
delete collection[key];
return removed;
});
},
/**
* Retrieve a piece of data from a named collection, based on the criteria, and returns a promise
* that contains found items when done.
* @memberof memoryPersistence
* @param {String} collectionID
* @param {Object} keyValues
* @param {Boolean} cursor If true, returns an iterable cursor.
* @returns {Object} promise
*/
find: function( collectionID, keyValues, cursor ) {
var p = q.defer();
var collectionItems = [];
var collection = getCollection(collectionID );
var findKeys = keyValues ? Object.keys( keyValues ) : undefined;
for (var colKey in collection) {
if (collection.hasOwnProperty(colKey)) {
var entryToInspect = collection[colKey];
var match = true;
if ( findKeys ) {
for ( var i in findKeys ) {
var findKey = findKeys[i];
var keyParts = findKey.split('.');
var entryObj = entryToInspect;
for ( var k = 0; k < keyParts.length; k++ ) {
var keyPart = keyParts[k];
if ( typeof entryObj == 'object' ) {
entryObj = entryObj[keyPart];
}
}
var keyValue = keyValues[ findKey ];
if ( typeof keyValue == 'object' ) {
if ( keyValue['$gt'] ) {
if ( entryObj <= keyValue['$gt'] ) {
match = false;
break;
}
}
if ( keyValue['$gte'] ) {
if ( entryObj < keyValue['$gte'] ) {
match = false;
break;
}
}
if ( keyValue['$lt'] ) {
if ( entryObj >= keyValue['$lt'] ) {
match = false;
break;
}
}
if ( keyValue['$lte'] ) {
if ( entryObj > keyValue['$lte'] ) {
match = false;
break;
}
}
if ( keyValue['$in'] ) {
if ( keyValue['$in'].indexOf(entryObj) < 0 ) {
match = false;
break;
}
}
} else {
if ( entryObj !== keyValue ) {
match = false;
break;
}
}
}
}
if ( match ) {
collectionItems.push( collection[colKey] );
}
}
}
if ( !cursor ) {
p.resolve( collectionItems );
} else {
var stream = ArrayStream(collectionItems);
// graft next method
stream.nextCtr = 0;
stream.fullCollection = collectionItems;
stream.next = function(processorFunction) {
if ( !processorFunction ) {
return null;
}
this.nextCtr++;
if ( this.nextCtr > this.fullCollection.length - 1 ) {
processorFunction(null, null);
} else {
processorFunction(null, this.fullCollection[this.nextCtr]);
}
};
p.resolve(stream );
}
return p.promise;
},
/**
* Retrieve a piece of data from a named collection whose key is the one provided.
* @memberof memoryPersistence
* @param collectionID
* @param key
* @returns {Object} promise
*/
findByID: function( collectionID, key ) {
return q.fcall( function() {
var collection = getCollection(collectionID );
return collection[key];
});
},
/**
* Close it down
* @memberof memoryPersistence
* @returns {Object} promise
*/
close: function() {
return q.resolve();
}
};
return memoryPersistence;
};