var FILE_SYSTEM_NAME = require('../constants.js').FILE_SYSTEM_NAME; // NOTE: prefer setImmediate to nextTick for proper recursion yielding. // see https://github.com/js-platform/filer/pull/24 var asyncCallback = require('../../lib/async.js').setImmediate; /** * Make shared in-memory DBs possible when using the same name. */ var createDB = (function() { var pool = {}; return function getOrCreate(name) { if(!pool.hasOwnProperty(name)) { pool[name] = {}; } return pool[name]; }; }()); function MemoryContext(db, readOnly) { this.readOnly = readOnly; this.objectStore = db; } MemoryContext.prototype.clear = function(callback) { if(this.readOnly) { asyncCallback(function() { callback("[MemoryContext] Error: write operation on read only context"); }); return; } var objectStore = this.objectStore; Object.keys(objectStore).forEach(function(key){ delete objectStore[key]; }); asyncCallback(callback); }; // Memory context doesn't care about differences between Object and Buffer MemoryContext.prototype.getObject = MemoryContext.prototype.getBuffer = function(key, callback) { var that = this; asyncCallback(function() { callback(null, that.objectStore[key]); }); }; MemoryContext.prototype.putObject = MemoryContext.prototype.putBuffer = function(key, value, callback) { if(this.readOnly) { asyncCallback(function() { callback("[MemoryContext] Error: write operation on read only context"); }); return; } this.objectStore[key] = value; asyncCallback(callback); }; MemoryContext.prototype.delete = function(key, callback) { if(this.readOnly) { asyncCallback(function() { callback("[MemoryContext] Error: write operation on read only context"); }); return; } delete this.objectStore[key]; asyncCallback(callback); }; function Memory(name) { this.name = name || FILE_SYSTEM_NAME; } Memory.isSupported = function() { return true; }; Memory.prototype.open = function(callback) { this.db = createDB(this.name); asyncCallback(callback); }; Memory.prototype.getReadOnlyContext = function() { return new MemoryContext(this.db, true); }; Memory.prototype.getReadWriteContext = function() { return new MemoryContext(this.db, false); }; module.exports = Memory;