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