kvstore.js

/*jslint node: true */
"use strict";
var fs = require('fs');
var rocksdb = require('level-rocksdb');
var app_data_dir = require('./desktop_app.js').getAppDataDir();
var path = app_data_dir + '/rocksdb';

try{
	fs.statSync(app_data_dir);
}
catch(e){
	var mode = parseInt('700', 8);
	var parent_dir = require('path').dirname(app_data_dir);
	try { fs.mkdirSync(parent_dir, mode); } catch(e){}
	try { fs.mkdirSync(app_data_dir, mode); } catch(e){}
}

if (process.platform === 'win32') {
	var cwd = process.cwd();
	process.chdir(app_data_dir); // workaround non-latin characters in path
	path = 'rocksdb';
}
var db = rocksdb(path, {}, function (err) {
	if (err)
		throw Error("rocksdb open failed (is the app already running?): " + err);
	// if (process.platform === 'win32') // restore current working directory on windows
	// 	process.chdir(cwd);
});
if (!db)
	throw Error("no rocksdb instance");

module.exports = {
	get: function(key, cb){
		db.get(key, function(err, val){
			if (err){
				if (err.notFound)
					return cb();
				throw Error("get "+key+" failed: "+err);
			}
			cb(val);
		});
	},
	
	put: function(key, val, cb){
		db.put(key, val, function(err){
			if (err)
				throw Error("put "+key+" = "+val+" failed: "+err);
			cb();
		});
	},
	
	del: function(key, cb){
		db.del(key, function(err){
			if (err)
				throw Error("del " + key + " failed: " + err);
			if (cb)
				cb();
		});
	},
	
	batch: function(){
		return db.batch();
	},
	
	createReadStream: function(options){
		return db.createReadStream(options);
	},
	
	createKeyStream: function(options){
		return db.createKeyStream(options);
	},
	
	open: function(cb){
		if (db.isOpen()) return cb('already open');
		db.open(cb);
	},

	close: function(cb){
		if (db.isClosed()) return cb('already closed');
		db.close(cb);
	}
};