fcoin/lib/db/ldb.js
2016-10-02 23:24:11 -07:00

143 lines
3.0 KiB
JavaScript

/**
* global ldb tracker
* @module ldb
* @license
* Copyright (c) 2014-2015, Fedor Indutny (MIT License)
* Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
* https://github.com/bcoin-org/bcoin
*/
'use strict';
var LowlevelUp = require('./lowlevelup');
var utils = require('../utils/utils');
var assert = require('assert');
/**
* @param {Object} options
* @param {Boolean} options.compression
* @param {Number} options.cacheSize
* @param {Number} options.writeBufferSize
* @param {Number} options.maxOpenFiles
* @param {Boolean} options.sync
* @param {Number} options.mapSize
* @param {Boolean} options.writeMap
* @param {String} options.db - Database backend (`"leveldb"` by default).
* @param {String} options.name - Database name.
* @param {String} options.location - Database location (overrides `name`).
* @returns {LowlevelUp}
*/
function ldb(options) {
var target = ldb.getTarget(options);
if (target.backend !== 'rbt')
utils.mkdir(target.location, true);
return new LowlevelUp(target.location, {
// Generic
createIfMissing: options.createIfMissing !== false,
errorIfExists: options.errorIfExists === true,
// LevelDB
compression: options.compression !== false,
cacheSize: options.cacheSize || (8 << 20),
writeBufferSize: options.writeBufferSize || (4 << 20),
maxOpenFiles: options.maxOpenFiles || 64,
paranoidChecks: false,
memory: false,
// LMDB
sync: options.sync || false,
mapSize: options.mapSize || 256 * (1024 << 20),
writeMap: options.writeMap || false,
noSubdir: options.noSubdir !== false,
// Browser
bufferKeys: options.bufferKeys,
db: target.db
});
}
/**
* Get database name and extension based on options.
* @param {String} db
* @returns {Object}
*/
ldb.getBackend = function getBackend(db) {
var name, ext;
if (!db)
db = 'memory';
switch (db) {
case 'ldb':
case 'leveldb':
case 'leveldown':
name = 'leveldown';
ext = 'ldb';
break;
case 'rdb':
case 'rocksdb':
case 'rocksdown':
name = 'rocksdown';
ext = 'rdb';
break;
case 'mdb':
case 'lmdb':
name = 'lmdb';
ext = 'mdb';
break;
case 'mem':
case 'memory':
case 'rbt':
name = 'rbt';
ext = 'mem';
break;
default:
name = db;
ext = 'db';
break;
}
return { name: name, ext: ext };
};
/**
* Get target backend and location.
* @param {Object} options
* @returns {Object}
*/
ldb.getTarget = function getTarget(options) {
var backend = ldb.getBackend(options.db);
var location = options.location;
var db;
if (backend.name === 'rbt')
db = require('./rbt');
else if (utils.isBrowser)
db = require('./level');
else
db = require(backend.name);
if (typeof location !== 'string') {
assert(backend.name === 'rbt', 'Location required.');
location = 'rbt';
}
return {
db: db,
backend: backend.name,
location: location + '.' + backend.ext
};
};
/*
* Expose
*/
module.exports = ldb;