db: rewrite lowlevelup without asyncobject.
This commit is contained in:
Christopher Jeffrey
parent
e52eebd652
commit
f2ab1611e4
@ -7,18 +7,16 @@
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'use strict';
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var util = require('../utils/util');
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var assert = require('assert');
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var AsyncObject = require('../utils/asyncobject');
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var util = require('../utils/util');
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var Lock = require('../utils/lock');
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var co = require('../utils/co');
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var VERSION_ERROR;
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/**
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* Extremely low-level version of levelup.
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* The only levelup feature it provides is
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* error-wrapping. It gives a nice recallable
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* `open()` method and event. It assumes ascii
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* keys and binary values.
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* error-wrapping.
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*
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* This avoids pulling in extra deps and
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* lowers memory usage.
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@ -33,12 +31,19 @@ function LowlevelUp(file, options) {
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if (!(this instanceof LowlevelUp))
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return new LowlevelUp(file, options);
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AsyncObject.call(this);
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assert(typeof file === 'string', 'Filename is required.');
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assert(options, 'Options are required.');
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assert(options.db, 'Database backend is required.');
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this.options = options;
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this.backend = options.db;
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this.location = file;
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this.bufferKeys = options.bufferKeys === true;
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this.locker = new Lock();
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this.loading = false;
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this.closing = false;
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this.loaded = false;
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this.db = new options.db(file);
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@ -53,15 +58,94 @@ function LowlevelUp(file, options) {
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this.binding = this.db.binding;
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}
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util.inherits(LowlevelUp, AsyncObject);
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/**
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* Open the database (recallable).
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* @alias LowlevelUp#open
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* Open the database.
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* @returns {Promise}
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*/
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LowlevelUp.prototype._open = function open() {
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LowlevelUp.prototype.open = co(function* open() {
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var unlock = yield this.locker.lock();
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try {
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return yield this._open();
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} finally {
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unlock();
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}
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});
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/**
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* Close the database.
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* @returns {Promise}
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*/
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LowlevelUp.prototype.close = co(function* close() {
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var unlock = yield this.locker.lock();
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try {
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return yield this._close();
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} finally {
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unlock();
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}
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});
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/**
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* Open the database (without a lock).
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* @private
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* @returns {Promise}
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*/
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LowlevelUp.prototype._open = co(function* open() {
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if (this.loaded)
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throw new Error('Database is already open.');
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assert(!this.loading);
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assert(!this.closing);
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this.loading = true;
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try {
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yield this.load();
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} catch (e) {
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this.loading = false;
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throw e;
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}
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this.loading = false;
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this.loaded = true;
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});
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/**
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* Close the database (without a lock).
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* @private
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* @returns {Promise}
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*/
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LowlevelUp.prototype._close = co(function* close() {
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if (!this.loaded)
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throw new Error('Database is already closed.');
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assert(!this.loading);
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assert(!this.closing);
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this.loaded = false;
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this.closing = true;
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try {
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yield this.unload();
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} catch (e) {
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this.loaded = true;
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this.closing = false;
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throw e;
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}
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this.closing = false;
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});
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/**
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* Open the database.
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* @private
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* @returns {Promise}
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*/
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LowlevelUp.prototype.load = function load() {
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var self = this;
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return new Promise(function(resolve, reject) {
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self.binding.open(self.options, co.wrap(resolve, reject));
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@ -69,12 +153,12 @@ LowlevelUp.prototype._open = function open() {
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};
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/**
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* Close the database (recallable).
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* @alias LowlevelUp#close
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* Close the database.
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* @private
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* @returns {Promise}
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*/
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LowlevelUp.prototype._close = function close() {
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LowlevelUp.prototype.unload = function unload() {
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var self = this;
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return new Promise(function(resolve, reject) {
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self.binding.close(co.wrap(resolve, reject));
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@ -89,13 +173,17 @@ LowlevelUp.prototype._close = function close() {
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LowlevelUp.prototype.destroy = function destroy() {
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var self = this;
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assert(!this.loading);
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assert(!this.closing);
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assert(!this.loaded);
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return new Promise(function(resolve, reject) {
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if (!self.backend.destroy)
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return reject(new Error('Cannot destroy.'));
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if (self.loaded || self.closing) {
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reject(new Error('Cannot destroy open database.'));
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return;
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}
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if (!self.backend.destroy) {
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reject(new Error('Cannot destroy (method not available).'));
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return;
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}
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self.backend.destroy(self.location, co.wrap(resolve, reject));
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});
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};
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@ -108,13 +196,17 @@ LowlevelUp.prototype.destroy = function destroy() {
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LowlevelUp.prototype.repair = function repair() {
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var self = this;
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assert(!this.loading);
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assert(!this.closing);
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assert(!this.loaded);
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return new Promise(function(resolve, reject) {
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if (!self.backend.repair)
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return reject(new Error('Cannot repair.'));
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if (self.loaded || self.closing) {
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reject(new Error('Cannot repair open database.'));
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return;
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}
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if (!self.backend.repair) {
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reject(new Error('Cannot repair (method not available).'));
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return;
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}
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self.backend.repair(self.location, co.wrap(resolve, reject));
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});
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};
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@ -128,14 +220,14 @@ LowlevelUp.prototype.repair = function repair() {
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LowlevelUp.prototype.backup = function backup(path) {
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var self = this;
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assert(!this.loading);
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assert(!this.closing);
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assert(this.loaded);
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if (!this.binding.backup)
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return this.clone(path);
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return new Promise(function(resolve, reject) {
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if (!self.loaded) {
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reject(new Error('Database is closed.'));
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return;
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}
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self.binding.backup(path, co.wrap(resolve, reject));
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});
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};
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@ -148,10 +240,11 @@ LowlevelUp.prototype.backup = function backup(path) {
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LowlevelUp.prototype.get = function get(key) {
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var self = this;
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assert(this.loaded, 'Cannot use database before it is loaded.');
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return new Promise(function(resolve, reject) {
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if (!self.loaded) {
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reject(new Error('Database is closed.'));
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return;
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}
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self.binding.get(key, function(err, result) {
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if (err) {
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if (isNotFound(err))
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@ -172,8 +265,11 @@ LowlevelUp.prototype.get = function get(key) {
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LowlevelUp.prototype.put = function put(key, value) {
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var self = this;
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assert(this.loaded, 'Cannot use database before it is loaded.');
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return new Promise(function(resolve, reject) {
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if (!self.loaded) {
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reject(new Error('Database is closed.'));
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return;
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}
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self.binding.put(key, value, co.wrap(resolve, reject));
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});
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};
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@ -186,8 +282,11 @@ LowlevelUp.prototype.put = function put(key, value) {
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LowlevelUp.prototype.del = function del(key) {
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var self = this;
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assert(this.loaded, 'Cannot use database before it is loaded.');
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return new Promise(function(resolve, reject) {
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if (!self.loaded) {
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reject(new Error('Database is closed.'));
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return;
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}
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self.binding.del(key, co.wrap(resolve, reject));
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});
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};
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@ -201,12 +300,17 @@ LowlevelUp.prototype.del = function del(key) {
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LowlevelUp.prototype.batch = function batch(ops) {
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var self = this;
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assert(this.loaded, 'Cannot use database before it is loaded.');
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if (!ops)
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if (!ops) {
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if (!this.loaded)
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throw new Error('Database is closed.');
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return new Batch(this);
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}
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return new Promise(function(resolve, reject) {
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if (!self.loaded) {
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reject(new Error('Database is closed.'));
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return;
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}
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self.binding.batch(ops, co.wrap(resolve, reject));
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});
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};
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@ -220,7 +324,8 @@ LowlevelUp.prototype.batch = function batch(ops) {
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LowlevelUp.prototype.iterator = function iterator(options) {
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var opt;
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assert(this.loaded, 'Cannot use database before it is loaded.');
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if (!this.loaded)
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throw new Error('Database is closed.');
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opt = {
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gte: options.gte,
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@ -254,7 +359,8 @@ LowlevelUp.prototype.iterator = function iterator(options) {
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*/
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LowlevelUp.prototype.getProperty = function getProperty(name) {
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assert(this.loaded, 'Cannot use database before it is loaded.');
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if (!this.loaded)
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throw new Error('Database is closed.');
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if (!this.binding.getProperty)
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return '';
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@ -272,11 +378,16 @@ LowlevelUp.prototype.getProperty = function getProperty(name) {
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LowlevelUp.prototype.approximateSize = function approximateSize(start, end) {
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var self = this;
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assert(this.loaded, 'Cannot use database before it is loaded.');
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return new Promise(function(resolve, reject) {
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if (!self.binding.approximateSize)
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return reject(new Error('Cannot get size.'));
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if (!self.loaded) {
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reject(new Error('Database is closed.'));
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return;
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}
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if (!self.binding.approximateSize) {
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reject(new Error('Cannot get size.'));
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return;
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}
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self.binding.approximateSize(start, end, co.wrap(resolve, reject));
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});
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@ -483,9 +594,8 @@ LowlevelUp.prototype.clone = co(function* clone(path) {
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var total = 0;
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var tmp, batch, iter, item;
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assert(!this.loading);
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assert(!this.closing);
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assert(this.loaded);
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if (!this.loaded)
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throw new Error('Database is closed.');
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options.createIfMissing = true;
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options.errorIfExists = true;
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