73 lines
2.2 KiB
JavaScript

'use strict'
const { AbstractKeyIterator, AbstractValueIterator } = require('../abstract-iterator')
const kIterator = Symbol('iterator')
const kCallback = Symbol('callback')
const kHandleOne = Symbol('handleOne')
const kHandleMany = Symbol('handleMany')
class DefaultKeyIterator extends AbstractKeyIterator {
constructor (db, options) {
super(db, options)
this[kIterator] = db.iterator({ ...options, keys: true, values: false })
this[kHandleOne] = this[kHandleOne].bind(this)
this[kHandleMany] = this[kHandleMany].bind(this)
}
}
class DefaultValueIterator extends AbstractValueIterator {
constructor (db, options) {
super(db, options)
this[kIterator] = db.iterator({ ...options, keys: false, values: true })
this[kHandleOne] = this[kHandleOne].bind(this)
this[kHandleMany] = this[kHandleMany].bind(this)
}
}
for (const Iterator of [DefaultKeyIterator, DefaultValueIterator]) {
const keys = Iterator === DefaultKeyIterator
const mapEntry = keys ? (entry) => entry[0] : (entry) => entry[1]
Iterator.prototype._next = function (callback) {
this[kCallback] = callback
this[kIterator].next(this[kHandleOne])
}
Iterator.prototype[kHandleOne] = function (err, key, value) {
const callback = this[kCallback]
if (err) callback(err)
else callback(null, keys ? key : value)
}
Iterator.prototype._nextv = function (size, options, callback) {
this[kCallback] = callback
this[kIterator].nextv(size, options, this[kHandleMany])
}
Iterator.prototype._all = function (options, callback) {
this[kCallback] = callback
this[kIterator].all(options, this[kHandleMany])
}
Iterator.prototype[kHandleMany] = function (err, entries) {
const callback = this[kCallback]
if (err) callback(err)
else callback(null, entries.map(mapEntry))
}
Iterator.prototype._seek = function (target, options) {
this[kIterator].seek(target, options)
}
Iterator.prototype._close = function (callback) {
this[kIterator].close(callback)
}
}
// Internal utilities, should be typed as AbstractKeyIterator and AbstractValueIterator
exports.DefaultKeyIterator = DefaultKeyIterator
exports.DefaultValueIterator = DefaultValueIterator