forked from Level/leveldown
-
Notifications
You must be signed in to change notification settings - Fork 0
/
snapshot.js
95 lines (77 loc) · 3.17 KB
/
snapshot.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
const xtend = require('xtend')
const AbstractLevelDOWN = require('./abstract-leveldown')
const Iterator = require('./iterator')
const IteratorStream = require('./iterator-stream')
function Snapshot (db, options) {
this.db = db
this.binding = db.binding.databaseSnapshot(options)
this._lockCounter = 1
}
Snapshot.prototype.get = AbstractLevelDOWN.prototype.get
Snapshot.prototype.iterator = AbstractLevelDOWN.prototype.iterator
Snapshot.prototype._setupIteratorOptions = AbstractLevelDOWN.prototype._setupIteratorOptions
Snapshot.prototype._serializeKey = AbstractLevelDOWN.prototype._serializeKey
Snapshot.prototype._serializeValue = AbstractLevelDOWN.prototype._serializeValue
Snapshot.prototype._checkKey = AbstractLevelDOWN.prototype._checkKey
Snapshot.prototype._serializeValue = function(value) {
return this.db._serializeValue(value)
}
Snapshot.prototype._deserializeValue = function(value) {
return this.db._deserializeValue(value)
}
Snapshot.prototype._serializeKey = function(key) {
return this.db._serializeKey(key)
}
Snapshot.prototype._deserializeKey = function(key) {
return this.db._deserializeKey(key)
}
Snapshot.prototype.begin = function () {
if (this._lockCounter === 0) throw new Error('Snapshot already closed.')
this._lockCounter++
}
Snapshot.prototype.end = function () {
if (this._lockCounter === 0) throw new Error('Inconsistent calls to Snapshot._lock() / Snapshot._unlock().')
this._lockCounter--
if (this._lockCounter === 0) {
this.binding.close()
}
}
Snapshot.prototype._get = function (key, options, callback) {
if (this._lockCounter === 0) return setImmediate(callback, new Error('Snapshot already closed.'))
return this.binding.get(key, options, callback)
}
Snapshot.prototype.getSync = function (key) {
if (this._lockCounter === 0) throw new Error('Snapshot already closed.')
return this.binding.getSync(key)
}
Snapshot.prototype._iterator = function (options) {
this.begin()
options = xtend({ databaseSnapshot: this.binding }, options)
const iterator = new Iterator(this.db, options)
iterator._snapshot = this
iterator._end = endIterator
return iterator
}
Snapshot.prototype.createReadStream = function (options) {
if (this._lockCounter === 0) throw new Error('Snapshot already closed.')
options = xtend({ keys: true, values: true }, options)
if (typeof options.limit !== 'number') { options.limit = -1 }
return new IteratorStream(this.iterator(options), options)
}
Snapshot.prototype.createKeyStream = function (options) {
if (this._lockCounter === 0) throw new Error('Snapshot already closed.')
options = xtend({ keys: true, values: false }, options)
if (typeof options.limit !== 'number') { options.limit = -1 }
return new IteratorStream(this.iterator(options), options)
}
Snapshot.prototype.createValueStream = function (options) {
if (this._lockCounter === 0) throw new Error('Snapshot already closed.')
options = xtend({ keys: false, values: true }, options)
if (typeof options.limit !== 'number') { options.limit = -1 }
return new IteratorStream(this.iterator(options), options)
}
function endIterator (callback) {
this._snapshot.end()
Iterator.prototype._end.call(this, callback)
}
module.exports = Snapshot