| 1 | const TAGS_PREFIX = 'hyperdrive-tags/'
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| 2 | const varint = require('varint')
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| 3 |
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| 4 | module.exports = class TagManager {
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| 5 | constructor (drive) {
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| 6 | this.drive = drive
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| 7 | }
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| 8 |
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| 9 | _toTag (name) {
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| 10 | return TAGS_PREFIX + name
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| 11 | }
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| 12 |
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| 13 | _fromTag (tag) {
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| 14 | return tag.slice(TAGS_PREFIX.length)
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| 15 | }
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| 16 |
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| 17 | create (name, version, cb) {
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| 18 | if (typeof version === 'function') {
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| 19 | cb = version
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| 20 | version = null
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| 21 | }
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| 22 | if (typeof name !== 'string') return cb(new Error('Tag name must be a string.'))
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| 23 | this.drive.ready(err => {
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| 24 | if (err) return cb(err)
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| 25 | if (version === null) version = this.drive.version
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| 26 | const buf = Buffer.alloc(varint.encodingLength(version))
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| 27 | varint.encode(version, buf)
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| 28 | return this.drive.db.put(this._toTag(name), buf, { hidden: true }, cb)
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| 29 | })
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| 30 | }
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| 31 |
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| 32 | get (name, cb) {
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| 33 | this.drive.ready(err => {
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| 34 | if (err) return cb(err)
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| 35 | this.drive.db.get(this._toTag(name), { hidden : true }, (err, node) => {
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| 36 | if (err) return cb(err)
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| 37 | if (!node) return cb(null, null)
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| 38 | return cb(null, varint.decode(node.value))
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| 39 | })
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| 40 | })
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| 41 | }
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| 42 |
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| 43 | getAll (cb) {
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| 44 | this.drive.ready(err => {
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| 45 | if (err) return cb(err)
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| 46 | this.drive.db.list(TAGS_PREFIX, { hidden: true }, (err, nodes) => {
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| 47 | if (err) return cb(err)
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| 48 | if (!nodes || !nodes.length) return cb(null, [])
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| 49 | const tagMap = new Map()
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| 50 | for (const node of nodes) {
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| 51 | tagMap.set(this._fromTag(node.key), varint.decode(node.value))
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| 52 | }
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| 53 | return cb(null, tagMap)
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| 54 | })
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| 55 | })
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| 56 | }
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| 57 |
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| 58 | delete (name, cb) {
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| 59 | this.drive.ready(err => {
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| 60 | if (err) return cb(err)
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| 61 | return this.drive.db.del(this._toTag(name), { hidden: true }, cb)
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| 62 | })
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| 63 | }
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| 64 | }
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