| lib/flumeview-level.jsView |
|---|
| 1 | | - |
| 2 | | -var pull = require('pull-stream') |
| 3 | | -var Level = require('level') |
| 4 | | -var bytewise = require('bytewise') |
| 5 | | -var Write = require('pull-write') |
| 6 | | -var pl = require('pull-level') |
| 7 | | -var Obv = require('obv') |
| 8 | | -var path = require('path') |
| 9 | | -var Paramap = require('pull-paramap') |
| 10 | | -var ltgt = require('ltgt') |
| 11 | | -var explain = require('explain-error') |
| 12 | | - |
| 13 | | -module.exports = function (version, map) { |
| 14 | | - return function (log, name) { |
| 15 | | - var db = create(path), writer |
| 16 | | - |
| 17 | | - var META = '\x00', since = Obv() |
| 18 | | - |
| 19 | | - var written = 0, closed |
| 20 | | - |
| 21 | | - function create() { |
| 22 | | - closed = false |
| 23 | | - if(!log.filename) |
| 24 | | - throw new Error('flumeview-level can only be used with a log that provides a directory') |
| 25 | | - var dir = path.dirname(log.filename) |
| 26 | | - return Level(path.join(dir, name), {keyEncoding: bytewise, valueEncoding: 'json'}) |
| 27 | | - } |
| 28 | | - |
| 29 | | - function close (cb) { |
| 30 | | - closed = true |
| 31 | | - |
| 32 | | - if(writer) writer.abort(function () { db.close(cb) }) |
| 33 | | - else db.close(cb) |
| 34 | | - } |
| 35 | | - |
| 36 | | - function destroy (cb) { |
| 37 | | - close(function () { |
| 38 | | - var dbPath = path.join(path.dirname(log.filename), name) |
| 39 | | - Level.destroy(dbPath, cb) |
| 40 | | - }) |
| 41 | | - } |
| 42 | | - |
| 43 | | - db.get(META, {keyEncoding: 'utf8'}, function (err, value) { |
| 44 | | - if(err) since.set(-1) |
| 45 | | - else if(value.version === version) |
| 46 | | - since.set(value.since) |
| 47 | | - else |
| 48 | | - destroy(function () { |
| 49 | | - db = create(path); since.set(-1) |
| 50 | | - }) |
| 51 | | - }) |
| 52 | | - |
| 53 | | - var since = Obv() |
| 54 | | - |
| 55 | | - return { |
| 56 | | - since: since, |
| 57 | | - methods: { get: 'async', read: 'source'}, |
| 58 | | - createSink: function (cb) { |
| 59 | | - return writer = Write(function (batch, cb) { |
| 60 | | - if(closed) return cb(new Error('database closed while index was building')) |
| 61 | | - db.batch(batch, function (err) { |
| 62 | | - if(err) return cb(err) |
| 63 | | - since.set(batch[0].value.since) |
| 64 | | - |
| 65 | | - cb() |
| 66 | | - }) |
| 67 | | - }, function reduce (batch, data) { |
| 68 | | - if(data.sync) return batch |
| 69 | | - var seq = data.seq |
| 70 | | - |
| 71 | | - if(!batch) |
| 72 | | - batch = [{ |
| 73 | | - key: META, |
| 74 | | - value: {version: version, since: seq}, |
| 75 | | - valueEncoding: 'json', keyEncoding:'utf8', type: 'put' |
| 76 | | - }] |
| 77 | | - |
| 78 | | - |
| 79 | | - var indexed = map(data.value, data.seq) |
| 80 | | - batch = batch.concat(indexed.map(function (key) { return { key: key, value: seq, type: 'put' }})) |
| 81 | | - batch[0].value.since = Math.max(batch[0].value.since, seq) |
| 82 | | - return batch |
| 83 | | - }, 512, cb) |
| 84 | | - }, |
| 85 | | - |
| 86 | | - get: function (key, cb) { |
| 87 | | - |
| 88 | | - db.get(key, function (err, seq) { |
| 89 | | - if(err && err.name === 'NotFoundError') return cb(err) |
| 90 | | - if(err) cb(explain(err, 'flumeview-level.get: key not found:'+key)) |
| 91 | | - else |
| 92 | | - log.get(seq, function (err, value) { |
| 93 | | - if(err) cb(explain(err, 'flumeview-level.get: index for:'+key+'pointed at:'+seq+'but log error')) |
| 94 | | - else cb(null, value) |
| 95 | | - }) |
| 96 | | - }) |
| 97 | | - }, |
| 98 | | - read: function (opts) { |
| 99 | | - var keys = opts.keys |
| 100 | | - var values = opts.values |
| 101 | | - opts.keys = true; opts.values = true |
| 102 | | - |
| 103 | | - |
| 104 | | - var lower = ltgt.lowerBound(opts) |
| 105 | | - if(lower == null) opts.gt = null |
| 106 | | - |
| 107 | | - return pull( |
| 108 | | - pl.read(db, opts), |
| 109 | | - pull.filter(function (op) { |
| 110 | | - |
| 111 | | - return op.key !== '\u0000' |
| 112 | | - }), |
| 113 | | - Paramap(function (data, cb) { |
| 114 | | - if(data.sync) return cb(null, data) |
| 115 | | - log.get(data.value, function (err, value) { |
| 116 | | - if(err) cb(explain(err, 'when trying to retrive:'+data.key+'at since:'+log.since.value)) |
| 117 | | - else cb(null, {key: data.key, seq: data.value, value: value}) |
| 118 | | - }) |
| 119 | | - }) |
| 120 | | - ) |
| 121 | | - }, |
| 122 | | - close: close, |
| 123 | | - destroy: destroy |
| 124 | | - |
| 125 | | - } |
| 126 | | - } |
| 127 | | -} |