git ssb

1
var nest = require('depnest')
2
var pull = require('pull-stream')
3
var pullCat = require('pull-cat')
4
var sort = require('ssb-sort')
5
var ref = require('ssb-ref')
6
var { map, computed } = require('mutant')
7
8
exports.needs = nest({
9
  'sbot.pull.links': 'first',
10
  'sbot.async.get': 'first',
11
  'lib.obs.pullLookup': 'first',
12
  'message.sync.unbox': 'first'
13
})
14
15
exports.gives = nest('feed.obs.thread')
16
17
exports.create = function (api) {
18
  return nest('feed.obs.thread', function (rootId, {branch}) {
19
    if (!ref.isLink(rootId)) throw new Error('an id must be specified')
20
21
    var rootMessageStream = pull(
22
      pull.values([rootId]),
23
      pull.asyncMap((key, cb) => {
24
        return api.sbot.async.get(key, (err, value) => cb(err, {key, value}))
25
      })
26
    )
27
28
    var messageLookup = api.lib.obs.pullLookup(pull(
29
      pullCat([
30
        rootMessageStream,
31
        api.sbot.pull.links({ rel: branch ? 'branch' : 'root', dest: rootId, keys: true, values: true, live: true })
32
      ]),
33
      unboxIfNeeded()
34
    ), 'key')
35
36
    var orderedIds = computed(messageLookup, (lookup) => {
37
      var msgs = Object.keys(lookup).map(k => lookup[k])
38
      return sort(msgs).map(getKey)
39
    })
40
41
    var messages = map(orderedIds, (id) => {
42
      return messageLookup.get(id)
43
    })
44
45
    var result = {
46
      messages,
47
      lastId: computed(messages, (messages) => {
48
        var last = messages[messages.length - 1]
49
        if (last) {
50
          return last.key
51
        }
52
      }),
53
      rootId: computed(messages, (messages) => {
54
        if (branch && messages.length) {
55
          return messages[0].value.content.root
56
        } else {
57
          return rootId
58
        }
59
      }),
60
      branchId: computed(messages, (messages) => {
61
        if (branch) {
62
          return rootId
63
        }
64
      }),
65
      previousKey: function (msg) {
66
        return PreviousKey(result.messages, msg)
67
      }
68
    }
69
70
    result.sync = messageLookup.sync
71
72
    return result
73
  })
74
75
  function unboxIfNeeded () {
76
    return pull.map(function (msg) {
77
      if (msg.sync || (msg.value && typeof msg.value.content === 'object')) {
78
        return msg
79
      } else {
80
        return api.message.sync.unbox(msg)
81
      }
82
    })
83
  }
84
}
85
86
function getKey (msg) {
87
  return msg.key
88
}
89
90
function PreviousKey (collection, item) {
91
  return computed(collection, (c) => {
92
    var index = collection.indexOf(item)
93
    if (~index) {
94
      var previous = c[index - 1]
95
      if (previous) {
96
        return previous.key
97
      }
98
    }
99
  })
100
}
101