git ssb

1
2
var keys = exports.keys =
3
function (object) {
4
  return values(Object.keys(object))
5
}
6
7
var once = exports.once =
8
function (value) {
9
  return function (abort, cb) {
10
    if(abort) return cb(abort)
11
    if(value != null) {
12
      var _value = value; value = null
13
      cb(null, _value)
14
    } else
15
      cb(true)
16
  }
17
}
18
19
var values = exports.values = exports.readArray =
20
function (array) {
21
  if(!Array.isArray(array))
22
    array = Object.keys(array).map(function (k) {
23
      return array[k]
24
    })
25
  var i = 0
26
  return function (end, cb) {
27
    if(end)
28
      return cb && cb(end)  
29
    cb(i >= array.length || null, array[i++])
30
  }
31
}
32
33
34
var count = exports.count = 
35
function (max) {
36
  var i = 0; max = max || Infinity
37
  return function (end, cb) {
38
    if(end) return cb && cb(end)
39
    if(i > max)
40
      return cb(true)
41
    cb(null, i++)
42
  }
43
}
44
45
var infinite = exports.infinite = 
46
function (generate) {
47
  generate = generate || Math.random
48
  return function (end, cb) {
49
    if(end) return cb && cb(end)
50
    return cb(null, generate())
51
  }
52
}
53
54
var defer = exports.defer = function () {
55
  var _read, cbs = [], _end
56
57
  var read = function (end, cb) {
58
    if(!_read) {
59
      _end = end
60
      cbs.push(cb)
61
    } 
62
    else _read(end, cb)
63
  }
64
  read.resolve = function (read) {
65
    if(_read) throw new Error('already resolved')
66
    _read = read
67
    if(!_read) throw new Error('no read cannot resolve!' + _read)
68
    while(cbs.length)
69
      _read(_end, cbs.shift())
70
  }
71
  read.abort = function(err) {
72
    read.resolve(function (_, cb) {
73
      cb(err || true)
74
    })
75
  }
76
  return read
77
}
78
79
var empty = exports.empty = function () {
80
  return function (abort, cb) {
81
    cb(true)
82
  }
83
}
84
85
var depthFirst = exports.depthFirst =
86
function (start, createStream) {
87
  var reads = []
88
89
  reads.unshift(once(start))
90
91
  return function next (end, cb) {
92
    if(!reads.length)
93
      return cb(true)
94
    reads[0](end, function (end, data) {
95
      if(end) {
96
        //if this stream has ended, go to the next queue
97
        reads.shift()
98
        return next(null, cb)
99
      }
100
      reads.unshift(createStream(data))
101
      cb(end, data)
102
    })
103
  }
104
}
105
//width first is just like depth first,
106
//but push each new stream onto the end of the queue
107
var widthFirst = exports.widthFirst = 
108
function (start, createStream) {
109
  var reads = []
110
111
  reads.push(once(start))
112
113
  return function next (end, cb) {
114
    if(!reads.length)
115
      return cb(true)
116
    reads[0](end, function (end, data) {
117
      if(end) {
118
        reads.shift()
119
        return next(null, cb)
120
      }
121
      reads.push(createStream(data))
122
      cb(end, data)
123
    })
124
  }
125
}
126
127
//this came out different to the first (strm)
128
//attempt at leafFirst, but it's still a valid
129
//topological sort.
130
var leafFirst = exports.leafFirst = 
131
function (start, createStream) {
132
  var reads = []
133
  var output = []
134
  reads.push(once(start))
135
  
136
  return function next (end, cb) {
137
    reads[0](end, function (end, data) {
138
      if(end) {
139
        reads.shift()
140
        if(!output.length)
141
          return cb(true)
142
        return cb(null, output.shift())
143
      }
144
      reads.unshift(createStream(data))
145
      output.unshift(data)
146
      next(null, cb)
147
    })
148
  }
149
}
150
151