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
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
import tables
import utils/opt
type
PromiseState* = enum
PROMISE_PENDING, PROMISE_FULFILLED, PROMISE_REJECTED
EmptyPromise* = ref object of RootObj
cb: (proc())
next: EmptyPromise
opaque: pointer
state*: PromiseState
Promise*[T] = ref object of EmptyPromise
res: T
get: GetValueProc[T]
GetValueProc[T] = (proc(opaque: pointer, res: var T))
PromiseMap* = object
tab: Table[int, EmptyPromise]
opaque*: pointer
proc newPromiseMap*(opaque: pointer): PromiseMap =
return PromiseMap(
opaque: opaque
)
proc addPromise*[T](map: var PromiseMap, id: int, get: GetValueProc[T]): Promise[T] =
let promise = Promise[T](get: get, opaque: map.opaque)
map.tab[id] = promise
return promise
proc addEmptyPromise*(map: var PromiseMap, id: int): EmptyPromise =
let promise = EmptyPromise(opaque: map.opaque)
map.tab[id] = promise
return promise
proc resolve*(promise: EmptyPromise) =
var promise = promise
while true:
if promise.cb != nil:
promise.cb()
promise.cb = nil
promise.state = PROMISE_FULFILLED
promise = promise.next
if promise == nil:
break
promise.next = nil
proc resolve*[T](promise: Promise[T], res: T) =
if promise.cb != nil:
if promise.get != nil:
promise.get(promise.opaque, promise.res)
promise.get = nil
promise.res = res
promise.resolve()
proc resolve*(map: var PromiseMap, promiseid: int) =
var promise: EmptyPromise
if map.tab.pop(promiseid, promise):
promise.resolve()
func empty*(map: PromiseMap): bool =
map.tab.len == 0
proc then*(promise: EmptyPromise, cb: (proc())): EmptyPromise {.discardable.} =
if promise == nil:
doAssert false
return
promise.cb = cb
promise.next = EmptyPromise()
if promise.state == PROMISE_FULFILLED:
promise.resolve()
return promise.next
proc then*[T](promise: Promise[T], cb: (proc(x: T))): EmptyPromise {.discardable.} =
doAssert promise != nil
return promise.then(proc() =
if promise.get != nil:
promise.get(promise.opaque, promise.res)
promise.get = nil
cb(promise.res))
proc then*[T](promise: EmptyPromise, cb: (proc(): Promise[T])): Promise[T] {.discardable.} =
doAssert promise != nil
let next = Promise[T]()
promise.then(proc() =
var p2 = cb()
if p2 != nil:
p2.then(proc(x: T) =
next.res = x
next.resolve())
else:
next.resolve())
return next
proc then*[T](promise: Promise[T], cb: (proc(x: T): EmptyPromise)): EmptyPromise {.discardable.} =
doAssert promise != nil
let next = EmptyPromise()
promise.then(proc(x: T) =
let p2 = cb(x)
if p2 != nil:
p2.then(proc() =
next.resolve())
else:
next.resolve())
return next
proc then*[T, U](promise: Promise[T], cb: (proc(x: T): U)): Promise[U] {.discardable.} =
doAssert promise != nil
let next = Promise[U]()
promise.then(proc(x: T) =
next.res = cb(x)
next.resolve())
return next
proc then*[T, U](promise: Promise[T], cb: (proc(x: T): Promise[U])): Promise[U] {.discardable.} =
doAssert promise != nil
let next = Promise[U]()
promise.then(proc(x: T) =
let p2 = cb(x)
if p2 != nil:
p2.then(proc(y: U) =
next.res = y
next.resolve())
else:
next.resolve())
return next
proc then*[T, U](promise: Promise[T], cb: (proc(x: T): Opt[Promise[U]])):
Promise[Opt[U]] {.discardable.} =
doAssert promise != nil
let next = Promise[Opt[U]]()
promise.then(proc(x: T) =
let p2 = cb(x)
if p2.isOk:
p2.get.then(proc(y: U) =
next.res = opt(y)
next.resolve())
else:
next.resolve())
return next
proc all*(promises: seq[EmptyPromise]): EmptyPromise =
let res = EmptyPromise()
var i = 0
for promise in promises:
promise.then(proc() =
inc i
if i == promises.len:
res.resolve())
if promises.len == 0:
res.resolve()
return res
|