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import std/tables
import monoucha/quickjs
import monoucha/javascript
import monoucha/jsutils
import monoucha/jsopaque
import monoucha/tojs
import types/opt
type
PromiseState = enum
psPending, psFulfilled, psRejected
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 newPromise*[T](): Promise[T] =
return Promise[T]()
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 = psFulfilled
promise = promise.next
if promise == nil:
break
promise.next = nil
proc resolve*[T](promise: Promise[T]; res: T) =
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()
proc newResolvedPromise*(): EmptyPromise =
let res = EmptyPromise()
res.resolve()
return res
func empty*(map: PromiseMap): bool =
map.tab.len == 0
proc then*(promise: EmptyPromise; cb: (proc())): EmptyPromise {.discardable.} =
promise.cb = cb
promise.next = EmptyPromise()
if promise.state == psFulfilled:
promise.resolve()
return promise.next
proc then*(promise: EmptyPromise; cb: (proc(): EmptyPromise)): EmptyPromise
{.discardable.} =
let next = EmptyPromise()
promise.then(proc() =
var p2 = cb()
if p2 != nil:
p2.then(proc() =
next.resolve())
else:
next.resolve())
return next
proc then*[T](promise: Promise[T]; cb: (proc(x: T))): EmptyPromise
{.discardable.} =
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.} =
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.} =
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](promise: EmptyPromise; cb: (proc(): T)): Promise[T]
{.discardable.} =
let next = Promise[T]()
promise.then(proc() =
next.res = cb()
next.resolve())
return next
proc then*[T, U](promise: Promise[T]; cb: (proc(x: T): U)): Promise[U]
{.discardable.} =
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.} =
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.} =
let next = Promise[Opt[U]]()
promise.then(proc(x: T) =
let p2 = cb(x)
if p2.isSome:
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
# * Promise is converted to a JS promise which will be resolved when the Nim
# promise is resolved.
proc promiseThenCallback(ctx: JSContext; this_val: JSValue; argc: cint;
argv: ptr UncheckedArray[JSValue]; magic: cint;
func_data: ptr UncheckedArray[JSValue]): JSValue {.cdecl.} =
let fun = func_data[0]
let op = JS_GetOpaque(fun, JS_GetClassID(fun))
if op != nil:
let p = cast[EmptyPromise](op)
p.resolve()
GC_unref(p)
JS_SetOpaque(fun, nil)
return JS_UNDEFINED
proc fromJS*(ctx: JSContext; val: JSValue; res: var EmptyPromise): Opt[void] =
if not JS_IsObject(val):
JS_ThrowTypeError(ctx, "value is not an object")
return err()
res = EmptyPromise()
GC_ref(res)
let tmp = JS_NewObject(ctx)
JS_SetOpaque(tmp, cast[pointer](res))
let fun = JS_NewCFunctionData(ctx, promiseThenCallback, 0, 0, 1,
tmp.toJSValueArray())
JS_FreeValue(ctx, tmp)
let val = JS_Invoke(ctx, val, ctx.getOpaque().strRefs[jstThen], 1,
fun.toJSValueArray())
JS_FreeValue(ctx, fun)
if JS_IsException(val):
JS_FreeValue(ctx, val)
GC_unref(res)
res = nil
return err()
JS_FreeValue(ctx, val)
return ok()
proc toJS*(ctx: JSContext; promise: EmptyPromise): JSValue =
if promise == nil:
return JS_NULL
var resolvingFuncs: array[2, JSValue]
let jsPromise = JS_NewPromiseCapability(ctx, resolvingFuncs.toJSValueArray())
if JS_IsException(jsPromise):
return JS_EXCEPTION
promise.then(proc() =
let res = JS_Call(ctx, resolvingFuncs[0], JS_UNDEFINED, 0, nil)
JS_FreeValue(ctx, res)
JS_FreeValue(ctx, resolvingFuncs[0])
JS_FreeValue(ctx, resolvingFuncs[1]))
return jsPromise
proc toJS*[T](ctx: JSContext; promise: Promise[T]): JSValue =
if promise == nil:
return JS_NULL
var resolvingFuncs: array[2, JSValue]
let jsPromise = JS_NewPromiseCapability(ctx, resolvingFuncs.toJSValueArray())
if JS_IsException(jsPromise):
return JS_EXCEPTION
promise.then(proc(x: T) =
let x = toJS(ctx, x)
let res = JS_Call(ctx, resolvingFuncs[0], JS_UNDEFINED, 1,
x.toJSValueArray())
JS_FreeValue(ctx, res)
JS_FreeValue(ctx, x)
JS_FreeValue(ctx, resolvingFuncs[0])
JS_FreeValue(ctx, resolvingFuncs[1]))
return jsPromise
proc toJS*[T, E](ctx: JSContext; promise: Promise[Result[T, E]]): JSValue =
if promise == nil:
return JS_NULL
var resolvingFuncs: array[2, JSValue]
let jsPromise = JS_NewPromiseCapability(ctx, resolvingFuncs.toJSValueArray())
if JS_IsException(jsPromise):
return JS_EXCEPTION
promise.then(proc(x: Result[T, E]) =
if x.isSome:
let x = when T is void:
JS_UNDEFINED
else:
toJS(ctx, x.get)
let res = JS_Call(ctx, resolvingFuncs[0], JS_UNDEFINED, 1,
x.toJSValueArray())
JS_FreeValue(ctx, res)
JS_FreeValue(ctx, x)
else: # err
let x = when E is void:
JS_UNDEFINED
else:
toJS(ctx, x.error)
let res = JS_Call(ctx, resolvingFuncs[1], JS_UNDEFINED, 1,
x.toJSValueArray())
JS_FreeValue(ctx, res)
JS_FreeValue(ctx, x)
JS_FreeValue(ctx, resolvingFuncs[0])
JS_FreeValue(ctx, resolvingFuncs[1]))
return jsPromise
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