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[JS + docs] improve std/monotimes module (#17103)

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flywind 2021-02-22 04:09:25 -06:00 • committed by GitHub
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2 changed files with 49 additions and 43 deletions
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40
lib/std/monotimes.nim
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@ -8,17 +8,21 @@
# #
##[ ##[
The ``std/monotimes`` module implements monotonic timestamps. A monotonic The `std/monotimes` module implements monotonic timestamps. A monotonic
timestamp represents the time that has passed since some system defined timestamp represents the time that has passed since some system defined
point in time. The monotonic timestamps are guaranteed to always increase, point in time. The monotonic timestamps are guaranteed to always increase,
meaning that that the following is guaranteed to work: meaning that that the following is guaranteed to work:
]##
runnableExamples:
import std/os
.. code-block:: nim
let a = getMonoTime() let a = getMonoTime()
# ... do some work sleep(10)
let b = getMonoTime() let b = getMonoTime()
assert a <= b assert a < b
##[
This is not guaranteed for the `times.Time` type! This means that the This is not guaranteed for the `times.Time` type! This means that the
`MonoTime` should be used when measuring durations of time with `MonoTime` should be used when measuring durations of time with
high precision. high precision.
@ -35,7 +39,7 @@
* `times module <times.html>`_ * `times module <times.html>`_
]## ]##
import times import std/times
type type
MonoTime* = object ## Represents a monotonic timestamp. MonoTime* = object ## Represents a monotonic timestamp.
@ -53,18 +57,16 @@ when defined(macosx):
when defined(js): when defined(js):
proc getJsTicks: float = proc getJsTicks: float =
## Returns ticks in the unit seconds ## Returns ticks in the unit seconds.
when defined(nodejs):
{.emit: """ {.emit: """
var isNode = typeof module !== 'undefined' && module.exports let process = require('process');
let time = process.hrtime();
if (isNode) { `result` = time[0] + time[1] / 1000000000;
var process = require('process');
var time = process.hrtime()
return time[0] + time[1] / 1000000000;
} else {
return window.performance.now() / 1000;
}
""".} """.}
else:
proc jsNow(): float {.importjs: "window.performance.now()".}
result = jsNow() / 1000
# Workaround for #6752. # Workaround for #6752.
{.push overflowChecks: off.} {.push overflowChecks: off.}
@ -75,7 +77,7 @@ when defined(js):
{.pop.} {.pop.}
elif defined(posix) and not defined(osx): elif defined(posix) and not defined(osx):
import posix import std/posix
elif defined(windows): elif defined(windows):
proc QueryPerformanceCounter(res: var uint64) {. proc QueryPerformanceCounter(res: var uint64) {.
@ -84,11 +86,11 @@ elif defined(windows):
importc: "QueryPerformanceFrequency", stdcall, dynlib: "kernel32".} importc: "QueryPerformanceFrequency", stdcall, dynlib: "kernel32".}
proc getMonoTime*(): MonoTime {.tags: [TimeEffect].} = proc getMonoTime*(): MonoTime {.tags: [TimeEffect].} =
## Get the current `MonoTime` timestamp. ## Returns the current `MonoTime` timestamp.
## ##
## When compiled with the JS backend and executed in a browser, ## When compiled with the JS backend and executed in a browser,
## this proc calls `window.performance.now()`, which is not supported by ## this proc calls `window.performance.now()`.
## older browsers. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now) ## See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now)
## for more information. ## for more information.
when defined(js): when defined(js):
let ticks = getJsTicks() let ticks = getJsTicks()

6
tests/stdlib/tmonotimes.nim
View file

@ -1,4 +1,8 @@
import std/monotimes, times discard """
targets: "c js"
"""
import std/[monotimes, times]
let d = initDuration(nanoseconds = 10) let d = initDuration(nanoseconds = 10)
let t1 = getMonoTime() let t1 = getMonoTime()