diff options
author | Joel Kronqvist <joel.h.kronqvist@gmail.com> | 2022-03-05 19:02:27 +0200 |
---|---|---|
committer | Joel Kronqvist <joel.h.kronqvist@gmail.com> | 2022-03-05 19:02:27 +0200 |
commit | 5d309ff52cd399a6b71968a6b9a70c8ac0b98981 (patch) | |
tree | 360f7eb50f956e2367ef38fa1fc6ac7ac5258042 /node_modules/w3c-hr-time/lib/calculate-clock-offset.js | |
parent | b500a50f1b97d93c98b36ed9a980f8188d648147 (diff) | |
download | LYLLRuoka-5d309ff52cd399a6b71968a6b9a70c8ac0b98981.tar.gz LYLLRuoka-5d309ff52cd399a6b71968a6b9a70c8ac0b98981.zip |
Added node_modules for the updating to work properly.
Diffstat (limited to 'node_modules/w3c-hr-time/lib/calculate-clock-offset.js')
-rw-r--r-- | node_modules/w3c-hr-time/lib/calculate-clock-offset.js | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/node_modules/w3c-hr-time/lib/calculate-clock-offset.js b/node_modules/w3c-hr-time/lib/calculate-clock-offset.js new file mode 100644 index 0000000..8659d30 --- /dev/null +++ b/node_modules/w3c-hr-time/lib/calculate-clock-offset.js @@ -0,0 +1,39 @@ +"use strict"; + +// This files implements the calculation of the offset between the global monotonic clock and UNIX time. This value is +// known as |t1| in the calculation of "time origin timestamp" in the spec. This value needs to be calculated once and +// can be used in all subsequent Performance instances. +// +// However, if the clock is not fast enough, the export is undefined to signify that we should use Date.now() to get the +// time origin timestamp with millisecond accuracy, per spec. + +const { getGlobalMonotonicClockMS } = require("./global-monotonic-clock"); +const clockIsAccurate = require("./clock-is-accurate"); + +// This function assumes the clock is accurate. +function calculateClockOffset() { + const start = Date.now(); + let cur = start; + // Limit the iterations, just in case we're running in an environment where Date.now() has been mocked and is + // constant. + for (let i = 0; i < 1e6 && cur === start; i++) { + cur = Date.now(); + } + + // At this point |cur| "just" became equal to the next millisecond -- the unseen digits after |cur| are approximately + // all 0, and |cur| is the closest to the actual value of the UNIX time. Now, get the current global monotonic clock + // value and do the remaining calculations. + + return cur - getGlobalMonotonicClockMS(); +} + +if (clockIsAccurate) { + // Warm up the function. + calculateClockOffset(); + calculateClockOffset(); + calculateClockOffset(); + + module.exports = calculateClockOffset; +} else { + module.exports = undefined; +} |