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denoland-deno/cli/ops/performance.rs
2019-08-26 08:50:21 -04:00

30 lines
1 KiB
Rust

// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
use super::dispatch_json::{JsonOp, Value};
use crate::state::ThreadSafeState;
use deno::*;
// Returns a milliseconds and nanoseconds subsec
// since the start time of the deno runtime.
// If the High precision flag is not set, the
// nanoseconds are rounded on 2ms.
pub fn op_now(
state: &ThreadSafeState,
_args: Value,
_zero_copy: Option<PinnedBuf>,
) -> Result<JsonOp, ErrBox> {
let seconds = state.start_time.elapsed().as_secs();
let mut subsec_nanos = state.start_time.elapsed().subsec_nanos();
let reduced_time_precision = 2_000_000; // 2ms in nanoseconds
// If the permission is not enabled
// Round the nano result on 2 milliseconds
// see: https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp#Reduced_time_precision
if !state.permissions.allows_hrtime() {
subsec_nanos -= subsec_nanos % reduced_time_precision
}
Ok(JsonOp::Sync(json!({
"seconds": seconds,
"subsecNanos": subsec_nanos,
})))
}