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// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build windows
package testing
import (
"errors"
"internal/syscall/windows"
"math/bits"
"syscall"
"time"
)
// isWindowsRetryable reports whether err is a Windows error code
// that may be fixed by retrying a failed filesystem operation.
func isWindowsRetryable(err error) bool {
for {
unwrapped := errors.Unwrap(err)
if unwrapped == nil {
break
}
err = unwrapped
}
if err == syscall.ERROR_ACCESS_DENIED {
return true // Observed in https://go.dev/issue/50051.
}
if err == windows.ERROR_SHARING_VIOLATION {
return true // Observed in https://go.dev/issue/51442.
}
return false
}
// highPrecisionTime represents a single point in time with query performance counter.
// time.Time on Windows has low system granularity, which is not suitable for
// measuring short time intervals.
//
// TODO: If Windows runtime implements high resolution timing then highPrecisionTime
// can be removed.
type highPrecisionTime struct {
now int64
}
// highPrecisionTimeNow returns high precision time for benchmarking.
func highPrecisionTimeNow() highPrecisionTime {
var t highPrecisionTime
// This should always succeed for Windows XP and above.
t.now = windows.QueryPerformanceCounter()
return t
}
func (a highPrecisionTime) sub(b highPrecisionTime) time.Duration {
delta := a.now - b.now
if queryPerformanceFrequency == 0 {
queryPerformanceFrequency = windows.QueryPerformanceFrequency()
}
hi, lo := bits.Mul64(uint64(delta), uint64(time.Second)/uint64(time.Nanosecond))
quo, _ := bits.Div64(hi, lo, uint64(queryPerformanceFrequency))
return time.Duration(quo)
}
var queryPerformanceFrequency int64
// highPrecisionTimeSince returns duration since a.
func highPrecisionTimeSince(a highPrecisionTime) time.Duration {
return highPrecisionTimeNow().sub(a)
}