...
Run Format

Source file src/time/internal_test.go

Documentation: time

  // Copyright 2011 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.
  
  package time
  
  func init() {
  	// force US/Pacific for time zone tests
  	ForceUSPacificForTesting()
  }
  
  var Interrupt = interrupt
  var DaysIn = daysIn
  
  func empty(arg interface{}, seq uintptr) {}
  
  // Test that a runtimeTimer with a duration so large it overflows
  // does not cause other timers to hang.
  //
  // This test has to be in internal_test.go since it fiddles with
  // unexported data structures.
  func CheckRuntimeTimerOverflow() {
  	// We manually create a runtimeTimer to bypass the overflow
  	// detection logic in NewTimer: we're testing the underlying
  	// runtime.addtimer function.
  	r := &runtimeTimer{
  		when: runtimeNano() + (1<<63 - 1),
  		f:    empty,
  		arg:  nil,
  	}
  	startTimer(r)
  
  	// Start a goroutine that should send on t.C right away.
  	t := NewTimer(1)
  
  	defer func() {
  		// Subsequent tests won't work correctly if we don't stop the
  		// overflow timer and kick the timer proc back into service.
  		//
  		// The timer proc is now sleeping and can only be awoken by
  		// adding a timer to the *beginning* of the heap. We can't
  		// wake it up by calling NewTimer since other tests may have
  		// left timers running that should have expired before ours.
  		// Instead we zero the overflow timer duration and start it
  		// once more.
  		stopTimer(r)
  		t.Stop()
  		r.when = 0
  		startTimer(r)
  	}()
  
  	// If the test fails, we will hang here until the timeout in the testing package
  	// fires, which is 10 minutes. It would be nice to catch the problem sooner,
  	// but there is no reliable way to guarantee that timerproc schedules without
  	// doing something involving timerproc itself. Previous failed attempts have
  	// tried calling runtime.Gosched and runtime.GC, but neither is reliable.
  	// So we fall back to hope: We hope we don't hang here.
  	<-t.C
  }
  

View as plain text