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Commit 4355ee64 authored by Colin Cross's avatar Colin Cross
Browse files

Use SIGWINCH to update terminal size 

Instead of reading the terminal size on every status update, register
for SIGWINCH to read and store the size when it changes.

This reapplies I555ad21a31a2c924ab0ca681e0c8f00df42a370a with a fix
for a race condition in TestSmartStatusOutputWidthChange.

Test: status_test.go
Change-Id: If342cb4cc8e4ed57af9e3bb417758348c9c41247
parent e77a5733

ui/terminal/smart_status.go

+55 −11
Original line number Diff line number Diff line
@@ -17,8 +17,11 @@ package terminal 
import (

	"fmt"

	"io"

	"os"

	"os/signal"

	"strings"

	"sync"

	"syscall"



	"android/soong/ui/status"

)
@@ -30,18 +33,30 @@ type smartStatusOutput struct { 
	lock sync.Mutex



	haveBlankLine bool



	termWidth       int

	sigwinch        chan os.Signal

	sigwinchHandled chan bool

}



// NewSmartStatusOutput returns a StatusOutput that represents the

// current build status similarly to Ninja's built-in terminal

// output.

func NewSmartStatusOutput(w io.Writer, formatter formatter) status.StatusOutput {

	return &smartStatusOutput{

	s := &smartStatusOutput{

		writer:    w,

		formatter: formatter,



		haveBlankLine: true,



		sigwinch: make(chan os.Signal),

	}



	s.updateTermSize()



	s.startSigwinch()



	return s

}



func (s *smartStatusOutput) Message(level status.MsgLevel, message string) {
@@ -101,6 +116,8 @@ func (s *smartStatusOutput) Flush() { 
	s.lock.Lock()

	defer s.lock.Unlock()



	s.stopSigwinch()



	s.requestLine()

}
@@ -137,16 +154,8 @@ func (s *smartStatusOutput) statusLine(str string) { 


	// Limit line width to the terminal width, otherwise we'll wrap onto

	// another line and we won't delete the previous line.

	//

	// Run this on every line in case the window has been resized while

	// we're printing. This could be optimized to only re-run when we get

	// SIGWINCH if it ever becomes too time consuming.

	if max, ok := termWidth(s.writer); ok {

		if len(str) > max {

			// TODO: Just do a max. Ninja elides the middle, but that's

			// more complicated and these lines aren't that important.

			str = str[:max]

		}

	if s.termWidth > 0 {

		str = s.elide(str)

	}



	// Move to the beginning on the line, turn on bold, print the output,
@@ -156,3 +165,38 @@ func (s *smartStatusOutput) statusLine(str string) { 
	fmt.Fprint(s.writer, start, str, end)

	s.haveBlankLine = false

}



func (s *smartStatusOutput) elide(str string) string {

	if len(str) > s.termWidth {

		// TODO: Just do a max. Ninja elides the middle, but that's

		// more complicated and these lines aren't that important.

		str = str[:s.termWidth]

	}



	return str

}



func (s *smartStatusOutput) startSigwinch() {

	signal.Notify(s.sigwinch, syscall.SIGWINCH)

	go func() {

		for _ = range s.sigwinch {

			s.lock.Lock()

			s.updateTermSize()

			s.lock.Unlock()

			if s.sigwinchHandled != nil {

				s.sigwinchHandled <- true

			}

		}

	}()

}



func (s *smartStatusOutput) stopSigwinch() {

	signal.Stop(s.sigwinch)

	close(s.sigwinch)

}



func (s *smartStatusOutput) updateTermSize() {

	if w, ok := termWidth(s.writer); ok {

		s.termWidth = w

	}

}

ui/terminal/status_test.go

+6 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ package terminal 
import (

	"bytes"

	"fmt"

	"syscall"

	"testing"



	"android/soong/ui/status"
@@ -252,6 +253,8 @@ func actionWithOuptutWithAnsiCodes(stat status.StatusOutput) { 
func TestSmartStatusOutputWidthChange(t *testing.T) {

	smart := &fakeSmartTerminal{termWidth: 40}

	stat := NewStatusOutput(smart, "", false)

	smartStat := stat.(*smartStatusOutput)

	smartStat.sigwinchHandled = make(chan bool)



	runner := newRunner(stat, 2)
@@ -260,6 +263,9 @@ func TestSmartStatusOutputWidthChange(t *testing.T) { 


	runner.startAction(action)

	smart.termWidth = 30

	// Fake a SIGWINCH

	smartStat.sigwinch <- syscall.SIGWINCH

	<-smartStat.sigwinchHandled

	runner.finishAction(result)



	stat.Flush()