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.
Test: status_test.go
Change-Id: I555ad21a31a2c924ab0ca681e0c8f00df42a370a
diff --git a/ui/terminal/smart_status.go b/ui/terminal/smart_status.go
index 8fa9eff..999a2d0 100644
--- a/ui/terminal/smart_status.go
+++ b/ui/terminal/smart_status.go
@@ -17,8 +17,11 @@
import (
"fmt"
"io"
+ "os"
+ "os/signal"
"strings"
"sync"
+ "syscall"
"android/soong/ui/status"
)
@@ -30,18 +33,29 @@
lock sync.Mutex
haveBlankLine bool
+
+ termWidth int
+ sigwinch chan os.Signal
}
// 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 +115,8 @@
s.lock.Lock()
defer s.lock.Unlock()
+ s.stopSigwinch()
+
s.requestLine()
}
@@ -137,16 +153,8 @@
// 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 +164,35 @@
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()
+ }
+ }()
+}
+
+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
+ }
+}