async status line

2 files changed, 49 insertions, 3 deletions

diff --git a/go/src/cow-dedupe/dedupe.go b/go/src/cow-dedupe/dedupe.go
index 9fee970..62fd85d 100644
--- a/go/src/cow-dedupe/dedupe.go
+++ b/go/src/cow-dedupe/dedupe.go
@@ -10,6 +10,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"time"
 
 	"lib/statusline"
 )
@@ -34,7 +35,7 @@ func getFiemaps(paths []string) map[string][]string {
 
 	ret := map[string][]string{}
 
-	sl := statusline.NewStatusLine(os.Stderr)
+	sl := statusline.NewAsyncStatusLine(os.Stderr, time.Second/2)
 	cnt := 0
 	sl.Put("Mapping extents...")
 
@@ -77,7 +78,7 @@ func getFiemaps(paths []string) map[string][]string {
 func getChecksums(paths []string) map[string][]string {
 	ret := map[string][]string{}
 
-	sl := statusline.NewStatusLine(os.Stderr)
+	sl := statusline.NewAsyncStatusLine(os.Stderr, time.Second/2)
 	cnt := 0
 	sl.Put(fmt.Sprintf("Generating checksums for files... %d/%d\n", cnt, len(paths)))
 
@@ -128,7 +129,7 @@ func getChecksums(paths []string) map[string][]string {
 func main() {
 	// we have low parallelism, don't let syscalls fan-out weird
 	// on many-core systems
-	runtime.GOMAXPROCS(1)
+	runtime.GOMAXPROCS(2)
 
 	fiemap2filenames := getFiemaps(os.Args[1:])
 
diff --git a/go/src/lib/statusline/async.go b/go/src/lib/statusline/async.go
new file mode 100644
index 0000000..32c9a2b
--- /dev/null
+++ b/go/src/lib/statusline/async.go
@@ -0,0 +1,45 @@
+package statusline
+
+import (
+	"io"
+	"time"
+)
+
+type AsyncStatusLine struct {
+	lines chan string
+	end   chan struct{}
+}
+
+func NewAsyncStatusLine(out io.Writer, d time.Duration) *AsyncStatusLine {
+	ret := &AsyncStatusLine{
+		lines: make(chan string),
+		end:   make(chan struct{}),
+	}
+	go func() {
+		sl := NewStatusLine(out)
+		ticker := time.NewTicker(d)
+		var line string
+		for {
+			select {
+			case <-ticker.C:
+				sl.Put(line)
+			case l := <-ret.lines:
+				line = l
+			case <-ret.end:
+				sl.End()
+				ticker.Stop()
+			}
+		}
+	}()
+	return ret
+}
+
+func (sl *AsyncStatusLine) Put(line string) {
+	sl.lines <- line
+}
+
+func (sl *AsyncStatusLine) End() {
+	sl.end <- struct{}{}
+	close(sl.lines)
+	close(sl.end)
+}