From ff2443f496cbf7f648b84a78e468dc3f130c37f2 Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Thu, 29 Apr 2021 14:14:58 +0300
Subject: [PATCH] Simpler junkless statusline clearing

---
 doc/news.texi |  3 +++
 log.go        | 25 ++++++++++++-------------
 status.go     |  3 ++-
 3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/doc/news.texi b/doc/news.texi
index 6d5baba..0c29352 100644
--- a/doc/news.texi
+++ b/doc/news.texi
@@ -7,6 +7,9 @@
 @item
     Fixed proper @option{-xx} and @env{REDO_TRACE} workability, that
     previously was not applied to all targets.
+@item
+    Simpler statusline cleaning function, does not leading to whitespace
+    junk after long lines.
 @item
     Updated dependant libraries.
 @end itemize
diff --git a/log.go b/log.go
index 703f198..f4248de 100644
--- a/log.go
+++ b/log.go
@@ -68,8 +68,9 @@ var (
 	flagLogPid     = flag.Bool("log-pid", false, fmt.Sprintf("append PIDs (%s=1)", EnvLogPid))
 	flagLogJS      = flag.Bool("log-js", false, fmt.Sprintf("enable jobserver messages logging (%s=1)", EnvLogJS))
 
-	LogMutex   sync.Mutex
-	LogLenPrev int
+	LogMutex     sync.Mutex
+	KeyEraseLine string
+	LogWasStatus bool
 )
 
 func init() {
@@ -83,15 +84,12 @@ func init() {
 	CWarn = string(t.Escape.Magenta)
 	CJS = string(t.Escape.White)
 	CReset = string(t.Escape.Reset)
+	KeyEraseLine = fmt.Sprintf("%s[K", CReset[0:1])
 }
 
-func fillUpToTermSize(s, end string) string {
-	sLen := len(s)
-	if sLen < LogLenPrev {
-		s += strings.Repeat(" ", LogLenPrev-sLen)
-		LogLenPrev = sLen
-	} else {
-		LogLenPrev = sLen
+func erasedStatus(s, end string) string {
+	if LogWasStatus {
+		s += KeyEraseLine
 	}
 	return s + end
 }
@@ -103,10 +101,10 @@ func trace(level, format string, args ...interface{}) {
 	}
 	switch level {
 	case CNone:
+		p = StderrPrefix + p + fmt.Sprintf(format, args...)
 		LogMutex.Lock()
-		os.Stderr.WriteString(fillUpToTermSize(
-			StderrPrefix+p+fmt.Sprintf(format, args...), "\n",
-		))
+		os.Stderr.WriteString(erasedStatus(p, "\n"))
+		LogWasStatus = false
 		LogMutex.Unlock()
 		return
 	case CDebug:
@@ -142,7 +140,8 @@ func trace(level, format string, args ...interface{}) {
 	msg := fmt.Sprintf(format, args...)
 	msg = StderrPrefix + colourize(level, p+strings.Repeat(". ", Level)+msg)
 	LogMutex.Lock()
-	os.Stderr.WriteString(fillUpToTermSize(msg, "\n"))
+	os.Stderr.WriteString(erasedStatus(msg, "\n"))
+	LogWasStatus = false
 	LogMutex.Unlock()
 }
 
diff --git a/status.go b/status.go
index e6c9b31..7b45905 100644
--- a/status.go
+++ b/status.go
@@ -97,7 +97,8 @@ func statusInit() {
 				)
 			}
 			LogMutex.Lock()
-			os.Stderr.WriteString(fillUpToTermSize(out, "\r"))
+			os.Stderr.WriteString(erasedStatus(out, "\r"))
+			LogWasStatus = true
 			LogMutex.Unlock()
 		}
 	}()
-- 
2.44.0