Fix server.go

server.go processed Typesript output incorrectly when multiple
lines are concatenated together.

Change-Id: Id2af52df8edf702214aeeab1bae0242d3077c616

polygerrit-ui/server.go

@@ -527,6 +527,7 @@ var (
 )
 
 type typescriptLogWriter struct {
+	unfinishedLine string
 	logger         *log.Logger
 	// when WaitGroup counter is 0 the compilation is complete
 	compilationDoneWaiter *sync.WaitGroup
@@ -534,13 +535,30 @@ type typescriptLogWriter struct {
 
 func newTypescriptLogWriter(compilationCompleteWaiter *sync.WaitGroup) *typescriptLogWriter {
 	return &typescriptLogWriter{
+		unfinishedLine:        "",
 		logger:                log.New(log.Writer(), "TSC - ", log.Flags()),
 		compilationDoneWaiter: compilationCompleteWaiter,
 	}
 }
 
 func (lw typescriptLogWriter) Write(p []byte) (n int, err error) {
-	text := strings.TrimSpace(string(p))
+	// The input p can contain several lines and/or the partial line
+	// Code splits the input by EOL marker (\n) and stores the unfinished line
+	// for the next call to Write.
+	partialText := lw.unfinishedLine + string(p)
+	lines := strings.Split(partialText, "\n")
+	fullLines := lines
+	if strings.HasSuffix(partialText, "\n") {
+		lw.unfinishedLine = ""
+	} else {
+		fullLines = lines[:len(lines)-1]
+		lw.unfinishedLine = lines[len(lines)-1]
+	}
+	for _, fullLine := range fullLines {
+		text := strings.TrimSpace(fullLine)
+		if text == "" {
+			continue
+		}
 		if strings.HasSuffix(text, tsFileChangeDetectedMsg) ||
 			strings.HasSuffix(text, tsStartingCompilation) {
 			lw.compilationDoneWaiter.Add(1)
@@ -556,9 +574,9 @@ func (lw typescriptLogWriter) Write(p []byte) (n int, err error) {
 				time.Sleep(waitForNextChangeInterval)
 				lw.compilationDoneWaiter.Add(-1)
 			}()
-
 		}
 		lw.logger.Print(text)
+	}
 	return len(p), nil
 }