(zilch core statusbar): small cleanups

core/src/statusbar.sld

@@ -10,6 +10,8 @@
     statusbar-logger)
 
   (begin
+    ; Creates a buffered port, which buffers up to one line (terminated by a newline character)
+    ; and calls redraw-status-bar after a write that prints a newline.
     (define (buffered-port mutex write-output-line redraw-status-bar close-this-port)
       (define line-buffer (make-bytevector 1024 0))
       (define line-buffer-location 0)
@@ -40,18 +42,23 @@
       (make-output-port (lambda (str) (mutex-lock! mutex) (write-data (string->utf8 str) 0)) close-this-port))
 
     (define (statusbar-logger out-port err-port print-logs)
+      ; Current status bar text
       (define status-bar "[0/0 builds, 0 running] ...")
       (define terminal-width 80)
       (define-values (rows cols) (terminal-size err-port))
       (when (> cols 0) (set! terminal-width cols))
 
       (define (terminal-width-thread-thunk handler)
-        (handler #t)
-        (mutex-lock! out-mutex)
+        ; Lock the output mutex whilst setting the terminal size.
         (define-values (rows cols) (terminal-size err-port))
+        (mutex-lock! out-mutex)
         (when (> cols 0) (set! terminal-width cols))
         (mutex-unlock! out-mutex)
+
+        ; Wait until the next SIGWINCH, then loop
+        (handler #t)
         (terminal-width-thread-thunk handler))
+
       (define terminal-width-thread (make-thread (lambda () (terminal-width-thread-thunk (make-signal-handler signal/winch)))))
 
       (define (draw-status-bar)
@@ -92,7 +99,7 @@
           (begin
             (set! last-activity-start-id #f)
             (set! last-activity-start (utf8->string (bytevector-copy buf start end)))
-            (set! need-redraw #t))))
+            (draw-status-bar))))
 
       (define (write-out-line buf start end)
         (unless need-redraw