Fix bug: don't enqueue a process in the process-input-queue if it is

already in the queue.  Otherwise, it can easily get entered very many
times: if there is input waiting, and the editor is busy, the process
will be queued as often as the select code can run.

diff --git a/v7/src/edwin/process.scm b/v7/src/edwin/process.scm
index 8c1b8165ed86671bff36cc621887f59d2192be5c..01369b956c169c299e6a226eb2d4ee97531eb354 100644 (file)
--- a/v7/src/edwin/process.scm
+++ b/v7/src/edwin/process.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;    $Id: process.scm,v 1.50 1996/05/15 20:05:50 cph Exp $
+;;;    $Id: process.scm,v 1.51 1996/05/24 07:33:41 cph Exp $
 ;;;
 ;;;    Copyright (c) 1991-96 Massachusetts Institute of Technology
 ;;;
@@ -244,12 +244,13 @@ Initialized from the SHELL environment variable."
     (channel-descriptor-for-select channel)
     (current-thread)
     (lambda ()
-      (let ((queue process-input-queue)
-           (tail (list process)))
-       (if (null? (cdr queue))
-           (set-car! queue tail)
-           (set-cdr! (cdr queue) tail))
-       (set-cdr! queue tail))))))
+      (let ((queue process-input-queue))
+       (if (not (memq process (car queue)))
+           (let ((tail (list process)))
+             (if (null? (cdr queue))
+                 (set-car! queue tail)
+                 (set-cdr! (cdr queue) tail))
+             (set-cdr! queue tail))))))))
 
 (define (process-output-available?)
   (not (null? (car process-input-queue))))