Miscellaneous tq-related fixes.

* lisp/emacs-lisp/tq.el: Small grammar fix in comments.
  (tq-enqueue): Check for existence of queue rather than the head queue
  item's question, which was a no-op.
  (tq-filter, tq-process-buffer): Make sure the process buffer exists
  before making it the current buffer.

* lispref/processes.texi (Transaction Queues): Remove stray quote
  character.

Revision: emacs@sv.gnu.org/emacs--devo--0--patch-411
Creator:  Michael Olson <mwolson@gnu.org>

2 files changed, 40 insertions, 28 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 2d203896066..187f2ff3fae 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2006-08-27  Michael Olson  <mwolson@gnu.org>
+
+        * emacs-lisp/tq.el: Small grammar fix in comments.
+        (tq-enqueue): Check for existence of queue rather than the
+        head queue item's question, which was a no-op.
+        (tq-filter, tq-process-buffer): Make sure the process buffer
+        exists before making it the current buffer.
+
 2006-08-27  YAMAMOTO Mitsuharu  <mituharu@math.s.chiba-u.ac.jp>
 
         * term/mac-win.el (mac-apple-event-map): Rename hicommand to hi-command.
diff --git a/lisp/emacs-lisp/tq.el b/lisp/emacs-lisp/tq.el
index 2126d7663fc..1e1e143f0f0 100644
--- a/lisp/emacs-lisp/tq.el
+++ b/lisp/emacs-lisp/tq.el
@@ -66,7 +66,7 @@
 ;; regexp: regular expression that matches the end of a response from
 ;; the process
 (defun tq-queue-head-regexp   (tq) (car (cdr (car (tq-queue tq)))))
-;; closure: additional data to pass to function
+;; closure: additional data to pass to the function
 (defun tq-queue-head-closure  (tq) (car (cdr (cdr (car (tq-queue tq))))))
 ;; fn: function to call upon receiving a complete response from the
 ;; process
@@ -119,7 +119,7 @@ If DELAY-QUESTION is non-nil, delay sending this question until
 the process has finished replying to any previous questions.
 This produces more reliable results with some processes."
   (let ((sendp (or (not delay-question)
-                   (not (tq-queue-head-question tq)))))
+                   (not (tq-queue tq)))))
     (tq-queue-add tq (unless sendp question) regexp closure fn)
     (when sendp
       (process-send-string (tq-process tq) question))))
@@ -131,35 +131,39 @@ This produces more reliable results with some processes."
 
 (defun tq-filter (tq string)
   "Append STRING to the TQ's buffer; then process the new data."
-  (with-current-buffer (tq-buffer tq)
-    (goto-char (point-max))
-    (insert string)
-    (tq-process-buffer tq)))
+  (let ((buffer (tq-buffer tq)))
+    (when (buffer-live-p buffer)
+      (with-current-buffer buffer
+        (goto-char (point-max))
+        (insert string)
+        (tq-process-buffer tq)))))
 
 (defun tq-process-buffer (tq)
   "Check TQ's buffer for the regexp at the head of the queue."
-  (set-buffer (tq-buffer tq))
-  (if (= 0 (buffer-size)) ()
-    (if (tq-queue-empty tq)
-        (let ((buf (generate-new-buffer "*spurious*")))
-          (copy-to-buffer buf (point-min) (point-max))
-          (delete-region (point-min) (point))
-          (pop-to-buffer buf nil)
-          (error "Spurious communication from process %s, see buffer %s"
-                 (process-name (tq-process tq))
-                 (buffer-name buf)))
-      (goto-char (point-min))
-      (if (re-search-forward (tq-queue-head-regexp tq) nil t)
-          (let ((answer (buffer-substring (point-min) (point))))
-            (delete-region (point-min) (point))
-            (unwind-protect
-                (condition-case nil
-                    (funcall (tq-queue-head-fn tq)
-                             (tq-queue-head-closure tq)
-                             answer)
-                  (error nil))
-              (tq-queue-pop tq))
-            (tq-process-buffer tq))))))
+  (let ((buffer (tq-buffer tq)))
+    (when (buffer-live-p buffer)
+      (set-buffer buffer)
+      (if (= 0 (buffer-size)) ()
+        (if (tq-queue-empty tq)
+            (let ((buf (generate-new-buffer "*spurious*")))
+              (copy-to-buffer buf (point-min) (point-max))
+              (delete-region (point-min) (point))
+              (pop-to-buffer buf nil)
+              (error "Spurious communication from process %s, see buffer %s"
+                     (process-name (tq-process tq))
+                     (buffer-name buf)))
+          (goto-char (point-min))
+          (if (re-search-forward (tq-queue-head-regexp tq) nil t)
+              (let ((answer (buffer-substring (point-min) (point))))
+                (delete-region (point-min) (point))
+                (unwind-protect
+                    (condition-case nil
+                        (funcall (tq-queue-head-fn tq)
+                                 (tq-queue-head-closure tq)
+                                 answer)
+                      (error nil))
+                  (tq-queue-pop tq))
+                (tq-process-buffer tq))))))))
 
 (provide 'tq)