gud.el: long completion lists

[Nick Roberts]

The problem:

  If there are a large number of GDB completions in GUD this can lock up Emacs
  for an unreasonable amount of time e.g when debugging Emacs with M-x gdb try:

  (gdb) b <TAB>   (note the space between b and TAB)

  If you then press C-g all the completions start to spill out into the
  GUD buffer.

  From the command line GDB uses readline and when there are a large number of
  completions (over 100) it asks if the user wishes to proceed. For Emacs:

  (gdb) b <TAB>
  Display all 10513 possibilities? (y or n)

  Completion with GDB in Emacs is a bit awkward and doesn't use readline but
  the special GDB command "complete" with gud-gdb-complete-command.

The patch:

  So that there are no ambiguities - this is not a "proper" patch but it does
  show what I'm trying to do. It only works with "gdb --fullname", and not
  perfectly.

Can anybody do any better?

Nick

*** /home/nick/emacs/lisp/progmodes/gud.el.~1.39.~      2005-05-28 
08:46:11.000000000 +1200
--- /home/nick/emacs/lisp/progmodes/gud.el      2005-05-31 16:14:06.000000000 
+1200
***************
*** 606,611 ****
--- 606,613 ----
  ;; The completion list is constructed by the process filter.
  (defvar gud-gdb-fetched-lines)
  
+ (defvar gud-gdb-items 0)
+ 
  (defvar gud-comint-buffer nil)
  
  (defun gud-gdb-complete-command ()
***************
*** 654,660 ****
  
  ;; The completion process filter is installed temporarily to slurp the
  ;; output of GDB up to the next prompt and build the completion list.
! (defun gud-gdb-fetch-lines-filter (string filter)
    "Filter used to read the list of lines output by a command.
  STRING is the output to filter.
  It is passed through FILTER before we look at it."
--- 656,662 ----
  
  ;; The completion process filter is installed temporarily to slurp the
  ;; output of GDB up to the next prompt and build the completion list.
! (defun gud-gdb-fetch-lines-filter (string filter yes)
    "Filter used to read the list of lines output by a command.
  STRING is the output to filter.
  It is passed through FILTER before we look at it."
***************
*** 663,668 ****
--- 665,675 ----
    (while (string-match "\n" string)
      (push (substring string gud-gdb-fetch-lines-break (match-beginning 0))
          gud-gdb-fetched-lines)
+     (setq gud-gdb-items (+ 1 gud-gdb-items))
+     (unless (or yes (< gud-gdb-items 100))
+       (setq yes (y-or-n-p "Display all (over 100) possibilities? "))
+       
+       (unless yes (throw 'gdb-no-display nil)))
      (setq string (substring string (match-end 0))))
    (if (string-match comint-prompt-regexp string)
        (progn
***************
*** 744,761 ****
        nil
        ;; Much of this copied from GDB complete, but I'm grabbing the stack
        ;; frame instead.
!       (let ((gud-gdb-fetch-lines-in-progress t)
!           (gud-gdb-fetched-lines nil)
!           (gud-gdb-fetch-lines-string nil)
!           (gud-gdb-fetch-lines-break (or skip 0))
!           (gud-marker-filter
!            `(lambda (string) (gud-gdb-fetch-lines-filter string 
',gud-marker-filter))))
!       ;; Issue the command to GDB.
!       (gud-basic-call command)
!       ;; Slurp the output.
!       (while gud-gdb-fetch-lines-in-progress
!         (accept-process-output (get-buffer-process buffer)))
!       (nreverse gud-gdb-fetched-lines)))))
  
  
  ;; ======================================================================
--- 751,772 ----
        nil
        ;; Much of this copied from GDB complete, but I'm grabbing the stack
        ;; frame instead.
!       (catch 'gdb-no-display
!       (let ((gud-gdb-fetch-lines-in-progress t)
!             (gud-gdb-fetched-lines nil)
!             (gud-gdb-fetch-lines-string nil)
!             (gud-gdb-fetch-lines-break (or skip 0))
!             (gud-gdb-items 0)
!             (yes nil)
!             (gud-marker-filter
!              `(lambda (string)
!                 (gud-gdb-fetch-lines-filter string ',gud-marker-filter yes))))
!         ;; Issue the command to GDB.
!         (gud-basic-call command)
!         ;; Slurp the output.
!         (while gud-gdb-fetch-lines-in-progress
!           (accept-process-output (get-buffer-process buffer)))
!         (nreverse gud-gdb-fetched-lines))))))
  
  
  ;; ======================================================================