Various optimizations. The main one is to optimize for

simple output at the end of the buffer, with no paging, and in that
case to defer scrolling while we can.
(term-emulate-terminal):  Don't call term-handle-scroll in
simple cases unless we are either paging or term-scroll-with-delete.
(term-down):  Likewise.
(term-handle-scroll):  Modify accordingly.
(term-emulate-terminal):  Avoid deleting old text in common case.
Optimize the simple case of CRLF when we're at buffer end.
Handle deferred scroll when done processing output.
(term-handle-deferred-scroll):  New function.
(term-down):  Simplify - no longer take RIGHT argument.  Tune.
(term-goto):  Use term-move-columns to compensate for the above.

(term-escape-char, term-set-escape-char):  Add doc-string.
(term-mouse-paste):  Add xemacs support.

Various speed enhencements:
(term-handle-scroll):  Don't clear term-current-row; maybe adjust it.
(term-down):  Don't call term-adjust-current-row-cache if we've
done term-handle-scroll.
(term-emulate-terminal):  Don't call term-adjust-current-row-cache.
(term-emulate-terminal):  For TAB, don't nil term-start-line-column.
(term-goto):  Possible optimization.

1 files changed, 99 insertions, 40 deletions

diff --git a/lisp/term.el b/lisp/term.el
index 3ab6c0711e2..1d340883841 100644
--- a/lisp/term.el
+++ b/lisp/term.el
@@ -283,7 +283,9 @@ executed once when the buffer is created.")
 (defvar term-mode-map nil)
 (defvar term-raw-map nil
   "Keyboard map for sending characters directly to the inferior process.")
-(defvar term-escape-char nil)
+(defvar term-escape-char nil
+  "Escape character for char-sub-mode of term mode.
+Do not change it directly;  use term-set-escape-char instead.")
 (defvar term-raw-escape-map nil)
 
 (defvar term-pager-break-map nil)
@@ -690,6 +692,7 @@ without any interpretation."
 (defun term-send-left  () (interactive) (term-send-raw-string "\e[D"))
 
 (defun term-set-escape-char (c)
+  "Change term-escape-char and keymaps that depend on it."
   (if term-escape-char
       (define-key term-raw-map term-escape-char 'term-send-raw))
   (setq c (make-string 1 c))
@@ -2126,24 +2129,31 @@ See `term-prompt-regexp'."
                                    ;; This iteration, handle only what fits.
                                    (setq count (- count temp))
                                    (setq funny (+ count i)))
-                                  ((>  (term-handle-scroll 1) 0)
+                                  ((or (not (or term-pager-count
+                                                term-scroll-with-delete))
+                                       (>  (term-handle-scroll 1) 0))
+                                   (term-adjust-current-row-cache 1)
                                    (setq count (min count term-width))
                                    (setq funny (+ count i))
-                                   (term-adjust-current-row-cache 1)
                                    (setq term-start-line-column
                                          term-current-column))
                                   (t ;; Doing PAGER processing.
                                    (setq count 0 funny i)
                                    (setq term-current-column nil)
                                    (setq term-start-line-column nil)))
-                            (if term-insert-mode
-                                ;; Inserting spaces, then deleting them, then
-                                ;; inserting the actual text seems clumsy, but
-                                ;; it is simple, and the overhead is miniscule.
-                                (term-insert-spaces count))
                             (setq old-point (point))
-                            (term-move-columns count)
-                            (delete-region old-point (point))
+                            ;; In the common case that we're at the end of
+                            ;; the buffer, we can save a little work.
+                            (cond ((/= (point) (point-max))
+                                   (if term-insert-mode
+                                       ;; Inserting spaces, then deleting them,
+                                       ;; then inserting the actual text is
+                                       ;; inefficient, but it is simple, and
+                                       ;; the actual overhead is miniscule.
+                                       (term-insert-spaces count))
+                                   (term-move-columns count)
+                                   (delete-region old-point (point)))
+        (t (setq term-current-column (+ (term-current-column) count))))
                             (insert (substring str i funny))
                             (put-text-property old-point (point)
                                                'face term-current-face)
@@ -2161,17 +2171,29 @@ See `term-prompt-regexp'."
                             (setq count (+ count 8 (- (mod count 8))))
                             (if (< (move-to-column count nil) count)
                                 (term-insert-char char 1))
-                            (setq term-current-column count)
-                            (setq term-start-line-column nil))
-                           ((eq char ?\b)
-                            (term-move-columns -1))
+                            (setq term-current-column count))
                            ((eq char ?\r)
-                            (term-vertical-motion 0)
-                            (setq term-current-column nil))
+                            ;; Optimize CRLF at end of buffer:
+                            (cond ((and (< (setq temp (1+ i)) str-length)
+                                        (eq (aref str temp) ?\n)
+                                        (= (point) (point-max))
+                                        (not (or term-pager-count
+                                                 term-kill-echo-list
+                                                 term-scroll-with-delete)))
+                                   (insert ?\n)
+                                   (term-adjust-current-row-cache 1)
+                                   (setq term-start-line-column 0)
+                                   (setq term-current-column 0)
+                                   (setq i temp))
+                                  (t ;; Not followed by LF or can't optimize:
+                                   (term-vertical-motion 0)
+                                   (setq term-current-column 0))))
                            ((eq char ?\n)
                             (if (not (and term-kill-echo-list
                                           (term-check-kill-echo-list)))
-                                (term-down 1 0 t)))
+                                (term-down 1 t)))
+                           ((eq char ?\b)
+                            (term-move-columns -1))
                            ((eq char ?\033) ; Escape
                             (setq term-terminal-state 2))
                            ((eq char 0)) ; NUL: Do nothing
@@ -2201,12 +2223,14 @@ See `term-prompt-regexp'."
                             (setq term-terminal-previous-parameter 0)
                             (setq term-terminal-state 3))
                            ((eq char ?D) ;; scroll forward
-                            (term-down 1 0 t)
+                            (term-handle-deferred-scroll)
+                            (term-down 1 t)
                             (setq term-terminal-state 0))
                            ((eq char ?M) ;; scroll reversed
                             (term-insert-lines 1)
                             (setq term-terminal-state 0))
                            ((eq char ?7) ;; Save cursor
+                            (term-handle-deferred-scroll)
                             (setq term-saved-cursor
                                   (cons (term-current-row)
                                         (term-horizontal-column)))
@@ -2250,6 +2274,9 @@ See `term-prompt-regexp'."
                     (setq i str-length)))
               (setq i (1+ i))))
 
+          (if (>= (term-current-row) term-height)
+              (term-handle-deferred-scroll))
+
           (set-marker (process-mark proc) (point))
           (if save-point
               (progn (goto-char save-point)
@@ -2300,6 +2327,15 @@ See `term-prompt-regexp'."
       (set-buffer previous-buffer)
       (select-window selected))))
 
+(defun term-handle-deferred-scroll ()
+  (let ((count (- (term-current-row) term-height)))
+    (if (> count 0)
+        (save-excursion
+          (goto-char term-home-marker)
+          (term-vertical-motion count)
+          (set-marker term-home-marker (point))
+          (setq term-current-row (1- term-height))))))
+
 ;;; Handle a character assuming (eq terminal-state 2) -
 ;;; i.e. we have previousely seen Escape followed by ?[.
 
@@ -2319,10 +2355,11 @@ See `term-prompt-regexp'."
      (1- term-terminal-parameter)))
    ;; \E[A - cursor up
    ((eq char ?A)
-    (term-down (- (max 1 term-terminal-parameter)) 0 t))
+    (term-handle-deferred-scroll)
+    (term-down (- (max 1 term-terminal-parameter)) t))
    ;; \E[B - cursor down
    ((eq char ?B)
-    (term-down (max 1 term-terminal-parameter) 0 t))
+    (term-down (max 1 term-terminal-parameter) t))
    ;; \E[C - cursor right
    ((eq char ?C)
     (term-move-columns (max 1 term-terminal-parameter)))
@@ -2370,6 +2407,7 @@ See `term-prompt-regexp'."
           (t (setq term-current-face 'default))))
    ;; \E[6n - Report cursor position
    ((eq char ?n)
+    (term-handle-deferred-scroll)
     (process-send-string proc
                          (format "\e[%s;%sR"
                                  (1+ (term-current-row))
@@ -2403,6 +2441,7 @@ The top-most line is line 0."
   ;; If asked to switch to (from) the alternate sub-buffer, and already (not)
   ;; using it, do nothing.  This test is needed for some programs (including
   ;; emacs) that emit the ti termcap string twice, for unknown reason.
+  (term-handle-deferred-scroll)
   (if (eq set (not (term-using-alternate-sub-buffer)))
       (let ((row (term-current-row))
             (col (term-horizontal-column)))
@@ -2477,22 +2516,30 @@ The top-most line is line 0."
 ;;; "down" as needed so that is no more that a window-full above (point-max).
 
 (defun term-goto-home ()
+  (term-handle-deferred-scroll)
   (goto-char term-home-marker)
   (setq term-current-row 0)
   (setq term-current-column (current-column))
   (setq term-start-line-column term-current-column))
 
-;;; FIXME:  This can be optimized some.
 (defun term-goto (row col)
-  (term-goto-home)
-  (term-down row col))
+  (term-handle-deferred-scroll)
+  (cond ((and term-current-row (>= row term-current-row))
+         ;; I assume this is a worthwhile optimization.
+         (term-vertical-motion 0)
+         (setq term-current-column term-start-line-column)
+         (setq row (- row term-current-row)))
+        (t
+         (term-goto-home)))
+  (term-down row)
+  (term-move-columns col))
 
 ; The page is full, so enter "pager" mode, and wait for input.
 
 (defun term-process-pager ()
   (if (not term-pager-break-map)
       (let* ((map (make-keymap))
-            (i 0) tmp)
+             (i 0) tmp)
 ;       (while (< i 128)
 ;         (define-key map (make-string 1 i) 'term-send-raw)
 ;         (setq i (1+ i)))
@@ -2681,6 +2728,8 @@ all pending output has been dealt with."))
                  (delete-region save-top (point))
                  (goto-char save-point)
                  (term-vertical-motion down)
+                 (term-adjust-current-row-cache (- scroll-needed))
+                 (setq term-current-column nil)
                  (term-insert-char ?\n scroll-needed))
                 ((and (numberp term-pager-count)
                       (< (setq term-pager-count (- term-pager-count down))
@@ -2688,26 +2737,31 @@ all pending output has been dealt with."))
                  (setq down 0)
                  (term-process-pager))
                 (t
+                 (term-adjust-current-row-cache (- scroll-needed))
                  (term-vertical-motion scroll-needed)
                  (set-marker term-home-marker (point))))
           (goto-char save-point)
-          (set-marker save-point nil)
-          (setq term-current-column nil)
-          (setq term-current-row nil))))
+          (set-marker save-point nil))))
   down)
 
-(defun term-down (down right &optional check-for-scroll)
-  "Move down DOWN screen lines vertically, and RIGHT columns horizontally."
+(defun term-down (down &optional check-for-scroll)
+  "Move down DOWN screen lines vertically."
   (let ((start-column (term-horizontal-column)))
-    (if check-for-scroll
+    (if (and check-for-scroll (or term-scroll-with-delete term-pager-count))
         (setq down (term-handle-scroll down)))
     (term-adjust-current-row-cache down)
-    (setq down (- down (term-vertical-motion down)))
-    ; Extend buffer with extra blank lines if needed.
-    (if (> down 0) (term-insert-char ?\n down))
-    (setq term-current-column nil)
-    (setq term-start-line-column (current-column))
-    (move-to-column (+ term-start-line-column start-column right) t)))
+    (if (/= (point) (point-max))
+        (setq down (- down (term-vertical-motion down))))
+    ;; Extend buffer with extra blank lines if needed.
+    (cond ((> down 0)
+           (term-insert-char ?\n down)
+           (setq term-current-column 0)
+           (setq term-start-line-column 0))
+          (t
+           (setq term-current-column nil)
+           (setq term-start-line-column (current-column))))
+    (if start-column
+        (term-move-columns start-column))))
 
 ;; Assuming point is at the beginning of a screen line,
 ;; if the line above point wraps around, add a ?\n to undo the wrapping.
@@ -2747,6 +2801,7 @@ all pending output has been dealt with."))
 If KIND is 0, erase from (point) to (point-max);
 if KIND is 1, erase from home to point; else erase from home to point-max.
 Should only be called when point is at the start of a screen line."
+  (term-handle-deferred-scroll)
   (cond ((eq term-terminal-parameter 0)
          (delete-region (point) (point-max))
          (term-unwrap-line))
@@ -2770,6 +2825,10 @@ Should only be called when point is at the start of a screen line."
     (move-to-column (+ (term-current-column) count) t)
     (delete-region save-point (point))))
 
+;;; Insert COUNT spaces after point, but do not change any of
+;;; following screen lines.  Hence we may have to delete characters
+;;; at teh end of this screen line to make room.
+
 (defun term-insert-spaces (count)
   (let ((save-point (point)) (save-eol))
     (term-vertical-motion 1)
@@ -2788,9 +2847,9 @@ Should only be called when point is at the start of a screen line."
         (save-current-column term-current-column)
         (save-start-line-column term-start-line-column)
         (save-current-row (term-current-row)))
-    (term-down lines 0)
+    (term-down lines)
     (delete-region start (point))
-    (term-down (- term-scroll-end save-current-row lines) 0)
+    (term-down (- term-scroll-end save-current-row lines))
     (term-insert-char ?\n lines)
     (setq term-current-column save-current-column)
     (setq term-start-line-column save-start-line-column)
@@ -2803,9 +2862,9 @@ Should only be called when point is at the start of a screen line."
         (save-current-column term-current-column)
         (save-start-line-column term-start-line-column)
         (save-current-row (term-current-row)))
-    (term-down (- term-scroll-end save-current-row lines) 0)
+    (term-down (- term-scroll-end save-current-row lines))
     (setq start-deleted (point))
-    (term-down lines 0)
+    (term-down lines)
     (delete-region start-deleted (point))
     (goto-char start)
     (setq term-current-column save-current-column)