-;; Why is it needed? Well, if the selected window is in follow mode,
-;; all its followers stick to it blindly. If one of them is scrolled,
-;; it immediately returns to the original position when the mouse is
-;; released. If the selected window is not a follower of the dragged
-;; window the windows will be unaligned.
-
-;; The advices don't get compiled. Aesthetically, this might be a
-;; problem but in practical life it isn't.
-
-;; Discussion: Now when the other windows in the chain follow the
-;; dragged, should we really select it?
-
-(cond ((fboundp 'scroll-bar-drag)
- ;;;
- ;;; Emacs style scrollbars.
- ;;;
-
- ;; Select the dragged window if it is a follower of the
- ;; selected window.
- ;;
- ;; Generate advices of the form:
- ;; (defadvice scroll-bar-drag (after follow-scroll-bar-drag activate)
- ;; "Adviced by `follow-mode'."
- ;; (follow-redraw-after-event (ad-get-arg 0)))
- (let ((cmds '(scroll-bar-drag
- scroll-bar-drag-1 ; Executed at every move.
- scroll-bar-scroll-down
- scroll-bar-scroll-up
- scroll-bar-set-window-start)))
- (while cmds
- (eval
- `(defadvice ,(intern (symbol-name (car cmds)))
- (after
- ,(intern (concat "follow-" (symbol-name (car cmds))))
- activate)
- "Adviced by Follow mode."
- (follow-redraw-after-event (ad-get-arg 0))))
- (setq cmds (cdr cmds))))
-
-
- (defun follow-redraw-after-event (event)
- "Adviced by Follow mode."
- (condition-case nil
- (let* ((orig-win (selected-window))
- (win (nth 0 (funcall
- (symbol-function 'event-start) event)))
- (fmode (assq 'follow-mode
- (buffer-local-variables
- (window-buffer win)))))
- (if (and fmode (cdr fmode))
- ;; The selected window is in follow-mode
- (progn
- ;; Recenter around the dragged window.
- (select-window win)
- (follow-redisplay)
- (select-window orig-win))))
- (error nil))))
-
-
- ((fboundp 'scrollbar-vertical-drag)
- ;;;
- ;;; XEmacs style scrollbars.
- ;;;
-
- ;; Advice all scrollbar functions on the form:
- ;;
- ;; (defadvice scrollbar-line-down
- ;; (after follow-scrollbar-line-down activate)
- ;; (follow-xemacs-scrollbar-support (ad-get-arg 0)))
-
- (let ((cmds '(scrollbar-line-down ; Window
- scrollbar-line-up
- scrollbar-page-down ; Object
- scrollbar-page-up
- scrollbar-to-bottom ; Window
- scrollbar-to-top
- scrollbar-vertical-drag ; Object
- )))
-
- (while cmds
- (eval
- `(defadvice ,(intern (symbol-name (car cmds)))
- (after
- ,(intern (concat "follow-" (symbol-name (car cmds))))
- activate)
- "Adviced by `follow-mode'."
- (follow-xemacs-scrollbar-support (ad-get-arg 0))))
- (setq cmds (cdr cmds))))
-
-
- (defun follow-xemacs-scrollbar-support (window)
- "Redraw windows showing the same buffer as shown in WINDOW.
-WINDOW is either the dragged window, or a cons containing the
-window as its first element. This is called while the user drags
-the scrollbar.
-
-WINDOW can be an object or a window."
- (condition-case nil
- (progn
- (if (consp window)
- (setq window (car window)))
- (let ((fmode (assq 'follow-mode
- (buffer-local-variables
- (window-buffer window))))
- (orig-win (selected-window)))
- (if (and fmode (cdr fmode))
- (progn
- ;; Recenter around the dragged window.
- (select-window window)
- (follow-redisplay)
- (select-window orig-win)))))
- (error nil)))))
-
-;;}}}
-;;{{{ Process output
-
-;; The following sections installs a spy that listens to process
-;; output and tries to reposition the windows whose buffers are in
-;; Follow mode. We play safe as much as possible...
-;;
-;; When follow-mode is activated all active processes are
-;; intercepted. All new processes that change their filter function
-;; using `set-process-filter' are also intercepted. The reason is
-;; that a process can cause a redisplay recentering "tail" windows.
-;; Note that it doesn't hurt to spy on more processes than needed.
-;;
-;; Technically, we set the process filter to `follow-generic-filter'.
-;; The original filter is stored in `follow-process-filter-alist'.
-;; Our generic filter calls the original filter, or inserts the
-;; output into the buffer, if the buffer originally didn't have an
-;; output filter. It also makes sure that the windows connected to
-;; the buffer are aligned.
-;;
-;; Discussion: How do we find processes that don't call
-;; `set-process-filter'? (How often are processes created in a
-;; buffer after Follow mode are activated?)
-;;
-;; Discussion: Should we also advice `process-filter' to make our
-;; filter invisible to others?
-
-;;{{{ Advice for `set-process-filter'
-
-;; Do not call this with 'follow-generic-filter as the name of the
-;; filter...
-
-(defadvice set-process-filter (before follow-set-process-filter activate)
- "Ensure process output will be displayed correctly in Follow mode buffers.
-
-Follow mode inserts its own process filter to do its
-magic stuff before the real process filter is called."
- (if follow-intercept-processes
- (progn
- (setq follow-process-filter-alist
- (delq (assq (ad-get-arg 0) follow-process-filter-alist)
- follow-process-filter-alist))
- (follow-tidy-process-filter-alist)
- (cond ((eq (ad-get-arg 1) t))
- ((eq (ad-get-arg 1) nil)
- (ad-set-arg 1 'follow-generic-filter))
- (t
- (setq follow-process-filter-alist
- (cons (cons (ad-get-arg 0) (ad-get-arg 1))
- follow-process-filter-alist))
- (ad-set-arg 1 'follow-generic-filter))))))
-
-
-(defun follow-call-set-process-filter (proc filter)
- "Call original `set-process-filter' without the Follow mode advice."
- (ad-disable-advice 'set-process-filter 'before
- 'follow-set-process-filter)
- (ad-activate 'set-process-filter)
- (prog1
- (set-process-filter proc filter)
- (ad-enable-advice 'set-process-filter 'before
- 'follow-set-process-filter)
- (ad-activate 'set-process-filter)))
-
-
-(defadvice process-filter (after follow-process-filter activate)
- "Return the original process filter, not `follow-generic-filter'."
- (cond ((eq ad-return-value 'follow-generic-filter)
- (setq ad-return-value
- (cdr-safe (assq (ad-get-arg 0)
- follow-process-filter-alist))))))
-
-
-(defun follow-call-process-filter (proc)
- "Call original `process-filter' without the Follow mode advice."
- (ad-disable-advice 'process-filter 'after
- 'follow-process-filter)
- (ad-activate 'process-filter)
- (prog1
- (process-filter proc)
- (ad-enable-advice 'process-filter 'after
- 'follow-process-filter)
- (ad-activate 'process-filter)))
-
-
-(defun follow-tidy-process-filter-alist ()
- "Remove old processes from `follow-process-filter-alist'."
- (let ((alist follow-process-filter-alist)
- (ps (process-list))
- (new ()))
- (while alist
- (if (and (not (memq (process-status (car (car alist)))
- '(exit signal closed nil)))
- (memq (car (car alist)) ps))
- (setq new (cons (car alist) new)))
- (setq alist (cdr alist)))
- (setq follow-process-filter-alist new)))
-
-;;}}}
-;;{{{ Start/stop interception of processes.
-
-;; Normally, all new processes are intercepted by our `set-process-filter'.
-;; This is needed to intercept old processes that were started before we were
-;; loaded, and processes we have forgotten by calling
-;; `follow-stop-intercept-process-output'.
-
-(defun follow-intercept-process-output ()
- "Intercept all active processes.
-
-This is needed so that Follow mode can track all display events in the
-system. (See `follow-mode'.)"
- (interactive)
- (let ((list (process-list)))
- (while list
- (if (eq (process-filter (car list)) 'follow-generic-filter)
- nil
- ;; The custom `set-process-filter' defined above.
- (set-process-filter (car list) (process-filter (car list))))
- (setq list (cdr list))))
- (setq follow-intercept-processes t))
-
-
-(defun follow-stop-intercept-process-output ()
- "Stop Follow mode from spying on processes.
-
-All current spypoints are removed and no new will be added.
-
-The effect is that Follow mode won't be able to handle buffers
-connected to processes.
-
-The only reason to call this function is if the Follow mode spy filter
-would interfere with some other package. If this happens, please
-report this using the `report-emacs-bug' function."
- (interactive)
- (follow-tidy-process-filter-alist)
- (dolist (process (process-list))
- (when (eq (follow-call-process-filter process) 'follow-generic-filter)
- (follow-call-set-process-filter
- process
- (cdr-safe (assq process follow-process-filter-alist)))
- (setq follow-process-filter-alist
- (delq (assq process follow-process-filter-alist)
- follow-process-filter-alist))))
- (setq follow-intercept-processes nil))
-
-;;}}}
-;;{{{ The filter
-
-;; The following section is a naive method to make buffers with
-;; process output to work with Follow mode. Whenever the start of the
-;; window displaying the buffer is moved, we move it back to its
-;; original position and try to select a new window. (If we fail,
-;; the normal redisplay functions of Emacs will scroll it right
-;; back!)
-
-(defun follow-generic-filter (proc output)
- "Process output filter for process connected to buffers in Follow mode."
- (let* ((old-buffer (current-buffer))
- (orig-win (selected-window))
- (buf (process-buffer proc))
- (win (and buf (if (eq buf (window-buffer orig-win))
- orig-win
- (get-buffer-window buf t))))
- (return-to-orig-win (and win (not (eq win orig-win))))
- (orig-window-start (and win (window-start win))))
-
- ;; If input is pending, the `sit-for' below won't redraw the
- ;; display. In that case, calling `follow-avoid-tail-recenter' may
- ;; provoke the process handling code to schedule a redisplay.
- ;(or (input-pending-p)
- ; (follow-avoid-tail-recenter))
-
- ;; Output the `output'.
- (let ((filter (cdr-safe (assq proc follow-process-filter-alist))))
- (cond
- ;; Call the original filter function
- (filter
- (funcall filter proc output))
-
- ;; No filter, but we've got a buffer. Just output into it.
- (buf
- (set-buffer buf)
- (if (not (marker-buffer (process-mark proc)))
- (set-marker (process-mark proc) (point-max)))
- (let ((moving (= (point) (process-mark proc)))
- deactivate-mark
- (inhibit-read-only t))
- (save-excursion
- (goto-char (process-mark proc))
- ;; `insert-before-markers' just in case the user's next
- ;; command is M-y.
- (insert-before-markers output)
- (set-marker (process-mark proc) (point)))
- (if moving (goto-char (process-mark proc)))))))
-
- ;; If we're in follow mode, do our stuff. Select a new window and
- ;; redisplay. (Actually, it is redundant to check `buf', but I
- ;; feel it's more correct.)
- (if (and buf (window-live-p win))
- (progn
- (set-buffer buf)
- (if (and (boundp 'follow-mode) follow-mode)
- (progn
- (select-window win)
- (let* ((windows (follow-all-followers win))
- (win-start-end (follow-windows-start-end windows))
- (new-window-start (window-start win))
- (new-window-point (window-point win)))
- (cond
- ;; The start of the selected window was repositioned.
- ;; Try to use the original start position and continue
- ;; working with a window to the "right" in the window
- ;; chain. This will create the effect that the output
- ;; starts in one window and continues into the next.
-
- ;; If the display has changed so much that it is not
- ;; possible to keep the original window fixed and still
- ;; display the point then we give up and use the new
- ;; window start.
-
- ;; This case is typically used when the process filter
- ;; tries to reposition the start of the window in order
- ;; to view the tail of the output.
- ((not (eq orig-window-start new-window-start))
- (follow-debug-message "filter: Moved")
- (set-window-start win orig-window-start)
- (follow-redisplay windows win)
- (setq win-start-end (follow-windows-start-end windows))
- (follow-select-if-visible new-window-point
- win-start-end)
- (goto-char new-window-point)
- (if (eq win (selected-window))
- (set-window-start win new-window-start))
- (setq win-start-end (follow-windows-start-end windows)))
- ;; Stick to this window, if point is visible in it.
- ((pos-visible-in-window-p new-window-point)
- (follow-debug-message "filter: Visible in window"))
- ;; Avoid redisplaying the first window. If the
- ;; point is visible at a window below,
- ;; redisplay and select it.
- ((follow-select-if-visible-from-first
- new-window-point windows)
- (follow-debug-message "filter: Seen from first")
- (setq win-start-end
- (follow-windows-start-end windows)))
- ;; None of the above. We stick to the current window.
- (t
- (follow-debug-message "filter: nothing")))
-
- ;; Here we have selected a window. Make sure the
- ;; windows are aligned and the point is visible
- ;; in the selected window.
- (if (and (not (follow-pos-visible
- (point) (selected-window) win-start-end))
- (not return-to-orig-win))
- (progn
- (sit-for 0)
- (setq win-start-end
- (follow-windows-start-end windows))))
-
- (if (or follow-internal-force-redisplay
- (not (follow-windows-aligned-p win-start-end)))
- (follow-redisplay windows)))))))
-
- ;; return to the original window.
- (if return-to-orig-win
- (select-window orig-win))
- ;; Restore the original buffer, unless the filter explicitly
- ;; changed buffer or killed the old buffer.
- (if (and (eq buf (current-buffer))
- (buffer-name old-buffer))
- (set-buffer old-buffer)))
-
- (follow-invalidate-cache)
-
- ;; Normally, if the display has been changed, it is redrawn. All
- ;; windows showing only the end of a buffer are unconditionally
- ;; recentered; we can't prevent that by calling
- ;; `follow-avoid-tail-recenter'.
- ;;
- ;; We force a redisplay here on our own, so Emacs does need to.
- ;; (However, redisplaying when there's input available just seems
- ;; to make things worse, so we exclude that case.)
- (if (and follow-avoid-tail-recenter-p
- (not (input-pending-p)))
- (sit-for 0)))
-
-;;}}}
-
-;;}}}
-;;{{{ Window size change
-
-;; In Emacs 19.29, the functions in `window-size-change-functions' are
-;; called every time a window in a frame changes size. Most notably, it
-;; is called after the frame has been resized.
-;;
-;; We basically call our post-command-hook for every buffer that is
-;; visible in any window in the resized frame, which is in follow-mode.
-;;
-;; Since this function can be called indirectly from
-;; `follow-post-command-hook' we have a potential infinite loop. We
-;; handle this problem by simply not doing anything at all in this
-;; situation. The variable `follow-inside-post-command-hook' contains
-;; information about whether the execution actually is inside the