Function: erc-truncate-buffer-to-size

erc-truncate-buffer-to-size is an autoloaded and byte-compiled function defined in erc-truncate.el.gz.

Signature

(erc-truncate-buffer-to-size SIZE &optional BUFFER)

Documentation

Truncates the buffer to the size SIZE.

If BUFFER is not provided, the current buffer is assumed. The deleted region is logged if erc-logging-enabled returns non-nil.

Source Code

;; Defined in /usr/src/emacs/lisp/erc/erc-truncate.el.gz
;;;###autoload
(defun erc-truncate-buffer-to-size (size &optional buffer)
  "Truncates the buffer to the size SIZE.
If BUFFER is not provided, the current buffer is assumed.  The deleted
region is logged if `erc-logging-enabled' returns non-nil."
  ;; If buffer is non-nil, but get-buffer does not return anything,
  ;; then this is a bug.  If buffer is a buffer name, get the buffer
  ;; object.  If buffer is nil, use the current buffer.
  (if (not buffer)
      (setq buffer (current-buffer))
    (unless (get-buffer buffer)
      (error "erc-truncate-buffer-to-size: %S is not a buffer" buffer)))
  (when (> (buffer-size buffer) (+ size 512))
    (with-current-buffer buffer
      ;; Note that when erc-insert-post-hook runs, the buffer is
      ;; narrowed to the new message.  So do this delicate widening.
      ;; I am not sure, I think this was not recommended behavior in
      ;; Emacs 20.
      (save-restriction
	(widen)
	(let ((end (- erc-insert-marker size)))
	  ;; truncate at line boundaries
	  (goto-char end)
	  (beginning-of-line)
	  (setq end (point))
	  ;; try to save the current buffer using
	  ;; `erc-save-buffer-in-logs'.  We use this, in case the
	  ;; user has both `erc-save-buffer-in-logs' and
	  ;; `erc-truncate-buffer' in `erc-insert-post-hook'.  If
	  ;; this is the case, only the non-saved part of the current
	  ;; buffer should be saved.  Rather than appending the
	  ;; deleted part of the buffer to the log file.
	  ;;
	  ;; Alternatively this could be made conditional on:
	  ;; (not (memq 'erc-save-buffer-in-logs
	  ;;             erc-insert-post-hook))
	  ;; Comments?
	  (when (and (boundp 'erc-enable-logging)
		     erc-enable-logging
		     (erc-logging-enabled buffer))
	    (erc-save-buffer-in-logs))
	  ;; disable undoing for the truncating
	  (buffer-disable-undo)
	  (let ((inhibit-read-only t))
	    (delete-region (point-min) end)))
	(buffer-enable-undo)))))