;; Boston, MA 02111-1307, USA.
;;; Commentary:
-;; This package provides basic chunk operations for VLF
+;; This package provides basic chunk operations for VLF,
+;; most notable being the `vlf-move-to-chunk' function.
;;; Code:
-(defconst vlf-min-chunk-size 16
+(defgroup vlf nil
+ "View Large Files in Emacs."
+ :prefix "vlf-"
+ :group 'files)
+
+(defcustom vlf-batch-size 1024
+ "Defines how large each batch of file data is (in bytes)."
+ :group 'vlf
+ :type 'integer)
+(put 'vlf-batch-size 'permanent-local t)
+
+;;; Keep track of file position.
+(defvar vlf-start-pos 0
+ "Absolute position of the visible chunk start.")
+(make-variable-buffer-local 'vlf-start-pos)
+(put 'vlf-start-pos 'permanent-local t)
+
+(defvar vlf-end-pos 0 "Absolute position of the visible chunk end.")
+(make-variable-buffer-local 'vlf-end-pos)
+(put 'vlf-end-pos 'permanent-local t)
+
+(defvar vlf-file-size 0 "Total size of presented file.")
+(make-variable-buffer-local 'vlf-file-size)
+(put 'vlf-file-size 'permanent-local t)
+
+(defconst vlf-sample-size 24
"Minimal number of bytes that can be properly decoded.")
-(defconst vlf-partial-decode-shown
- (cond ((< emacs-major-version 24) t)
- ((< 24 emacs-major-version) nil)
- (t ;; TODO: use (< emacs-minor-version 4) after 24.4 release
- (string-lessp emacs-version "24.3.5")))
- "Indicates whether partial decode codes are displayed.")
+(defun vlf-get-file-size (file)
+ "Get size in bytes of FILE."
+ (or (nth 7 (file-attributes file)) 0))
+
+(defun vlf-verify-size (&optional update-visited-time)
+ "Update file size information if necessary and visited file time.
+If non-nil, UPDATE-VISITED-TIME."
+ (unless (verify-visited-file-modtime (current-buffer))
+ (setq vlf-file-size (vlf-get-file-size buffer-file-truename))
+ (if update-visited-time
+ (set-visited-file-modtime))))
+
+(unless (fboundp 'file-size-human-readable)
+ (defun file-size-human-readable (file-size)
+ "Print FILE-SIZE in MB."
+ (format "%.3fMB" (/ file-size 1048576.0))))
+
+(defun vlf-update-buffer-name ()
+ "Update the current buffer name."
+ (rename-buffer (format "%s(%d/%d)[%s]"
+ (file-name-nondirectory buffer-file-name)
+ (/ vlf-end-pos vlf-batch-size)
+ (/ vlf-file-size vlf-batch-size)
+ (file-size-human-readable vlf-batch-size))
+ t))
+
+(defmacro vlf-with-undo-disabled (&rest body)
+ "Execute BODY with temporarily disabled undo."
+ `(let ((undo-list buffer-undo-list))
+ (setq buffer-undo-list t)
+ (unwind-protect (progn ,@body)
+ (setq buffer-undo-list undo-list))))
(defun vlf-move-to-chunk (start end &optional minimal)
- "Move to chunk determined by START END.
+ "Move to chunk enclosed by START END bytes.
When given MINIMAL flag, skip non important operations.
If same as current chunk is requested, do nothing.
Return number of bytes moved back for proper decoding and number of
shifts)))
(defun vlf-move-to-chunk-1 (start end)
- "Move to chunk determined by START END keeping as much edits if any.
+ "Move to chunk enclosed by START END keeping as much edits if any.
Return number of bytes moved back for proper decoding and number of
bytes added to the end."
+ (widen)
(let* ((modified (buffer-modified-p))
(start (max 0 start))
(end (min end vlf-file-size))
buffer-file-coding-system t)))
vlf-end-pos)))
(cond
- ((and (= start vlf-start-pos) (= end edit-end))
- (or modified (vlf-move-to-chunk-2 start end)))
- ((or (<= edit-end start) (<= end vlf-start-pos))
+ ((or (< edit-end start) (< end vlf-start-pos)
+ (not (verify-visited-file-modtime (current-buffer))))
(when (or (not modified)
(y-or-n-p "Chunk modified, are you sure? ")) ;full chunk renewal
(set-buffer-modified-p nil)
(vlf-move-to-chunk-2 start end)))
+ ((and (= start vlf-start-pos) (= end edit-end))
+ (or modified (vlf-move-to-chunk-2 start end)))
((or (and (<= start vlf-start-pos) (<= edit-end end))
(not modified)
(y-or-n-p "Chunk modified, are you sure? "))
(let ((pos (+ (position-bytes (point)) vlf-start-pos))
(inhibit-read-only t))
(cond ((< end edit-end)
- (let* ((del-pos (1+ (byte-to-position
- (- end vlf-start-pos))))
+ (let* ((del-pos (1+ (or (byte-to-position
+ (- end vlf-start-pos))
+ 0)))
(del-len (length (encode-coding-region
del-pos (point-max)
buffer-file-coding-system
(vlf-with-undo-disabled
(delete-region del-pos (point-max)))))
((< edit-end end)
- (if (and (not vlf-partial-decode-shown)
- (< (- end vlf-end-pos) 4))
- (setq end vlf-end-pos)
- (vlf-with-undo-disabled
- (setq shift-end (cdr (vlf-insert-file-contents
- vlf-end-pos end nil t
- (point-max))))))))
+ (vlf-with-undo-disabled
+ (setq shift-end (cdr (vlf-insert-file-contents
+ vlf-end-pos end
+ (/= start vlf-end-pos) t
+ (point-max)))))))
(cond ((< vlf-start-pos start)
(let* ((del-pos (1+ (byte-to-position
(- start vlf-start-pos))))
(setq start (+ vlf-start-pos del-len))
(vlf-with-undo-disabled
(delete-region (point-min) del-pos))
- (vlf-shift-undo-list (- 1 del-pos))))
+ (vlf-shift-undo-list (- (point-min) del-pos))))
((< start vlf-start-pos)
- (if (and (not vlf-partial-decode-shown)
- (< (- vlf-start-pos start) 4))
- (setq start vlf-start-pos)
- (let ((edit-end-pos (point-max)))
- (vlf-with-undo-disabled
- (setq shift-start (car (vlf-insert-file-contents
- start vlf-start-pos
- t nil edit-end-pos)))
- (goto-char (point-min))
- (insert (delete-and-extract-region
- edit-end-pos (point-max))))
- (vlf-shift-undo-list (- (point-max) edit-end-pos))))))
+ (let ((edit-end-pos (point-max)))
+ (vlf-with-undo-disabled
+ (setq shift-start (car (vlf-insert-file-contents
+ start vlf-start-pos t
+ (/= end vlf-start-pos)
+ edit-end-pos)))
+ (goto-char (point-min))
+ (insert (delete-and-extract-region
+ edit-end-pos (point-max))))
+ (vlf-shift-undo-list (- (point-max) edit-end-pos)))))
(setq start (- start shift-start))
(goto-char (or (byte-to-position (- pos start))
(byte-to-position (- pos vlf-start-pos))
(setq vlf-start-pos start
vlf-end-pos (+ end shift-end)))
(set-buffer-modified-p modified)
+ (set-visited-file-modtime)
(cons shift-start shift-end))))))
(defun vlf-move-to-chunk-2 (start end)
- "Unconditionally move to chunk determined by START END.
+ "Unconditionally move to chunk enclosed by START END bytes.
Return number of bytes moved back for proper decoding and number of
bytes added to the end."
+ (vlf-verify-size t)
(setq vlf-start-pos (max 0 start)
vlf-end-pos (min end vlf-file-size))
(let (shifts)
(point-max)))))
(set-buffer-modified-p nil)
(setq buffer-undo-list nil)
- (set-visited-file-modtime)
shifts))
(defun vlf-insert-file-contents (start end adjust-start adjust-end
(setq adjust-start (and adjust-start (not (zerop start)))
adjust-end (and adjust-end (< end vlf-file-size))
position (or position (point-min)))
+ (goto-char position)
(let ((shift-start 0)
- (shift-end 0))
+ (shift-end 0)
+ (safe-end (if adjust-end
+ (min vlf-file-size (+ end 4))
+ end)))
(if adjust-start
- (setq shift-start (vlf-adjust-start start end position
+ (setq shift-start (vlf-adjust-start start safe-end position
adjust-end)
start (- start shift-start))
- (setq shift-end (vlf-insert-content-safe start end position)
- end (+ end shift-end)))
+ (vlf-insert-file-contents-safe start safe-end position))
(if adjust-end
- (setq shift-end (+ shift-end
- (vlf-adjust-end start end position))))
+ (setq shift-end (vlf-adjust-end start end position)))
(cons shift-start shift-end)))
(defun vlf-adjust-start (start end position adjust-end)
be properly decoded. Use buffer POSITION as start.
ADJUST-END is non-nil if end would be adjusted later.
Return number of bytes moved back for proper decoding."
- (let* ((min-end (min end (+ start vlf-min-chunk-size)))
- (chunk-size (- min-end start))
- (strict (and (not adjust-end) (= min-end end)))
- (shift (vlf-insert-content-safe start min-end position t)))
- (setq start (- start shift))
- (while (and (not (zerop start))
+ (let* ((safe-start (max 0 (- start 4)))
+ (sample-end (min end (+ safe-start vlf-sample-size)))
+ (chunk-size (- sample-end safe-start))
+ (strict (or (= sample-end vlf-file-size)
+ (and (not adjust-end) (= sample-end end))))
+ (shift 0))
+ (while (and (progn (vlf-insert-file-contents-safe
+ safe-start sample-end position)
+ (not (zerop safe-start)))
(< shift 3)
(let ((diff (- chunk-size
(length
(encode-coding-region
position (point-max)
buffer-file-coding-system t)))))
- (cond (strict (not (zerop diff)))
- (vlf-partial-decode-shown
- (or (< diff -3) (< 0 diff)))
- (t (or (< diff 0) (< 3 diff))))))
+ (if strict
+ (not (zerop diff))
+ (or (< diff -3) (< 0 diff)))))
(setq shift (1+ shift)
- start (1- start)
+ safe-start (1- safe-start)
chunk-size (1+ chunk-size))
- (delete-region position (point-max))
- (insert-file-contents buffer-file-name nil start min-end))
- (unless (= min-end end)
- (delete-region position (point-max))
- (insert-file-contents buffer-file-name nil start end))
- shift))
+ (delete-region position (point-max)))
+ (let ((cut-pos position)
+ (cut-len 0))
+ (while (< safe-start start)
+ (setq cut-len (length (encode-coding-region
+ cut-pos (1+ cut-pos)
+ buffer-file-coding-system t))
+ cut-pos (1+ cut-pos)
+ safe-start (+ safe-start cut-len)))
+ (if (< start safe-start)
+ (setq safe-start (- safe-start cut-len)
+ cut-pos (1- cut-pos)))
+ (if (= sample-end end)
+ (delete-region position cut-pos)
+ (delete-region position (point-max))
+ (vlf-insert-file-contents-safe safe-start end position)))
+ (- start safe-start)))
(defun vlf-adjust-end (start end position)
- "Adjust chunk end at absolute START to END till content can be\
-properly decoded starting at POSITION.
-Return number of bytes added for proper decoding."
- (let ((shift 0))
- (if vlf-partial-decode-shown
- (let ((new-pos (max position
- (- (point-max) vlf-min-chunk-size))))
- (if (< position new-pos)
- (setq start (+ start (length (encode-coding-region
- position new-pos
- buffer-file-coding-system
- t)))
- position new-pos))))
- (let ((chunk-size (- end start)))
- (goto-char (point-max))
- (while (and (< shift 3)
- (< end vlf-file-size)
- (or (eq (char-charset (preceding-char)) 'eight-bit)
- (/= chunk-size
- (length (encode-coding-region
- position (point-max)
- buffer-file-coding-system t)))))
- (setq shift (1+ shift)
- end (1+ end)
- chunk-size (1+ chunk-size))
- (delete-region position (point-max))
- (insert-file-contents buffer-file-name nil start end)
- (goto-char (point-max))))
- shift))
+ "Adjust chunk end at absolute START to END starting at POSITION.
+Remove characters from the end until length is closest to expected.
+Return number of bytes added over expected."
+ (let ((expected-size (- end start))
+ (current-size (length (encode-coding-region
+ position (point-max)
+ buffer-file-coding-system t)))
+ (cut-point (point-max))
+ (cut-len 0))
+ (while (< expected-size current-size)
+ (setq cut-len (length (encode-coding-region
+ (1- cut-point) cut-point
+ buffer-file-coding-system t))
+ cut-point (1- cut-point)
+ current-size (- current-size cut-len)))
+ (if (< current-size expected-size)
+ (setq cut-point (1+ cut-point)
+ current-size (+ current-size cut-len)))
+ (delete-region cut-point (point-max))
+ (- current-size expected-size)))
-(defun vlf-insert-content-safe (start end position &optional shift-start)
- "Insert file content from absolute START to END of file at\
-POSITION. Adjust start if SHIFT-START is non nil, end otherwise.
-Clean up if no characters are inserted."
- (goto-char position)
- (let ((shift 0))
- (while (and (< shift 3)
- (zerop (cadr (insert-file-contents buffer-file-name
- nil start end)))
- (if shift-start
- (not (zerop start))
- (< end vlf-file-size)))
- ;; TODO: this seems like regression after Emacs 24.3
- (message "Buffer content may be broken")
- (setq shift (1+ shift))
- (if shift-start
- (setq start (1- start))
- (setq end (1+ end)))
- (delete-region position (point-max)))
- shift))
+(defun vlf-insert-file-contents-safe (start end position)
+ "Extract decoded file bytes START to END at POSITION."
+ (let ((coding buffer-file-coding-system))
+ (insert-file-contents-literally buffer-file-name nil start end)
+ (let ((coding-system-for-read coding))
+ (decode-coding-inserted-region position (point-max)
+ buffer-file-name nil start end)))
+ (setq buffer-file-coding-system last-coding-system-used))
(defun vlf-shift-undo-list (n)
"Shift undo list element regions by N."