-;;; vlf.el --- View Large Files
+;;; vlf.el --- View Large Files -*- lexical-binding: t -*-
-;; Copyright (C) 2006, 2012 Free Software Foundation, Inc.
+;; Copyright (C) 2006, 2012, 2013 Free Software Foundation, Inc.
-;; Version: 0.2
+;; Version: 1.1
;; Keywords: large files, utilities
+;; Maintainer: Andrey Kotlarski <m00naticus@gmail.com>
;; Authors: 2006 Mathias Dahl <mathias.dahl@gmail.com>
;; 2012 Sam Steingold <sds@gnu.org>
+;; 2013 Andrey Kotlarski <m00naticus@gmail.com>
+;; URL: https://github.com/m00natic/vlfi
;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;;; Commentary:
;; This package provides the M-x vlf command, which visits part of a
-;; large file in a read-only buffer without visiting the entire file.
-;; The buffer uses VLF mode, which defines the commands M-<next>
-;; (vlf-next-batch) and M-<prior> (vlf-prev-batch) to visit other
-;; parts of the file. The option `vlf-batch-size' specifies the size
-;; of each batch, in bytes.
+;; large file without loading the entire file.
+;; The buffer uses VLF mode, which defines several commands for
+;; moving around, searching and editing selected part of file.
;; This package was inspired by a snippet posted by Kevin Rodgers,
;; showing how to use `insert-file-contents' to extract part of a
"Defines how large each batch of file data is (in bytes)."
:type 'integer
:group 'vlf)
+(put 'vlf-batch-size 'permanent-local t)
-;; Keep track of file position.
-(defvar vlf-start-pos)
-(defvar vlf-end-pos)
-(defvar vlf-file-size)
+;;; Keep track of file position.
+(defvar vlf-start-pos 0
+ "Absolute position of the visible chunk start.")
+(put 'vlf-start-pos 'permanent-local t)
+
+(defvar vlf-end-pos 0 "Absolute position of the visible chunk end.")
+(put 'vlf-end-pos 'permanent-local t)
+
+(defvar vlf-file-size 0 "Total size of presented file.")
+(put 'vlf-file-size 'permanent-local t)
(defvar vlf-mode-map
- (let ((map (make-sparse-keymap)))
- (define-key map [M-next] 'vlf-next-batch)
- (define-key map [M-prior] 'vlf-prev-batch)
- (define-key map (kbd "C-+") 'vlf-change-batch-size)
- map)
+ (let ((map-prefix (make-sparse-keymap))
+ (map (make-sparse-keymap)))
+ (define-key map [next] 'vlf-next-batch)
+ (define-key map [prior] 'vlf-prev-batch)
+ (define-key map "n" 'vlf-next-batch-from-point)
+ (define-key map "+" 'vlf-change-batch-size)
+ (define-key map "-"
+ (lambda () "Decrease vlf batch size by factor of 2."
+ (interactive)
+ (vlf-change-batch-size t)))
+ (define-key map "s" 'vlf-re-search-forward)
+ (define-key map "r" 'vlf-re-search-backward)
+ (define-key map "o" 'vlf-occur)
+ (define-key map "[" 'vlf-beginning-of-file)
+ (define-key map "]" 'vlf-end-of-file)
+ (define-key map "j" 'vlf-jump-to-chunk)
+ (define-key map "l" 'vlf-goto-line)
+ (define-key map "g" 'vlf-refresh)
+ (define-key map-prefix "\C-c\C-v" map)
+ map-prefix)
"Keymap for `vlf-mode'.")
-(define-derived-mode vlf-mode special-mode "VLF"
+(define-minor-mode vlf-mode
"Mode to browse large files in."
- (setq buffer-read-only t)
- (set-buffer-modified-p nil)
- (make-local-variable 'vlf-batch-size)
- (make-local-variable 'vlf-start-pos)
- (make-local-variable 'vlf-file-size))
+ :lighter " VLF"
+ :group 'vlf
+ :keymap vlf-mode-map
+ (if vlf-mode
+ (progn
+ (set (make-local-variable 'require-final-newline) nil)
+ (add-hook 'write-file-functions 'vlf-write nil t)
+ (set (make-local-variable 'revert-buffer-function)
+ 'vlf-revert)
+ (make-local-variable 'vlf-batch-size)
+ (set (make-local-variable 'vlf-start-pos) -1)
+ (make-local-variable 'vlf-end-pos)
+ (set (make-local-variable 'vlf-file-size)
+ (vlf-get-file-size buffer-file-name))
+ (let* ((pos (position-bytes (point)))
+ (start (* (/ pos vlf-batch-size) vlf-batch-size)))
+ (goto-char (byte-to-position (- pos start)))
+ (vlf-move-to-batch start)))
+ (kill-local-variable 'revert-buffer-function)
+ (when (or (not large-file-warning-threshold)
+ (< vlf-file-size large-file-warning-threshold)
+ (y-or-n-p (format "Load whole file (%s)? "
+ (file-size-human-readable
+ vlf-file-size))))
+ (kill-local-variable 'require-final-newline)
+ (remove-hook 'write-file-functions 'vlf-write t)
+ (let ((pos (+ vlf-start-pos (position-bytes (point)))))
+ (vlf-with-undo-disabled
+ (insert-file-contents buffer-file-name t nil nil t))
+ (goto-char (byte-to-position pos)))
+ (rename-buffer (file-name-nondirectory buffer-file-name) t))))
+
+;;;###autoload
+(defun vlf (file)
+ "View Large FILE in batches.
+You can customize number of bytes displayed by customizing
+`vlf-batch-size'."
+ (interactive "fFile to open: ")
+ (with-current-buffer (generate-new-buffer "*vlf*")
+ (set-visited-file-name file)
+ (set-buffer-modified-p nil)
+ (vlf-mode 1)
+ (switch-to-buffer (current-buffer))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; integration with other packages
+
+;;;###autoload
+(defun dired-vlf ()
+ "In Dired, visit the file on this line in VLF mode."
+ (interactive)
+ (vlf (dired-get-file-for-visit)))
+
+;;;###autoload
+(eval-after-load "dired"
+ '(define-key dired-mode-map "V" 'dired-vlf))
+
+;;;###autoload
+(defadvice abort-if-file-too-large (around vlf-if-file-too-large
+ (size op-type
+ &optional filename)
+ compile activate)
+ "If file SIZE larger than `large-file-warning-threshold', \
+allow user to view file with `vlf', open it normally, or abort.
+OP-TYPE specifies the file operation being performed over FILENAME."
+ (and large-file-warning-threshold size
+ (> size large-file-warning-threshold)
+ (let ((char nil))
+ (while (not (memq (setq char
+ (read-event
+ (propertize
+ (format
+ "File %s is large (%s): \
+%s normally (o), %s with vlf (v) or abort (a)"
+ (if filename
+ (file-name-nondirectory filename)
+ "")
+ (file-size-human-readable size)
+ op-type op-type)
+ 'face 'minibuffer-prompt)))
+ '(?o ?O ?v ?V ?a ?A))))
+ (cond ((memq char '(?o ?O)))
+ ((memq char '(?v ?V))
+ (vlf filename)
+ (error ""))
+ ((memq char '(?a ?A))
+ (error "Aborted"))))))
+
+
+;; scroll auto batching
+(defadvice scroll-up (around vlf-scroll-up
+ activate compile)
+ "Slide to next batch if at end of buffer in `vlf-mode'."
+ (if (and vlf-mode (pos-visible-in-window-p (point-max)))
+ (progn (vlf-next-batch 1)
+ (goto-char (point-min)))
+ ad-do-it))
+
+(defadvice scroll-down (around vlf-scroll-down
+ activate compile)
+ "Slide to previous batch if at beginning of buffer in `vlf-mode'."
+ (if (and vlf-mode (pos-visible-in-window-p (point-min)))
+ (progn (vlf-prev-batch 1)
+ (goto-char (point-max)))
+ ad-do-it))
+
+;; non-recent Emacs
+;;;###autoload
+(unless (fboundp 'file-size-human-readable)
+ (defun file-size-human-readable (file-size)
+ "Print FILE-SIZE in MB."
+ (format "%.1fMB" (/ file-size 1048576.0))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; utilities
(defun vlf-change-batch-size (decrease)
"Change the buffer-local value of `vlf-batch-size'.
Normally, the value is doubled;
-with the prefix argument it is halved."
+with the prefix argument DECREASE it is halved."
(interactive "P")
- (or (assq 'vlf-batch-size (buffer-local-variables))
- (error "%s is not local in this buffer" 'vlf-batch-size))
- (setq vlf-batch-size
- (if decrease
- (/ vlf-batch-size 2)
- (* vlf-batch-size 2)))
- (vlf-update-buffer-name))
-
-(defun vlf-format-buffer-name ()
- "Return format for vlf buffer name."
- (format "%s(%s)[%d,%d](%d)"
- (file-name-nondirectory buffer-file-name)
- (file-size-human-readable vlf-file-size)
- vlf-start-pos vlf-end-pos vlf-batch-size))
+ (setq vlf-batch-size (if decrease
+ (/ vlf-batch-size 2)
+ (* vlf-batch-size 2)))
+ (vlf-move-to-batch vlf-start-pos))
(defun vlf-update-buffer-name ()
"Update the current buffer name."
- (rename-buffer (vlf-format-buffer-name) t))
+ (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))
+
+(defun vlf-get-file-size (file)
+ "Get size in bytes of FILE."
+ (nth 7 (file-attributes file)))
+
+(defun vlf-verify-size ()
+ "Update file size information if necessary and visited file time."
+ (unless (verify-visited-file-modtime (current-buffer))
+ (setq vlf-file-size (vlf-get-file-size buffer-file-name))
+ (set-visited-file-modtime)))
+
+(defun vlf-insert-file (&optional from-end)
+ "Insert first chunk of current file contents in current buffer.
+With FROM-END prefix, start from the back."
+ (let ((start 0)
+ (end vlf-batch-size))
+ (if from-end
+ (setq start (- vlf-file-size vlf-batch-size)
+ end vlf-file-size)
+ (setq end (min vlf-batch-size vlf-file-size)))
+ (vlf-move-to-chunk start end)))
+
+(defun vlf-beginning-of-file ()
+ "Jump to beginning of file content."
+ (interactive)
+ (vlf-insert-file))
+
+(defun vlf-end-of-file ()
+ "Jump to end of file content."
+ (interactive)
+ (vlf-insert-file t))
+
+(defun vlf-revert (&optional _ignore-auto noconfirm)
+ "Revert current chunk. Ignore _IGNORE-AUTO.
+Ask for confirmation if NOCONFIRM is nil."
+ (if (or noconfirm
+ (yes-or-no-p (format "Revert buffer from file %s? "
+ buffer-file-name)))
+ (vlf-move-to-chunk-2 vlf-start-pos vlf-end-pos)))
+
+(defun vlf-jump-to-chunk (n)
+ "Go to to chunk N."
+ (interactive "nGoto to chunk: ")
+ (vlf-move-to-batch (* (1- n) vlf-batch-size)))
+
+(defmacro vlf-with-undo-disabled (&rest body)
+ "Execute BODY with temporarily disabled undo."
+ `(let ((undo-enabled (not (eq buffer-undo-list t))))
+ (if undo-enabled
+ (buffer-disable-undo))
+ (unwind-protect (progn ,@body)
+ (if undo-enabled
+ (buffer-enable-undo)))))
+
+(defun vlf-no-modifications ()
+ "Ensure there are no buffer modifications."
+ (if (buffer-modified-p)
+ (error "Save or discard your changes first")
+ t))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; batch movement
(defun vlf-next-batch (append)
"Display the next batch of file data.
-Append to the existing buffer when the prefix argument is supplied."
- (interactive "P")
- (when (= vlf-end-pos vlf-file-size)
- (error "Already at EOF"))
- (let ((inhibit-read-only t)
- (end (min vlf-file-size (+ vlf-end-pos vlf-batch-size))))
- (goto-char (point-max))
- ;; replacing `erase-buffer' with replace arg to `insert-file-contents'
- ;; hangs emacs
- (unless append (erase-buffer))
- (insert-file-contents buffer-file-name nil vlf-end-pos end)
- (unless append
- (setq vlf-start-pos vlf-end-pos))
- (setq vlf-end-pos end)
- (set-buffer-modified-p nil)
- (vlf-update-buffer-name)))
+When prefix argument is supplied and positive
+ jump over APPEND number of batches.
+When prefix argument is negative
+ append next APPEND number of batches to the existing buffer."
+ (interactive "p")
+ (vlf-verify-size)
+ (let* ((end (min (+ vlf-end-pos (* vlf-batch-size
+ (abs append)))
+ vlf-file-size))
+ (start (if (< append 0)
+ vlf-start-pos
+ (- end vlf-batch-size))))
+ (vlf-move-to-chunk start end)))
(defun vlf-prev-batch (prepend)
"Display the previous batch of file data.
-Prepend to the existing buffer when the prefix argument is supplied."
- (interactive "P")
- (when (= vlf-start-pos 0)
- (error "Already at BOF"))
+When prefix argument is supplied and positive
+ jump over PREPEND number of batches.
+When prefix argument is negative
+ append previous PREPEND number of batches to the existing buffer."
+ (interactive "p")
+ (if (zerop vlf-start-pos)
+ (error "Already at BOF"))
+ (let* ((start (max 0 (- vlf-start-pos (* vlf-batch-size
+ (abs prepend)))))
+ (end (if (< prepend 0)
+ vlf-end-pos
+ (+ start vlf-batch-size))))
+ (vlf-move-to-chunk start end)))
+
+(defun vlf-move-to-batch (start &optional minimal)
+ "Move to batch determined by START.
+Adjust according to file start/end and show `vlf-batch-size' bytes.
+When given MINIMAL flag, skip non important operations."
+ (vlf-verify-size)
+ (let* ((start (max 0 start))
+ (end (min (+ start vlf-batch-size) vlf-file-size)))
+ (if (= vlf-file-size end) ; re-adjust start
+ (setq start (max 0 (- end vlf-batch-size))))
+ (vlf-move-to-chunk start end minimal)))
+
+(defun vlf-next-batch-from-point ()
+ "Display batch of file data starting from current point."
+ (interactive)
+ (vlf-move-to-batch (+ vlf-start-pos (position-bytes (point)) -1))
+ (goto-char (point-min)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; primitive chunk operations
+
+(defun vlf-move-to-chunk (start end &optional minimal)
+ "Move to chunk determined by START END.
+When given MINIMAL flag, skip non important operations.
+If same as current chunk is requested, do nothing."
+ (unless (and (= start vlf-start-pos)
+ (= end vlf-end-pos))
+ (vlf-verify-size)
+ (if (vlf-move-to-chunk-1 start end)
+ (or minimal (vlf-update-buffer-name)))))
+
+(defun vlf-move-to-chunk-1 (start end)
+ "Move to chunk determined by START END keeping as much edits if any.
+Return t if move hasn't been canceled."
+ (let ((modified (buffer-modified-p))
+ (start (max 0 start))
+ (end (min end vlf-file-size))
+ (edit-end (+ (position-bytes (point-max)) vlf-start-pos)))
+ (cond
+ ((and (= start vlf-start-pos) (= end edit-end))
+ (unless modified
+ (vlf-move-to-chunk-2 start end)
+ t))
+ ((or (<= edit-end start) (<= end vlf-start-pos))
+ (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)
+ t))
+ ((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))
+ (shift-start 0)
+ (shift-end 0)
+ (inhibit-read-only t))
+ (cond ((< end edit-end)
+ (let* ((del-pos (1+ (byte-to-position
+ (- end vlf-start-pos))))
+ (del-len (length (encode-coding-region
+ del-pos (point-max)
+ buffer-file-coding-system
+ t))))
+ (setq end (- vlf-end-pos del-len))
+ (vlf-with-undo-disabled
+ (delete-region del-pos (point-max)))))
+ ((< edit-end end)
+ (let ((edit-end-pos (point-max)))
+ (goto-char edit-end-pos)
+ (vlf-with-undo-disabled
+ (insert-file-contents buffer-file-name nil
+ vlf-end-pos end)
+ (setq shift-end (cdr (vlf-adjust-chunk
+ vlf-end-pos end nil t
+ edit-end-pos)))))))
+ (cond ((< vlf-start-pos start)
+ (let* ((del-pos (1+ (byte-to-position
+ (- start vlf-start-pos))))
+ (del-len (length (encode-coding-region
+ (point-min) del-pos
+ buffer-file-coding-system
+ t))))
+ (setq start (+ vlf-start-pos del-len))
+ (vlf-with-undo-disabled
+ (delete-region (point-min) del-pos))))
+ ((< start vlf-start-pos)
+ (let ((edit-end-pos (point-max)))
+ (goto-char edit-end-pos)
+ (vlf-with-undo-disabled
+ (insert-file-contents buffer-file-name nil
+ start vlf-start-pos)
+ (setq shift-start (car
+ (vlf-adjust-chunk start
+ vlf-start-pos
+ t nil
+ edit-end-pos)))
+ (goto-char (point-min))
+ (insert (delete-and-extract-region edit-end-pos
+ (point-max)))))))
+ (setq vlf-start-pos (- start shift-start)
+ vlf-end-pos (+ end shift-end))
+ (goto-char (or (byte-to-position (- pos vlf-start-pos))
+ (point-max))))
+ (set-buffer-modified-p modified)
+ t))))
+
+(defun vlf-move-to-chunk-2 (start end)
+ "Unconditionally move to chunk determined by START END."
+ (setq vlf-start-pos (max 0 start)
+ vlf-end-pos (min end vlf-file-size))
(let ((inhibit-read-only t)
- (start (max 0 (- vlf-start-pos vlf-batch-size))))
- (goto-char (point-min))
- (unless prepend (erase-buffer))
- (insert-file-contents buffer-file-name nil start vlf-start-pos)
- (unless prepend
- (setq vlf-end-pos vlf-start-pos))
- (setq vlf-start-pos start)
- (set-buffer-modified-p nil)
- (vlf-update-buffer-name)))
+ (pos (position-bytes (point))))
+ (vlf-with-undo-disabled
+ (erase-buffer)
+ (insert-file-contents buffer-file-name nil
+ vlf-start-pos vlf-end-pos)
+ (let ((shifts (vlf-adjust-chunk vlf-start-pos vlf-end-pos t
+ t)))
+ (setq vlf-start-pos (- vlf-start-pos (car shifts))
+ vlf-end-pos (+ vlf-end-pos (cdr shifts)))
+ (goto-char (or (byte-to-position (+ pos (car shifts)))
+ (point-max))))))
+ (set-buffer-modified-p nil)
+ (set-visited-file-modtime))
-(defun vlf (file)
- "View a Large File in Emacs.
-FILE is the file to open.
-Batches of the file data from FILE will be displayed in a
- read-only buffer.
-You can customize the number of bytes to
- display by customizing `vlf-batch-size'."
- (interactive "fFile to open: ")
- (with-current-buffer (generate-new-buffer "*vlf*")
- (setq buffer-file-name file
- vlf-start-pos 0
- vlf-end-pos vlf-batch-size
- vlf-file-size (nth 7 (file-attributes file)))
- (vlf-update-buffer-name)
- (insert-file-contents buffer-file-name nil
- vlf-start-pos vlf-end-pos nil)
- (vlf-mode)
- (display-buffer (current-buffer))))
+(defun vlf-adjust-chunk (start end &optional adjust-start adjust-end
+ position)
+ "Adjust chunk at absolute START to END till content can be\
+properly decoded. ADJUST-START determines if trying to prepend bytes\
+ to the beginning, ADJUST-END - append to the end.
+Use buffer POSITION as start if given.
+Return number of bytes moved back for proper decoding and number of
+bytes added to the end."
+ (let ((shift-start 0)
+ (shift-end 0))
+ (if adjust-start
+ (let ((position (or position (point-min)))
+ (chunk-size (- end start)))
+ (while (and (not (zerop start))
+ (< shift-start 4)
+ (< 4 (abs (- chunk-size
+ (length (encode-coding-region
+ position (point-max)
+ buffer-file-coding-system
+ t))))))
+ (setq shift-start (1+ shift-start)
+ start (1- start)
+ chunk-size (1+ chunk-size))
+ (delete-region position (point-max))
+ (goto-char position)
+ (insert-file-contents buffer-file-name nil start end))))
+ (if adjust-end
+ (cond ((vlf-partial-decode-shown-p) ;remove raw bytes from end
+ (goto-char (point-max))
+ (while (eq (char-charset (preceding-char)) 'eight-bit)
+ (setq shift-end (1- shift-end))
+ (delete-char -1)))
+ ((< end vlf-file-size) ;add bytes until new character is displayed
+ (let ((position (or position (point-min)))
+ (expected-size (buffer-size)))
+ (while (and (progn
+ (setq shift-end (1+ shift-end)
+ end (1+ end))
+ (delete-region position (point-max))
+ (goto-char position)
+ (insert-file-contents buffer-file-name
+ nil start end)
+ (< end vlf-file-size))
+ (= expected-size (buffer-size))))))))
+ (cons shift-start shift-end)))
+
+(defun vlf-partial-decode-shown-p ()
+ "Determine if partial decode codes are displayed.
+This seems to be the case with GNU/Emacs before 24.4."
+ (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"))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; search
+
+(defun vlf-re-search (regexp count backward batch-step)
+ "Search for REGEXP COUNT number of times forward or BACKWARD.
+BATCH-STEP is amount of overlap between successive chunks."
+ (if (<= count 0)
+ (error "Count must be positive"))
+ (let* ((case-fold-search t)
+ (match-chunk-start vlf-start-pos)
+ (match-chunk-end vlf-end-pos)
+ (match-start-pos (+ vlf-start-pos (position-bytes (point))))
+ (match-end-pos match-start-pos)
+ (to-find count)
+ (reporter (make-progress-reporter
+ (concat "Searching for " regexp "...")
+ (if backward
+ (- vlf-file-size vlf-end-pos)
+ vlf-start-pos)
+ vlf-file-size)))
+ (vlf-with-undo-disabled
+ (unwind-protect
+ (catch 'end-of-file
+ (if backward
+ (while (not (zerop to-find))
+ (cond ((re-search-backward regexp nil t)
+ (setq to-find (1- to-find)
+ match-chunk-start vlf-start-pos
+ match-chunk-end vlf-end-pos
+ match-start-pos (+ vlf-start-pos
+ (position-bytes
+ (match-beginning 0)))
+ match-end-pos (+ vlf-start-pos
+ (position-bytes
+ (match-end 0)))))
+ ((zerop vlf-start-pos)
+ (throw 'end-of-file nil))
+ (t (let ((batch-move (- vlf-start-pos
+ (- vlf-batch-size
+ batch-step))))
+ (vlf-move-to-batch
+ (if (< match-start-pos batch-move)
+ (- match-start-pos vlf-batch-size)
+ batch-move) t))
+ (goto-char (if (< match-start-pos
+ vlf-end-pos)
+ (or (byte-to-position
+ (- match-start-pos
+ vlf-start-pos))
+ (point-max))
+ (point-max)))
+ (progress-reporter-update
+ reporter (- vlf-file-size
+ vlf-start-pos)))))
+ (while (not (zerop to-find))
+ (cond ((re-search-forward regexp nil t)
+ (setq to-find (1- to-find)
+ match-chunk-start vlf-start-pos
+ match-chunk-end vlf-end-pos
+ match-start-pos (+ vlf-start-pos
+ (position-bytes
+ (match-beginning 0)))
+ match-end-pos (+ vlf-start-pos
+ (position-bytes
+ (match-end 0)))))
+ ((= vlf-end-pos vlf-file-size)
+ (throw 'end-of-file nil))
+ (t (let ((batch-move (- vlf-end-pos batch-step)))
+ (vlf-move-to-batch
+ (if (< batch-move match-end-pos)
+ match-end-pos
+ batch-move) t))
+ (goto-char (if (< vlf-start-pos match-end-pos)
+ (or (byte-to-position
+ (- match-end-pos
+ vlf-start-pos))
+ (point-min))
+ (point-min)))
+ (progress-reporter-update reporter
+ vlf-end-pos)))))
+ (progress-reporter-done reporter))
+ (set-buffer-modified-p nil)
+ (if backward
+ (vlf-goto-match match-chunk-start match-chunk-end
+ match-end-pos match-start-pos
+ count to-find)
+ (vlf-goto-match match-chunk-start match-chunk-end
+ match-start-pos match-end-pos
+ count to-find))))))
+
+(defun vlf-goto-match (match-chunk-start match-chunk-end
+ match-pos-start
+ match-pos-end
+ count to-find)
+ "Move to MATCH-CHUNK-START MATCH-CHUNK-END surrounding \
+MATCH-POS-START and MATCH-POS-END.
+According to COUNT and left TO-FIND, show if search has been
+successful. Return nil if nothing found."
+ (if (= count to-find)
+ (progn (vlf-move-to-chunk match-chunk-start match-chunk-end)
+ (goto-char (or (byte-to-position (- match-pos-start
+ vlf-start-pos))
+ (point-max)))
+ (message "Not found")
+ nil)
+ (let ((success (zerop to-find)))
+ (if success
+ (vlf-update-buffer-name)
+ (vlf-move-to-chunk match-chunk-start match-chunk-end))
+ (let* ((match-end (or (byte-to-position (- match-pos-end
+ vlf-start-pos))
+ (point-max)))
+ (overlay (make-overlay (byte-to-position
+ (- match-pos-start
+ vlf-start-pos))
+ match-end)))
+ (overlay-put overlay 'face 'match)
+ (unless success
+ (goto-char match-end)
+ (message "Moved to the %d match which is last"
+ (- count to-find)))
+ (unwind-protect (sit-for 3)
+ (delete-overlay overlay))
+ t))))
+
+(defun vlf-re-search-forward (regexp count)
+ "Search forward for REGEXP prefix COUNT number of times.
+Search is performed chunk by chunk in `vlf-batch-size' memory."
+ (interactive (if (vlf-no-modifications)
+ (list (read-regexp "Search whole file"
+ (if regexp-history
+ (car regexp-history)))
+ (or current-prefix-arg 1))))
+ (vlf-re-search regexp count nil (/ vlf-batch-size 8)))
+
+(defun vlf-re-search-backward (regexp count)
+ "Search backward for REGEXP prefix COUNT number of times.
+Search is performed chunk by chunk in `vlf-batch-size' memory."
+ (interactive (if (vlf-no-modifications)
+ (list (read-regexp "Search whole file backward"
+ (if regexp-history
+ (car regexp-history)))
+ (or current-prefix-arg 1))))
+ (vlf-re-search regexp count t (/ vlf-batch-size 8)))
+
+(defun vlf-goto-line (n)
+ "Go to line N. If N is negative, count from the end of file."
+ (interactive (if (vlf-no-modifications)
+ (list (read-number "Go to line: "))))
+ (let ((start-pos vlf-start-pos)
+ (end-pos vlf-end-pos)
+ (pos (point))
+ (success nil))
+ (unwind-protect
+ (if (< 0 n)
+ (progn (vlf-beginning-of-file)
+ (goto-char (point-min))
+ (setq success (vlf-re-search "[\n\C-m]" (1- n)
+ nil 0)))
+ (vlf-end-of-file)
+ (goto-char (point-max))
+ (setq success (vlf-re-search "[\n\C-m]" (- n) t 0)))
+ (if success
+ (message "Onto line %s" n)
+ (vlf-move-to-chunk start-pos end-pos)
+ (goto-char pos)))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; occur
+
+(defvar vlf-occur-mode-map
+ (let ((map (make-sparse-keymap)))
+ (define-key map "n" 'vlf-occur-next-match)
+ (define-key map "p" 'vlf-occur-prev-match)
+ (define-key map "\C-m" 'vlf-occur-visit)
+ (define-key map "\M-\r" 'vlf-occur-visit-new-buffer)
+ (define-key map [mouse-1] 'vlf-occur-visit)
+ (define-key map "o" 'vlf-occur-show)
+ map)
+ "Keymap for command `vlf-occur-mode'.")
+
+(define-derived-mode vlf-occur-mode special-mode "VLF[occur]"
+ "Major mode for showing occur matches of VLF opened files.")
+
+(defun vlf-occur-next-match ()
+ "Move cursor to next match."
+ (interactive)
+ (if (eq (get-char-property (point) 'face) 'match)
+ (goto-char (next-single-property-change (point) 'face)))
+ (goto-char (or (text-property-any (point) (point-max) 'face 'match)
+ (text-property-any (point-min) (point)
+ 'face 'match))))
+
+(defun vlf-occur-prev-match ()
+ "Move cursor to previous match."
+ (interactive)
+ (if (eq (get-char-property (point) 'face) 'match)
+ (goto-char (previous-single-property-change (point) 'face)))
+ (while (not (eq (get-char-property (point) 'face) 'match))
+ (goto-char (or (previous-single-property-change (point) 'face)
+ (point-max)))))
+
+(defun vlf-occur-show (&optional event)
+ "Visit current `vlf-occur' link in a vlf buffer but stay in the \
+occur buffer. If original VLF buffer has been killed,
+open new VLF session each time.
+EVENT may hold details of the invocation."
+ (interactive (list last-nonmenu-event))
+ (let ((occur-buffer (if event
+ (window-buffer (posn-window
+ (event-end event)))
+ (current-buffer))))
+ (vlf-occur-visit event)
+ (pop-to-buffer occur-buffer)))
+
+(defun vlf-occur-visit-new-buffer ()
+ "Visit `vlf-occur' link in new vlf buffer."
+ (interactive)
+ (let ((current-prefix-arg t))
+ (vlf-occur-visit)))
+
+(defun vlf-occur-visit (&optional event)
+ "Visit current `vlf-occur' link in a vlf buffer.
+With prefix argument or if original VLF buffer has been killed,
+open new VLF session.
+EVENT may hold details of the invocation."
+ (interactive (list last-nonmenu-event))
+ (when event
+ (set-buffer (window-buffer (posn-window (event-end event))))
+ (goto-char (posn-point (event-end event))))
+ (let* ((pos (point))
+ (pos-relative (- pos (line-beginning-position) 1))
+ (file (get-char-property pos 'file)))
+ (if file
+ (let ((chunk-start (get-char-property pos 'chunk-start))
+ (chunk-end (get-char-property pos 'chunk-end))
+ (vlf-buffer (get-char-property pos 'buffer))
+ (occur-buffer (current-buffer))
+ (match-pos (+ (get-char-property pos 'line-pos)
+ pos-relative)))
+ (cond (current-prefix-arg
+ (setq vlf-buffer (vlf file))
+ (switch-to-buffer occur-buffer))
+ ((not (buffer-live-p vlf-buffer))
+ (or (catch 'found
+ (dolist (buf (buffer-list))
+ (set-buffer buf)
+ (and vlf-mode (equal file buffer-file-name)
+ (setq vlf-buffer buf)
+ (throw 'found t))))
+ (setq vlf-buffer (vlf file)))
+ (switch-to-buffer occur-buffer)))
+ (pop-to-buffer vlf-buffer)
+ (vlf-move-to-chunk chunk-start chunk-end)
+ (goto-char match-pos)))))
+
+(defun vlf-occur (regexp)
+ "Make whole file occur style index for REGEXP.
+Prematurely ending indexing will still show what's found so far."
+ (interactive (list (read-regexp "List lines matching regexp"
+ (if regexp-history
+ (car regexp-history)))))
+ (if (buffer-modified-p) ;use temporary buffer not to interfere with modifications
+ (let ((vlf-buffer (current-buffer))
+ (file buffer-file-name)
+ (batch-size vlf-batch-size))
+ (with-temp-buffer
+ (setq buffer-file-name file)
+ (set-buffer-modified-p nil)
+ (set (make-local-variable 'vlf-batch-size) batch-size)
+ (vlf-mode 1)
+ (goto-char (point-min))
+ (vlf-with-undo-disabled
+ (vlf-build-occur regexp vlf-buffer))))
+ (let ((start-pos vlf-start-pos)
+ (end-pos vlf-end-pos)
+ (pos (point)))
+ (vlf-beginning-of-file)
+ (goto-char (point-min))
+ (vlf-with-undo-disabled
+ (unwind-protect (vlf-build-occur regexp (current-buffer))
+ (vlf-move-to-chunk start-pos end-pos)
+ (goto-char pos))))))
+
+(defun vlf-build-occur (regexp vlf-buffer)
+ "Build occur style index for REGEXP over VLF-BUFFER."
+ (let ((case-fold-search t)
+ (line 1)
+ (last-match-line 0)
+ (last-line-pos (point-min))
+ (file buffer-file-name)
+ (total-matches 0)
+ (match-end-pos (+ vlf-start-pos (position-bytes (point))))
+ (occur-buffer (generate-new-buffer
+ (concat "*VLF-occur " (file-name-nondirectory
+ buffer-file-name)
+ "*")))
+ (line-regexp (concat "\\(?5:[\n\C-m]\\)\\|\\(?10:"
+ regexp "\\)"))
+ (batch-step (/ vlf-batch-size 8))
+ (end-of-file nil)
+ (reporter (make-progress-reporter
+ (concat "Building index for " regexp "...")
+ vlf-start-pos vlf-file-size)))
+ (unwind-protect
+ (progn
+ (while (not end-of-file)
+ (if (re-search-forward line-regexp nil t)
+ (progn
+ (setq match-end-pos (+ vlf-start-pos
+ (position-bytes
+ (match-end 0))))
+ (if (match-string 5)
+ (setq line (1+ line) ; line detected
+ last-line-pos (point))
+ (let* ((chunk-start vlf-start-pos)
+ (chunk-end vlf-end-pos)
+ (line-pos (line-beginning-position))
+ (line-text (buffer-substring
+ line-pos (line-end-position))))
+ (with-current-buffer occur-buffer
+ (unless (= line last-match-line) ;new match line
+ (insert "\n:") ; insert line number
+ (let* ((overlay-pos (1- (point)))
+ (overlay (make-overlay
+ overlay-pos
+ (1+ overlay-pos))))
+ (overlay-put overlay 'before-string
+ (propertize
+ (number-to-string line)
+ 'face 'shadow)))
+ (insert (propertize line-text ; insert line
+ 'file file
+ 'buffer vlf-buffer
+ 'chunk-start chunk-start
+ 'chunk-end chunk-end
+ 'mouse-face '(highlight)
+ 'line-pos line-pos
+ 'help-echo
+ (format "Move to line %d"
+ line))))
+ (setq last-match-line line
+ total-matches (1+ total-matches))
+ (let ((line-start (1+
+ (line-beginning-position)))
+ (match-pos (match-beginning 10)))
+ (add-text-properties ; mark match
+ (+ line-start match-pos (- last-line-pos))
+ (+ line-start (match-end 10)
+ (- last-line-pos))
+ (list 'face 'match
+ 'help-echo
+ (format "Move to match %d"
+ total-matches))))))))
+ (setq end-of-file (= vlf-end-pos vlf-file-size))
+ (unless end-of-file
+ (let ((batch-move (- vlf-end-pos batch-step)))
+ (vlf-move-to-batch (if (< batch-move match-end-pos)
+ match-end-pos
+ batch-move) t))
+ (goto-char (if (< vlf-start-pos match-end-pos)
+ (or (byte-to-position (- match-end-pos
+ vlf-start-pos))
+ (point-min))
+ (point-min)))
+ (setq last-match-line 0
+ last-line-pos (line-beginning-position))
+ (progress-reporter-update reporter vlf-end-pos))))
+ (progress-reporter-done reporter))
+ (set-buffer-modified-p nil)
+ (if (zerop total-matches)
+ (progn (with-current-buffer occur-buffer
+ (set-buffer-modified-p nil))
+ (kill-buffer occur-buffer)
+ (message "No matches for \"%s\"" regexp))
+ (with-current-buffer occur-buffer
+ (goto-char (point-min))
+ (insert (propertize
+ (format "%d matches in %d lines for \"%s\" \
+in file: %s" total-matches line regexp file)
+ 'face 'underline))
+ (set-buffer-modified-p nil)
+ (forward-char 2)
+ (vlf-occur-mode))
+ (display-buffer occur-buffer)))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; editing
+
+(defun vlf-refresh ()
+ "Discard edit and refresh chunk from file."
+ (interactive)
+ (set-buffer-modified-p nil)
+ (vlf-move-to-chunk-2 vlf-start-pos vlf-end-pos))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; saving
+
+(defun vlf-write ()
+ "Write current chunk to file. Always return true to disable save.
+If changing size of chunk, shift remaining file content."
+ (interactive)
+ (when (and (buffer-modified-p)
+ (or (verify-visited-file-modtime (current-buffer))
+ (y-or-n-p "File has changed since visited or saved. \
+Save anyway? ")))
+ (let ((pos (point))
+ (size-change (- vlf-end-pos vlf-start-pos
+ (length (encode-coding-region
+ (point-min) (point-max)
+ buffer-file-coding-system t)))))
+ (cond ((zerop size-change)
+ (write-region nil nil buffer-file-name vlf-start-pos t))
+ ((< 0 size-change)
+ (vlf-file-shift-back size-change))
+ (t (vlf-file-shift-forward (- size-change))))
+ (vlf-move-to-chunk-2 vlf-start-pos vlf-end-pos)
+ (goto-char pos)))
+ t)
+
+(defun vlf-file-shift-back (size-change)
+ "Shift file contents SIZE-CHANGE bytes back."
+ (write-region nil nil buffer-file-name vlf-start-pos t)
+ (let ((read-start-pos vlf-end-pos)
+ (coding-system-for-write 'no-conversion)
+ (reporter (make-progress-reporter "Adjusting file content..."
+ vlf-end-pos
+ vlf-file-size)))
+ (vlf-with-undo-disabled
+ (while (vlf-shift-batch read-start-pos (- read-start-pos
+ size-change))
+ (setq read-start-pos (+ read-start-pos vlf-batch-size))
+ (progress-reporter-update reporter read-start-pos))
+ ;; pad end with space
+ (erase-buffer)
+ (vlf-verify-size)
+ (insert-char 32 size-change))
+ (write-region nil nil buffer-file-name (- vlf-file-size
+ size-change) t)
+ (progress-reporter-done reporter)))
+
+(defun vlf-shift-batch (read-pos write-pos)
+ "Read `vlf-batch-size' bytes from READ-POS and write them \
+back at WRITE-POS. Return nil if EOF is reached, t otherwise."
+ (erase-buffer)
+ (vlf-verify-size)
+ (let ((read-end (+ read-pos vlf-batch-size)))
+ (insert-file-contents-literally buffer-file-name nil
+ read-pos
+ (min vlf-file-size read-end))
+ (write-region nil nil buffer-file-name write-pos 0)
+ (< read-end vlf-file-size)))
+
+(defun vlf-file-shift-forward (size-change)
+ "Shift file contents SIZE-CHANGE bytes forward.
+Done by saving content up front and then writing previous batch."
+ (let ((read-size (max (/ vlf-batch-size 2) size-change))
+ (read-pos vlf-end-pos)
+ (write-pos vlf-start-pos)
+ (reporter (make-progress-reporter "Adjusting file content..."
+ vlf-start-pos
+ vlf-file-size)))
+ (vlf-with-undo-disabled
+ (when (vlf-shift-batches read-size read-pos write-pos t)
+ (setq write-pos (+ read-pos size-change)
+ read-pos (+ read-pos read-size))
+ (progress-reporter-update reporter write-pos)
+ (let ((coding-system-for-write 'no-conversion))
+ (while (vlf-shift-batches read-size read-pos write-pos nil)
+ (setq write-pos (+ read-pos size-change)
+ read-pos (+ read-pos read-size))
+ (progress-reporter-update reporter write-pos)))))
+ (progress-reporter-done reporter)))
+
+(defun vlf-shift-batches (read-size read-pos write-pos hide-read)
+ "Append READ-SIZE bytes of file starting at READ-POS.
+Then write initial buffer content to file at WRITE-POS.
+If HIDE-READ is non nil, temporarily hide literal read content.
+Return nil if EOF is reached, t otherwise."
+ (vlf-verify-size)
+ (let ((read-more (< read-pos vlf-file-size))
+ (start-write-pos (point-min))
+ (end-write-pos (point-max)))
+ (when read-more
+ (goto-char end-write-pos)
+ (insert-file-contents-literally buffer-file-name nil read-pos
+ (min vlf-file-size
+ (+ read-pos read-size))))
+ ;; write
+ (if hide-read ; hide literal region if user has to choose encoding
+ (narrow-to-region start-write-pos end-write-pos))
+ (write-region start-write-pos end-write-pos
+ buffer-file-name write-pos 0)
+ (delete-region start-write-pos end-write-pos)
+ (if hide-read (widen))
+ read-more))
(provide 'vlf)