-;;; vlf.el --- View Large Files
+;;; vlf.el --- View Large Files -*- lexical-binding: t -*-
-;; Copyright (C) 2006 Mathias Dahl
+;; Copyright (C) 2006, 2012-2014 Free Software Foundation, Inc.
-;; Version: 0.1.2
-;; Keywords: files, helpers, utilities
-;; Author: Mathias Dahl <mathias.dahl@gmail.com>
-;; Maintainer: Mathias Dahl
-;; URL: http://www.emacswiki.org/cgi-bin/wiki/VLF
+;; Version: 1.5
+;; Keywords: large files, utilities
+;; Maintainer: Andrey Kotlarski <m00naticus@gmail.com>
+;; Authors: 2006 Mathias Dahl <mathias.dahl@gmail.com>
+;; 2012 Sam Steingold <sds@gnu.org>
+;; 2013-2014 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
;; Boston, MA 02111-1307, USA.
;;; Commentary:
-;;
-;; After reading the Nth post on Gnu Emacs Help about Viewing Large
-;; Files in Emacs, it itched so much that I decided to make a try. It
-;; helped quite a lot when Kevin Rodgers posted a snippet on how to
-;; use `insert-file-contents' to extract part of a file. At first I
-;; made a try using head and tail and that worked too, but using
-;; internal Emacs commands is nicer. Here is the code to extract data
-;; using head and tail in case someone wanna try that out in the
-;; future:
-
-;; (defun vlf-extract-part-of-file (file from to)
-;; "Returns bytes in FILE from FROM to TO."
-;; (let ((size (vlf-file-size file)))
-;; (if (or (> from size)
-;; (> to size))
-;; (error "From or to is larger that the file size"))
-;; (with-temp-buffer
-;; (shell-command
-;; (format "head --bytes %d %s | tail --bytes %d"
-;; to file (+ (- to from) 1)) t)
-;; (buffer-substring (point-min) (point-max)))))
-
-;;; History:
-;;
-;; - Wed Jan 10 00:13:45 2007
-;;
-;; First version created and released into the wild.
-;;
-;; - Wed Jan 10 18:58:47 2007
-;;
-;; 0.1.2
-;;
-;; Added option to use external tools (head and tail) for
-;; extracting the data from the file.
-;;
-;; Refactored buffer name format code into a new function.
-;;
-;; Started to fiddle with float/integer conversions.
-;;
-
-;;; Bugs
-;;
-;; Probably some. Feel free to fix them :)
+;; This package provides the M-x vlf command, which visits part of
+;; large file without loading it entirely. The buffer uses VLF mode,
+;; which provides several commands for moving around, searching,
+;; comparing and editing selected part of file.
+;; To have it offered when opening large files:
+;; (require 'vlf-integrate)
+
+;; This package was inspired by a snippet posted by Kevin Rodgers,
+;; showing how to use `insert-file-contents' to extract part of a
+;; file.
;;; Code:
-(defgroup vlf nil
- "Browse large files in Emacs"
- :prefix "vlf-"
- :group 'files)
+(defgroup vlf nil "View Large Files in Emacs."
+ :prefix "vlf-" :group 'files)
+
+(defcustom vlf-before-batch-functions nil
+ "Hook that runs before multiple batch operations.
+One argument is supplied that specifies current action. Possible
+values are: `write', `ediff', `occur', `search', `goto-line'."
+ :group 'vlf :type 'hook)
-(defcustom vlf-batch-size 1000
- "Defines how large each batch of file data is."
- :type 'integer
- :group 'vlf)
+(defcustom vlf-after-batch-functions nil
+ "Hook that runs after multiple batch operations.
+One argument is supplied that specifies current action. Possible
+values are: `write', `ediff', `occur', `search', `goto-line'."
+ :group 'vlf :type 'hook)
-(defcustom vlf-external-extraction nil
- "How to extract the data from a file.
-`nil' means to use internal extraction, using
-`insert-file-contents'. `t' means to use external `head' and
-`tail' tools."
- :type 'boolean
- :group 'vlf)
+(require 'vlf-base)
-(defvar vlf-current-start-pos 1
- "Keeps track of file position.")
+(autoload 'vlf-write "vlf-write" "Write current chunk to file." t)
+(autoload 'vlf-re-search-forward "vlf-search"
+ "Search forward for REGEXP prefix COUNT number of times." t)
+(autoload 'vlf-re-search-backward "vlf-search"
+ "Search backward for REGEXP prefix COUNT number of times." t)
+(autoload 'vlf-goto-line "vlf-search" "Go to line." t)
+(autoload 'vlf-occur "vlf-occur"
+ "Make whole file occur style index for REGEXP." t)
+(autoload 'vlf-toggle-follow "vlf-follow"
+ "Toggle continuous chunk recenter around current point." t)
+(autoload 'vlf-stop-follow "vlf-follow" "Stop continuous recenter." t)
+(autoload 'vlf-ediff-buffers "vlf-ediff"
+ "Run batch by batch ediff over VLF buffers." t)
-(defvar vlf-current-batch-size nil
- "Keeps track of current batch size.")
+(defvar vlf-mode-map
+ (let ((map (make-sparse-keymap)))
+ (define-key map "n" 'vlf-next-batch)
+ (define-key map "p" 'vlf-prev-batch)
+ (define-key map " " '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 "e" 'vlf-ediff-buffers)
+ (define-key map "f" 'vlf-toggle-follow)
+ (define-key map "g" 'vlf-revert)
+ map)
+ "Keymap for `vlf-mode'.")
-(defvar vlf-current-file nil
- "File that is currently viewed.")
+(defvar vlf-prefix-map
+ (let ((map (make-sparse-keymap)))
+ (define-key map "\C-c\C-v" vlf-mode-map)
+ map)
+ "Prefixed keymap for `vlf-mode'.")
-(defvar vlf-current-file-size 0
- "Size of current file.")
+(define-minor-mode vlf-mode
+ "Mode to browse large files in."
+ :lighter " VLF" :group 'vlf :keymap vlf-prefix-map
+ (cond (vlf-mode
+ (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)
+ (setq vlf-file-size (vlf-get-file-size buffer-file-truename)
+ vlf-start-pos 0
+ vlf-end-pos 0)
+ (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))
+ (add-hook 'after-change-major-mode-hook 'vlf-keep-alive t t)
+ (vlf-keep-alive))
+ ((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 'revert-buffer-function)
+ (vlf-stop-follow)
+ (kill-local-variable 'require-final-newline)
+ (remove-hook 'write-file-functions 'vlf-write t)
+ (remove-hook 'after-change-major-mode-hook
+ 'vlf-keep-alive t)
+ (let ((hexl (derived-mode-p 'hexl-mode)))
+ (if hexl (hexl-mode-exit))
+ (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)))
+ (if hexl (hexl-mode)))
+ (rename-buffer (file-name-nondirectory buffer-file-name) t))
+ (t (setq vlf-mode t))))
-(defvar vlf-mode-map (make-sparse-keymap)
- "Keymap for `vlf-mode'.")
+(defun vlf-keep-alive ()
+ "Keep `vlf-mode' on major mode change."
+ (if (derived-mode-p 'hexl-mode)
+ (set (make-local-variable 'revert-buffer-function) 'vlf-revert))
+ (setq vlf-mode t))
+
+;;;###autoload
+(defun vlf (file)
+ "View Large FILE in batches.
+You can customize number of bytes displayed by customizing
+`vlf-batch-size'.
+Return newly created buffer."
+ (interactive "fFile to open: ")
+ (let ((vlf-buffer (generate-new-buffer "*vlf*")))
+ (set-buffer vlf-buffer)
+ (set-visited-file-name file)
+ (set-buffer-modified-p nil)
+ (vlf-mode 1)
+ (switch-to-buffer vlf-buffer)
+ vlf-buffer))
+
+(defun vlf-next-batch (append)
+ "Display the next batch of file data.
+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.
+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)))
+
+;; 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))
+
+;; hexl mode integration
+(defun vlf-hexl-before (&optional operation)
+ "Temporarily disable `hexl-mode' for OPERATION."
+ (when (derived-mode-p 'hexl-mode)
+ (hexl-mode-exit)
+ (set (make-local-variable 'vlf-restore-hexl-mode) operation)))
+
+(defun vlf-hexl-after (&optional operation)
+ "Re-enable `hexl-mode' if active before OPERATION."
+ (when (and (boundp 'vlf-restore-hexl-mode)
+ (eq vlf-restore-hexl-mode operation))
+ (hexl-mode)
+ (kill-local-variable 'vlf-restore-hexl-mode)))
+
+(add-hook 'vlf-before-batch-functions 'vlf-hexl-before)
+(add-hook 'vlf-after-batch-functions 'vlf-hexl-after)
+(add-hook 'vlf-before-chunk-update 'vlf-hexl-before)
+(add-hook 'vlf-after-chunk-update 'vlf-hexl-after)
-(defun vlf-define-keymap ()
- "Define keymap for `vlf-mode'."
- (define-key vlf-mode-map [next] 'vlf-next)
- (define-key vlf-mode-map [prior] 'vlf-prev)
- (define-key vlf-mode-map "q" 'vlf-quit))
-
-(define-derived-mode vlf-mode
- fundamental-mode "vlf-mode"
- "Mode to browse large files in.
-See `vlf' for details."
- (vlf-define-keymap)
- (toggle-read-only 1)
- (message "vlf-mode enabled"))
-
-(defun vlf-file-size (file)
- "Get size of FILE."
- (nth 7 (file-attributes file)))
-
-(defun vlf-quit ()
- "Quit vlf."
+(eval-after-load "hexl"
+ '(progn
+ (defadvice hexl-save-buffer (around vlf-hexl-save
+ activate compile)
+ "Prevent hexl save if `vlf-mode' is active."
+ (if vlf-mode
+ (vlf-write)
+ ad-do-it))
+
+ (defadvice hexl-scroll-up (around vlf-hexl-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))
+ (or (not (numberp arg)) (< 0 arg)))
+ (progn (vlf-next-batch 1)
+ (goto-char (point-min)))
+ ad-do-it))
+
+ (defadvice hexl-scroll-down (around vlf-hexl-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))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;; 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 DECREASE it is halved."
+ (interactive "P")
+ (vlf-set-batch-size (if decrease (/ vlf-batch-size 2)
+ (* vlf-batch-size 2))))
+
+(defun vlf-set-batch-size (size)
+ "Set batch to SIZE bytes and update chunk."
+ (interactive (list (read-number "Size in bytes: " vlf-batch-size)))
+ (setq vlf-batch-size size)
+ (vlf-move-to-batch vlf-start-pos))
+
+(defun vlf-beginning-of-file ()
+ "Jump to beginning of file content."
(interactive)
- (kill-buffer (current-buffer)))
-
-(defun vlf-extract-with-head-and-tail (file from to)
- "Returns bytes in FILE from FROM to TO."
- (let ((size (vlf-file-size file)))
- (if (or (> from size)
- (> to size))
- (error "From or to is larger that the file size"))
- (with-temp-buffer
- (shell-command
- (format "head --bytes %.0f \"%s\" | tail --bytes %.0f"
- (float to) (expand-file-name file)
- (float (+ (- to from) 1))) t)
- (buffer-substring (point-min) (point-max)))))
-
-(defun vlf-insert-batch ()
- "Insert current batch of data."
- (let* ((beg (1- vlf-current-start-pos))
- (end (+ beg vlf-current-batch-size)))
- (if vlf-external-extraction
- (insert
- (vlf-extract-with-head-and-tail
- vlf-current-file (1+ beg) end))
- (insert-file-contents
- vlf-current-file nil
- (floor beg) (floor end)))))
-
-(defun vlf-format-buffer-name ()
- "Return format for vlf buffer name."
- (format "%s[%.0f,%.0f(%.0f)]"
- (file-name-nondirectory vlf-current-file)
- vlf-current-start-pos
- (1- (+ vlf-current-start-pos
- vlf-current-batch-size))
- vlf-current-file-size))
-
-(defun vlf-next ()
- "Display the next batch of file data."
+ (vlf-move-to-batch 0))
+
+(defun vlf-end-of-file ()
+ "Jump to end of file content."
(interactive)
- (let ((inhibit-read-only t)
- left next-start-pos
- (size (vlf-file-size vlf-current-file)))
- (setq next-start-pos (float (+ vlf-current-start-pos
- vlf-batch-size)))
- (if (> next-start-pos size)
- (message "End of file")
- (setq vlf-current-batch-size
- vlf-batch-size
- vlf-current-start-pos next-start-pos
- left (1+ (- size vlf-current-start-pos)))
- (if (< left vlf-current-batch-size)
- (setq vlf-current-batch-size left))
- (erase-buffer)
- (vlf-insert-batch)
- (rename-buffer
- (vlf-format-buffer-name)))))
-
-(defun vlf-prev ()
- "Display the previous batch of file data."
+ (vlf-verify-size)
+ (vlf-move-to-batch vlf-file-size))
+
+(defun vlf-revert (&optional _ignore-auto noconfirm)
+ "Revert current chunk. Ignore _IGNORE-AUTO.
+Ask for confirmation if NOCONFIRM is nil."
(interactive)
- (if (= 1 vlf-current-start-pos)
- (message "At beginning of file")
- (let ((inhibit-read-only t))
- (erase-buffer)
- (setq vlf-current-start-pos (- vlf-current-start-pos
- vlf-batch-size)
- vlf-current-batch-size vlf-batch-size)
- (vlf-insert-batch)
- (rename-buffer
- (vlf-format-buffer-name)))))
+ (when (or noconfirm
+ (yes-or-no-p (format "Revert buffer from file %s? "
+ buffer-file-name)))
+ (set-buffer-modified-p nil)
+ (vlf-move-to-chunk-2 vlf-start-pos vlf-end-pos)))
-(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 amount of bytes to
-display by customizing `vlf-batch-size'."
- (interactive "fFile to open: ")
- (setq vlf-current-file file
- vlf-current-start-pos 1
- vlf-current-file-size (vlf-file-size file)
- vlf-current-batch-size
- (1- (+ vlf-current-start-pos
- vlf-batch-size)))
- (switch-to-buffer
- (generate-new-buffer (vlf-format-buffer-name)))
- (erase-buffer)
- (vlf-insert-batch)
- (vlf-mode))
+(defun vlf-jump-to-chunk (n)
+ "Go to to chunk N."
+ (interactive "nGoto to chunk: ")
+ (vlf-move-to-batch (* (1- n) vlf-batch-size)))
+
+(defun vlf-no-modifications ()
+ "Ensure there are no buffer modifications."
+ (if (buffer-modified-p)
+ (error "Save or discard your changes first")
+ t))
+
+(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)
+ (let ((start (+ vlf-start-pos (position-bytes (point)) -1)))
+ (vlf-move-to-chunk start (+ start vlf-batch-size)))
+ (goto-char (point-min)))
(provide 'vlf)