[elpa] externals/vlf 02a37c4 123/310: Merge branch 'master' into chunk-opt2

[Stefan Monnier]

branch: externals/vlf
commit 02a37c41921825c174a48baf51fa18d87835aae3
Author: Andrey Kotlarski <m00naticus@gmail.com>
Commit: Andrey Kotlarski <m00naticus@gmail.com>

    Merge branch 'master' into chunk-opt2
---
 README.org |  20 ++++++------
 vlfi.el    | 104 ++++++++++++++++++++++++++++++++++---------------------------
 2 files changed, 67 insertions(+), 57 deletions(-)

diff --git a/README.org b/README.org
index 9dae369..d83962f 100644
--- a/README.org
+++ b/README.org
@@ -1,13 +1,12 @@
-* View Large Files Improved
+* View Large Files
 
 An Emacs mode that allows viewing, editing and searching in large
 files in chunks.  Batch size can be adjusted on the fly and bounds the
 memory that is to be used for operations on the file.
 
-This mode builds on the bare bones GNU ELPA vlf.el.  It adds the
-following improvements:
+This is development version of the GNU ELPA 
[[http://elpa.gnu.org/packages/vlf][vlf.el]] package.  Here's
+what it does in a nutshell:
 
-- proper dealing with Unicode
 - regular expression search on whole file (in constant memory
   determined by current batch size)
 - chunk editing (if size has changed, saving is done in constant
@@ -18,8 +17,7 @@ following improvements:
 - newly added content is acknowledged if file has changed size
   meanwhile
 - automatic scrolling of batches
-- VLFI is added as an option when opening large files and given dired
-  key-binding
+- VLFI is added as an option when opening large files
 
 GNU Emacs 23 and 24 are supported.
 
@@ -48,15 +46,15 @@ integer value), VLFI will probably not quite work.
 VLFI is derived from special-mode and keeps all its properties.  For
 example you can directly press digits to enter prefix arguments.
 
-** Changing major mode
+** Change major mode
 
-You can (temporarily) change major mode to whatever you like (for
-example hexl-mode).  Saving will insert contents as intended.  You can
-return to *vlfi-mode* too.
+You can change major mode to whatever you like (for example
+hexl-mode).  Saving will insert contents as intended.  You can return
+to *vlfi-mode* too.
 
 * Detail usage
 
-** Controlling batch size
+** Control batch size
 
 *+* and *-* control current batch size by factors of 2.
 
diff --git a/vlfi.el b/vlfi.el
index 6df9d94..5c8ddca 100644
--- a/vlfi.el
+++ b/vlfi.el
@@ -1,12 +1,14 @@
-;;; vlfi.el --- View Large Files Improved  -*- lexical-binding: t -*-
+;;; vlfi.el --- View Large Files  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 2006, 2012, 2013  Free Software Foundation, Inc.
 
-;; Version: 0.8
+;; Version: 0.9.1
 ;; 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
@@ -30,7 +32,9 @@
 ;; The buffer uses VLFI mode, which defines several commands for
 ;; moving around, searching and editing selected part of file.
 
-;; This package is upgraded version of the vlf.el package.
+;; 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:
 
@@ -49,6 +53,7 @@
   "Absolute position of the visible chunk start.")
 (defvar vlfi-end-pos 0 "Absolute position of the visible chunk end.")
 (defvar vlfi-file-size 0 "Total size of presented file.")
+(defvar vlfi-encode-size 0 "Size in bytes of current batch decoded.")
 
 (defvar vlfi-mode-map
   (let ((map (make-sparse-keymap)))
@@ -70,23 +75,25 @@
     map)
   "Keymap for `vlfi-mode'.")
 
+(put 'vlfi-batch-size 'permanent-local t)
+(put 'vlfi-start-pos 'permanent-local t)
+(put 'vlfi-end-pos 'permanent-local t)
+(put 'vlfi-file-size 'permanent-local t)
+(put 'vlfi-encode-size 'permanent-local t)
+
 (define-derived-mode vlfi-mode special-mode "VLFI"
   "Mode to browse large files in."
   (setq buffer-read-only t)
   (set-buffer-modified-p nil)
   (buffer-disable-undo)
-  (make-local-variable 'write-file-functions)
-  (add-hook 'write-file-functions 'vlfi-write)
+  (add-hook 'write-file-functions 'vlfi-write nil t)
   (make-local-variable 'revert-buffer-function)
   (setq revert-buffer-function 'vlfi-revert)
   (make-local-variable 'vlfi-batch-size)
-  (put 'vlfi-batch-size 'permanent-local t)
   (make-local-variable 'vlfi-start-pos)
-  (put 'vlfi-start-pos 'permanent-local t)
   (make-local-variable 'vlfi-end-pos)
-  (put 'vlfi-end-pos 'permanent-local t)
   (make-local-variable 'vlfi-file-size)
-  (put 'vlfi-file-size 'permanent-local t))
+  (make-local-variable 'vlfi-encode-size))
 
 ;;;###autoload
 (defun vlfi (file)
@@ -96,9 +103,9 @@ buffer.  You can customize number of bytes displayed by 
customizing
 `vlfi-batch-size'."
   (interactive "fFile to open: ")
   (with-current-buffer (generate-new-buffer "*vlfi*")
+    (set-visited-file-name file)
     (vlfi-mode)
-    (setq buffer-file-name file
-          vlfi-file-size (vlfi-get-file-size file))
+    (setq vlfi-file-size (vlfi-get-file-size buffer-file-name))
     (vlfi-insert-file)
     (switch-to-buffer (current-buffer))))
 
@@ -116,9 +123,12 @@ buffer.  You can customize number of bytes displayed by 
customizing
   '(define-key dired-mode-map "V" 'dired-vlfi))
 
 ;;;###autoload
-(defun vlfi-if-file-too-large (size op-type &optional filename)
+(defadvice abort-if-file-too-large (around vlfi-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 `vlfi', open it normally or abort.
+allow user to view file with `vlfi', 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)
@@ -143,15 +153,12 @@ OP-TYPE specifies the file operation being performed over 
FILENAME."
                ((memq char '(?a ?A))
                 (error "Aborted"))))))
 
-;; hijack `abort-if-file-too-large'
-;;;###autoload
-(fset 'abort-if-file-too-large 'vlfi-if-file-too-large)
 
 ;; scroll auto batching
 (defadvice scroll-up (around vlfi-scroll-up
                              activate compile)
   "Slide to next batch if at end of buffer in `vlfi-mode'."
-  (if (and (eq major-mode 'vlfi-mode)
+  (if (and (derived-mode-p 'vlfi-mode)
            (eobp))
       (progn (vlfi-next-batch 1)
              (goto-char (point-min)))
@@ -160,7 +167,7 @@ OP-TYPE specifies the file operation being performed over 
FILENAME."
 (defadvice scroll-down (around vlfi-scroll-down
                                activate compile)
   "Slide to previous batch if at beginning of buffer  in `vlfi-mode'."
-  (if (and (eq major-mode 'vlfi-mode)
+  (if (and (derived-mode-p 'vlfi-mode)
            (bobp))
       (progn (vlfi-prev-batch 1)
              (goto-char (point-max)))
@@ -180,8 +187,6 @@ OP-TYPE specifies the file operation being performed over 
FILENAME."
 Normally, the value is doubled;
 with the prefix argument DECREASE it is halved."
   (interactive "P")
-  (or (assq 'vlfi-batch-size (buffer-local-variables))
-      (error "%s is not local in this buffer" 'vlfi-batch-size))
   (setq vlfi-batch-size (if decrease
                             (/ vlfi-batch-size 2)
                           (* vlfi-batch-size 2)))
@@ -204,6 +209,12 @@ with the prefix argument DECREASE it is halved."
   "Get size in bytes of FILE."
   (nth 7 (file-attributes file)))
 
+(defun vlfi-verify-size ()
+  "Update file size information if necessary and visited file time."
+  (unless (verify-visited-file-modtime (current-buffer))
+    (setq vlfi-file-size (vlfi-get-file-size buffer-file-name))
+    (set-visited-file-modtime)))
+
 (defun vlfi-insert-file (&optional from-end)
   "Insert first chunk of current file contents in current buffer.
 With FROM-END prefix, start from the back."
@@ -225,13 +236,12 @@ With FROM-END prefix, start from the back."
   (interactive)
   (vlfi-insert-file t))
 
-(defun vlfi-revert (&optional ignore-auto noconfirm)
-  "Revert current chunk.  Ignore IGNORE-AUTO.
+(defun vlfi-revert (&optional _ignore-auto noconfirm)
+  "Revert current chunk.  Ignore _IGNORE-AUTO.
 Ask for confirmation if NOCONFIRM is nil."
-  (ignore ignore-auto)
-  (or noconfirm
-      (yes-or-no-p (format "Revert buffer from file %s? "
-                           buffer-file-name))
+  (if (or noconfirm
+          (yes-or-no-p (format "Revert buffer from file %s? "
+                               buffer-file-name)))
       (vlfi-move-to-chunk vlfi-start-pos vlfi-end-pos)))
 
 (defun vlfi-jump-to-chunk (n)
@@ -249,8 +259,7 @@ When prefix argument is supplied and positive
 When prefix argument is negative
  append next APPEND number of batches to the existing buffer."
   (interactive "p")
-  (or (verify-visited-file-modtime (current-buffer))
-      (setq vlfi-file-size (vlfi-get-file-size buffer-file-name)))
+  (vlfi-verify-size)
   (let* ((end (min (+ vlfi-end-pos (* vlfi-batch-size
                                       (abs append)))
                    vlfi-file-size))
@@ -279,8 +288,7 @@ When prefix argument is negative
   "Move to batch determined by START.
 Adjust according to file start/end and show `vlfi-batch-size' bytes.
 When given MINIMAL flag, skip non important operations."
-  (or (verify-visited-file-modtime (current-buffer))
-      (setq vlfi-file-size (vlfi-get-file-size buffer-file-name)))
+  (vlfi-verify-size)
   (let ((start (max 0 start))
         (end (min (+ vlfi-start-pos vlfi-batch-size)
                   vlfi-file-size)))
@@ -417,10 +425,13 @@ Return cons \(success-status . 
number-of-bytes-moved-back\)."
 
 (defun vlfi-decode-status (size)
   "Check if decoding followed by encoding results in SIZE bytes."
-  (= size (length (encode-coding-string
-                   (decode-coding-region (point-min) (point-max)
-                                         buffer-file-coding-system t)
-                   buffer-file-coding-system t))))
+  (< (abs (- size (setq vlfi-encode-size
+                          (length (encode-coding-string
+                                   (decode-coding-region
+                                    (point-min) (point-max)
+                                    buffer-file-coding-system t)
+                                   buffer-file-coding-system t)))))
+     4))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; search
@@ -666,9 +677,9 @@ Prematurely ending indexing will still show what's found so 
far."
         (pos (point)))
     (vlfi-beginning-of-file)
     (goto-char (point-min))
-    (vlfi-build-occur regexp)
-    (vlfi-move-to-chunk start-pos end-pos)
-    (goto-char pos)))
+    (unwind-protect (vlfi-build-occur regexp)
+      (vlfi-move-to-chunk start-pos end-pos)
+      (goto-char pos))))
 
 (defun vlfi-build-occur (regexp)
   "Build occur style index for REGEXP."
@@ -804,17 +815,19 @@ or \\[vlfi-discard-edit] to discard changes.")))
 
 (defun vlfi-write ()
   "Write current chunk to file.  Always return true to disable save.
-If changing size of chunk shift remaining file content."
+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 (- vlfi-end-pos vlfi-start-pos
-                          (length (encode-coding-region
-                                   (point-min) (point-max)
-                                   buffer-file-coding-system t)))))
+          (size-change (- vlfi-encode-size
+                          (setq vlfi-encode-size
+                                (length (encode-coding-region
+                                         (point-min) (point-max)
+                                         buffer-file-coding-system
+                                         t))))))
       (cond ((zerop size-change)
              (write-region nil nil buffer-file-name vlfi-start-pos t))
             ((< 0 size-change)
@@ -840,6 +853,7 @@ Save anyway? ")))
       (progress-reporter-update reporter read-start-pos))
     ;; pad end with space
     (erase-buffer)
+    (vlfi-verify-size)
     (insert-char 32 size-change)
     (write-region nil nil buffer-file-name (- vlfi-file-size
                                               size-change) t)
@@ -849,8 +863,7 @@ Save anyway? ")))
   "Read `vlfi-batch-size' bytes from READ-POS and write them \
 back at WRITE-POS.  Return nil if EOF is reached, t otherwise."
   (erase-buffer)
-  (or (verify-visited-file-modtime (current-buffer))
-      (setq vlfi-file-size (vlfi-get-file-size buffer-file-name)))
+  (vlfi-verify-size)
   (let ((read-end (+ read-pos vlfi-batch-size)))
     (insert-file-contents-literally buffer-file-name nil
                                     read-pos
@@ -884,8 +897,7 @@ Done by saving content up front and then writing previous 
batch."
 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."
-  (or (verify-visited-file-modtime (current-buffer))
-      (setq vlfi-file-size (vlfi-get-file-size buffer-file-name)))
+  (vlfi-verify-size)
   (let ((read-more (< read-pos vlfi-file-size))
         (start-write-pos (point-min))
         (end-write-pos (point-max)))