Simplify detection of buffer size change.

2025-10-31 15:11:47 +00:00 · 2013-04-13 01:29:12 +03:00
parent 8787186619
commit 8f6299c6c2
1 changed files with 169 additions and 173 deletions
--- a/vlfi.el
+++ b/vlfi.el
@@ -50,7 +50,6 @@
 (defvar vlfi-end-pos vlfi-batch-size
  "Absolute position of the visible chunk end.")
 (defvar vlfi-file-size 0 "Total size of presented file.")
-(defvar vlfi-buffer-size 0 "Buffer size of current chunk.")

 (defvar vlfi-mode-map
  (let ((map (make-sparse-keymap)))
@@ -59,8 +58,8 @@
    (define-key map "+" 'vlfi-change-batch-size)
    (define-key map "-"
      (lambda () "Decrease vlfi batch size by factor of 2."
-        (interactive)
-        (vlfi-change-batch-size t)))
+	(interactive)
+	(vlfi-change-batch-size t)))
    (define-key map "s" 'vlfi-re-search-forward)
    (define-key map "r" 'vlfi-re-search-backward)
    (define-key map "[" 'vlfi-beginning-of-file)
@@ -83,9 +82,7 @@
  (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-buffer-size)
-  (put 'vlfi-buffer-size 'permanent-local t))
+  (put 'vlfi-file-size 'permanent-local t))

 (defun vlfi-change-batch-size (decrease)
  "Change the buffer-local value of `vlfi-batch-size'.
@@ -95,18 +92,18 @@ with the prefix argument DECREASE it is halved."
  (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)))
+			    (/ vlfi-batch-size 2)
+			  (* vlfi-batch-size 2)))
  (vlfi-move-to-batch vlfi-start-pos))

 (defun vlfi-format-buffer-name ()
  "Return format for vlfi buffer name."
  (format "%s(%s)[%d/%d](%d)"
-          (file-name-nondirectory buffer-file-name)
-          (file-size-human-readable vlfi-file-size)
-          (/ vlfi-end-pos vlfi-batch-size)
-          (/ vlfi-file-size vlfi-batch-size)
-          vlfi-batch-size))
+	  (file-name-nondirectory buffer-file-name)
+	  (file-size-human-readable vlfi-file-size)
+	  (/ vlfi-end-pos vlfi-batch-size)
+	  (/ vlfi-file-size vlfi-batch-size)
+	  vlfi-batch-size))

 (defun vlfi-update-buffer-name ()
  "Update the current buffer name."
@@ -120,28 +117,26 @@ When prefix argument is negative
 append next APPEND number of batches to the existing buffer."
  (interactive "p")
  (let ((end (+ vlfi-end-pos (* vlfi-batch-size
-                                (abs append)))))
+				(abs append)))))
    (when (< vlfi-file-size end)        ; re-check file size
      (setq vlfi-file-size (nth 7 (file-attributes buffer-file-name)))
      (cond ((= vlfi-end-pos vlfi-file-size)
-             (error "Already at EOF"))
-            ((< vlfi-file-size end)
-             (setq end vlfi-file-size))))
+	     (error "Already at EOF"))
+	    ((< vlfi-file-size end)
+	     (setq end vlfi-file-size))))
    (let ((inhibit-read-only t)
-          (do-append (< append 0))
-          (pos (point)))
+	  (do-append (< append 0))
+	  (pos (point)))
      (if do-append
-          (goto-char (point-max))
-        (setq vlfi-start-pos (- end vlfi-batch-size))
-        (erase-buffer))
-      (insert-file-contents buffer-file-name nil
-                            (if do-append
-                                vlfi-end-pos
-                              vlfi-start-pos)
-                            end)
+	  (goto-char (point-max))
+	(setq vlfi-start-pos (- end vlfi-batch-size))
+	(erase-buffer))
+      (insert-file-contents buffer-file-name nil (if do-append
+						     vlfi-end-pos
+						   vlfi-start-pos)
+			    end)
      (goto-char pos))
-    (setq vlfi-end-pos end
-          vlfi-buffer-size (buffer-size)))
+    (setq vlfi-end-pos end))
  (set-visited-file-modtime)
  (set-buffer-modified-p nil)
  (vlfi-update-buffer-name))
@@ -156,21 +151,20 @@ When prefix argument is negative
  (if (zerop vlfi-start-pos)
      (error "Already at BOF"))
  (let ((inhibit-read-only t)
-        (start (max 0 (- vlfi-start-pos (* vlfi-batch-size
-                                           (abs prepend)))))
-        (do-prepend (< prepend 0))
-        (pos (- (point-max) (point))))
+	(start (max 0 (- vlfi-start-pos (* vlfi-batch-size
+					   (abs prepend)))))
+	(do-prepend (< prepend 0))
+	(pos (- (point-max) (point))))
    (if do-prepend
-        (goto-char (point-min))
+	(goto-char (point-min))
      (setq vlfi-end-pos (+ start vlfi-batch-size))
      (erase-buffer))
    (insert-file-contents buffer-file-name nil start
-                          (if do-prepend
-                              vlfi-start-pos
-                            vlfi-end-pos))
+			  (if do-prepend
+			      vlfi-start-pos
+			    vlfi-end-pos))
    (goto-char (- (point-max) pos))
-    (setq vlfi-start-pos start
-          vlfi-buffer-size (buffer-size)))
+    (setq vlfi-start-pos start))
  (set-visited-file-modtime)
  (set-buffer-modified-p nil)
  (vlfi-update-buffer-name))
@@ -179,19 +173,18 @@ When prefix argument is negative
  "Move to batch determined by START.
 Adjust according to file start/end and show `vlfi-batch-size' bytes."
  (setq vlfi-start-pos (max 0 start)
-        vlfi-end-pos (+ vlfi-start-pos vlfi-batch-size))
+	vlfi-end-pos (+ vlfi-start-pos vlfi-batch-size))
  (if (< vlfi-file-size vlfi-end-pos)   ; re-check file size
      (setq vlfi-file-size
-            (nth 7 (file-attributes buffer-file-name))
-            vlfi-end-pos (min vlfi-end-pos vlfi-file-size)
-            vlfi-start-pos (max 0 (- vlfi-end-pos vlfi-batch-size))))
+	    (nth 7 (file-attributes buffer-file-name))
+	    vlfi-end-pos (min vlfi-end-pos vlfi-file-size)
+	    vlfi-start-pos (max 0 (- vlfi-end-pos vlfi-batch-size))))
  (let ((inhibit-read-only t)
-        (pos (point)))
+	(pos (point)))
    (erase-buffer)
    (insert-file-contents buffer-file-name nil
-                          vlfi-start-pos vlfi-end-pos)
+			  vlfi-start-pos vlfi-end-pos)
    (goto-char pos))
-  (setq vlfi-buffer-size (buffer-size))
  (set-visited-file-modtime)
  (set-buffer-modified-p nil)
  (vlfi-update-buffer-name))
@@ -200,16 +193,15 @@ Adjust according to file start/end and show `vlfi-batch-size' bytes."
  "Move to chunk determined by START END."
  (if (< vlfi-file-size end)            ; re-check file size
      (setq vlfi-file-size (nth 7
-                                (file-attributes buffer-file-name))))
+				(file-attributes buffer-file-name))))
  (setq vlfi-start-pos (max 0 start)
-        vlfi-end-pos (min end vlfi-file-size))
+	vlfi-end-pos (min end vlfi-file-size))
  (let ((inhibit-read-only t)
-        (pos (point)))
+	(pos (point)))
    (erase-buffer)
    (insert-file-contents buffer-file-name nil
-                          vlfi-start-pos vlfi-end-pos)
+			  vlfi-start-pos vlfi-end-pos)
    (goto-char pos))
-  (setq vlfi-buffer-size (buffer-size))
  (set-visited-file-modtime)
  (set-buffer-modified-p nil)
  (vlfi-update-buffer-name))
@@ -219,9 +211,9 @@ Adjust according to file start/end and show `vlfi-batch-size' bytes."
 With FROM-END prefix, start from the back."
  (if from-end
      (setq vlfi-start-pos (max 0 (- vlfi-file-size vlfi-batch-size))
-            vlfi-end-pos vlfi-file-size)
+	    vlfi-end-pos vlfi-file-size)
    (setq vlfi-start-pos 0
-          vlfi-end-pos (min vlfi-batch-size vlfi-file-size)))
+	  vlfi-end-pos (min vlfi-batch-size vlfi-file-size)))
  (vlfi-move-to-chunk vlfi-start-pos vlfi-end-pos))

 (defun vlfi-beginning-of-file ()
@@ -243,7 +235,7 @@ buffer.  You can customize number of bytes displayed by customizing
  (interactive "fFile to open: \nP")
  (with-current-buffer (generate-new-buffer "*vlfi*")
    (setq buffer-file-name file
-          vlfi-file-size (nth 7 (file-attributes file)))
+	  vlfi-file-size (nth 7 (file-attributes file)))
    (vlfi-insert-file from-end)
    (vlfi-mode)
    (switch-to-buffer (current-buffer))))
@@ -272,25 +264,25 @@ 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): \
+	 (while (not (memq (setq char
+				 (read-event
+				  (propertize
+				   (format
+				    "File %s is large (%s): \
 %s normally (o), %s with vlfi (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))
-                (vlfi filename nil)
-                (error ""))
-               ((memq char '(?a ?A))
-                (error "Aborted"))))))
+				    (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))
+		(vlfi filename nil)
+		(error ""))
+	       ((memq char '(?a ?A))
+		(error "Aborted"))))))

 ;;; hijack `abort-if-file-too-large'
 ;;;###autoload
@@ -300,66 +292,66 @@ OP-TYPE specifies the file operation being performed over FILENAME."
 (defun vlfi-re-search (regexp count backward)
  "Search for REGEXP COUNT number of times forward or BACKWARD."
  (let* ((match-start-pos (+ vlfi-start-pos (point)))
-         (match-end-pos match-start-pos)
-         (to-find count)
-         (search-reporter (make-progress-reporter
-                           (concat "Searching for " regexp)
-                           (if backward
-                               (- vlfi-file-size vlfi-end-pos)
-                             vlfi-start-pos)
-                           vlfi-file-size))
-         (batch-step (/ vlfi-batch-size 8))) ; amount of chunk overlap
+	 (match-end-pos match-start-pos)
+	 (to-find count)
+	 (search-reporter (make-progress-reporter
+			   (concat "Searching for " regexp)
+			   (if backward
+			       (- vlfi-file-size vlfi-end-pos)
+			     vlfi-start-pos)
+			   vlfi-file-size))
+	 (batch-step (/ vlfi-batch-size 8))) ; amount of chunk overlap
    (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-start-pos (+ vlfi-start-pos
-                                                (match-beginning 0))
-                             match-end-pos (+ vlfi-start-pos
-                                              (match-end 0))))
-                      ((zerop vlfi-start-pos)
-                       (throw 'end-of-file nil))
-                      (t (let ((batch-move (- vlfi-start-pos
-                                              (- vlfi-batch-size
-                                                 batch-step))))
-                           (vlfi-move-to-batch
-                            (if (< match-start-pos batch-move)
-                                (- match-start-pos vlfi-batch-size)
-                              batch-move)))
-                         (goto-char (if (< match-start-pos
-                                           vlfi-end-pos)
-                                        (- match-start-pos
-                                           vlfi-start-pos)
-                                      (point-max)))
-                         (progress-reporter-update search-reporter
-                                                   vlfi-start-pos))))
-            (while (not (zerop to-find))
-              (cond ((re-search-forward regexp nil t)
-                     (setq to-find (1- to-find)
-                           match-start-pos (+ vlfi-start-pos
-                                              (match-beginning 0))
-                           match-end-pos (+ vlfi-start-pos
-                                            (match-end 0))))
-                    ((= vlfi-end-pos vlfi-file-size)
-                     (throw 'end-of-file nil))
-                    (t (let ((batch-move (- vlfi-end-pos batch-step)))
-                         (vlfi-move-to-batch
-                          (if (< batch-move match-end-pos)
-                              match-end-pos
-                            batch-move)))
-                       (goto-char (if (< vlfi-start-pos match-end-pos)
-                                      (- match-end-pos vlfi-start-pos)
-                                    (point-min)))
-                       (progress-reporter-update search-reporter
-                                                 vlfi-end-pos)))))
-          (progress-reporter-done search-reporter))
+	(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-start-pos (+ vlfi-start-pos
+						(match-beginning 0))
+			     match-end-pos (+ vlfi-start-pos
+					      (match-end 0))))
+		      ((zerop vlfi-start-pos)
+		       (throw 'end-of-file nil))
+		      (t (let ((batch-move (- vlfi-start-pos
+					      (- vlfi-batch-size
+						 batch-step))))
+			   (vlfi-move-to-batch
+			    (if (< match-start-pos batch-move)
+				(- match-start-pos vlfi-batch-size)
+			      batch-move)))
+			 (goto-char (if (< match-start-pos
+					   vlfi-end-pos)
+					(- match-start-pos
+					   vlfi-start-pos)
+				      (point-max)))
+			 (progress-reporter-update search-reporter
+						   vlfi-start-pos))))
+	    (while (not (zerop to-find))
+	      (cond ((re-search-forward regexp nil t)
+		     (setq to-find (1- to-find)
+			   match-start-pos (+ vlfi-start-pos
+					      (match-beginning 0))
+			   match-end-pos (+ vlfi-start-pos
+					    (match-end 0))))
+		    ((= vlfi-end-pos vlfi-file-size)
+		     (throw 'end-of-file nil))
+		    (t (let ((batch-move (- vlfi-end-pos batch-step)))
+			 (vlfi-move-to-batch
+			  (if (< batch-move match-end-pos)
+			      match-end-pos
+			    batch-move)))
+		       (goto-char (if (< vlfi-start-pos match-end-pos)
+				      (- match-end-pos vlfi-start-pos)
+				    (point-min)))
+		       (progress-reporter-update search-reporter
+						 vlfi-end-pos)))))
+	  (progress-reporter-done search-reporter))
      (if backward
-          (vlfi-goto-match match-end-pos match-start-pos
-                           count to-find)
-        (vlfi-goto-match match-start-pos match-end-pos
-                         count to-find)))))
+	  (vlfi-goto-match match-end-pos match-start-pos
+			   count to-find)
+	(vlfi-goto-match match-start-pos match-end-pos
+			 count to-find)))))

 (defun vlfi-goto-match (match-pos-start match-pos-end count to-find)
  "Move to chunk surrounding MATCH-POS-START and MATCH-POS-END.
@@ -367,41 +359,41 @@ According to COUNT and left TO-FIND, show if search has been
 successful.  Return nil if nothing found."
  (let ((success (zerop to-find)))
    (or success
-        (vlfi-move-to-batch (- match-pos-start
-                               (/ vlfi-batch-size 2))))
+	(vlfi-move-to-batch (- match-pos-start
+			       (/ vlfi-batch-size 2))))
    (let* ((match-end (- match-pos-end vlfi-start-pos))
-           (overlay (make-overlay (- match-pos-start vlfi-start-pos)
-                                  match-end)))
+	   (overlay (make-overlay (- match-pos-start vlfi-start-pos)
+				  match-end)))
      (overlay-put overlay 'face 'region)
      (or success (goto-char match-end))
      (prog1 (cond (success t)
-                   ((< to-find count)
-                    (message "Moved to the %d match which is last"
-                             (- count to-find))
-                    t)
-                   (t (message "Not found")
-                      nil))
-        (sit-for 0.1)
-        (delete-overlay overlay)))))
+		   ((< to-find count)
+		    (message "Moved to the %d match which is last"
+			     (- count to-find))
+		    t)
+		   (t (message "Not found")
+		      nil))
+	(sit-for 0.1)
+	(delete-overlay overlay)))))

 (defun vlfi-re-search-forward (regexp count)
  "Search forward for REGEXP prefix COUNT number of times.
 Search is performed chunk by chunk in `vlfi-batch-size' memory."
  (interactive (list (read-regexp "Search whole file"
-                                  (if regexp-history
-                                      (car regexp-history))
-                                  'regexp-history)
-                     (or current-prefix-arg 1)))
+				  (if regexp-history
+				      (car regexp-history))
+				  'regexp-history)
+		     (or current-prefix-arg 1)))
  (vlfi-re-search regexp count nil))

 (defun vlfi-re-search-backward (regexp count)
  "Search backward for REGEXP prefix COUNT number of times.
 Search is performed chunk by chunk in `vlfi-batch-size' memory."
  (interactive (list (read-regexp "Search whole file backward"
-                                  (if regexp-history
-                                      (car regexp-history))
-                                  'regexp-history)
-                     (or current-prefix-arg 1)))
+				  (if regexp-history
+				      (car regexp-history))
+				  'regexp-history)
+		     (or current-prefix-arg 1)))
  (vlfi-re-search regexp count t))

 ;;; editing
@@ -418,7 +410,7 @@ Search is performed chunk by chunk in `vlfi-batch-size' memory."
  (setq buffer-read-only nil)
  (buffer-enable-undo)
  (message (substitute-command-keys
-            "Editing: Type \\[vlfi-write] to write chunk \
+	    "Editing: Type \\[vlfi-write] to write chunk \
 or \\[vlfi-discard-edit] to discard changes.")))

 (defun vlfi-write-1 ()
@@ -433,31 +425,35 @@ Reopen last viewed chunk."
 If changing size of chunk, may load the remaining part of file first."
  (interactive)
  (when (and (derived-mode-p 'vlfi-mode)
-             (buffer-modified-p)
-             (or (verify-visited-file-modtime)
-                 (y-or-n-p "File has changed since visited or \
+	     (buffer-modified-p)
+	     (or (verify-visited-file-modtime)
+		 (y-or-n-p "File has changed since visited or \
 saved.  Save anyway? ")))
-    (let ((size-change (- vlfi-buffer-size (buffer-size))))
+    (let ((size-change (- vlfi-end-pos vlfi-start-pos
+			  (length
+			   (encode-coding-region
+			    (point-min) (point-max)
+			    buffer-file-coding-system t)))))
      (if (zerop size-change)
-          (vlfi-write-1)
-        (setq vlfi-file-size (nth 7
-                                  (file-attributes buffer-file-name)))
-        (cond ((= vlfi-file-size vlfi-end-pos)
-               (vlfi-write-1))
-              ((y-or-n-p (concat "Changed size of original chunk.  \
+	  (vlfi-write-1)
+	(setq vlfi-file-size (nth 7
+				  (file-attributes buffer-file-name)))
+	(cond ((= vlfi-file-size vlfi-end-pos)
+	       (vlfi-write-1))
+	      ((y-or-n-p (concat "Changed size of original chunk.  \
 Remaining part of the file ["
-                                 (file-size-human-readable
-                                  (- vlfi-file-size vlfi-end-pos))
-                                 "] has to be loaded.  Continue? "))
-               (let ((pos (point)))
-                 (goto-char (point-max))
-                 (insert-file-contents buffer-file-name nil
-                                       vlfi-end-pos vlfi-file-size)
-                 (when (< 0 size-change) ; pad with empty characters
-                   (goto-char (point-max))
-                   (insert-char 32 size-change))
-                 (vlfi-write-1)
-                 (goto-char pos))))))
+				 (file-size-human-readable
+				  (- vlfi-file-size vlfi-end-pos))
+				 "] has to be loaded.  Continue? "))
+	       (let ((pos (point)))
+		 (goto-char (point-max))
+		 (insert-file-contents buffer-file-name nil
+				       vlfi-end-pos vlfi-file-size)
+		 (when (< 0 size-change) ; pad with empty characters
+		   (goto-char (point-max))
+		   (insert-char 32 size-change))
+		 (vlfi-write-1)
+		 (goto-char pos))))))
    t))

 (defun vlfi-discard-edit ()