From 3dac25a97282fd026de4abe51496f752da1929fd Mon Sep 17 00:00:00 2001
From: Stefan Monnier <monnier@iro.umontreal.ca>
Date: Thu, 9 Dec 1999 13:03:41 +0000
Subject: [PATCH] New file.  Provides a simple minor-mode for files containing
 diff3-style conflict markers, such as generated by RCS

---
 lisp/ChangeLog      |  13 +-
 lisp/smerge-mode.el | 453 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 465 insertions(+), 1 deletion(-)
 create mode 100644 lisp/smerge-mode.el

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 57621963a78..228aac9e29c 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,15 @@
+1999-12-09  Stefan Monnier  <monnier@cs.yale.edu>
+
+	* smerge-mode.el: New file.
+
+	* font-lock.el (font-lock-multiline): New variable.
+	(font-lock-add-keywords): Rename `major-mode' into `mode'.
+	(font-lock-remove-keywords): Added a dummy `mode' argument for
+	potential future support.
+	(font-lock-fontify-anchored-keywords, 
+	(font-lock-fontify-keywords-region): Only handle multiline strings
+	if necessary (avoids a pathological behavior in (f.ex) diff-mode).
+
 1999-12-08  Richard M. Stallman  <rms@caffeine.ai.mit.edu>
 
 	* bookmark.el (bookmark-bmenu-mode-map): Bind RET like f.
@@ -237,7 +249,6 @@
 
 	* delsel.el: Grok skeleton-pair-insert-maybe.
 
->>>>>>> 1.224
 1999-11-30  Richard M. Stallman  <rms@caffeine.ai.mit.edu>
 
 	* progmodes/cperl-mode.el (cperl-under-as-char):
diff --git a/lisp/smerge-mode.el b/lisp/smerge-mode.el
new file mode 100644
index 00000000000..14b0a3acaca
--- /dev/null
+++ b/lisp/smerge-mode.el
@@ -0,0 +1,453 @@
+;;; smerge-mode.el --- Minor mode to resolve diff3 conflicts
+
+;; Copyright (C) 1999  Free Software Foundation, Inc.
+
+;; Author: Stefan Monnier <monnier@cs.yale.edu>
+;; Keywords: merge diff3 cvs conflict
+;; Revision: $Id$
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Commentary:
+
+;; Provides a lightweight alternative to emerge/ediff.
+;; To use it, simply add to your .emacs the following lines:
+;;
+;;   (autoload 'smerge-mode "smerge-mode" nil t)
+;;
+;; you can even have it turned on automatically with the following
+;; piece of code in your .emacs:
+;;
+;;   (defun sm-try-smerge ()
+;;     (save-excursion
+;;   	 (goto-char (point-min))
+;;   	 (when (re-search-forward "^<<<<<<< " nil t)
+;;   	   (smerge-mode 1))))
+;;   (add-hook 'find-file-hooks 'sm-try-smerge t)
+
+;;; Code:
+
+(eval-when-compile (require 'cl))
+
+
+(defgroup smerge ()
+  "Minor mode to resolve diff3 conflicts."
+  :group 'tools
+  :prefix "smerge-")
+
+(defcustom smerge-diff-buffer-name "*smerge-diff*"
+  "Buffer name to use for displaying diffs."
+  :group 'smerge
+  :type '(choice
+	  (const "*vc-diff*")
+	  (const "*cvs-diff*")
+	  (const "*smerge-diff*")
+	  string))
+
+(defcustom smerge-diff-switches
+  (list* "-d" "-b"
+	 (if (listp diff-switches) diff-switches (list diff-switches)))
+  "*A list of strings specifying switches to be be passed to diff.
+Used in `smerge-diff-base-mine' and related functions."
+  :group 'smerge
+  :type '(repeat string))
+
+(defface smerge-mine-face
+  '((t (:foreground "blue")))
+  "Face for your code."
+  :group 'smerge)
+(defvar smerge-mine-face 'smerge-mine-face)
+
+(defface smerge-other-face
+  '((t (:foreground "darkgreen")))
+  "Face for the other code."
+  :group 'smerge)
+(defvar smerge-other-face 'smerge-other-face)
+
+(defface smerge-base-face
+  '((t (:foreground "red")))
+  "Face for the base code."
+  :group 'smerge)
+(defvar smerge-base-face 'smerge-base-face)
+
+(defface smerge-markers-face
+  '((t (:background "grey85")))
+  "Face for the conflict markers."
+  :group 'smerge)
+(defvar smerge-markers-face 'smerge-markers-face)
+
+(defmacro smerge-defmap (var bindings &optional doc)
+  `(defvar ,var
+     (let ((m (make-sparse-keymap)))
+       (dolist (b ,bindings)
+	 (if (equal (car b) "")
+	     (set-keymap-parent m (cdr b))
+	   (define-key m (car b) (cdr b))))
+       m)
+     ,doc))
+
+(smerge-defmap smerge-basic-keymap
+  '(("n" . smerge-next)
+    ("p" . smerge-prev)
+    ("a" . smerge-keep-all)
+    ("b" . smerge-keep-base)
+    ("o" . smerge-keep-other)
+    ("m" . smerge-keep-mine)
+    ("E" . smerge-ediff)
+    ("\C-m" . smerge-keep-current)
+    ("<" . smerge-diff-base-mine)
+    (">" . smerge-diff-base-other)
+    ("=" . smerge-diff-mine-other))
+  "The base keymap for `smerge-mode'.")
+(fset 'smerge-basic-keymap smerge-basic-keymap)
+
+(defcustom smerge-command-prefix "\e"
+  "Prefix for `smerge-mode' commands."
+  :group 'smerge
+  :type '(choice (string "\e") (string "C-x^") (string "") string))
+
+(smerge-defmap smerge-mode-map
+  `((,smerge-command-prefix . smerge-basic-keymap))
+  "Keymap for `smerge-mode'.")
+
+(easy-menu-define smerge-mode-menu smerge-mode-map
+  "Menu for `smerge-mode'."
+  '("SMerge"
+    ["Invoke Ediff"		smerge-ediff		t]
+    ))
+
+(defconst smerge-font-lock-keywords
+  '((smerge-find-conflict
+     (1 smerge-mine-face prepend)
+     (2 smerge-base-face prepend t)
+     (3 smerge-other-face prepend t)
+     (0 smerge-markers-face keep)
+     (4 nil t t)
+     (5 nil t t)))
+  "Font lock patterns for `smerge-mode'.")
+
+(defconst smerge-begin-re "^<<<<<<< \\(.*\\)\n")
+(defconst smerge-end-re "^>>>>>>> .*\n")
+(defconst smerge-base-re "^||||||| .*\n")
+(defconst smerge-other-re "^=======\n")
+
+(defvar smerge-conflict-style nil
+  "Keep track of which style of conflict is in use.
+Can be nil if the style is undecided, or else:
+- `diff3-E'
+- `diff3-A'")
+
+;; Compiler pacifiers
+(defvar font-lock-mode nil)
+(defvar font-lock-keywords nil)
+(eval-when-compile
+  (unless (fboundp 'font-lock-fontify-region)
+    (autoload 'font-lock-fontify-region "font-lock")))
+
+;;;;
+;;;; Actual code
+;;;;
+
+(defun smerge-next (&optional count)
+  "Go to the next COUNT'th conflict."
+  (interactive)
+  (unless count (setq count 1))
+  (if (< count 0) (smerge-prev (- count))
+    (if (looking-at smerge-begin-re) (incf count))
+    (unless (re-search-forward smerge-begin-re nil t count)
+      (error "No next conflict"))
+    (goto-char (match-beginning 0))))
+
+(defun smerge-prev (&optional count)
+  "Go to the previous COUNT'th conflict."
+  (interactive)
+  (unless count (setq count 1))
+  (if (< count 0) (smerge-next (- count))
+    (unless (re-search-backward smerge-begin-re nil t count)
+      (error "No previous conflict"))))
+
+(defconst smerge-match-names ["conflict" "mine" "base" "other"])
+
+(defun smerge-ensure-match (n)
+  (unless (match-end n)
+    (error (format "No `%s'" (aref smerge-match-names n)))))
+
+(defun smerge-keep-all ()
+  "Keep all three versions.
+Convenient for the kind of conflicts that can arise in ChangeLog files."
+  (interactive)
+  (smerge-match-conflict)
+  (replace-match (concat (or (match-string 1) "")
+			 (or (match-string 2) "")
+			 (or (match-string 3) ""))
+		 t t))
+
+(defun smerge-keep-base ()
+  "Revert to the base version."
+  (interactive)
+  (smerge-match-conflict)
+  (smerge-ensure-match 2)
+  (replace-match (match-string 2) t t))
+
+(defun smerge-keep-other ()
+  "Use \"other\" version."
+  (interactive)
+  (smerge-match-conflict)
+  ;;(smerge-ensure-match 3)
+  (replace-match (match-string 3) t t))
+
+(defun smerge-keep-mine ()
+  "Keep your version."
+  (interactive)
+  (smerge-match-conflict)
+  ;;(smerge-ensure-match 1)
+  (replace-match (match-string 1) t t))
+
+(defun smerge-keep-current ()
+  "Use the current (under the cursor) version."
+  (interactive)
+  (smerge-match-conflict)
+  (let ((i 3))
+    (while (or (not (match-end i))
+	       (< (point) (match-beginning i))
+	       (>= (point) (match-end i)))
+      (decf i))
+    (if (<= i 0) (error "Not inside a version")
+      (replace-match (match-string i) t t))))
+
+(defun smerge-diff-base-mine ()
+  "Diff 'base' and 'mine' version in current conflict region."
+  (interactive)
+  (smerge-diff 2 1))
+
+(defun smerge-diff-base-other ()
+  "Diff 'base' and 'other' version in current conflict region."
+  (interactive)
+  (smerge-diff 2 3))
+
+(defun smerge-diff-mine-other ()
+  "Diff 'mine' and 'other' version in current conflict region."
+  (interactive)
+  (smerge-diff 1 3))
+
+(defun smerge-match-conflict ()
+  "Get info about the conflict.  Puts the info in the `match-data'.
+The submatches contain:
+ 0:  the whole conflict.
+ 1:  your code.
+ 2:  the base code.
+ 3:  other code.
+An error is raised if not inside a conflict."
+  (save-excursion
+    (condition-case nil
+	(let* ((orig-point (point))
+
+	       (_ (forward-line 1))
+	       (_ (re-search-backward smerge-begin-re))
+
+	       (start (match-beginning 0))
+	       (mine-start (match-end 0))
+	       (filename (match-string 1))
+
+	       (_ (re-search-forward smerge-end-re))
+	       (_ (assert (< orig-point (match-end 0))))
+	       
+	       (other-end (match-beginning 0))
+	       (end (match-end 0))
+
+	       (_ (re-search-backward smerge-other-re start))
+
+	       (mine-end (match-beginning 0))
+	       (other-start (match-end 0))
+
+	       base-start base-end)
+
+	  ;; handle the various conflict styles
+	  (cond
+	   ((re-search-backward smerge-base-re start t)
+	    ;; a 3-parts conflict
+	    (set (make-local-variable 'smerge-conflict-style) 'diff3-A)
+	    (setq base-end mine-end)
+	    (setq mine-end (match-beginning 0))
+	    (setq base-start (match-end 0)))
+
+	  ((string= filename (file-name-nondirectory
+			      (or buffer-file-name "")))
+	   ;; a 2-parts conflict
+	   (set (make-local-variable 'smerge-conflict-style) 'diff3-E))
+
+	  ((and (not base-start)
+		(or (eq smerge-conflict-style 'diff3-A)
+		    (string-match "^[.0-9]+\\'" filename)))
+	   ;; a same-diff conflict
+	   (setq base-start mine-start)
+	   (setq base-end   mine-end)
+	   (setq mine-start other-start)
+	   (setq mine-end   other-end)))
+	       
+	  (store-match-data (list start end
+				  mine-start mine-end
+				  base-start base-end
+				  other-start other-end
+				  (when base-start (1- base-start)) base-start
+				  (1- other-start) other-start))
+	  t)
+      (error "Point not in conflict region"))))
+
+(defun smerge-find-conflict (&optional limit)
+  "Find and match a conflict region.  Intended as a font-lock MATCHER.
+The submatches are the same as in `smerge-match-conflict'.
+Returns non-nil if a match is found between the point and LIMIT.
+The point is moved to the end of the conflict."
+  (when (re-search-forward smerge-begin-re limit t)
+    (ignore-errors
+      (smerge-match-conflict)
+      (goto-char (match-end 0)))))
+
+(defun smerge-diff (n1 n2)
+  (smerge-match-conflict)
+  (smerge-ensure-match n1)
+  (smerge-ensure-match n2)
+  (let ((name1 (aref smerge-match-names n1))
+	(name2 (aref smerge-match-names n2))
+	(file1 (make-temp-file "smerge1"))
+	(file2 (make-temp-file "smerge2")))
+    (write-region (match-beginning n1) (match-end n1) file1)
+    (write-region (match-beginning n2) (match-end n2) file2)
+    (unwind-protect
+	(with-current-buffer (get-buffer-create smerge-diff-buffer-name)
+	  (let ((inhibit-read-only t))
+	    (erase-buffer)
+	    (apply 'call-process diff-command nil t nil
+		   (append smerge-diff-switches
+			   (list "-L" name1 "-L" name2 file1 file2))))
+	  (goto-char (point-min))
+	  (diff-mode)
+	  (display-buffer (current-buffer) t))
+      (delete-file file1)
+      (delete-file file2))))
+
+(eval-when-compile
+  ;; compiler pacifiers
+  (defvar smerge-ediff-windows)
+  (defvar smerge-ediff-buf)
+  (defvar ediff-buffer-A)
+  (defvar ediff-buffer-B)
+  (defvar ediff-buffer-C)
+  (unless (fboundp 'ediff-cleanup-mess)
+    (autoload 'ediff-cleanup-mess "ediff-util")))
+
+(defun smerge-ediff ()
+  "Invoke ediff to resolve the conflicts."
+  (interactive)
+  (let* ((buf (current-buffer))
+	 (mode major-mode)
+	 ;;(ediff-default-variant 'default-B)
+	 (config (current-window-configuration))
+	 (filename (file-name-nondirectory buffer-file-name))
+	 (mine (generate-new-buffer (concat "*" filename " MINE*")))
+	 (other (generate-new-buffer (concat "*" filename " OTHER*")))
+	 base)
+    (with-current-buffer mine
+      (buffer-disable-undo)
+      (insert-buffer-substring buf)
+      (goto-char (point-min))
+      (while (smerge-find-conflict)
+	(when (match-beginning 2) (setq base t))
+	(replace-match (match-string 1) t t))
+      (buffer-enable-undo)
+      (set-buffer-modified-p nil)
+      (funcall mode))
+
+    (with-current-buffer other
+      (buffer-disable-undo)
+      (insert-buffer-substring buf)
+      (goto-char (point-min))
+      (while (smerge-find-conflict)
+	(replace-match (match-string 3) t t))
+      (buffer-enable-undo)
+      (set-buffer-modified-p nil)
+      (funcall mode))
+    
+    (when base
+      (setq base (generate-new-buffer (concat "*" filename " BASE*")))
+      (with-current-buffer base
+	(buffer-disable-undo)
+	(insert-buffer-substring buf)
+	(goto-char (point-min))
+	(while (smerge-find-conflict)
+	  (replace-match (or (match-string 2) "") t t))
+	(buffer-enable-undo)
+	(set-buffer-modified-p nil)
+	(funcall mode)))
+    
+    ;; the rest of the code is inspired from vc.el
+    ;; Fire up ediff.
+    (set-buffer
+     (if base
+	 (ediff-merge-buffers-with-ancestor mine other base)
+	  ;; nil 'ediff-merge-revisions-with-ancestor buffer-file-name)
+       (ediff-merge-buffers mine other)))
+        ;; nil 'ediff-merge-revisions buffer-file-name)))
+    
+    ;; Ediff is now set up, and we are in the control buffer.
+    ;; Do a few further adjustments and take precautions for exit.
+    (set (make-local-variable 'smerge-ediff-windows) config)
+    (set (make-local-variable 'smerge-ediff-buf) buf)
+    (set (make-local-variable 'ediff-quit-hook)
+	 (lambda ()
+	   (let ((buffer-A ediff-buffer-A)
+		 (buffer-B ediff-buffer-B)
+		 (buffer-C ediff-buffer-C)
+		 (buffer-Ancestor ediff-ancestor-buffer)
+		 (buf smerge-ediff-buf)
+		 (windows smerge-ediff-windows))
+	     (ediff-cleanup-mess)
+	     (with-current-buffer buf
+	       (erase-buffer)
+	       (insert-buffer buffer-C)
+	       (kill-buffer buffer-A)
+	       (kill-buffer buffer-B)
+	       (kill-buffer buffer-C)
+	       (when (bufferp buffer-Ancestor) (kill-buffer buffer-Ancestor))
+	       (set-window-configuration windows)
+	       (message "Conflict resolution finished; you may save the buffer")))))
+    (message "Please resolve conflicts now; exit ediff when done")))
+
+
+;;;###autoload
+(define-minor-mode smerge-mode
+  "Minor mode to simplify editing output from the diff3 program.
+\\{smerge-mode-map}"
+  nil " SMerge" nil
+  (when font-lock-mode
+    (save-excursion
+      (if smerge-mode
+	  (font-lock-add-keywords nil smerge-font-lock-keywords 'append)
+	(font-lock-remove-keywords nil smerge-font-lock-keywords))
+      (goto-char (point-min))
+      (while (smerge-find-conflict)
+	(font-lock-fontify-region (match-beginning 0) (match-end 0) nil)))))
+
+
+(provide 'smerge-mode)
+
+;;; Change Log:
+;; $Log$
+
+;;; smerge-mode.el ends here