(smerge-basic-map): Bind smerge-combine-with-next.

(smerge-auto-leave): Make undo re-enable the mode.
(debug-ignored-errors): Add the user-error of impossible resolution.
(smerge-resolve): Move things around a bit, in preparation for later.
(smerge-diff): Don't fail if the buffer has no associated file.
(ediff-ancestor-buffer, ediff-quit-hook): Quieten byte-compiler.
(smerge-conflict-overlay): New function.
(smerge-match-conflict): Don't add text properties here.
(smerge-find-conflict): Instead, add an overlay here.
Also check for the case where we're inside a conflict already, so as to
obviate the need for font-lock-multiline, which is unbearably slow with
large conflicts and ciomplex font-lock patterns.
(smerge-remove-props): Remove overlay rather than text-properties.
(smerge-mode): Don't set font-lock-multiline.
Remove overlays when turned off.

1 files changed, 84 insertions, 28 deletions

diff --git a/lisp/smerge-mode.el b/lisp/smerge-mode.el
index 6ffbdc50cf..912f328915 100644
--- a/lisp/smerge-mode.el
+++ b/lisp/smerge-mode.el
@@ -53,7 +53,7 @@
 (defvar smerge-mode)
 
 (defgroup smerge ()
-  "Minor mode to resolve diff3 conflicts."
+  "Minor mode to highlight and resolve diff3 conflicts."
   :group 'tools
   :prefix "smerge-")
 
@@ -69,13 +69,13 @@
 (defcustom smerge-diff-switches
   (append '("-d" "-b")
 	  (if (listp diff-switches) diff-switches (list diff-switches)))
-  "*A list of strings specifying switches to be passed to diff.
+  "A list of strings specifying switches to be passed to diff.
 Used in `smerge-diff-base-mine' and related functions."
   :group 'smerge
   :type '(repeat string))
 
 (defcustom smerge-auto-leave t
-  "*Non-nil means to leave `smerge-mode' when the last conflict is resolved."
+  "Non-nil means to leave `smerge-mode' when the last conflict is resolved."
   :group 'smerge
   :type 'boolean)
 
@@ -138,6 +138,7 @@ Used in `smerge-diff-base-mine' and related functions."
     ("o" . smerge-keep-other)
     ("m" . smerge-keep-mine)
     ("E" . smerge-ediff)
+    ("C" . smerge-combine-with-next)
     ("\C-m" . smerge-keep-current)
     ("=" . ,(make-sparse-keymap "Diff"))
     ("=<" "base-mine" . smerge-diff-base-mine)
@@ -257,6 +258,8 @@ Can be nil if the style is undecided, or else:
   (when (and smerge-auto-leave
 	     (save-excursion (goto-char (point-min))
 			     (not (re-search-forward smerge-begin-re nil t))))
+    (when (and (listp buffer-undo-list) smerge-mode)
+      (push (list 'apply 'smerge-mode 1) buffer-undo-list))
     (smerge-mode -1)))
 
 
@@ -316,6 +319,7 @@ Can be nil if the style is undecided, or else:
   "Mode-specific merge function.
 The function is called with no argument and with the match data set
 according to `smerge-match-conflict'.")
+(add-to-list 'debug-ignored-errors "Don't know how to resolve")
 
 (defvar smerge-text-properties
   `(help-echo "merge conflict: mouse-3 shows a menu"
@@ -323,10 +327,7 @@ according to `smerge-match-conflict'.")
     keymap (keymap (down-mouse-3 . smerge-popup-context-menu))))
 
 (defun smerge-remove-props (&optional beg end)
-  (remove-text-properties
-   (or beg (match-beginning 0))
-   (or end (match-end 0))
-   smerge-text-properties))
+  (remove-overlays beg end 'smerge 'conflict))
 
 (defun smerge-popup-context-menu (event)
   "Pop up the Smerge mode context menu under mouse."
@@ -368,8 +369,16 @@ some major modes.  Uses `smerge-resolve-function' to do the actual work."
    ;; Trivial diff3 -A non-conflicts.
    ((and (eq (match-end 1) (match-end 3))
 	 (eq (match-beginning 1) (match-beginning 3)))
-    ;; FIXME: Add "if [ diff -b MINE OTHER ]; then select OTHER; fi"
     (smerge-keep-n 3))
+   ;; Mode-specific conflict resolution.
+   ((condition-case nil
+        (atomic-change-group
+         (funcall smerge-resolve-function)
+         t)
+      (error nil))
+    ;; Nothing to do: the resolution function has done it already.
+    nil)
+   ;; FIXME: Add "if [ diff -b MINE OTHER ]; then select OTHER; fi"
    ((and (match-end 2)
 	 ;; FIXME: Add "diff -b BASE MINE | patch OTHER".
 	 ;; FIXME: Add "diff -b BASE OTHER | patch MINE".
@@ -380,8 +389,7 @@ some major modes.  Uses `smerge-resolve-function' to do the actual work."
 	 nil)
     )
    (t
-    ;; Mode-specific conflict resolution.
-    (funcall smerge-resolve-function)))
+    (error "Don't know how to resolve")))
   (smerge-auto-leave))
 
 (defun smerge-keep-base ()
@@ -500,6 +508,10 @@ An error is raised if not inside a conflict."
 	      (re-search-forward smerge-begin-re end t))
 	    ;; There's a nested conflict and we're after the the beginning
 	    ;; of the outer one but before the beginning of the inner one.
+	    ;; Of course, maybe this is not a nested conflict but in that
+	    ;; case it can only be something nastier that we don't know how
+	    ;; to handle, so may as well arbitrarily decide to treat it as
+	    ;; a nested conflict.  --Stef
 	    (error "There is a nested conflict"))
 
 	   ((re-search-backward smerge-base-re start t)
@@ -524,13 +536,6 @@ An error is raised if not inside a conflict."
 	    (setq mine-start other-start)
 	    (setq mine-end   other-end)))
 
-	  (let ((inhibit-read-only t)
-		(inhibit-modification-hooks t)
-		(m (buffer-modified-p)))
-	    (unwind-protect
-		(add-text-properties start end smerge-text-properties)
-	      (restore-buffer-modified-p m)))
-
 	  (store-match-data (list start end
 				  mine-start mine-end
 				  base-start base-end
@@ -540,17 +545,60 @@ An error is raised if not inside a conflict."
 	  t)
       (search-failed (error "Point not in conflict region")))))
 
+(defun smerge-conflict-overlay (pos)
+  "Return the conflict overlay at POS if any."
+  (let ((ols (overlays-at pos))
+        conflict)
+    (dolist (ol ols)
+      (if (and (eq (overlay-get ol 'smerge) 'conflict)
+               (> (overlay-end ol) pos))
+          (setq conflict ol)))
+    conflict))
+
 (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)
-    (condition-case err
-	(progn
-	  (smerge-match-conflict)
-	  (goto-char (match-end 0)))
-      (error (smerge-find-conflict limit)))))
+Returns non-nil if a match is found between point and LIMIT.
+Point is moved to the end of the conflict."
+  (let ((found nil)
+        (pos (point))
+        conflict)
+    ;; First check to see if point is already inside a conflict, using
+    ;; the conflict overlays.
+    (while (and (not found) (setq conflict (smerge-conflict-overlay pos)))
+      ;; Check the overlay's validity and kill it if it's out of date.
+      (condition-case nil
+          (progn
+            (goto-char (overlay-start conflict))
+            (smerge-match-conflict)
+            (goto-char (match-end 0))
+            (if (<= (point) pos)
+                (error "Matching backward!")
+              (setq found t)))
+        (error (smerge-remove-props
+                (overlay-start conflict) (overlay-end conflict))
+               (goto-char pos))))
+    ;; If we're not already inside a conflict, look for the next conflict
+    ;; and add/update its overlay.
+    (while (and (not found) (re-search-forward smerge-begin-re limit t))
+      (condition-case nil
+          (progn
+            (smerge-match-conflict)
+            (goto-char (match-end 0))
+            (let ((conflict (smerge-conflict-overlay (1- (point)))))
+              (if conflict
+                  ;; Update its location, just in case it got messed up.
+                  (move-overlay conflict (match-beginning 0) (match-end 0))
+                (setq conflict (make-overlay (match-beginning 0) (match-end 0)
+                                             nil 'front-advance nil))
+                (overlay-put conflict 'evaporate t)
+                (overlay-put conflict 'smerge 'conflict)
+                (let ((props smerge-text-properties))
+                  (while props
+                    (overlay-put conflict (pop props) (pop props))))))
+            (setq found t))
+        (error nil)))
+    found))
 
 (defun smerge-diff (n1 n2)
   (smerge-match-conflict)
@@ -566,7 +614,12 @@ The point is moved to the end of the conflict."
 	(file1 (make-temp-file "smerge1"))
 	(file2 (make-temp-file "smerge2"))
 	(dir default-directory)
-	(file (file-relative-name buffer-file-name))
+	(file (if buffer-file-name (file-relative-name buffer-file-name)))
+        ;; We would want to use `emacs-mule-unix' for read&write, but we
+        ;; bump into problems with the coding-system used by diff to write
+        ;; the file names and the time stamps in the header.
+        ;; `buffer-file-coding-system' is not always correct either, but if
+        ;; the OS/user uses only one coding-system, then it works.
 	(coding-system-for-read buffer-file-coding-system))
     (write-region beg1 end1 file1 nil 'nomessage)
     (write-region beg2 end2 file2 nil 'nomessage)
@@ -594,6 +647,8 @@ The point is moved to the end of the conflict."
 (defvar ediff-buffer-A)
 (defvar ediff-buffer-B)
 (defvar ediff-buffer-C)
+(defvar ediff-ancestor-buffer)
+(defvar ediff-quit-hook)
 
 ;;;###autoload
 (defun smerge-ediff (&optional name-mine name-other name-base)
@@ -687,7 +742,6 @@ buffer names."
 \\{smerge-mode-map}"
   :group 'smerge :lighter " SMerge"
   (when (and (boundp 'font-lock-mode) font-lock-mode)
-    (set (make-local-variable 'font-lock-multiline) t)
     (save-excursion
       (if smerge-mode
 	  (font-lock-add-keywords nil smerge-font-lock-keywords 'append)
@@ -695,7 +749,9 @@ buffer names."
       (goto-char (point-min))
       (while (smerge-find-conflict)
 	(save-excursion
-	  (font-lock-fontify-region (match-beginning 0) (match-end 0) nil))))))
+	  (font-lock-fontify-region (match-beginning 0) (match-end 0) nil)))))
+  (unless smerge-mode
+    (smerge-remove-props (point-min) (point-max))))
 
 
 (provide 'smerge-mode)