[elpa] scratch/add-vdiff 528a5ce 051/258: Simplify logic for sending/receiving changes

[Justin Burkett]

branch: scratch/add-vdiff
commit 528a5cefcf059bb343086910e06edd1790da5ef0
Author: justbur <address@hidden>
Commit: justbur <address@hidden>

    Simplify logic for sending/receiving changes
    
    Store reference to other overlay in each overlay which makes finding the
    other text easy and also ties the text sent and received to what is seen
    on the screen.
---
 vdiff.el | 172 ++++++++++++++++++++++++++++-----------------------------------
 1 file changed, 76 insertions(+), 96 deletions(-)

diff --git a/vdiff.el b/vdiff.el
index 7321731..135436e 100644
--- a/vdiff.el
+++ b/vdiff.el
@@ -336,36 +336,33 @@ text on the first line, and the width of the buffer."
      (concat (mapconcat #'identity string "\n") "\n")
      'face 'vdiff-subtraction-face)))
 
-(defun vdiff--add-subtraction-overlays (buffer start-line target-range amount)
+(defun vdiff--add-subtraction-overlay (buffer start-line amount)
   (with-current-buffer buffer
     (vdiff--move-to-line start-line)
     (let* ((ovr (make-overlay (point) (point))))
       (overlay-put ovr 'before-string 
                    (vdiff--make-subtraction-string amount))
-      (overlay-put ovr 'vdiff-target-range target-range)
       (overlay-put ovr 'vdiff-type 'subtraction)
-      (overlay-put ovr 'vdiff t))))
+      (overlay-put ovr 'vdiff t)
+      ovr)))
 
-(defun vdiff--add-change-overlays
-    (buffer start-line lines target-range
-            &optional addition subtraction-padding)
+(defun vdiff--add-change-overlay
+    (buffer start-line lines &optional addition subtraction-padding)
   (with-current-buffer buffer
     (vdiff--move-to-line start-line)
     (let ((beg (point))
           (end (progn (forward-line lines)
                       (point))))
-      (let ((ovr (make-overlay beg end)))
-        (overlay-put ovr 'face (if addition
-                                   'vdiff-addition-face
-                                 'vdiff-change-face))
-        (overlay-put ovr 'vdiff-type (if addition
-                                         'addition
-                                       'change))
+      (let ((ovr (make-overlay beg end))
+            (type (if addition 'addition 'change))
+            (face (if addition 'vdiff-addition-face 'vdiff-change-face)))
+        (overlay-put ovr 'vdiff-type type)
+        (overlay-put ovr 'face face)
         (overlay-put ovr 'vdiff t)
-        (overlay-put ovr 'vdiff-target-range target-range)
         (when subtraction-padding
           (overlay-put ovr 'after-string
-                       (vdiff--make-subtraction-string 
subtraction-padding)))))))
+                       (vdiff--make-subtraction-string subtraction-padding)))
+        ovr))))
 
 (defun vdiff-fold-string-default (lines first-line width)
   "Produces default format line for closed folds. See
@@ -490,37 +487,38 @@ text on the first line, and the width of the buffer."
           (setq a-last-post-end (1+ a-end))
           (setq b-last-post-end (1+ b-end))
 
-          (cond ((string= code "d")
-                 (vdiff--add-subtraction-overlays
-                  b-buffer b-beg a-norm-range a-length)
-                 (vdiff--add-change-overlays
-                  a-buffer a-beg a-length b-norm-range t))
-
-                ((string= code "a")
-                 (vdiff--add-subtraction-overlays
-                  a-buffer a-beg b-norm-range b-length)
-                 (vdiff--add-change-overlays
-                  b-buffer b-beg b-length a-norm-range t))
-
-                ((and (string= code "c") (> a-length b-length))
-                 (vdiff--add-change-overlays
-                  a-buffer a-beg a-length b-norm-range)
-                 (vdiff--add-change-overlays
-                  b-buffer b-beg b-length a-norm-range
-                  nil (- a-length b-length)))
-
-                ((and (string= code "c") (< a-length b-length))
-                 (vdiff--add-change-overlays
-                  a-buffer a-beg a-length b-norm-range
-                  nil (- b-length a-length))
-                 (vdiff--add-change-overlays
-                  b-buffer b-beg b-length a-norm-range))
-
-                ((string= code "c")
-                 (vdiff--add-change-overlays
-                  a-buffer a-beg a-length b-norm-range)
-                 (vdiff--add-change-overlays
-                  b-buffer b-beg b-length a-norm-range)))))
+          (let (ovr-a ovr-b)
+            (cond ((not (member code (list "a" "d" "c")))
+                   (user-error "vdiff: Problem with diff output parsing"))
+                  ((string= code "d")
+                   (setq ovr-a
+                         (vdiff--add-change-overlay a-buffer a-beg a-length t))
+                   (setq ovr-b
+                         (vdiff--add-subtraction-overlay b-buffer b-beg 
a-length)))
+                  ((string= code "a")
+                   (setq ovr-a
+                         (vdiff--add-subtraction-overlay a-buffer a-beg 
b-length))
+                   (setq ovr-b
+                         (vdiff--add-change-overlay b-buffer b-beg b-length 
t)))
+                  ((> a-length b-length)
+                   (setq ovr-a
+                         (vdiff--add-change-overlay a-buffer a-beg a-length))
+                   (setq ovr-b
+                         (vdiff--add-change-overlay
+                          b-buffer b-beg b-length nil (- a-length b-length))))
+                  ((< a-length b-length)
+                   (setq ovr-a
+                         (vdiff--add-change-overlay
+                          a-buffer a-beg a-length nil (- b-length a-length)))
+                   (setq ovr-b
+                         (vdiff--add-change-overlay b-buffer b-beg b-length)))
+                  (t
+                   (setq ovr-a
+                         (vdiff--add-change-overlay a-buffer a-beg a-length))
+                   (setq ovr-b
+                         (vdiff--add-change-overlay b-buffer b-beg b-length))))
+            (overlay-put ovr-a 'vdiff-other-overlay ovr-b)
+            (overlay-put ovr-b 'vdiff-other-overlay ovr-a))))
       (push (cons (cons a-last-post-end
                         (with-current-buffer a-buffer
                           (line-number-at-pos (point-max))))
@@ -556,11 +554,17 @@ changes under point or on the immediately preceding line."
    (vdiff--region-or-close-overlay))
   (let* ((ovrs (overlays-in beg end)))
     (dolist (ovr ovrs)
-      (cond ((memq (overlay-get ovr 'vdiff-type)
+      (cond ((and (overlay-get ovr 'vdiff-other-overlay)
+                  receive)
+             (let* ((other-ovr (overlay-get ovr 'vdiff-other-overlay))
+                    (pos (overlay-start other-ovr)))
+               (vdiff--with-other-window
+                (vdiff-send-changes pos (1+ pos)))))
+            ((memq (overlay-get ovr 'vdiff-type)
                    '(change addition))
-             (vdiff--transmit-change-overlay ovr receive))
+             (vdiff--transmit-change-overlay ovr))
             ((eq (overlay-get ovr 'vdiff-type) 'subtraction)
-             (vdiff--transmit-subtraction-overlay ovr receive))))
+             (vdiff--transmit-subtraction-overlay ovr))))
     (vdiff-refresh)))
 
 (defun vdiff-receive-changes (beg end)
@@ -571,53 +575,29 @@ changes under point or on the immediately preceding line."
   (interactive (vdiff--region-or-close-overlay))
   (vdiff-send-changes beg end t))
 
-(defun vdiff--transmit-change-overlay (chg-ovr &optional receive)
-  (cond ((not (overlayp chg-ovr))
-         (message "No change found"))
-        (receive
-         (let* ((target-rng (overlay-get chg-ovr 'vdiff-target-range))
-                (pos (vdiff--pos-at-line-beginning
-                      (car target-rng) (vdiff--other-buffer))))
-           (vdiff--with-other-window
-            (vdiff-send-changes pos (1+ pos)))))
-        (t
-         (let* ((addition (eq 'addition (overlay-get chg-ovr 'vdiff-type)))
-                (target-rng (overlay-get chg-ovr 'vdiff-target-range))
-                (text (buffer-substring-no-properties
-                       (overlay-start chg-ovr)
-                       (overlay-end chg-ovr))))
-           (with-current-buffer (vdiff--other-buffer)
-             (if addition
-                 (vdiff--move-to-line (1+ (car target-rng)))
-               (vdiff--move-to-line (car target-rng))
-               (delete-region (point)
-                              (save-excursion
-                                (forward-line
-                                 (1+ (- (cdr target-rng)
-                                        (car target-rng))))
-                                (point))))
-             (insert text))))))
-
-(defun vdiff--transmit-subtraction-overlay (sub-ovr &optional receive)
-  (cond ((not (overlayp sub-ovr))
-         (message "No change found"))
-        (receive
-         (let* ((target-rng (overlay-get sub-ovr 'vdiff-target-range))
-                (pos (vdiff--pos-at-line-beginning
-                      (car target-rng) (vdiff--other-buffer))))
-           (vdiff--with-other-window
-            (vdiff-send-changes pos (1+ pos)))))
-        (t
-         (let* ((target-rng
-                 (overlay-get sub-ovr 'vdiff-target-range)))
-           (when target-rng
-             (with-current-buffer (vdiff--other-buffer)
-               (vdiff--move-to-line (car target-rng))
-               (delete-region (point)
-                              (save-excursion
-                                (vdiff--move-to-line
-                                 (1+ (cdr target-rng)))
-                                (point)))))))))
+(defun vdiff--transmit-change-overlay (ovr)
+  (if (not (overlayp ovr))
+         (message "No change found")
+    (let* ((addition (eq 'addition (overlay-get ovr 'vdiff-type)))
+           (other-ovr (overlay-get ovr 'vdiff-other-overlay))
+           (text (buffer-substring-no-properties
+                  (overlay-start ovr)
+                  (overlay-end ovr))))
+      (with-current-buffer (vdiff--other-buffer)
+        (goto-char (overlay-start other-ovr))
+        (unless addition
+          (delete-region (overlay-start other-ovr)
+                         (overlay-end other-ovr)))
+        (insert text)))))
+
+(defun vdiff--transmit-subtraction-overlay (ovr)
+  (if (not (overlayp ovr))
+         (message "No change found")
+    (let* ((other-ovr (overlay-get ovr 'vdiff-other-overlay)))
+      (when other-ovr
+        (with-current-buffer (vdiff--other-buffer)
+          (delete-region (overlay-start other-ovr)
+                         (overlay-end other-ovr)))))))
 
 ;; * Scrolling and line syncing