git-blame.el: Use with-current-buffer where appropriate

In git-blame-filter and git-blame-create-overlay we want to save
(along with the values of point and mark) the current-buffer in scope
when calling the functions.  The idiom

    (save-excursion
      (set-buffer buf)
      ...)

will correctly restore the correct buffer, but will not save the
values of point and mark in buf (only in the buffer current when the
save-excursion call is executed).  The intention of these functions is
to save the current buffer from the calling scope and the values of
point and mark in the buffer they are modifying.  The correct idiom
for this is

    (with-current-buffer buf
      (save-excursion
        ...))

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Signed-off-by: Lawrence Mitchell <wence@gmx.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/emacs/git-blame.el

@@ -337,16 +337,16 @@ See also function `git-blame-mode'."
 (defvar in-blame-filter nil)
 
 (defun git-blame-filter (proc str)
-  (save-excursion
-    (set-buffer (process-buffer proc))
-    (goto-char (process-mark proc))
-    (insert-before-markers str)
-    (goto-char 0)
-    (unless in-blame-filter
-      (let ((more t)
-            (in-blame-filter t))
-        (while more
-          (setq more (git-blame-parse)))))))
+  (with-current-buffer (process-buffer proc)
+    (save-excursion
+      (goto-char (process-mark proc))
+      (insert-before-markers str)
+      (goto-char 0)
+      (unless in-blame-filter
+        (let ((more t)
+              (in-blame-filter t))
+          (while more
+            (setq more (git-blame-parse))))))))
 
 (defun git-blame-parse ()
   (cond ((looking-at "\\([0-9a-f]\\{40\\}\\) \\([0-9]+\\) \\([0-9]+\\) \\([0-9]+\\)\n")
@@ -385,33 +385,33 @@ See also function `git-blame-mode'."
           info))))
 
 (defun git-blame-create-overlay (info start-line num-lines)
-  (save-excursion
-    (set-buffer git-blame-file)
-    (let ((inhibit-point-motion-hooks t)
-          (inhibit-modification-hooks t))
-      (goto-char (point-min))
-      (forward-line (1- start-line))
-      (let* ((start (point))
-             (end (progn (forward-line num-lines) (point)))
-             (ovl (make-overlay start end))
-             (hash (car info))
-             (spec `((?h . ,(substring hash 0 6))
-                     (?H . ,hash)
-                     (?a . ,(git-blame-get-info info 'author))
-                     (?A . ,(git-blame-get-info info 'author-mail))
-                     (?c . ,(git-blame-get-info info 'committer))
-                     (?C . ,(git-blame-get-info info 'committer-mail))
-                     (?s . ,(git-blame-get-info info 'summary)))))
-        (push ovl git-blame-overlays)
-        (overlay-put ovl 'git-blame info)
-        (overlay-put ovl 'help-echo
-                     (format-spec git-blame-mouseover-format spec))
-        (if git-blame-use-colors
-            (overlay-put ovl 'face (list :background
-                                         (cdr (assq 'color (cdr info))))))
-        (overlay-put ovl 'line-prefix
-                     (propertize (format-spec git-blame-prefix-format spec)
-                                 'face 'git-blame-prefix-face))))))
+  (with-current-buffer git-blame-file
+    (save-excursion
+      (let ((inhibit-point-motion-hooks t)
+            (inhibit-modification-hooks t))
+        (goto-char (point-min))
+        (forward-line (1- start-line))
+        (let* ((start (point))
+               (end (progn (forward-line num-lines) (point)))
+               (ovl (make-overlay start end))
+               (hash (car info))
+               (spec `((?h . ,(substring hash 0 6))
+                       (?H . ,hash)
+                       (?a . ,(git-blame-get-info info 'author))
+                       (?A . ,(git-blame-get-info info 'author-mail))
+                       (?c . ,(git-blame-get-info info 'committer))
+                       (?C . ,(git-blame-get-info info 'committer-mail))
+                       (?s . ,(git-blame-get-info info 'summary)))))
+          (push ovl git-blame-overlays)
+          (overlay-put ovl 'git-blame info)
+          (overlay-put ovl 'help-echo
+                       (format-spec git-blame-mouseover-format spec))
+          (if git-blame-use-colors
+              (overlay-put ovl 'face (list :background
+                                           (cdr (assq 'color (cdr info))))))
+          (overlay-put ovl 'line-prefix
+                       (propertize (format-spec git-blame-prefix-format spec)
+                                   'face 'git-blame-prefix-face)))))))
 
 (defun git-blame-add-info (info key value)
   (nconc info (list (cons (intern key) value))))