Remove clear-headers from VC's public method set.

* vc/vc.el and all backends: API simplification; clear-headers is no
longer a public method.  It is now local to the one place it's used,
in the RCS steal-lock method.

6 files changed, 23 insertions, 36 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 6c2b33ea566..d005cbef920 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2014-12-02  Eric S. Raymond  <esr@snark.thyrsus.com>
+
+        * vc/vc.el and all backends: API simplification; clear-headers
+        is no longer a public method.  It is now local to the one place
+        it's used, in the RCS steal-lock method.
+
 2014-12-01  Eric S. Raymond  <esr@snark.thyrsus.com>
 
         * vc/vc.el and all backends: API simplification; could-register
diff --git a/lisp/vc/vc-git.el b/lisp/vc/vc-git.el
index 93c5ff805f6..3538f2c3828 100644
--- a/lisp/vc/vc-git.el
+++ b/lisp/vc/vc-git.el
@@ -95,7 +95,6 @@
 ;; - previous-revision (file rev)                  OK
 ;; - next-revision (file rev)                      OK
 ;; - check-headers ()                              COULD BE SUPPORTED
-;; - clear-headers ()                              NOT NEEDED
 ;; - delete-file (file)                            OK
 ;; - rename-file (old new)                         OK
 ;; - find-file-hook ()                             OK
diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index b5be8d5f04c..35f5354da65 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -85,7 +85,6 @@
 ;; - previous-revision (file rev)              OK
 ;; - next-revision (file rev)                  OK
 ;; - check-headers ()                          ??
-;; - clear-headers ()                          ??
 ;; - delete-file (file)                        TEST IT
 ;; - rename-file (old new)                     OK
 ;; - find-file-hook ()                         added for bug#10709
diff --git a/lisp/vc/vc-rcs.el b/lisp/vc/vc-rcs.el
index c9e4d409924..40a102789b9 100644
--- a/lisp/vc/vc-rcs.el
+++ b/lisp/vc/vc-rcs.el
@@ -528,7 +528,22 @@ Needs RCS 5.6.2 or later for -M."
     (vc-do-command "*vc*" 0 "rcs" (vc-master-name file) "-M" (concat "-u" rev))
     ;; Do a real checkout after stealing the lock, so that we see
     ;; expanded headers.
-    (vc-do-command "*vc*" 0 "co" (vc-master-name file) "-f" (concat "-l" rev))))
+    (vc-do-command "*vc*" 0 "co" (vc-master-name file) "-f" (concat "-l" rev))
+    ;; Must clear any headers here because they wouldn't
+    ;; show that the file is locked now.
+    (let* ((filename (or file buffer-file-name))
+           (visited (find-buffer-visiting filename)))
+      (if visited
+          (let ((context (vc-buffer-context)))
+            ;; save-excursion may be able to relocate point and mark
+            ;; properly.  If it fails, vc-restore-buffer-context
+            ;; will give it a second try.
+            (save-excursion
+              (vc-rcs-clear-headers))
+            (vc-restore-buffer-context context))
+        (set-buffer (find-file-noselect filename))
+        (vc-rcs-clear-headers)
+        (kill-buffer filename)))))
 
 (defun vc-rcs-modify-change-comment (files rev comment)
   "Modify the change comments change on FILES on a specified REV.  If FILE is a
@@ -943,7 +958,7 @@ Uses `rcs2log' which only works for RCS and CVS."
 \\(: [\t -#%-\176\240-\377]*\\)?\\$" nil t)))
 
 (defun vc-rcs-clear-headers ()
-  "Implementation of vc-clear-headers for RCS."
+  "Clear RCS header value parts."
   (let ((case-fold-search nil))
     (goto-char (point-min))
     (while (re-search-forward
diff --git a/lisp/vc/vc-src.el b/lisp/vc/vc-src.el
index c93ff96fd29..f3d0585b30c 100644
--- a/lisp/vc/vc-src.el
+++ b/lisp/vc/vc-src.el
@@ -73,7 +73,6 @@
 ;; - previous-revision (file rev)              ??
 ;; - next-revision (file rev)                  ??
 ;; - check-headers ()                          ??
-;; - clear-headers ()                          ??
 ;; - delete-file (file)                        ??
 ;; * rename-file (old new)                     OK
 ;; - find-file-hook ()                         NOT NEEDED
diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 9e6b049e084..52deb13e4dd 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -514,15 +514,6 @@
 ;;
 ;;   Return non-nil if the current buffer contains any version headers.
 ;;
-;; - clear-headers ()
-;;
-;;   In the current buffer, reset all version headers to their unexpanded
-;;   form.  This function should be provided if the state-querying code
-;;   for this backend uses the version headers to determine the state of
-;;   a file.  This function will then be called whenever VC changes the
-;;   version control state in such a way that the headers would give
-;;   wrong information.
-;;
 ;; - delete-file (file)
 ;;
 ;;   Delete FILE and mark it as deleted in the repository.  If this
@@ -1287,9 +1278,6 @@ For old-style locking-based version control systems, like RCS:
                                    "Claim lock retaining changes? ")))
             (progn (vc-call-backend backend 'steal-lock file)
                    (clear-visited-file-modtime)
-                   ;; Must clear any headers here because they wouldn't
-                   ;; show that the file is locked now.
-                   (vc-clear-headers file)
                    (write-file buffer-file-name)
                    (vc-mode-line file backend))
           (if (not (yes-or-no-p
@@ -2001,25 +1989,6 @@ the variable `vc-BACKEND-header'."
               (when (string-match (car f) buffer-file-name)
                 (insert (format (cdr f) (car hdstrings)))))))))))
 
-(defun vc-clear-headers (&optional file)
-  "Clear all version headers in the current buffer (or FILE).
-The headers are reset to their non-expanded form."
-  (let* ((filename (or file buffer-file-name))
-         (visited (find-buffer-visiting filename))
-         (backend (vc-backend filename)))
-    (when (vc-find-backend-function backend 'clear-headers)
-        (if visited
-            (let ((context (vc-buffer-context)))
-              ;; save-excursion may be able to relocate point and mark
-              ;; properly.  If it fails, vc-restore-buffer-context
-              ;; will give it a second try.
-              (save-excursion
-                (vc-call-backend backend 'clear-headers))
-              (vc-restore-buffer-context context))
-          (set-buffer (find-file-noselect filename))
-          (vc-call-backend backend 'clear-headers)
-          (kill-buffer filename)))))
-
 (defun vc-modify-change-comment (files rev oldcomment)
   "Edit the comment associated with the given files and revision."
   ;; Less of a kluge than it looks like; log-view mode only passes