[nongnu] elpa/vc-fossil ec551ba 056/111: Implement previous-revision command for whole repository.

[ELPA Syncer]

branch: elpa/vc-fossil
commit ec551baf01eea39a58a5fe3e290022289cd6f061
Author: fifr <fifr>
Commit: fifr <fifr>

    Implement previous-revision command for whole repository.
    
    If no file is specified, the preceding revision of the current one
    should be returned. This is required for the `log-view-diff-changeset`
    command to work.
---
 vc/el/vc-fossil.el | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/vc/el/vc-fossil.el b/vc/el/vc-fossil.el
index 4aaabd6..24eeeb6 100644
--- a/vc/el/vc-fossil.el
+++ b/vc/el/vc-fossil.el
@@ -328,20 +328,23 @@ If REV is specified, annotate that revision."
 
 (defun vc-fossil-previous-revision (file rev)
   "Fossil specific version of the `vc-previous-revision'."
-  (when file
-    (with-temp-buffer
-      (let ((found (not rev))
-            (newver nil))
-        (insert (vc-fossil--run "finfo" "-l" "-b" (file-truename file)))
-        ;; (vc-fossil--call "fossil" "finfo" "-l" "-b" file)
-        (goto-char (point-min))
-        (while (not (eobp))
-          (let* ((line (buffer-substring-no-properties (point) 
(line-end-position)))
-                 (version (car (split-string line))))
-            (setq newver (or newver (and found version)))
-            (setq found  (string= version rev)))
-          (forward-line))
-        newver))))
+  (if file
+      (with-temp-buffer
+        (let ((found (not rev))
+              (newver nil))
+          (insert (vc-fossil--run "finfo" "-l" "-b" (file-truename file)))
+          ;; (vc-fossil--call "fossil" "finfo" "-l" "-b" file)
+          (goto-char (point-min))
+          (while (not (eobp))
+            (let* ((line (buffer-substring-no-properties (point) 
(line-end-position)))
+                   (version (car (split-string line))))
+              (setq newver (or newver (and found version)))
+              (setq found  (string= version rev)))
+            (forward-line))
+          newver))
+    (let ((info (vc-fossil--run "info" rev)))
+      (and (string-match "parent: *\\([0-9a-fA-F]+\\)" info)
+           (match-string 1 info)))))
 
 (defun vc-fossil-next-revision (file rev)
   "Fossil specific version of the `vc-previous-revision'."