Search only first 10 lines of the buffer to auto-detect diff

kaushalmodi · May 2, 2017 · 252efc1 · 252efc1
1 parent 22fe75f
commit 252efc1
Showing 1 changed file with 24 additions and 19 deletions.
diff --git a/eless b/eless
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Time-stamp: <2017-04-28 15:54:17 kmodi>
+# Time-stamp: <2017-05-02 13:17:58 kmodi>
 #
 # This script uses the unofficial strict mode as explained in
 # http://redsymbol.net/articles/unofficial-bash-strict-mode
@@ -292,24 +292,29 @@ function emacs_Q_view_mode {
                           (defun eless/enable-diff-mode-maybe ()
                             (interactive)
                             (save-excursion
-                              (goto-char (point-min))
-                              (when (re-search-forward "^\\(?:[0-9]+,\\)?[0-9]+\\(?1:[adc]\\)\\(?:[0-9]+,\\)?[0-9]+$" nil :noerror)
-                                (forward-line 1)
-                                (let ((diff-type (match-string-no-properties 1))
-                                      (diff-mode-enable nil))
-                                  (cond
-                                   ;; Line(s) added
-                                   ((string= diff-type "a")
-                                    (when (re-search-forward "^> " nil :noerror)
-                                      (setq diff-mode-enable t)))
-                                   ;; Line(s) deleted or changed
-                                   (t
-                                    (when (re-search-forward "^< " nil :noerror)
-                                      (setq diff-mode-enable t))))
-                                  (when diff-mode-enable
-                                    (diff-mode)
-                                    (rename-buffer "*Diff*" :unique)
-                                    (view-mode 1)))))) ;Re-enable view-mode
+                              (let* ((max-line 10) ;Search first MAX-LINE lines of the buffer
+                                     (bound (progn
+                                              (goto-char (point-min))
+                                              (forward-line max-line)
+                                              (point))))
+                                (goto-char (point-min))
+                                (when (re-search-forward "^\\(?:[0-9]+,\\)?[0-9]+\\(?1:[adc]\\)\\(?:[0-9]+,\\)?[0-9]+$" bound :noerror)
+                                  (forward-line 1)
+                                  (let ((diff-type (match-string-no-properties 1))
+                                        (diff-mode-enable nil))
+                                    (cond
+                                     ;; Line(s) added
+                                     ((string= diff-type "a")
+                                      (when (re-search-forward "^> " nil :noerror)
+                                        (setq diff-mode-enable t)))
+                                     ;; Line(s) deleted or changed
+                                     (t
+                                      (when (re-search-forward "^< " nil :noerror)
+                                        (setq diff-mode-enable t))))
+                                    (when diff-mode-enable
+                                      (diff-mode)
+                                      (rename-buffer "*Diff*" :unique)
+                                      (view-mode 1))))))) ;Re-enable view-mode
 
                           (defun eless/kill-emacs-or-buffer ()
                             (interactive)