[Emacs-diffs] Changes to emacs/lisp/files.el,v

[Miles Bader]

CVSROOT:        /cvsroot/emacs
Module name:    emacs
Changes by:     Miles Bader <miles>     07/05/11 04:44:30

Index: lisp/files.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/files.el,v
retrieving revision 1.896
retrieving revision 1.897
diff -u -b -r1.896 -r1.897
--- lisp/files.el       23 Apr 2007 07:17:08 -0000      1.896
+++ lisp/files.el       11 May 2007 04:44:29 -0000      1.897
@@ -2151,8 +2151,21 @@
 \"allow `auto-mode-alist' to decide for these files.\")")
 (put 'magic-mode-alist 'risky-local-variable t)
 
+(defvar file-start-mode-alist
+  nil
+  "Like `magic-mode-alist' but has lower priority than `auto-mode-alist'.
+Each element looks like (REGEXP . FUNCTION) or (MATCH-FUNCTION . FUNCTION).
+After visiting a file, if REGEXP matches the text at the beginning of the
+buffer, or calling MATCH-FUNCTION returns non-nil, `normal-mode' will
+call FUNCTION, provided that `magic-mode-alist' and `auto-mode-alist'
+have not specified a mode for this file.
+
+If FUNCTION is nil, then it is not called.")
+(put 'file-start-mode-alist 'risky-local-variable t)
+
 (defvar magic-mode-regexp-match-limit 4000
-  "Upper limit on `magic-mode-alist' regexp matches.")
+  "Upper limit on `magic-mode-alist' regexp matches.
+Also applies to `file-start-mode-alist'.")
 
 (defun set-auto-mode (&optional keep-mode-if-same)
   "Select major mode appropriate for current buffer.
@@ -2207,10 +2220,10 @@
              (or (set-auto-mode-0 mode keep-mode-if-same)
                  ;; continuing would call minor modes again, toggling them off
                  (throw 'nop nil))))))
-    (unless done
       ;; If we didn't, look for an interpreter specified in the first line.
       ;; As a special case, allow for things like "#!/bin/env perl", which
       ;; finds the interpreter anywhere in $PATH.
+    (unless done
       (setq mode (save-excursion
                   (goto-char (point-min))
                   (if (looking-at auto-mode-interpreter-regexp)
@@ -2223,7 +2236,7 @@
       ;; If we found an interpreter mode to use, invoke it now.
       (if done
          (set-auto-mode-0 (cdr done) keep-mode-if-same)))
-    ;; If we didn't, match the buffer beginning against magic-mode-alist.
+    ;; Next try matching the buffer beginning against magic-mode-alist.
     (unless done
       (if (setq done (save-excursion
                       (goto-char (point-min))
@@ -2236,8 +2249,9 @@
                                          (if (functionp re)
                                              (funcall re)
                                            (looking-at re)))))))
-         (set-auto-mode-0 done keep-mode-if-same)
-       ;; Compare the filename against the entries in auto-mode-alist.
+         (set-auto-mode-0 done keep-mode-if-same)))
+    ;; Next compare the filename against the entries in auto-mode-alist.
+    (unless done
        (if buffer-file-name
            (let ((name buffer-file-name))
              ;; Remove backup-suffixes from file name.
@@ -2268,7 +2282,22 @@
                          name (substring name 0 (match-beginning 0)))
                  (setq name))
                (when mode
-                 (set-auto-mode-0 mode keep-mode-if-same)))))))))
+               (set-auto-mode-0 mode keep-mode-if-same)
+               (setq done t))))))
+    ;; Next try matching the buffer beginning against file-start-mode-alist.
+    (unless done
+      (if (setq done (save-excursion
+                      (goto-char (point-min))
+                      (save-restriction
+                        (narrow-to-region (point-min)
+                                          (min (point-max)
+                                               (+ (point-min) 
magic-mode-regexp-match-limit)))
+                        (assoc-default nil file-start-mode-alist
+                                       (lambda (re dummy)
+                                         (if (functionp re)
+                                             (funcall re)
+                                           (looking-at re)))))))
+         (set-auto-mode-0 done keep-mode-if-same)))))
 
 ;; When `keep-mode-if-same' is set, we are working on behalf of
 ;; set-visited-file-name.  In that case, if the major mode specified is the