Improve performance of `find-buffer-visiting' (bug#66117)

* src/buffer.c (Fget_truename_buffer): Expose `get_truename_buffer' to
Elisp.
(Ffind_buffer): New subr searching for a live buffer with a given
value of buffer-local variable.
(syms_of_buffer): Register the new added subroutines.
* src/filelock.c (lock_file): Use the new `Fget_truename_buffer' name.
* src/lisp.h:
* test/manual/etags/c-src/emacs/src/lisp.h: Remove no-longer-necessary
extern declarations for `get_truename_buffer'.
* lisp/files.el (find-buffer-visiting): Refactor, using subroutines to
search for buffers instead of slow manual Elisp iterations.

diff --git a/lisp/files.el b/lisp/files.el
index caa0622ab0828d0e7f758b690d51c291c5f8e826..315ba831e8cd03db80e9d7fc1456a79105bced9b 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -2208,37 +2208,29 @@ and others are ignored.  PREDICATE is called with the buffer as
 the only argument, but not with the buffer as the current buffer.
 
 If there is no such live buffer, return nil."
-  (let ((predicate (or predicate #'identity))
-        (truename (abbreviate-file-name (file-truename filename))))
-    (or (let ((buf (get-file-buffer filename)))
-          (when (and buf (funcall predicate buf)) buf))
-        (let ((list (buffer-list)) found)
-          (while (and (not found) list)
-            (with-current-buffer (car list)
-              (if (and buffer-file-name
-                       (string= buffer-file-truename truename)
-                       (funcall predicate (current-buffer)))
-                  (setq found (car list))))
-            (setq list (cdr list)))
-          found)
-        (let* ((attributes (file-attributes truename))
-               (number (file-attribute-file-identifier attributes))
-               (list (buffer-list)) found)
-          (and buffer-file-numbers-unique
-               (car-safe number)       ;Make sure the inode is not just nil.
-               (while (and (not found) list)
-                 (with-current-buffer (car list)
-                   (if (and buffer-file-name
-                            (equal buffer-file-number number)
-                            ;; Verify this buffer's file number
-                            ;; still belongs to its file.
-                            (file-exists-p buffer-file-name)
-                            (equal (file-attributes buffer-file-truename)
-                                   attributes)
-                            (funcall predicate (current-buffer)))
-                       (setq found (car list))))
-                 (setq list (cdr list))))
-          found))))
+  (or (let ((buf (get-file-buffer filename)))
+        (when (and buf (or (not predicate) (funcall predicate buf))) buf))
+      (let ((truename (abbreviate-file-name (file-truename filename))))
+        (or
+         (let ((buf (get-truename-buffer truename)))
+           (when (and buf (buffer-local-value 'buffer-file-name buf)
+                      (or (not predicate) (funcall predicate buf)))
+             buf))
+         (let* ((attributes (file-attributes truename))
+                (number (file-attribute-file-identifier attributes)))
+           (and buffer-file-numbers-unique
+                (car-safe number)       ;Make sure the inode is not just nil.
+                (let ((buf (find-buffer 'buffer-file-number number)))
+                  (when (and buf (buffer-local-value 'buffer-file-name buf)
+                             ;; Verify this buffer's file number
+                             ;; still belongs to its file.
+                             (file-exists-p buffer-file-name)
+                             (equal (file-attributes buffer-file-truename)
+                                    attributes)
+                             (or (not predicate)
+                                 (funcall predicate (current-buffer))))
+                    buf))))))))
+
 \f
 (defcustom find-file-wildcards t
   "Non-nil means file-visiting commands should handle wildcards.

diff --git a/src/buffer.c b/src/buffer.c
index ea0c23192b7d25f613335e16519be95cf9eba5f6..73e9839f883e7e064615038e6f30f87e4829b48e 100644 (file)
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -519,8 +519,11 @@ See also `find-buffer-visiting'.  */)
   return Qnil;
 }
 
-Lisp_Object
-get_truename_buffer (register Lisp_Object filename)
+DEFUN ("get-truename-buffer", Fget_truename_buffer, Sget_truename_buffer, 1, 1, 0,
+       doc: /* Return the buffer with `file-truename' equal to FILENAME (a string).
+If there is no such live buffer, return nil.
+See also `find-buffer-visiting'.  */)
+  (register Lisp_Object filename)
 {
   register Lisp_Object tail, buf;
 
@@ -533,6 +536,22 @@ get_truename_buffer (register Lisp_Object filename)
   return Qnil;
 }
 
+DEFUN ("find-buffer", Ffind_buffer, Sfind_buffer, 2, 2, 0,
+       doc: /* Return the buffer with buffer-local VARIABLE equal to VALUE.
+              If there is no such live buffer, return nil.
+See also `find-buffer-visiting'.  */)
+  (Lisp_Object variable, Lisp_Object value)
+{
+  register Lisp_Object tail, buf;
+
+  FOR_EACH_LIVE_BUFFER (tail, buf)
+    {
+      if (!NILP (Fequal (value, Fbuffer_local_value(variable, buf))))
+       return buf;
+    }
+  return Qnil;
+}
+
 /* Run buffer-list-update-hook if Vrun_hooks is non-nil and BUF does
    not have buffer hooks inhibited.  */
 
@@ -6010,6 +6029,8 @@ There is no reason to change that value except for debugging purposes.  */);
   defsubr (&Sbuffer_list);
   defsubr (&Sget_buffer);
   defsubr (&Sget_file_buffer);
+  defsubr (&Sget_truename_buffer);
+  defsubr (&Sfind_buffer);
   defsubr (&Sget_buffer_create);
   defsubr (&Smake_indirect_buffer);
   defsubr (&Sgenerate_new_buffer_name);

diff --git a/src/filelock.c b/src/filelock.c
index c2b306ab47dff7713ac2560c5d244977de69dd00..9ce51c724b1db3cba7067b629da79a154a00f2c1 100644 (file)
--- a/src/filelock.c
+++ b/src/filelock.c
@@ -563,7 +563,7 @@ lock_file (Lisp_Object fn)
 
   /* See if this file is visited and has changed on disk since it was
      visited.  */
-  Lisp_Object subject_buf = get_truename_buffer (fn);
+  Lisp_Object subject_buf = Fget_truename_buffer (fn);
   if (!NILP (subject_buf)
       && NILP (Fverify_visited_file_modtime (subject_buf))
       && !NILP (Ffile_exists_p (fn))

diff --git a/src/lisp.h b/src/lisp.h
index ed1b007d4c54e67d976741c35e24c7d3b6198c15..efd36465e62aba6540bc085702622e9ab2d3eb64 100644 (file)
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4664,7 +4664,6 @@ extern void report_overlay_modification (Lisp_Object, Lisp_Object, bool,
                                          Lisp_Object, Lisp_Object, Lisp_Object);
 extern bool overlay_touches_p (ptrdiff_t);
 extern Lisp_Object other_buffer_safely (Lisp_Object);
-extern Lisp_Object get_truename_buffer (Lisp_Object);
 extern void init_buffer_once (void);
 extern void init_buffer (void);
 extern void syms_of_buffer (void);

diff --git a/test/manual/etags/c-src/emacs/src/lisp.h b/test/manual/etags/c-src/emacs/src/lisp.h
index aa8dc8c9a66d4de25a92804674fdd10340e46617..1946382827088eef19881f38509c56f6cd0cbd48 100644 (file)
--- a/test/manual/etags/c-src/emacs/src/lisp.h
+++ b/test/manual/etags/c-src/emacs/src/lisp.h
@@ -4075,7 +4075,6 @@ extern void report_overlay_modification (Lisp_Object, Lisp_Object, bool,
                                          Lisp_Object, Lisp_Object, Lisp_Object);
 extern bool overlay_touches_p (ptrdiff_t);
 extern Lisp_Object other_buffer_safely (Lisp_Object);
-extern Lisp_Object get_truename_buffer (Lisp_Object);
 extern void init_buffer_once (void);
 extern void init_buffer (int);
 extern void syms_of_buffer (void);