Improve performance of beginning/end-of-defun

taku0 · taku0 · commit 6d7093fb4a0b · 2022-11-19T18:10:14.000+09:00
Improve performance of `which-function': #180
diff --git a/swift-mode-beginning-of-defun.el b/swift-mode-beginning-of-defun.el
@@ -151,7 +151,7 @@ The cursor must be at the beginning of a statement."
        ((member (swift-mode:token:text token) '("var" "let"))
         (when (swift-mode:class-like-member-p) token))
        ((equal (swift-mode:token:text token) "case")
-        (swift-mode:backward-sexps-until '({))
+        (swift-mode:backward-sexps-until-open-curly-brace)
         (swift-mode:beginning-of-statement)
         (let ((parent-token (swift-mode:find-defun-keyword-simple)))
           (when (equal (swift-mode:token:text parent-token) "enum")
@@ -201,7 +201,7 @@ The cursor must be at the beginning of a statement."
 Also return t if the cursor is on a global declaration.
 Return nil otherwise."
   (or
-   (let ((parent (swift-mode:backward-sexps-until '({))))
+   (let ((parent (swift-mode:backward-sexps-until-open-curly-brace)))
      (eq (swift-mode:token:type parent) 'outside-of-buffer))
    (progn
      (swift-mode:beginning-of-statement)
@@ -1391,7 +1391,7 @@ of ancestors."
   (if (bobp)
       nil
     (let ((name-token (swift-mode:current-defun-name-token)))
-      (swift-mode:backward-sexps-until '({))
+      (swift-mode:backward-sexps-until-open-curly-brace)
       (if name-token
           (cons name-token (swift-mode:current-defun-name-token-list))
         (swift-mode:current-defun-name-token-list)))))
diff --git a/swift-mode-indent.el b/swift-mode-indent.el
@@ -653,7 +653,7 @@ Also used for regexes."
      ;; After "in" for anonymous function parameters
      ((eq previous-type 'anonymous-function-parameter-in)
       (goto-char (swift-mode:token:start previous-token))
-      (swift-mode:backward-sexps-until '({))
+      (swift-mode:backward-sexps-until-open-curly-brace)
       (swift-mode:calculate-indent-after-open-curly-brace
        swift-mode:basic-offset))
 
@@ -1353,6 +1353,24 @@ is the symbol `any', it matches all tokens."
       (setq text (swift-mode:token:text parent)))
     parent))
 
+(defun swift-mode:backward-sexps-until-open-curly-brace ()
+  "Backward sexps until an open curly brace appears.
+Return the brace token.
+When this function returns, the cursor is at the start of the token.
+
+If there is no open curly braces, return `outside-of-buffer' token.
+
+This is optimized version of (swift-mode:backward-sexps-until '({}))."
+  (let* ((parent-position (nth 1 (syntax-ppss))))
+    (while (and parent-position
+                (and (goto-char parent-position)
+                     (not (eq (char-after) ?{))))
+      (setq parent-position (nth 1 (syntax-ppss))))
+    (if (eq (char-after) ?{)
+        (save-excursion (swift-mode:forward-token))
+      (goto-char (point-min))
+      (swift-mode:backward-token))))
+
 (defun swift-mode:align-with-next-token (parent &optional offset)
   "Return indentation with the PARENT and OFFSET."
   (let ((parent-end (swift-mode:token:end parent)))
