* lisp/isearch.el (search-within-boundaries): Optimize (bug#78520).

For non-subregexp case, search for the first match and continue
from its position.  This avoids unnecessary scan for all text properties
until the first match.  When nothing is found, skip the entire body.

1 files changed, 27 insertions, 14 deletions

diff --git a/lisp/isearch.el b/lisp/isearch.el
index 6b759f4ad3e..68519b7a820 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -4610,9 +4610,7 @@ defaults to the value of `isearch-search-fun-default' when nil."
 (defun search-within-boundaries ( search-fun get-fun next-fun
                                   string &optional bound noerror count)
   (let* ((old (point))
-         ;; Check if point is already on the property.
-         (beg (when (funcall get-fun old) old))
-         end found (i 0)
+         beg end found skip (i 0)
          (subregexp
           (and isearch-regexp
                (save-match-data
@@ -4622,18 +4620,33 @@ defaults to the value of `isearch-search-fun-default' when nil."
                      (when (subregexp-context-p string (match-beginning 0))
                        ;; The ^/$ is not inside a char-range or escaped.
                        (throw 'subregexp t))))))))
-    ;; Otherwise, try to search for the next property.
-    (unless beg
-      (setq beg (funcall next-fun old))
-      (when beg
-        (if (or (null bound)
-                (if isearch-forward
-                    (< beg bound)
-                  (> beg bound)))
-            (goto-char beg)
-          (setq beg nil))))
+
+    ;; Optimization for non-subregexp case to set the initial position
+    ;; on the first match assuming there is no need to check boundaries
+    ;; for a search string/regexp without anchors (bug#78520).
+    (unless subregexp
+      (save-match-data
+        (if (funcall (or search-fun (isearch-search-fun-default))
+                     string bound noerror count)
+            (goto-char (if isearch-forward (match-beginning 0) (match-end 0)))
+          (setq skip t))))
+
+    (unless skip
+      ;; Check if point is already on the property.
+      (setq beg (when (funcall get-fun (point)) (point)))
+      ;; Otherwise, try to search for the next property.
+      (unless beg
+        (setq beg (funcall next-fun (point)))
+        (when beg
+          (if (or (null bound)
+                  (if isearch-forward
+                      (< beg bound)
+                    (> beg bound)))
+              (goto-char beg)
+            (setq beg nil)))))
+
     ;; Non-nil `beg' means there are more properties.
-    (while (and beg (not found))
+    (while (and beg (not found) (not skip))
       ;; Search for the end of the current property.
       (setq end (funcall next-fun beg))
       ;; Handle ^/$ specially by matching in a temporary buffer.