Add php-mode-syntax-propertize-extend-region-limit for optimize syntax propertization

Author: zonuexe

Diff for: CHANGELOG.md

@@ -11,13 +11,17 @@ All notable changes of the PHP Mode 1.19.1 release series are documented in this
  * Add `php-imenu-generic-expression-default` for default value or `php-imenu-generic-expression`
    * Add `php-imenu-generic-expression-legacy` for compatibility
    * Add `php-imenu-generic-expression-simple` for simple display
+ * Add custom variables
+   * Add `php-mode-syntax-propertize-extend-region-limit` for optimize syntax propertization
+     * The number of search characters used to find the starting point of Heredoc and Nowdoc
 
 ### Changed
 
  * Optimized propertize process ([#669])
    * Reimoplement `php-syntax-propertize-function` using `syntax-propertize-rules`
    * Make propertize PHP 8 `#[Attribute]` always enabled
    * Changed grouping of `php-heredoc-start-re`
+   * Use limits on `php-mode-syntax-propertize-extend-region-limit` variable to find the starting point of Heredoc and Nowdoc
  * Re-organized `php-imenu-generic-expression`
    * Added `Import`, `Constants` and `Properties`
    * Removed `Anonymous Functions`

Diff for: lisp/php-mode.el

@@ -284,6 +284,15 @@ In that case set to `NIL'."
   :tag "PHP Mode Enable Project Local Variable"
   :type 'boolean)
 
+(defcustom php-mode-syntax-propertize-extend-region-limit (* 100 syntax-propertize-chunk-size)
+  "Boundary value of the number of search characters to propertize syntax.
+
+Smaller values can improve performance with large buffers.
+If the value is too small, the syntax will not be displayed properly."
+  :group 'php-mode
+  :tag "PHP Mode Syntax Propertize Extend Region Limit"
+  :type 'integer)
+
 (defconst php-mode-cc-vertion
   (eval-when-compile c-version))
 
@@ -987,22 +996,24 @@ this ^ lineup"
 
 (defun php-syntax-propertize-extend-region (start end)
   "Extend the propertize region if START or END falls inside a PHP heredoc."
-  (let ((pair (cons start end)))
+  (let ((pair (cons start end))
+        (limit (max syntax-propertize-chunk-size php-mode-syntax-propertize-extend-region-limit))
+        new-start new-end maybe)
     (when (not (member pair php-mode--propertize-extend-region-current))
       ;; re-search functions may trigger
       ;; syntax-propertize-extend-region-functions to be called again, which in
       ;; turn call this to be called again.
       (push pair php-mode--propertize-extend-region-current)
       (unwind-protect
-          (let (new-start new-end)
+          (progn
             (goto-char start)
-            (when (re-search-backward php-heredoc-start-re nil t)
-              (let ((maybe (point)))
-                (when (and (re-search-forward (php-heredoc-end-re (match-string 0)) nil t)
-                           (> (point) start))
-                  (setq new-start maybe))))
+            (when (re-search-backward php-heredoc-start-re limit t)
+              (setq maybe (point))
+              (when (and (re-search-forward (php-heredoc-end-re (match-string 0)) nil t)
+                         (> (point) start))
+                (setq new-start maybe)))
             (goto-char end)
-            (when (re-search-backward php-heredoc-start-re nil t)
+            (when (re-search-backward php-heredoc-start-re limit t)
               (if (re-search-forward (php-heredoc-end-re (match-string 0)) nil t)
                   (when (> (point) end)
                     (setq new-end (point)))