minor symfony#2343 [TwigComponent] Improve BlockStack performances (smnandre)

This PR was merged into the 2.x branch.

Discussion
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[TwigComponent] Improve BlockStack performances

BlockStack Quick Optimization
Minor change with major impact

(test app with a component rendered 5000 times in the main part of the page)

<img width="971" alt="Capture d’écran 2024-11-06 à 03 09 43" src="https://github.com/user-attachments/assets/367ef408-ade8-4b3b-abab-23960f7ca094">

Commits
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18bc31b [TwigComponent] Improve BlockStack performances

Author: smnandre

src/TwigComponent/src/BlockStack.php

@@ -28,9 +28,15 @@ final class BlockStack
      */
     private array $stack;
 
+    /**
+     * @var array<class-string, int>
+     */
+    private static array $templateIndexStack = [];
+
     public function convert(array $blocks, int $targetEmbeddedTemplateIndex): array
     {
         $newBlocks = [];
+        $hostEmbeddedTemplateIndex = null;
         foreach ($blocks as $blockName => $block) {
             // Keep already converted outer blocks untouched
             if (str_starts_with($blockName, self::OUTER_BLOCK_PREFIX)) {
@@ -41,7 +47,7 @@ public function convert(array $blocks, int $targetEmbeddedTemplateIndex): array
             // Determine the location of the block where it is defined in the host Template.
             // Each component has its own embedded template. That template's index uniquely
             // identifies the block definition.
-            $hostEmbeddedTemplateIndex = $this->findHostEmbeddedTemplateIndex();
+            $hostEmbeddedTemplateIndex ??= $this->findHostEmbeddedTemplateIndex();
 
             // Change the name of outer blocks to something unique so blocks of nested components aren't overridden,
             // which otherwise might cause a recursion loop when nesting components.
@@ -69,12 +75,10 @@ private function findHostEmbeddedTemplateIndex(): int
     {
         $backtrace = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS | \DEBUG_BACKTRACE_PROVIDE_OBJECT);
 
-        $componentTemplateClassName = null;
-
         foreach ($backtrace as $trace) {
             if (isset($trace['object']) && $trace['object'] instanceof Template) {
                 $classname = $trace['object']::class;
-                $templateIndex = $this->getTemplateIndexFromTemplateClassname($classname);
+                $templateIndex = self::getTemplateIndexFromTemplateClassname($classname);
                 if ($templateIndex) {
                     // If there's no template index, then we're in a component template
                     // and we need to go up until we find the embedded template
@@ -93,7 +97,7 @@ private function findCallingEmbeddedTemplateIndex(): int
 
         foreach ($backtrace as $trace) {
             if (isset($trace['object']) && $trace['object'] instanceof Template) {
-                return $this->getTemplateIndexFromTemplateClassname($trace['object']::class);
+                return self::getTemplateIndexFromTemplateClassname($trace['object']::class);
             }
         }
     }
@@ -108,7 +112,7 @@ private function findHostEmbeddedTemplateIndexFromCaller(): int
         foreach ($backtrace as $trace) {
             if (isset($trace['object']) && $trace['object'] instanceof Template) {
                 $classname = $trace['object']::class;
-                $templateIndex = $this->getTemplateIndexFromTemplateClassname($classname);
+                $templateIndex = self::getTemplateIndexFromTemplateClassname($classname);
                 if (null === $renderer) {
                     if ($templateIndex) {
                         // This class is an embedded template.
@@ -139,8 +143,8 @@ private function findHostEmbeddedTemplateIndexFromCaller(): int
         return 0;
     }
 
-    private function getTemplateIndexFromTemplateClassname(string $classname): int
+    private static function getTemplateIndexFromTemplateClassname(string $classname): int
     {
-        return (int) substr($classname, strrpos($classname, '___') + 3);
+        return self::$templateIndexStack[$classname] ??= (int) substr($classname, strrpos($classname, '___') + 3);
     }
 }