ACPT-961: Improve Config readData() (when config cache is clean)

* using str_contains ahead of time (so we don't have to call the methods or run regex when we know it wouldn't match) (about 5-10% faster)
* using array_walk_recursive which is a lot easier to read and is 5-10% faster
* caching environmental variables config (we don't need to reload environment variables for each website)

Author: JacobBrownAustin

app/code/Magento/Config/App/Config/Source/EnvironmentConfigSource.php

@@ -33,6 +33,20 @@ class EnvironmentConfigSource implements ConfigSourceInterface
      */
     private $placeholder;
 
+    /**
+     * cache for loadConfig()
+     *
+     * @var array|null
+     */
+    private $loadConfigCache;
+
+    /**
+     * cache for loadConfig()
+     *
+     * @var string|null
+     */
+    private $loadConfigCacheEnv;
+
     /**
      * @param ArrayManager $arrayManager
      * @param PlaceholderFactory $placeholderFactory
@@ -57,27 +71,32 @@ public function get($path = '')
 
     /**
      * Loads config from environment variables.
+     * Caching the result for when this method is called multiple times.
+     * The environment variables don't change in run time,  so it is safe to cache.
      *
      * @return array
      */
     private function loadConfig()
     {
         $config = [];
-
+        // phpcs:disable Magento2.Security.Superglobal
         $environmentVariables = $_ENV;
-
+        // phpcs:enable
+        if (null !== $this->loadConfigCache && $this->loadConfigCacheEnv === $environmentVariables) {
+            return $this->loadConfigCache;
+        }
         foreach ($environmentVariables as $template => $value) {
             if (!$this->placeholder->isApplicable($template)) {
                 continue;
             }
-
             $config = $this->arrayManager->set(
                 $this->placeholder->restore($template),
                 $config,
                 $value
             );
         }
-
+        $this->loadConfigCache = $config;
+        $this->loadConfigCacheEnv = $environmentVariables;
         return $config;
     }
 }

app/code/Magento/Store/Model/Config/Placeholder.php

@@ -43,48 +43,30 @@ public function __construct(\Magento\Framework\App\RequestInterface $request, $u
      *
      * @param array $data
      * @return array
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
      */
     public function process(array $data = [])
     {
-        // check provided arguments
         if (empty($data)) {
             return [];
         }
-
-        // initialize $pointer, $parents and $level variable
-        reset($data);
-        $pointer = &$data;
-        $parents = [];
-        $level   = 0;
-
-        while ($level >= 0) {
-            $current = &$pointer[key($pointer)];
-            if (is_array($current)) {
-                reset($current);
-                $parents[$level] = &$pointer;
-                $pointer         = &$current;
-                $level++;
-            } else {
-                $current = $this->_processPlaceholders($current, $data);
-
-                // move pointer of last queue layer to next element
-                // or remove layer if all path elements were processed
-                while ($level >= 0 && next($pointer) === false) {
-                    $level--;
-                    // removal of last element of $parents is skipped here for better performance
-                    // on next iteration that element will be overridden
-                    $pointer = &$parents[$level];
+        array_walk_recursive(
+            $data,
+            function (&$value, $key, $data) {
+                if (is_string($value) && str_contains($value, '{')) {  // If _getPlaceholder() would do nothing, skip
+                    $value = $this->_processPlaceholders($value, $data);
                 }
-            }
-        }
-
+            },
+            $data
+        );
         return $data;
     }
 
     /**
      * Process array data recursively
      *
      * @deprecated 101.0.4 This method isn't used in process() implementation anymore
+     * @see process()
      *
      * @param array &$data
      * @param string $path
@@ -179,6 +161,7 @@ protected function _getValue($path, array $data)
      * Set array value by path
      *
      * @deprecated 101.0.4 This method isn't used in process() implementation anymore
+     * @see process()
      *
      * @param array &$container
      * @param string $path
@@ -187,7 +170,7 @@ protected function _getValue($path, array $data)
      */
     protected function _setValue(array &$container, $path, $value)
     {
-        $segments       = explode('/', (string)$path);
+        $segments = explode('/', (string)$path);
         $currentPointer = &$container;
         foreach ($segments as $segment) {
             if (!isset($currentPointer[$segment])) {