FEATURE: Fusion performance optimization (lazy Component props)

Neos.Fusion/Classes/FusionObjects/ComponentImplementation.php

@@ -11,6 +11,7 @@
  * source code.
  */
 
+use Neos\Fusion\FusionObjects\Helpers\LazyProps;
 
 /**
  * A Fusion Component-Object
@@ -51,37 +52,32 @@ public function evaluate()
      * @param array $context
      * @return array
      */
-    protected function prepare($context)
+    protected function prepare(array $context): array
     {
-        $context['props'] = $this->getProps();
+        $context['props'] = $this->getProps($context);
         return $context;
     }
 
     /**
      * Calculate the component props
      *
-     * @return array
+     * @param array $context
+     * @return \ArrayAccess
      */
-    protected function getProps()
+    protected function getProps(array $context): \ArrayAccess
     {
         $sortedChildFusionKeys = $this->sortNestedFusionKeys();
-        $props = [];
-        foreach ($sortedChildFusionKeys as $key) {
-            try {
-                $props[$key] = $this->fusionValue($key);
-            } catch (\Exception $e) {
-                $props[$key] = $this->runtime->handleRenderingException($this->path . '/' . $key, $e);
-            }
-        }
+        $props = new LazyProps($this, $this->path, $this->runtime, $sortedChildFusionKeys, $context);
         return $props;
     }
+
     /**
      * Evaluate the renderer with the give context and return
      *
-     * @param $context
+     * @param array $context
      * @return mixed
      */
-    protected function render($context)
+    protected function render(array $context)
     {
         $this->runtime->pushContextArray($context);
         $result = $this->runtime->render($this->path . '/renderer');

Neos.Fusion/Classes/FusionObjects/Helpers/LazyProps.php

@@ -0,0 +1,117 @@
+<?php
+
+namespace Neos\Fusion\FusionObjects\Helpers;
+
+use Neos\Flow\Annotations as Flow;
+use Neos\Fusion\Core\Runtime;
+
+/**
+ * @Flow\Proxy(false)
+ */
+final class LazyProps implements \ArrayAccess, \Iterator
+{
+
+    /**
+     * @var array
+     */
+    private $valueCache = [];
+
+    /**
+     * @var string
+     */
+    private $parentPath;
+
+    /**
+     * @var Runtime
+     */
+    private $runtime;
+
+    /**
+     * Index of keys
+     *
+     * @var array
+     */
+    private $keys;
+
+    /**
+     * @var object
+     */
+    private $fusionObject;
+
+    /**
+     * @var array
+     */
+    private $effectiveContext;
+
+    public function __construct(
+        object $fusionObject,
+        string $parentPath,
+        Runtime $runtime,
+        array $keys,
+        array $effectiveContext
+    ) {
+        $this->fusionObject = $fusionObject;
+        $this->parentPath = $parentPath;
+        $this->runtime = $runtime;
+        $this->keys = array_flip($keys);
+        $this->effectiveContext = $effectiveContext;
+    }
+
+    public function offsetExists($path)
+    {
+        return isset($this->keys[$path]);
+    }
+
+    public function offsetGet($path)
+    {
+        if (!isset($this->valueCache[$path])) {
+            $this->runtime->pushContextArray($this->effectiveContext);
+            try {
+                $this->valueCache[$path] = $this->runtime->evaluate($this->parentPath . '/' . $path,
+                    $this->fusionObject);
+            } finally {
+                $this->runtime->popContext();
+            }
+        }
+        return $this->valueCache[$path];
+    }
+
+    public function offsetSet($path, $value)
+    {
+        // NOOP
+    }
+
+    public function offsetUnset($path)
+    {
+        // NOOP
+    }
+
+    public function current()
+    {
+        $path = key($this->keys);
+        if ($path === null) {
+            return null;
+        }
+        return $this->offsetGet($path);
+    }
+
+    public function next()
+    {
+        next($this->keys);
+    }
+
+    public function key()
+    {
+        return key($this->keys);
+    }
+
+    public function valid()
+    {
+        return current($this->keys) !== false;
+    }
+
+    public function rewind()
+    {
+        reset($this->keys);
+    }
+}

Neos.Fusion/Tests/Functional/FusionObjects/ComponentTest.php

@@ -56,4 +56,14 @@ public function componentSandboxRenderer()
         $view->setFusionPath('component/sandboxRenderer');
         self::assertEquals('Hello ', $view->render());
     }
+
+    /**
+     * @test
+     */
+    public function componentLazyRenderer()
+    {
+        $view = $this->buildView();
+        $view->setFusionPath('component/lazyRenderer');
+        self::assertEquals('Hello', $view->render());
+    }
 }

Neos.Fusion/Tests/Functional/FusionObjects/Fixtures/Fusion/Component.fusion

@@ -40,3 +40,11 @@ component.sandboxRenderer = Neos.Fusion:Component {
     }
   }
 }
+
+component.lazyRenderer = Neos.Fusion:Component {
+  a = 'Hello'
+  // This prop is not evaluated, since it is not used - otherwise the test would fail
+  b = Neos.Fusion:NotImplemented
+
+  renderer = ${props.a}
+}