From 1e641d657832bb5fe437f578a795039272eb2cd7 Mon Sep 17 00:00:00 2001
From: David Grudl <david@grudl.com>
Date: Mon, 25 Nov 2024 11:38:08 +0100
Subject: [PATCH] creating lazy services in PHP 8.4 WIP

---
 src/DI/Container.php              |  7 ++++++-
 src/DI/Extensions/DIExtension.php | 28 ++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/DI/Container.php b/src/DI/Container.php
index d72639a63..c4aa29bbe 100644
--- a/src/DI/Container.php
+++ b/src/DI/Container.php
@@ -32,6 +32,9 @@ class Container
 	/** @var array[]  type => (high, low, no) => services */
 	protected array $wiring = [];
 
+	/** @var string[]  service name => class */
+	protected array $lazy = [];
+
 	/** @var object[]  service name => instance */
 	private array $instances = [];
 
@@ -215,7 +218,9 @@ public function createService(string $name): object
 		if ($callback = ($this->factories[$name] ?? null)) {
 			$service = $this->preventDeadLock($name, fn() => $callback());
 		} elseif (isset($this->methods[$method])) {
-			$service = $this->preventDeadLock($name, fn() => $this->$method());
+			$service = isset($this->lazy[$name])
+				? (new \ReflectionClass($this->lazy[$name]))->newLazyProxy($this->$method(...))
+				: $this->preventDeadLock($name, fn() => $this->$method());
 		} else {
 			throw new MissingServiceException(sprintf("Service '%s' not found.", $name));
 		}
diff --git a/src/DI/Extensions/DIExtension.php b/src/DI/Extensions/DIExtension.php
index 5b789cffa..7775aff9b 100644
--- a/src/DI/Extensions/DIExtension.php
+++ b/src/DI/Extensions/DIExtension.php
@@ -10,6 +10,8 @@
 namespace Nette\DI\Extensions;
 
 use Nette;
+use Nette\DI\Definitions\ServiceDefinition;
+use Nette\PhpGenerator as Php;
 use Tracy;
 
 
@@ -36,6 +38,7 @@ public function __construct(bool $debugMode = false)
 			public array $excluded = [];
 			public ?string $parentClass = null;
 			public object $export;
+			public bool $lazy = false;
 		};
 		$this->config->export = new class {
 			public bool $parameters = true;
@@ -62,6 +65,7 @@ public function afterCompile(Nette\PhpGenerator\ClassType $class): void
 			$class->setExtends($this->config->parentClass);
 		}
 
+		$this->initializeLazy($class);
 		$this->restrictParameters($class);
 		$this->restrictTags($class);
 		$this->restrictTypes($class);
@@ -75,6 +79,30 @@ public function afterCompile(Nette\PhpGenerator\ClassType $class): void
 	}
 
 
+	private function initializeLazy(Nette\PhpGenerator\ClassType $class): void
+	{
+		if (!$this->config->lazy || PHP_VERSION_ID < 80400) {
+			return;
+		}
+
+		$classes = [];
+		foreach ($this->getContainerBuilder()->getDefinitions() as $name => $def) {
+			if ($def instanceof ServiceDefinition
+				&& is_string($def->getEntity())
+				&& ($rc = new \ReflectionClass($def->getEntity()))
+				&& !$rc->isInternal()
+			) {
+				$classes[$name] = $rc->getName();
+			}
+		}
+
+		(new Php\ClassManipulator($class))
+			->inheritProperty('lazy')
+			->setComment(null)
+			->setValue($classes);
+	}
+
+
 	private function restrictParameters(Nette\PhpGenerator\ClassType $class): void
 	{
 		if (!$this->config->export->parameters) {