FNSR - Fiber pool

Author: ondrejmirtes

src/Analyser/ExpressionResultStorage.php

@@ -3,8 +3,10 @@
 namespace PHPStan\Analyser;
 
 use Fiber;
+use PhpParser\Node;
 use PhpParser\Node\Expr;
 use PHPStan\Analyser\Fiber\BeforeScopeForExprRequest;
+use PHPStan\Analyser\Fiber\ParkFiberRequest;
 use SplObjectStorage;
 
 final class ExpressionResultStorage
@@ -13,9 +15,12 @@ final class ExpressionResultStorage
 	/** @var SplObjectStorage<Expr, Scope> */
 	private SplObjectStorage $scopes;
 
-	/** @var array<array{fiber: Fiber<mixed, Scope, null, BeforeScopeForExprRequest>, request: BeforeScopeForExprRequest}> */
+	/** @var array<array{fiber: Fiber<mixed, Scope|array{callable(Node $node, Scope $scope): void, Node, Scope}, null, BeforeScopeForExprRequest|ParkFiberRequest>, request: BeforeScopeForExprRequest}> */
 	public array $pendingFibers = [];
 
+	/** @var list<Fiber<mixed, Scope|array{callable(Node $node, Scope $scope): void, Node, Scope}, null, BeforeScopeForExprRequest|ParkFiberRequest>> */
+	public array $parkedFibers = [];
+
 	public function __construct()
 	{
 		$this->scopes = new SplObjectStorage();

src/Analyser/Fiber/FiberNodeScopeResolver.php

@@ -11,6 +11,8 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\ShouldNotHappenException;
+use function array_pop;
+use function count;
 use function get_debug_type;
 
 #[AutowiredService(as: FiberNodeScopeResolver::class)]
@@ -31,20 +33,28 @@ protected function callNodeCallback(
 			$nodeCallback($node, $scope->toFiberScope());
 			return;
 		}
-		$fiber = new Fiber(static function () use ($node, $scope, $nodeCallback) {
-			$nodeCallback($node, $scope->toFiberScope());
-		});
-		$request = $fiber->start();
+		if (count($storage->parkedFibers) > 0) {
+			$fiber = array_pop($storage->parkedFibers);
+			$request = $fiber->resume([$nodeCallback, $node, $scope]);
+		} else {
+			$fiber = new Fiber(static function () use ($node, $scope, $nodeCallback) {
+				while (true) { // @phpstan-ignore while.alwaysTrue
+					$nodeCallback($node, $scope->toFiberScope());
+					[$nodeCallback, $node, $scope] = Fiber::suspend(new ParkFiberRequest());
+				}
+			});
+			$request = $fiber->start();
+		}
 		$this->runFiberForNodeCallback($storage, $fiber, $request);
 	}
 
 	/**
-	 * @param Fiber<mixed, Scope, null, BeforeScopeForExprRequest> $fiber
+	 * @param Fiber<mixed, Scope|array{callable(Node $node, Scope $scope): void, Node, Scope}, null, BeforeScopeForExprRequest|ParkFiberRequest> $fiber
 	 */
 	private function runFiberForNodeCallback(
 		ExpressionResultStorage $storage,
 		Fiber $fiber,
-		?BeforeScopeForExprRequest $request,
+		BeforeScopeForExprRequest|ParkFiberRequest|null $request,
 	): void
 	{
 		while (!$fiber->isTerminated()) {
@@ -61,6 +71,10 @@ private function runFiberForNodeCallback(
 				];
 				return;
 			}
+			if ($request instanceof ParkFiberRequest) {
+				$storage->parkedFibers[] = $fiber;
+				return;
+			}
 
 			throw new ShouldNotHappenException(
 				'Unknown fiber suspension: ' . get_debug_type($request),

src/Analyser/Fiber/ParkFiberRequest.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser\Fiber;
+
+final class ParkFiberRequest
+{
+
+}