From c3ac8b4ef89196c91103374421de675eeca21632 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gildas=20Qu=C3=A9m=C3=A9ner?= <gildas.quemener@gmail.com>
Date: Fri, 19 Feb 2021 14:02:52 +0100
Subject: [PATCH] [Messenger] Locate exactly one handler

Related to https://github.com/symfony/symfony/issues/36958
---
 .../MultipleHandlersForMessageException.php   | 20 +++++
 .../Handler/ExactlyOneHandlerLocator.php      | 42 +++++++++++
 .../Handler/ExactlyOneHandlerLocatorTest.php  | 75 +++++++++++++++++++
 3 files changed, 137 insertions(+)
 create mode 100644 src/Symfony/Component/Messenger/Exception/MultipleHandlersForMessageException.php
 create mode 100644 src/Symfony/Component/Messenger/Handler/ExactlyOneHandlerLocator.php
 create mode 100644 src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php

diff --git a/src/Symfony/Component/Messenger/Exception/MultipleHandlersForMessageException.php b/src/Symfony/Component/Messenger/Exception/MultipleHandlersForMessageException.php
new file mode 100644
index 0000000000000..f62f428e4f4c4
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Exception/MultipleHandlersForMessageException.php
@@ -0,0 +1,20 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Exception;
+
+class MultipleHandlersForMessageException extends LogicException
+{
+    public function __construct(string $messageType)
+    {
+        parent::__construct(sprintf('Multiple handlers for message "%s"', $messageType));
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Handler/ExactlyOneHandlerLocator.php b/src/Symfony/Component/Messenger/Handler/ExactlyOneHandlerLocator.php
new file mode 100644
index 0000000000000..2fae1df95b3eb
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Handler/ExactlyOneHandlerLocator.php
@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Handler;
+
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Exception\MultipleHandlersForMessageException;
+use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
+
+final class ExactlyOneHandlerLocator implements HandlersLocatorInterface
+{
+    private $handlers;
+
+    public function __construct(array $handlers)
+    {
+        foreach ($handlers as $type => $h) {
+            if (\count($h) > 1) {
+                throw new MultipleHandlersForMessageException($type);
+            }
+        }
+
+        $this->handlers = $handlers;
+    }
+
+    public function getHandlers(Envelope $envelope): iterable
+    {
+        $type = \get_class($envelope->getMessage());
+        if (!isset($this->handlers[$type])) {
+            throw new NoHandlerForMessageException($type);
+        }
+
+        yield $this->handlers[$type][0];
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php b/src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php
new file mode 100644
index 0000000000000..5e57cd157c015
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php
@@ -0,0 +1,75 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests\Handler;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Handler\HandlerDescriptor;
+use Symfony\Component\Messenger\Stamp\ReceivedStamp;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+use Symfony\Component\Messenger\Handler\HandlersLocatorInterface;
+use Symfony\Component\Messenger\Handler\ExactlyOneHandlerLocator;
+use Symfony\Component\Messenger\Exception\MultipleHandlersForMessageException;
+use Symfony\Bundle\FrameworkBundle\Tests\Fixtures\Messenger\SecondMessage;
+use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
+
+class ExactlyOneHandlerLocatorTest extends TestCase
+{
+    public function testItIsAHandlerLocator(): void
+    {
+        $this->assertInstanceOf(HandlersLocatorInterface::class, new ExactlyOneHandlerLocator([]));
+    }
+
+    public function testItProvidesAHandler(): void
+    {
+        $handler1 = $this->createPartialMock(ExactlyOneHandlerLocatorTestCallable::class, ['__invoke']);
+        $handler2 = $this->createPartialMock(ExactlyOneHandlerLocatorTestCallable::class, ['__invoke']);
+
+        $locator = new ExactlyOneHandlerLocator([
+            DummyMessage::class => [$handler1],
+            SecondMessage::class => [$handler2],
+        ]);
+
+        $this->assertSame([$handler1], iterator_to_array($locator->getHandlers(
+            new Envelope(new DummyMessage('Body'), [new ReceivedStamp('transportName')])
+        )));
+    }
+
+    public function testItThrowsAnExceptionWhenMultipleHandlersMatchesMessage()
+    {
+        $this->expectException(MultipleHandlersForMessageException::class);
+
+        new ExactlyOneHandlerLocator([
+            DummyMessage::class => [
+                $this->createPartialMock(ExactlyOneHandlerLocatorTestCallable::class, ['__invoke']),
+                $this->createPartialMock(ExactlyOneHandlerLocatorTestCallable::class, ['__invoke']),
+            ],
+        ]);
+    }
+
+    public function testItThrowsExceptionWhenNoHandlerMatchesMessage(): void
+    {
+        $this->expectException(NoHandlerForMessageException::class);
+
+        $locator = new ExactlyOneHandlerLocator([]);
+        iterator_to_array($locator->getHandlers(
+            new Envelope(new DummyMessage('Body'), [new ReceivedStamp('transportName')])
+        ));
+    }
+}
+
+class ExactlyOneHandlerLocatorTestCallable
+{
+    public function __invoke()
+    {
+    }
+}