[Clock] Add Clock::now(), get() and with()

src/Symfony/Component/Clock/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Add `ClockAwareTrait` to help write time-sensitive classes
+ * Add `Clock::now()`, `Clock::get()` and  `Clock::with()`
 
 6.2
 ---

src/Symfony/Component/Clock/Clock.php

@@ -0,0 +1,58 @@
+<?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\Clock;
+
+use Psr\Clock\ClockInterface;
+
+/**
+ * A global clock.
+ *
+ * Note that you should prefer injecting a ClockInterface or using
+ * ClockAwareTrait when possible instead of using this class.
+ *
+ * Defined as enum to be final and non-instantiable.
+ */
+enum Clock
+{
+    public static function now(): \DateTimeImmutable
+    {
+        return self::get()->now();
+    }
+
+    public static function with(ClockInterface $clock, callable $callback, mixed ...$arguments): mixed
+    {
+        $prevClock = self::get($clock);
+
+        try {
+            return $callback(...$arguments);
+        } finally {
+            self::get($prevClock);
+        }
+    }
+
+    /**
+     * Returns the current clock, or the previous one if a new clock is passed as argument.
+     */
+    public static function get(ClockInterface $newClock = null): ClockInterface
+    {
+        static $clock;
+
+        if (!$newClock) {
+            return $clock ??= new NativeClock();
+        }
+
+        $prevClock = $clock ?? new NativeClock();
+        $clock = $newClock;
+
+        return $prevClock;
+    }
+}

src/Symfony/Component/Clock/Tests/ClockTest.php

@@ -0,0 +1,31 @@
+<?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\Clock\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Clock\Clock;
+use Symfony\Component\Clock\MockClock;
+use Symfony\Component\Clock\NativeClock;
+
+class ClockTest extends TestCase
+{
+    public function testClock()
+    {
+        $this->assertInstanceOf(\DateTimeImmutable::class, Clock::now());
+        $this->assertInstanceOf(NativeClock::class, Clock::get());
+
+        $clock = new MockClock();
+
+        $this->assertSame([123, $clock], Clock::with($clock, fn ($arg) => [$arg, Clock::get()], 123));
+        $this->assertInstanceOf(NativeClock::class, Clock::get());
+    }
+}