Callable parameter injection

This is like what we have to DI and classes, but for callables.

The motivating factor is to get rid of *service locators* in the `boot`
method of apps as a new pattern is about to emerge where we have lots of
`query` calls on the app or server container in order to fetch some
services.

With this little helper it's possible to call another (public) method
and magically have everything injected.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

2 files changed, 90 insertions, 3 deletions

diff --git a/tests/lib/AppFramework/Bootstrap/FunctionInjectorTest.php b/tests/lib/AppFramework/Bootstrap/FunctionInjectorTest.php
new file mode 100644
index 00000000000..cd2332b0588
--- /dev/null
+++ b/tests/lib/AppFramework/Bootstrap/FunctionInjectorTest.php
@@ -0,0 +1,84 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace lib\AppFramework\Bootstrap;
+
+use OC\AppFramework\Bootstrap\FunctionInjector;
+use OC\AppFramework\Utility\SimpleContainer;
+use Test\TestCase;
+
+interface Foo {
+}
+
+class FunctionInjectorTest extends TestCase {
+
+	/** @var SimpleContainer */
+	private $container;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->container = new SimpleContainer();
+	}
+
+	public function testInjectFnNotRegistered(): void {
+		$this->expectException(\OCP\AppFramework\QueryException::class);
+
+		(new FunctionInjector($this->container))->injectFn(static function (Foo $p1): void {
+		});
+	}
+
+	public function testInjectFnNotRegisteredButNullable(): void {
+		(new FunctionInjector($this->container))->injectFn(static function (?Foo $p1): void {
+		});
+
+		// Nothing to assert. No errors means everything is fine.
+		$this->addToAssertionCount(1);
+	}
+
+	public function testInjectFnByType(): void {
+		$this->container->registerService(Foo::class, function () {
+			$this->addToAssertionCount(1);
+			return new class implements Foo {
+			};
+		});
+
+		(new FunctionInjector($this->container))->injectFn(static function (Foo $p1): void {
+		});
+
+		// Nothing to assert. No errors means everything is fine.
+		$this->addToAssertionCount(1);
+	}
+
+	public function testInjectFnByName(): void {
+		$this->container->registerParameter('test', 'abc');
+
+		(new FunctionInjector($this->container))->injectFn(static function ($test): void {
+		});
+
+		// Nothing to assert. No errors means everything is fine.
+		$this->addToAssertionCount(1);
+	}
+}
diff --git a/tests/lib/AppFramework/Utility/SimpleContainerTest.php b/tests/lib/AppFramework/Utility/SimpleContainerTest.php
index f8a43058305..36fa1febfcf 100644
--- a/tests/lib/AppFramework/Utility/SimpleContainerTest.php
+++ b/tests/lib/AppFramework/Utility/SimpleContainerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * ownCloud - App Framework
  *
@@ -67,13 +69,14 @@ class SimpleContainerTest extends \Test\TestCase {
 	}
 
 
+
 	public function testRegister() {
 		$this->container->registerParameter('test', 'abc');
 		$this->assertEquals('abc', $this->container->query('test'));
 	}
 
 
-	
+
 	public function testNothingRegistered() {
 		$this->expectException(\OCP\AppFramework\QueryException::class);
 
@@ -81,7 +84,7 @@ class SimpleContainerTest extends \Test\TestCase {
 	}
 
 
-	
+
 	public function testNotAClass() {
 		$this->expectException(\OCP\AppFramework\QueryException::class);
 
@@ -190,7 +193,7 @@ class SimpleContainerTest extends \Test\TestCase {
 		$this->assertEquals('abc', $this->container->query($query));
 	}
 
-	
+
 	public function testConstructorComplexNoTestParameterFound() {
 		$this->expectException(\OCP\AppFramework\QueryException::class);