✨ Implement ObjectProxy class

src/Example.php

@@ -1,37 +0,0 @@
-<?php
-
-/**
- * This file is part of danjones000/object-spy
- *
- * danjones000/object-spy is open source software: you can distribute
- * it and/or modify it under the terms of the MIT License
- * (the "License"). You may not use this file except in
- * compliance with the License.
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
- * implied. See the License for the specific language governing
- * permissions and limitations under the License.
- *
- * @copyright Copyright (c) Dan Jones <danjones@goodevilgenius.org>
- * @license https://opensource.org/licenses/MIT MIT License
- */
-
-declare(strict_types=1);
-
-namespace Danjones000\Spy;
-
-/**
- * An example class to act as a starting point for developing your library
- */
-class Example
-{
-    /**
-     * Returns a greeting statement using the provided name
-     */
-    public function greet(string $name = 'World'): string
-    {
-        return "Hello, {$name}!";
-    }
-}

src/ObjectProxy.php

@@ -0,0 +1,157 @@
+<?php
+
+/**
+ * This file is part of danjones000/object-spy
+ *
+ * danjones000/object-spy is open source software: you can distribute
+ * it and/or modify it under the terms of the MIT License
+ * (the "License"). You may not use this file except in
+ * compliance with the License.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ *
+ * @copyright Copyright (c) Dan Jones <danjones@goodevilgenius.org>
+ * @license https://opensource.org/licenses/MIT MIT License
+ */
+
+declare(strict_types=1);
+
+namespace Danjones000\Spy;
+
+use Closure;
+use InvalidArgumentException;
+
+use function class_exists;
+use function get_class;
+use function is_null;
+use function is_object;
+use function is_string;
+
+/**
+ * Proxies all calls to another object/class, via Closures.
+ *
+ * This allows access to private/protected methods and properties without Reflection.
+ */
+class ObjectProxy
+{
+    protected ?string $class;
+    protected ?object $object;
+    protected Closure $caller;
+    protected Closure $getter;
+    protected Closure $setter;
+
+    /**
+     * @param string|object $classOrObject
+     *
+     * @psalm-suppress RedundantConditionGivenDocblockType
+     */
+    public function __construct($classOrObject)
+    {
+        [$this->object, $this->class] = is_object($classOrObject) ?
+                          [$classOrObject, get_class($classOrObject)] :
+                          (
+                              is_string($classOrObject) && class_exists($classOrObject) ?
+                              [null, $classOrObject] :
+                              [null, null]
+                          );
+        $this->assertValid();
+    }
+
+    protected function assertValid(): void
+    {
+        if (is_null($this->class)) {
+            throw new InvalidArgumentException('Must specify a class, or object');
+        }
+
+        if (!class_exists($this->class)) {
+            throw new InvalidArgumentException('Must specify a valid class');
+        }
+    }
+
+    /**
+     * Get the closure used by $this->__call.
+     *
+     * @psalm-suppress PossiblyNullArgument
+     */
+    protected function getCaller(): Closure
+    {
+        return $this->caller ??= (
+            $this->object ?
+            fn (string $method, array $args) => $this->$method(...$args) :
+            static fn (string $method, array $args) => static::$method(...$args)
+        )->bindTo($this->object, $this->class);
+    }
+
+    /**
+     * Get the closure used by $this->__get.
+     *
+     * @psalm-suppress PossiblyNullArgument
+     * @psalm-suppress UnusedClosureParam
+     */
+    protected function getGetter(): Closure
+    {
+        return $this->getter ??= (
+            $this->object ?
+            fn (string $key) => $this->$key :
+            static fn (string $key) => static::$$key
+        )->bindTo($this->object, $this->class);
+    }
+
+    /**
+     * Get the closure used by $this->__set.
+     *
+     * @psalm-suppress PossiblyNullArgument
+     * @psalm-suppress MixedAssignment
+     */
+    protected function getSetter(): Closure
+    {
+        return $this->setter ??= (
+            $this->object ?
+            fn (string $key, $value) => $this->$key = $value :
+            static fn (string $key, $value) => static::$$key = $value
+        )->bindTo($this->object, $this->class);
+    }
+
+    /**
+     * Run arbitry code on object, with access to private/protected props/methods.
+     *
+     * @param mixed[] $args
+     * @return mixed
+     * @psalm-suppress PossiblyNullArgument
+     * @psalm-suppress PossiblyInvalidFunctionCall
+     */
+    public function call(callable $cb, array ...$args)
+    {
+        return (Closure::fromCallable($cb)->bindTo($this->object, $this->class))(...$args);
+    }
+
+    /**
+     * @param mixed[] $args
+     * @return mixed
+     */
+    public function __call(string $method, array $args)
+    {
+        return ($this->getCaller())($method, $args);
+    }
+
+    /**
+     * @return mixed
+     */
+    public function __get(string $key)
+    {
+        return ($this->getGetter())($key);
+    }
+
+    /**
+     * @param mixed $value
+     * @return mixed
+     */
+    public function __set(string $key, $value)
+    {
+        return ($this->getSetter())($key, $value);
+    }
+}