PHPLIB-1184: Improve CallbackIterator

src/Model/CallbackIterator.php

@@ -17,44 +17,54 @@
 
 namespace MongoDB\Model;
 
-use Closure;
 use Iterator;
 use IteratorIterator;
 use ReturnTypeWillChange;
 use Traversable;
 
+use function call_user_func;
+
 /**
  * Iterator to apply a callback before returning an element
  *
  * @internal
+ *
+ * @template TKey
+ * @template TValue
+ * @template TCallbackValue
+ * @template-implements Iterator<TKey, TCallbackValue>
  */
 class CallbackIterator implements Iterator
 {
- /** @var Closure */
- private $callback;
+ /** @var callable(TValue, TKey): TCallbackValue */
+ private $callable;
 
- /** @var Iterator */
+ /** @var Iterator<TKey, TValue> */
  private $iterator;
 
- public function __construct(Traversable $traversable, Closure $callback)
+ /**
+ * @param Traversable<TKey, TValue> $traversable
+ * @param callable(TValue, TKey): TCallbackValue $callable
+ */
+ public function __construct(Traversable $traversable, callable $callable)
  {
  $this->iterator = $traversable instanceof Iterator ? $traversable : new IteratorIterator($traversable);
- $this->callback = $callback;
+ $this->callable = $callable;
  }
 
  /**
  * @see https://php.net/iterator.current
- * @return mixed
+ * @return TCallbackValue
  */
  #[ReturnTypeWillChange]
  public function current()
  {
- return ($this->callback)($this->iterator->current());
+ return call_user_func($this->callable, $this->iterator->current(), $this->iterator->key());
  }
 
  /**
  * @see https://php.net/iterator.key
- * @return mixed
+ * @return TKey
  */
  #[ReturnTypeWillChange]
  public function key()

tests/Model/CallbackIteratorTest.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace MongoDB\Tests\Model;
+
+use ArrayIterator;
+use MongoDB\Model\CallbackIterator;
+use MongoDB\Tests\TestCase;
+
+use function array_keys;
+use function iterator_to_array;
+use function strrev;
+
+class CallbackIteratorTest extends TestCase
+{
+ public function testArrayIteration(): void
+ {
+ $expectedKey = 0;
+
+ $original = [1, 2, 3];
+
+ $callbackIterator = new CallbackIterator(
+ new ArrayIterator($original),
+ function ($value, $key) use (&$expectedKey) {
+ $this->assertSame($expectedKey, $key);
+ $expectedKey++;
+
+ return $value * 2;
+ }
+ );
+
+ $this->assertSame([2, 4, 6], iterator_to_array($callbackIterator));
+ }
+
+ public function testHashIteration(): void
+ {
+ $expectedKey = 0;
+
+ $original = ['a' => 1, 'b' => 2, 'c' => 3];
+ $expectedKeys = array_keys($original);
+
+ $callbackIterator = new CallbackIterator(
+ new ArrayIterator($original),
+ function ($value, $key) use (&$expectedKey, $expectedKeys) {
+ $this->assertSame($expectedKeys[$expectedKey], $key);
+ $expectedKey++;
+
+ return $value * 2;
+ }
+ );
+
+ $this->assertSame(['a' => 2, 'b' => 4, 'c' => 6], iterator_to_array($callbackIterator));
+ }
+
+ public function testWithCallable(): void
+ {
+ $original = ['foo', 'bar', 'baz'];
+
+ $callbackIterator = new CallbackIterator(
+ new ArrayIterator($original),
+ [self::class, 'reverseValue']
+ );
+
+ $this->assertSame(['oof', 'rab', 'zab'], iterator_to_array($callbackIterator));
+ }
+
+ public static function reverseValue($value, $key)
+ {
+ return strrev($value);
+ }
+}