From 008a7af094876a8bb1710d8a7503a486b6c1ce3b Mon Sep 17 00:00:00 2001
From: Oliver Hader <oliver@typo3.org>
Date: Tue, 14 Mar 2023 22:11:55 +0100
Subject: [PATCH] [TASK] Introduce Map data-structure
Unfortunately PHP emphasizes "weak" over "map" in their new PHP 8
data-structure `\WeakMap`. As a result it cannot be passed to other
functions that would enrich an existing `\WeakMap` - since objects
created in that function scope would not exist outside and thus
directly trigger garbage collection of `\WeakMap`.
`\SplObjectStorage` has a strange behavior when using an iteration
like `foreach ($map as $key => $value)` - the `$value` is actually
the `$key` for BC reasons.
As a substitute, `\TYPO3\CMS\Core\Type\Map` is introduced which has a
similar behavior and got an additional `Map::fromEntries()` factory.
It acts as a wrapper of `\SplObjectStorage` with reduced features.
Example:
$map = new \TYPO3\CMS\Core\Type\Map();
$key = new \stdClass();
$value = new \stdClass();
$map[$key] = $value;
foreach ($map as $key => $value) { ... }
Resolves: #100168
Releases: main
Change-Id: I5c26dc4aa9b4679112a27bd4cbebcfbe0899b094
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78127
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
---
typo3/sysext/core/Classes/Type/Map.php | 117 ++++++++++++++++++
typo3/sysext/core/Tests/Unit/Type/MapTest.php | 110 ++++++++++++++++
2 files changed, 227 insertions(+)
create mode 100644 typo3/sysext/core/Classes/Type/Map.php
create mode 100644 typo3/sysext/core/Tests/Unit/Type/MapTest.php
diff --git a/typo3/sysext/core/Classes/Type/Map.php b/typo3/sysext/core/Classes/Type/Map.php
new file mode 100644
index 000000000000..f605ba26fcaa
--- /dev/null
+++ b/typo3/sysext/core/Classes/Type/Map.php
@@ -0,0 +1,117 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+namespace TYPO3\CMS\Core\Type;
+
+/**
+ * Map implementation that supports objects as keys.
+ *
+ * PHP's \WeakMap is not an option in case object keys are created and assigned
+ * in an encapsulated scope (like passing a map to a function to enrich it). In
+ * case the original object is not referenced anymore, it also will vanish from
+ * a \WeakMap, when used as key (see https://www.php.net/manual/class.weakmap.php).
+ *
+ * PHP's \SplObjectStorage has a strange behavior when using an iteration like
+ * `foreach ($map as $key => $value)` - the `$value` is actually the `$key` for
+ * BC reasons (see https://bugs.php.net/bug.php?id=49967).
+ *
+ * This individual implementation works around the "weak" behavior of \WeakMap
+ * and the iteration issue with `foreach` of `\SplObjectStorage` by acting as
+ * a wrapper for `\SplObjectStorage` with reduced features.
+ *
+ * Example:
+ * ```
+ * $map = new \TYPO3\CMS\Core\Type\Map();
+ * $key = new \stdClass();
+ * $value = new \stdClass();
+ * $map[$key] = $value;
+ *
+ * foreach ($map as $key => $value) { ... }
+ * ```
+ */
+final class Map implements \ArrayAccess, \Countable, \Iterator
+{
+ private \SplObjectStorage $storage;
+
+ /**
+ * @template E array{0:mixed, 1:mixed}
+ * @param list<E> $entries
+ */
+ public static function fromEntries(array ...$entries): self
+ {
+ $map = new self();
+ foreach ($entries as $entry) {
+ $map[$entry[0]] = $entry[1];
+ }
+ return $map;
+ }
+
+ public function __construct()
+ {
+ $this->storage = new \SplObjectStorage();
+ }
+
+ public function key(): mixed
+ {
+ return $this->storage->current();
+ }
+
+ public function current(): mixed
+ {
+ return $this->storage->getInfo();
+ }
+
+ public function next(): void
+ {
+ $this->storage->next();
+ }
+
+ public function rewind(): void
+ {
+ $this->storage->rewind();
+ }
+
+ public function valid(): bool
+ {
+ return $this->storage->valid();
+ }
+
+ public function offsetExists(mixed $offset): bool
+ {
+ return $this->storage->offsetExists($offset);
+ }
+
+ public function offsetGet(mixed $offset): mixed
+ {
+ return $this->storage->offsetGet($offset);
+ }
+
+ public function offsetSet(mixed $offset, mixed $value): void
+ {
+ $this->storage->offsetSet($offset, $value);
+ }
+
+ public function offsetUnset(mixed $offset): void
+ {
+ $this->storage->offsetUnset($offset);
+ }
+
+ public function count(): int
+ {
+ return count($this->storage);
+ }
+}
diff --git a/typo3/sysext/core/Tests/Unit/Type/MapTest.php b/typo3/sysext/core/Tests/Unit/Type/MapTest.php
new file mode 100644
index 000000000000..83aaa9cde76c
--- /dev/null
+++ b/typo3/sysext/core/Tests/Unit/Type/MapTest.php
@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+namespace TYPO3\CMS\Core\Tests\Unit\Type;
+
+use TYPO3\CMS\Core\Type\Map;
+use TYPO3\TestingFramework\Core\Unit\UnitTestCase;
+
+class MapTest extends UnitTestCase
+{
+ /**
+ * @test
+ */
+ public function mapIsArrayAccessible(): void
+ {
+ $aKey = new \stdClass();
+ $aValue = new \stdClass();
+ $bKey = new \stdClass();
+ $bValue = new \stdClass();
+
+ $map = new Map();
+ $map[$aKey] = $aValue;
+ $map[$bKey] = $bValue;
+
+ self::assertInstanceOf(Map::class, $map);
+ self::assertCount(2, $map);
+ self::assertSame($aValue, $map[$aKey]);
+ self::assertSame($bValue, $map[$bKey]);
+ }
+
+ /**
+ * @test
+ */
+ public function mapKeyCanBeUnset(): void
+ {
+ $aKey = new \stdClass();
+ $aValue = new \stdClass();
+ $bKey = new \stdClass();
+ $bValue = new \stdClass();
+
+ $map = new Map();
+ $map[$aKey] = $aValue;
+ $map[$bKey] = $bValue;
+
+ unset($map[$bKey]);
+
+ self::assertCount(1, $map);
+ self::assertFalse(isset($map[$bKey]));
+ }
+
+ /**
+ * @test
+ */
+ public function mapCanBeIterated(): void
+ {
+ $aKey = new \stdClass();
+ $aValue = new \stdClass();
+ $bKey = new \stdClass();
+ $bValue = new \stdClass();
+
+ $map = new Map();
+ $map[$aKey] = $aValue;
+ $map[$bKey] = $bValue;
+
+ $entries = [];
+ foreach ($map as $key => $value) {
+ $entries[] = [$key, $value];
+ }
+
+ $expectation = [
+ [$aKey, $aValue],
+ [$bKey, $bValue],
+ ];
+ self::assertSame($expectation, $entries);
+ }
+
+ /**
+ * @test
+ */
+ public function mapIsCreatedFromEntries(): void
+ {
+ $aKey = new \stdClass();
+ $aValue = new \stdClass();
+ $bKey = new \stdClass();
+ $bValue = new \stdClass();
+
+ $map = Map::fromEntries(
+ [$aKey, $aValue],
+ [$bKey, $bValue],
+ );
+
+ self::assertCount(2, $map);
+ self::assertSame($aValue, $map[$aKey]);
+ self::assertSame($bValue, $map[$bKey]);
+ }
+}
--
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