Enhancement: Implement JsonPointer

CHANGELOG.md

@@ -6,14 +6,21 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## Unreleased
 
-For a full diff see [`a5ba52c...main`][a5ba52c...main].
+For a full diff see [`1.0.0...main`][1.0.0...main].
+
+## [`1.0.0`][1.0.0]
+
+For a full diff see [`a5ba52c...1.0.0`][a5ba52c...1.0.0].
 
 ### Added
 
 - Added `ReferenceToken` as a value object ([#1]), by [@localheinz]
+- Added `JsonPointer` as a value object ([#2]), by [@localheinz]
 
-[a5ba52c...main]: https://github.com/ergebnis/json-pointer/compare/a5ba52c...main
+[a5ba52c...1.0.0]: https://github.com/ergebnis/json-pointer/compare/a5ba52c...1.0.0
+[1.0.0...main]: https://github.com/ergebnis/json-pointer/compare/1.0.0...main
 
 [#1]: https://github.com/ergebnis/json-pointer/pull/1
+[#2]: https://github.com/ergebnis/json-pointer/pull/2
 
 [@localheinz]: https://github.com/localheinz

README.md

@@ -85,6 +85,69 @@ $two = Pointer\ReferenceToken::fromEscapedString('foo~1bar');
 $one->equals($two); // true
 ```
 
+### `JsonPointer`
+
+You can create a `JsonPointer` referencing a document:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+use Ergebnis\Json\Pointer;
+
+$jsonPointer = Pointer\JsonPointer::document();
+
+$jsonPointer->toString(); // ''
+```
+
+You can create a `JsonPointer` from a `string` value:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+use Ergebnis\Json\Pointer;
+
+$jsonPointer = Pointer\JsonPointer::fromString('/foo/bar');
+
+$jsonPointer->toString(); // '/foo/bar'
+```
+
+You can compare `JsonPointer`s:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+use Ergebnis\Json\Pointer;
+
+$one = Pointer\JsonPointer::fromString('/foo/bar');
+$two = Pointer\JsonPointer::fromString('/foo~1bar');
+
+$one->equals($two); // false
+```
+
+You can append a `ReferenceToken` to a `JsonPointer`:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+use Ergebnis\Json\Pointer;
+
+$jsonPointer = Pointer\JsonPointer::fromString('/foo/bar');
+
+$referenceToken = Pointer\ReferenceToken::fromUnescapedString('baz');
+
+$newJsonPointer = $jsonPointer->append($referenceToken);
+
+$newJsonPointer->toString(); // '/foo/bar/baz'
+```
+
 ## Changelog
 
 Please have a look at [`CHANGELOG.md`](CHANGELOG.md).

src/Exception/InvalidJsonPointer.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2020-2022 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/json-pointer
+ */
+
+namespace Ergebnis\Json\Pointer\Exception;
+
+final class InvalidJsonPointer extends \InvalidArgumentException implements Exception
+{
+    public static function fromString(string $value): self
+    {
+        return new self(\sprintf(
+            'Value "%s" does not appear to be a valid JSON Pointer.',
+            $value,
+        ));
+    }
+}

src/JsonPointer.php

@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2020-2022 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/json-pointer
+ */
+
+namespace Ergebnis\Json\Pointer;
+
+/**
+ * @psalm-immutable
+ *
+ * @see https://datatracker.ietf.org/doc/html/rfc6901
+ */
+final class JsonPointer
+{
+    private string $value;
+
+    private function __construct(string $value)
+    {
+        $this->value = $value;
+    }
+
+    /**
+     * @see https://datatracker.ietf.org/doc/html/rfc6901#section-3
+     *
+     * @throws Exception\InvalidJsonPointer
+     */
+    public static function fromString(string $value): self
+    {
+        if (1 !== \preg_match('/^(\/(?P<referenceToken>((?P<unescaped>[\x00-\x2E]|[\x30-\x7D]|[\x7F-\x{10FFFF}])|(?P<escaped>~[01]))*))*$/u', $value, $matches)) {
+            throw Exception\InvalidJsonPointer::fromString($value);
+        }
+
+        return new self($value);
+    }
+
+    public static function document(): self
+    {
+        return new self('');
+    }
+
+    public function append(ReferenceToken $referenceToken): self
+    {
+        return new self(\sprintf(
+            '%s/%s',
+            $this->value,
+            $referenceToken->toEscapedString(),
+        ));
+    }
+
+    public function toString(): string
+    {
+        return $this->value;
+    }
+
+    public function equals(self $other): bool
+    {
+        return $this->value === $other->value;
+    }
+}

test/Unit/Exception/InvalidJsonPointerTest.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2020-2022 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/json-pointer
+ */
+
+namespace Ergebnis\Json\Pointer\Test\Unit\Exception;
+
+use Ergebnis\Json\Pointer\Exception;
+use Ergebnis\Json\Pointer\Test;
+use PHPUnit\Framework;
+
+/**
+ * @internal
+ *
+ * @covers \Ergebnis\Json\Pointer\Exception\InvalidJsonPointer
+ */
+final class InvalidJsonPointerTest extends Framework\TestCase
+{
+    use Test\Util\Helper;
+
+    public function testFromValueReturnsInvalidJsonPointerException(): void
+    {
+        $value = self::faker()->sentence();
+
+        $exception = Exception\InvalidJsonPointer::fromString($value);
+
+        $message = \sprintf(
+            'Value "%s" does not appear to be a valid JSON Pointer.',
+            $value,
+        );
+
+        self::assertSame($message, $exception->getMessage());
+    }
+}