<form method="POST">
    <h3>Editing: CodeUnit.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);
/*
 * This file is part of sebastian/code-unit.
 *
 * (c) Sebastian Bergmann &lt;sebastian@phpunit.de&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace SebastianBergmann\CodeUnit;

use function range;
use function sprintf;
use ReflectionClass;
use ReflectionFunction;
use ReflectionMethod;

/**
 * @psalm-immutable
 */
abstract class CodeUnit
{
    /**
     * @var string
     */
    private $name;

    /**
     * @var string
     */
    private $sourceFileName;

    /**
     * @var array
     * @psalm-var list&lt;int&gt;
     */
    private $sourceLines;

    /**
     * @psalm-param class-string $className
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forClass(string $className): ClassUnit
    {
        self::ensureUserDefinedClass($className);

        $reflector = self::reflectorForClass($className);

        return new ClassUnit(
            $className,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param class-string $className
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forClassMethod(string $className, string $methodName): ClassMethodUnit
    {
        self::ensureUserDefinedClass($className);

        $reflector = self::reflectorForClassMethod($className, $methodName);

        return new ClassMethodUnit(
            $className . '::' . $methodName,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param class-string $interfaceName
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forInterface(string $interfaceName): InterfaceUnit
    {
        self::ensureUserDefinedInterface($interfaceName);

        $reflector = self::reflectorForClass($interfaceName);

        return new InterfaceUnit(
            $interfaceName,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param class-string $interfaceName
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forInterfaceMethod(string $interfaceName, string $methodName): InterfaceMethodUnit
    {
        self::ensureUserDefinedInterface($interfaceName);

        $reflector = self::reflectorForClassMethod($interfaceName, $methodName);

        return new InterfaceMethodUnit(
            $interfaceName . '::' . $methodName,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param class-string $traitName
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forTrait(string $traitName): TraitUnit
    {
        self::ensureUserDefinedTrait($traitName);

        $reflector = self::reflectorForClass($traitName);

        return new TraitUnit(
            $traitName,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param class-string $traitName
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forTraitMethod(string $traitName, string $methodName): TraitMethodUnit
    {
        self::ensureUserDefinedTrait($traitName);

        $reflector = self::reflectorForClassMethod($traitName, $methodName);

        return new TraitMethodUnit(
            $traitName . '::' . $methodName,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param callable-string $functionName
     *
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public static function forFunction(string $functionName): FunctionUnit
    {
        $reflector = self::reflectorForFunction($functionName);

        if (!$reflector-&gt;isUserDefined()) {
            throw new InvalidCodeUnitException(
                sprintf(
                    '&quot;%s&quot; is not a user-defined function',
                    $functionName
                )
            );
        }

        return new FunctionUnit(
            $functionName,
            $reflector-&gt;getFileName(),
            range(
                $reflector-&gt;getStartLine(),
                $reflector-&gt;getEndLine()
            )
        );
    }

    /**
     * @psalm-param list&lt;int&gt; $sourceLines
     */
    private function __construct(string $name, string $sourceFileName, array $sourceLines)
    {
        $this-&gt;name           = $name;
        $this-&gt;sourceFileName = $sourceFileName;
        $this-&gt;sourceLines    = $sourceLines;
    }

    public function name(): string
    {
        return $this-&gt;name;
    }

    public function sourceFileName(): string
    {
        return $this-&gt;sourceFileName;
    }

    /**
     * @psalm-return list&lt;int&gt;
     */
    public function sourceLines(): array
    {
        return $this-&gt;sourceLines;
    }

    public function isClass(): bool
    {
        return false;
    }

    public function isClassMethod(): bool
    {
        return false;
    }

    public function isInterface(): bool
    {
        return false;
    }

    public function isInterfaceMethod(): bool
    {
        return false;
    }

    public function isTrait(): bool
    {
        return false;
    }

    public function isTraitMethod(): bool
    {
        return false;
    }

    public function isFunction(): bool
    {
        return false;
    }

    /**
     * @psalm-param class-string $className
     *
     * @throws InvalidCodeUnitException
     */
    private static function ensureUserDefinedClass(string $className): void
    {
        try {
            $reflector = new ReflectionClass($className);

            if ($reflector-&gt;isInterface()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is an interface and not a class',
                        $className
                    )
                );
            }

            if ($reflector-&gt;isTrait()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is a trait and not a class',
                        $className
                    )
                );
            }

            if (!$reflector-&gt;isUserDefined()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is not a user-defined class',
                        $className
                    )
                );
            }
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException(
                $e-&gt;getMessage(),
                (int) $e-&gt;getCode(),
                $e
            );
        }
        // @codeCoverageIgnoreEnd
    }

    /**
     * @psalm-param class-string $interfaceName
     *
     * @throws InvalidCodeUnitException
     */
    private static function ensureUserDefinedInterface(string $interfaceName): void
    {
        try {
            $reflector = new ReflectionClass($interfaceName);

            if (!$reflector-&gt;isInterface()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is not an interface',
                        $interfaceName
                    )
                );
            }

            if (!$reflector-&gt;isUserDefined()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is not a user-defined interface',
                        $interfaceName
                    )
                );
            }
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException(
                $e-&gt;getMessage(),
                (int) $e-&gt;getCode(),
                $e
            );
        }
        // @codeCoverageIgnoreEnd
    }

    /**
     * @psalm-param class-string $traitName
     *
     * @throws InvalidCodeUnitException
     */
    private static function ensureUserDefinedTrait(string $traitName): void
    {
        try {
            $reflector = new ReflectionClass($traitName);

            if (!$reflector-&gt;isTrait()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is not a trait',
                        $traitName
                    )
                );
            }

            // @codeCoverageIgnoreStart
            if (!$reflector-&gt;isUserDefined()) {
                throw new InvalidCodeUnitException(
                    sprintf(
                        '&quot;%s&quot; is not a user-defined trait',
                        $traitName
                    )
                );
            }
        } catch (\ReflectionException $e) {
            throw new ReflectionException(
                $e-&gt;getMessage(),
                (int) $e-&gt;getCode(),
                $e
            );
        }
        // @codeCoverageIgnoreEnd
    }

    /**
     * @psalm-param class-string $className
     *
     * @throws ReflectionException
     */
    private static function reflectorForClass(string $className): ReflectionClass
    {
        try {
            return new ReflectionClass($className);
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException(
                $e-&gt;getMessage(),
                (int) $e-&gt;getCode(),
                $e
            );
        }
        // @codeCoverageIgnoreEnd
    }

    /**
     * @psalm-param class-string $className
     *
     * @throws ReflectionException
     */
    private static function reflectorForClassMethod(string $className, string $methodName): ReflectionMethod
    {
        try {
            return new ReflectionMethod($className, $methodName);
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException(
                $e-&gt;getMessage(),
                (int) $e-&gt;getCode(),
                $e
            );
        }
        // @codeCoverageIgnoreEnd
    }

    /**
     * @psalm-param callable-string $functionName
     *
     * @throws ReflectionException
     */
    private static function reflectorForFunction(string $functionName): ReflectionFunction
    {
        try {
            return new ReflectionFunction($functionName);
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException(
                $e-&gt;getMessage(),
                (int) $e-&gt;getCode(),
                $e
            );
        }
        // @codeCoverageIgnoreEnd
    }
}
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