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    <h3>Editing: PutenvAdapter.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

declare(strict_types=1);

namespace Dotenv\Repository\Adapter;

use PhpOption\None;
use PhpOption\Option;
use PhpOption\Some;

final class PutenvAdapter implements AdapterInterface
{
    /**
     * Create a new putenv adapter instance.
     *
     * @return void
     */
    private function __construct()
    {
        //
    }

    /**
     * Create a new instance of the adapter, if it is available.
     *
     * @return \PhpOption\Option&lt;\Dotenv\Repository\Adapter\AdapterInterface&gt;
     */
    public static function create()
    {
        if (self::isSupported()) {
            /** @var \PhpOption\Option&lt;AdapterInterface&gt; */
            return Some::create(new self());
        }

        return None::create();
    }

    /**
     * Determines if the adapter is supported.
     *
     * @return bool
     */
    private static function isSupported()
    {
        return \function_exists('getenv') &amp;&amp; \function_exists('putenv');
    }

    /**
     * Read an environment variable, if it exists.
     *
     * @param non-empty-string $name
     *
     * @return \PhpOption\Option&lt;string&gt;
     */
    public function read(string $name)
    {
        /** @var \PhpOption\Option&lt;string&gt; */
        return Option::fromValue(\getenv($name), false)-&gt;filter(static function ($value) {
            return \is_string($value);
        });
    }

    /**
     * Write to an environment variable, if possible.
     *
     * @param non-empty-string $name
     * @param string           $value
     *
     * @return bool
     */
    public function write(string $name, string $value)
    {
        \putenv(&quot;$name=$value&quot;);

        return true;
    }

    /**
     * Delete an environment variable, if possible.
     *
     * @param non-empty-string $name
     *
     * @return bool
     */
    public function delete(string $name)
    {
        \putenv($name);

        return true;
    }
}
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