<?php
declare(strict_types=1);
namespace Dotenv\Repository\Adapter;
final class ImmutableWriter implements WriterInterface
{
/**
* The inner writer to use.
*
* @var \Dotenv\Repository\Adapter\WriterInterface
*/
private $writer;
/**
* The inner reader to use.
*
* @var \Dotenv\Repository\Adapter\ReaderInterface
*/
private $reader;
/**
* The record of loaded variables.
*
* @var array<string,string>
*/
private $loaded;
/**
* Create a new immutable writer instance.
*
* @param \Dotenv\Repository\Adapter\WriterInterface $writer
* @param \Dotenv\Repository\Adapter\ReaderInterface $reader
*
* @return void
*/
public function __construct(WriterInterface $writer, ReaderInterface $reader)
{
$this->writer = $writer;
$this->reader = $reader;
$this->loaded = [];
}
/**
* Write to an environment variable, if possible.
*
* @param non-empty-string $name
* @param string $value
*
* @return bool
*/
public function write(string $name, string $value)
{
// Don't overwrite existing environment variables
// Ruby's dotenv does this with `ENV[key] ||= value`
if ($this->isExternallyDefined($name)) {
return false;
}
// Set the value on the inner writer
if (!$this->writer->write($name, $value)) {
return false;
}
// Record that we have loaded the variable
$this->loaded[$name] = '';
return true;
}
/**
* Delete an environment variable, if possible.
*
* @param non-empty-string $name
*
* @return bool
*/
public function delete(string $name)
{
// Don't clear existing environment variables
if ($this->isExternallyDefined($name)) {
return false;
}
// Clear the value on the inner writer
if (!$this->writer->delete($name)) {
return false;
}
// Leave the variable as fair game
unset($this->loaded[$name]);
return true;
}
/**
* Determine if the given variable is externally defined.
*
* That is, is it an "existing" variable.
*
* @param non-empty-string $name
*
* @return bool
*/
private function isExternallyDefined(string $name)
{
return $this->reader->read($name)->isDefined() && !isset($this->loaded[$name]);
}
}