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

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Process;

use Symfony\Component\Process\Exception\InvalidArgumentException;
use Symfony\Component\Process\Exception\LogicException;
use Symfony\Component\Process\Exception\ProcessFailedException;
use Symfony\Component\Process\Exception\ProcessSignaledException;
use Symfony\Component\Process\Exception\ProcessTimedOutException;
use Symfony\Component\Process\Exception\RuntimeException;
use Symfony\Component\Process\Pipes\PipesInterface;
use Symfony\Component\Process\Pipes\UnixPipes;
use Symfony\Component\Process\Pipes\WindowsPipes;

/**
 * Process is a thin wrapper around proc_* functions to easily
 * start independent PHP processes.
 *
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 * @author Romain Neutron &lt;imprec@gmail.com&gt;
 *
 * @implements \IteratorAggregate&lt;string, string&gt;
 */
class Process implements \IteratorAggregate
{
    public const ERR = 'err';
    public const OUT = 'out';

    public const STATUS_READY = 'ready';
    public const STATUS_STARTED = 'started';
    public const STATUS_TERMINATED = 'terminated';

    public const STDIN = 0;
    public const STDOUT = 1;
    public const STDERR = 2;

    // Timeout Precision in seconds.
    public const TIMEOUT_PRECISION = 0.2;

    public const ITER_NON_BLOCKING = 1; // By default, iterating over outputs is a blocking call, use this flag to make it non-blocking
    public const ITER_KEEP_OUTPUT = 2;  // By default, outputs are cleared while iterating, use this flag to keep them in memory
    public const ITER_SKIP_OUT = 4;     // Use this flag to skip STDOUT while iterating
    public const ITER_SKIP_ERR = 8;     // Use this flag to skip STDERR while iterating

    private $callback;
    private $hasCallback = false;
    private $commandline;
    private $cwd;
    private $env = [];
    private $input;
    private $starttime;
    private $lastOutputTime;
    private $timeout;
    private $idleTimeout;
    private $exitcode;
    private $fallbackStatus = [];
    private $processInformation;
    private $outputDisabled = false;
    private $stdout;
    private $stderr;
    private $process;
    private $status = self::STATUS_READY;
    private $incrementalOutputOffset = 0;
    private $incrementalErrorOutputOffset = 0;
    private $tty = false;
    private $pty;
    private $options = ['suppress_errors' =&gt; true, 'bypass_shell' =&gt; true];

    private $useFileHandles = false;
    /** @var PipesInterface */
    private $processPipes;

    private $latestSignal;

    private static $sigchild;

    /**
     * Exit codes translation table.
     *
     * User-defined errors must use exit codes in the 64-113 range.
     */
    public static $exitCodes = [
        0 =&gt; 'OK',
        1 =&gt; 'General error',
        2 =&gt; 'Misuse of shell builtins',

        126 =&gt; 'Invoked command cannot execute',
        127 =&gt; 'Command not found',
        128 =&gt; 'Invalid exit argument',

        // signals
        129 =&gt; 'Hangup',
        130 =&gt; 'Interrupt',
        131 =&gt; 'Quit and dump core',
        132 =&gt; 'Illegal instruction',
        133 =&gt; 'Trace/breakpoint trap',
        134 =&gt; 'Process aborted',
        135 =&gt; 'Bus error: &quot;access to undefined portion of memory object&quot;',
        136 =&gt; 'Floating point exception: &quot;erroneous arithmetic operation&quot;',
        137 =&gt; 'Kill (terminate immediately)',
        138 =&gt; 'User-defined 1',
        139 =&gt; 'Segmentation violation',
        140 =&gt; 'User-defined 2',
        141 =&gt; 'Write to pipe with no one reading',
        142 =&gt; 'Signal raised by alarm',
        143 =&gt; 'Termination (request to terminate)',
        // 144 - not defined
        145 =&gt; 'Child process terminated, stopped (or continued*)',
        146 =&gt; 'Continue if stopped',
        147 =&gt; 'Stop executing temporarily',
        148 =&gt; 'Terminal stop signal',
        149 =&gt; 'Background process attempting to read from tty (&quot;in&quot;)',
        150 =&gt; 'Background process attempting to write to tty (&quot;out&quot;)',
        151 =&gt; 'Urgent data available on socket',
        152 =&gt; 'CPU time limit exceeded',
        153 =&gt; 'File size limit exceeded',
        154 =&gt; 'Signal raised by timer counting virtual time: &quot;virtual timer expired&quot;',
        155 =&gt; 'Profiling timer expired',
        // 156 - not defined
        157 =&gt; 'Pollable event',
        // 158 - not defined
        159 =&gt; 'Bad syscall',
    ];

    /**
     * @param array          $command The command to run and its arguments listed as separate entries
     * @param string|null    $cwd     The working directory or null to use the working dir of the current PHP process
     * @param array|null     $env     The environment variables or null to use the same environment as the current PHP process
     * @param mixed          $input   The input as stream resource, scalar or \Traversable, or null for no input
     * @param int|float|null $timeout The timeout in seconds or null to disable
     *
     * @throws LogicException When proc_open is not installed
     */
    public function __construct(array $command, string $cwd = null, array $env = null, mixed $input = null, ?float $timeout = 60)
    {
        if (!\function_exists('proc_open')) {
            throw new LogicException('The Process class relies on proc_open, which is not available on your PHP installation.');
        }

        $this-&gt;commandline = $command;
        $this-&gt;cwd = $cwd;

        // on Windows, if the cwd changed via chdir(), proc_open defaults to the dir where PHP was started
        // on Gnu/Linux, PHP builds with --enable-maintainer-zts are also affected
        // @see : https://bugs.php.net/51800
        // @see : https://bugs.php.net/50524
        if (null === $this-&gt;cwd &amp;&amp; (\defined('ZEND_THREAD_SAFE') || '\\' === \DIRECTORY_SEPARATOR)) {
            $this-&gt;cwd = getcwd();
        }
        if (null !== $env) {
            $this-&gt;setEnv($env);
        }

        $this-&gt;setInput($input);
        $this-&gt;setTimeout($timeout);
        $this-&gt;useFileHandles = '\\' === \DIRECTORY_SEPARATOR;
        $this-&gt;pty = false;
    }

    /**
     * Creates a Process instance as a command-line to be run in a shell wrapper.
     *
     * Command-lines are parsed by the shell of your OS (/bin/sh on Unix-like, cmd.exe on Windows.)
     * This allows using e.g. pipes or conditional execution. In this mode, signals are sent to the
     * shell wrapper and not to your commands.
     *
     * In order to inject dynamic values into command-lines, we strongly recommend using placeholders.
     * This will save escaping values, which is not portable nor secure anyway:
     *
     *   $process = Process::fromShellCommandline('my_command &quot;${:MY_VAR}&quot;');
     *   $process-&gt;run(null, ['MY_VAR' =&gt; $theValue]);
     *
     * @param string         $command The command line to pass to the shell of the OS
     * @param string|null    $cwd     The working directory or null to use the working dir of the current PHP process
     * @param array|null     $env     The environment variables or null to use the same environment as the current PHP process
     * @param mixed          $input   The input as stream resource, scalar or \Traversable, or null for no input
     * @param int|float|null $timeout The timeout in seconds or null to disable
     *
     * @throws LogicException When proc_open is not installed
     */
    public static function fromShellCommandline(string $command, string $cwd = null, array $env = null, mixed $input = null, ?float $timeout = 60): static
    {
        $process = new static([], $cwd, $env, $input, $timeout);
        $process-&gt;commandline = $command;

        return $process;
    }

    public function __sleep(): array
    {
        throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
    }

    public function __wakeup()
    {
        throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
    }

    public function __destruct()
    {
        if ($this-&gt;options['create_new_console'] ?? false) {
            $this-&gt;processPipes-&gt;close();
        } else {
            $this-&gt;stop(0);
        }
    }

    public function __clone()
    {
        $this-&gt;resetProcessData();
    }

    /**
     * Runs the process.
     *
     * The callback receives the type of output (out or err) and
     * some bytes from the output in real-time. It allows to have feedback
     * from the independent process during execution.
     *
     * The STDOUT and STDERR are also available after the process is finished
     * via the getOutput() and getErrorOutput() methods.
     *
     * @param callable|null $callback A PHP callback to run whenever there is some
     *                                output available on STDOUT or STDERR
     *
     * @return int The exit status code
     *
     * @throws RuntimeException         When process can't be launched
     * @throws RuntimeException         When process is already running
     * @throws ProcessTimedOutException When process timed out
     * @throws ProcessSignaledException When process stopped after receiving signal
     * @throws LogicException           In case a callback is provided and output has been disabled
     *
     * @final
     */
    public function run(callable $callback = null, array $env = []): int
    {
        $this-&gt;start($callback, $env);

        return $this-&gt;wait();
    }

    /**
     * Runs the process.
     *
     * This is identical to run() except that an exception is thrown if the process
     * exits with a non-zero exit code.
     *
     * @return $this
     *
     * @throws ProcessFailedException if the process didn't terminate successfully
     *
     * @final
     */
    public function mustRun(callable $callback = null, array $env = []): static
    {
        if (0 !== $this-&gt;run($callback, $env)) {
            throw new ProcessFailedException($this);
        }

        return $this;
    }

    /**
     * Starts the process and returns after writing the input to STDIN.
     *
     * This method blocks until all STDIN data is sent to the process then it
     * returns while the process runs in the background.
     *
     * The termination of the process can be awaited with wait().
     *
     * The callback receives the type of output (out or err) and some bytes from
     * the output in real-time while writing the standard input to the process.
     * It allows to have feedback from the independent process during execution.
     *
     * @param callable|null $callback A PHP callback to run whenever there is some
     *                                output available on STDOUT or STDERR
     *
     * @throws RuntimeException When process can't be launched
     * @throws RuntimeException When process is already running
     * @throws LogicException   In case a callback is provided and output has been disabled
     */
    public function start(callable $callback = null, array $env = [])
    {
        if ($this-&gt;isRunning()) {
            throw new RuntimeException('Process is already running.');
        }

        $this-&gt;resetProcessData();
        $this-&gt;starttime = $this-&gt;lastOutputTime = microtime(true);
        $this-&gt;callback = $this-&gt;buildCallback($callback);
        $this-&gt;hasCallback = null !== $callback;
        $descriptors = $this-&gt;getDescriptors();

        if ($this-&gt;env) {
            $env += '\\' === \DIRECTORY_SEPARATOR ? array_diff_ukey($this-&gt;env, $env, 'strcasecmp') : $this-&gt;env;
        }

        $env += '\\' === \DIRECTORY_SEPARATOR ? array_diff_ukey($this-&gt;getDefaultEnv(), $env, 'strcasecmp') : $this-&gt;getDefaultEnv();

        if (\is_array($commandline = $this-&gt;commandline)) {
            $commandline = implode(' ', array_map($this-&gt;escapeArgument(...), $commandline));

            if ('\\' !== \DIRECTORY_SEPARATOR) {
                // exec is mandatory to deal with sending a signal to the process
                $commandline = 'exec '.$commandline;
            }
        } else {
            $commandline = $this-&gt;replacePlaceholders($commandline, $env);
        }

        if ('\\' === \DIRECTORY_SEPARATOR) {
            $commandline = $this-&gt;prepareWindowsCommandLine($commandline, $env);
        } elseif (!$this-&gt;useFileHandles &amp;&amp; $this-&gt;isSigchildEnabled()) {
            // last exit code is output on the fourth pipe and caught to work around --enable-sigchild
            $descriptors[3] = ['pipe', 'w'];

            // See https://unix.stackexchange.com/questions/71205/background-process-pipe-input
            $commandline = '{ ('.$commandline.') &lt;&amp;3 3&lt;&amp;- 3&gt;/dev/null &amp; } 3&lt;&amp;0;';
            $commandline .= 'pid=$!; echo $pid &gt;&amp;3; wait $pid; code=$?; echo $code &gt;&amp;3; exit $code';

            // Workaround for the bug, when PTS functionality is enabled.
            // @see : https://bugs.php.net/69442
            $ptsWorkaround = fopen(__FILE__, 'r');
        }

        $envPairs = [];
        foreach ($env as $k =&gt; $v) {
            if (false !== $v &amp;&amp; false === \in_array($k, ['argc', 'argv', 'ARGC', 'ARGV'], true)) {
                $envPairs[] = $k.'='.$v;
            }
        }

        if (!is_dir($this-&gt;cwd)) {
            throw new RuntimeException(sprintf('The provided cwd &quot;%s&quot; does not exist.', $this-&gt;cwd));
        }

        $this-&gt;process = @proc_open($commandline, $descriptors, $this-&gt;processPipes-&gt;pipes, $this-&gt;cwd, $envPairs, $this-&gt;options);

        if (!\is_resource($this-&gt;process)) {
            throw new RuntimeException('Unable to launch a new process.');
        }
        $this-&gt;status = self::STATUS_STARTED;

        if (isset($descriptors[3])) {
            $this-&gt;fallbackStatus['pid'] = (int) fgets($this-&gt;processPipes-&gt;pipes[3]);
        }

        if ($this-&gt;tty) {
            return;
        }

        $this-&gt;updateStatus(false);
        $this-&gt;checkTimeout();
    }

    /**
     * Restarts the process.
     *
     * Be warned that the process is cloned before being started.
     *
     * @param callable|null $callback A PHP callback to run whenever there is some
     *                                output available on STDOUT or STDERR
     *
     * @throws RuntimeException When process can't be launched
     * @throws RuntimeException When process is already running
     *
     * @see start()
     *
     * @final
     */
    public function restart(callable $callback = null, array $env = []): static
    {
        if ($this-&gt;isRunning()) {
            throw new RuntimeException('Process is already running.');
        }

        $process = clone $this;
        $process-&gt;start($callback, $env);

        return $process;
    }

    /**
     * Waits for the process to terminate.
     *
     * The callback receives the type of output (out or err) and some bytes
     * from the output in real-time while writing the standard input to the process.
     * It allows to have feedback from the independent process during execution.
     *
     * @param callable|null $callback A valid PHP callback
     *
     * @return int The exitcode of the process
     *
     * @throws ProcessTimedOutException When process timed out
     * @throws ProcessSignaledException When process stopped after receiving signal
     * @throws LogicException           When process is not yet started
     */
    public function wait(callable $callback = null): int
    {
        $this-&gt;requireProcessIsStarted(__FUNCTION__);

        $this-&gt;updateStatus(false);

        if (null !== $callback) {
            if (!$this-&gt;processPipes-&gt;haveReadSupport()) {
                $this-&gt;stop(0);
                throw new LogicException('Pass the callback to the &quot;Process::start&quot; method or call enableOutput to use a callback with &quot;Process::wait&quot;.');
            }
            $this-&gt;callback = $this-&gt;buildCallback($callback);
        }

        do {
            $this-&gt;checkTimeout();
            $running = '\\' === \DIRECTORY_SEPARATOR ? $this-&gt;isRunning() : $this-&gt;processPipes-&gt;areOpen();
            $this-&gt;readPipes($running, '\\' !== \DIRECTORY_SEPARATOR || !$running);
        } while ($running);

        while ($this-&gt;isRunning()) {
            $this-&gt;checkTimeout();
            usleep(1000);
        }

        if ($this-&gt;processInformation['signaled'] &amp;&amp; $this-&gt;processInformation['termsig'] !== $this-&gt;latestSignal) {
            throw new ProcessSignaledException($this);
        }

        return $this-&gt;exitcode;
    }

    /**
     * Waits until the callback returns true.
     *
     * The callback receives the type of output (out or err) and some bytes
     * from the output in real-time while writing the standard input to the process.
     * It allows to have feedback from the independent process during execution.
     *
     * @throws RuntimeException         When process timed out
     * @throws LogicException           When process is not yet started
     * @throws ProcessTimedOutException In case the timeout was reached
     */
    public function waitUntil(callable $callback): bool
    {
        $this-&gt;requireProcessIsStarted(__FUNCTION__);
        $this-&gt;updateStatus(false);

        if (!$this-&gt;processPipes-&gt;haveReadSupport()) {
            $this-&gt;stop(0);
            throw new LogicException('Pass the callback to the &quot;Process::start&quot; method or call enableOutput to use a callback with &quot;Process::waitUntil&quot;.');
        }
        $callback = $this-&gt;buildCallback($callback);

        $ready = false;
        while (true) {
            $this-&gt;checkTimeout();
            $running = '\\' === \DIRECTORY_SEPARATOR ? $this-&gt;isRunning() : $this-&gt;processPipes-&gt;areOpen();
            $output = $this-&gt;processPipes-&gt;readAndWrite($running, '\\' !== \DIRECTORY_SEPARATOR || !$running);

            foreach ($output as $type =&gt; $data) {
                if (3 !== $type) {
                    $ready = $callback(self::STDOUT === $type ? self::OUT : self::ERR, $data) || $ready;
                } elseif (!isset($this-&gt;fallbackStatus['signaled'])) {
                    $this-&gt;fallbackStatus['exitcode'] = (int) $data;
                }
            }
            if ($ready) {
                return true;
            }
            if (!$running) {
                return false;
            }

            usleep(1000);
        }
    }

    /**
     * Returns the Pid (process identifier), if applicable.
     *
     * @return int|null The process id if running, null otherwise
     */
    public function getPid(): ?int
    {
        return $this-&gt;isRunning() ? $this-&gt;processInformation['pid'] : null;
    }

    /**
     * Sends a POSIX signal to the process.
     *
     * @param int $signal A valid POSIX signal (see https://php.net/pcntl.constants)
     *
     * @return $this
     *
     * @throws LogicException   In case the process is not running
     * @throws RuntimeException In case --enable-sigchild is activated and the process can't be killed
     * @throws RuntimeException In case of failure
     */
    public function signal(int $signal): static
    {
        $this-&gt;doSignal($signal, true);

        return $this;
    }

    /**
     * Disables fetching output and error output from the underlying process.
     *
     * @return $this
     *
     * @throws RuntimeException In case the process is already running
     * @throws LogicException   if an idle timeout is set
     */
    public function disableOutput(): static
    {
        if ($this-&gt;isRunning()) {
            throw new RuntimeException('Disabling output while the process is running is not possible.');
        }
        if (null !== $this-&gt;idleTimeout) {
            throw new LogicException('Output cannot be disabled while an idle timeout is set.');
        }

        $this-&gt;outputDisabled = true;

        return $this;
    }

    /**
     * Enables fetching output and error output from the underlying process.
     *
     * @return $this
     *
     * @throws RuntimeException In case the process is already running
     */
    public function enableOutput(): static
    {
        if ($this-&gt;isRunning()) {
            throw new RuntimeException('Enabling output while the process is running is not possible.');
        }

        $this-&gt;outputDisabled = false;

        return $this;
    }

    /**
     * Returns true in case the output is disabled, false otherwise.
     */
    public function isOutputDisabled(): bool
    {
        return $this-&gt;outputDisabled;
    }

    /**
     * Returns the current output of the process (STDOUT).
     *
     * @throws LogicException in case the output has been disabled
     * @throws LogicException In case the process is not started
     */
    public function getOutput(): string
    {
        $this-&gt;readPipesForOutput(__FUNCTION__);

        if (false === $ret = stream_get_contents($this-&gt;stdout, -1, 0)) {
            return '';
        }

        return $ret;
    }

    /**
     * Returns the output incrementally.
     *
     * In comparison with the getOutput method which always return the whole
     * output, this one returns the new output since the last call.
     *
     * @throws LogicException in case the output has been disabled
     * @throws LogicException In case the process is not started
     */
    public function getIncrementalOutput(): string
    {
        $this-&gt;readPipesForOutput(__FUNCTION__);

        $latest = stream_get_contents($this-&gt;stdout, -1, $this-&gt;incrementalOutputOffset);
        $this-&gt;incrementalOutputOffset = ftell($this-&gt;stdout);

        if (false === $latest) {
            return '';
        }

        return $latest;
    }

    /**
     * Returns an iterator to the output of the process, with the output type as keys (Process::OUT/ERR).
     *
     * @param int $flags A bit field of Process::ITER_* flags
     *
     * @throws LogicException in case the output has been disabled
     * @throws LogicException In case the process is not started
     */
    public function getIterator(int $flags = 0): \Generator
    {
        $this-&gt;readPipesForOutput(__FUNCTION__, false);

        $clearOutput = !(self::ITER_KEEP_OUTPUT &amp; $flags);
        $blocking = !(self::ITER_NON_BLOCKING &amp; $flags);
        $yieldOut = !(self::ITER_SKIP_OUT &amp; $flags);
        $yieldErr = !(self::ITER_SKIP_ERR &amp; $flags);

        while (null !== $this-&gt;callback || ($yieldOut &amp;&amp; !feof($this-&gt;stdout)) || ($yieldErr &amp;&amp; !feof($this-&gt;stderr))) {
            if ($yieldOut) {
                $out = stream_get_contents($this-&gt;stdout, -1, $this-&gt;incrementalOutputOffset);

                if (isset($out[0])) {
                    if ($clearOutput) {
                        $this-&gt;clearOutput();
                    } else {
                        $this-&gt;incrementalOutputOffset = ftell($this-&gt;stdout);
                    }

                    yield self::OUT =&gt; $out;
                }
            }

            if ($yieldErr) {
                $err = stream_get_contents($this-&gt;stderr, -1, $this-&gt;incrementalErrorOutputOffset);

                if (isset($err[0])) {
                    if ($clearOutput) {
                        $this-&gt;clearErrorOutput();
                    } else {
                        $this-&gt;incrementalErrorOutputOffset = ftell($this-&gt;stderr);
                    }

                    yield self::ERR =&gt; $err;
                }
            }

            if (!$blocking &amp;&amp; !isset($out[0]) &amp;&amp; !isset($err[0])) {
                yield self::OUT =&gt; '';
            }

            $this-&gt;checkTimeout();
            $this-&gt;readPipesForOutput(__FUNCTION__, $blocking);
        }
    }

    /**
     * Clears the process output.
     *
     * @return $this
     */
    public function clearOutput(): static
    {
        ftruncate($this-&gt;stdout, 0);
        fseek($this-&gt;stdout, 0);
        $this-&gt;incrementalOutputOffset = 0;

        return $this;
    }

    /**
     * Returns the current error output of the process (STDERR).
     *
     * @throws LogicException in case the output has been disabled
     * @throws LogicException In case the process is not started
     */
    public function getErrorOutput(): string
    {
        $this-&gt;readPipesForOutput(__FUNCTION__);

        if (false === $ret = stream_get_contents($this-&gt;stderr, -1, 0)) {
            return '';
        }

        return $ret;
    }

    /**
     * Returns the errorOutput incrementally.
     *
     * In comparison with the getErrorOutput method which always return the
     * whole error output, this one returns the new error output since the last
     * call.
     *
     * @throws LogicException in case the output has been disabled
     * @throws LogicException In case the process is not started
     */
    public function getIncrementalErrorOutput(): string
    {
        $this-&gt;readPipesForOutput(__FUNCTION__);

        $latest = stream_get_contents($this-&gt;stderr, -1, $this-&gt;incrementalErrorOutputOffset);
        $this-&gt;incrementalErrorOutputOffset = ftell($this-&gt;stderr);

        if (false === $latest) {
            return '';
        }

        return $latest;
    }

    /**
     * Clears the process output.
     *
     * @return $this
     */
    public function clearErrorOutput(): static
    {
        ftruncate($this-&gt;stderr, 0);
        fseek($this-&gt;stderr, 0);
        $this-&gt;incrementalErrorOutputOffset = 0;

        return $this;
    }

    /**
     * Returns the exit code returned by the process.
     *
     * @return int|null The exit status code, null if the Process is not terminated
     */
    public function getExitCode(): ?int
    {
        $this-&gt;updateStatus(false);

        return $this-&gt;exitcode;
    }

    /**
     * Returns a string representation for the exit code returned by the process.
     *
     * This method relies on the Unix exit code status standardization
     * and might not be relevant for other operating systems.
     *
     * @return string|null A string representation for the exit status code, null if the Process is not terminated
     *
     * @see http://tldp.org/LDP/abs/html/exitcodes.html
     * @see http://en.wikipedia.org/wiki/Unix_signal
     */
    public function getExitCodeText(): ?string
    {
        if (null === $exitcode = $this-&gt;getExitCode()) {
            return null;
        }

        return self::$exitCodes[$exitcode] ?? 'Unknown error';
    }

    /**
     * Checks if the process ended successfully.
     */
    public function isSuccessful(): bool
    {
        return 0 === $this-&gt;getExitCode();
    }

    /**
     * Returns true if the child process has been terminated by an uncaught signal.
     *
     * It always returns false on Windows.
     *
     * @throws LogicException In case the process is not terminated
     */
    public function hasBeenSignaled(): bool
    {
        $this-&gt;requireProcessIsTerminated(__FUNCTION__);

        return $this-&gt;processInformation['signaled'];
    }

    /**
     * Returns the number of the signal that caused the child process to terminate its execution.
     *
     * It is only meaningful if hasBeenSignaled() returns true.
     *
     * @throws RuntimeException In case --enable-sigchild is activated
     * @throws LogicException   In case the process is not terminated
     */
    public function getTermSignal(): int
    {
        $this-&gt;requireProcessIsTerminated(__FUNCTION__);

        if ($this-&gt;isSigchildEnabled() &amp;&amp; -1 === $this-&gt;processInformation['termsig']) {
            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. Term signal cannot be retrieved.');
        }

        return $this-&gt;processInformation['termsig'];
    }

    /**
     * Returns true if the child process has been stopped by a signal.
     *
     * It always returns false on Windows.
     *
     * @throws LogicException In case the process is not terminated
     */
    public function hasBeenStopped(): bool
    {
        $this-&gt;requireProcessIsTerminated(__FUNCTION__);

        return $this-&gt;processInformation['stopped'];
    }

    /**
     * Returns the number of the signal that caused the child process to stop its execution.
     *
     * It is only meaningful if hasBeenStopped() returns true.
     *
     * @throws LogicException In case the process is not terminated
     */
    public function getStopSignal(): int
    {
        $this-&gt;requireProcessIsTerminated(__FUNCTION__);

        return $this-&gt;processInformation['stopsig'];
    }

    /**
     * Checks if the process is currently running.
     */
    public function isRunning(): bool
    {
        if (self::STATUS_STARTED !== $this-&gt;status) {
            return false;
        }

        $this-&gt;updateStatus(false);

        return $this-&gt;processInformation['running'];
    }

    /**
     * Checks if the process has been started with no regard to the current state.
     */
    public function isStarted(): bool
    {
        return self::STATUS_READY != $this-&gt;status;
    }

    /**
     * Checks if the process is terminated.
     */
    public function isTerminated(): bool
    {
        $this-&gt;updateStatus(false);

        return self::STATUS_TERMINATED == $this-&gt;status;
    }

    /**
     * Gets the process status.
     *
     * The status is one of: ready, started, terminated.
     */
    public function getStatus(): string
    {
        $this-&gt;updateStatus(false);

        return $this-&gt;status;
    }

    /**
     * Stops the process.
     *
     * @param int|float $timeout The timeout in seconds
     * @param int       $signal  A POSIX signal to send in case the process has not stop at timeout, default is SIGKILL (9)
     *
     * @return int|null The exit-code of the process or null if it's not running
     */
    public function stop(float $timeout = 10, int $signal = null): ?int
    {
        $timeoutMicro = microtime(true) + $timeout;
        if ($this-&gt;isRunning()) {
            // given SIGTERM may not be defined and that &quot;proc_terminate&quot; uses the constant value and not the constant itself, we use the same here
            $this-&gt;doSignal(15, false);
            do {
                usleep(1000);
            } while ($this-&gt;isRunning() &amp;&amp; microtime(true) &lt; $timeoutMicro);

            if ($this-&gt;isRunning()) {
                // Avoid exception here: process is supposed to be running, but it might have stopped just
                // after this line. In any case, let's silently discard the error, we cannot do anything.
                $this-&gt;doSignal($signal ?: 9, false);
            }
        }

        if ($this-&gt;isRunning()) {
            if (isset($this-&gt;fallbackStatus['pid'])) {
                unset($this-&gt;fallbackStatus['pid']);

                return $this-&gt;stop(0, $signal);
            }
            $this-&gt;close();
        }

        return $this-&gt;exitcode;
    }

    /**
     * Adds a line to the STDOUT stream.
     *
     * @internal
     */
    public function addOutput(string $line)
    {
        $this-&gt;lastOutputTime = microtime(true);

        fseek($this-&gt;stdout, 0, \SEEK_END);
        fwrite($this-&gt;stdout, $line);
        fseek($this-&gt;stdout, $this-&gt;incrementalOutputOffset);
    }

    /**
     * Adds a line to the STDERR stream.
     *
     * @internal
     */
    public function addErrorOutput(string $line)
    {
        $this-&gt;lastOutputTime = microtime(true);

        fseek($this-&gt;stderr, 0, \SEEK_END);
        fwrite($this-&gt;stderr, $line);
        fseek($this-&gt;stderr, $this-&gt;incrementalErrorOutputOffset);
    }

    /**
     * Gets the last output time in seconds.
     */
    public function getLastOutputTime(): ?float
    {
        return $this-&gt;lastOutputTime;
    }

    /**
     * Gets the command line to be executed.
     */
    public function getCommandLine(): string
    {
        return \is_array($this-&gt;commandline) ? implode(' ', array_map($this-&gt;escapeArgument(...), $this-&gt;commandline)) : $this-&gt;commandline;
    }

    /**
     * Gets the process timeout in seconds (max. runtime).
     */
    public function getTimeout(): ?float
    {
        return $this-&gt;timeout;
    }

    /**
     * Gets the process idle timeout in seconds (max. time since last output).
     */
    public function getIdleTimeout(): ?float
    {
        return $this-&gt;idleTimeout;
    }

    /**
     * Sets the process timeout (max. runtime) in seconds.
     *
     * To disable the timeout, set this value to null.
     *
     * @return $this
     *
     * @throws InvalidArgumentException if the timeout is negative
     */
    public function setTimeout(?float $timeout): static
    {
        $this-&gt;timeout = $this-&gt;validateTimeout($timeout);

        return $this;
    }

    /**
     * Sets the process idle timeout (max. time since last output) in seconds.
     *
     * To disable the timeout, set this value to null.
     *
     * @return $this
     *
     * @throws LogicException           if the output is disabled
     * @throws InvalidArgumentException if the timeout is negative
     */
    public function setIdleTimeout(?float $timeout): static
    {
        if (null !== $timeout &amp;&amp; $this-&gt;outputDisabled) {
            throw new LogicException('Idle timeout cannot be set while the output is disabled.');
        }

        $this-&gt;idleTimeout = $this-&gt;validateTimeout($timeout);

        return $this;
    }

    /**
     * Enables or disables the TTY mode.
     *
     * @return $this
     *
     * @throws RuntimeException In case the TTY mode is not supported
     */
    public function setTty(bool $tty): static
    {
        if ('\\' === \DIRECTORY_SEPARATOR &amp;&amp; $tty) {
            throw new RuntimeException('TTY mode is not supported on Windows platform.');
        }

        if ($tty &amp;&amp; !self::isTtySupported()) {
            throw new RuntimeException('TTY mode requires /dev/tty to be read/writable.');
        }

        $this-&gt;tty = $tty;

        return $this;
    }

    /**
     * Checks if the TTY mode is enabled.
     */
    public function isTty(): bool
    {
        return $this-&gt;tty;
    }

    /**
     * Sets PTY mode.
     *
     * @return $this
     */
    public function setPty(bool $bool): static
    {
        $this-&gt;pty = $bool;

        return $this;
    }

    /**
     * Returns PTY state.
     */
    public function isPty(): bool
    {
        return $this-&gt;pty;
    }

    /**
     * Gets the working directory.
     */
    public function getWorkingDirectory(): ?string
    {
        if (null === $this-&gt;cwd) {
            // getcwd() will return false if any one of the parent directories does not have
            // the readable or search mode set, even if the current directory does
            return getcwd() ?: null;
        }

        return $this-&gt;cwd;
    }

    /**
     * Sets the current working directory.
     *
     * @return $this
     */
    public function setWorkingDirectory(string $cwd): static
    {
        $this-&gt;cwd = $cwd;

        return $this;
    }

    /**
     * Gets the environment variables.
     */
    public function getEnv(): array
    {
        return $this-&gt;env;
    }

    /**
     * Sets the environment variables.
     *
     * @param array&lt;string|\Stringable&gt; $env The new environment variables
     *
     * @return $this
     */
    public function setEnv(array $env): static
    {
        $this-&gt;env = $env;

        return $this;
    }

    /**
     * Gets the Process input.
     *
     * @return resource|string|\Iterator|null
     */
    public function getInput()
    {
        return $this-&gt;input;
    }

    /**
     * Sets the input.
     *
     * This content will be passed to the underlying process standard input.
     *
     * @param string|int|float|bool|resource|\Traversable|null $input The content
     *
     * @return $this
     *
     * @throws LogicException In case the process is running
     */
    public function setInput(mixed $input): static
    {
        if ($this-&gt;isRunning()) {
            throw new LogicException('Input cannot be set while the process is running.');
        }

        $this-&gt;input = ProcessUtils::validateInput(__METHOD__, $input);

        return $this;
    }

    /**
     * Performs a check between the timeout definition and the time the process started.
     *
     * In case you run a background process (with the start method), you should
     * trigger this method regularly to ensure the process timeout
     *
     * @throws ProcessTimedOutException In case the timeout was reached
     */
    public function checkTimeout()
    {
        if (self::STATUS_STARTED !== $this-&gt;status) {
            return;
        }

        if (null !== $this-&gt;timeout &amp;&amp; $this-&gt;timeout &lt; microtime(true) - $this-&gt;starttime) {
            $this-&gt;stop(0);

            throw new ProcessTimedOutException($this, ProcessTimedOutException::TYPE_GENERAL);
        }

        if (null !== $this-&gt;idleTimeout &amp;&amp; $this-&gt;idleTimeout &lt; microtime(true) - $this-&gt;lastOutputTime) {
            $this-&gt;stop(0);

            throw new ProcessTimedOutException($this, ProcessTimedOutException::TYPE_IDLE);
        }
    }

    /**
     * @throws LogicException in case process is not started
     */
    public function getStartTime(): float
    {
        if (!$this-&gt;isStarted()) {
            throw new LogicException('Start time is only available after process start.');
        }

        return $this-&gt;starttime;
    }

    /**
     * Defines options to pass to the underlying proc_open().
     *
     * @see https://php.net/proc_open for the options supported by PHP.
     *
     * Enabling the &quot;create_new_console&quot; option allows a subprocess to continue
     * to run after the main process exited, on both Windows and *nix
     */
    public function setOptions(array $options)
    {
        if ($this-&gt;isRunning()) {
            throw new RuntimeException('Setting options while the process is running is not possible.');
        }

        $defaultOptions = $this-&gt;options;
        $existingOptions = ['blocking_pipes', 'create_process_group', 'create_new_console'];

        foreach ($options as $key =&gt; $value) {
            if (!\in_array($key, $existingOptions)) {
                $this-&gt;options = $defaultOptions;
                throw new LogicException(sprintf('Invalid option &quot;%s&quot; passed to &quot;%s()&quot;. Supported options are &quot;%s&quot;.', $key, __METHOD__, implode('&quot;, &quot;', $existingOptions)));
            }
            $this-&gt;options[$key] = $value;
        }
    }

    /**
     * Returns whether TTY is supported on the current operating system.
     */
    public static function isTtySupported(): bool
    {
        static $isTtySupported;

        return $isTtySupported ??= ('/' === \DIRECTORY_SEPARATOR &amp;&amp; stream_isatty(\STDOUT));
    }

    /**
     * Returns whether PTY is supported on the current operating system.
     */
    public static function isPtySupported(): bool
    {
        static $result;

        if (null !== $result) {
            return $result;
        }

        if ('\\' === \DIRECTORY_SEPARATOR) {
            return $result = false;
        }

        return $result = (bool) @proc_open('echo 1 &gt;/dev/null', [['pty'], ['pty'], ['pty']], $pipes);
    }

    /**
     * Creates the descriptors needed by the proc_open.
     */
    private function getDescriptors(): array
    {
        if ($this-&gt;input instanceof \Iterator) {
            $this-&gt;input-&gt;rewind();
        }
        if ('\\' === \DIRECTORY_SEPARATOR) {
            $this-&gt;processPipes = new WindowsPipes($this-&gt;input, !$this-&gt;outputDisabled || $this-&gt;hasCallback);
        } else {
            $this-&gt;processPipes = new UnixPipes($this-&gt;isTty(), $this-&gt;isPty(), $this-&gt;input, !$this-&gt;outputDisabled || $this-&gt;hasCallback);
        }

        return $this-&gt;processPipes-&gt;getDescriptors();
    }

    /**
     * Builds up the callback used by wait().
     *
     * The callbacks adds all occurred output to the specific buffer and calls
     * the user callback (if present) with the received output.
     *
     * @param callable|null $callback The user defined PHP callback
     */
    protected function buildCallback(callable $callback = null): \Closure
    {
        if ($this-&gt;outputDisabled) {
            return function ($type, $data) use ($callback): bool {
                return null !== $callback &amp;&amp; $callback($type, $data);
            };
        }

        $out = self::OUT;

        return function ($type, $data) use ($callback, $out): bool {
            if ($out == $type) {
                $this-&gt;addOutput($data);
            } else {
                $this-&gt;addErrorOutput($data);
            }

            return null !== $callback &amp;&amp; $callback($type, $data);
        };
    }

    /**
     * Updates the status of the process, reads pipes.
     *
     * @param bool $blocking Whether to use a blocking read call
     */
    protected function updateStatus(bool $blocking)
    {
        if (self::STATUS_STARTED !== $this-&gt;status) {
            return;
        }

        $this-&gt;processInformation = proc_get_status($this-&gt;process);
        $running = $this-&gt;processInformation['running'];

        $this-&gt;readPipes($running &amp;&amp; $blocking, '\\' !== \DIRECTORY_SEPARATOR || !$running);

        if ($this-&gt;fallbackStatus &amp;&amp; $this-&gt;isSigchildEnabled()) {
            $this-&gt;processInformation = $this-&gt;fallbackStatus + $this-&gt;processInformation;
        }

        if (!$running) {
            $this-&gt;close();
        }
    }

    /**
     * Returns whether PHP has been compiled with the '--enable-sigchild' option or not.
     */
    protected function isSigchildEnabled(): bool
    {
        if (null !== self::$sigchild) {
            return self::$sigchild;
        }

        if (!\function_exists('phpinfo')) {
            return self::$sigchild = false;
        }

        ob_start();
        phpinfo(\INFO_GENERAL);

        return self::$sigchild = str_contains(ob_get_clean(), '--enable-sigchild');
    }

    /**
     * Reads pipes for the freshest output.
     *
     * @param string $caller   The name of the method that needs fresh outputs
     * @param bool   $blocking Whether to use blocking calls or not
     *
     * @throws LogicException in case output has been disabled or process is not started
     */
    private function readPipesForOutput(string $caller, bool $blocking = false)
    {
        if ($this-&gt;outputDisabled) {
            throw new LogicException('Output has been disabled.');
        }

        $this-&gt;requireProcessIsStarted($caller);

        $this-&gt;updateStatus($blocking);
    }

    /**
     * Validates and returns the filtered timeout.
     *
     * @throws InvalidArgumentException if the given timeout is a negative number
     */
    private function validateTimeout(?float $timeout): ?float
    {
        $timeout = (float) $timeout;

        if (0.0 === $timeout) {
            $timeout = null;
        } elseif ($timeout &lt; 0) {
            throw new InvalidArgumentException('The timeout value must be a valid positive integer or float number.');
        }

        return $timeout;
    }

    /**
     * Reads pipes, executes callback.
     *
     * @param bool $blocking Whether to use blocking calls or not
     * @param bool $close    Whether to close file handles or not
     */
    private function readPipes(bool $blocking, bool $close)
    {
        $result = $this-&gt;processPipes-&gt;readAndWrite($blocking, $close);

        $callback = $this-&gt;callback;
        foreach ($result as $type =&gt; $data) {
            if (3 !== $type) {
                $callback(self::STDOUT === $type ? self::OUT : self::ERR, $data);
            } elseif (!isset($this-&gt;fallbackStatus['signaled'])) {
                $this-&gt;fallbackStatus['exitcode'] = (int) $data;
            }
        }
    }

    /**
     * Closes process resource, closes file handles, sets the exitcode.
     *
     * @return int The exitcode
     */
    private function close(): int
    {
        $this-&gt;processPipes-&gt;close();
        if (\is_resource($this-&gt;process)) {
            proc_close($this-&gt;process);
        }
        $this-&gt;exitcode = $this-&gt;processInformation['exitcode'];
        $this-&gt;status = self::STATUS_TERMINATED;

        if (-1 === $this-&gt;exitcode) {
            if ($this-&gt;processInformation['signaled'] &amp;&amp; 0 &lt; $this-&gt;processInformation['termsig']) {
                // if process has been signaled, no exitcode but a valid termsig, apply Unix convention
                $this-&gt;exitcode = 128 + $this-&gt;processInformation['termsig'];
            } elseif ($this-&gt;isSigchildEnabled()) {
                $this-&gt;processInformation['signaled'] = true;
                $this-&gt;processInformation['termsig'] = -1;
            }
        }

        // Free memory from self-reference callback created by buildCallback
        // Doing so in other contexts like __destruct or by garbage collector is ineffective
        // Now pipes are closed, so the callback is no longer necessary
        $this-&gt;callback = null;

        return $this-&gt;exitcode;
    }

    /**
     * Resets data related to the latest run of the process.
     */
    private function resetProcessData()
    {
        $this-&gt;starttime = null;
        $this-&gt;callback = null;
        $this-&gt;exitcode = null;
        $this-&gt;fallbackStatus = [];
        $this-&gt;processInformation = null;
        $this-&gt;stdout = fopen('php://temp/maxmemory:'.(1024 * 1024), 'w+');
        $this-&gt;stderr = fopen('php://temp/maxmemory:'.(1024 * 1024), 'w+');
        $this-&gt;process = null;
        $this-&gt;latestSignal = null;
        $this-&gt;status = self::STATUS_READY;
        $this-&gt;incrementalOutputOffset = 0;
        $this-&gt;incrementalErrorOutputOffset = 0;
    }

    /**
     * Sends a POSIX signal to the process.
     *
     * @param int  $signal         A valid POSIX signal (see https://php.net/pcntl.constants)
     * @param bool $throwException Whether to throw exception in case signal failed
     *
     * @throws LogicException   In case the process is not running
     * @throws RuntimeException In case --enable-sigchild is activated and the process can't be killed
     * @throws RuntimeException In case of failure
     */
    private function doSignal(int $signal, bool $throwException): bool
    {
        if (null === $pid = $this-&gt;getPid()) {
            if ($throwException) {
                throw new LogicException('Cannot send signal on a non running process.');
            }

            return false;
        }

        if ('\\' === \DIRECTORY_SEPARATOR) {
            exec(sprintf('taskkill /F /T /PID %d 2&gt;&amp;1', $pid), $output, $exitCode);
            if ($exitCode &amp;&amp; $this-&gt;isRunning()) {
                if ($throwException) {
                    throw new RuntimeException(sprintf('Unable to kill the process (%s).', implode(' ', $output)));
                }

                return false;
            }
        } else {
            if (!$this-&gt;isSigchildEnabled()) {
                $ok = @proc_terminate($this-&gt;process, $signal);
            } elseif (\function_exists('posix_kill')) {
                $ok = @posix_kill($pid, $signal);
            } elseif ($ok = proc_open(sprintf('kill -%d %d', $signal, $pid), [2 =&gt; ['pipe', 'w']], $pipes)) {
                $ok = false === fgets($pipes[2]);
            }
            if (!$ok) {
                if ($throwException) {
                    throw new RuntimeException(sprintf('Error while sending signal &quot;%s&quot;.', $signal));
                }

                return false;
            }
        }

        $this-&gt;latestSignal = $signal;
        $this-&gt;fallbackStatus['signaled'] = true;
        $this-&gt;fallbackStatus['exitcode'] = -1;
        $this-&gt;fallbackStatus['termsig'] = $this-&gt;latestSignal;

        return true;
    }

    private function prepareWindowsCommandLine(string $cmd, array &amp;$env): string
    {
        $uid = uniqid('', true);
        $varCount = 0;
        $varCache = [];
        $cmd = preg_replace_callback(
            '/&quot;(?:(
                [^&quot;%!^]*+
                (?:
                    (?: !LF! | &quot;(?:\^[%!^])?+&quot; )
                    [^&quot;%!^]*+
                )++
            ) | [^&quot;]*+ )&quot;/x',
            function ($m) use (&amp;$env, &amp;$varCache, &amp;$varCount, $uid) {
                if (!isset($m[1])) {
                    return $m[0];
                }
                if (isset($varCache[$m[0]])) {
                    return $varCache[$m[0]];
                }
                if (str_contains($value = $m[1], &quot;\0&quot;)) {
                    $value = str_replace(&quot;\0&quot;, '?', $value);
                }
                if (false === strpbrk($value, &quot;\&quot;%!\n&quot;)) {
                    return '&quot;'.$value.'&quot;';
                }

                $value = str_replace(['!LF!', '&quot;^!&quot;', '&quot;^%&quot;', '&quot;^^&quot;', '&quot;&quot;'], [&quot;\n&quot;, '!', '%', '^', '&quot;'], $value);
                $value = '&quot;'.preg_replace('/(\\\\*)&quot;/', '$1$1\\&quot;', $value).'&quot;';
                $var = $uid.++$varCount;

                $env[$var] = $value;

                return $varCache[$m[0]] = '!'.$var.'!';
            },
            $cmd
        );

        $cmd = 'cmd /V:ON /E:ON /D /C ('.str_replace(&quot;\n&quot;, ' ', $cmd).')';
        foreach ($this-&gt;processPipes-&gt;getFiles() as $offset =&gt; $filename) {
            $cmd .= ' '.$offset.'&gt;&quot;'.$filename.'&quot;';
        }

        return $cmd;
    }

    /**
     * Ensures the process is running or terminated, throws a LogicException if the process has a not started.
     *
     * @throws LogicException if the process has not run
     */
    private function requireProcessIsStarted(string $functionName)
    {
        if (!$this-&gt;isStarted()) {
            throw new LogicException(sprintf('Process must be started before calling &quot;%s()&quot;.', $functionName));
        }
    }

    /**
     * Ensures the process is terminated, throws a LogicException if the process has a status different than &quot;terminated&quot;.
     *
     * @throws LogicException if the process is not yet terminated
     */
    private function requireProcessIsTerminated(string $functionName)
    {
        if (!$this-&gt;isTerminated()) {
            throw new LogicException(sprintf('Process must be terminated before calling &quot;%s()&quot;.', $functionName));
        }
    }

    /**
     * Escapes a string to be used as a shell argument.
     */
    private function escapeArgument(?string $argument): string
    {
        if ('' === $argument || null === $argument) {
            return '&quot;&quot;';
        }
        if ('\\' !== \DIRECTORY_SEPARATOR) {
            return &quot;'&quot;.str_replace(&quot;'&quot;, &quot;'\\''&quot;, $argument).&quot;'&quot;;
        }
        if (str_contains($argument, &quot;\0&quot;)) {
            $argument = str_replace(&quot;\0&quot;, '?', $argument);
        }
        if (!preg_match('/[\/()%!^&quot;&lt;&gt;&amp;|\s]/', $argument)) {
            return $argument;
        }
        $argument = preg_replace('/(\\\\+)$/', '$1$1', $argument);

        return '&quot;'.str_replace(['&quot;', '^', '%', '!', &quot;\n&quot;], ['&quot;&quot;', '&quot;^^&quot;', '&quot;^%&quot;', '&quot;^!&quot;', '!LF!'], $argument).'&quot;';
    }

    private function replacePlaceholders(string $commandline, array $env)
    {
        return preg_replace_callback('/&quot;\$\{:([_a-zA-Z]++[_a-zA-Z0-9]*+)\}&quot;/', function ($matches) use ($commandline, $env) {
            if (!isset($env[$matches[1]]) || false === $env[$matches[1]]) {
                throw new InvalidArgumentException(sprintf('Command line is missing a value for parameter &quot;%s&quot;: ', $matches[1]).$commandline);
            }

            return $this-&gt;escapeArgument($env[$matches[1]]);
        }, $commandline);
    }

    private function getDefaultEnv(): array
    {
        $env = getenv();
        $env = ('\\' === \DIRECTORY_SEPARATOR ? array_intersect_ukey($env, $_SERVER, 'strcasecmp') : array_intersect_key($env, $_SERVER)) ?: $env;

        return $_ENV + ('\\' === \DIRECTORY_SEPARATOR ? array_diff_ukey($env, $_ENV, 'strcasecmp') : $env);
    }
}
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