another vendors shell that only export missing deps in vendors for symfony2

vendors_export

#!/usr/bin/env php
<?php
set_time_limit(0);

$rootDir = dirname(__DIR__);
$vendorDir = $rootDir . '/vendor';

array_shift($argv);

if (!is_dir($vendorDir)) {
    mkdir($vendorDir, 0777, true);
}

$deps = parse_ini_file($rootDir . '/deps', true, INI_SCANNER_RAW);
if (false === $deps) {
    exit("The deps file is not valid ini syntax. Perhaps missing a trailing newline?\n");
}

foreach ($deps as $name => $dep) {
    $dep = array_map('trim', $dep);

    // revision
    $rev = isset($dep['version']) ? "/tags/{$dep['version']}" : '/branches/master';

    // install dir
    $installDir = isset($dep['target']) ? $vendorDir . '/' . $dep['target'] : $vendorDir . '/' . $name;
    if (file_exists($installDir)) {
        echo "> Target dep exists: $name\n";
    } else {
        echo "> Installing $name\n";

        // url
        if (!isset($dep['git'])) {
            exit(sprintf('The "git" value for the "%s" dependency must be set.', $name));
        }
        $url = $dep['git'];
        $githubPos = strpos($url, 'github.com');
        if(false === $githubPos) {
            echo "> $name is not located in github.com\n";
        } else {
            $url = 'https://' . substr($url, $githubPos) . $rev;
        }

        system(sprintf('svn export %s %s', escapeshellarg($url), escapeshellarg($installDir)));
    }
}

// php on windows can't use the shebang line from system()
$interpreter = PHP_OS == 'WINNT' ? 'php.exe' : '';

// Update the bootstrap files
system(sprintf('%s %s %s', $interpreter, escapeshellarg($rootDir . '/vendor/bundles/Sensio/Bundle/DistributionBundle/Resources/bin/build_bootstrap.php'), escapeshellarg($rootDir)));

// Update assets
system(sprintf('%s %s assets:install %s', $interpreter, escapeshellarg($rootDir . '/app/console'), escapeshellarg($rootDir . '/web/')));

// Remove the cache
system(sprintf('%s %s cache:clear --no-warmup', $interpreter, escapeshellarg($rootDir . '/app/console')));