Goatherd\Patch\Installer::applyPatch PHP Method

    public function applyPatch(PackageInterface $package)
    {
        $extra = $package->getExtra();
        if (!isset($extra['patch-path']) || !isset($extra['patch-files'])) {
            throw new \RuntimeException('Need extra `patch-path` and `patch-files` to be defined.');
        }
        $sourcePath = $this->getInstallPath($package);
        $targetPath = $this->vendorDir . DIRECTORY_SEPARATOR . $extra['patch-path'];
        if (!is_dir($targetPath)) {
            throw new \RuntimeException('Patched packages must be installed first. Try to adjust your composer.json.');
        }
        // TODO test source files
        foreach ($extra['patch-files'] as $fn) {
            $source = $sourcePath . DIRECTORY_SEPARATOR . $fn;
            $target = $targetPath . DIRECTORY_SEPARATOR . $fn;
            if (!is_dir($targetPath)) {
                mkdir($targetPath, 0644, true);
            }
            // will replace as needed
            copy($source, $target);
        }
    }