Added basic placeholder providers for parts.

src/Services/LabelSystem/PlaceholderProviders/PlaceholderProviderInterface.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ * Copyright (C) 2019 - 2020 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace App\Services\LabelSystem\PlaceholderProviders;
+
+
+interface PlaceholderProviderInterface
+{
+
+    /**
+     * Determines the real value of this placeholder.
+     * If the placeholder is not supported, null must be returned.
+     * @param  string  $placeholder The placeholder (e.g. "%%PLACEHOLDER%%") that should be replaced
+     * @param  object  $label_target The object that is targeted by the label
+     * @param  array   $options  A list of options that can be used to specify the generated output further.
+     * @return string|null The real value of this placeholder, null if not supported.
+     */
+    public function replace(string $placeholder, object $label_target, array $options = []): ?string;
+}