Added basic placeholder providers for parts.

src/Services/LabelSystem/LabelTextReplacer.php

@@ -0,0 +1,58 @@
+<?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;
+
+
+use App\Services\LabelSystem\PlaceholderProviders\PlaceholderProviderInterface;
+
+class LabelTextReplacer
+{
+    protected $providers;
+
+    public function __construct(iterable $providers)
+    {
+        $this->providers = $providers;
+    }
+
+    public function handlePlaceholder(string $placeholder, object $target): string
+    {
+        foreach ($this->providers as $provider) {
+            /** @var PlaceholderProviderInterface $provider */
+            $ret = $provider->replace($placeholder, $target);
+            if ($ret !== null) {
+                return $ret;
+            }
+        }
+
+        return $placeholder;
+    }
+
+    public function replace(string $lines, object $target): string
+    {
+        $patterns = [
+            '/(%%.*%%)/' => function ($match) use ($target) {
+                return $this->handlePlaceholder($match[0], $target);
+            },
+        ];
+
+        return preg_replace_callback_array($patterns, $lines);
+    }
+}