Reduce code duplication in Handlebars powered styles

src/mibew/libs/classes/Mibew/Handlebars/HandlebarsAwareInterface.php

@@ -0,0 +1,42 @@
+<?php
+/*
+ * This file is a part of Mibew Messenger.
+ *
+ * Copyright 2005-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Mibew\Handlebars;
+
+use Handlebars\Handlebars as HandlebarsEngine;
+
+/**
+ * An interface for all classes that deal with Handlebars template engine.
+ */
+interface HandlebarsAwareInterface
+{
+    /**
+     * Gets an instance of Handlebars template engine.
+     *
+     * @return HandlebarsEngine
+     */
+    public function getHandlebars();
+
+    /**
+     * Sets an instace of Handlebars template engine.
+     *
+     * @param HandlebarsEngine $engine An instance of Handlebars engine.
+     */
+    public function setHandlebars(HandlebarsEngine $engine);
+}

src/mibew/libs/classes/Mibew/Style/AbstractHandlebarsPoweredStyle.php

@@ -0,0 +1,69 @@
+<?php
+/*
+ * This file is a part of Mibew Messenger.
+ *
+ * Copyright 2005-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Mibew\Style;
+
+use Handlebars\Handlebars as HandlebarsEngine;
+use Mibew\Handlebars\HelpersSet;
+use Mibew\Handlebars\HandlebarsAwareInterface;
+
+/**
+ * A base class for all styles that use Handlebars templates engine.
+ */
+abstract class AbstractHandlebarsPoweredStyle extends AbstractStyle implements HandlebarsAwareInterface
+{
+    /**
+     * An instance of Handlebars template engine.
+     *
+     * @var HandlebarsEngine
+     */
+    protected $templateEngine = null;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getHandlebars()
+    {
+        if (is_null($this->templateEngine)) {
+            $templates_loader = new \Handlebars\Loader\FilesystemLoader(
+                MIBEW_FS_ROOT . '/' . $this->getFilesPath() . '/templates_src/server_side/'
+            );
+
+            $this->templateEngine = new \Handlebars\Handlebars(array(
+                'loader' => $templates_loader,
+                'partials_loader' => $templates_loader,
+                'helpers' => new \Handlebars\Helpers(HelpersSet::getHelpers())
+            ));
+
+            // Use custom function to escape strings
+            $this->templateEngine->setEscape('safe_htmlspecialchars');
+            $this->templateEngine->setEscapeArgs(array());
+        }
+
+        return $this->templateEngine;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setHandlebars(HandlebarsEngine $engine)
+    {
+        $this->templateEngine = $engine;
+    }
+}

src/mibew/libs/classes/Mibew/Style/ChatStyle.php

@@ -21,44 +21,12 @@ namespace Mibew\Style;
 
 // Import namespaces and classes of the core
 use Mibew\Settings;
-use Mibew\Handlebars\HelpersSet;
 
 /**
  * Represents a chat style
  */
-class ChatStyle extends AbstractStyle implements StyleInterface
+class ChatStyle extends AbstractHandlebarsPoweredStyle implements StyleInterface
 {
-    /**
-     * Template engine for chat templates.
-     *
-     * @var \Handlebars\Handlebars
-     */
-    protected $templateEngine;
-
-    /**
-     * Object constructor
-     *
-     * @param string $style_name Name of the style
-     */
-    public function __construct($style_name)
-    {
-        parent::__construct($style_name);
-
-        $templates_loader = new \Handlebars\Loader\FilesystemLoader(
-            MIBEW_FS_ROOT . '/' . $this->getFilesPath() . '/templates_src/server_side/'
-        );
-
-        $this->templateEngine = new \Handlebars\Handlebars(array(
-            'loader' => $templates_loader,
-            'partials_loader' => $templates_loader,
-            'helpers' => new \Handlebars\Helpers(HelpersSet::getHelpers())
-        ));
-
-        // Use custom function to escape strings
-        $this->templateEngine->setEscape('safe_htmlspecialchars');
-        $this->templateEngine->setEscapeArgs(array());
-    }
-
     /**
      * Builds base path for style files. This path is relative Mibew root and
      * does not contain neither leading nor trailing slash.
@@ -92,7 +60,7 @@ class ChatStyle extends AbstractStyle implements StyleInterface
         $data['stylePath'] = MIBEW_WEB_ROOT . '/' . $this->getFilesPath();
         $data['styleName'] = $this->getName();
 
-        return $this->templateEngine->render($template_name, $data);
+        return $this->getHandlebars()->render($template_name, $data);
     }
 
     /**

src/mibew/libs/classes/Mibew/Style/PageStyle.php

@@ -21,44 +21,12 @@ namespace Mibew\Style;
 
 // Import namespaces and classes of the core
 use Mibew\Settings;
-use Mibew\Handlebars\HelpersSet;
 
 /**
  * Represents a style for operator pages
  */
-class PageStyle extends AbstractStyle implements StyleInterface
+class PageStyle extends AbstractHandlebarsPoweredStyle implements StyleInterface
 {
-    /**
-     * Template engine for chat templates.
-     *
-     * @var \Handlebars\Handlebars
-     */
-    protected $templateEngine;
-
-    /**
-     * Object constructor
-     *
-     * @param string $style_name Name of the style
-     */
-    public function __construct($style_name)
-    {
-        parent::__construct($style_name);
-
-        $templates_loader = new \Handlebars\Loader\FilesystemLoader(
-            MIBEW_FS_ROOT . '/' . $this->getFilesPath() . '/templates_src/server_side/'
-        );
-
-        $this->templateEngine = new \Handlebars\Handlebars(array(
-            'loader' => $templates_loader,
-            'partials_loader' => $templates_loader,
-            'helpers' => new \Handlebars\Helpers(HelpersSet::getHelpers())
-        ));
-
-        // Use custom function to escape strings
-        $this->templateEngine->setEscape('safe_htmlspecialchars');
-        $this->templateEngine->setEscapeArgs(array());
-    }
-
     /**
      * Builds base path for style files. This path is relative Mibew root and
      * does not contain neither leading nor trailing slash.
@@ -92,7 +60,7 @@ class PageStyle extends AbstractStyle implements StyleInterface
         $data['stylePath'] = MIBEW_WEB_ROOT . '/' . $this->getFilesPath();
         $data['styleName'] = $this->getName();
 
-        return $this->templateEngine->render($template_name, $data);
+        return $this->getHandlebars()->render($template_name, $data);
     }
 
     /**