Create block placeholder

[MAILPOET-3638]

lib/DI/ContainerConfigurator.php

@@ -331,6 +331,7 @@ class ContainerConfigurator implements IContainerConfigurator {
     $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Footer::class);
     $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Header::class);
     $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Image::class);
+    $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Placeholder::class);
     $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Renderer::class)->setPublic(true);
     $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Social::class);
     $container->autowire(\MailPoet\Newsletter\Renderer\Blocks\Spacer::class);

lib/Newsletter/Renderer/Blocks/Placeholder.php

@@ -0,0 +1,26 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Newsletter\Renderer\Blocks;
+
+use MailPoet\WP\Functions as WPFunctions;
+
+class Placeholder {
+  /** @var WPFunctions */
+  private $wp;
+
+  public function __construct(WPFunctions $wp) {
+    $this->wp = $wp;
+  }
+
+  public function render($element): string {
+    $placeholder = $element['placeholder'];
+    $class = $element['class'] ?? '';
+    $style = $element['style'] ?? '';
+    return '
+      <tr>
+        <td class="' . $this->wp->escAttr($class) . '" style="' . $this->wp->escAttr($style) . '">
+          ' . $this->wp->escHtml($placeholder) . '
+        </td>
+      </tr>';
+  }
+}

lib/Newsletter/Renderer/Blocks/Renderer.php

@@ -34,6 +34,9 @@ class Renderer {
   /** @var Text */
   private $text;
 
+  /** @var Placeholder */
+  private $placeholder;
+
   public function __construct(
     AutomatedLatestContentBlock $ALC,
     Button $button,
@@ -43,7 +46,8 @@ class Renderer {
     Image $image,
     Social $social,
     Spacer $spacer,
-    Text $text
+    Text $text,
+    Placeholder $placeholder
   ) {
     $this->ALC = $ALC;
     $this->button = $button;
@@ -54,6 +58,7 @@ class Renderer {
     $this->social = $social;
     $this->spacer = $spacer;
     $this->text = $text;
+    $this->placeholder = $placeholder;
   }
 
   public function render(NewsletterEntity $newsletter, $data) {
@@ -113,6 +118,8 @@ class Renderer {
         return $this->spacer->render($block);
       case 'text':
         return $this->text->render($block);
+      case 'placeholder':
+        return $this->placeholder->render($block);
     }
     return "<!-- Skipped unsupported block type: {$block['type']} -->";
   }