FEATURE #2350 @2h: add pipeline for displaying content

app/CMS/Pipeline/DisplayPipeline.php

@@ -0,0 +1,112 @@
+<?php
+namespace App\CMS\Pipeline;
+
+use App\CMS\Contracts\Content\DisplayPipeline\Pipeline;
+use App\CMS\Contracts\Content\DisplayPipeline\Process;
+use App\CMS\Pipeline\Exceptions\InvalidProcessType;
+use App\Http\Controllers\Controller;
+use App\Models\Content\Content;
+
+class DisplayPipeline implements Pipeline
+{
+    protected $processes = [];
+    protected $beforeStart = null;
+    protected $beforeRender = null;
+
+    /**
+     * Add new process into pipeline
+     *
+     * @param $process
+     *
+     * @return void
+     * @throws InvalidProcessType
+     */
+    function add($process)
+    {
+        $this->checkValidProcess($process);
+
+        $this->processes[] = $process;
+    }
+
+    /**
+     * check if given classname implements Process interface
+     *
+     * @param $classname
+     *
+     * @throws InvalidProcessType
+     */
+    protected function checkValidProcess($classname)
+    {
+        if (!in_array(Process::class, class_implements($classname))) {
+            throw new InvalidProcessType($classname);
+        }
+    }
+
+    /**
+     * @param null $beforeStart
+     */
+    public function setBeforeStart($beforeStart)
+    {
+        $this->checkValidProcess($beforeStart);
+
+        if (!is_null($this->beforeStart)) {
+            array_unshift($this->processes, $this->beforeStart);
+        }
+
+        $this->beforeStart = $beforeStart;
+    }
+
+    /**
+     * @param null $beforeRender
+     */
+    public function setBeforeRender($beforeRender)
+    {
+        $this->checkValidProcess($beforeRender);
+
+        if (!is_null($this->beforeRender)) {
+            array_push($this->processes, $this->beforeRender);
+        }
+
+        $this->beforeRender = $beforeRender;
+    }
+
+    /**
+     * Run pipeline
+     *
+     * @param Content $page
+     *
+     * @return Content
+     */
+    function run(Content $page)
+    {
+        $this->runBeforeStart($page);
+
+        foreach ($this->processes as $process) {
+            /**
+             * @var $run Process
+             */
+            $run = new $process;
+            $run->handle($page);
+        }
+
+        $this->runBeforeRender($page);
+
+        return $page;
+    }
+
+    private function runBeforeStart($page)
+    {
+        if (!is_null($this->beforeStart)) {
+            $process = new $this->beforeStart;
+            $process->handle($page);
+        }
+    }
+
+    private function runBeforeRender($page)
+    {
+        if (!is_null($this->beforeRender)) {
+            $process = new $this->beforeRender;
+            $process->handle($page);
+        }
+    }
+}