feat: add XML module, instance of this module represents the feed document

The xml module parses the feed content, reporting the parse status and any detected errors.

Author: Harrison Ifeanyichukwu

src/XML.php

@@ -0,0 +1,86 @@
+<?php
+declare(strict_types = 1);
+
+namespace Forensic\FeedParser;
+
+class XML
+{
+    private $_doc = null;
+    private $_errors = [];
+
+    public function __construct(string $xml = null)
+    {
+        $this->parse($xml);
+    }
+
+    /**
+     * parses the xml string into a document.
+     *
+     *@return boolean
+    */
+    public function parse(string $xml = null)
+    {
+        $this->_doc = null;
+        $this->_errors = [];
+
+        //if no string was provided, bail out
+        if (is_null($xml))
+            return false;
+
+        libxml_use_internal_errors(true);
+        $this->_doc = $doc = new \DOMDocument();
+
+        //if document was loaded successfully, bail out
+        if ($doc->loadXML(trim($xml)))
+            return true;
+
+        foreach (libxml_get_errors() as $error)
+        {
+            switch ($error->level)
+            {
+                //only take error and fatal level errors, ignore warnings
+                case LIBXML_ERR_ERROR:
+                case LIBXML_ERR_FATAL:
+                    $this->_errors[] = $error->message . ' on line ' . $error->line;
+                    break;
+            }
+        }
+        libxml_clear_errors();
+
+        //reset doc to null if error exists
+        if (count($this->_errors) > 0)
+            $this->_doc = null;
+
+        return $this->status();
+    }
+
+    /**
+     * returns the xml document or null if not parsed successful.
+     *
+     *@return \DOMDocument|null
+    */
+    public function document()
+    {
+        return $this->_doc;
+    }
+
+    /**
+     * returns the parser detected errors
+     *
+     *@return array
+    */
+    public function errors()
+    {
+        return $this->_errors;
+    }
+
+    /**
+     * returns the document parse status
+     *
+     *@return boolean
+    */
+    public function status()
+    {
+        return !is_null($this->_doc);
+    }
+}