Support for namespaced classes; added e_shims

e_shims is an e107 v2-compatible class for the first namespaced core
class, e107\Shims\All.

e107\Shims\All is built from the e107\Shims\InternalShims trait.

e107\Shims\InternalShims currently implements a resilient replacement
for the PHP internal readfile(), which is needed by issue #3528.

As for how the new namespaced classes are handled, the e107 class
(e107_handlers/e107_class.php) has an updated e107::autoload() which
detects namespaced classes and goes to e107::autoload_namespaced().

Namespaced classes handled by e107 are in the \e107 top-level namespace,
and all sub-levels match directory paths under e_HANDLER.

e107_handlers/Shims/InternalShims.php

@@ -0,0 +1,63 @@
+<?php
+/**
+ * e107 website system
+ *
+ * Copyright (C) 2008-2018 e107 Inc (e107.org)
+ * Released under the terms and conditions of the
+ * GNU General Public License (http://www.gnu.org/licenses/gpl.txt)
+ *
+ * Shims for PHP internal functions
+ */
+
+namespace e107\Shims;
+
+trait InternalShims
+{
+	/**
+	 * Outputs a file
+	 *
+	 * Resilient replacement for PHP internal readfile()
+	 *
+	 * @see https://github.com/e107inc/e107/issues/3528 Why this method was implemented
+	 * @param string $filename The filename being read.
+	 * @param bool $use_include_path You can use the optional second parameter and set it to TRUE,
+	 *                               if you want to search for the file in the include_path, too.
+	 * @param resource $context A context stream resource.
+	 * @return int|bool Returns the number of bytes read from the file.
+	 *                   If an error occurs, FALSE is returned.
+	 */
+	public static function readfile($filename, $use_include_path = FALSE, $context = NULL)
+	{
+		$output = @readfile($filename, $use_include_path, $context);
+		if ($output === NULL)
+		{
+			return self::readfile_alt($filename, $use_include_path, $context);
+		}
+		return $output;
+	}
+
+	/**
+	 * Outputs a file
+	 *
+	 * Alternative implementation using file streams
+	 *
+	 * @param $filename
+	 * @param bool $use_include_path
+	 * @param resource $context
+	 * @return bool|int
+	 */
+	public static function readfile_alt($filename, $use_include_path = FALSE, $context = NULL)
+	{
+		// fopen() silently returns false if there is no context
+		if (!is_resource($context)) $context = stream_context_create();
+
+		$handle = @fopen($filename, 'rb', $use_include_path, $context);
+		if ($handle === FALSE) return FALSE;
+		while (!feof($handle))
+		{
+			echo(fread($handle, 8192));
+		}
+		fclose($handle);
+		return filesize($filename);
+	}
+}

e107_handlers/Shims/e_shims.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * e107 website system
+ *
+ * Copyright (C) 2008-2018 e107 Inc (e107.org)
+ * Released under the terms and conditions of the
+ * GNU General Public License (http://www.gnu.org/licenses/gpl.txt)
+ *
+ * Shims for PHP internal functions
+ */
+
+namespace e107\Shims
+{
+	class All
+	{
+		use InternalShims;
+	}
+
+	class Internal
+	{
+		use InternalShims;
+	}
+}
+
+// e107 v2-style classes
+namespace
+{
+	class e_shims extends \e107\Shims\All
+	{
+	}
+}

e107_handlers/e107_class.php

@@ -203,6 +203,7 @@ class e107
 		'e_parse_shortcode'              => '{e_HANDLER}shortcode_handler.php',
 		'e_plugin'                       => '{e_HANDLER}plugin_class.php',
 		'e_ranks'                        => '{e_HANDLER}e_ranks_class.php',
+		'e_shims'                        => '{e_HANDLER}Shims/e_shims.php',
 		'e_shortcode'                    => '{e_HANDLER}shortcode_handler.php',
 		'e_system_user'                  => '{e_HANDLER}user_model.php',
 		'e_theme'                        => '{e_HANDLER}theme_handler.php',
@@ -4886,6 +4887,14 @@ class e107
 		{
 	        return;
 	    }
+
+		// Detect namespaced class
+		if (strpos($className, '\\') !== false)
+		{
+			self::autoload_namespaced($className);
+			return;
+		}
+
 		$tmp = explode('_', $className);
 
 		//echo 'autoloding...'.$className.'<br />';
@@ -4947,6 +4956,27 @@ class e107
 		}
 	}
 
+	/**
+	 * Autoloading logic for namespaced classes
+	 *
+	 * @param $className
+	 * @return void
+	 */
+	private static function autoload_namespaced($className)
+	{
+		$levels = explode('\\', $className);
+
+		// Guard against classes that are not ours
+		if ($levels[0] != 'e107') return;
+
+		$levels[0] = e_HANDLER;
+		$classPath = implode('/', $levels).'.php';
+		if (is_file($classPath) && is_readable($classPath))
+		{
+			include($classPath);
+		}
+	}
+
 	public function __get($name)
 	{
 		switch ($name)