10 files changed, 510 insertions, 409 deletions
diff --git a/phpBB/phpbb/template/asset.php b/phpBB/phpbb/template/asset.php
index 7c322cd971..2b10dd8848 100644
--- a/phpBB/phpbb/template/asset.php
+++ b/phpBB/phpbb/template/asset.php
@@ -19,13 +19,18 @@ class phpbb_template_asset
 {
 	protected $components = array();
 
+	/** @var phpbb_filesystem **/
+	protected $phpbb_filesystem;
+
 	/**
 	* Constructor
 	*
 	* @param string $url URL
 	*/
-	public function __construct($url)
+	public function __construct($url, phpbb_filesystem $phpbb_filesystem)
 	{
+		$this->phpbb_filesystem = $phpbb_filesystem;
+
 		$this->set_url($url);
 	}
 
@@ -112,7 +117,7 @@ class phpbb_template_asset
 	*/
 	public function get_url()
 	{
-		return $this->join_url($this->components);
+		return $this->phpbb_filesystem->update_web_root_path($this->join_url($this->components));
 	}
 
 	/**
diff --git a/phpBB/phpbb/template/base.php b/phpBB/phpbb/template/base.php
new file mode 100644
index 0000000000..3778424a96
--- /dev/null
+++ b/phpBB/phpbb/template/base.php
@@ -0,0 +1,148 @@
+<?php
+/**
+*
+* @package phpBB3
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+abstract class phpbb_template_base implements phpbb_template
+{
+	/**
+	* Template context.
+	* Stores template data used during template rendering.
+	*
+	* @var phpbb_template_context
+	*/
+	protected $context;
+
+	/**
+	* Array of filenames assigned to set_filenames
+	*
+	* @var array
+	*/
+	protected $filenames = array();
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function set_filenames(array $filename_array)
+	{
+		$this->filenames = array_merge($this->filenames, $filename_array);
+
+		return $this;
+	}
+
+	/**
+	* Get a filename from the handle
+	*
+	* @param string $handle
+	* @return string
+	*/
+	protected function get_filename_from_handle($handle)
+	{
+		return (isset($this->filenames[$handle])) ? $this->filenames[$handle] : $handle;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function destroy()
+	{
+		$this->context->clear();
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function destroy_block_vars($blockname)
+	{
+		$this->context->destroy_block_vars($blockname);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function assign_vars(array $vararray)
+	{
+		foreach ($vararray as $key => $val)
+		{
+			$this->assign_var($key, $val);
+		}
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function assign_var($varname, $varval)
+	{
+		$this->context->assign_var($varname, $varval);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function append_var($varname, $varval)
+	{
+		$this->context->append_var($varname, $varval);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function assign_block_vars($blockname, array $vararray)
+	{
+		$this->context->assign_block_vars($blockname, $vararray);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function alter_block_array($blockname, array $vararray, $key = false, $mode = 'insert')
+	{
+		return $this->context->alter_block_array($blockname, $vararray, $key, $mode);
+	}
+
+	/**
+	* Calls hook if any is defined.
+	*
+	* @param string $handle Template handle being displayed.
+	* @param string $method Method name of the caller.
+	*/
+	protected function call_hook($handle, $method)
+	{
+		global $phpbb_hook;
+
+		if (!empty($phpbb_hook) && $phpbb_hook->call_hook(array(__CLASS__, $method), $handle, $this))
+		{
+			if ($phpbb_hook->hook_return(array(__CLASS__, $method)))
+			{
+				$result = $phpbb_hook->hook_return_result(array(__CLASS__, $method));
+				return array($result);
+			}
+		}
+
+		return false;
+	}
+}
diff --git a/phpBB/phpbb/template/locator.php b/phpBB/phpbb/template/locator.php
deleted file mode 100644
index f6fd20bcc2..0000000000
--- a/phpBB/phpbb/template/locator.php
+++ /dev/null
@@ -1,163 +0,0 @@
-<?php
-/**
-*
-* @package phpBB3
-* @copyright (c) 2011 phpBB Group
-* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
-*
-*/
-
-/**
-* @ignore
-*/
-if (!defined('IN_PHPBB'))
-{
-	exit;
-}
-
-
-/**
-* Resource locator interface.
-*
-* Objects implementing this interface maintain mapping from template handles
-* to source template file paths and locate templates.
-*
-* Locates style files.
-*
-* Resource locator is aware of styles tree, and can return actual
-* filesystem paths (i.e., the "child" style or the "parent" styles)
-* depending on what files exist.
-*
-* Root paths stored in locator are paths to style directories. Templates are
-* stored in subdirectory that $template_path points to.
-*
-* @package phpBB3
-*/
-interface phpbb_template_locator
-{
-	/**
-	* Sets the template filenames for handles. $filename_array
-	* should be a hash of handle => filename pairs.
-	*
-	* @param array $filename_array Should be a hash of handle => filename pairs.
-	*/
-	public function set_filenames(array $filename_array);
-
-	/**
-	* Determines the filename for a template handle.
-	*
-	* The filename comes from array used in a set_filenames call,
-	* which should have been performed prior to invoking this function.
-	* Return value is a file basename (without path).
-	*
-	* @param $handle string Template handle
-	* @return string Filename corresponding to the template handle
-	*/
-	public function get_filename_for_handle($handle);
-
-	/**
-	* Determines the source file path for a template handle without
-	* regard for styles tree.
-	*
-	* This function returns the path in "primary" style directory
-	* corresponding to the given template handle. That path may or
-	* may not actually exist on the filesystem. Because this function
-	* does not perform stat calls to determine whether the path it
-	* returns actually exists, it is faster than get_source_file_for_handle.
-	*
-	* Use get_source_file_for_handle to obtain the actual path that is
-	* guaranteed to exist (which might come from the parent style
-	* directory if primary style has parent styles).
-	*
-	* This function will trigger an error if the handle was never
-	* associated with a template file via set_filenames.
-	*
-	* @param $handle string Template handle
-	* @return string Path to source file path in primary style directory
-	*/
-	public function get_virtual_source_file_for_handle($handle);
-
-	/**
-	* Determines the source file path for a template handle, accounting
-	* for styles tree and verifying that the path exists.
-	*
-	* This function returns the actual path that may be compiled for
-	* the specified template handle. It will trigger an error if
-	* the template handle was never associated with a template path
-	* via set_filenames or if the template file does not exist on the
-	* filesystem.
-	*
-	* Use get_virtual_source_file_for_handle to just resolve a template
-	* handle to a path without any filesystem or styles tree checks.
-	*
-	* @param string $handle Template handle (i.e. "friendly" template name)
-	* @param bool $find_all If true, each root path will be checked and function
-	*				will return array of files instead of string and will not
-	*				trigger a error if template does not exist
-	* @return string Source file path
-	*/
-	public function get_source_file_for_handle($handle, $find_all = false);
-
-	/**
-	* Obtains a complete filesystem path for a file in a style.
-	*
-	* This function traverses the style tree (selected style and
-	* its parents in order, if inheritance is being used) and finds
-	* the first file on the filesystem matching specified relative path,
-	* or the first of the specified paths if more than one path is given.
-	*
-	* This function can be used to determine filesystem path of any
-	* file under any style, with the consequence being that complete
-	* relative to the style directory path must be provided as an argument.
-	*
-	* In particular, this function can be used to locate templates
-	* and javascript files.
-	*
-	* For locating templates get_first_template_location should be used
-	* as it prepends the configured template path to the template basename.
-	*
-	* Note: "selected style" is whatever style the style resource locator
-	* is configured for.
-	*
-	* The return value then will be a path, relative to the current
-	* directory or absolute, to the first existing file in the selected
-	* style or its closest parent.
-	*
-	* If the selected style does not have the file being searched,
-	* (and if inheritance is involved, none of the parents have it either),
-	* false will be returned.
-	*
-	* Multiple files can be specified, in which case the first file in
-	* the list that can be found on the filesystem is returned.
-	*
-	* If multiple files are specified and inheritance is involved,
-	* first each of the specified files is checked in the selected style,
-	* then each of the specified files is checked in the immediate parent,
-	* etc.
-	*
-	* Specifying true for $return_default will cause the function to
-	* return the first path which was checked for existence in the event
-	* that the template file was not found, instead of false.
-	* This is always a path in the selected style itself, not any of its
-	* parents.
-	*
-	* If $return_full_path is false, then instead of returning a usable
-	* path (when the file is found) the file's path relative to the style
-	* directory will be returned. This is the same path as was given to
-	* the function as a parameter. This can be used to check which of the
-	* files specified in $files exists. Naturally this requires passing
-	* more than one file in $files.
-	*
-	* @param array $files List of files to locate.
-	* @param bool $return_default Determines what to return if file does not
-	*				exist. If true, function will return location where file is
-	*				supposed to be. If false, function will return false.
-	* @param bool $return_full_path If true, function will return full path
-	*				to file. If false, function will return file name. This
-	*				parameter can be used to check which one of set of files
-	*				is available.
-	* @return string or boolean Source file path if file exists or $return_default is
-	*				true. False if file does not exist and $return_default is false
-	*/
-	public function get_first_file_location($files, $return_default = false, $return_full_path = true);
-}
diff --git a/phpBB/phpbb/template/template.php b/phpBB/phpbb/template/template.php
index 89a01e924d..6b9c331a3e 100644
--- a/phpBB/phpbb/template/template.php
+++ b/phpBB/phpbb/template/template.php
@@ -34,14 +34,32 @@ interface phpbb_template
 	public function set_filenames(array $filename_array);
 
 	/**
-	* Sets the style names/paths corresponding to style hierarchy being compiled
-	* and/or rendered.
+	* Get the style tree of the style preferred by the current user
 	*
-	* @param array $style_names List of style names in inheritance tree order
-	* @param array $style_paths List of style paths in inheritance tree order
+	* @return array Style tree, most specific first
+	*/
+	public function get_user_style();
+
+	/**
+	* Set style location based on (current) user's chosen style.
+	*
+	* @param array $style_directories The directories to add style paths for
+	* 	E.g. array('ext/foo/bar/styles', 'styles')
+	* 	Default: array('styles') (phpBB's style directory)
+	* @return phpbb_template $this
+	*/
+	public function set_style($style_directories = array('styles'));
+
+	/**
+	* Set custom style location (able to use directory outside of phpBB).
+	*
+	* Note: Templates are still compiled to phpBB's cache directory.
+	*
+	* @param string|array $names Array of names or string of name of template(s) in inheritance tree order, used by extensions.
+	* @param string|array or string $paths Array of style paths, relative to current root directory
 	* @return phpbb_template $this
 	*/
-	public function set_style_names(array $style_names, array $style_paths);
+	public function set_custom_style($names, $paths);
 
 	/**
 	* Clears all variables and blocks assigned to this template.
diff --git a/phpBB/phpbb/template/twig/environment.php b/phpBB/phpbb/template/twig/environment.php
index b60cd72325..612519db69 100644
--- a/phpBB/phpbb/template/twig/environment.php
+++ b/phpBB/phpbb/template/twig/environment.php
@@ -23,9 +23,15 @@ class phpbb_template_twig_environment extends Twig_Environment
 	/** @var phpbb_config */
 	protected $phpbb_config;
 
+	/** @var phpbb_filesystem */
+	protected $phpbb_filesystem;
+
 	/** @var string */
 	protected $phpbb_root_path;
 
+	/** @var string */
+	protected $web_root_path;
+
 	/** @var array **/
 	protected $namespace_look_up_order = array('__main__');
 
@@ -38,11 +44,14 @@ class phpbb_template_twig_environment extends Twig_Environment
 	* @param Twig_LoaderInterface $loader
 	* @param array $options Array of options to pass to Twig
 	*/
-	public function __construct($phpbb_config, $phpbb_extensions, $phpbb_root_path, Twig_LoaderInterface $loader = null, $options = array())
+	public function __construct($phpbb_config, $phpbb_extensions, phpbb_filesystem $phpbb_filesystem, Twig_LoaderInterface $loader = null, $options = array())
 	{
 		$this->phpbb_config = $phpbb_config;
 		$this->phpbb_extensions = $phpbb_extensions;
-		$this->phpbb_root_path = $phpbb_root_path;
+
+		$this->phpbb_filesystem = $phpbb_filesystem;
+		$this->phpbb_root_path = $this->phpbb_filesystem->get_phpbb_root_path();
+		$this->web_root_path = $this->phpbb_filesystem->get_web_root_path();
 
 		return parent::__construct($loader, $options);
 	}
@@ -80,6 +89,26 @@ class phpbb_template_twig_environment extends Twig_Environment
 	}
 
 	/**
+	* Get the web root path
+	*
+	* @return string
+	*/
+	public function get_web_root_path()
+	{
+		return $this->web_root_path;
+	}
+
+	/**
+	* Get the phpbb_filesystem object
+	*
+	* @return phpbb_filesystem
+	*/
+	public function get_filesystem()
+	{
+		return $this->phpbb_filesystem;
+	}
+
+	/**
 	* Get the namespace look up order
 	*
 	* @return array
@@ -137,4 +166,39 @@ class phpbb_template_twig_environment extends Twig_Environment
 			return parent::loadTemplate($name, $index);
 		}
 	}
+
+	/**
+	 * Finds a template by name.
+	 *
+	 * @param string  $name  The template name
+	 * @return string
+	 */
+	public function findTemplate($name)
+	{
+		if (strpos($name, '@') === false)
+		{
+			foreach ($this->getNamespaceLookUpOrder() as $namespace)
+			{
+				try
+				{
+					if ($namespace === '__main__')
+					{
+						return parent::getLoader()->getCacheKey($name);
+					}
+
+					return parent::getLoader()->getCacheKey('@' . $namespace . '/' . $name);
+				}
+				catch (Twig_Error_Loader $e)
+				{
+				}
+			}
+
+			// We were unable to load any templates
+			throw $e;
+		}
+		else
+		{
+			return parent::getLoader()->getCacheKey($name);
+		}
+	}
 }
diff --git a/phpBB/phpbb/template/twig/lexer.php b/phpBB/phpbb/template/twig/lexer.php
index 3534311b7a..16a693cd7c 100644
--- a/phpBB/phpbb/template/twig/lexer.php
+++ b/phpBB/phpbb/template/twig/lexer.php
@@ -75,7 +75,7 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 
 		// Fix tokens that may have inline variables (e.g. <!-- DEFINE $TEST = '{FOO}')
 		$code = $this->fix_inline_variable_tokens(array(
-			'DEFINE.+=',
+			'DEFINE \$[a-zA-Z0-9_]+ =',
 			'INCLUDE',
 			'INCLUDEPHP',
 			'INCLUDEJS',
@@ -130,7 +130,7 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 			// E.g. 'asdf'"' -> asdf'"
 			// E.g. "asdf'"" -> asdf'"
 			// E.g. 'asdf'" -> 'asdf'"
-			$matches[2] = preg_replace('#^([\'"])?(.+?)\1$#', '$2', $matches[2]);
+			$matches[2] = preg_replace('#^([\'"])?(.*?)\1$#', '$2', $matches[2]);
 
 			// Replace template variables with start/end to parse variables (' ~ TEST ~ '.html)
 			$matches[2] = preg_replace('#{([a-zA-Z0-9_\.$]+)}#', "'~ \$1 ~'", $matches[2]);
@@ -161,6 +161,9 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 			$subset = trim(substr($matches[2], 1, -1)); // Remove parenthesis
 			$body = $matches[3];
 
+			// Replace <!-- BEGINELSE -->
+			$body = str_replace('<!-- BEGINELSE -->', '{% else %}', $body);
+
 			// Is the designer wanting to call another loop in a loop?
 			// <!-- BEGIN loop -->
 			// <!-- BEGIN !loop2 -->
@@ -205,9 +208,6 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 			return "{% for {$name} in {$parent}{$name}{$subset} %}{$body}{% endfor %}";
 		};
 
-		// Replace <!-- BEGINELSE --> correctly, only needs to be done once
-		$code = str_replace('<!-- BEGINELSE -->', '{% else %}', $code);
-
 		return preg_replace_callback('#<!-- BEGIN ([!a-zA-Z0-9_]+)(\([0-9,\-]+\))? -->(.+?)<!-- END \1 -->#s', $callback, $code);
 	}
 
@@ -219,25 +219,28 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 	*/
 	protected function fix_if_tokens($code)
 	{
+		// Replace ELSE IF with ELSEIF
+		$code = preg_replace('#<!-- ELSE IF (.+?) -->#', '<!-- ELSEIF $1 -->', $code);
+
+		// Replace our "div by" with Twig's divisibleby (Twig does not like test names with spaces)
+		$code = preg_replace('# div by ([0-9]+)#', ' divisibleby($1)', $code);
+
 		$callback = function($matches)
 		{
 			$inner = $matches[2];
 			// Replace $TEST with definition.TEST
-			$inner = preg_replace('#\s\$([a-zA-Z_0-9]+)#', ' definition.$1', $inner);
+			$inner = preg_replace('#(\s\(?!?)\$([a-zA-Z_0-9]+)#', '$1definition.$2', $inner);
 
 			// Replace .foo with loops.foo|length
-			$inner = preg_replace('#\s\.([a-zA-Z_0-9]+)([^a-zA-Z_0-9\.])#', ' loops.$1|length$2', $inner);
+			$inner = preg_replace('#(\s\(?!?)\.([a-zA-Z_0-9]+)([^a-zA-Z_0-9\.])#', '$1loops.$2|length$3', $inner);
 
 			// Replace .foo.bar with foo.bar|length
-			$inner = preg_replace('#\s\.([a-zA-Z_0-9\.]+)([^a-zA-Z_0-9\.])#', ' $1|length$2', $inner);
+			$inner = preg_replace('#(\s\(?!?)\.([a-zA-Z_0-9\.]+)([^a-zA-Z_0-9\.])#', '$1$2|length$3', $inner);
 
 			return "<!-- {$matches[1]}IF{$inner}-->";
 		};
 
-		// Replace our "div by" with Twig's divisibleby (Twig does not like test names with spaces)
-		$code = preg_replace('# div by ([0-9]+)#', ' divisibleby($1)', $code);
-
-		return preg_replace_callback('#<!-- (ELSE)?IF((.*)[\s][\$|\.|!]([^\s]+)(.*))-->#', $callback, $code);
+		return preg_replace_callback('#<!-- (ELSE)?IF((.*?) \(?!?[\$|\.]([^\s]+)(.*?))-->#', $callback, $code);
 	}
 
 	/**
@@ -261,10 +264,10 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 		*/
 
 		// Replace <!-- DEFINE $NAME with {% DEFINE definition.NAME
-		$code = preg_replace('#<!-- DEFINE \$(.*)-->#', '{% DEFINE $1 %}', $code);
+		$code = preg_replace('#<!-- DEFINE \$(.*?) -->#', '{% DEFINE $1 %}', $code);
 
 		// Changing UNDEFINE NAME to DEFINE NAME = null to save from creating an extra token parser/node
-		$code = preg_replace('#<!-- UNDEFINE \$(.*)-->#', '{% DEFINE $1= null %}', $code);
+		$code = preg_replace('#<!-- UNDEFINE \$(.*?)-->#', '{% DEFINE $1= null %}', $code);
 
 		// Replace all of our variables, {$VARNAME}, with Twig style, {{ definition.VARNAME }}
 		$code = preg_replace('#{\$([a-zA-Z0-9_\.]+)}#', '{{ definition.$1 }}', $code);
diff --git a/phpBB/phpbb/template/twig/loader.php b/phpBB/phpbb/template/twig/loader.php
new file mode 100644
index 0000000000..0829e519f7
--- /dev/null
+++ b/phpBB/phpbb/template/twig/loader.php
@@ -0,0 +1,150 @@
+<?php
+/**
+*
+* @package phpBB3
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+/**
+* Twig Template loader
+* @package phpBB3
+*/
+class phpbb_template_twig_loader extends Twig_Loader_Filesystem
+{
+	protected $safe_directories = array();
+
+	/**
+	* Set safe directories
+	*
+	* @param array $directories Array of directories that are safe (empty to clear)
+	* @return Twig_Loader_Filesystem
+	*/
+	public function setSafeDirectories($directories = array())
+	{
+		$this->safe_directories = array();
+
+		if (!empty($directories))
+		{
+			foreach ($directories as $directory)
+			{
+				$this->addSafeDirectory($directory);
+			}
+		}
+
+		return $this;
+	}
+
+	/**
+	* Add safe directory
+	*
+	* @param string $directory Directory that should be added
+	* @return Twig_Loader_Filesystem
+	*/
+	public function addSafeDirectory($directory)
+	{
+		$directory = phpbb_realpath($directory);
+
+		if ($directory !== false)
+		{
+			$this->safe_directories[] = $directory;
+		}
+
+		return $this;
+	}
+
+	/**
+	* Get current safe directories
+	*
+	* @return array
+	*/
+	public function getSafeDirectories()
+	{
+		return $this->safe_directories;
+	}
+
+	/**
+	* Override for parent::validateName()
+	*
+	* This is done because we added support for safe directories, and when Twig
+	*	findTemplate() is called, validateName() is called first, which would
+	*	always throw an exception if the file is outside of the configured
+	*	template directories.
+	*/
+	protected function validateName($name)
+	{
+		return;
+	}
+
+	/**
+	* Find the template
+	*
+	* Override for Twig_Loader_Filesystem::findTemplate to add support
+	*	for loading from safe directories.
+	*/
+	protected function findTemplate($name)
+	{
+		$name = (string) $name;
+
+		// normalize name
+		$name = preg_replace('#/{2,}#', '/', strtr($name, '\\', '/'));
+
+		// If this is in the cache we can skip the entire process below
+		//	as it should have already been validated
+		if (isset($this->cache[$name])) {
+			return $this->cache[$name];
+		}
+
+		// First, find the template name. The override above of validateName
+		//	causes the validateName process to be skipped for this call
+		$file = parent::findTemplate($name);
+
+		try
+		{
+			// Try validating the name (which may throw an exception)
+			parent::validateName($name);
+		}
+		catch (Twig_Error_Loader $e)
+		{
+			if (strpos($e->getRawMessage(), 'Looks like you try to load a template outside configured directories') === 0)
+			{
+				// Ok, so outside of the configured template directories, we
+				//	can now check if we're within a "safe" directory
+
+				// Find the real path of the directory the file is in
+				$directory = phpbb_realpath(dirname($file));
+
+				if ($directory === false)
+				{
+					// Some sort of error finding the actual path, must throw the exception
+					throw $e;
+				}
+
+				foreach ($this->safe_directories as $safe_directory)
+				{
+					if (strpos($directory, $safe_directory) === 0)
+					{
+						// The directory being loaded is below a directory
+						// that is "safe". We're good to load it!
+						return $file;
+					}
+				}
+			}
+
+			// Not within any safe directories
+			throw $e;
+		}
+
+		// No exception from validateName, safe to load.
+		return $file;
+	}
+}
diff --git a/phpBB/phpbb/template/twig/node/event.php b/phpBB/phpbb/template/twig/node/event.php
index 4533151d05..c94e5fdf20 100644
--- a/phpBB/phpbb/template/twig/node/event.php
+++ b/phpBB/phpbb/template/twig/node/event.php
@@ -43,7 +43,7 @@ class phpbb_template_twig_node_event extends Twig_Node
 	{
 		$compiler->addDebugInfo($this);
 
-		$location = $this->listener_directory . $this->getNode('expr')->getAttribute('name') . '_listener';
+		$location = $this->listener_directory . $this->getNode('expr')->getAttribute('name');
 
 		foreach ($this->environment->get_phpbb_extensions() as $ext_namespace => $ext_path)
 		{
diff --git a/phpBB/phpbb/template/twig/node/includeasset.php b/phpBB/phpbb/template/twig/node/includeasset.php
index 1cab416c79..8629395898 100644
--- a/phpBB/phpbb/template/twig/node/includeasset.php
+++ b/phpBB/phpbb/template/twig/node/includeasset.php
@@ -33,17 +33,17 @@ abstract class phpbb_template_twig_node_includeasset extends Twig_Node
 			->write("\$asset_file = ")
 			->subcompile($this->getNode('expr'))
 			->raw(";\n")
-			->write("\$asset = new phpbb_template_asset(\$asset_file);\n")
+			->write("\$asset = new phpbb_template_asset(\$asset_file, \$this->getEnvironment()->get_filesystem());\n")
 			->write("if (substr(\$asset_file, 0, 2) !== './' && \$asset->is_relative()) {\n")
 			->indent()
 				->write("\$asset_path = \$asset->get_path();")
 				->write("\$local_file = \$this->getEnvironment()->get_phpbb_root_path() . \$asset_path;\n")
 				->write("if (!file_exists(\$local_file)) {\n")
 				->indent()
-					->write("\$local_file = \$this->getEnvironment()->getLoader()->getCacheKey(\$asset_path);\n")
+					->write("\$local_file = \$this->getEnvironment()->findTemplate(\$asset_path);\n")
 					->write("\$asset->set_path(\$local_file, true);\n")
 				->outdent()
-				->write("\$asset->add_assets_version({$config['assets_version']});\n")
+				->write("\$asset->add_assets_version('{$config['assets_version']}');\n")
 				->write("\$asset_file = \$asset->get_url();\n")
 				->write("}\n")
 			->outdent()
diff --git a/phpBB/phpbb/template/twig/twig.php b/phpBB/phpbb/template/twig/twig.php
index 6cff1bb8e4..3aa063ffc6 100644
--- a/phpBB/phpbb/template/twig/twig.php
+++ b/phpBB/phpbb/template/twig/twig.php
@@ -19,16 +19,9 @@ if (!defined('IN_PHPBB'))
 * Twig Template class.
 * @package phpBB3
 */
-class phpbb_template_twig implements phpbb_template
+class phpbb_template_twig extends phpbb_template_base
 {
 	/**
-	* Template context.
-	* Stores template data used during template rendering.
-	* @var phpbb_template_context
-	*/
-	protected $context;
-
-	/**
 	* Path of the cache directory for the template
 	*
 	* Cannot be changed during runtime.
@@ -38,16 +31,16 @@ class phpbb_template_twig implements phpbb_template
 	private $cachepath = '';
 
 	/**
-	* phpBB root path
-	* @var string
+	* phpBB filesystem
+	* @var phpbb_filesystem
 	*/
-	protected $phpbb_root_path;
+	protected $phpbb_filesystem;
 
 	/**
-	* adm relative path
+	* phpBB root path
 	* @var string
 	*/
-	protected $adm_relative_path;
+	protected $phpbb_root_path;
 
 	/**
 	* PHP file extension
@@ -75,16 +68,6 @@ class phpbb_template_twig implements phpbb_template
 	protected $extension_manager;
 
 	/**
-	* Name of the style that the template being compiled and/or rendered
-	* belongs to, and its parents, in inheritance tree order.
-	*
-	* Used to invoke style-specific template events.
-	*
-	* @var array
-	*/
-	protected $style_names;
-
-	/**
 	* Twig Environment
 	*
 	* @var Twig_Environment
@@ -92,42 +75,33 @@ class phpbb_template_twig implements phpbb_template
 	protected $twig;
 
 	/**
-	* Array of filenames assigned to set_filenames
-	*
-	* @var array
-	*/
-	protected $filenames = array();
-
-	/**
 	* Constructor.
 	*
-	* @param string $phpbb_root_path phpBB root path
-	* @param string $php_ext php extension (typically 'php')
+	* @param phpbb_filesystem $phpbb_filesystem
 	* @param phpbb_config $config
 	* @param phpbb_user $user
 	* @param phpbb_template_context $context template context
 	* @param phpbb_extension_manager $extension_manager extension manager, if null then template events will not be invoked
-	* @param string $adm_relative_path relative path to adm directory
 	*/
-	public function __construct($phpbb_root_path, $php_ext, $config, $user, phpbb_template_context $context, phpbb_extension_manager $extension_manager = null, $adm_relative_path = null)
+	public function __construct(phpbb_filesystem $phpbb_filesystem, $config, $user, phpbb_template_context $context, phpbb_extension_manager $extension_manager = null)
 	{
-		$this->phpbb_root_path = $phpbb_root_path;
-		$this->adm_relative_path = $adm_relative_path;
-		$this->php_ext = $php_ext;
+		$this->phpbb_filesystem = $phpbb_filesystem;
+		$this->phpbb_root_path = $phpbb_filesystem->get_phpbb_root_path();
+		$this->php_ext = $phpbb_filesystem->get_php_ext();
 		$this->config = $config;
 		$this->user = $user;
 		$this->context = $context;
 		$this->extension_manager = $extension_manager;
 
-		$this->cachepath = $phpbb_root_path . 'cache/twig/';
+		$this->cachepath = $this->phpbb_root_path . 'cache/twig/';
 
 		// Initiate the loader, __main__ namespace paths will be setup later in set_style_names()
-		$loader = new Twig_Loader_Filesystem('');
+		$loader = new phpbb_template_twig_loader('');
 
 		$this->twig = new phpbb_template_twig_environment(
 			$this->config,
 			($this->extension_manager) ? $this->extension_manager->all_enabled() : array(),
-			$this->phpbb_root_path,
+			$this->phpbb_filesystem,
 			$loader,
 			array(
 				'cache'			=> (defined('IN_INSTALL')) ? false : $this->cachepath,
@@ -147,6 +121,12 @@ class phpbb_template_twig implements phpbb_template
 		$lexer = new phpbb_template_twig_lexer($this->twig);
 
 		$this->twig->setLexer($lexer);
+
+		// Add admin namespace
+		if ($this->phpbb_filesystem->get_adm_relative_path() !== null && is_dir($this->phpbb_root_path . $this->phpbb_filesystem->get_adm_relative_path() . 'style/'))
+		{
+			$this->twig->getLoader()->setPaths($this->phpbb_root_path . $this->phpbb_filesystem->get_adm_relative_path() . 'style/', 'admin');
+		}
 	}
 
 	/**
@@ -165,51 +145,94 @@ class phpbb_template_twig implements phpbb_template
 	}
 
 	/**
-	* Sets the template filenames for handles.
+	* Get the style tree of the style preferred by the current user
 	*
-	* @param array $filename_array Should be a hash of handle => filename pairs.
-	* @return phpbb_template $this
+	* @return array Style tree, most specific first
 	*/
-	public function set_filenames(array $filename_array)
+	public function get_user_style()
 	{
-		$this->filenames = array_merge($this->filenames, $filename_array);
+		$style_list = array(
+			$this->user->style['style_path'],
+		);
 
-		return $this;
+		if ($this->user->style['style_parent_id'])
+		{
+			$style_list = array_merge($style_list, array_reverse(explode('/', $this->user->style['style_parent_tree'])));
+		}
+
+		return $style_list;
 	}
 
 	/**
-	* Sets the style names/paths corresponding to style hierarchy being compiled
-	* and/or rendered.
+	* Set style location based on (current) user's chosen style.
 	*
-	* @param array $style_names List of style names in inheritance tree order
-	* @param array $style_paths List of style paths in inheritance tree order
-	* @param bool $is_core True if the style names are the "core" styles for this page load
-	* 	Core means the main phpBB template files
+	* @param array $style_directories The directories to add style paths for
+	* 	E.g. array('ext/foo/bar/styles', 'styles')
+	* 	Default: array('styles') (phpBB's style directory)
 	* @return phpbb_template $this
 	*/
-	public function set_style_names(array $style_names, array $style_paths, $is_core = false)
+	public function set_style($style_directories = array('styles'))
 	{
-		$this->style_names = $style_names;
+		if ($style_directories !== array('styles') && $this->twig->getLoader()->getPaths('core') === array())
+		{
+			// We should set up the core styles path since not already setup
+			$this->set_style();
+		}
 
-		// Set as __main__ namespace
-		$this->twig->getLoader()->setPaths($style_paths);
+		$names = $this->get_user_style();
 
-		// Core style namespace from phpbb_style::set_style()
-		if ($is_core)
+		$paths = array();
+		foreach ($style_directories as $directory)
 		{
-			$this->twig->getLoader()->setPaths($style_paths, 'core');
+			foreach ($names as $name)
+			{
+				$path = $this->phpbb_root_path . trim($directory, '/') . "/{$name}/";
+				$template_path = $path . 'template/';
+
+				if (is_dir($template_path))
+				{
+					// Add the base style directory as a safe directory
+					$this->twig->getLoader()->addSafeDirectory($path);
+
+					$paths[] = $template_path;
+				}
+			}
 		}
 
-		// Add admin namespace
-		if (is_dir($this->phpbb_root_path . $this->adm_relative_path . 'style/'))
+		// If we're setting up the main phpBB styles directory and the core
+		// namespace isn't setup yet, we will set it up now
+		if ($style_directories === array('styles') && $this->twig->getLoader()->getPaths('core') === array())
 		{
-			$this->twig->getLoader()->setPaths($this->phpbb_root_path . $this->adm_relative_path . 'style/', 'admin');
+			// Set up the core style paths namespace
+			$this->twig->getLoader()->setPaths($paths, 'core');
 		}
 
+		$this->set_custom_style($names, $paths);
+
+		return $this;
+	}
+
+	/**
+	* Set custom style location (able to use directory outside of phpBB).
+	*
+	* Note: Templates are still compiled to phpBB's cache directory.
+	*
+	* @param string|array $names Array of names or string of name of template(s) in inheritance tree order, used by extensions.
+	* @param string|array or string $paths Array of style paths, relative to current root directory
+	* @return phpbb_template $this
+	*/
+	public function set_custom_style($names, $paths)
+	{
+		$paths = (is_string($paths)) ? array($paths) : $paths;
+		$names = (is_string($names)) ? array($names) : $names;
+
+		// Set as __main__ namespace
+		$this->twig->getLoader()->setPaths($paths);
+
 		// Add all namespaces for all extensions
 		if ($this->extension_manager instanceof phpbb_extension_manager)
 		{
-			$style_names[] = 'all';
+			$names[] = 'all';
 
 			foreach ($this->extension_manager->all_enabled() as $ext_namespace => $ext_path)
 			{
@@ -217,13 +240,17 @@ class phpbb_template_twig implements phpbb_template
 				$namespace = str_replace('/', '_', $ext_namespace);
 				$paths = array();
 
-				foreach ($style_names as $style_name)
+				foreach ($names as $style_name)
 				{
-					$ext_style_path = $ext_path . 'styles/' . $style_name . '/template';
+					$ext_style_path = $ext_path . 'styles/' . $style_name . '/';
+					$ext_style_template_path = $ext_style_path . 'template/';
 
-					if (is_dir($ext_style_path))
+					if (is_dir($ext_style_template_path))
 					{
-						$paths[] = $ext_style_path;
+						// Add the base style directory as a safe directory
+						$this->twig->getLoader()->addSafeDirectory($ext_style_path);
+
+						$paths[] = $ext_style_template_path;
 					}
 				}
 
@@ -235,31 +262,6 @@ class phpbb_template_twig implements phpbb_template
 	}
 
 	/**
-	* Clears all variables and blocks assigned to this template.
-	*
-	* @return phpbb_template $this
-	*/
-	public function destroy()
-	{
-		$this->context = array();
-
-		return $this;
-	}
-
-	/**
-	* Reset/empty complete block
-	*
-	* @param string $blockname Name of block to destroy
-	* @return phpbb_template $this
-	*/
-	public function destroy_block_vars($blockname)
-	{
-		$this->context->destroy_block_vars($blockname);
-
-		return $this;
-	}
-
-	/**
 	* Display a template for provided handle.
 	*
 	* The template will be loaded and compiled, if necessary, first.
@@ -283,28 +285,6 @@ class phpbb_template_twig implements phpbb_template
 	}
 
 	/**
-	* Calls hook if any is defined.
-	*
-	* @param string $handle Template handle being displayed.
-	* @param string $method Method name of the caller.
-	*/
-	protected function call_hook($handle, $method)
-	{
-		global $phpbb_hook;
-
-		if (!empty($phpbb_hook) && $phpbb_hook->call_hook(array(__CLASS__, $method), $handle, $this))
-		{
-			if ($phpbb_hook->hook_return(array(__CLASS__, $method)))
-			{
-				$result = $phpbb_hook->hook_return_result(array(__CLASS__, $method));
-				return array($result);
-			}
-		}
-
-		return false;
-	}
-
-	/**
 	* Display the handle and assign the output to a template variable
 	* or return the compiled result.
 	*
@@ -326,104 +306,11 @@ class phpbb_template_twig implements phpbb_template
 	}
 
 	/**
-	* Assign key variable pairs from an array
-	*
-	* @param array $vararray A hash of variable name => value pairs
-	* @return phpbb_template $this
-	*/
-	public function assign_vars(array $vararray)
-	{
-		foreach ($vararray as $key => $val)
-		{
-			$this->assign_var($key, $val);
-		}
-
-		return $this;
-	}
-
-	/**
-	* Assign a single scalar value to a single key.
-	*
-	* Value can be a string, an integer or a boolean.
-	*
-	* @param string $varname Variable name
-	* @param string $varval Value to assign to variable
-	* @return phpbb_template $this
-	*/
-	public function assign_var($varname, $varval)
-	{
-		$this->context->assign_var($varname, $varval);
-
-		return $this;
-	}
-
-	/**
-	* Append text to the string value stored in a key.
-	*
-	* Text is appended using the string concatenation operator (.).
-	*
-	* @param string $varname Variable name
-	* @param string $varval Value to append to variable
-	* @return phpbb_template $this
-	*/
-	public function append_var($varname, $varval)
-	{
-		$this->context->append_var($varname, $varval);
-
-		return $this;
-	}
-
-	/**
-	* Assign key variable pairs from an array to a specified block
-	* @param string $blockname Name of block to assign $vararray to
-	* @param array $vararray A hash of variable name => value pairs
-	* @return phpbb_template $this
-	*/
-	public function assign_block_vars($blockname, array $vararray)
-	{
-		$this->context->assign_block_vars($blockname, $vararray);
-
-		return $this;
-	}
-
-	/**
-	* Change already assigned key variable pair (one-dimensional - single loop entry)
-	*
-	* An example of how to use this function:
-	* {@example alter_block_array.php}
-	*
-	* @param	string	$blockname	the blockname, for example 'loop'
-	* @param	array	$vararray	the var array to insert/add or merge
-	* @param	mixed	$key		Key to search for
-	*
-	* array: KEY => VALUE [the key/value pair to search for within the loop to determine the correct position]
-	*
-	* int: Position [the position to change or insert at directly given]
-	*
-	* If key is false the position is set to 0
-	* If key is true the position is set to the last entry
-	*
-	* @param	string	$mode		Mode to execute (valid modes are 'insert' and 'change')
-	*
-	*	If insert, the vararray is inserted at the given position (position counting from zero).
-	*	If change, the current block gets merged with the vararray (resulting in new key/value pairs be added and existing keys be replaced by the new value).
-	*
-	* Since counting begins by zero, inserting at the last position will result in this array: array(vararray, last positioned array)
-	* and inserting at position 1 will result in this array: array(first positioned array, vararray, following vars)
-	*
-	* @return bool false on error, true on success
-	*/
-	public function alter_block_array($blockname, array $vararray, $key = false, $mode = 'insert')
-	{
-		return $this->context->alter_block_array($blockname, $vararray, $key, $mode);
-	}
-
-	/**
 	* Get template vars in a format Twig will use (from the context)
 	*
 	* @return array
 	*/
-	public function get_template_vars()
+	protected function get_template_vars()
 	{
 		$context_vars = $this->context->get_data_ref();
 
@@ -443,17 +330,6 @@ class phpbb_template_twig implements phpbb_template
 	}
 
 	/**
-	* Get a filename from the handle
-	*
-	* @param string $handle
-	* @return string
-	*/
-	protected function get_filename_from_handle($handle)
-	{
-		return (isset($this->filenames[$handle])) ? $this->filenames[$handle] : $handle;
-	}
-
-	/**
 	* Get path to template for handle (required for BBCode parser)
 	*
 	* @return string