1 files changed, 114 insertions, 0 deletions
diff --git a/library/HTMLPurifier/URIFilter/MakeAbsolute.php b/library/HTMLPurifier/URIFilter/MakeAbsolute.php
new file mode 100644
index 000000000..f46ab2630
--- /dev/null
+++ b/library/HTMLPurifier/URIFilter/MakeAbsolute.php
@@ -0,0 +1,114 @@
+<?php
+
+// does not support network paths
+
+class HTMLPurifier_URIFilter_MakeAbsolute extends HTMLPurifier_URIFilter
+{
+    public $name = 'MakeAbsolute';
+    protected $base;
+    protected $basePathStack = array();
+    public function prepare($config) {
+        $def = $config->getDefinition('URI');
+        $this->base = $def->base;
+        if (is_null($this->base)) {
+            trigger_error('URI.MakeAbsolute is being ignored due to lack of value for URI.Base configuration', E_USER_WARNING);
+            return false;
+        }
+        $this->base->fragment = null; // fragment is invalid for base URI
+        $stack = explode('/', $this->base->path);
+        array_pop($stack); // discard last segment
+        $stack = $this->_collapseStack($stack); // do pre-parsing
+        $this->basePathStack = $stack;
+        return true;
+    }
+    public function filter(&$uri, $config, $context) {
+        if (is_null($this->base)) return true; // abort early
+        if (
+            $uri->path === '' && is_null($uri->scheme) &&
+            is_null($uri->host) && is_null($uri->query) && is_null($uri->fragment)
+        ) {
+            // reference to current document
+            $uri = clone $this->base;
+            return true;
+        }
+        if (!is_null($uri->scheme)) {
+            // absolute URI already: don't change
+            if (!is_null($uri->host)) return true;
+            $scheme_obj = $uri->getSchemeObj($config, $context);
+            if (!$scheme_obj) {
+                // scheme not recognized
+                return false;
+            }
+            if (!$scheme_obj->hierarchical) {
+                // non-hierarchal URI with explicit scheme, don't change
+                return true;
+            }
+            // special case: had a scheme but always is hierarchical and had no authority
+        }
+        if (!is_null($uri->host)) {
+            // network path, don't bother
+            return true;
+        }
+        if ($uri->path === '') {
+            $uri->path = $this->base->path;
+        } elseif ($uri->path[0] !== '/') {
+            // relative path, needs more complicated processing
+            $stack = explode('/', $uri->path);
+            $new_stack = array_merge($this->basePathStack, $stack);
+            if ($new_stack[0] !== '' && !is_null($this->base->host)) {
+                array_unshift($new_stack, '');
+            }
+            $new_stack = $this->_collapseStack($new_stack);
+            $uri->path = implode('/', $new_stack);
+        } else {
+            // absolute path, but still we should collapse
+            $uri->path = implode('/', $this->_collapseStack(explode('/', $uri->path)));
+        }
+        // re-combine
+        $uri->scheme = $this->base->scheme;
+        if (is_null($uri->userinfo)) $uri->userinfo = $this->base->userinfo;
+        if (is_null($uri->host))     $uri->host     = $this->base->host;
+        if (is_null($uri->port))     $uri->port     = $this->base->port;
+        return true;
+    }
+
+    /**
+     * Resolve dots and double-dots in a path stack
+     */
+    private function _collapseStack($stack) {
+        $result = array();
+        $is_folder = false;
+        for ($i = 0; isset($stack[$i]); $i++) {
+            $is_folder = false;
+            // absorb an internally duplicated slash
+            if ($stack[$i] == '' && $i && isset($stack[$i+1])) continue;
+            if ($stack[$i] == '..') {
+                if (!empty($result)) {
+                    $segment = array_pop($result);
+                    if ($segment === '' && empty($result)) {
+                        // error case: attempted to back out too far:
+                        // restore the leading slash
+                        $result[] = '';
+                    } elseif ($segment === '..') {
+                        $result[] = '..'; // cannot remove .. with ..
+                    }
+                } else {
+                    // relative path, preserve the double-dots
+                    $result[] = '..';
+                }
+                $is_folder = true;
+                continue;
+            }
+            if ($stack[$i] == '.') {
+                // silently absorb
+                $is_folder = true;
+                continue;
+            }
+            $result[] = $stack[$i];
+        }
+        if ($is_folder) $result[] = '';
+        return $result;
+    }
+}
+
+// vim: et sw=4 sts=4