commitall

vendor/ezyang/htmlpurifier/library/HTMLPurifier/AttrDef/CSS.php

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+<?php
+
+/**
+ * Validates the HTML attribute style, otherwise known as CSS.
+ * @note We don't implement the whole CSS specification, so it might be
+ *       difficult to reuse this component in the context of validating
+ *       actual stylesheet declarations.
+ * @note If we were really serious about validating the CSS, we would
+ *       tokenize the styles and then parse the tokens. Obviously, we
+ *       are not doing that. Doing that could seriously harm performance,
+ *       but would make these components a lot more viable for a CSS
+ *       filtering solution.
+ */
+class HTMLPurifier_AttrDef_CSS extends HTMLPurifier_AttrDef
+{
+
+    /**
+     * @param string $css
+     * @param HTMLPurifier_Config $config
+     * @param HTMLPurifier_Context $context
+     * @return bool|string
+     */
+    public function validate($css, $config, $context)
+    {
+        $css = $this->parseCDATA($css);
+
+        $definition = $config->getCSSDefinition();
+        $allow_duplicates = $config->get("CSS.AllowDuplicates");
+
+
+        // According to the CSS2.1 spec, the places where a
+        // non-delimiting semicolon can appear are in strings
+        // escape sequences.   So here is some dumb hack to
+        // handle quotes.
+        $len = strlen($css);
+        $accum = "";
+        $declarations = array();
+        $quoted = false;
+        for ($i = 0; $i < $len; $i++) {
+            $c = strcspn($css, ";'\"", $i);
+            $accum .= substr($css, $i, $c);
+            $i += $c;
+            if ($i == $len) break;
+            $d = $css[$i];
+            if ($quoted) {
+                $accum .= $d;
+                if ($d == $quoted) {
+                    $quoted = false;
+                }
+            } else {
+                if ($d == ";") {
+                    $declarations[] = $accum;
+                    $accum = "";
+                } else {
+                    $accum .= $d;
+                    $quoted = $d;
+                }
+            }
+        }
+        if ($accum != "") $declarations[] = $accum;
+
+        $propvalues = array();
+        $new_declarations = '';
+
+        /**
+         * Name of the current CSS property being validated.
+         */
+        $property = false;
+        $context->register('CurrentCSSProperty', $property);
+
+        foreach ($declarations as $declaration) {
+            if (!$declaration) {
+                continue;
+            }
+            if (!strpos($declaration, ':')) {
+                continue;
+            }
+            list($property, $value) = explode(':', $declaration, 2);
+            $property = trim($property);
+            $value = trim($value);
+            $ok = false;
+            do {
+                if (isset($definition->info[$property])) {
+                    $ok = true;
+                    break;
+                }
+                if (ctype_lower($property)) {
+                    break;
+                }
+                $property = strtolower($property);
+                if (isset($definition->info[$property])) {
+                    $ok = true;
+                    break;
+                }
+            } while (0);
+            if (!$ok) {
+                continue;
+            }
+            // inefficient call, since the validator will do this again
+            if (strtolower(trim($value)) !== 'inherit') {
+                // inherit works for everything (but only on the base property)
+                $result = $definition->info[$property]->validate(
+                    $value,
+                    $config,
+                    $context
+                );
+            } else {
+                $result = 'inherit';
+            }
+            if ($result === false) {
+                continue;
+            }
+            if ($allow_duplicates) {
+                $new_declarations .= "$property:$result;";
+            } else {
+                $propvalues[$property] = $result;
+            }
+        }
+
+        $context->destroy('CurrentCSSProperty');
+
+        // procedure does not write the new CSS simultaneously, so it's
+        // slightly inefficient, but it's the only way of getting rid of
+        // duplicates. Perhaps config to optimize it, but not now.
+
+        foreach ($propvalues as $prop => $value) {
+            $new_declarations .= "$prop:$value;";
+        }
+
+        return $new_declarations ? $new_declarations : false;
+
+    }
+
+}
+
+// vim: et sw=4 sts=4