library/HTMLPurifier/ConfigSchema/Validator.php

   1 <?php
   2
   3 /**
   4  * Performs validations on HTMLPurifier_ConfigSchema_Interchange
   5  *
   6  * @note If you see '// handled by InterchangeBuilder', that means a
   7  *       design decision in that class would prevent this validation from
   8  *       ever being necessary. We have them anyway, however, for
   9  *       redundancy.
  10  */
  11 class HTMLPurifier_ConfigSchema_Validator
  12 {
  13
  14     /**
  15      * Easy to access global objects.
  16      */
  17     protected $interchange, $aliases;
  18
  19     /**
  20      * Context-stack to provide easy to read error messages.
  21      */
  22     protected $context = array();
  23
  24     /**
  25      * HTMLPurifier_VarParser to test default's type.
  26      */
  27     protected $parser;
  28
  29     public function __construct() {
  30         $this->parser = new HTMLPurifier_VarParser();
  31     }
  32
  33     /**
  34      * Validates a fully-formed interchange object. Throws an
  35      * HTMLPurifier_ConfigSchema_Exception if there's a problem.
  36      */
  37     public function validate($interchange) {
  38         $this->interchange = $interchange;
  39         $this->aliases = array();
  40         // PHP is a bit lax with integer <=> string conversions in
  41         // arrays, so we don't use the identical !== comparison
  42         foreach ($interchange->namespaces as $i => $namespace) {
  43             if ($i != $namespace->namespace) $this->error(false, "Integrity violation: key '$i' does not match internal id '{$namespace->namespace}'");
  44             $this->validateNamespace($namespace);
  45         }
  46         foreach ($interchange->directives as $i => $directive) {
  47             $id = $directive->id->toString();
  48             if ($i != $id) $this->error(false, "Integrity violation: key '$i' does not match internal id '$id'");
  49             $this->validateDirective($directive);
  50         }
  51         return true;
  52     }
  53
  54     /**
  55      * Validates a HTMLPurifier_ConfigSchema_Interchange_Namespace object.
  56      */
  57     public function validateNamespace($n) {
  58         $this->context[] = "namespace '{$n->namespace}'";
  59         $this->with($n, 'namespace')
  60             ->assertNotEmpty()
  61             ->assertAlnum(); // implicit assertIsString handled by InterchangeBuilder
  62         $this->with($n, 'description')
  63             ->assertNotEmpty()
  64             ->assertIsString(); // handled by InterchangeBuilder
  65         array_pop($this->context);
  66     }
  67
  68     /**
  69      * Validates a HTMLPurifier_ConfigSchema_Interchange_Id object.
  70      */
  71     public function validateId($id) {
  72         $id_string = $id->toString();
  73         $this->context[] = "id '$id_string'";
  74         if (!$id instanceof HTMLPurifier_ConfigSchema_Interchange_Id) {
  75             // handled by InterchangeBuilder
  76             $this->error(false, 'is not an instance of HTMLPurifier_ConfigSchema_Interchange_Id');
  77         }
  78         if (!isset($this->interchange->namespaces[$id->namespace])) {
  79             $this->error('namespace', 'does not exist'); // assumes that the namespace was validated already
  80         }
  81         $this->with($id, 'directive')
  82             ->assertNotEmpty()
  83             ->assertAlnum(); // implicit assertIsString handled by InterchangeBuilder
  84         array_pop($this->context);
  85     }
  86
  87     /**
  88      * Validates a HTMLPurifier_ConfigSchema_Interchange_Directive object.
  89      */
  90     public function validateDirective($d) {
  91         $id = $d->id->toString();
  92         $this->context[] = "directive '$id'";
  93         $this->validateId($d->id);
  94
  95         $this->with($d, 'description')
  96             ->assertNotEmpty();
  97
  98         // BEGIN - handled by InterchangeBuilder
  99         $this->with($d, 'type')
 100             ->assertNotEmpty();
 101         $this->with($d, 'typeAllowsNull')
 102             ->assertIsBool();
 103         try {
 104             // This also tests validity of $d->type
 105             $this->parser->parse($d->default, $d->type, $d->typeAllowsNull);
 106         } catch (HTMLPurifier_VarParserException $e) {
 107             $this->error('default', 'had error: ' . $e->getMessage());
 108         }
 109         // END - handled by InterchangeBuilder
 110
 111         if (!is_null($d->allowed) || !empty($d->valueAliases)) {
 112             // allowed and valueAliases require that we be dealing with
 113             // strings, so check for that early.
 114             $d_int = HTMLPurifier_VarParser::$types[$d->type];
 115             if (!isset(HTMLPurifier_VarParser::$stringTypes[$d_int])) {
 116                 $this->error('type', 'must be a string type when used with allowed or value aliases');
 117             }
 118         }
 119
 120         $this->validateDirectiveAllowed($d);
 121         $this->validateDirectiveValueAliases($d);
 122         $this->validateDirectiveAliases($d);
 123
 124         array_pop($this->context);
 125     }
 126
 127     /**
 128      * Extra validation if $allowed member variable of
 129      * HTMLPurifier_ConfigSchema_Interchange_Directive is defined.
 130      */
 131     public function validateDirectiveAllowed($d) {
 132         if (is_null($d->allowed)) return;
 133         $this->with($d, 'allowed')
 134             ->assertNotEmpty()
 135             ->assertIsLookup(); // handled by InterchangeBuilder
 136         if (is_string($d->default) && !isset($d->allowed[$d->default])) {
 137             $this->error('default', 'must be an allowed value');
 138         }
 139         $this->context[] = 'allowed';
 140         foreach ($d->allowed as $val => $x) {
 141             if (!is_string($val)) $this->error("value $val", 'must be a string');
 142         }
 143         array_pop($this->context);
 144     }
 145
 146     /**
 147      * Extra validation if $valueAliases member variable of
 148      * HTMLPurifier_ConfigSchema_Interchange_Directive is defined.
 149      */
 150     public function validateDirectiveValueAliases($d) {
 151         if (is_null($d->valueAliases)) return;
 152         $this->with($d, 'valueAliases')
 153             ->assertIsArray(); // handled by InterchangeBuilder
 154         $this->context[] = 'valueAliases';
 155         foreach ($d->valueAliases as $alias => $real) {
 156             if (!is_string($alias)) $this->error("alias $alias", 'must be a string');
 157             if (!is_string($real))  $this->error("alias target $real from alias '$alias'",  'must be a string');
 158             if ($alias === $real) {
 159                 $this->error("alias '$alias'", "must not be an alias to itself");
 160             }
 161         }
 162         if (!is_null($d->allowed)) {
 163             foreach ($d->valueAliases as $alias => $real) {
 164                 if (isset($d->allowed[$alias])) {
 165                     $this->error("alias '$alias'", 'must not be an allowed value');
 166                 } elseif (!isset($d->allowed[$real])) {
 167                     $this->error("alias '$alias'", 'must be an alias to an allowed value');
 168                 }
 169             }
 170         }
 171         array_pop($this->context);
 172     }
 173
 174     /**
 175      * Extra validation if $aliases member variable of
 176      * HTMLPurifier_ConfigSchema_Interchange_Directive is defined.
 177      */
 178     public function validateDirectiveAliases($d) {
 179         $this->with($d, 'aliases')
 180             ->assertIsArray(); // handled by InterchangeBuilder
 181         $this->context[] = 'aliases';
 182         foreach ($d->aliases as $alias) {
 183             $this->validateId($alias);
 184             $s = $alias->toString();
 185             if (isset($this->interchange->directives[$s])) {
 186                 $this->error("alias '$s'", 'collides with another directive');
 187             }
 188             if (isset($this->aliases[$s])) {
 189                 $other_directive = $this->aliases[$s];
 190                 $this->error("alias '$s'", "collides with alias for directive '$other_directive'");
 191             }
 192             $this->aliases[$s] = $d->id->toString();
 193         }
 194         array_pop($this->context);
 195     }
 196
 197     // protected helper functions
 198
 199     /**
 200      * Convenience function for generating HTMLPurifier_ConfigSchema_ValidatorAtom
 201      * for validating simple member variables of objects.
 202      */
 203     protected function with($obj, $member) {
 204         return new HTMLPurifier_ConfigSchema_ValidatorAtom($this->getFormattedContext(), $obj, $member);
 205     }
 206
 207     /**
 208      * Emits an error, providing helpful context.
 209      */
 210     protected function error($target, $msg) {
 211         if ($target !== false) $prefix = ucfirst($target) . ' in ' .  $this->getFormattedContext();
 212         else $prefix = ucfirst($this->getFormattedContext());
 213         throw new HTMLPurifier_ConfigSchema_Exception(trim($prefix . ' ' . $msg));
 214     }
 215
 216     /**
 217      * Returns a formatted context string.
 218      */
 219     protected function getFormattedContext() {
 220         return implode(' in ', array_reverse($this->context));
 221     }
 222
 223 }
 224
 225 // vim: et sw=4 sts=4