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More refactoring: bundling charset and entity stuff together makes little sense, so new HTMLPurifier/EntityParser.php.

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git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@341 48356398-32a2-884e-a903-53898d9a118a
This commit is contained in:
Edward Z. Yang
2006-08-30 02:21:39 +00:00
parent 89376a11e3
commit 0ac97774d4
7 changed files with 309 additions and 259 deletions
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207
library/HTMLPurifier/Encoder.php
View File

@@ -3,164 +3,17 @@
require_once 'HTMLPurifier/EntityLookup.php';
/**
* An HTML and UTF-8 specific encoder that cleans, unentity-izes and transforms.
* A UTF-8 specific character encoder that handles cleaning and transforming.
*/
class HTMLPurifier_Encoder
{
var $_entity_lookup;
/**
* Callback regex string for parsing entities.
* @protected
*/
var $_substituteEntitiesRegex =
'/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z]+));?/';
// 1. hex 2. dec 3. string
/**
* Decimal to parsed string conversion table for special entities.
* @protected
*/
var $_special_dec2str =
array(
34 => '"',
38 => '&',
39 => "'",
60 => '<',
62 => '>'
);
/**
* Stripped entity names to decimal conversion table for special entities.
* @protected
*/
var $_special_ent2dec =
array(
'quot' => 34,
'amp' => 38,
'lt' => 60,
'gt' => 62
);
/**
* Substitutes non-special entities with their parsed equivalents. Since
* running this whenever you have parsed character is t3h 5uck, we run
* it before everything else.
*
* @protected
* @param $string String to have non-special entities parsed.
* @returns Parsed string.
*/
function substituteNonSpecialEntities($string) {
// it will try to detect missing semicolons, but don't rely on it
return preg_replace_callback(
$this->_substituteEntitiesRegex,
array($this, 'nonSpecialEntityCallback'),
$string
);
}
/**
* Callback function for substituteNonSpecialEntities() that does the work.
*
* @warning Though this is public in order to let the callback happen,
* calling it directly is not recommended.
* @note Based on Feyd's function at
* <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>,
* which is in public domain.
* @note While we're going to do code point parsing anyway, a good
* optimization would be to refuse to translate code points that
* are non-SGML characters. However, this could lead to duplication.
* @param $matches PCRE matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @returns Replacement string.
* @todo Implement string translations
*/
// +----------+----------+----------+----------+
// | 33222222 | 22221111 | 111111 | |
// | 10987654 | 32109876 | 54321098 | 76543210 | bit
// +----------+----------+----------+----------+
// | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F
// | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF
// | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF
// | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF
// +----------+----------+----------+----------+
// | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF)
// | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes
// +----------+----------+----------+----------+
function nonSpecialEntityCallback($matches) {
// replaces all but big five
$entity = $matches[0];
$is_num = (@$matches[0][1] === '#');
if ($is_num) {
$is_hex = (@$entity[2] === 'x');
$code = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
// abort for special characters
if (isset($this->_special_dec2str[$code])) return $entity;
if($code > 1114111 or $code < 0 or
($code >= 55296 and $code <= 57343) ) {
// bits are set outside the "valid" range as defined
// by UNICODE 4.1.0
return '';
}
$x = $y = $z = $w = 0;
if ($code < 128) {
// regular ASCII character
$x = $code;
} else {
// set up bits for UTF-8
$x = ($code & 63) | 128;
if ($code < 2048) {
$y = (($code & 2047) >> 6) | 192;
} else {
$y = (($code & 4032) >> 6) | 128;
if($code < 65536) {
$z = (($code >> 12) & 15) | 224;
} else {
$z = (($code >> 12) & 63) | 128;
$w = (($code >> 18) & 7) | 240;
}
}
}
// set up the actual character
$ret = '';
if($w) $ret .= chr($w);
if($z) $ret .= chr($z);
if($y) $ret .= chr($y);
$ret .= chr($x);
return $ret;
} else {
if (isset($this->_special_ent2dec[$matches[3]])) return $entity;
if (!$this->_entity_lookup) {
require_once 'HTMLPurifier/EntityLookup.php';
$this->_entity_lookup = HTMLPurifier_EntityLookup::instance();
}
if (isset($this->_entity_lookup->table[$matches[3]])) {
return $this->_entity_lookup->table[$matches[3]];
} else {
return $entity;
}
}
}
/**
* Cleans a UTF-8 string for well-formedness and SGML validity
*
* It will parse according to UTF-8 and return a valid UTF8 string, with
* non-SGML codepoints excluded.
*
* @warning This function can find a lot of use, so we may be moving
* it to a dedicated class.
*
* @note Just for reference, the non-SGML code points are 0 to 31 and
* 127 to 159, inclusive. However, we allow code points 9, 10
* and 13, which are the tab, line feed and carriage return
@@ -171,7 +24,8 @@ class HTMLPurifier_Encoder
* implemented with iconv using 'UTF-8//IGNORE', mbstring, or
* even the PCRE modifier 'u', these do not allow us to strip
* control characters or disallowed code points, and the latter
* does not allow invalid UTF8 characters to be ignored.
* does not allow invalid UTF-8 characters to be ignored. Once
* PHP 6 appears all our problems magically disappear.
*
* @note Decomposing the string into Unicode code points is necessary
* because SGML disallows the use of specific code points, not
@@ -181,7 +35,16 @@ class HTMLPurifier_Encoder
*
* @note Code adapted from utf8ToUnicode by Henri Sivonen and
* hsivonen@iki.fi at <http://iki.fi/hsivonen/php-utf8/> under the
* LGPL license. Notes on what changed are inside.
* LGPL license. Notes on what changed are inside, but in general,
* the original code transformed UTF-8 text into an array of integer
* Unicode codepoints. Understandably, transforming that back to
* a string would be somewhat expensive, so the function was modded to
* directly operate on the string. However, this discourages code
* reuse, and the logic enumerated here would be useful for any
* function that needs to be able to understand UTF-8 characters.
* As of right now, only smart lossless character encoding converters
* would need that, and I'm probably not going to implement them.
* Once again, PHP 6 should solve all our problems.
*/
function cleanUTF8($str) {
$mState = 0; // cached expected number of octets after the current octet
@@ -316,50 +179,6 @@ class HTMLPurifier_Encoder
return $out;
}
/**
* Substitutes only special entities with their parsed equivalents.
*
* @notice We try to avoid calling this function because otherwise, it
* would have to be called a lot (for every parsed section).
*
* @protected
* @param $string String to have non-special entities parsed.
* @returns Parsed string.
*/
function substituteSpecialEntities($string) {
return preg_replace_callback(
$this->_substituteEntitiesRegex,
array('HTMLPurifier_Encoder', 'specialEntityCallback'),
$string);
}
/**
* Callback function for substituteSpecialEntities() that does the work.
*
* This callback has same syntax as nonSpecialEntityCallback().
*
* @warning Though this is public in order to let the callback happen,
* calling it directly is not recommended.
* @param $matches PCRE-style matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @returns Replacement string.
*/
function specialEntityCallback($matches) {
$entity = $matches[0];
$is_num = (@$matches[0][1] === '#');
if ($is_num) {
$is_hex = (@$entity[2] === 'x');
$int = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
return isset($this->_special_dec2str[$int]) ?
$this->_special_dec2str[$int] :
$entity;
} else {
return isset($this->_special_ent2dec[$matches[3]]) ?
$this->_special_ent2dec[$matches[3]] :
$entity;
}
}
}

212
library/HTMLPurifier/EntityParser.php Normal file
View File

@@ -0,0 +1,212 @@
<?php
require_once 'HTMLPurifier/EntityLookup.php';
/**
* Handles referencing and derefencing character entities
*/
class HTMLPurifier_EntityParser
{
/**
* Reference to entity lookup talbe.
* @protected
*/
var $_entity_lookup;
/**
* Callback regex string for parsing entities.
* @protected
*/
var $_substituteEntitiesRegex =
'/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z]+));?/';
// 1. hex 2. dec 3. string
/**
* Decimal to parsed string conversion table for special entities.
* @protected
*/
var $_special_dec2str =
array(
34 => '"',
38 => '&',
39 => "'",
60 => '<',
62 => '>'
);
/**
* Stripped entity names to decimal conversion table for special entities.
* @protected
*/
var $_special_ent2dec =
array(
'quot' => 34,
'amp' => 38,
'lt' => 60,
'gt' => 62
);
/**
* Substitutes non-special entities with their parsed equivalents. Since
* running this whenever you have parsed character is t3h 5uck, we run
* it before everything else.
*
* @protected
* @param $string String to have non-special entities parsed.
* @returns Parsed string.
*/
function substituteNonSpecialEntities($string) {
// it will try to detect missing semicolons, but don't rely on it
return preg_replace_callback(
$this->_substituteEntitiesRegex,
array($this, 'nonSpecialEntityCallback'),
$string
);
}
/**
* Callback function for substituteNonSpecialEntities() that does the work.
*
* @warning Though this is public in order to let the callback happen,
* calling it directly is not recommended.
* @note Based on Feyd's function at
* <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>,
* which is in public domain.
* @note While we're going to do code point parsing anyway, a good
* optimization would be to refuse to translate code points that
* are non-SGML characters. However, this could lead to duplication.
* @note This function is heavily intimate with the inner workings of
* UTF-8 and would also be well suited in the Encoder class (or at
* least deferring some processing to it). This is also very
* similar to the unichr function in
* maintenance/generate-entity-file.php (although this is superior,
* due to its sanity checks).
* @param $matches PCRE matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @returns Replacement string.
* @todo Implement string translations
*/
// +----------+----------+----------+----------+
// | 33222222 | 22221111 | 111111 | |
// | 10987654 | 32109876 | 54321098 | 76543210 | bit
// +----------+----------+----------+----------+
// | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F
// | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF
// | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF
// | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF
// +----------+----------+----------+----------+
// | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF)
// | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes
// +----------+----------+----------+----------+
function nonSpecialEntityCallback($matches) {
// replaces all but big five
$entity = $matches[0];
$is_num = (@$matches[0][1] === '#');
if ($is_num) {
$is_hex = (@$entity[2] === 'x');
$code = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
// abort for special characters
if (isset($this->_special_dec2str[$code])) return $entity;
if($code > 1114111 or $code < 0 or
($code >= 55296 and $code <= 57343) ) {
// bits are set outside the "valid" range as defined
// by UNICODE 4.1.0
return '';
}
$x = $y = $z = $w = 0;
if ($code < 128) {
// regular ASCII character
$x = $code;
} else {
// set up bits for UTF-8
$x = ($code & 63) | 128;
if ($code < 2048) {
$y = (($code & 2047) >> 6) | 192;
} else {
$y = (($code & 4032) >> 6) | 128;
if($code < 65536) {
$z = (($code >> 12) & 15) | 224;
} else {
$z = (($code >> 12) & 63) | 128;
$w = (($code >> 18) & 7) | 240;
}
}
}
// set up the actual character
$ret = '';
if($w) $ret .= chr($w);
if($z) $ret .= chr($z);
if($y) $ret .= chr($y);
$ret .= chr($x);
return $ret;
} else {
if (isset($this->_special_ent2dec[$matches[3]])) return $entity;
if (!$this->_entity_lookup) {
require_once 'HTMLPurifier/EntityLookup.php';
$this->_entity_lookup = HTMLPurifier_EntityLookup::instance();
}
if (isset($this->_entity_lookup->table[$matches[3]])) {
return $this->_entity_lookup->table[$matches[3]];
} else {
return $entity;
}
}
}
/**
* Substitutes only special entities with their parsed equivalents.
*
* @notice We try to avoid calling this function because otherwise, it
* would have to be called a lot (for every parsed section).
*
* @protected
* @param $string String to have non-special entities parsed.
* @returns Parsed string.
*/
function substituteSpecialEntities($string) {
return preg_replace_callback(
$this->_substituteEntitiesRegex,
array($this, 'specialEntityCallback'),
$string);
}
/**
* Callback function for substituteSpecialEntities() that does the work.
*
* This callback has same syntax as nonSpecialEntityCallback().
*
* @warning Though this is public in order to let the callback happen,
* calling it directly is not recommended.
* @param $matches PCRE-style matches array, with 0 the entire match, and
* either index 1, 2 or 3 set with a hex value, dec value,
* or string (respectively).
* @returns Replacement string.
*/
function specialEntityCallback($matches) {
$entity = $matches[0];
$is_num = (@$matches[0][1] === '#');
if ($is_num) {
$is_hex = (@$entity[2] === 'x');
$int = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
return isset($this->_special_dec2str[$int]) ?
$this->_special_dec2str[$int] :
$entity;
} else {
return isset($this->_special_ent2dec[$matches[3]]) ?
$this->_special_ent2dec[$matches[3]] :
$entity;
}
}
}
?>

4
library/HTMLPurifier/Lexer.php
View File

@@ -2,6 +2,7 @@
require_once 'HTMLPurifier/Token.php';
require_once 'HTMLPurifier/Encoder.php';
require_once 'HTMLPurifier/EntityParser.php';
HTMLPurifier_ConfigDef::define(
'Core', 'AcceptFullDocuments', true, 'bool',
@@ -57,6 +58,7 @@ class HTMLPurifier_Lexer
function HTMLPurifier_Lexer() {
$this->_encoder = new HTMLPurifier_Encoder();
$this->_entity_parser = new HTMLPurifier_EntityParser();
}
var $_encoder;
@@ -152,7 +154,7 @@ class HTMLPurifier_Lexer
$html = $this->escapeCDATA($html);
// expand entities that aren't the big five
$html = $this->_encoder->substituteNonSpecialEntities($html);
$html = $this->_entity_parser->substituteNonSpecialEntities($html);
// clean into wellformed UTF-8 string for an SGML context: this has
// to be done after entity expansion because the entities sometimes

2
library/HTMLPurifier/Lexer/DirectLex.php
View File

@@ -66,7 +66,7 @@ class HTMLPurifier_Lexer_DirectLex extends HTMLPurifier_Lexer
if ($num_amp_2 <= $num_esc_amp) return $string;
// hmm... now we have some uncommon entities. Use the callback.
$string = $this->_encoder->substituteSpecialEntities($string);
$string = $this->_entity_parser->substituteSpecialEntities($string);
return $string;
}