mistpark 2.0 infrasturcture lands

1 files changed, 426 insertions, 0 deletions

diff --git a/library/HTMLPurifier/Encoder.php b/library/HTMLPurifier/Encoder.php
new file mode 100644
index 000000000..2b3140caa
--- /dev/null
+++ b/library/HTMLPurifier/Encoder.php
@@ -0,0 +1,426 @@
+<?php
+
+/**
+ * A UTF-8 specific character encoder that handles cleaning and transforming.
+ * @note All functions in this class should be static.
+ */
+class HTMLPurifier_Encoder
+{
+
+    /**
+     * Constructor throws fatal error if you attempt to instantiate class
+     */
+    private function __construct() {
+        trigger_error('Cannot instantiate encoder, call methods statically', E_USER_ERROR);
+    }
+
+    /**
+     * Error-handler that mutes errors, alternative to shut-up operator.
+     */
+    public static function muteErrorHandler() {}
+
+    /**
+     * 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.
+     *
+     * @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
+     *       respectively. 128 and above the code points map to multibyte
+     *       UTF-8 representations.
+     *
+     * @note Fallback 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, 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.
+     */
+    public static function cleanUTF8($str, $force_php = false) {
+
+        // UTF-8 validity is checked since PHP 4.3.5
+        // This is an optimization: if the string is already valid UTF-8, no
+        // need to do PHP stuff. 99% of the time, this will be the case.
+        // The regexp matches the XML char production, as well as well as excluding
+        // non-SGML codepoints U+007F to U+009F
+        if (preg_match('/^[\x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]*$/Du', $str)) {
+            return $str;
+        }
+
+        $mState = 0; // cached expected number of octets after the current octet
+                     // until the beginning of the next UTF8 character sequence
+        $mUcs4  = 0; // cached Unicode character
+        $mBytes = 1; // cached expected number of octets in the current sequence
+
+        // original code involved an $out that was an array of Unicode
+        // codepoints.  Instead of having to convert back into UTF-8, we've
+        // decided to directly append valid UTF-8 characters onto a string
+        // $out once they're done.  $char accumulates raw bytes, while $mUcs4
+        // turns into the Unicode code point, so there's some redundancy.
+
+        $out = '';
+        $char = '';
+
+        $len = strlen($str);
+        for($i = 0; $i < $len; $i++) {
+            $in = ord($str{$i});
+            $char .= $str[$i]; // append byte to char
+            if (0 == $mState) {
+                // When mState is zero we expect either a US-ASCII character
+                // or a multi-octet sequence.
+                if (0 == (0x80 & ($in))) {
+                    // US-ASCII, pass straight through.
+                    if (($in <= 31 || $in == 127) &&
+                        !($in == 9 || $in == 13 || $in == 10) // save \r\t\n
+                    ) {
+                        // control characters, remove
+                    } else {
+                        $out .= $char;
+                    }
+                    // reset
+                    $char = '';
+                    $mBytes = 1;
+                } elseif (0xC0 == (0xE0 & ($in))) {
+                    // First octet of 2 octet sequence
+                    $mUcs4 = ($in);
+                    $mUcs4 = ($mUcs4 & 0x1F) << 6;
+                    $mState = 1;
+                    $mBytes = 2;
+                } elseif (0xE0 == (0xF0 & ($in))) {
+                    // First octet of 3 octet sequence
+                    $mUcs4 = ($in);
+                    $mUcs4 = ($mUcs4 & 0x0F) << 12;
+                    $mState = 2;
+                    $mBytes = 3;
+                } elseif (0xF0 == (0xF8 & ($in))) {
+                    // First octet of 4 octet sequence
+                    $mUcs4 = ($in);
+                    $mUcs4 = ($mUcs4 & 0x07) << 18;
+                    $mState = 3;
+                    $mBytes = 4;
+                } elseif (0xF8 == (0xFC & ($in))) {
+                    // First octet of 5 octet sequence.
+                    //
+                    // This is illegal because the encoded codepoint must be
+                    // either:
+                    // (a) not the shortest form or
+                    // (b) outside the Unicode range of 0-0x10FFFF.
+                    // Rather than trying to resynchronize, we will carry on
+                    // until the end of the sequence and let the later error
+                    // handling code catch it.
+                    $mUcs4 = ($in);
+                    $mUcs4 = ($mUcs4 & 0x03) << 24;
+                    $mState = 4;
+                    $mBytes = 5;
+                } elseif (0xFC == (0xFE & ($in))) {
+                    // First octet of 6 octet sequence, see comments for 5
+                    // octet sequence.
+                    $mUcs4 = ($in);
+                    $mUcs4 = ($mUcs4 & 1) << 30;
+                    $mState = 5;
+                    $mBytes = 6;
+                } else {
+                    // Current octet is neither in the US-ASCII range nor a
+                    // legal first octet of a multi-octet sequence.
+                    $mState = 0;
+                    $mUcs4  = 0;
+                    $mBytes = 1;
+                    $char = '';
+                }
+            } else {
+                // When mState is non-zero, we expect a continuation of the
+                // multi-octet sequence
+                if (0x80 == (0xC0 & ($in))) {
+                    // Legal continuation.
+                    $shift = ($mState - 1) * 6;
+                    $tmp = $in;
+                    $tmp = ($tmp & 0x0000003F) << $shift;
+                    $mUcs4 |= $tmp;
+
+                    if (0 == --$mState) {
+                        // End of the multi-octet sequence. mUcs4 now contains
+                        // the final Unicode codepoint to be output
+
+                        // Check for illegal sequences and codepoints.
+
+                        // From Unicode 3.1, non-shortest form is illegal
+                        if (((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
+                            ((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
+                            ((4 == $mBytes) && ($mUcs4 < 0x10000)) ||
+                            (4 < $mBytes) ||
+                            // From Unicode 3.2, surrogate characters = illegal
+                            (($mUcs4 & 0xFFFFF800) == 0xD800) ||
+                            // Codepoints outside the Unicode range are illegal
+                            ($mUcs4 > 0x10FFFF)
+                        ) {
+
+                        } elseif (0xFEFF != $mUcs4 && // omit BOM
+                            // check for valid Char unicode codepoints
+                            (
+                                0x9 == $mUcs4 ||
+                                0xA == $mUcs4 ||
+                                0xD == $mUcs4 ||
+                                (0x20 <= $mUcs4 && 0x7E >= $mUcs4) ||
+                                // 7F-9F is not strictly prohibited by XML,
+                                // but it is non-SGML, and thus we don't allow it
+                                (0xA0 <= $mUcs4 && 0xD7FF >= $mUcs4) ||
+                                (0x10000 <= $mUcs4 && 0x10FFFF >= $mUcs4)
+                            )
+                        ) {
+                            $out .= $char;
+                        }
+                        // initialize UTF8 cache (reset)
+                        $mState = 0;
+                        $mUcs4  = 0;
+                        $mBytes = 1;
+                        $char = '';
+                    }
+                } else {
+                    // ((0xC0 & (*in) != 0x80) && (mState != 0))
+                    // Incomplete multi-octet sequence.
+                    // used to result in complete fail, but we'll reset
+                    $mState = 0;
+                    $mUcs4  = 0;
+                    $mBytes = 1;
+                    $char ='';
+                }
+            }
+        }
+        return $out;
+    }
+
+    /**
+     * Translates a Unicode codepoint into its corresponding UTF-8 character.
+     * @note Based on Feyd's function at
+     *       <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>,
+     *       which is in public domain.
+     * @note While we're going to do code point parsing anyway, a good
+     *       optimization would be to refuse to translate code points that
+     *       are non-SGML characters.  However, this could lead to duplication.
+     * @note This is very similar to the unichr function in
+     *       maintenance/generate-entity-file.php (although this is superior,
+     *       due to its sanity checks).
+     */
+
+    // +----------+----------+----------+----------+
+    // | 33222222 | 22221111 | 111111   |          |
+    // | 10987654 | 32109876 | 54321098 | 76543210 | bit
+    // +----------+----------+----------+----------+
+    // |          |          |          | 0xxxxxxx | 1 byte 0x00000000..0x0000007F
+    // |          |          | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF
+    // |          | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF
+    // | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF
+    // +----------+----------+----------+----------+
+    // | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF)
+    // | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes
+    // +----------+----------+----------+----------+
+
+    public static function unichr($code) {
+        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 $ret;
+    }
+
+    /**
+     * Converts a string to UTF-8 based on configuration.
+     */
+    public static function convertToUTF8($str, $config, $context) {
+        $encoding = $config->get('Core.Encoding');
+        if ($encoding === 'utf-8') return $str;
+        static $iconv = null;
+        if ($iconv === null) $iconv = function_exists('iconv');
+        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
+        if ($iconv && !$config->get('Test.ForceNoIconv')) {
+            $str = iconv($encoding, 'utf-8//IGNORE', $str);
+            if ($str === false) {
+                // $encoding is not a valid encoding
+                restore_error_handler();
+                trigger_error('Invalid encoding ' . $encoding, E_USER_ERROR);
+                return '';
+            }
+            // If the string is bjorked by Shift_JIS or a similar encoding
+            // that doesn't support all of ASCII, convert the naughty
+            // characters to their true byte-wise ASCII/UTF-8 equivalents.
+            $str = strtr($str, HTMLPurifier_Encoder::testEncodingSupportsASCII($encoding));
+            restore_error_handler();
+            return $str;
+        } elseif ($encoding === 'iso-8859-1') {
+            $str = utf8_encode($str);
+            restore_error_handler();
+            return $str;
+        }
+        trigger_error('Encoding not supported, please install iconv', E_USER_ERROR);
+    }
+
+    /**
+     * Converts a string from UTF-8 based on configuration.
+     * @note Currently, this is a lossy conversion, with unexpressable
+     *       characters being omitted.
+     */
+    public static function convertFromUTF8($str, $config, $context) {
+        $encoding = $config->get('Core.Encoding');
+        if ($encoding === 'utf-8') return $str;
+        static $iconv = null;
+        if ($iconv === null) $iconv = function_exists('iconv');
+        if ($escape = $config->get('Core.EscapeNonASCIICharacters')) {
+            $str = HTMLPurifier_Encoder::convertToASCIIDumbLossless($str);
+        }
+        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
+        if ($iconv && !$config->get('Test.ForceNoIconv')) {
+            // Undo our previous fix in convertToUTF8, otherwise iconv will barf
+            $ascii_fix = HTMLPurifier_Encoder::testEncodingSupportsASCII($encoding);
+            if (!$escape && !empty($ascii_fix)) {
+                $clear_fix = array();
+                foreach ($ascii_fix as $utf8 => $native) $clear_fix[$utf8] = '';
+                $str = strtr($str, $clear_fix);
+            }
+            $str = strtr($str, array_flip($ascii_fix));
+            // Normal stuff
+            $str = iconv('utf-8', $encoding . '//IGNORE', $str);
+            restore_error_handler();
+            return $str;
+        } elseif ($encoding === 'iso-8859-1') {
+            $str = utf8_decode($str);
+            restore_error_handler();
+            return $str;
+        }
+        trigger_error('Encoding not supported', E_USER_ERROR);
+    }
+
+    /**
+     * Lossless (character-wise) conversion of HTML to ASCII
+     * @param $str UTF-8 string to be converted to ASCII
+     * @returns ASCII encoded string with non-ASCII character entity-ized
+     * @warning Adapted from MediaWiki, claiming fair use: this is a common
+     *       algorithm. If you disagree with this license fudgery,
+     *       implement it yourself.
+     * @note Uses decimal numeric entities since they are best supported.
+     * @note This is a DUMB function: it has no concept of keeping
+     *       character entities that the projected character encoding
+     *       can allow. We could possibly implement a smart version
+     *       but that would require it to also know which Unicode
+     *       codepoints the charset supported (not an easy task).
+     * @note Sort of with cleanUTF8() but it assumes that $str is
+     *       well-formed UTF-8
+     */
+    public static function convertToASCIIDumbLossless($str) {
+        $bytesleft = 0;
+        $result = '';
+        $working = 0;
+        $len = strlen($str);
+        for( $i = 0; $i < $len; $i++ ) {
+            $bytevalue = ord( $str[$i] );
+            if( $bytevalue <= 0x7F ) { //0xxx xxxx
+                $result .= chr( $bytevalue );
+                $bytesleft = 0;
+            } elseif( $bytevalue <= 0xBF ) { //10xx xxxx
+                $working = $working << 6;
+                $working += ($bytevalue & 0x3F);
+                $bytesleft--;
+                if( $bytesleft <= 0 ) {
+                    $result .= "&#" . $working . ";";
+                }
+            } elseif( $bytevalue <= 0xDF ) { //110x xxxx
+                $working = $bytevalue & 0x1F;
+                $bytesleft = 1;
+            } elseif( $bytevalue <= 0xEF ) { //1110 xxxx
+                $working = $bytevalue & 0x0F;
+                $bytesleft = 2;
+            } else { //1111 0xxx
+                $working = $bytevalue & 0x07;
+                $bytesleft = 3;
+            }
+        }
+        return $result;
+    }
+
+    /**
+     * This expensive function tests whether or not a given character
+     * encoding supports ASCII. 7/8-bit encodings like Shift_JIS will
+     * fail this test, and require special processing. Variable width
+     * encodings shouldn't ever fail.
+     *
+     * @param string $encoding Encoding name to test, as per iconv format
+     * @param bool $bypass Whether or not to bypass the precompiled arrays.
+     * @return Array of UTF-8 characters to their corresponding ASCII,
+     *      which can be used to "undo" any overzealous iconv action.
+     */
+    public static function testEncodingSupportsASCII($encoding, $bypass = false) {
+        static $encodings = array();
+        if (!$bypass) {
+            if (isset($encodings[$encoding])) return $encodings[$encoding];
+            $lenc = strtolower($encoding);
+            switch ($lenc) {
+                case 'shift_jis':
+                    return array("\xC2\xA5" => '\\', "\xE2\x80\xBE" => '~');
+                case 'johab':
+                    return array("\xE2\x82\xA9" => '\\');
+            }
+            if (strpos($lenc, 'iso-8859-') === 0) return array();
+        }
+        $ret = array();
+        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
+        if (iconv('UTF-8', $encoding, 'a') === false) return false;
+        for ($i = 0x20; $i <= 0x7E; $i++) { // all printable ASCII chars
+            $c = chr($i); // UTF-8 char
+            $r = iconv('UTF-8', "$encoding//IGNORE", $c); // initial conversion
+            if (
+                $r === '' ||
+                // This line is needed for iconv implementations that do not
+                // omit characters that do not exist in the target character set
+                ($r === $c && iconv($encoding, 'UTF-8//IGNORE', $r) !== $c)
+            ) {
+                // Reverse engineer: what's the UTF-8 equiv of this byte
+                // sequence? This assumes that there's no variable width
+                // encoding that doesn't support ASCII.
+                $ret[iconv($encoding, 'UTF-8//IGNORE', $c)] = $c;
+            }
+        }
+        restore_error_handler();
+        $encodings[$encoding] = $ret;
+        return $ret;
+    }
+
+
+}
+
+// vim: et sw=4 sts=4