WordPress/wp-includes/compat.php
Gary Pendergast bd45c7d3b9 Code Modernisation: Document when the Hash polyfills can be removed.
The Hash extension cannot be disabled as of PHP 7.4. So, while we can't remove these polyfills yet, we can document when we'll be able to.

Props jrf.
Fixes #47698.


Built from https://develop.svn.wordpress.org/trunk@45638


git-svn-id: http://core.svn.wordpress.org/trunk@45449 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2019-07-15 05:14:55 +00:00

503 lines
15 KiB
PHP

<?php
/**
* WordPress implementation for PHP functions either missing from older PHP versions or not included by default.
*
* @package PHP
* @access private
*/
// If gettext isn't available
if ( ! function_exists( '_' ) ) {
function _( $string ) {
return $string;
}
}
/**
* Returns whether PCRE/u (PCRE_UTF8 modifier) is available for use.
*
* @ignore
* @since 4.2.2
* @access private
*
* @staticvar string $utf8_pcre
*
* @param bool $set - Used for testing only
* null : default - get PCRE/u capability
* false : Used for testing - return false for future calls to this function
* 'reset': Used for testing - restore default behavior of this function
*/
function _wp_can_use_pcre_u( $set = null ) {
static $utf8_pcre = 'reset';
if ( null !== $set ) {
$utf8_pcre = $set;
}
if ( 'reset' === $utf8_pcre ) {
// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- intentional error generated to detect PCRE/u support.
$utf8_pcre = @preg_match( '/^./u', 'a' );
}
return $utf8_pcre;
}
if ( ! function_exists( 'mb_substr' ) ) :
/**
* Compat function to mimic mb_substr().
*
* @ignore
* @since 3.2.0
*
* @see _mb_substr()
*
* @param string $str The string to extract the substring from.
* @param int $start Position to being extraction from in `$str`.
* @param int|null $length Optional. Maximum number of characters to extract from `$str`.
* Default null.
* @param string|null $encoding Optional. Character encoding to use. Default null.
* @return string Extracted substring.
*/
function mb_substr( $str, $start, $length = null, $encoding = null ) {
return _mb_substr( $str, $start, $length, $encoding );
}
endif;
/**
* Internal compat function to mimic mb_substr().
*
* Only understands UTF-8 and 8bit. All other character sets will be treated as 8bit.
* For $encoding === UTF-8, the $str input is expected to be a valid UTF-8 byte sequence.
* The behavior of this function for invalid inputs is undefined.
*
* @ignore
* @since 3.2.0
*
* @param string $str The string to extract the substring from.
* @param int $start Position to being extraction from in `$str`.
* @param int|null $length Optional. Maximum number of characters to extract from `$str`.
* Default null.
* @param string|null $encoding Optional. Character encoding to use. Default null.
* @return string Extracted substring.
*/
function _mb_substr( $str, $start, $length = null, $encoding = null ) {
if ( null === $encoding ) {
$encoding = get_option( 'blog_charset' );
}
/*
* The solution below works only for UTF-8, so in case of a different
* charset just use built-in substr().
*/
if ( ! in_array( $encoding, array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ) ) ) {
return is_null( $length ) ? substr( $str, $start ) : substr( $str, $start, $length );
}
if ( _wp_can_use_pcre_u() ) {
// Use the regex unicode support to separate the UTF-8 characters into an array.
preg_match_all( '/./us', $str, $match );
$chars = is_null( $length ) ? array_slice( $match[0], $start ) : array_slice( $match[0], $start, $length );
return implode( '', $chars );
}
$regex = '/(
[\x00-\x7F] # single-byte sequences 0xxxxxxx
| [\xC2-\xDF][\x80-\xBF] # double-byte sequences 110xxxxx 10xxxxxx
| \xE0[\xA0-\xBF][\x80-\xBF] # triple-byte sequences 1110xxxx 10xxxxxx * 2
| [\xE1-\xEC][\x80-\xBF]{2}
| \xED[\x80-\x9F][\x80-\xBF]
| [\xEE-\xEF][\x80-\xBF]{2}
| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences 11110xxx 10xxxxxx * 3
| [\xF1-\xF3][\x80-\xBF]{3}
| \xF4[\x80-\x8F][\x80-\xBF]{2}
)/x';
// Start with 1 element instead of 0 since the first thing we do is pop.
$chars = array( '' );
do {
// We had some string left over from the last round, but we counted it in that last round.
array_pop( $chars );
/*
* Split by UTF-8 character, limit to 1000 characters (last array element will contain
* the rest of the string).
*/
$pieces = preg_split( $regex, $str, 1000, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY );
$chars = array_merge( $chars, $pieces );
// If there's anything left over, repeat the loop.
} while ( count( $pieces ) > 1 && $str = array_pop( $pieces ) );
return join( '', array_slice( $chars, $start, $length ) );
}
if ( ! function_exists( 'mb_strlen' ) ) :
/**
* Compat function to mimic mb_strlen().
*
* @ignore
* @since 4.2.0
*
* @see _mb_strlen()
*
* @param string $str The string to retrieve the character length from.
* @param string|null $encoding Optional. Character encoding to use. Default null.
* @return int String length of `$str`.
*/
function mb_strlen( $str, $encoding = null ) {
return _mb_strlen( $str, $encoding );
}
endif;
/**
* Internal compat function to mimic mb_strlen().
*
* Only understands UTF-8 and 8bit. All other character sets will be treated as 8bit.
* For $encoding === UTF-8, the `$str` input is expected to be a valid UTF-8 byte
* sequence. The behavior of this function for invalid inputs is undefined.
*
* @ignore
* @since 4.2.0
*
* @param string $str The string to retrieve the character length from.
* @param string|null $encoding Optional. Character encoding to use. Default null.
* @return int String length of `$str`.
*/
function _mb_strlen( $str, $encoding = null ) {
if ( null === $encoding ) {
$encoding = get_option( 'blog_charset' );
}
/*
* The solution below works only for UTF-8, so in case of a different charset
* just use built-in strlen().
*/
if ( ! in_array( $encoding, array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ) ) ) {
return strlen( $str );
}
if ( _wp_can_use_pcre_u() ) {
// Use the regex unicode support to separate the UTF-8 characters into an array.
preg_match_all( '/./us', $str, $match );
return count( $match[0] );
}
$regex = '/(?:
[\x00-\x7F] # single-byte sequences 0xxxxxxx
| [\xC2-\xDF][\x80-\xBF] # double-byte sequences 110xxxxx 10xxxxxx
| \xE0[\xA0-\xBF][\x80-\xBF] # triple-byte sequences 1110xxxx 10xxxxxx * 2
| [\xE1-\xEC][\x80-\xBF]{2}
| \xED[\x80-\x9F][\x80-\xBF]
| [\xEE-\xEF][\x80-\xBF]{2}
| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences 11110xxx 10xxxxxx * 3
| [\xF1-\xF3][\x80-\xBF]{3}
| \xF4[\x80-\x8F][\x80-\xBF]{2}
)/x';
// Start at 1 instead of 0 since the first thing we do is decrement.
$count = 1;
do {
// We had some string left over from the last round, but we counted it in that last round.
$count--;
/*
* Split by UTF-8 character, limit to 1000 characters (last array element will contain
* the rest of the string).
*/
$pieces = preg_split( $regex, $str, 1000 );
// Increment.
$count += count( $pieces );
// If there's anything left over, repeat the loop.
} while ( $str = array_pop( $pieces ) );
// Fencepost: preg_split() always returns one extra item in the array.
return --$count;
}
if ( ! function_exists( 'hash_hmac' ) ) :
/**
* Compat function to mimic hash_hmac().
*
* The Hash extension is bundled with PHP by default since PHP 5.1.2.
* However, the extension may be explicitly disabled on select servers.
* As of PHP 7.4.0, the Hash extension is a core PHP extension and can no
* longer be disabled.
* I.e. when PHP 7.4.0 becomes the minimum requirement, this polyfill
* and the associated `_hash_hmac()` function can be safely removed.
*
* @ignore
* @since 3.2.0
*
* @see _hash_hmac()
*
* @param string $algo Hash algorithm. Accepts 'md5' or 'sha1'.
* @param string $data Data to be hashed.
* @param string $key Secret key to use for generating the hash.
* @param bool $raw_output Optional. Whether to output raw binary data (true),
* or lowercase hexits (false). Default false.
* @return string|false The hash in output determined by `$raw_output`. False if `$algo`
* is unknown or invalid.
*/
function hash_hmac( $algo, $data, $key, $raw_output = false ) {
return _hash_hmac( $algo, $data, $key, $raw_output );
}
endif;
/**
* Internal compat function to mimic hash_hmac().
*
* @ignore
* @since 3.2.0
*
* @param string $algo Hash algorithm. Accepts 'md5' or 'sha1'.
* @param string $data Data to be hashed.
* @param string $key Secret key to use for generating the hash.
* @param bool $raw_output Optional. Whether to output raw binary data (true),
* or lowercase hexits (false). Default false.
* @return string|false The hash in output determined by `$raw_output`. False if `$algo`
* is unknown or invalid.
*/
function _hash_hmac( $algo, $data, $key, $raw_output = false ) {
$packs = array(
'md5' => 'H32',
'sha1' => 'H40',
);
if ( ! isset( $packs[ $algo ] ) ) {
return false;
}
$pack = $packs[ $algo ];
if ( strlen( $key ) > 64 ) {
$key = pack( $pack, $algo( $key ) );
}
$key = str_pad( $key, 64, chr( 0 ) );
$ipad = ( substr( $key, 0, 64 ) ^ str_repeat( chr( 0x36 ), 64 ) );
$opad = ( substr( $key, 0, 64 ) ^ str_repeat( chr( 0x5C ), 64 ) );
$hmac = $algo( $opad . pack( $pack, $algo( $ipad . $data ) ) );
if ( $raw_output ) {
return pack( $pack, $hmac );
}
return $hmac;
}
if ( ! function_exists( 'json_encode' ) ) {
function json_encode( $string ) {
global $wp_json;
if ( ! ( $wp_json instanceof Services_JSON ) ) {
require_once( ABSPATH . WPINC . '/class-json.php' );
$wp_json = new Services_JSON();
}
return $wp_json->encodeUnsafe( $string );
}
}
if ( ! function_exists( 'json_decode' ) ) {
/**
* @global Services_JSON $wp_json
* @param string $string
* @param bool $assoc_array
* @return object|array
*/
function json_decode( $string, $assoc_array = false ) {
global $wp_json;
if ( ! ( $wp_json instanceof Services_JSON ) ) {
require_once( ABSPATH . WPINC . '/class-json.php' );
$wp_json = new Services_JSON();
}
$res = $wp_json->decode( $string );
if ( $assoc_array ) {
$res = _json_decode_object_helper( $res );
}
return $res;
}
/**
* @param object $data
* @return array
*/
function _json_decode_object_helper( $data ) {
if ( is_object( $data ) ) {
$data = get_object_vars( $data );
}
return is_array( $data ) ? array_map( __FUNCTION__, $data ) : $data;
}
}
if ( ! function_exists( 'hash_equals' ) ) :
/**
* Timing attack safe string comparison
*
* Compares two strings using the same time whether they're equal or not.
*
* Note: It can leak the length of a string when arguments of differing length are supplied.
*
* This function was added in PHP 5.6.
* However, the Hash extension may be explicitly disabled on select servers.
* As of PHP 7.4.0, the Hash extension is a core PHP extension and can no
* longer be disabled.
* I.e. when PHP 7.4.0 becomes the minimum requirement, this polyfill
* can be safely removed.
*
* @since 3.9.2
*
* @param string $a Expected string.
* @param string $b Actual, user supplied, string.
* @return bool Whether strings are equal.
*/
function hash_equals( $a, $b ) {
$a_length = strlen( $a );
if ( $a_length !== strlen( $b ) ) {
return false;
}
$result = 0;
// Do not attempt to "optimize" this.
for ( $i = 0; $i < $a_length; $i++ ) {
$result |= ord( $a[ $i ] ) ^ ord( $b[ $i ] );
}
return $result === 0;
}
endif;
// JSON_PRETTY_PRINT was introduced in PHP 5.4
// Defined here to prevent a notice when using it with wp_json_encode()
if ( ! defined( 'JSON_PRETTY_PRINT' ) ) {
define( 'JSON_PRETTY_PRINT', 128 );
}
if ( ! function_exists( 'json_last_error_msg' ) ) :
/**
* Retrieves the error string of the last json_encode() or json_decode() call.
*
* @since 4.4.0
*
* @internal This is a compatibility function for PHP <5.5
*
* @return bool|string Returns the error message on success, "No Error" if no error has occurred,
* or false on failure.
*/
function json_last_error_msg() {
// See https://core.trac.wordpress.org/ticket/27799.
if ( ! function_exists( 'json_last_error' ) ) {
return false;
}
$last_error_code = json_last_error();
// Just in case JSON_ERROR_NONE is not defined.
$error_code_none = defined( 'JSON_ERROR_NONE' ) ? JSON_ERROR_NONE : 0;
switch ( true ) {
case $last_error_code === $error_code_none:
return 'No error';
case defined( 'JSON_ERROR_DEPTH' ) && JSON_ERROR_DEPTH === $last_error_code:
return 'Maximum stack depth exceeded';
case defined( 'JSON_ERROR_STATE_MISMATCH' ) && JSON_ERROR_STATE_MISMATCH === $last_error_code:
return 'State mismatch (invalid or malformed JSON)';
case defined( 'JSON_ERROR_CTRL_CHAR' ) && JSON_ERROR_CTRL_CHAR === $last_error_code:
return 'Control character error, possibly incorrectly encoded';
case defined( 'JSON_ERROR_SYNTAX' ) && JSON_ERROR_SYNTAX === $last_error_code:
return 'Syntax error';
case defined( 'JSON_ERROR_UTF8' ) && JSON_ERROR_UTF8 === $last_error_code:
return 'Malformed UTF-8 characters, possibly incorrectly encoded';
case defined( 'JSON_ERROR_RECURSION' ) && JSON_ERROR_RECURSION === $last_error_code:
return 'Recursion detected';
case defined( 'JSON_ERROR_INF_OR_NAN' ) && JSON_ERROR_INF_OR_NAN === $last_error_code:
return 'Inf and NaN cannot be JSON encoded';
case defined( 'JSON_ERROR_UNSUPPORTED_TYPE' ) && JSON_ERROR_UNSUPPORTED_TYPE === $last_error_code:
return 'Type is not supported';
default:
return 'An unknown error occurred';
}
}
endif;
if ( ! interface_exists( 'JsonSerializable' ) ) {
define( 'WP_JSON_SERIALIZE_COMPATIBLE', true );
/**
* JsonSerializable interface.
*
* Compatibility shim for PHP <5.4
*
* @link https://secure.php.net/jsonserializable
*
* @since 4.4.0
*/
interface JsonSerializable {
// phpcs:ignore WordPress.NamingConventions.ValidFunctionName.MethodNameInvalid
public function jsonSerialize();
}
}
// random_int was introduced in PHP 7.0
if ( ! function_exists( 'random_int' ) ) {
require ABSPATH . WPINC . '/random_compat/random.php';
}
// sodium_crypto_box was introduced in PHP 7.2
if ( ! function_exists( 'sodium_crypto_box' ) ) {
require ABSPATH . WPINC . '/sodium_compat/autoload.php';
}
if ( ! function_exists( 'is_countable' ) ) {
/**
* Polyfill for is_countable() function added in PHP 7.3.
*
* Verify that the content of a variable is an array or an object
* implementing the Countable interface.
*
* @since 4.9.6
*
* @param mixed $var The value to check.
*
* @return bool True if `$var` is countable, false otherwise.
*/
function is_countable( $var ) {
return ( is_array( $var )
|| $var instanceof Countable
|| $var instanceof SimpleXMLElement
|| $var instanceof ResourceBundle
);
}
}
if ( ! function_exists( 'is_iterable' ) ) {
/**
* Polyfill for is_iterable() function added in PHP 7.1.
*
* Verify that the content of a variable is an array or an object
* implementing the Traversable interface.
*
* @since 4.9.6
*
* @param mixed $var The value to check.
*
* @return bool True if `$var` is iterable, false otherwise.
*/
function is_iterable( $var ) {
return ( is_array( $var ) || $var instanceof Traversable );
}
}