<?php
/**
* Defines a context class that is later extended to define other contexts.
*
* A context is a collection of keywords, operators and functions used for
* parsing.
*/
namespace PhpMyAdmin\SqlParser;
use PhpMyAdmin\SqlParser\Exceptions\LoaderException;
/**
* Holds the configuration of the context that is currently used.
*
* @category Contexts
*
* @license https://www.gnu.org/licenses/gpl-2.0.txt GPL-2.0+
*/
abstract class Context
{
/**
* The maximum length of a keyword.
*
* @see static::$TOKEN_KEYWORD
*
* @var int
*/
const KEYWORD_MAX_LENGTH = 30;
/**
* The maximum length of a label.
*
* @see static::$TOKEN_LABEL
* Ref: https://dev.mysql.com/doc/refman/5.7/en/statement-labels.html
*
* @var int
*/
const LABEL_MAX_LENGTH = 16;
/**
* The maximum length of an operator.
*
* @see static::$TOKEN_OPERATOR
*
* @var int
*/
const OPERATOR_MAX_LENGTH = 4;
/**
* The name of the default content.
*
* @var string
*/
public static $defaultContext = '\\PhpMyAdmin\\SqlParser\\Contexts\\ContextMySql50700';
/**
* The name of the loaded context.
*
* @var string
*/
public static $loadedContext = '\\PhpMyAdmin\\SqlParser\\Contexts\\ContextMySql50700';
/**
* The prefix concatenated to the context name when an incomplete class name
* is specified.
*
* @var string
*/
public static $contextPrefix = '\\PhpMyAdmin\\SqlParser\\Contexts\\Context';
/**
* List of keywords.
*
* Because, PHP's associative arrays are basically hash tables, it is more
* efficient to store keywords as keys instead of values.
*
* The value associated to each keyword represents its flags.
*
* @see Token::FLAG_KEYWORD_RESERVED Token::FLAG_KEYWORD_COMPOSED
* Token::FLAG_KEYWORD_DATA_TYPE Token::FLAG_KEYWORD_KEY
* Token::FLAG_KEYWORD_FUNCTION
*
* Elements are sorted by flags, length and keyword.
*
* @var array
*/
public static $KEYWORDS = array();
/**
* List of operators and their flags.
*
* @var array
*/
public static $OPERATORS = array(
// Some operators (*, =) may have ambiguous flags, because they depend on
// the context they are being used in.
// For example: 1. SELECT * FROM table; # SQL specific (wildcard)
// SELECT 2 * 3; # arithmetic
// 2. SELECT * FROM table WHERE foo = 'bar';
// SET @i = 0;
// @see Token::FLAG_OPERATOR_ARITHMETIC
'%' => 1,
'*' => 1,
'+' => 1,
'-' => 1,
'/' => 1,
// @see Token::FLAG_OPERATOR_LOGICAL
'!' => 2,
'!=' => 2,
'&&' => 2,
'<' => 2,
'<=' => 2,
'<=>' => 2,
'<>' => 2,
'=' => 2,
'>' => 2,
'>=' => 2,
'||' => 2,
// @see Token::FLAG_OPERATOR_BITWISE
'&' => 4,
'<<' => 4,
'>>' => 4,
'^' => 4,
'|' => 4,
'~' => 4,
// @see Token::FLAG_OPERATOR_ASSIGNMENT
':=' => 8,
// @see Token::FLAG_OPERATOR_SQL
'(' => 16,
')' => 16,
'.' => 16,
',' => 16,
';' => 16
);
/**
* The mode of the MySQL server that will be used in lexing, parsing and
* building the statements.
*
* @var int
*/
public static $MODE = 0;
/*
* Server SQL Modes
* https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html
*/
// Compatibility mode for Microsoft's SQL server.
// This is the equivalent of ANSI_QUOTES.
const SQL_MODE_COMPAT_MYSQL = 2;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_allow_invalid_dates
const SQL_MODE_ALLOW_INVALID_DATES = 1;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_ansi_quotes
const SQL_MODE_ANSI_QUOTES = 2;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_error_for_division_by_zero
const SQL_MODE_ERROR_FOR_DIVISION_BY_ZERO = 4;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_high_not_precedence
const SQL_MODE_HIGH_NOT_PRECEDENCE = 8;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_ignore_space
const SQL_MODE_IGNORE_SPACE = 16;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_auto_create_user
const SQL_MODE_NO_AUTO_CREATE_USER = 32;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_auto_value_on_zero
const SQL_MODE_NO_AUTO_VALUE_ON_ZERO = 64;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_backslash_escapes
const SQL_MODE_NO_BACKSLASH_ESCAPES = 128;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_dir_in_create
const SQL_MODE_NO_DIR_IN_CREATE = 256;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_dir_in_create
const SQL_MODE_NO_ENGINE_SUBSTITUTION = 512;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_field_options
const SQL_MODE_NO_FIELD_OPTIONS = 1024;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_key_options
const SQL_MODE_NO_KEY_OPTIONS = 2048;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_table_options
const SQL_MODE_NO_TABLE_OPTIONS = 4096;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_unsigned_subtraction
const SQL_MODE_NO_UNSIGNED_SUBTRACTION = 8192;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_zero_date
const SQL_MODE_NO_ZERO_DATE = 16384;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_zero_in_date
const SQL_MODE_NO_ZERO_IN_DATE = 32768;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_only_full_group_by
const SQL_MODE_ONLY_FULL_GROUP_BY = 65536;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_pipes_as_concat
const SQL_MODE_PIPES_AS_CONCAT = 131072;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_real_as_float
const SQL_MODE_REAL_AS_FLOAT = 262144;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_strict_all_tables
const SQL_MODE_STRICT_ALL_TABLES = 524288;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_strict_trans_tables
const SQL_MODE_STRICT_TRANS_TABLES = 1048576;
// Custom modes.
// The table and column names and any other field that must be escaped will
// not be.
// Reserved keywords are being escaped regardless this mode is used or not.
const SQL_MODE_NO_ENCLOSING_QUOTES = 1073741824;
/*
* Combination SQL Modes
* https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sql-mode-combo
*/
// REAL_AS_FLOAT, PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE
const SQL_MODE_ANSI = 393234;
// PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE, NO_KEY_OPTIONS,
// NO_TABLE_OPTIONS, NO_FIELD_OPTIONS,
const SQL_MODE_DB2 = 138258;
// PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE, NO_KEY_OPTIONS,
// NO_TABLE_OPTIONS, NO_FIELD_OPTIONS, NO_AUTO_CREATE_USER
const SQL_MODE_MAXDB = 138290;
// PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE, NO_KEY_OPTIONS,
// NO_TABLE_OPTIONS, NO_FIELD_OPTIONS
const SQL_MODE_MSSQL = 138258;
// PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE, NO_KEY_OPTIONS,
// NO_TABLE_OPTIONS, NO_FIELD_OPTIONS, NO_AUTO_CREATE_USER
const SQL_MODE_ORACLE = 138290;
// PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE, NO_KEY_OPTIONS,
// NO_TABLE_OPTIONS, NO_FIELD_OPTIONS
const SQL_MODE_POSTGRESQL = 138258;
// STRICT_TRANS_TABLES, STRICT_ALL_TABLES, NO_ZERO_IN_DATE, NO_ZERO_DATE,
// ERROR_FOR_DIVISION_BY_ZERO, NO_AUTO_CREATE_USER
const SQL_MODE_TRADITIONAL = 1622052;
// -------------------------------------------------------------------------
// Keyword.
/**
* Checks if the given string is a keyword.
*
* @param string $str string to be checked
* @param bool $isReserved checks if the keyword is reserved
*
* @return int|null
*/
public static function isKeyword($str, $isReserved = false)
{
$str = strtoupper($str);
if (isset(static::$KEYWORDS[$str])) {
if ($isReserved && ! (static::$KEYWORDS[$str] & Token::FLAG_KEYWORD_RESERVED)) {
return null;
}
return static::$KEYWORDS[$str];
}
return null;
}
// -------------------------------------------------------------------------
// Operator.
/**
* Checks if the given string is an operator.
*
* @param string $str string to be checked
*
* @return int|null the appropriate flag for the operator
*/
public static function isOperator($str)
{
if (! isset(static::$OPERATORS[$str])) {
return null;
}
return static::$OPERATORS[$str];
}
// -------------------------------------------------------------------------
// Whitespace.
/**
* Checks if the given character is a whitespace.
*
* @param string $str string to be checked
*
* @return bool
*/
public static function isWhitespace($str)
{
return ($str === ' ') || ($str === "\r") || ($str === "\n") || ($str === "\t");
}
// -------------------------------------------------------------------------
// Comment.
/**
* Checks if the given string is the beginning of a whitespace.
*
* @param string $str string to be checked
* @param mixed $end
*
* @return int|null the appropriate flag for the comment type
*/
public static function isComment($str, $end = false)
{
$len = strlen($str);
if ($len === 0) {
return null;
}
// If comment is Bash style (#):
if ($str[0] === '#') {
return Token::FLAG_COMMENT_BASH;
}
// If comment is opening C style (/*), warning, it could be a MySQL command (/*!)
if (($len > 1) && ($str[0] === '/') && ($str[1] === '*')) {
return ($len > 2) && ($str[2] === '!') ?
Token::FLAG_COMMENT_MYSQL_CMD : Token::FLAG_COMMENT_C;
}
// If comment is closing C style (*/), warning, it could conflicts with wildcard and a real opening C style.
// It would looks like the following valid SQL statement: "SELECT */* comment */ FROM...".
if (($len > 1) && ($str[0] === '*') && ($str[1] === '/')) {
return Token::FLAG_COMMENT_C;
}
// If comment is SQL style (--\s?):
if (($len > 2) && ($str[0] === '-')
&& ($str[1] === '-') && static::isWhitespace($str[2])
) {
return Token::FLAG_COMMENT_SQL;
}
if (($len === 2) && $end && ($str[0] === '-') && ($str[1] === '-')) {
return Token::FLAG_COMMENT_SQL;
}
return null;
}
// -------------------------------------------------------------------------
// Bool.
/**
* Checks if the given string is a boolean value.
* This actually check only for `TRUE` and `FALSE` because `1` or `0` are
* actually numbers and are parsed by specific methods.
*
* @param string $str string to be checked
*
* @return bool
*/
public static function isBool($str)
{
$str = strtoupper($str);
return ($str === 'TRUE') || ($str === 'FALSE');
}
// -------------------------------------------------------------------------
// Number.
/**
* Checks if the given character can be a part of a number.
*
* @param string $str string to be checked
*
* @return bool
*/
public static function isNumber($str)
{
return (($str >= '0') && ($str <= '9')) || ($str === '.')
|| ($str === '-') || ($str === '+') || ($str === 'e') || ($str === 'E');
}
// -------------------------------------------------------------------------
// Symbol.
/**
* Checks if the given character is the beginning of a symbol. A symbol
* can be either a variable or a field name.
*
* @param string $str string to be checked
*
* @return int|null the appropriate flag for the symbol type
*/
public static function isSymbol($str)
{
if (strlen($str) === 0) {
return null;
}
if ($str[0] === '@') {
return Token::FLAG_SYMBOL_VARIABLE;
} elseif ($str[0] === '`') {
return Token::FLAG_SYMBOL_BACKTICK;
} elseif ($str[0] === ':' || $str[0] === '?') {
return Token::FLAG_SYMBOL_PARAMETER;
}
return null;
}
// -------------------------------------------------------------------------
// String.
/**
* Checks if the given character is the beginning of a string.
*
* @param string $str string to be checked
*
* @return int|null the appropriate flag for the string type
*/
public static function isString($str)
{
if (strlen($str) === 0) {
return null;
}
if ($str[0] === '\'') {
return Token::FLAG_STRING_SINGLE_QUOTES;
} elseif ($str[0] === '"') {
return Token::FLAG_STRING_DOUBLE_QUOTES;
}
return null;
}
// -------------------------------------------------------------------------
// Delimiter.
/**
* Checks if the given character can be a separator for two lexeme.
*
* @param string $str string to be checked
*
* @return bool
*/
public static function isSeparator($str)
{
// NOTES: Only non alphanumeric ASCII characters may be separators.
// `~` is the last printable ASCII character.
return ($str <= '~') && ($str !== '_')
&& (($str < '0') || ($str > '9'))
&& (($str < 'a') || ($str > 'z'))
&& (($str < 'A') || ($str > 'Z'));
}
/**
* Loads the specified context.
*
* Contexts may be used by accessing the context directly.
*
* @param string $context name of the context or full class name that
* defines the context
*
* @throws LoaderException if the specified context doesn't exist
*/
public static function load($context = '')
{
if (empty($context)) {
$context = self::$defaultContext;
}
if ($context[0] !== '\\') {
// Short context name (must be formatted into class name).
$context = self::$contextPrefix . $context;
}
if (! class_exists($context)) {
throw @new LoaderException(
'Specified context ("' . $context . '") does not exist.',
$context
);
}
self::$loadedContext = $context;
self::$KEYWORDS = $context::$KEYWORDS;
}
/**
* Loads the context with the closest version to the one specified.
*
* The closest context is found by replacing last digits with zero until one
* is loaded successfully.
*
* @see Context::load()
*
* @param string $context name of the context or full class name that
* defines the context
*
* @return string|null The loaded context. `null` if no context was loaded.
*/
public static function loadClosest($context = '')
{
$length = strlen($context);
for ($i = $length; $i > 0;) {
try {
/* Trying to load the new context */
static::load($context);
return $context;
} catch (LoaderException $e) {
/* Replace last two non zero digits by zeroes */
do {
$i -= 2;
$part = substr($context, $i, 2);
/* No more numeric parts to strip */
if (! is_numeric($part)) {
break 2;
}
} while (intval($part) === 0 && $i > 0);
$context = substr($context, 0, $i) . '00' . substr($context, $i + 2);
}
}
/* Fallback to loading at least matching engine */
if (strncmp($context, 'MariaDb', 7) === 0) {
return static::loadClosest('MariaDb100300');
} elseif (strncmp($context, 'MySql', 5) === 0) {
return static::loadClosest('MySql50700');
}
return null;
}
/**
* Sets the SQL mode.
*
* @param string $mode The list of modes. If empty, the mode is reset.
*/
public static function setMode($mode = '')
{
static::$MODE = 0;
if (empty($mode)) {
return;
}
$mode = explode(',', $mode);
foreach ($mode as $m) {
static::$MODE |= constant('static::SQL_MODE_' . $m);
}
}
/**
* Escapes the symbol by adding surrounding backticks.
*
* @param array|string $str the string to be escaped
* @param string $quote quote to be used when escaping
*
* @return string|array
*/
public static function escape($str, $quote = '`')
{
if (is_array($str)) {
foreach ($str as $key => $value) {
$str[$key] = static::escape($value);
}
return $str;
}
if ((static::$MODE & self::SQL_MODE_NO_ENCLOSING_QUOTES)
&& (! static::isKeyword($str, true))
) {
return $str;
}
if (static::$MODE & self::SQL_MODE_ANSI_QUOTES) {
$quote = '"';
}
return $quote . str_replace($quote, $quote . $quote, $str) . $quote;
}
/**
* Returns char used to quote identifiers based on currently set SQL Mode (ie. standard or ANSI_QUOTES)
* @return string either " (double quote, ansi_quotes mode) or ` (backtick, standard mode)
*/
public static function getIdentifierQuote()
{
return self::hasMode(self::SQL_MODE_ANSI_QUOTES) ? '"' : '`';
}
/**
* Function verifies that given SQL Mode constant is currently set
*
* @return boolean false on empty param, true/false on given constant/int value
* @param int $flag for example Context::SQL_MODE_ANSI_QUOTES
*/
public static function hasMode($flag = null)
{
if (empty($flag)) {
return false;
}
return (self::$MODE & $flag) === $flag;
}
}
// Initializing the default context.
Context::load();