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<?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.
*
* @package SqlParser
*/
namespace SqlParser;
/**
* Holds the configuration of the context that is currently used.
*
* @category Contexts
* @package SqlParser
* @author Dan Ungureanu <udan1107@gmail.com>
* @license http://opensource.org/licenses/GPL-2.0 GNU Public License
*/
abstract class Context
{
/**
* The maximum length of a keyword.
*
* @see static::$TOKEN_KEYWORD
*
* @var int
*/
const KEYWORD_MAX_LENGTH = 30;
/**
* The maximum length of an operator.
*
* @see static::$TOKEN_OPERATOR
*
* @var int
*/
const OPERATOR_MAX_LENGTH = 4;
/**
* The name of the default content.
*
* @var string
*/
public static $defaultContext = '\\SqlParser\\Contexts\\ContextMySql50700';
/**
* The name of the loaded context.
*
* @var string
*/
public static $loadedContext = '\\SqlParser\\Contexts\\ContextMySql50700';
/**
* The prefix concatenated to the context name when an incomplete class name
* is specified.
*
* @var string
*/
public static $contextPrefix = '\\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_*
*
* 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,
);
/**
* 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 COMPAT_MYSQL = 2;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_allow_invalid_dates
const ALLOW_INVALID_DATES = 1;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_ansi_quotes
const ANSI_QUOTES = 2;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_error_for_division_by_zero
const ERROR_FOR_DIVISION_BY_ZERO = 4;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_high_not_precedence
const HIGH_NOT_PRECEDENCE = 8;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_ignore_space
const IGNORE_SPACE = 16;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_auto_create_user
const NO_AUTO_CREATE_USER = 32;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_auto_value_on_zero
const NO_AUTO_VALUE_ON_ZERO = 64;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_backslash_escapes
const NO_BACKSLASH_ESCAPES = 128;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_dir_in_create
const NO_DIR_IN_CREATE = 256;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_dir_in_create
const NO_ENGINE_SUBSTITUTION = 512;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_field_options
const NO_FIELD_OPTIONS = 1024;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_key_options
const NO_KEY_OPTIONS = 2048;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_table_options
const NO_TABLE_OPTIONS = 4096;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_unsigned_subtraction
const NO_UNSIGNED_SUBTRACTION = 8192;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_zero_date
const NO_ZERO_DATE = 16384;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_no_zero_in_date
const NO_ZERO_IN_DATE = 32768;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_only_full_group_by
const ONLY_FULL_GROUP_BY = 65536;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_pipes_as_concat
const PIPES_AS_CONCAT = 131072;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_real_as_float
const REAL_AS_FLOAT = 262144;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_strict_all_tables
const STRICT_ALL_TABLES = 524288;
// https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html#sqlmode_strict_trans_tables
const STRICT_TRANS_TABLES = 1048576;
/*
* 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 $isReserved Checks if the keyword is reserved.
*
* @return int
*/
public static function isKeyword($str, $isReserved = false)
{
$str = strtoupper($str);
if (isset(static::$KEYWORDS[$str])) {
if ($isReserved) {
if (!(static::$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 $str String to be checked.
*
* @return int The appropriate flag for the operator.
*/
public static function isOperator($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 $str String to be checked.
*
* @return int The appropriate flag for the comment type.
*/
public static function isComment($str)
{
$len = strlen($str);
if ($str[0] === '#') {
return Token::FLAG_COMMENT_BASH;
} elseif (($len > 1) && ($str[0] === '/') && ($str[1] === '*')) {
return (($len > 2) && ($str[2] == '!')) ?
Token::FLAG_COMMENT_MYSQL_CMD : Token::FLAG_COMMENT_C;
} elseif (($len > 1) && ($str[0] === '*') && ($str[1] === '/')) {
return Token::FLAG_COMMENT_C;
} elseif (($len > 2) && ($str[0] === '-')
&& ($str[1] === '-') && (static::isWhitespace($str[2]))
) {
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 $str String to be checked.
*
* @return int The appropriate flag for the symbol type.
*/
public static function isSymbol($str)
{
if ($str[0] === '@') {
return Token::FLAG_SYMBOL_VARIABLE;
} elseif ($str[0] === '`') {
return Token::FLAG_SYMBOL_BACKTICK;
}
return null;
}
// -------------------------------------------------------------------------
// String.
/**
* Checks if the given character is the beginning of a string.
*
* @param string $str String to be checked.
*
* @return int The appropriate flag for the string type.
*/
public static function isString($str)
{
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 ASCII characters may be separators.
// `~` is the last printable ASCII character.
return ($str <= '~') && (!ctype_alnum($str)) && ($str !== '_');
}
/**
* Loads the specified context.
*
* Contexts may be used by accessing the context directly.
*
* @param string $context Name of the context or full class name that
* defines the context.
*
* @throws \Exception If the specified context doesn't exist.
*
* @return void
*/
public static function load($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 Exception(
'Specified context ("' . $context . '") does not exist.'
);
}
self::$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 $context Name of the context or full class name that
* defines the context.
*
* @return string The loaded context. `null` if no context was loaded.
*/
public static function loadClosest($context = '')
{
/**
* The number of replaces done by `preg_replace`.
* This actually represents whether a new context was generated or not.
*
* @var int $count
*/
$count = 0;
// As long as a new context can be generated, we try to load it.
do {
try {
// Trying to load the new context.
static::load($context);
} catch (Exception $e) {
// If it didn't work, we are looking for a new one and skipping
// over to the next generation that will try the new context.
$context = preg_replace(
'/[1-9](0*)$/', '0$1', $context, -1, $count
);
continue;
}
// Last generated context was valid (did not throw any exceptions).
// So we return it, to let the user know what context was loaded.
return $context;
} while ($count !== 0);
return null;
}
/**
* Sets the SQL mode.
*
* @param string $mode The list of modes. If empty, the mode is reset.
*
* @return void
*/
public static function setMode($mode = '')
{
static::$MODE = 0;
if (empty($mode)) {
return;
}
$mode = explode(',', $mode);
foreach ($mode as $m) {
static::$MODE |= constant('static::' . $m);
}
}
/**
* Escapes the symbol by adding surrounding backticks.
*
* @param array|string $str The string to be escaped.
* @param string $quote Quote to be used when escaping.
*
* @return string
*/
public static function escape($str, $quote = '`')
{
if (is_array($str)) {
foreach ($str as $key => $value) {
$str[$key] = static::escape($value);
}
return $str;
}
if (static::$MODE & Context::ANSI_QUOTES) {
$quote = '"';
}
return $quote . str_replace($quote, $quote . $quote, $str) . $quote;
}
}
// Initialing the default context.
Context::load();
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