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<?php
/**
* The result of the parser is an array of statements are extensions of the
* class defined here.
*
* A statement represents the result of parsing the lexemes.
*/
declare(strict_types=1);
namespace PhpMyAdmin\SqlParser;
use PhpMyAdmin\SqlParser\Components\FunctionCall;
use PhpMyAdmin\SqlParser\Components\OptionsArray;
use function array_flip;
use function array_keys;
use function count;
use function in_array;
use function stripos;
use function trim;
/**
* Abstract statement definition.
*/
abstract class Statement
{
/**
* Options for this statement.
*
* The option would be the key and the value can be an integer or an array.
*
* The integer represents only the index used.
*
* The array may have two keys: `0` is used to represent the index used and
* `1` is the type of the option (which may be 'var' or 'var='). Both
* options mean they expect a value after the option (e.g. `A = B` or `A B`,
* in which case `A` is the key and `B` is the value). The only difference
* is in the building process. `var` options are built as `A B` and `var=`
* options are built as `A = B`
*
* Two options that can be used together must have different values for
* indexes, else, when they will be used together, an error will occur.
*
* @var array
*/
public static $OPTIONS = [];
/**
* The clauses of this statement, in order.
*
* The value attributed to each clause is used by the builder and it may
* have one of the following values:
*
* - 1 = 01 - add the clause only
* - 2 = 10 - add the keyword
* - 3 = 11 - add both the keyword and the clause
*
* @var array
*/
public static $CLAUSES = [];
/** @var array */
public static $END_OPTIONS = [];
/**
* The options of this query.
*
* @see static::$OPTIONS
*
* @var OptionsArray
*/
public $options;
/**
* The index of the first token used in this statement.
*
* @var int
*/
public $first;
/**
* The index of the last token used in this statement.
*
* @var int
*/
public $last;
/**
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
*/
public function __construct(?Parser $parser = null, ?TokensList $list = null)
{
if (($parser === null) || ($list === null)) {
return;
}
$this->parse($parser, $list);
}
/**
* Builds the string representation of this statement.
*
* @return string
*/
public function build()
{
/**
* Query to be returned.
*
* @var string
*/
$query = '';
/**
* Clauses which were built already.
*
* It is required to keep track of built clauses because some fields,
* for example `join` is used by multiple clauses (`JOIN`, `LEFT JOIN`,
* `LEFT OUTER JOIN`, etc.). The same happens for `VALUE` and `VALUES`.
*
* A clause is considered built just after fields' value
* (`$this->field`) was used in building.
*
* @var array
*/
$built = [];
/**
* Statement's clauses.
*
* @var array
*/
$clauses = $this->getClauses();
foreach ($clauses as $clause) {
/**
* The name of the clause.
*
* @var string
*/
$name = $clause[0];
/**
* The type of the clause.
*
* @see self::$CLAUSES
*
* @var int
*/
$type = $clause[1];
/**
* The builder (parser) of this clause.
*
* @var Component
*/
$class = Parser::$KEYWORD_PARSERS[$name]['class'];
/**
* The name of the field that is used as source for the builder.
* Same field is used to store the result of parsing.
*
* @var string
*/
$field = Parser::$KEYWORD_PARSERS[$name]['field'];
// The field is empty, there is nothing to be built.
if (empty($this->$field)) {
continue;
}
// Checking if this field was already built.
if ($type & 1) {
if (! empty($built[$field])) {
continue;
}
$built[$field] = true;
}
// Checking if the name of the clause should be added.
if ($type & 2) {
$query = trim($query) . ' ' . $name;
}
// Checking if the result of the builder should be added.
if (! ($type & 1)) {
continue;
}
$query = trim($query) . ' ' . $class::build($this->$field);
}
return $query;
}
/**
* Parses the statements defined by the tokens list.
*
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
*
* @throws Exceptions\ParserException
*/
public function parse(Parser $parser, TokensList $list)
{
/**
* Array containing all list of clauses parsed.
* This is used to check for duplicates.
*
* @var array
*/
$parsedClauses = [];
// This may be corrected by the parser.
$this->first = $list->idx;
/**
* Whether options were parsed or not.
* For statements that do not have any options this is set to `true` by
* default.
*
* @var bool
*/
$parsedOptions = empty(static::$OPTIONS);
for (; $list->idx < $list->count; ++$list->idx) {
/**
* Token parsed at this moment.
*
* @var Token
*/
$token = $list->tokens[$list->idx];
// End of statement.
if ($token->type === Token::TYPE_DELIMITER) {
break;
}
// Checking if this closing bracket is the pair for a bracket
// outside the statement.
if (($token->value === ')') && ($parser->brackets > 0)) {
--$parser->brackets;
continue;
}
// Only keywords are relevant here. Other parts of the query are
// processed in the functions below.
if ($token->type !== Token::TYPE_KEYWORD) {
if (($token->type !== Token::TYPE_COMMENT) && ($token->type !== Token::TYPE_WHITESPACE)) {
$parser->error('Unexpected token.', $token);
}
continue;
}
// Unions are parsed by the parser because they represent more than
// one statement.
if (
($token->keyword === 'UNION') ||
($token->keyword === 'UNION ALL') ||
($token->keyword === 'UNION DISTINCT') ||
($token->keyword === 'EXCEPT') ||
($token->keyword === 'INTERSECT')
) {
break;
}
$lastIdx = $list->idx;
// ON DUPLICATE KEY UPDATE ...
// has to be parsed in parent statement (INSERT or REPLACE)
// so look for it and break
if ($this instanceof Statements\SelectStatement && $token->value === 'ON') {
++$list->idx; // Skip ON
// look for ON DUPLICATE KEY UPDATE
$first = $list->getNextOfType(Token::TYPE_KEYWORD);
$second = $list->getNextOfType(Token::TYPE_KEYWORD);
$third = $list->getNextOfType(Token::TYPE_KEYWORD);
if (
$first && $second && $third
&& $first->value === 'DUPLICATE'
&& $second->value === 'KEY'
&& $third->value === 'UPDATE'
) {
$list->idx = $lastIdx;
break;
}
}
$list->idx = $lastIdx;
/**
* The name of the class that is used for parsing.
*
* @var Component
*/
$class = null;
/**
* The name of the field where the result of the parsing is stored.
*
* @var string
*/
$field = null;
/**
* Parser's options.
*
* @var array
*/
$options = [];
// Looking for duplicated clauses.
if (
! empty(Parser::$KEYWORD_PARSERS[$token->value])
|| ! empty(Parser::$STATEMENT_PARSERS[$token->value])
) {
if (! empty($parsedClauses[$token->value])) {
$parser->error('This type of clause was previously parsed.', $token);
break;
}
$parsedClauses[$token->value] = true;
}
// Checking if this is the beginning of a clause.
// Fix Issue #221: As `truncate` is not a keyword
// but it might be the beginning of a statement of truncate,
// so let the value use the keyword field for truncate type.
$tokenValue = in_array($token->keyword, ['TRUNCATE']) ? $token->keyword : $token->value;
if (! empty(Parser::$KEYWORD_PARSERS[$tokenValue]) && $list->idx < $list->count) {
$class = Parser::$KEYWORD_PARSERS[$tokenValue]['class'];
$field = Parser::$KEYWORD_PARSERS[$tokenValue]['field'];
if (! empty(Parser::$KEYWORD_PARSERS[$tokenValue]['options'])) {
$options = Parser::$KEYWORD_PARSERS[$tokenValue]['options'];
}
}
// Checking if this is the beginning of the statement.
if (! empty(Parser::$STATEMENT_PARSERS[$token->keyword])) {
if (
! empty(static::$CLAUSES) // Undefined for some statements.
&& empty(static::$CLAUSES[$token->value])
) {
// Some keywords (e.g. `SET`) may be the beginning of a
// statement and a clause.
// If such keyword was found and it cannot be a clause of
// this statement it means it is a new statement, but no
// delimiter was found between them.
$parser->error(
'A new statement was found, but no delimiter between it and the previous one.',
$token
);
break;
}
if (! $parsedOptions) {
if (empty(static::$OPTIONS[$token->value])) {
// Skipping keyword because if it is not a option.
++$list->idx;
}
$this->options = OptionsArray::parse($parser, $list, static::$OPTIONS);
$parsedOptions = true;
}
} elseif ($class === null) {
if (
$this instanceof Statements\SelectStatement
&& ($token->value === 'FOR UPDATE'
|| $token->value === 'LOCK IN SHARE MODE')
) {
// Handle special end options in Select statement
// See Statements\SelectStatement::$END_OPTIONS
$this->end_options = OptionsArray::parse($parser, $list, static::$END_OPTIONS);
} elseif (
$this instanceof Statements\SetStatement
&& ($token->value === 'COLLATE'
|| $token->value === 'DEFAULT')
) {
// Handle special end options in SET statement
// See Statements\SetStatement::$END_OPTIONS
$this->end_options = OptionsArray::parse($parser, $list, static::$END_OPTIONS);
} else {
// There is no parser for this keyword and isn't the beginning
// of a statement (so no options) either.
$parser->error('Unrecognized keyword.', $token);
continue;
}
}
$this->before($parser, $list, $token);
// Parsing this keyword.
if ($class !== null) {
// We can't parse keyword at the end of statement
if ($list->idx >= $list->count) {
$parser->error('Keyword at end of statement.', $token);
continue;
}
++$list->idx; // Skipping keyword or last option.
$this->$field = $class::parse($parser, $list, $options);
}
$this->after($parser, $list, $token);
// #223 Here may make a patch, if last is delimiter, back one
if ($class !== FunctionCall::class || $list->offsetGet($list->idx)->type !== Token::TYPE_DELIMITER) {
continue;
}
--$list->idx;
}
// This may be corrected by the parser.
$this->last = --$list->idx; // Go back to last used token.
}
/**
* Function called before the token is processed.
*
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
* @param Token $token the token that is being parsed
*/
public function before(Parser $parser, TokensList $list, Token $token)
{
}
/**
* Function called after the token was processed.
*
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
* @param Token $token the token that is being parsed
*/
public function after(Parser $parser, TokensList $list, Token $token)
{
}
/**
* Gets the clauses of this statement.
*
* @return array
*/
public function getClauses()
{
return static::$CLAUSES;
}
/**
* Builds the string representation of this statement.
*
* @see static::build
*
* @return string
*/
public function __toString()
{
return $this->build();
}
/**
* Validates the order of the clauses in parsed statement
* Ideally this should be called after successfully
* completing the parsing of each statement.
*
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
*
* @return bool
*
* @throws Exceptions\ParserException
*/
public function validateClauseOrder($parser, $list)
{
$clauses = array_flip(array_keys($this->getClauses()));
if (empty($clauses) || count($clauses) === 0) {
return true;
}
$minIdx = -1;
/**
* For tracking JOIN clauses in a query
* = 0 - JOIN not found till now
* > 0 - Index of first JOIN clause in the statement.
*
* @var int
*/
$minJoin = 0;
/**
* For tracking JOIN clauses in a query
* = 0 - JOIN not found till now
* > 0 - Index of last JOIN clause
* (which appears together with other JOINs)
* in the statement.
*
* @var int
*/
$maxJoin = 0;
$error = 0;
$lastIdx = 0;
foreach ($clauses as $clauseType => $index) {
$clauseStartIdx = Utils\Query::getClauseStartOffset($this, $list, $clauseType);
if (
$clauseStartIdx !== -1
&& $this instanceof Statements\SelectStatement
&& ($clauseType === 'FORCE'
|| $clauseType === 'IGNORE'
|| $clauseType === 'USE')
) {
// TODO: ordering of clauses in a SELECT statement with
// Index hints is not supported
return true;
}
// Handle ordering of Multiple Joins in a query
if ($clauseStartIdx !== -1) {
if ($minJoin === 0 && stripos($clauseType, 'JOIN')) {
// First JOIN clause is detected
$minJoin = $maxJoin = $clauseStartIdx;
} elseif ($minJoin !== 0 && ! stripos($clauseType, 'JOIN')) {
// After a previous JOIN clause, a non-JOIN clause has been detected
$maxJoin = $lastIdx;
} elseif ($maxJoin < $clauseStartIdx && stripos($clauseType, 'JOIN')) {
$error = 1;
}
}
if ($clauseStartIdx !== -1 && $clauseStartIdx < $minIdx) {
if ($minJoin === 0 || $error === 1) {
$token = $list->tokens[$clauseStartIdx];
$parser->error('Unexpected ordering of clauses.', $token);
return false;
}
$minIdx = $clauseStartIdx;
} elseif ($clauseStartIdx !== -1) {
$minIdx = $clauseStartIdx;
}
$lastIdx = $clauseStartIdx !== -1 ? $clauseStartIdx : $lastIdx;
}
return true;
}
}