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<?php
/**
* `JOIN` keyword parser.
*
* @package SqlParser
* @subpackage Components
*/
namespace SqlParser\Components;
use SqlParser\Component;
use SqlParser\Parser;
use SqlParser\Token;
use SqlParser\TokensList;
/**
* `JOIN` keyword parser.
*
* @category Keywords
* @package SqlParser
* @subpackage Components
* @author Dan Ungureanu <udan1107@gmail.com>
* @license http://opensource.org/licenses/GPL-2.0 GNU Public License
*/
class JoinKeyword extends Component
{
/**
* Types of join.
*
* @var array
*/
public static $JOINS = array(
'FULL JOIN' => 'FULL',
'INNER JOIN' => 'INNER',
'JOIN' => 'JOIN',
'LEFT JOIN' => 'LEFT',
'RIGHT JOIN' => 'RIGHT',
);
/**
* Type of this join.
*
* @see static::$JOINS
* @var string
*/
public $type;
/**
* Join expression.
*
* @var Expression
*/
public $expr;
/**
* Join conditions.
*
* @var Condition[]
*/
public $on;
/**
* @param Parser $parser The parser that serves as context.
* @param TokensList $list The list of tokens that are being parsed.
* @param array $options Parameters for parsing.
*
* @return JoinKeyword[]
*/
public static function parse(Parser $parser, TokensList $list, array $options = array())
{
$ret = array();
$expr = new JoinKeyword();
/**
* The state of the parser.
*
* Below are the states of the parser.
*
* 0 -----------------------[ JOIN ]----------------------> 1
*
* 1 -----------------------[ expr ]----------------------> 2
*
* 2 ------------------------[ ON ]-----------------------> 3
*
* 3 --------------------[ conditions ]-------------------> 0
*
* @var int $state
*/
$state = 0;
// By design, the parser will parse first token after the keyword.
// In this case, the keyword must be analyzed too, in order to determine
// the type of this join.
if ($list->idx > 0) {
--$list->idx;
}
for (; $list->idx < $list->count; ++$list->idx) {
/**
* Token parsed at this moment.
*
* @var Token $token
*/
$token = $list->tokens[$list->idx];
// End of statement.
if ($token->type === Token::TYPE_DELIMITER) {
break;
}
// Skipping whitespaces and comments.
if (($token->type === Token::TYPE_WHITESPACE) || ($token->type === Token::TYPE_COMMENT)) {
continue;
}
if ($state === 0) {
if (($token->type === Token::TYPE_KEYWORD)
&& (!empty(static::$JOINS[$token->value]))
) {
$expr->type = static::$JOINS[$token->value];
$state = 1;
} else {
break;
}
} elseif ($state === 1) {
$expr->expr = Expression::parse($parser, $list, array('skipColumn' => true));
$state = 2;
} elseif ($state === 2) {
if (($token->type === Token::TYPE_KEYWORD) && ($token->value === 'ON')) {
$state = 3;
}
} elseif ($state === 3) {
$expr->on = Condition::parse($parser, $list);
$ret[] = $expr;
$expr = new JoinKeyword();
$state = 0;
}
}
if (!empty($expr->type)) {
$ret[] = $expr;
}
--$list->idx;
return $ret;
}
/**
* @param JoinKeyword[] $component The component to be built.
* @param array $options Parameters for building.
*
* @return string
*/
public static function build($component, array $options = array())
{
$ret = array();
foreach ($component as $c) {
$ret[] = (($c->type === 'JOIN') ? 'JOIN ' : ($c->type . ' JOIN '))
. $c->expr . ' ON ' . Condition::build($c->on);
}
return implode(' ', $ret);
}
}
|
