1<?php
2
3/**
4 * `ORDER BY` keyword parser.
5 */
6
7namespace PhpMyAdmin\SqlParser\Components;
8
9use PhpMyAdmin\SqlParser\Component;
10use PhpMyAdmin\SqlParser\Parser;
11use PhpMyAdmin\SqlParser\Token;
12use PhpMyAdmin\SqlParser\TokensList;
13
14/**
15 * `ORDER BY` keyword parser.
16 *
17 * @category   Keywords
18 *
19 * @license    https://www.gnu.org/licenses/gpl-2.0.txt GPL-2.0+
20 */
21class OrderKeyword extends Component
22{
23    /**
24     * The expression that is used for ordering.
25     *
26     * @var Expression
27     */
28    public $expr;
29
30    /**
31     * The order type.
32     *
33     * @var string
34     */
35    public $type;
36
37    /**
38     * Constructor.
39     *
40     * @param Expression $expr the expression that we are sorting by
41     * @param string     $type the sorting type
42     */
43    public function __construct($expr = null, $type = 'ASC')
44    {
45        $this->expr = $expr;
46        $this->type = $type;
47    }
48
49    /**
50     * @param Parser     $parser  the parser that serves as context
51     * @param TokensList $list    the list of tokens that are being parsed
52     * @param array      $options parameters for parsing
53     *
54     * @return OrderKeyword[]
55     */
56    public static function parse(Parser $parser, TokensList $list, array $options = array())
57    {
58        $ret = array();
59
60        $expr = new self();
61
62        /**
63         * The state of the parser.
64         *
65         * Below are the states of the parser.
66         *
67         *      0 --------------------[ expression ]-------------------> 1
68         *
69         *      1 ------------------------[ , ]------------------------> 0
70         *      1 -------------------[ ASC / DESC ]--------------------> 1
71         *
72         * @var int
73         */
74        $state = 0;
75
76        for (; $list->idx < $list->count; ++$list->idx) {
77            /**
78             * Token parsed at this moment.
79             *
80             * @var Token
81             */
82            $token = $list->tokens[$list->idx];
83
84            // End of statement.
85            if ($token->type === Token::TYPE_DELIMITER) {
86                break;
87            }
88
89            // Skipping whitespaces and comments.
90            if (($token->type === Token::TYPE_WHITESPACE) || ($token->type === Token::TYPE_COMMENT)) {
91                continue;
92            }
93
94            if ($state === 0) {
95                $expr->expr = Expression::parse($parser, $list);
96                $state = 1;
97            } elseif ($state === 1) {
98                if (($token->type === Token::TYPE_KEYWORD)
99                    && (($token->keyword === 'ASC') || ($token->keyword === 'DESC'))
100                ) {
101                    $expr->type = $token->keyword;
102                } elseif (($token->type === Token::TYPE_OPERATOR)
103                    && ($token->value === ',')
104                ) {
105                    if (! empty($expr->expr)) {
106                        $ret[] = $expr;
107                    }
108                    $expr = new self();
109                    $state = 0;
110                } else {
111                    break;
112                }
113            }
114        }
115
116        // Last iteration was not processed.
117        if (! empty($expr->expr)) {
118            $ret[] = $expr;
119        }
120
121        --$list->idx;
122
123        return $ret;
124    }
125
126    /**
127     * @param OrderKeyword|OrderKeyword[] $component the component to be built
128     * @param array                       $options   parameters for building
129     *
130     * @return string
131     */
132    public static function build($component, array $options = array())
133    {
134        if (is_array($component)) {
135            return implode(', ', $component);
136        }
137
138        return $component->expr . ' ' . $component->type;
139    }
140}
141