<?php
/**
* JSONPath implementation for PHP.
*
* @license https://github.com/SoftCreatR/JSONPath/blob/main/LICENSE MIT License
*/
declare(strict_types=1);
namespace Flow\JSONPath;
use function explode;
use function in_array;
use function preg_match;
use function strlen;
use function substr;
use function trim;
class JSONPathLexer
{
/*
* Match within bracket groups
* Matches are whitespace insensitive
*/
public const MATCH_INDEX = '(?!\-)[\-\w]+ | \*'; // Eg. foo or 40f35757-2563-4790-b0b1-caa904be455f
public const MATCH_INDEXES = '\s* -?\d+ [-?\d,\s]+'; // Eg. 0,1,2
public const MATCH_SLICE = '[-\d:]+ | :'; // Eg. [0:2:1]
public const MATCH_QUERY_RESULT = '\s* \( .+? \) \s*'; // Eg. ?(@.length - 1)
public const MATCH_QUERY_MATCH = '\s* \?\(.+?\) \s*'; // Eg. ?(@.foo = "bar")
public const MATCH_INDEX_IN_SINGLE_QUOTES = '\s* \' (.+?)? \' \s*'; // Eg. 'bar'
public const MATCH_INDEX_IN_DOUBLE_QUOTES = '\s* " (.+?)? " \s*'; // Eg. "bar"
/**
* The expression being lexed.
*
* @var string
*/
protected $expression = '';
/**
* The length of the expression.
*
* @var int
*/
protected $expressionLength = 0;
public function __construct(string $expression)
{
$expression = trim($expression);
$len = strlen($expression);
if ($len > 1) {
if ($expression[0] === '$') {
$expression = substr($expression, 1);
$len--;
}
if ($expression[0] !== '.' && $expression[0] !== '[') {
$expression = '.' . $expression;
$len++;
}
$this->expression = $expression;
$this->expressionLength = $len;
}
}
/**
* @throws JSONPathException
*/
public function parseExpressionTokens(): array
{
$dotIndexDepth = 0;
$squareBracketDepth = 0;
$tokenValue = '';
$tokens = [];
for ($i = 0; $i < $this->expressionLength; $i++) {
$char = $this->expression[$i];
if (($squareBracketDepth === 0) && $char === '.') {
if ($this->lookAhead($i) === '.') {
$tokens[] = new JSONPathToken(JSONPathToken::T_RECURSIVE, null);
}
continue;
}
if ($char === '[') {
++$squareBracketDepth;
if ($squareBracketDepth === 1) {
continue;
}
}
if ($char === ']') {
--$squareBracketDepth;
if ($squareBracketDepth === 0) {
continue;
}
}
/*
* Within square brackets
*/
if ($squareBracketDepth > 0) {
$tokenValue .= $char;
if ($squareBracketDepth === 1 && $this->lookAhead($i) === ']') {
$tokens[] = $this->createToken($tokenValue);
$tokenValue = '';
}
}
/*
* Outside square brackets
*/
if ($squareBracketDepth === 0) {
$tokenValue .= $char;
// Double dot ".."
if ($char === '.' && $dotIndexDepth > 1) {
$tokens[] = $this->createToken($tokenValue);
$tokenValue = '';
continue;
}
if ($this->atEnd($i) || in_array($this->lookAhead($i), ['.', '['])) {
$tokens[] = $this->createToken($tokenValue);
$tokenValue = '';
--$dotIndexDepth;
}
}
}
if ($tokenValue !== '') {
$tokens[] = $this->createToken($tokenValue);
}
return $tokens;
}
protected function lookAhead(int $pos, int $forward = 1): ?string
{
return $this->expression[$pos + $forward] ?? null;
}
protected function atEnd(int $pos): bool
{
return $pos === $this->expressionLength;
}
/**
* @throws JSONPathException
*/
public function parseExpression(): array
{
return $this->parseExpressionTokens();
}
/**
* @throws JSONPathException
*/
protected function createToken(string $value): JSONPathToken
{
// The IDE doesn't like, what we do with $value, so let's
// move it to a separate variable, to get rid of any IDE warnings
$tokenValue = $value;
/** @var JSONPathToken|null $ret */
$ret = null;
if (preg_match('/^(' . static::MATCH_INDEX . ')$/xu', $tokenValue, $matches)) {
if (preg_match('/^-?\d+$/', $tokenValue)) {
$tokenValue = (int)$tokenValue;
}
$ret = new JSONPathToken(JSONPathToken::T_INDEX, $tokenValue);
} elseif (preg_match('/^' . static::MATCH_INDEXES . '$/xu', $tokenValue, $matches)) {
$tokenValue = explode(',', trim($tokenValue, ','));
foreach ($tokenValue as $i => $v) {
$tokenValue[$i] = (int)trim($v);
}
$ret = new JSONPathToken(JSONPathToken::T_INDEXES, $tokenValue);
} elseif (preg_match('/^' . static::MATCH_SLICE . '$/xu', $tokenValue, $matches)) {
$parts = explode(':', $tokenValue);
$tokenValue = [
'start' => isset($parts[0]) && $parts[0] !== '' ? (int)$parts[0] : null,
'end' => isset($parts[1]) && $parts[1] !== '' ? (int)$parts[1] : null,
'step' => isset($parts[2]) && $parts[2] !== '' ? (int)$parts[2] : null,
];
$ret = new JSONPathToken(JSONPathToken::T_SLICE, $tokenValue);
} elseif (preg_match('/^' . static::MATCH_QUERY_RESULT . '$/xu', $tokenValue)) {
$tokenValue = substr($tokenValue, 1, -1);
$ret = new JSONPathToken(JSONPathToken::T_QUERY_RESULT, $tokenValue);
} elseif (preg_match('/^' . static::MATCH_QUERY_MATCH . '$/xu', $tokenValue)) {
$tokenValue = substr($tokenValue, 2, -1);
$ret = new JSONPathToken(JSONPathToken::T_QUERY_MATCH, $tokenValue);
} elseif (
preg_match('/^' . static::MATCH_INDEX_IN_SINGLE_QUOTES . '$/xu', $tokenValue, $matches) ||
preg_match('/^' . static::MATCH_INDEX_IN_DOUBLE_QUOTES . '$/xu', $tokenValue, $matches)
) {
if (isset($matches[1])) {
$tokenValue = $matches[1];
$tokenValue = trim($tokenValue);
$possibleArray = false;
if ($matches[0][0] === '"') {
$possibleArray = explode('","', $tokenValue);
} elseif ($matches[0][0] === "'") {
$possibleArray = explode("','", $tokenValue);
}
if ($possibleArray !== false && count($possibleArray) > 1) {
$tokenValue = $possibleArray;
}
} else {
$tokenValue = '';
}
$ret = new JSONPathToken(JSONPathToken::T_INDEX, $tokenValue);
}
if ($ret !== null) {
return $ret;
}
throw new JSONPathException("Unable to parse token {$tokenValue} in expression: $this->expression");
}
}
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