183 lines
5.1 KiB
PHP
183 lines
5.1 KiB
PHP
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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\Component\ExpressionLanguage;
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use Psr\Cache\CacheItemPoolInterface;
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use Symfony\Component\Cache\Adapter\ArrayAdapter;
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// Help opcache.preload discover always-needed symbols
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class_exists(ParsedExpression::class);
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/**
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* Allows to compile and evaluate expressions written in your own DSL.
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*
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* @author Fabien Potencier <fabien@symfony.com>
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*/
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class ExpressionLanguage
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{
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private $cache;
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private $lexer;
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private $parser;
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private $compiler;
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protected $functions = [];
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/**
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* @param ExpressionFunctionProviderInterface[] $providers
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*/
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public function __construct(CacheItemPoolInterface $cache = null, array $providers = [])
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{
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$this->cache = $cache ?? new ArrayAdapter();
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$this->registerFunctions();
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foreach ($providers as $provider) {
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$this->registerProvider($provider);
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}
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}
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/**
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* Compiles an expression source code.
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*
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* @param Expression|string $expression The expression to compile
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*
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* @return string
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*/
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public function compile($expression, array $names = [])
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{
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return $this->getCompiler()->compile($this->parse($expression, $names)->getNodes())->getSource();
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}
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/**
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* Evaluate an expression.
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*
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* @param Expression|string $expression The expression to compile
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*
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* @return mixed
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*/
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public function evaluate($expression, array $values = [])
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{
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return $this->parse($expression, array_keys($values))->getNodes()->evaluate($this->functions, $values);
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}
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/**
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* Parses an expression.
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*
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* @param Expression|string $expression The expression to parse
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*
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* @return ParsedExpression
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*/
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public function parse($expression, array $names)
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{
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if ($expression instanceof ParsedExpression) {
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return $expression;
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}
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asort($names);
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$cacheKeyItems = [];
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foreach ($names as $nameKey => $name) {
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$cacheKeyItems[] = \is_int($nameKey) ? $name : $nameKey.':'.$name;
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}
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$cacheItem = $this->cache->getItem(rawurlencode($expression.'//'.implode('|', $cacheKeyItems)));
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if (null === $parsedExpression = $cacheItem->get()) {
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$nodes = $this->getParser()->parse($this->getLexer()->tokenize((string) $expression), $names);
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$parsedExpression = new ParsedExpression((string) $expression, $nodes);
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$cacheItem->set($parsedExpression);
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$this->cache->save($cacheItem);
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}
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return $parsedExpression;
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}
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/**
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* Validates the syntax of an expression.
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*
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* @param Expression|string $expression The expression to validate
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* @param array|null $names The list of acceptable variable names in the expression, or null to accept any names
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*
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* @throws SyntaxError When the passed expression is invalid
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*/
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public function lint($expression, ?array $names): void
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{
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if ($expression instanceof ParsedExpression) {
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return;
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}
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$this->getParser()->lint($this->getLexer()->tokenize((string) $expression), $names);
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}
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/**
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* Registers a function.
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*
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* @param callable $compiler A callable able to compile the function
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* @param callable $evaluator A callable able to evaluate the function
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*
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* @throws \LogicException when registering a function after calling evaluate(), compile() or parse()
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*
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* @see ExpressionFunction
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*/
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public function register(string $name, callable $compiler, callable $evaluator)
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{
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if (null !== $this->parser) {
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throw new \LogicException('Registering functions after calling evaluate(), compile() or parse() is not supported.');
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}
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$this->functions[$name] = ['compiler' => $compiler, 'evaluator' => $evaluator];
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}
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public function addFunction(ExpressionFunction $function)
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{
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$this->register($function->getName(), $function->getCompiler(), $function->getEvaluator());
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}
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public function registerProvider(ExpressionFunctionProviderInterface $provider)
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{
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foreach ($provider->getFunctions() as $function) {
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$this->addFunction($function);
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}
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}
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protected function registerFunctions()
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{
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$this->addFunction(ExpressionFunction::fromPhp('constant'));
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}
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private function getLexer(): Lexer
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{
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if (null === $this->lexer) {
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$this->lexer = new Lexer();
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}
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return $this->lexer;
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}
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private function getParser(): Parser
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{
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if (null === $this->parser) {
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$this->parser = new Parser($this->functions);
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}
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return $this->parser;
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}
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private function getCompiler(): Compiler
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{
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if (null === $this->compiler) {
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$this->compiler = new Compiler($this->functions);
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}
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return $this->compiler->reset();
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}
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}
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