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<?php namespace SuperClosure\Analyzer;
use SuperClosure\Analyzer\Visitor\ThisDetectorVisitor;
use SuperClosure\Exception\ClosureAnalysisException;
use SuperClosure\Analyzer\Visitor\ClosureLocatorVisitor;
use SuperClosure\Analyzer\Visitor\MagicConstantVisitor;
use PhpParser\NodeTraverser;
use PhpParser\PrettyPrinter\Standard as NodePrinter;
use PhpParser\Error as ParserError;
use PhpParser\NodeVisitor\NameResolver;
use PhpParser\Parser as CodeParser;
use PhpParser\ParserFactory;
use PhpParser\Lexer\Emulative as EmulativeLexer;
/**
* This is the AST based analyzer.
*
* We're using reflection and AST-based code parser to analyze a closure and
* determine its code and context using the nikic/php-parser library. The AST
* based analyzer and has more capabilities than the token analyzer, but is,
* unfortunately, about 25 times slower.
*/
class AstAnalyzer extends ClosureAnalyzer
{
protected function determineCode(array &$data)
{
// Find the closure by traversing through a AST of the code.
// Note: This also resolves class names to their FQCNs while traversing.
$this->locateClosure($data);
// Make a second pass through the AST, but only through the closure's
// nodes, to resolve any magic constants to literal values.
$traverser = new NodeTraverser;
$traverser->addVisitor(new MagicConstantVisitor($data['location']));
$traverser->addVisitor($thisDetector = new ThisDetectorVisitor);
$data['ast'] = $traverser->traverse([$data['ast']])[0];
$data['hasThis'] = $thisDetector->detected;
// Bounce the updated AST down to a string representation of the code.
$data['code'] = (new NodePrinter)->prettyPrint([$data['ast']]);
}
/**
* Parses the closure's code and produces an abstract syntax tree (AST).
*
* @param array $data
*
* @throws ClosureAnalysisException if there is an issue finding the closure
*/
private function locateClosure(array &$data)
{
try {
$locator = new ClosureLocatorVisitor($data['reflection']);
$fileAst = $this->getFileAst($data['reflection']);
$fileTraverser = new NodeTraverser;
$fileTraverser->addVisitor(new NameResolver);
$fileTraverser->addVisitor($locator);
$fileTraverser->traverse($fileAst);
} catch (ParserError $e) {
// @codeCoverageIgnoreStart
throw new ClosureAnalysisException(
'There was an error analyzing the closure code.', 0, $e
);
// @codeCoverageIgnoreEnd
}
$data['ast'] = $locator->closureNode;
if (!$data['ast']) {
// @codeCoverageIgnoreStart
throw new ClosureAnalysisException(
'The closure was not found within the abstract syntax tree.'
);
// @codeCoverageIgnoreEnd
}
$data['location'] = $locator->location;
}
/**
* Returns the variables that in the "use" clause of the closure definition.
* These are referred to as the "used variables", "static variables", or
* "closed upon variables", "context" of the closure.
*
* @param array $data
*/
protected function determineContext(array &$data)
{
// Get the variable names defined in the AST
$refs = 0;
$vars = array_map(function ($node) use (&$refs) {
if ($node->byRef) {
$refs++;
}
return $node->var;
}, $data['ast']->uses);
$data['hasRefs'] = ($refs > 0);
// Get the variable names and values using reflection
$values = $data['reflection']->getStaticVariables();
// Combine the names and values to create the canonical context.
foreach ($vars as $name) {
if (isset($values[$name])) {
$data['context'][$name] = $values[$name];
}
}
}
/**
* @param \ReflectionFunction $reflection
*
* @throws ClosureAnalysisException
*
* @return \PhpParser\Node[]
*/
private function getFileAst(\ReflectionFunction $reflection)
{
$fileName = $reflection->getFileName();
if (!file_exists($fileName)) {
throw new ClosureAnalysisException(
"The file containing the closure, \"{$fileName}\" did not exist."
);
}
return $this->getParser()->parse(file_get_contents($fileName));
}
/**
* @return CodeParser
*/
private function getParser()
{
if (class_exists('PhpParser\ParserFactory')) {
return (new ParserFactory)->create(ParserFactory::PREFER_PHP7);
}
return new CodeParser(new EmulativeLexer);
}
}
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