1. Mirror, mirror on the wall:
Building a new PHP reflection library
James Titcumb
Dutch PHP Conference 2016

2. James Titcumb
www.jamestitcumb.com
www.roave.com
www.phphants.co.uk
www.phpsouthcoast.co.uk
@asgrim
Who is this guy?

3. Reflection
@asgrim

5. © 1937 Disney’s Snow White - disneyscreencaps.com

7. Mostly this...
public function testSomething()
{
$myObj = new Thing();
$propReflection = new ReflectionProperty($myObj, 'foo');
$propReflection->setAccessible(true);
$propReflection->setValue($myObj, 'whatever');
// ... whatever ...
}

8. ● Structure
● Metadata
● Values
● Type introspection
● Modification
Reflection

9. How does it work?

10. zend_object (zend_types.h)
● zend_class_entry *ce (zend.h)
○ zval* static_members_table
○ HashTable function_table
○ HashTable properties_info
○ HashTable constants_table
○ zend_class_entry** interfaces
○ zend_class_entry** traits
○ (…other stuff…)
Roughly...

11. ReflectionClass->hasMethod
GET_REFLECTION_OBJECT_PTR(ce);
lc_name = zend_str_tolower_dup(name, name_len);
if ((ce == zend_ce_closure && (name_len == sizeof(ZEND_INVOKE_FUNC_NAME)-1)
&& memcmp(lc_name, ZEND_INVOKE_FUNC_NAME, sizeof(ZEND_INVOKE_FUNC_NAME)-1) == 0)
|| zend_hash_str_exists(&ce->function_table, lc_name, name_len)) {
efree(lc_name);
RETURN_TRUE;
} else {
efree(lc_name);
RETURN_FALSE;
}

12. Okay. What now?

13. github.com/ /BetterReflection
Better Reflection!

15. What?

16. Why?

17. Features!

18. How?

21. Reflector
Source
Locator
PhpParser
Reflection

22. $reflection = new ReflectionClass(
MyExampleClass::class
);
$this->assertSame(
'ExampleClass',
$reflection->getShortName()
);

23. $reflection = ReflectionClass::createFromName(
MyExampleClass::class
);
$this->assertSame(
'ExampleClass',
$reflection->getShortName()
);

24. // In ReflectionClass :
public static function createFromName($className)
{
return ClassReflector::buildDefaultReflector()->reflect($className);
}

25. // In ClassReflector :
public static function buildDefaultReflector()
{
return new self(new AggregateSourceLocator([
new PhpInternalSourceLocator(),
new EvaledCodeSourceLocator(),
new AutoloadSourceLocator(),
]));
}

26. Reflector
Source
Locator
PhpParser
Reflection

27. Source Locators
● PhpInternalSourceLocator
● EvaledCodeSourceLocator
● AggregateSourceLocator
● ClosureSourceLocator
● ComposerSourceLocator
● SingleFileSourceLocator
● StringSourceLocator

28. StringSourceLocator
use BetterReflectionReflectorClassReflector;
use BetterReflectionSourceLocatorTypeStringSourceLocator;
$source = <<<EOF
<?php
class MyClassInString {}
EOF;
$reflector = new ClassReflector(new StringSourceLocator($source));
$classInfo = $reflector->reflect(MyClassInString::class);

29. However…

30. AutoloadSourceLocator
ReflectionClass::createFromName(new MyClass)
replace stream wrapper
disable error handling
call “class_exists”
restore stream wrapper
restore error handling
store attempted filename load
DO NOT LOAD FILE!
return stored filename
Read file and parse AST!

31. What’s next?
Now we have CODE!

32. Magic superpowers

33. source: http://goo.gl/HORwLQ

34. So what is AST?

35. Reflector
Source
Locator
PhpParser
Reflection

36. <?php
use PhpParserParserFactory;
$parser = (new ParserFactory)
->create(ParserFactory::PREFER_PHP7);
print_r($parser->parse(
file_get_contents('ast-demo-src.php')
));

37. <?php
echo "Hello world";

38. Echo statement
`-- String, value "Hello world"

39. <?php
echo "Hello " . "world";

40. Echo statement
`-- Concat
|-- Left
| `-- String, value "Hello "
`-- Right
`-- String, value "world"

41. <?php
$a = 5;
$b = 3;
echo $a + ($b * 2);

42. Assign statement
|-- Variable $a
`-- Integer, value 5
Assign statement
|-- Variable $b
`-- Integer, value 3
Echo statement
`-- Add operation
|-- Left
| `-- Variable $a
`-- Right
`-- Multiply operation
|-- Left
| `-- Variable $b
`-- Right
`-- Integer, value 2

43. So what?

44. Reflector
Source
Locator
PhpParser
Reflection

45. AST to Reflection

46. Benefits?

47. <?php
class Foo
{
private $bar;
public function thing()
{
}
}

48. Class, name Foo
|-- Statements
| |-- Property, name bar
| | |-- Type [private]
| | `-- Attributes [start line: 7, end line: 9]
| `-- Method, name thing
| |-- Type [public]
| |-- Parameters [...]
| |-- Statements [...]
| `-- Attributes [start line: 7, end line: 9]
`-- Attributes [start line: 3, end line: 10]

49. php-ast extension

50. Here be dragons!
Some voodoo...

51. class MyClass
{
public function foo()
{
return 5;
}
}

52. // Create the reflection first
// ***BEFORE*** class is loaded
$classInfo = ReflectionClass::createFromName('MyClass');
// Or use specific source locators as already shown

53. // Override the body...!
$methodInfo = $classInfo->getMethod('foo');
$methodInfo->setBodyFromClosure(function () {
return 4;
});

54. // Bring the code into context now
$printer = new CodePrinter();
$classCode = $printer->prettyPrint([
$classInfo->getAst(),
]);
eval($classCode);

55. // Now create an instance, and call the
// method on this...
$c = new MyClass();
var_dump($c->foo()); // will be 4!!!

57. astkit

58. $if = AstKit::parseString(<<<EOD
if (true) {
echo "This is a triumph.n";
} else {
echo "The cake is a lie.n";
}
EOD
);
$if->execute(); // First run, program is as-seen above
$const = $if->getChild(0)->getChild(0);
// Replace the "true" constant in the condition with false
$const->graft(0, false);
// Can also graft other AstKit nodes, instead of constants
$if->execute(); // Second run now takes the else path

59. Difficulties...

60. ReflectionClass implements Reflector {
/* Constants */
const integer IS_IMPLICIT_ABSTRACT = 16 ;
const integer IS_EXPLICIT_ABSTRACT = 32 ;
const integer IS_FINAL = 64 ;
/* Properties */
public $name ;
/* Methods */
public __construct ( mixed $argument )
public static string export ( mixed $argument [, bool $return = false ] )
public mixed getConstant ( string $name )
public array getConstants ( void )
public ReflectionMethod getConstructor ( void )
public array getDefaultProperties ( void )
public string getDocComment ( void )
public int getEndLine ( void )
public ReflectionExtension getExtension ( void )
public string getExtensionName ( void )
public string getFileName ( void )
public array getInterfaceNames ( void )
public array getInterfaces ( void )
public ReflectionMethod getMethod ( string $name )
public array getMethods ([ int $filter ] )
public int getModifiers ( void )
public string getName ( void )
public string getNamespaceName ( void )
public object getParentClass ( void )
public array getProperties ([ int $filter ] )
public ReflectionProperty getProperty ( string $name )
public string getShortName ( void )
public int getStartLine ( void )
public array getStaticProperties ( void )
Reflection API is a big!
public mixed getStaticPropertyValue ( string $name [, mixed &$def_value ] )
public array getTraitAliases ( void )
public array getTraitNames ( void )
public array getTraits ( void )
public bool hasConstant ( string $name )
public bool hasMethod ( string $name )
public bool hasProperty ( string $name )
public bool implementsInterface ( string $interface )
public bool inNamespace ( void )
public bool isAbstract ( void )
public bool isAnonymous ( void )
public bool isCloneable ( void )
public bool isFinal ( void )
public bool isInstance ( object $object )
public bool isInstantiable ( void )
public bool isInterface ( void )
public bool isInternal ( void )
public bool isIterateable ( void )
public bool isSubclassOf ( string $class )
public bool isTrait ( void )
public bool isUserDefined ( void )
public object newInstance ( mixed $args [, mixed $... ] )
public object newInstanceArgs ([ array $args ] )
public object newInstanceWithoutConstructor ( void )
public void setStaticPropertyValue ( string $name , string $value )
public string __toString ( void )
}

61. <?php
namespace ??????????;
use ?????????????????????????????????????;
class Foo
{
public function something()
{
throw new InvalidArgumentException('Oh noes!');
}
}
Type determination

62. <?php
namespace MyPackage;
use SomePackageInvalidArgumentException;
class Foo
{
public function something()
{
throw new InvalidArgumentException('Oh noes!');
}
}
Type determination

63. Type determination
● FindParameterType
● FindPropertyType
● FindReturnType
● FindTypeFromAst

64. $finder = new FindTypeFromAst();
$namespace = '';
if ($method->getDeclaringClass()->inNamespace()) {
$namespace = $method->getDeclaringClass()->getNamespaceName();
}
$type = $finder(
$className,
$method->getLocatedSource(),
$namespace
);
Type determination

65. DocBlock Parent
Traversal Type
Resolution

66. DocBlock Parent Traversal Type Resolution
class Foo {
/**
* @return int
*/
public function myMethod() { /* ... */ }
}
class Bar extends Foo {
/**
* {@inheritDoc}
*/
public function myMethod() { /* ... */ }
}
It’s an “int” return type!

67. DocBlock Parent Traversal Type Resolution
interface Blammo {
/**
* @return string
*/
public function myMethod();
}
class Foo {
/**
* @return int
*/
public function myMethod() { /* ... */ }
}