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/*
* The MIT License
*
* @author Brian Dayhoff <mopsyd@me.com>
* @copyright (c) 2017, Brian Dayhoff <mopsyd@me.com> all rights reserved.
* @license http://opensource.org/licenses/MIT The MIT License (MIT)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
namespace oroboros\core\traits\utilities\logic;
/**
* <Backreference Trait>
* Provides a simple means for a trait to get a reference to another trait method
* that called it, providing the fully qualified method name one level up the
* stack from the calling method, so it can determine it's caller.
* --------
* Traits provide extended method support to classes without requiring a direct,
* linear chain of inheritance. This allows functions to inherit subsets of
* related methods without declaring a parent class.
*
* In Oroboros core, ALL methods are granted to classes via traits,
* and the classes themselves are just containers that correlate their methods
* to an interface they are expected to honor. This approach maximizes
* interoperability, by entirely removing class inheritance as a requirement
* for extension of any class in this system.
*
* 3rd parties using this package are not expected to follow this approach,
* but ALL of our internal class and logic structure does.
* --------
*
* @author Brian Dayhoff <mopsyd@me.com>
* @license http://opensource.org/licenses/MIT The MIT License (MIT)
* @link bitbucket.org/oroborosframework/oroboros-core/wiki/development/api/contract_interface.md
* @category contract-interfaces
* @package oroboros/core
* @subpackage utilities
* @version 0.2.4
* @since 0.2.4-alpha
*/
trait BackreferenceTrait
{
/**
* -------------------------------------------------------------------------
* Extension Methods (protected)
*
* These methods may be extended by inheriting constructs as needed.
* They represent the interal api.
*
* @example
* class foo {
*
* use \oroboros\core\traits\utilities\BackReferenceTrait;
*
* public function whoCalledMe() {
* return $this->_getBackReference();
* }
*
* }
*
* //displays false
* $foo = new foo();
* var_dump($foo->whoCalledMe);
*
* @example
* //displays '\bar'
* function bar() {
* return new foo()->whoCalledMe();
* }
*
* var_dump(bar());
*
* @example
* //It also finds traits directly.
* trait baz
* {
* public function quux()
* {
* return new foo()->whoCalledMe();
* }
* }
* class foobar
* {
* use baz;
* }
*
* //displays '\baz::quux'
* var_dump( new foobar()->quux() );
*
* -------------------------------------------------------------------------
*/
/**
* Returns the accurate, immediate backreference of one prior level of the
* stack up from wherever it was called, honoring inheritance and trait
* definitions that were not overridden within a class.
* @return string|bool Returns false if backreference is a global call. Otherwise returns the fully qualified method or function declaration, from the class or trait that declared it.
*/
protected function _getBackReference()
{
$backtrace = debug_backtrace();
//This takes care of an invalid stack
if ( !array_key_exists( 2, $backtrace ) )
{
return false;
}
$reference = $backtrace[2];
//$reflector_caller = $this->_getBackReferenceTraceReferenceReflector( $backtrace[1] );
$reflector_reference = $this->_getBackReferenceTraceReferenceReflector( $backtrace[2] );
unset( $backtrace );
//This takes care of procedural functions, namespaced or otherwise.
if ( $reflector_reference instanceof \ReflectionFunction )
{
//not a class, return the literal
return '\\' . $reflector_reference->name;
}
return $this->_findBackReferenceRealInheritanceLocation( $reflector_reference,
$reference );
}
/**
* -------------------------------------------------------------------------
* Logic Methods (private)
*
* These methods are not externally exposed.
* They represent the actual work.
* -------------------------------------------------------------------------
*/
private function _getBackReferenceTraceReferenceReflector( array $reference )
{
//Figure out whether this is a global
//function and whether or not it is namespaced.
$has_class = isset( $reference['class'] );
$has_function = isset( $reference['function'] );
$has_namespace = isset( $reference['namespace'] );
//we cannot reflect a global command,
//which can happen if _getBackReference
//was called from a public method.
if ( !$has_class && !$has_function )
{
return false;
}
//construct the prefix.
$prefix = '\\' . (($has_namespace)
? $reference['namespace'] . '\\'
: null ) . (($has_class)
? $reference['class'] . '::'
: null);
if ( $has_class )
{
$reflector = new \ReflectionMethod( $prefix . $reference['function'] );
} else
{
$reflector = new \ReflectionFunction( $prefix . $reference['function'] );
}
return $reflector;
}
private function _findBackReferenceRealInheritanceLocation( \ReflectionFunctionAbstract $reflector,
array $reference )
{
$expected_class = '\\' . $reflector->class;
$traits = $this->_getBackReferenceMatchingTraits( $reflector );
$traits_match = array();
foreach ( $traits as
$trait )
{
if ( !method_exists( $trait, $reflector->name ) )
{
continue;
}
$traits_match[] = new \ReflectionMethod( '\\' . $trait . '::' . $reflector->name );
}
if ( empty( $traits_match ) )
{
//no traits have this method, it has to be from the provided class.
return '\\' . $reflector->class . '::' . $reflector->name;
}
//this will filter it down to one possibility,
//if there are multiple declarations of the
//same function within inherited traits.
if ( count( $traits_match ) > 1 )
{
//filter for trait inheritance
$top_level_traits = array();
foreach ( $traits_match as
$trait_valid )
{
$top_level_traits = array_merge( $top_level_traits,
$this->_filterBackReferenceTraitInheritance( $trait_valid,
$traits_match ) );
}
}
//We know it is not possible to have more than one result now,
//because otherwise it would cause a fatal error at compile time
//due to ambiguous inheritance of a method between the class are
//evaluating against and multiple traits (double diamond of death).
$check_trait = array_shift( $traits_match );
//Here we have two options.
//One is to analyze the file contents of the
//class and specifically check for the existence
//of function ${function_name}. This is more exact,
//but also a pretty heavy operation, and this needs
//to remain lightweight.
//
//So instead we are going to make an assumption that the class and
//the filename have the same text, and that the namespace (if provided)
//also reflects the class file path, as is typical with Psr-0 and Psr-4.
//This will reflect in the doc block to clarify also, because we cannot
//justify the overhead of scraping the whole filesystem every time this
//is used.
//It SHOULD be possible to scrape the file directly, to make this
//also compatible with nonstandard projects, but that will incur
//some performance impact in that case, and is better avoided if
//ossible during normal production. The file utility will need
//to be completed before this.
$class_scrape = false; //This is a placeholder for optionally allowing sanity checks against the literal files, which is too slow for normal runtime operation. Do not remove. See todo below.
if ( !$class_scrape )
{
//Compare class reflectors to get the file paths,
//and see if they correspond to the namespace and/or
//filename.
$reflector_class_literal = new \ReflectionClass( $reference['class'] );
//if true, it's the trait. If false, it's the class.
if ( strpos( $check_trait->getFileName(),
$this->_convertBackReferenceNameSpaceToRelativeFilePath( $check_trait->class ) ) !==
false )
{
return '\\' . $check_trait->class . '::' . $check_trait->name;
}
return '\\' . $check_trait->class . '::' . $check_trait->name;
} else
{
/**
* @todo We will abstract this out better with a opt-flag to scrape verbosely at request discretion at a later time.
*/
//This code will never be reached under the current build.
//Very near future releases will use this block,
//so it's a placeholder for expected functionality.
//Do not factor this out.
d( $reference['file'], $reference );
d( $top_level_traits, $traits_match, $reflector, $expected_class,
$traits, $reference['function'], count( $traits_match ) );
exit;
}
}
/**
* Will check if a reflector uses traits recursively
* through all levels of inheritance.
* @param \ReflectionFunctionAbstract $trait
*/
private function _getBackReferenceMatchingTraits( \ReflectionFunctionAbstract $instance )
{
$traits = class_uses( '\\' . $instance->class );
foreach ( $traits as
$trait )
{
if ( !method_exists( $trait, $instance->name ) )
{
//This trait does not inherit the specified method,
//and we can also rule out any that it uses on
//account of this.
continue;
}
$reflector = new \ReflectionMethod( '\\' . $trait . '::' . $instance->name );
$traits = array_merge( $traits,
$this->_getBackReferenceMatchingTraits( $reflector ) );
}
return $traits;
}
private function _filterBackReferenceTraitInheritance( \ReflectionFunctionAbstract $trait,
array &$traits )
{
//remove the current trait from the array
foreach ( $traits as
$key =>
$match )
{
if ( $match->class === $trait->class )
{
continue;
}
if ( in_array( $match->class, class_uses( $trait->class ) ) )
{
//our target inherits this trait,
//so it takes precedence.
//We can remove this one.
unset( $traits[$key] );
}
if ( empty( $traits ) )
{
//the instance is the only match.
return array(
$trait );
}
return $traits;
}
}
private function _convertBackReferenceNameSpaceToRelativeFilePath( $class )
{
$class_bits = explode( '\\', $class );
if ( count( $class_bits ) > 2 )
{
//trim the vendor level namespace
array_shift( $class_bits );
//This covers front controller classes that represent
//the package name by the same classname
if ( count( $class_bits ) > 1 )
{
//trim the package level namespace
array_shift( $class_bits );
}
}
$path = DIRECTORY_SEPARATOR . implode( DIRECTORY_SEPARATOR, $class_bits ) . '.php';
return $path;
}
}