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<?php |
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declare( strict_types = 1 ); |
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/** |
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* @licence GNU GPL v2+ |
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* @author Jeroen De Dauw < [email protected] > |
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*/ |
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class RewindableGenerator implements Iterator { |
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/** |
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* @var callable |
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*/ |
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private $generatorFunction; |
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/** |
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* @var Generator |
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*/ |
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private $generator; |
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/** |
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* @var callable|null |
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*/ |
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private $onRewind; |
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/** |
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* @param callable $generatorConstructionFunction A callable that should return a Generator |
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* @param callable $onRewind callable that gets invoked with 0 arguments after the iterator was rewinded |
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* |
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* @throws InvalidArgumentException |
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*/ |
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public function __construct( callable $generatorConstructionFunction, callable $onRewind = null ) { |
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$this->generatorFunction = $generatorConstructionFunction; |
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$this->onRewind = $onRewind; |
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$this->generateGenerator(); |
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} |
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private function generateGenerator() { |
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$this->generator = call_user_func( $this->generatorFunction ); |
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if ( !( $this->generator instanceof Generator ) ) { |
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throw new InvalidArgumentException( 'The callable needs to return a Generator' ); |
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} |
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} |
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/** |
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* Return the current element |
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* @see Iterator::current |
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* @link http://php.net/manual/en/iterator.current.php |
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* @return mixed |
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*/ |
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public function current() { |
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return $this->generator->current(); |
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} |
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/** |
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* Move forward to next element |
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* @see Iterator::next |
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* @link http://php.net/manual/en/iterator.next.php |
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*/ |
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public function next() { |
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$this->generator->next(); |
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} |
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/** |
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* Return the key of the current element |
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* @see Iterator::key |
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* @link http://php.net/manual/en/iterator.key.php |
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* @return mixed scalar on success, or null on failure. |
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*/ |
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public function key() { |
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return $this->generator->key(); |
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} |
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/** |
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* Checks if current position is valid |
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* @see Iterator::rewind |
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* @link http://php.net/manual/en/iterator.valid.php |
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* @return boolean |
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*/ |
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public function valid() { |
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return $this->generator->valid(); |
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} |
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/** |
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* Rewind the Iterator to the first element |
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* @see Iterator::rewind |
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* @link http://php.net/manual/en/iterator.rewind.php |
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*/ |
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public function rewind() { |
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$this->generateGenerator(); |
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if ( is_callable( $this->onRewind ) ) { |
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call_user_func( $this->onRewind ); |
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} |
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if ( defined( 'HHVM_VERSION' ) ) { |
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$this->generator->next(); |
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} |
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} |
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/** |
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* Sets a callable that gets invoked with 0 arguments after the iterator was rewinded. |
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* If a callable has been set already, an exception will be thrown. |
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* |
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* @since 1.1.0 |
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* |
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* @param callable $onRewind |
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* @throws InvalidArgumentException |
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*/ |
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public function onRewind( callable $onRewind ) { |
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if ( $this->onRewind !== null ) { |
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throw new InvalidArgumentException( 'Can only bind a onRewind handler once' ); |
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} |
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$this->onRewind = $onRewind; |
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1 |
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} |
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} |
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JeroenDeDauw /
RewindableGenerator
