PHP Iterator::valid方法代碼示例

 /**
  * Lazily append the next iterator to the chain
  */
 private function lazyAppend()
 {
     if (!parent::valid() and $this->iterators->valid()) {
         $this->append($this->iterators->current());
         $this->iterators->next();
     }
 }

 public function valid()
 {
     get_next:
     // Return true if this function has already been called for iteration.
     if ($this->currentRequest) {
         return true;
     }
     // Return false if we are at the end of the provided commands iterator.
     if (!$this->commands->valid()) {
         return false;
     }
     $command = $this->commands->current();
     if (!$command instanceof CommandInterface) {
         throw new \RuntimeException('All commands provided to the ' . __CLASS__ . ' must implement GuzzleHttp\\Command\\CommandInterface.' . ' Encountered a ' . Core::describeType($command) . ' value.');
     }
     $command->setFuture('lazy');
     $this->attachListeners($command, $this->eventListeners);
     // Prevent transfer exceptions from throwing.
     $command->getEmitter()->on('process', function (ProcessEvent $e) {
         if ($e->getException()) {
             $e->setResult(null);
         }
     }, RequestEvents::LATE);
     $builder = $this->requestBuilder;
     $result = $builder($command);
     // Skip commands that were intercepted with a result.
     if (isset($result['result'])) {
         $this->commands->next();
         goto get_next;
     }
     $this->currentRequest = $result['request'];
     return true;
 }

 private function valid()
 {
     if (!$this->data->valid()) {
         $this->rewind();
     }
     return TRUE;
 }

 /**
  * {@inheritdoc}
  */
 public function next()
 {
     $this->neighbour->next();
     if (!$this->neighbour->valid()) {
         $this->neighbour->rewind();
         parent::next();
     }
 }

	public function valid(){
		if ($this->isFirstValidCall === true){
			$this->innerHasItems = $this->innerIterator->valid();
			$this->isFirstValidCall = false;
			return true;
		}
		return $this->innerIterator->valid();
	}

 public function next()
 {
     $this->currentIt->next();
     if ($this->state === 1 && !$this->currentIt->valid()) {
         $this->currentIt = $this->it2;
         $this->state = 2;
     }
 }

 private function memo()
 {
     if (!$this->it->valid()) {
         return;
     }
     array_push($this->cache, array($this->it->key(), $this->it->current()));
     $this->cacheSize++;
 }

 private function fetch()
 {
     if ($this->it->valid()) {
         $this->v = $this->it->current();
         $this->k = $this->it->key();
         $fn = $this->fn;
         $fn($this->v, $this->k);
     }
 }

 private function fetch()
 {
     if ($this->it->valid()) {
         $v = $this->it->current();
         $k = $this->it->key();
         $this->v = $this->valueSelector->select($v, $k);
         $this->k = $this->keySelector->select($v, $k);
     }
 }

 public function valid()
 {
     if (!parent::valid()) {
         if ($this->source->valid()) {
             $this->append($this->transform($this->source->current()));
         }
     }
     return parent::valid();
 }

 /**
  * @return string
  */
 public function dir_readdir()
 {
     if ($this->iterator->valid()) {
         $result = $this->iterator->current();
         $this->iterator->next();
         return $result;
     } else {
         return false;
     }
 }

 /**
  * Initialize isSuspended.
  *
  * Called in walk() method.
  *
  * @return void
  */
 protected function initSuspended()
 {
     if ($this->lineHandler instanceof \IteratorIterator) {
         $this->isSuspended = $this->lineHandler->getInnerIterator()->valid();
     } elseif ($this->lineHandler instanceof \Iterator) {
         $this->isSuspended = $this->lineHandler->valid();
     } else {
         $this->isSuspended = false;
     }
 }

 /**
  * @param $limit
  * @return Resource[]
  */
 public function collect($limit = -1)
 {
     $resources = array();
     while ($limit && $this->iterator->valid()) {
         $resources[] = $this->iterator->current();
         $this->iterator->next();
         $limit--;
     }
     return $resources;
 }

 protected function fetch()
 {
     $this->buffer = array();
     for ($i = 0; $i < $this->chunkSize; $i++) {
         if (!$this->it->valid()) {
             return;
         }
         array_push($this->buffer, $this->it->current());
         $this->it->next();
     }
 }

 public function valid()
 {
     if ($this->usingCache) {
         return isset($this->array[$this->position]);
     }
     $valid = $this->innerIterator->valid();
     if (!$valid) {
         $this->usingCache = true;
     }
     return $valid;
 }