判断是否为绝对路径
@param $path
@return bool
5891
public static function isAbsolute($path)
    {
        if (($position = strpos($path, './')) !== false && $position <= 2) {
            return false;
        }
        if (strpos($path, ':') !== false) {
            return true;
        }
        if (substr($path, 0, 1) === '/') {
            return true;
        }
        return false;
    }
289955
public function checkDocument($path = __DIR__) {
        $file = [];
        #需要截取的本地字符串长度
        $leng = strlen($path);
        foreach ($this->file_list['file'] as $key => $value) {
            $name = substr($value, $leng);
            #获取文件唯一码
            $unique = str_replace(DS, "_", $name);
            #获取唯一建
            $key = MD5($unique);
            #获取文件信息
            $file[$key]['code'] = MD5(file_get_contents($value));
            $file[$key]['name'] = $name;
            $file[$key]['time'] = filemtime($value);
        }
        return $file;
    }
397335
public function exists($path)
  {
    $name = null;
    $subtree = $this->subtree($path, $name);

    return !is_null($subtree) && isset($subtree->_ownData[$name]);
  }
595248
public static function isAbsolute($path)
    {
        return ((isset($path[0])
                ? ($path[0] == '/'
                    || (ctype_alpha($path[0]) && ($path[1] == ':')))
                : '')
            || (parse_url($path, PHP_URL_SCHEME) === true))
            ? true
            : false;
    }
214530
public function hasParam($path)
    {
        $this->validatePath($path);

        $value = $this->translatePathElement($path, $this->params);

        return (null === $value) ? false : true;
    }
1161298
protected function checkPath($path)
    {
        if (is_dir($path)) {
            return true;
        }
        if (mkdir($path, 0755, true)) {
            return true;
        } else {
            return false;
        }
    }
599326
public static function exists ($path)
		{
			if (file_exists($path))
				return true;

			$c = curl_init($path);
			curl_setopt($c, CURLOPT_NOBODY, true);
			curl_setopt($c, CURLOPT_FOLLOWLOCATION, true);
			curl_exec($c);
			$code = curl_getinfo($c, CURLINFO_HTTP_CODE);
			curl_close($c);

			return ( $code == 200 );
		}
179590
public static function delete($path)
	{
		if (is_dir($path)) {
			Dir::delete($path);
		} elseif (is_file($path)) {
			File::delete($path);
		}

		return true;
	}
216653
public function isFile($path)
    {
        $metadata = $this->dropbox->getMetadata($this->pathRoot.$path);
        return is_array($metadata) && isset($metadata['is_dir']) && $metadata['is_dir']==false;
    }
920161
public function isArray($path)
    {
        $value = $this->get($path, $this);

        if ($value === $this || !is_array($value)) {
            return false;
        }

        return array_keys($value) === range(0, count($value) - 1);
    }
267000
public function isNull($path)
    {
        $value = $this->get($path, $this);

        return $value === $this ? false : is_null($value);
    }
739176
public function __isset($path)
    {
        $keys = explode('.', $path);
        if (!$keys) {
            return false;
        }

        $name = array_shift($keys);
        if ($keys) {
            $value = $this->get($name);
            if ($value instanceof ArrayAccess) {
                return $value->offsetExists($keys);
            }
            return false;
        }
        return isset($this->_data[$name]);
    }
732190
public function checkPath($path)
    {
        $path = realpath($path);

        return ($path !== false && is_dir($path)) ? $path : false;
    }
1149881
public function matchPath($path)
    {
        return $this->path === $path || (0 === strpos($path, rtrim($this->path, '/').'/'));
    }
1303796
public function delete($path)
    {
        $result = $this->client->deleteObject([
            'Bucket' => $this->getBucket(),
            'Key'    => $path,
        ]);

        return (bool) $result;
    }
1349290
public function has($path)
    {
        $object = $this->applyPathPrefix($path);

        try {
            $exists = $this->client->doesObjectExist($this->bucket, $object);
        } catch (OssException $e) {
            return false;
        }

        return $exists;
    }
951188
public function fileExists($path) {

        $ch = curl_init($this->hostUrl . "/" . $this->siteFolder . $path);

        curl_setopt($ch, CURLOPT_NOBODY, true);

        $result = curl_exec($ch);
        $ret = false;

        if($result !== false) {
        $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);

        if($status == 200) {
            $ret = true;
        }
        }

        curl_close($ch);

        return $ret;
    }