itable( $file );
		}

		return $this->fs->is_writable( $file );
	}

	/**
	 * Checks if a file is readable.
	 *
	 * @since 4.1.9
	 *
	 * @param  string $file Path to file.
	 * @return bool         Whether $file is readable.
	 */
	public function isReadable( $file ) {
		if ( ! $this->isWpfsValid() ) {
			return @is_readable( $file );
		}

		return $this->fs->is_readable( $file );
	}

	/**
	 * Gets the file size (in bytes).
	 *
	 * @since 4.1.9
	 *
	 * @param  string   $file Path to file.
	 * @return int|bool       Size of the file in bytes on success, false on failure.
	 */
	public function size( $file ) {
		if ( ! $this->isWpfsValid() ) {
			return @filesize( $file );
		}

		return $this->fs->size( $file );
	}

	/**
	 * Checks if resource is a file.
	 *
	 * @since 4.1.9
	 *
	 * @param  string $file File path.
	 * @return bool         Whether $file is a file.
	 */
	public function isFile( $file ) {
		if ( ! $this->isWpfsValid() ) {
			return @is_file( $file );
		}

		return $this->fs->is_file( $file );
	}

	/**
	 * Checks if resource is a directory.
	 *
	 * @since 4.1.9
	 *
	 * @param  string $path Directory path.
	 * @return bool         Whether $path is a directory.
	 */
	public function isDir( $path ) {
		if ( ! $this->isWpfsValid() ) {
			return @is_dir( $path );
		}

		return $this->fs->is_dir( $path );
	}

	/**
	 * A simple check to ensure that the WP_Filesystem is valid.
	 *
	 * @since 4.1.9
	 *
	 * @return bool True if valid, false if not.
	 */
	public function isWpfsValid() {
		if (
			! is_a( $this->fs, 'WP_Filesystem_Base' ) ||
			(
				// Errors is a WP_Error object.
				! empty( $this->fs->errors ) &&
				// We directly check if the errors array is empty for compatibility with WP < 5.1.
				! empty( $this->fs->errors->errors )
			)
		) {
			return false;
		}

		return true;
	}

	/**
	 * In order to not have a conflict, we need to return a clone.
	 *
	 * @since 4.1.9
	 *
	 * @return Filesystem The cloned Filesystem object.
	 */
	public function noConflict() {
		return clone $this;
	}
}