// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package fs

// FileFlags encodes file flags.
type FileFlags struct {
	// Direct indicates that I/O should be done directly.
	Direct bool

	// NonBlocking indicates that I/O should not block.
	NonBlocking bool

	// Sync indicates that any writes should be synchronous.
	Sync bool

	// Append indicates this file is append only.
	Append bool

	// Read indicates this file is readable.
	Read bool

	// Write indicates this file is writeable.
	Write bool

	// Pread indicates this file is readable at an arbitrary offset.
	Pread bool

	// Pwrite indicates this file is writable at an arbitrary offset.
	Pwrite bool

	// Directory indicates that this file must be a directory.
	Directory bool
}

// SettableFileFlags is a subset of FileFlags above that can be changed
// via fcntl(2) using the F_SETFL command.
type SettableFileFlags struct {
	// Direct indicates that I/O should be done directly.
	Direct bool

	// NonBlocking indicates that I/O should not block.
	NonBlocking bool

	// Append indicates this file is append only.
	Append bool
}

// Settable returns the subset of f that are settable.
func (f FileFlags) Settable() SettableFileFlags {
	return SettableFileFlags{
		Direct:      f.Direct,
		NonBlocking: f.NonBlocking,
		Append:      f.Append,
	}
}