Interface Flags

src/traits.rs:132–371

A set of defined flags using a bits type as storage. ## Implementing `Flags` This trait is implemented by the [`bitflags`](macro.bitflags.html) macro: ``` use bitflags::bitflags; bitflags! { struct MyFlags: u8 { const A = 1; const B = 1 << 1; } } ``` It can also be implemented manually: ``` use bitflags::{Flag, Flags}; struct MyFlags(u8); impl Flags for MyFlags {

```
*/
pub trait Flags: Sized + 'static {
    /// The set of defined flags.
    const FLAGS: &'static [Flag<Self>];

    /// The underlying bits type.
    type Bits: Bits;

    /// Get a flags value with all bits unset.
    fn empty() -> Self {
        Self::from_bits_retain(Self::Bits::EMPTY)
    }

    /// Get a flags value with all known bits set.
    fn all() -> Self {
        let mut truncated = Self::Bits::EMPTY;

        for flag in Self::FLAGS.iter() {
            truncated = truncated | flag.value().bits();
        }

        Self::from_bits_retain(truncated)
    }

    /// Get a flags value with all bits from named flags set.
    ///
    /// This method is equivalent to [`Flags::all`] unless [`Flags::FLAGS`] contains unnamed flags.
    fn all_named() -> Self {
        Self::from_bits_retain(
            Self::FLAGS
                .iter()
                .filter(|f| !f.name().is_empty())
                .fold(Self::empty().bits(), |acc, f| acc | f.value().bits()),
        )
    }

    /// Get the known bits from a flags value.
    fn known_bits(&self) -> Self::Bits {
        self.bits() & Self::all().bits()
    }

    /// Get the unknown bits from a flags value.
    fn unknown_bits(&self) -> Self::Bits {
        self.bits() & !Self::all().bits()
    }

    /// This method will return `true` if any unknown bits are set.
    fn contains_unknown_bits(&self) -> bool {
        self.unknown_bits() != Self::Bits::EMPTY
    }

    /// Get the underlying bits value.
    ///
    /// The returned value is exactly the bits set in this flags value.
    fn bits(&self) -> Self::Bits;

    /// Convert from a bits value.
    ///
    /// This method will return `None` if any unknown bits are set.