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|
use std::{fmt, ops};
use num_derive::FromPrimitive;
use num_traits::FromPrimitive as _;
pub mod log;
pub mod player;
/// Early filtering result.
///
/// This implements a [three-valued logic](https://en.wikipedia.org/wiki/Three-valued_logic),
/// similar to SQL's `NULL`.
#[derive(Debug, Copy, Clone, PartialEq, Eq, FromPrimitive)]
#[repr(i8)]
pub enum Inclusion {
/// The log should be included.
Include = 1,
/// The state is yet unknown.
Unknown = 0,
/// The log should be excluded.
Exclude = -1,
}
impl ops::Not for Inclusion {
type Output = Self;
fn not(self) -> Self::Output {
Inclusion::from_i8(-(self as i8)).unwrap()
}
}
impl ops::BitAnd<Inclusion> for Inclusion {
type Output = Self;
fn bitand(self, rhs: Inclusion) -> Self::Output {
Inclusion::from_i8((self as i8).min(rhs as i8)).unwrap()
}
}
impl ops::BitOr<Inclusion> for Inclusion {
type Output = Self;
fn bitor(self, rhs: Inclusion) -> Self::Output {
Inclusion::from_i8((self as i8).max(rhs as i8)).unwrap()
}
}
impl From<bool> for Inclusion {
fn from(data: bool) -> Self {
if data {
Inclusion::Include
} else {
Inclusion::Exclude
}
}
}
/// The main filter trait.
///
/// Filters are usually handled as a `Box<dyn Filter>`.
pub trait Filter<Early, Late>: Send + Sync + fmt::Debug {
/// Determine early (before processing all events) whether the log stands a chance to be
/// included.
///
/// Note that you can return [Inclusion::Unkown] if this filter cannot determine yet a definite
/// answer.
fn filter_early(&self, _: &Early) -> Inclusion {
Inclusion::Unknown
}
/// Return whether the log should be included, according to this filter.
fn filter(&self, _: &Late) -> bool;
}
#[derive(Debug, Clone, Copy)]
struct Const(pub bool);
impl<E, L> Filter<E, L> for Const {
fn filter_early(&self, _: &E) -> Inclusion {
self.0.into()
}
fn filter(&self, _: &L) -> bool {
self.0
}
}
/// Construct a `Filter` that always returns a fixed value.
pub fn constant<E, L>(output: bool) -> Box<dyn Filter<E, L>> {
Box::new(Const(output))
}
struct AndFilter<E, L>(Box<dyn Filter<E, L>>, Box<dyn Filter<E, L>>);
impl<E, L> Filter<E, L> for AndFilter<E, L> {
fn filter_early(&self, partial_evtc: &E) -> Inclusion {
let lhs = self.0.filter_early(partial_evtc);
// Short circuit behaviour
if lhs == Inclusion::Exclude {
Inclusion::Exclude
} else {
lhs & self.1.filter_early(partial_evtc)
}
}
fn filter(&self, log: &L) -> bool {
self.0.filter(log) && self.1.filter(log)
}
}
impl<E: 'static, L: 'static> ops::BitAnd<Box<dyn Filter<E, L>>> for Box<dyn Filter<E, L>> {
type Output = Box<dyn Filter<E, L>>;
fn bitand(self, rhs: Box<dyn Filter<E, L>>) -> Self::Output {
Box::new(AndFilter(self, rhs))
}
}
impl<E, L> fmt::Debug for AndFilter<E, L> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "({:?}) and ({:?})", self.0, self.1)
}
}
struct OrFilter<E, L>(Box<dyn Filter<E, L>>, Box<dyn Filter<E, L>>);
impl<E, L> Filter<E, L> for OrFilter<E, L> {
fn filter_early(&self, partial_evtc: &E) -> Inclusion {
let lhs = self.0.filter_early(partial_evtc);
// Short circuit behaviour
if lhs == Inclusion::Include {
Inclusion::Include
} else {
lhs | self.1.filter_early(partial_evtc)
}
}
fn filter(&self, log: &L) -> bool {
self.0.filter(log) || self.1.filter(log)
}
}
impl<E: 'static, L: 'static> ops::BitOr<Box<dyn Filter<E, L>>> for Box<dyn Filter<E, L>> {
type Output = Box<dyn Filter<E, L>>;
fn bitor(self, rhs: Box<dyn Filter<E, L>>) -> Self::Output {
Box::new(OrFilter(self, rhs))
}
}
impl<E, L> fmt::Debug for OrFilter<E, L> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "({:?}) or ({:?})", self.0, self.1)
}
}
struct NotFilter<E, L>(Box<dyn Filter<E, L>>);
impl<E, L> Filter<E, L> for NotFilter<E, L> {
fn filter_early(&self, partial_evtc: &E) -> Inclusion {
!self.0.filter_early(partial_evtc)
}
fn filter(&self, log: &L) -> bool {
!self.0.filter(log)
}
}
impl<E: 'static, L: 'static> ops::Not for Box<dyn Filter<E, L>> {
type Output = Box<dyn Filter<E, L>>;
fn not(self) -> Self::Output {
Box::new(NotFilter(self))
}
}
impl<E, L> fmt::Debug for NotFilter<E, L> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "not ({:?})", self.0)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_inclusion_not() {
use Inclusion::*;
assert_eq!(!Exclude, Include);
assert_eq!(!Include, Exclude);
assert_eq!(!Unknown, Unknown);
}
#[test]
fn test_inclusion_and() {
use Inclusion::*;
assert_eq!(Exclude & Exclude, Exclude);
assert_eq!(Exclude & Unknown, Exclude);
assert_eq!(Exclude & Include, Exclude);
assert_eq!(Unknown & Exclude, Exclude);
assert_eq!(Unknown & Unknown, Unknown);
assert_eq!(Unknown & Include, Unknown);
assert_eq!(Include & Exclude, Exclude);
assert_eq!(Include & Unknown, Unknown);
assert_eq!(Include & Include, Include);
}
#[test]
fn test_inclusion_or() {
use Inclusion::*;
assert_eq!(Exclude | Exclude, Exclude);
assert_eq!(Exclude | Unknown, Unknown);
assert_eq!(Exclude | Include, Include);
assert_eq!(Unknown | Exclude, Unknown);
assert_eq!(Unknown | Unknown, Unknown);
assert_eq!(Unknown | Include, Include);
assert_eq!(Include | Exclude, Include);
assert_eq!(Include | Unknown, Include);
assert_eq!(Include | Include, Include);
}
}
|
