1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139

//! Traits and types for partially ordered sets.

/// A type that is partially ordered.
///
/// This trait is distinct from Rust's `PartialOrd` trait, because the implementation
/// of that trait precludes a distinct `Ord` implementation. We need an independent
/// trait if we want to have a partially ordered type that can also be sorted.
pub trait PartialOrder : Eq {
    /// Returns true iff one element is strictly less than the other.
    fn less_than(&self, other: &Self) -> bool {
        self.less_equal(other) && self != other
    }
    /// Returns true iff one element is less than or equal to the other.
    fn less_equal(&self, other: &Self) -> bool;
}

/// A type that is totally ordered.
///
/// This trait is a "carrier trait", in the sense that it adds no additional functionality
/// over `PartialOrder`, but instead indicates that the `less_than` and `less_equal` methods
/// are total, meaning that `x.less_than(&y)` is equivalent to `!y.less_equal(&x)`.
///
/// This trait is distinct from Rust's `Ord` trait, because several implementors of
/// `PartialOrd` also implement `Ord` for efficient canonicalization, deduplication,
/// and other sanity-maintaining operations.
pub trait TotalOrder : PartialOrder { }

macro_rules! implement_partial {
    ($($index_type:ty,)*) => (
        $(
            impl PartialOrder for $index_type {
                #[inline] fn less_than(&self, other: &Self) -> bool { self < other }
                #[inline] fn less_equal(&self, other: &Self) -> bool { self <= other }
            }
        )*
    )
}

macro_rules! implement_total {
    ($($index_type:ty,)*) => (
        $(
            impl TotalOrder for $index_type { }
        )*
    )
}

implement_partial!(u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize, (), ::std::time::Duration,);
implement_total!(u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize, (), ::std::time::Duration,);


use std::fmt::{Formatter, Error, Debug};

use crate::progress::Timestamp;
use crate::progress::timestamp::Refines;

impl<TOuter: Timestamp, TInner: Timestamp> Refines<TOuter> for Product<TOuter, TInner> {
    fn to_inner(other: TOuter) -> Self {
        Product::new(other, TInner::minimum())
    }
    fn to_outer(self: Product<TOuter, TInner>) -> TOuter {
        self.outer
    }
    fn summarize(path: <Self as Timestamp>::Summary) -> <TOuter as Timestamp>::Summary {
        path.outer
    }
}

/// A nested pair of timestamps, one outer and one inner.
///
/// We use `Product` rather than `(TOuter, TInner)` so that we can derive our own `PartialOrd`,
/// because Rust just uses the lexicographic total order.
#[derive(Abomonation, Copy, Clone, Hash, Eq, PartialEq, Default, Ord, PartialOrd, Serialize, Deserialize)]
pub struct Product<TOuter, TInner> {
    /// Outer timestamp.
    pub outer: TOuter,
    /// Inner timestamp.
    pub inner: TInner,
}

impl<TOuter, TInner> Product<TOuter, TInner> {
    /// Creates a new product from outer and inner coordinates.
    pub fn new(outer: TOuter, inner: TInner) -> Product<TOuter, TInner> {
        Product {
            outer,
            inner,
        }
    }
}

/// Debug implementation to avoid seeing fully qualified path names.
impl<TOuter: Debug, TInner: Debug> Debug for Product<TOuter, TInner> {
    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
        f.write_str(&format!("({:?}, {:?})", self.outer, self.inner))
    }
}

impl<TOuter: PartialOrder, TInner: PartialOrder> PartialOrder for Product<TOuter, TInner> {
    #[inline]
    fn less_equal(&self, other: &Self) -> bool {
        self.outer.less_equal(&other.outer) && self.inner.less_equal(&other.inner)
    }
}

impl<TOuter: Timestamp, TInner: Timestamp> Timestamp for Product<TOuter, TInner> {
    type Summary = Product<TOuter::Summary, TInner::Summary>;
    fn minimum() -> Self { Product { outer: TOuter::minimum(), inner: TInner::minimum() }}
}

use crate::progress::timestamp::PathSummary;
impl<TOuter: Timestamp, TInner: Timestamp> PathSummary<Product<TOuter, TInner>> for Product<TOuter::Summary, TInner::Summary> {
    #[inline]
    fn results_in(&self, product: &Product<TOuter, TInner>) -> Option<Product<TOuter, TInner>> {
        self.outer.results_in(&product.outer)
            .and_then(|outer|
                self.inner.results_in(&product.inner)
                    .map(|inner| Product::new(outer, inner))
            )
    }
    #[inline]
    fn followed_by(&self, other: &Product<TOuter::Summary, TInner::Summary>) -> Option<Product<TOuter::Summary, TInner::Summary>> {
        self.outer.followed_by(&other.outer)
            .and_then(|outer|
                self.inner.followed_by(&other.inner)
                    .map(|inner| Product::new(outer, inner))
            )
    }
}

/// A type that does not affect total orderedness.
///
/// This trait is not useful, but must be made public and documented or else Rust
/// complains about its existence in the constraints on the implementation of
/// public traits for public types.
pub trait Empty : PartialOrder { }

impl Empty for () { }
impl<T1: Empty, T2: Empty> Empty for Product<T1, T2> { }

impl<T1, T2> TotalOrder for Product<T1, T2> where T1: Empty, T2: TotalOrder { }