finality_grandpa/
weights.rs

1// Copyright 2019 Parity Technologies (UK) Ltd
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! This module lays out the rules for the arithmetic of vote(r) weights.
16
17use crate::std::{
18	cmp::Ordering,
19	fmt,
20	num::NonZeroU64,
21	ops::{Add, Sub},
22};
23
24/// The accumulated weight of any number of voters (possibly none).
25#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
26pub struct VoteWeight(pub u64);
27
28impl fmt::Display for VoteWeight {
29	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
30		write!(f, "{}", self.0)
31	}
32}
33
34impl Add for VoteWeight {
35	type Output = Self;
36
37	fn add(self, rhs: Self) -> Self {
38		VoteWeight(self.0.saturating_add(rhs.0))
39	}
40}
41
42impl Add<VoterWeight> for VoteWeight {
43	type Output = Self;
44
45	fn add(self, rhs: VoterWeight) -> Self {
46		VoteWeight(self.0.saturating_add(rhs.0.get()))
47	}
48}
49
50impl Sub for VoteWeight {
51	type Output = Self;
52
53	fn sub(self, rhs: Self) -> Self {
54		VoteWeight(self.0.saturating_sub(rhs.0))
55	}
56}
57
58impl Sub<VoterWeight> for VoteWeight {
59	type Output = Self;
60
61	fn sub(self, rhs: VoterWeight) -> Self {
62		self - VoteWeight(rhs.get())
63	}
64}
65
66impl PartialEq<VoterWeight> for VoteWeight {
67	fn eq(&self, other: &VoterWeight) -> bool {
68		self.0 == other.get()
69	}
70}
71
72impl PartialOrd<VoterWeight> for VoteWeight {
73	fn partial_cmp(&self, other: &VoterWeight) -> Option<Ordering> {
74		Some(self.0.cmp(&other.0.get()))
75	}
76}
77
78impl From<u64> for VoteWeight {
79	fn from(weight: u64) -> Self {
80		VoteWeight(weight)
81	}
82}
83
84/// The (non-zero) weight of one or more voters.
85///
86/// Having a non-zero weight is part of the definition of being a voter.
87#[derive(PartialEq, Eq, Copy, Clone, Debug)]
88pub struct VoterWeight(pub NonZeroU64);
89
90impl fmt::Display for VoterWeight {
91	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
92		write!(f, "{}", self.0)
93	}
94}
95
96impl VoterWeight {
97	pub fn new(weight: u64) -> Option<Self> {
98		NonZeroU64::new(weight).map(Self)
99	}
100
101	pub fn get(self) -> u64 {
102		self.0.get()
103	}
104}
105
106impl Sub<VoteWeight> for VoterWeight {
107	type Output = VoteWeight;
108
109	fn sub(self, rhs: VoteWeight) -> VoteWeight {
110		VoteWeight(self.0.get()) - rhs
111	}
112}
113
114impl Sub<VoterWeight> for VoterWeight {
115	type Output = VoteWeight;
116
117	fn sub(self, rhs: VoterWeight) -> VoteWeight {
118		VoteWeight(self.0.get()) - VoteWeight(rhs.get())
119	}
120}
121
122#[cfg(feature = "std")]
123impl std::convert::TryFrom<u64> for VoterWeight {
124	type Error = &'static str;
125
126	fn try_from(weight: u64) -> Result<Self, Self::Error> {
127		VoterWeight::new(weight).ok_or("VoterWeight only takes non-zero values.")
128	}
129}
finality_grandpa/weights.rs

finality_grandpa/
weights.rs
