gear_common/storage/primitives/
counted.rs

1// Copyright (C) Gear Technologies Inc.
2// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
3
4//! Module for counting primitive.
5//!
6//! Counting primitives are able to return the information
7//! about amount of elements they contain.
8
9/// Represents default counting logic, by providing ability
10/// to return length of the object as specified (associated) type
11/// or answer the question is the object empty.
12pub trait Counted {
13    /// Returning length type.
14    type Length: Default + PartialEq;
15
16    /// Returns current Self's amount of elements as `Length` type.
17    fn len() -> Self::Length;
18
19    /// Returns bool, defining if Self doesn't contain elements.
20    fn is_empty() -> bool {
21        Self::len() == Default::default()
22    }
23}
24
25/// Represents default counting logic, by providing ability
26/// to return length of the object as specified (associated) type
27/// or answer the question is the object empty, by provided key of
28/// specified (associated) type.
29///
30/// Should be implemented on double map based types.
31pub trait CountedByKey {
32    /// Key type of counting target.
33    type Key;
34    /// Returning length type.
35    type Length: Default + PartialEq;
36
37    /// Returns current Self's amount of elements as `Length` type.
38    fn len(key: &Self::Key) -> Self::Length;
39
40    /// Returns bool, defining if Self doesn't contain elements.
41    fn is_empty(key: &Self::Key) -> bool {
42        Self::len(key) == Default::default()
43    }
44}
gear_common/storage/primitives/counted.rs

gear_common/storage/primitives/
counted.rs
