capnp/
constant.rs

1// Copyright (c) 2013-2017 Sandstorm Development Group, Inc. and contributors
2//
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4// of this software and associated documentation files (the "Software"), to deal
5// in the Software without restriction, including without limitation the rights
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7// copies of the Software, and to permit persons to whom the Software is
8// furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
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14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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19// THE SOFTWARE.
20
21//! Helper type for generated Struct and List constants.
22//!
23//! `constant::Reader` does not do bounds-checking, so it is unsafe to
24//! manually construct one of these.
25
26use core::marker::PhantomData;
27
28use crate::any_pointer;
29use crate::private::layout::PointerReader;
30use crate::traits::Owned;
31use crate::Result;
32
33#[derive(Copy, Clone)]
34pub struct Reader<T> {
35    pub(crate) phantom: PhantomData<T>,
36    pub(crate) arena: &'static crate::private::arena::GeneratedCodeArena,
37}
38
39impl<T> Reader<T>
40where
41    T: Owned,
42{
43    /// Constructs a new `constant::Reader`.
44    pub const fn new(arena: &'static crate::private::arena::GeneratedCodeArena) -> Self {
45        Self {
46            phantom: PhantomData,
47            arena,
48        }
49    }
50
51    /// Retrieve the value.
52    pub fn get(&self) -> Result<<T as Owned>::Reader<'static>> {
53        any_pointer::Reader::new(PointerReader::get_root_from_arena(self.arena)?).get_as()
54    }
55}
capnp/constant.rs

capnp/
constant.rs
