47 lines
1.7 KiB
Rust
47 lines
1.7 KiB
Rust
// Copyright (C) Parity Technologies (UK) Ltd.
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// This file is part of Pezkuwi.
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// Pezkuwi is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Pezkuwi is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Pezkuwi. If not, see <http://www.gnu.org/licenses/>.
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//! XCM utils for internal use.
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use crate::MAX_INSTRUCTIONS_TO_DECODE;
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use alloc::vec::Vec;
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use codec::{decode_vec_with_len, Compact, Decode};
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environmental::environmental!(instructions_count: u8);
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/// Decode a `vec` of XCM instructions.
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///
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/// This function keeps track of nested XCM instructions and enforces a total limit of
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/// `MAX_INSTRUCTIONS_TO_DECODE`.
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pub fn decode_xcm_instructions<I: codec::Input, T: Decode>(
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input: &mut I,
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) -> Result<Vec<T>, codec::Error> {
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instructions_count::using_once(&mut 0, || {
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let vec_len: u32 = <Compact<u32>>::decode(input)?.into();
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instructions_count::with(|count| {
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*count = count.saturating_add(vec_len as u8);
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if *count > MAX_INSTRUCTIONS_TO_DECODE {
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return Err(codec::Error::from("Max instructions exceeded"));
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}
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Ok(())
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})
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.unwrap_or(Err(codec::Error::from("Error calling `instructions_count::with()`")))?;
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let decoded_instructions = decode_vec_with_len(input, vec_len as usize)?;
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Ok(decoded_instructions)
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})
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}
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