30 lines
1.2 KiB
Rust
30 lines
1.2 KiB
Rust
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// Copyright 2015-2018 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity 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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// Parity 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 Parity. If not, see <http://www.gnu.org/licenses/>.
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use ethcore::client::{Client, BlockChainClient, BlockId};
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use ethereum_types::H256;
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// TODO: Instead of a constant, make this based on consensus finality.
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/// Number of confirmations required before request can be processed.
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pub const REQUEST_CONFIRMATIONS_REQUIRED: u64 = 3;
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/// Get hash of the last block with at least n confirmations.
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pub fn get_confirmed_block_hash(client: &Client, confirmations: u64) -> Option<H256> {
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client.block_number(BlockId::Latest)
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.map(|b| b.saturating_sub(confirmations))
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.and_then(|b| client.block_hash(BlockId::Number(b)))
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}
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