1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86

// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of Tetsy Vapory.

// Tetsy Vapory is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Tetsy Vapory is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Tetsy Vapory.  If not, see <http://www.gnu.org/licenses/>.

//! Trait for fetching chain data.

use std::sync::Arc;

use common_types::{
	header::Header,
	encoded,
	receipt::Receipt,
};
use enjen::{Engine, StateDependentProof};
use vapory_types::H256;
use futures::future::IntoFuture;

/// Provides full chain data.
pub trait ChainDataFetcher: Send + Sync + 'static {
	/// Error type when data unavailable.
	type Error: ::std::fmt::Debug;

	/// Future for fetching block body.
	type Body: IntoFuture<Item=encoded::Block, Error=Self::Error>;
	/// Future for fetching block receipts.
	type Receipts: IntoFuture<Item=Vec<Receipt>, Error=Self::Error>;
	/// Future for fetching epoch transition
	type Transition: IntoFuture<Item=Vec<u8>, Error=Self::Error>;

	/// Fetch a block body.
	fn block_body(&self, header: &Header) -> Self::Body;

	/// Fetch block receipts.
	fn block_receipts(&self, header: &Header) -> Self::Receipts;

	/// Fetch epoch transition proof at given header.
	fn epoch_transition(
		&self,
		_hash: H256,
		_engine: Arc<dyn Engine>,
		_checker: Arc<dyn StateDependentProof>
	) -> Self::Transition;
}

/// Fetcher implementation which cannot fetch anything.
pub struct Unavailable;

/// Create a fetcher which has all data unavailable.
pub fn unavailable() -> Unavailable { Unavailable }

impl ChainDataFetcher for Unavailable {
	type Error = &'static str;

	type Body = Result<encoded::Block, &'static str>;
	type Receipts = Result<Vec<Receipt>, &'static str>;
	type Transition = Result<Vec<u8>, &'static str>;

	fn block_body(&self, _header: &Header) -> Self::Body {
		Err("fetching block bodies unavailable")
	}

	fn block_receipts(&self, _header: &Header) -> Self::Receipts {
		Err("fetching block receipts unavailable")
	}

	fn epoch_transition(
		&self,
		_hash: H256,
		_engine: Arc<dyn Engine>,
		_checker: Arc<dyn StateDependentProof>
	) -> Self::Transition {
		Err("fetching epoch transition proofs unavailable")
	}
}