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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121

// Copyright (C) 2019-2023 Aleo Systems Inc.
// This file is part of the snarkVM library.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use super::*;

impl<N: Network> Metadata<N> {
    /// Initializes the genesis metadata.
    pub fn genesis() -> Result<Self> {
        // Prepare a genesis metadata.
        let network = N::ID;
        let round = 0;
        let height = 0;
        let cumulative_weight = 0;
        let cumulative_proof_target = 0;
        let coinbase_target = N::GENESIS_COINBASE_TARGET;
        let proof_target = N::GENESIS_PROOF_TARGET;
        let last_coinbase_target = N::GENESIS_COINBASE_TARGET;
        let last_coinbase_timestamp = N::GENESIS_TIMESTAMP;
        let timestamp = N::GENESIS_TIMESTAMP;

        // Return the genesis metadata.
        Self::new(
            network,
            round,
            height,
            cumulative_weight,
            cumulative_proof_target,
            coinbase_target,
            proof_target,
            last_coinbase_target,
            last_coinbase_timestamp,
            timestamp,
        )
    }

    /// Returns `true` if the metadata is a genesis metadata.
    pub fn is_genesis(&self) -> bool {
        // Ensure the network ID is correct.
        self.network == N::ID
            // Ensure the round in the genesis block is 0.
            && self.round == 0u64
            // Ensure the height in the genesis block is 0.
            && self.height == 0u32
            // Ensure the cumulative weight in the genesis block is 0.
            && self.cumulative_weight == 0u128
            // Ensure the cumulative proof target in the genesis block is 0.
            && self.cumulative_proof_target == 0u128
            // Ensure the coinbase target in the genesis block is `GENESIS_COINBASE_TARGET`.
            && self.coinbase_target == N::GENESIS_COINBASE_TARGET
            // Ensure the proof target in the genesis block is `GENESIS_PROOF_TARGET`.
            && self.proof_target == N::GENESIS_PROOF_TARGET
            // Ensure the last coinbase target in the genesis block is `GENESIS_COINBASE_TARGET`.
            && self.last_coinbase_target == N::GENESIS_COINBASE_TARGET
            // Ensure the last coinbase timestamp in the genesis block is `GENESIS_TIMESTAMP`.
            && self.last_coinbase_timestamp == N::GENESIS_TIMESTAMP
            // Ensure the timestamp in the genesis block is `GENESIS_TIMESTAMP`.
            && self.timestamp == N::GENESIS_TIMESTAMP
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use console::network::Testnet3;

    type CurrentNetwork = Testnet3;

    /// Returns the expected metadata size by summing its subcomponent sizes.
    /// Update this method if the contents of the metadata have changed.
    fn get_expected_size() -> usize {
        // Metadata size.
        1 + 8 + 4 + 16 + 16 + 8 + 8 + 8 + 8 + 8
            // Add an additional 2 bytes for versioning.
            + 2
    }

    #[test]
    fn test_genesis_metadata_size() {
        let rng = &mut TestRng::default();

        // Prepare the expected size.
        let expected_size = get_expected_size();
        // Prepare the genesis metadata.
        let genesis_metadata = crate::header::metadata::test_helpers::sample_block_metadata(rng);
        // Ensure the size of the genesis metadata is correct.
        assert_eq!(expected_size, genesis_metadata.to_bytes_le().unwrap().len());
    }

    #[test]
    fn test_genesis_metadata() {
        let rng = &mut TestRng::default();

        // Prepare the genesis metadata.
        let metadata = crate::header::metadata::test_helpers::sample_block_metadata(rng);
        // Ensure the metadata is a genesis metadata.
        assert!(metadata.is_genesis());

        // Ensure the genesis block contains the following.
        assert_eq!(metadata.network(), CurrentNetwork::ID);
        assert_eq!(metadata.round(), 0);
        assert_eq!(metadata.height(), 0);
        assert_eq!(metadata.cumulative_weight(), 0);
        assert_eq!(metadata.cumulative_proof_target(), 0);
        assert_eq!(metadata.coinbase_target(), CurrentNetwork::GENESIS_COINBASE_TARGET);
        assert_eq!(metadata.proof_target(), CurrentNetwork::GENESIS_PROOF_TARGET);
        assert_eq!(metadata.last_coinbase_target(), CurrentNetwork::GENESIS_COINBASE_TARGET);
        assert_eq!(metadata.last_coinbase_timestamp(), CurrentNetwork::GENESIS_TIMESTAMP);
        assert_eq!(metadata.timestamp(), CurrentNetwork::GENESIS_TIMESTAMP);
    }
}