miraland_program/
feature.rs

1//! Runtime features.
2//!
3//! Runtime features provide a mechanism for features to be simultaneously activated across the
4//! network. Since validators may choose when to upgrade, features must remain dormant until a
5//! sufficient majority of the network is running a version that would support a given feature.
6//!
7//! Feature activation is accomplished by:
8//! 1. Activation is requested by the feature authority, who issues a transaction to create the
9//!    feature account. The newly created feature account will have the value of
10//!    `Feature::default()`
11//! 2. When the next epoch is entered the runtime will check for new activation requests and
12//!    active them.  When this occurs, the activation slot is recorded in the feature account
13
14use crate::{
15    account_info::AccountInfo, clock::Slot, instruction::Instruction, program_error::ProgramError,
16    pubkey::Pubkey, rent::Rent, system_instruction,
17};
18
19crate::declare_id!("Feature111111111111111111111111111111111111");
20
21#[derive(Default, Debug, Serialize, Deserialize, PartialEq, Eq)]
22pub struct Feature {
23    pub activated_at: Option<Slot>,
24}
25
26impl Feature {
27    pub const fn size_of() -> usize {
28        9 // see test_feature_size_of.
29    }
30
31    pub fn from_account_info(account_info: &AccountInfo) -> Result<Self, ProgramError> {
32        if *account_info.owner != id() {
33            return Err(ProgramError::InvalidAccountOwner);
34        }
35        bincode::deserialize(&account_info.data.borrow())
36            .map_err(|_| ProgramError::InvalidAccountData)
37    }
38}
39
40/// Activate a feature
41pub fn activate(feature_id: &Pubkey, funding_address: &Pubkey, rent: &Rent) -> Vec<Instruction> {
42    activate_with_lamports(
43        feature_id,
44        funding_address,
45        rent.minimum_balance(Feature::size_of()),
46    )
47}
48
49pub fn activate_with_lamports(
50    feature_id: &Pubkey,
51    funding_address: &Pubkey,
52    lamports: u64,
53) -> Vec<Instruction> {
54    vec![
55        system_instruction::transfer(funding_address, feature_id, lamports),
56        system_instruction::allocate(feature_id, Feature::size_of() as u64),
57        system_instruction::assign(feature_id, &id()),
58    ]
59}
60
61#[cfg(test)]
62mod test {
63    use {super::*, miraland_program::clock::Slot};
64
65    #[test]
66    fn test_feature_size_of() {
67        assert_eq!(Feature::size_of() as u64, {
68            let feature = Feature {
69                activated_at: Some(0),
70            };
71            bincode::serialized_size(&feature).unwrap()
72        });
73        assert!(
74            Feature::size_of() >= bincode::serialized_size(&Feature::default()).unwrap() as usize
75        );
76        assert_eq!(Feature::default(), Feature { activated_at: None });
77
78        let features = [
79            Feature {
80                activated_at: Some(0),
81            },
82            Feature {
83                activated_at: Some(Slot::MAX),
84            },
85        ];
86        for feature in &features {
87            assert_eq!(
88                Feature::size_of(),
89                bincode::serialized_size(feature).unwrap() as usize
90            );
91        }
92    }
93}
miraland_program/feature.rs

miraland_program/
feature.rs
