cbe_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::InvalidArgument);
34        }
35        bincode::deserialize(&account_info.data.borrow()).map_err(|_| ProgramError::InvalidArgument)
36    }
37}
38
39/// Activate a feature
40pub fn activate(feature_id: &Pubkey, funding_address: &Pubkey, rent: &Rent) -> Vec<Instruction> {
41    activate_with_scoobies(
42        feature_id,
43        funding_address,
44        rent.minimum_balance(Feature::size_of()),
45    )
46}
47
48pub fn activate_with_scoobies(
49    feature_id: &Pubkey,
50    funding_address: &Pubkey,
51    scoobies: u64,
52) -> Vec<Instruction> {
53    vec![
54        system_instruction::transfer(funding_address, feature_id, scoobies),
55        system_instruction::allocate(feature_id, Feature::size_of() as u64),
56        system_instruction::assign(feature_id, &id()),
57    ]
58}
59
60#[cfg(test)]
61mod test {
62    use {super::*, cbe_program::clock::Slot};
63
64    #[test]
65    fn test_feature_size_of() {
66        assert_eq!(Feature::size_of() as u64, {
67            let feature = Feature {
68                activated_at: Some(0),
69            };
70            bincode::serialized_size(&feature).unwrap()
71        });
72        assert!(
73            Feature::size_of() >= bincode::serialized_size(&Feature::default()).unwrap() as usize
74        );
75        assert_eq!(Feature::default(), Feature { activated_at: None });
76
77        let features = [
78            Feature {
79                activated_at: Some(0),
80            },
81            Feature {
82                activated_at: Some(Slot::MAX),
83            },
84        ];
85        for feature in &features {
86            assert_eq!(
87                Feature::size_of(),
88                bincode::serialized_size(feature).unwrap() as usize
89            );
90        }
91    }
92}
cbe_program/feature.rs

cbe_program/
feature.rs
