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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

//! Type validating that the account is one of a set of given Programs

use crate::accounts::program::Program;
use crate::error::{Error, ErrorCode};
use crate::{
    AccountDeserialize, Accounts, AccountsExit, CheckId, Key, Result, ToAccountInfos,
    ToAccountMetas,
};
use solana_program::account_info::AccountInfo;
use solana_program::instruction::AccountMeta;
use solana_program::pubkey::Pubkey;
use std::collections::BTreeSet;
use std::ops::Deref;

/// Type validating that the account is one of a set of given Programs
///
/// The `Interface` wraps over the [`Program`](crate::Program), allowing for
/// multiple possible program ids. Useful for any program that implements an
/// instruction interface. For example, spl-token and spl-token-2022 both implement
/// the spl-token interface.
///
/// # Table of Contents
/// - [Basic Functionality](#basic-functionality)
/// - [Out of the Box Types](#out-of-the-box-types)
///
/// # Basic Functionality
///
/// Checks:
///
/// - `expected_programs.contains(account_info.key)`
/// - `account_info.executable == true`
///
/// # Example
/// ```ignore
/// #[program]
/// mod my_program {
///     fn set_admin_settings(...){...}
/// }
///
/// #[account]
/// #[derive(Default)]
/// pub struct AdminSettings {
///     ...
/// }
///
/// #[derive(Accounts)]
/// pub struct SetAdminSettings<'info> {
///     #[account(mut, seeds = [b"admin"], bump)]
///     pub admin_settings: Account<'info, AdminSettings>,
///     #[account(constraint = program.programdata_address()? == Some(program_data.key()))]
///     pub program: Interface<'info, MyProgram>,
///     #[account(constraint = program_data.upgrade_authority_address == Some(authority.key()))]
///     pub program_data: Account<'info, ProgramData>,
///     pub authority: Signer<'info>,
/// }
/// ```
/// The given program has a function with which the upgrade authority can set admin settings.
///
/// The required constraints are as follows:
///
/// - `program` is the account of the program itself.
/// Its constraint checks that `program_data` is the account that contains the program's upgrade authority.
/// Implicitly, this checks that `program` is a BPFUpgradeable program (`program.programdata_address()?`
/// will be `None` if it's not).
/// - `program_data`'s constraint checks that its upgrade authority is the `authority` account.
/// - Finally, `authority` needs to sign the transaction.
///
/// # Out of the Box Types
///
/// Between the [`anchor_lang`](https://docs.rs/anchor-lang/latest/anchor_lang) and [`anchor_spl`](https://docs.rs/anchor_spl/latest/anchor_spl) crates,
/// the following `Interface` types are provided out of the box:
///
/// - [`TokenInterface`](https://docs.rs/anchor-spl/latest/anchor_spl/token_interface/struct.TokenInterface.html)
///
#[derive(Clone)]
pub struct Interface<'info, T>(Program<'info, T>);
impl<'a, T> Interface<'a, T> {
    pub(crate) fn new(info: &'a AccountInfo<'a>) -> Self {
        Self(Program::new(info))
    }
    pub fn programdata_address(&self) -> Result<Option<Pubkey>> {
        self.0.programdata_address()
    }
}
impl<'a, T: CheckId> TryFrom<&'a AccountInfo<'a>> for Interface<'a, T> {
    type Error = Error;
    /// Deserializes the given `info` into a `Program`.
    fn try_from(info: &'a AccountInfo<'a>) -> Result<Self> {
        T::check_id(info.key)?;
        if !info.executable {
            return Err(ErrorCode::InvalidProgramExecutable.into());
        }
        Ok(Self::new(info))
    }
}
impl<'info, T> Deref for Interface<'info, T> {
    type Target = AccountInfo<'info>;
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}
impl<'info, T> AsRef<AccountInfo<'info>> for Interface<'info, T> {
    fn as_ref(&self) -> &AccountInfo<'info> {
        &self.0
    }
}

impl<'info, B, T: CheckId> Accounts<'info, B> for Interface<'info, T> {
    #[inline(never)]
    fn try_accounts(
        _program_id: &Pubkey,
        accounts: &mut &'info [AccountInfo<'info>],
        _ix_data: &[u8],
        _bumps: &mut B,
        _reallocs: &mut BTreeSet<Pubkey>,
    ) -> Result<Self> {
        if accounts.is_empty() {
            return Err(ErrorCode::AccountNotEnoughKeys.into());
        }
        let account = &accounts[0];
        *accounts = &accounts[1..];
        Self::try_from(account)
    }
}

impl<'info, T> ToAccountMetas for Interface<'info, T> {
    fn to_account_metas(&self, is_signer: Option<bool>) -> Vec<AccountMeta> {
        self.0.to_account_metas(is_signer)
    }
}

impl<'info, T> ToAccountInfos<'info> for Interface<'info, T> {
    fn to_account_infos(&self) -> Vec<AccountInfo<'info>> {
        self.0.to_account_infos()
    }
}

impl<'info, T: AccountDeserialize> AccountsExit<'info> for Interface<'info, T> {}

impl<'info, T: AccountDeserialize> Key for Interface<'info, T> {
    fn key(&self) -> Pubkey {
        self.0.key()
    }
}