74 lines
2.1 KiB
Rust
74 lines
2.1 KiB
Rust
//! counter is an example program that depends on an external interface
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//! that another program (here counter-auth/src/lib.rs) must implement. This allows
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//! our program to depend on another program, without knowing anything about it
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//! other than that it implements the `Auth` trait.
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//!
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//! Here, we have a counter, where, in order to set the count, the `Auth`
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//! program must first approve the transaction.
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use anchor_lang::prelude::*;
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declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");
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#[program]
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pub mod counter {
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use super::*;
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#[state]
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pub struct Counter {
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pub count: u64,
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pub auth_program: Pubkey,
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}
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impl Counter {
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pub fn new(_ctx: Context<Empty>, auth_program: Pubkey) -> Result<Self> {
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Ok(Self {
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count: 0,
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auth_program,
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})
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}
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#[access_control(SetCount::accounts(&self, &ctx))]
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pub fn set_count(&mut self, ctx: Context<SetCount>, new_count: u64) -> Result<()> {
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// Ask the auth program if we should approve the transaction.
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let cpi_program = ctx.accounts.auth_program.clone();
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let cpi_ctx = CpiContext::new(cpi_program, Empty {});
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auth::is_authorized(cpi_ctx, self.count, new_count)?;
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// Approved, so update.
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self.count = new_count;
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Ok(())
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}
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}
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}
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#[derive(Accounts)]
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pub struct Empty {}
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#[derive(Accounts)]
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pub struct SetCount<'info> {
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auth_program: AccountInfo<'info>,
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}
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impl<'info> SetCount<'info> {
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// Auxiliary account validation requiring program inputs. As a convention,
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// we separate it from the business logic of the instruction handler itself.
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pub fn accounts(counter: &Counter, ctx: &Context<SetCount>) -> Result<()> {
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if ctx.accounts.auth_program.key != &counter.auth_program {
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return err!(ErrorCode::InvalidAuthProgram);
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}
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Ok(())
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}
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}
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#[interface]
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pub trait Auth<'info, T: Accounts<'info>> {
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fn is_authorized(ctx: Context<T>, current: u64, new: u64) -> Result<()>;
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}
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#[error_code]
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pub enum ErrorCode {
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#[msg("Invalid auth program.")]
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InvalidAuthProgram,
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}
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