lib.rs

use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program_error::ProgramError,
    pubkey::Pubkey,
};

/// Define the type of state stored in accounts
#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct Counter {
    pub counter: u64,
}

#[macro_export]
macro_rules! compute_fn {
    ($msg:expr=> $($tt:tt)*) => {
        ::solana_program::msg!(concat!($msg, " {"));
        ::solana_program::log::sol_log_compute_units();
        let res = { $($tt)* };
        ::solana_program::log::sol_log_compute_units();
        ::solana_program::msg!(concat!(" } // ", $msg));
        res
    };
}

// Declare and export the program's entrypoint
entrypoint!(process_instruction);

// Empty 240 CU
// Without Logging 296 CU
// With Logging count 841 CU
// With tracking 2,886 CU
pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo], // Only contains the counter account
    _instruction_data: &[u8], // Only one instruction so we can ignore the rest
) -> ProgramResult {
    let account;

    // 102 CU
    compute_fn!("Get Account Info" => {
        let accounts_iter = &mut accounts.iter();
        account = next_account_info(accounts_iter)?;
    });

    // 103 CU
    compute_fn!("Do a signer check" => {
        if !account.is_signer {
            panic!("Account {} must be a signer", account.is_signer);
        }
    });

    // 116 CU
    compute_fn!("Owner Check " => {
        if account.owner != program_id {
            msg!("Greeted account does not have the correct program id");
            return Err(ProgramError::IncorrectProgramId);
        }
    });

    let mut greeting_account;

    // 128 CU
    compute_fn!("Load account data, increase and serialize " => {
        // Increment and store the number of times the account has been greeted
        greeting_account = Counter::try_from_slice(&account.data.borrow())?;
        greeting_account.counter += 1;
        greeting_account.serialize(&mut *account.data.borrow_mut())?;
    });

    // 645 CU
    compute_fn!("Logging " => {
        msg!("Greeted {} time(s)!", greeting_account.counter);
    });

    Ok(())
}