pinocchio-memo-program 1.0.0

use {
    pinocchio::{
        entrypoint::{InstructionContext, MaybeAccount},
        error::ProgramError,
        ProgramResult,
    },
    solana_program_log::log,
};

/// Process a memo instruction.
///
/// This function processes a memo instruction by logging the public keys of the signers
/// (if any) and the memo data itself, checking if the required signatures are present;
/// when any required signature is missing, it returns `ProgramError::MissingRequiredSignature`
/// error.
pub fn process_instruction(mut context: InstructionContext) -> ProgramResult {
    let mut missing_required_signature = false;

    // Validates signer accounts (if any).

    if context.remaining() > 0 {
        // Logs a message indicating that there are signers.
        log!("Signed by:");

        while context.remaining() > 0 {
            // Duplicated accounts are implicitly checked since at least one of the
            // "copies" must be a signer.
            if let MaybeAccount::Account(account) = context.next_account()? {
                if account.is_signer() {
                    // SAFETY: Use the syscall to log the public key of the account.
                    #[cfg(any(target_os = "solana", target_arch = "bpf"))]
                    unsafe {
                        pinocchio::syscalls::sol_log_pubkey(account.address().as_array().as_ptr())
                    };
                } else {
                    missing_required_signature = true;
                }
            }
        }

        if missing_required_signature {
            return Err(ProgramError::MissingRequiredSignature);
        }
    }

    // SAFETY: All accounts have been processed.
    let instruction_data = unsafe { context.instruction_data_unchecked() };

    // Logs the length of the memo message and its content.
    log!("Memo (len {})", instruction_data.len());

    // SAFETY: The syscall will validate the UTF-8 encoding of the memo data.
    #[cfg(any(target_os = "solana", target_arch = "bpf"))]
    unsafe {
        pinocchio::syscalls::sol_log_(instruction_data.as_ptr(), instruction_data.len() as u64);
    }

    Ok(())
}