token/p-token/src/processor/get_account_data_size.rs

use {
    super::check_account_owner,
    pinocchio::{
        account_info::AccountInfo, program::set_return_data, program_error::ProgramError,
        ProgramResult,
    },
    spl_token_interface::{
        error::TokenError,
        state::{account::Account, load, mint::Mint, Transmutable},
    },
};

#[inline(always)]
pub fn process_get_account_data_size(accounts: &[AccountInfo]) -> ProgramResult {
    let [mint_info, _remaining @ ..] = accounts else {
        return Err(ProgramError::NotEnoughAccountKeys);
    };

    // Make sure the mint is valid.
    check_account_owner(mint_info)?;

    // SAFETY: single immutable borrow to `mint_info` account data and
    // `load` validates that the mint is initialized.
    let _ = unsafe {
        load::<Mint>(mint_info.borrow_data_unchecked()).map_err(|_| TokenError::InvalidMint)?
    };

    set_return_data(&Account::LEN.to_le_bytes());

    Ok(())
}