solana-program-examples/tokens/pda-mint-authority/native/program/src/processor.rs

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

use crate::instructions::{
    create::{create_token, CreateTokenArgs},
    init::init,
    mint::mint_to,
};

#[derive(BorshSerialize, BorshDeserialize, Debug)]
enum MyInstruction {
    Init,
    Create(CreateTokenArgs),
    Mint,
}

pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    let instruction = MyInstruction::try_from_slice(instruction_data)?;

    match instruction {
        MyInstruction::Init => init(program_id, accounts),
        MyInstruction::Create(args) => create_token(program_id, accounts, args),
        MyInstruction::Mint => mint_to(program_id, accounts),
    }
}