State

State is the data stored on Solana accounts.

Notice that the term state is used to describe the data stored on Solana accounts, while the term account is used to describe the Solana account itself.

Define Custom State Accounts

In TypeScript, custom state accounts are defined as an Interface that extends Account.

import { Account, Pubkey, u64, u8 } from "@solanaturbine/poseidon";

export interface EscrowState extends Account {
  maker: Pubkey;
  makerMint: Pubkey;
  takerMint: Pubkey;
  amount: u64;
  seed: u64;
  authBump: u8;
  escrowBump: u8;
  vaultBump: u8;
}

You can use types from the @solanaturbine/poseidon package to define the fields of the custom state account.

After transpiling, the custom state account will be defined as a struct in Rust.

#[account]
pub struct EscrowState {
    pub maker: Pubkey,
    pub maker_mint: Pubkey,
    pub taker_mint: Pubkey,
    pub amount: u64,
    pub seed: u64,
    pub auth_bump: u8,
    pub escrow_bump: u8,
    pub vault_bump: u8,
}

State Manipulation

To set the state of an account, you can simply assign the values to the fields of the account.

// ...

export default class EscrowProgram {
  static PROGRAM_ID = new Pubkey("11111111111111111111111111111111");
  make(
    maker: Signer,
    escrow: EscrowState,
    makerAta: AssociatedTokenAccount,
    makerMint: Mint,
    takerMint: Mint,
    auth: UncheckedAccount,
    vault: TokenAccount,
    depositAmount: u64,
    offerAmount: u64,
    seed: u64
  ) {
    escrow.maker = maker.key;
    escrow.makerMint = makerMint.key;
    escrow.takerMint = takerMint.key;

    escrow.amount = offerAmount;
    escrow.seed = seed;
  }
}

The corresponding Rust code will be generated as follows.

// ...

declare_id!("11111111111111111111111111111111");
#[program]
pub mod escrow_program {
    use super::*;
    pub fn make(
        ctx: Context<MakeContext>,
        deposit_amount: u64,
        offer_amount: u64,
        seed: u64,
    ) -> Result<()> {
        ctx.accounts.escrow.maker = ctx.accounts.maker.key();
        ctx.accounts.escrow.maker_mint = ctx.accounts.maker_mint.key();
        ctx.accounts.escrow.taker_mint = ctx.accounts.taker_mint.key();

        ctx.accounts.escrow.amount = offer_amount;
        ctx.accounts.escrow.seed = seed;
    }
}

Also if you want to do some arithmetic operations, @solanaturbine/poseidon package provides the necessary types for that.

Check out vote example to see how to use them. Here's a snippet from the example:

// initialize the state
state.vote = new i64(0);
// increment the state
state.vote = state.vote.add(1);
// decrement the state
state.vote = state.vote.sub(1);

Poseidon Type Reference

where N is the max length of the type.