Function process_write

programs/asset/program/src/processor/write.rs:28–162

Writes data to an extension. ### Accounts: 0. `[writable, signer]` asset 1. `[writable, signer]` payer 2. `[optional]` system_program

(
    program_id: &Pubkey,
    ctx: Context<Write>,
    data: DataInput,
)

///   1. `[writable, signer]` payer
///   2. `[optional]` system_program
pub(crate) fn process_write(
    program_id: &Pubkey,
    ctx: Context<Write>,
    data: DataInput,
) -> ProgramResult {
    // account validation

    require!(
        ctx.accounts.system_program.key() == &system_program::ID,
        ProgramError::IncorrectProgramId,
        "system_program"
    );

    require!(
        ctx.accounts.payer.is_signer(),
        ProgramError::MissingRequiredSignature,
        "payer"
    );

    require!(
        ctx.accounts.asset.is_signer(),
        ProgramError::MissingRequiredSignature,
        "asset"
    );

    require!(
        ctx.accounts.asset.owner() == program_id,
        ProgramError::IllegalOwner,
        "asset"
    );

    let asset_data = ctx.accounts.asset.try_borrow_data()?;

    require!(
        asset_data.len() >= Asset::LEN,
        AssetError::InvalidAccountLength,
        "asset"
    );

    // make sure that the asset is not already initialized
    require!(
        asset_data[0] == Discriminator::Uninitialized.into(),
        AssetError::AlreadyInitialized,
        "asset"
    );

    // determine the account offset

    let (extension, offset) =
        Asset::last_extension(&asset_data).ok_or(AssetError::ExtensionNotFound)?;
    let current = extension.extension_type();
    let expected = offset.saturating_add(extension.length() as usize);
    let boundary = extension.boundary();
    // the length of the account cannot be larger than the current extension length,
    // otherwise we would be writting data to an extension that does not exist
    if expected < asset_data.len() {
        return err!(AssetError::InvalidAccountLength);
    }