Struct anchor_lang::accounts::account_loader::AccountLoader

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pub struct AccountLoader<'info, T: ZeroCopy + Owner> { /* private fields */ }
Expand description

Type facilitating on demand zero copy deserialization.

Note that using accounts in this way is distinctly different from using, for example, the Account. Namely, one must call

  • load_init after initializing an account (this will ignore the missing account discriminator that gets added only after the user’s instruction code)
  • load when the account is not mutable
  • load_mut when the account is mutable

For more details on zero-copy-deserialization, see the account attribute.

⚠️ When using this type it's important to be mindful of any calls to the load functions so as not to induce a RefCell panic, especially when sharing accounts across CPI boundaries. When in doubt, one should make sure all refs resulting from a call to a load function are dropped before CPI. This can be done explicitly by calling drop(my_var) or implicitly by wrapping the code using the Ref in braces {..} or moving it into its own function.

§Example

use anchor_lang::prelude::*;

declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");

#[program]
pub mod bar {
    use super::*;

    pub fn create_bar(ctx: Context<CreateBar>, data: u64) -> Result<()> {
        let bar = &mut ctx.accounts.bar.load_init()?;
        bar.authority = ctx.accounts.authority.key();
        bar.data = data;
        Ok(())
    }

    pub fn update_bar(ctx: Context<UpdateBar>, data: u64) -> Result<()> {
        (*ctx.accounts.bar.load_mut()?).data = data;
        Ok(())
    }
}

#[account(zero_copy)]
#[derive(Default)]
pub struct Bar {
    authority: Pubkey,
    data: u64
}

#[derive(Accounts)]
pub struct CreateBar<'info> {
    #[account(
        init,
        payer = authority
    )]
    bar: AccountLoader<'info, Bar>,
    #[account(mut)]
    authority: Signer<'info>,
    system_program: AccountInfo<'info>,
}

#[derive(Accounts)]
pub struct UpdateBar<'info> {
    #[account(
        mut,
        has_one = authority,
    )]
    pub bar: AccountLoader<'info, Bar>,
    pub authority: Signer<'info>,
}

Implementations§

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impl<'info, T: ZeroCopy + Owner> AccountLoader<'info, T>

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pub fn try_from( acc_info: &'info AccountInfo<'info>, ) -> Result<AccountLoader<'info, T>>

Constructs a new Loader from a previously initialized account.

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pub fn try_from_unchecked( _program_id: &Pubkey, acc_info: &'info AccountInfo<'info>, ) -> Result<AccountLoader<'info, T>>

Constructs a new Loader from an uninitialized account.

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pub fn load(&self) -> Result<Ref<'_, T>>

Returns a Ref to the account data structure for reading.

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pub fn load_mut(&self) -> Result<RefMut<'_, T>>

Returns a RefMut to the account data structure for reading or writing.

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pub fn load_init(&self) -> Result<RefMut<'_, T>>

Returns a RefMut to the account data structure for reading or writing. Should only be called once, when the account is being initialized.

Trait Implementations§

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impl<'info, B, T: ZeroCopy + Owner> Accounts<'info, B> for AccountLoader<'info, T>

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fn try_accounts( _program_id: &Pubkey, accounts: &mut &'info [AccountInfo<'info>], _ix_data: &[u8], _bumps: &mut B, _reallocs: &mut BTreeSet<Pubkey>, ) -> Result<Self>

Returns the validated accounts struct. What constitutes “valid” is program dependent. However, users of these types should never have to worry about account substitution attacks. For example, if a program expects a Mint account from the SPL token program in a particular field, then it should be impossible for this method to return Ok if any other account type is given–from the SPL token program or elsewhere. Read more
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impl<'info, T: ZeroCopy + Owner> AccountsClose<'info> for AccountLoader<'info, T>

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fn close(&self, sol_destination: AccountInfo<'info>) -> Result<()>

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impl<'info, T: ZeroCopy + Owner> AccountsExit<'info> for AccountLoader<'info, T>

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fn exit(&self, program_id: &Pubkey) -> Result<()>

program_id is the currently executing program.
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impl<'info, T: ZeroCopy + Owner> AsRef<AccountInfo<'info>> for AccountLoader<'info, T>

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fn as_ref(&self) -> &AccountInfo<'info>

Converts this type into a shared reference of the (usually inferred) input type.
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impl<'info, T: Clone + ZeroCopy + Owner> Clone for AccountLoader<'info, T>

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fn clone(&self) -> AccountLoader<'info, T>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'info, T: ZeroCopy + Owner + Debug> Debug for AccountLoader<'info, T>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<'info, T: ZeroCopy + Owner> Key for AccountLoader<'info, T>

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fn key(&self) -> Pubkey

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impl<'info, T: ZeroCopy + Owner> ToAccountInfos<'info> for AccountLoader<'info, T>

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impl<'info, T: ZeroCopy + Owner> ToAccountMetas for AccountLoader<'info, T>

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fn to_account_metas(&self, is_signer: Option<bool>) -> Vec<AccountMeta>

is_signer is given as an optional override for the signer meta field. This covers the edge case when a program-derived-address needs to relay a transaction from a client to another program but sign the transaction before the relay. The client cannot mark the field as a signer, and so we have to override the is_signer meta field given by the client.

Auto Trait Implementations§

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impl<'info, T> Freeze for AccountLoader<'info, T>

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impl<'info, T> !RefUnwindSafe for AccountLoader<'info, T>

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impl<'info, T> !Send for AccountLoader<'info, T>

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impl<'info, T> !Sync for AccountLoader<'info, T>

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impl<'info, T> Unpin for AccountLoader<'info, T>

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impl<'info, T> !UnwindSafe for AccountLoader<'info, T>

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impl<T> AbiExample for T

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default fn example() -> T

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<'info, T> Lamports<'info> for T
where T: AsRef<AccountInfo<'info>>,

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fn get_lamports(&self) -> u64

Get the lamports of the account.
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fn add_lamports(&self, amount: u64) -> Result<&Self>

Add lamports to the account. Read more
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fn sub_lamports(&self, amount: u64) -> Result<&Self>

Subtract lamports from the account. Read more
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<'info, T> ToAccountInfo<'info> for T
where T: AsRef<AccountInfo<'info>>,

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V