Struct ReadonlyView 

pub struct ReadonlyView { /* private fields */ }

An AccountView proven to be a non-signer, non-writable read-only account. Useful for cross-program reads where you explicitly want to prevent accidental mutation attempts.

Implementations

impl ReadonlyView

pub fn validate(view: AccountView) -> Result<Self, ProgramError>

Validate that the account is neither a signer nor writable.

pub fn as_view(&self) -> &AccountView

Access the underlying AccountView.

pub fn into_view(self) -> AccountView

Consume and return the inner AccountView.

Methods from Deref<Target = AccountView>

pub const SYSTEM_PROGRAM_ID: Address

pub fn address(&self) -> &Address

The account’s public key.

pub unsafe fn owner(&self) -> &Address

The owning program’s address.

Safety

The returned reference is invalidated if the account is assigned to a new owner or closed. The caller must ensure no concurrent mutation occurs.

pub fn is_signer(&self) -> bool

Whether this account signed the transaction.

pub fn is_writable(&self) -> bool

Whether this account is writable in the transaction.

pub fn executable(&self) -> bool

Whether this account contains an executable program.

pub fn data_len(&self) -> usize

Current data length in bytes.

pub fn resize_delta(&self) -> i32

Resize delta (difference between current and original data length).

pub fn lamports(&self) -> u64

Current lamport balance.

pub fn is_data_empty(&self) -> bool

Whether the account data is empty (data_len == 0).

pub fn set_lamports(&self, lamports: u64)

Set the lamport balance.

pub fn owned_by(&self, program: &Address) -> bool

Check whether this account is owned by the given program.

pub unsafe fn assign(&self, new_owner: &Address)

Assign a new owner.

Safety

The caller must ensure the account is writable and that ownership transfer is authorized by the current owner program.

pub fn is_borrowed(&self) -> bool

Whether the account data is currently borrowed (shared or exclusive).

pub fn is_borrowed_mut(&self) -> bool

Whether the account data is exclusively (mutably) borrowed.

pub fn check_borrow(&self) -> Result<(), ProgramError>

Check that the account can be shared-borrowed.

pub fn check_borrow_mut(&self) -> Result<(), ProgramError>

Check that the account can be exclusively borrowed.

pub unsafe fn borrow_unchecked(&self) -> &[u8]

Borrow account data without borrow tracking.

Safety

The caller must ensure no mutable borrow is active.

pub unsafe fn borrow_unchecked_mut(&self) -> &mut [u8]

Mutably borrow account data without borrow tracking.

Safety

The caller must ensure no other borrows (shared or exclusive) are active.

pub fn try_borrow(&self) -> Result<Ref<'_, [u8]>, ProgramError>

Try to obtain a shared borrow of the account data.

Returns Err(AccountBorrowFailed) if the data is exclusively borrowed.

pub fn try_borrow_mut(&self) -> Result<RefMut<'_, [u8]>, ProgramError>

Try to obtain an exclusive (mutable) borrow of the account data.

Returns Err(AccountBorrowFailed) if the data is already borrowed.

pub fn segment_ref<T: Pod>( &self, offset: u32, size: u32, ) -> Result<Ref<'_, T>, ProgramError>

Project a typed segment from account data with native borrow tracking.

pub unsafe fn segment_ref_unchecked<T: Pod>( &self, offset: u32, ) -> Result<Ref<'_, T>, ProgramError>

Acquire a shared segment borrow without size/bounds validation.

Safety

The caller must have already verified:

• offset + size_of::<T>() does not overflow
• offset + size_of::<T>() <= data_len()

pub fn segment_mut<T: Pod>( &self, offset: u32, size: u32, ) -> Result<RefMut<'_, T>, ProgramError>

Project a mutable typed segment from account data with native borrow tracking.

pub unsafe fn segment_mut_unchecked<T: Pod>( &self, offset: u32, ) -> Result<RefMut<'_, T>, ProgramError>

Acquire an exclusive segment borrow without size/bounds/writable validation.

Safety

The caller must have already verified:

• The account is writable
• offset + size_of::<T>() does not overflow
• offset + size_of::<T>() <= data_len()

pub unsafe fn raw_ref<T: Pod>(&self) -> Result<Ref<'_, T>, ProgramError>

Explicit raw typed read of the account buffer.

pub unsafe fn raw_mut<T: Pod>(&self) -> Result<RefMut<'_, T>, ProgramError>

Explicit raw typed write of the account buffer.

pub fn resize(&self, new_len: usize) -> Result<(), ProgramError>

Resize the account data to new_len bytes.

Returns Err(InvalidRealloc) if the new length exceeds the permitted increase from the original allocation.

pub unsafe fn resize_unchecked(&self, new_len: usize)

Resize without bounds checking.

Safety

The caller must guarantee new_len <= original_len + MAX_PERMITTED_DATA_INCREASE.

pub fn close(&self) -> ProgramResult

Close the account: zero lamports and data, reassign owner to the System Program.

Caveat

This low-level routine does not verify the caller has authority to close the account, Solana’s runtime enforces owner/writable rules at transaction commit time regardless, but higher-level APIs (e.g. hopper_runtime::AccountView::close_to) should pre-check those rules. See account.rs::close_to for the safe wrapper.

pub unsafe fn close_unchecked(&self)

Close without borrow checks.

Safety

The caller must ensure no active borrows exist.

pub fn account_ptr(&self) -> *const RuntimeAccount

Raw pointer to the RuntimeAccount header.

pub fn require_signer(&self) -> ProgramResult

Validate that this account is a signer, returning a typed error.

pub fn require_writable(&self) -> ProgramResult

Validate that this account is writable.

pub fn require_owned_by(&self, program: &Address) -> ProgramResult

Validate that this account is owned by the given program.

pub fn require_payer(&self) -> ProgramResult

Validate signer + writable (common “payer” pattern).

pub fn disc(&self) -> u8

Read the Hopper account discriminator (first byte of data).

Returns 0 if the account has no data.

pub fn version(&self) -> u8

Read the Hopper account version (second byte of data).

Returns 0 if the account has fewer than 2 bytes.

pub fn layout_id(&self) -> Option<&[u8; 8]>

Read the 8-byte layout_id from the Hopper account header (bytes 4..12 of account data, per the canonical header format).

Returns None if the account has fewer than 12 bytes.

pub fn require_disc(&self, expected: u8) -> ProgramResult

Verify that this account has the given discriminator.

pub fn check_signer(&self) -> Result<&Self, ProgramError>

Chainable signer check.

pub fn check_writable(&self) -> Result<&Self, ProgramError>

Chainable writable check.

pub fn check_owned_by(&self, program: &Address) -> Result<&Self, ProgramError>

Chainable ownership check.

pub fn check_disc(&self, expected: u8) -> Result<&Self, ProgramError>

Chainable discriminator check.

pub fn check_has_data(&self) -> Result<&Self, ProgramError>

Chainable non-empty data check.

pub fn check_executable(&self) -> Result<&Self, ProgramError>

Chainable executable check.

pub fn check_address(&self, expected: &Address) -> Result<&Self, ProgramError>

Chainable address check.

pub fn check_data_len(&self, min_len: usize) -> Result<&Self, ProgramError>

Chainable minimum data length check.

pub fn read_owner(&self) -> Address

Read the owner address as a copy (32-byte value).

Unlike owner() (which is unsafe due to reference invalidation if assign() is called), this returns a copy that is always safe. Costs 32 bytes of stack space but eliminates aliasing hazards.

pub fn flags(&self) -> u8

Pack the account’s boolean flags into a single byte for fast comparison.

Bit layout:

• bit 0: is_signer
• bit 1: is_writable
• bit 2: executable
• bit 3: has data (data_len > 0)

Use with expect_flags() for single-instruction multi-check:

// Require: signer + writable + has data
account.expect_flags(0b1011)?;

pub fn expect_flags(&self, required: u8) -> ProgramResult

Check that the account’s flags contain all the required bits.

required is a bitmask of flags that must be set. See flags().

Trait Implementations

impl Clone for ReadonlyView

fn clone(&self) -> ReadonlyView

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Deref for ReadonlyView

type Target = AccountView

The resulting type after dereferencing.

fn deref(&self) -> &AccountView

Dereferences the value.

impl PartialEq for ReadonlyView

fn eq(&self, other: &ReadonlyView) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for ReadonlyView

impl StructuralPartialEq for ReadonlyView