Struct pgx::datum::Internal

pub struct Internal(_);

Represents Postgres’ internal data type, which is documented as:

The internal pseudo-type is used to declare functions that are meant only to be called internally by the database system, and not by direct invocation in an SQL query. If a function has at least one internal-type argument then it cannot be called from SQL. To preserve the type safety of this restriction it is important to follow this coding rule: do not create any function that is declared to return internal unless it has at least one internal argument.

Implementation Notes

Internal is a wrapper around an Option<pg_sys::Datum>, which when retreived via ::get/get_mut() is cast to a pointer of T, returning the respective reference.

Safety

We make no guarantees about what the internal pg_sys::Datum actually points to in memory, so it is your responsibility to ensure that what you’re casting it to is really what it is.

Implementations

impl Internal

pub fn new<T>(t: T) -> Self

Construct a new Internal from any type.

The value will be dropped when the PgMemoryContexts::CurrentMemoryContext is deleted.

pub fn initialized(&self) -> bool

Returns true if the internal value is initialized. If false, this is a null pointer.

pub unsafe fn get<T>(&self) -> Option<&T>

Return a reference to the memory pointed to by this Internal, as Some(&T), unless the backing datum is null, then None.

Safety

We cannot guarantee that the contained datum points to memory that is really T. This is your responsibility.

pub unsafe fn insert<T>(&mut self, value: T) -> &mut T

Initializes the internal with value, then returns a mutable reference to it.

If the Internal is already initialized with a value, the old value is dropped.

See also Internal::get_or_insert, which doesn’t update the value if already initialized.

Safety

We cannot guarantee that the contained datum points to memory that is really T. This is your responsibility.

pub unsafe fn get_mut<T>(&self) -> Option<&mut T>

Return a reference to the memory pointed to by this Internal, as Some(&mut T), unless the backing datum is null, then None.

Safety

We cannot guarantee that the contained datum points to memory that is really T. This is your responsibility.

pub unsafe fn get_or_insert<T>(&mut self, value: T) -> &mut T

Initializes the internal with value if it is not initialized, then returns a mutable reference to the contained value.

See also Internal::insert, which updates the value even if the option already contains Some.

Safety

We cannot guarantee that the contained datum points to memory that is really T. This is your responsibility.

pub unsafe fn get_or_insert_default<T>(&mut self) -> &mut T where
    T: Default, 

Initializes the internal with a default if it is not initialized, then returns a mutable reference to the contained value.

See also Internal::insert, which updates the value even if the option already contains Some.

Safety

We cannot guarantee that the contained datum points to memory that is really T. This is your responsibility.

pub unsafe fn get_or_insert_with<F, T>(&mut self, f: F) -> &mut T where
    F: FnOnce() -> T, 

Inserts a value computed from f into the internal if it is None, then returns a mutable reference to the contained value.

Safety

We cannot guarantee that the contained datum points to memory that is really T. This is your responsibility.

pub fn unwrap(self) -> Option<Datum>

Returns the contained Option<pg_sys::Datum>

Trait Implementations

impl Default for Internal

fn default() -> Internal

Returns the “default value” for a type.

impl From<Option<usize>> for Internal

fn from(datum: Option<Datum>) -> Self

Performs the conversion.

impl FromDatum for Internal

unsafe fn from_datum(datum: Datum, is_null: bool, _: Oid) -> Option<Internal>

Safety

const NEEDS_TYPID: bool

unsafe fn from_datum_in_memory_context(
    memory_context: PgMemoryContexts,
    datum: Datum,
    is_null: bool,
    typoid: Oid
) -> Option<Self> where
    Self: Sized, 

Default implementation switched to the specified memory context and then simply calls From::from_datum(...) from within that context.

impl IntoDatum for Internal

fn into_datum(self) -> Option<Datum>

fn type_oid() -> Oid

fn array_type_oid() -> Oid