Struct linera_views::views::queue_view::QueueView

pub struct QueueView<C, T> { /* private fields */ }

A view that supports a FIFO queue for values of type T.

Implementations

impl<'a, C, T> QueueView<C, T>

where C: Context + Send + Sync, ViewError: From<C::Error>, T: Send + Sync + Clone + Serialize + DeserializeOwned,

pub async fn front(&self) -> Result<Option<T>, ViewError>

Reads the front value, if any.

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(42);
assert_eq!(queue.front().await.unwrap(), Some(34));

pub async fn back(&self) -> Result<Option<T>, ViewError>

Reads the back value, if any.

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(42);
assert_eq!(queue.back().await.unwrap(), Some(42));

pub fn delete_front(&mut self)

Deletes the front value, if any.

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34 as u128);
queue.delete_front();
assert_eq!(queue.elements().await.unwrap(), Vec::<u128>::new());

pub fn push_back(&mut self, value: T)

Pushes a value to the end of the queue.

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(37);
assert_eq!(queue.elements().await.unwrap(), vec![34, 37]);

pub fn count(&self) -> usize

Reads the size of the queue.

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
assert_eq!(queue.count(), 1);

pub fn extra(&self) -> &C::Extra

Obtains the extra data.

pub async fn read_front(&self, count: usize) -> Result<Vec<T>, ViewError>

Reads the count next values in the queue (including staged ones).

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(42);
assert_eq!(queue.read_front(1).await.unwrap(), vec![34]);

pub async fn read_back(&self, count: usize) -> Result<Vec<T>, ViewError>

Reads the count last values in the queue (including staged ones).

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(42);
assert_eq!(queue.read_back(1).await.unwrap(), vec![42]);

pub async fn elements(&self) -> Result<Vec<T>, ViewError>

Reads all the elements

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(37);
assert_eq!(queue.elements().await.unwrap(), vec![34, 37]);

pub async fn iter_mut(&'a mut self) -> Result<IterMut<'a, T>, ViewError>

Gets a mutable iterator on the entries of the queue

let mut queue = QueueView::load(context).await.unwrap();
queue.push_back(34);
let mut iter = queue.iter_mut().await.unwrap();
let value = iter.next().unwrap();
*value = 42;
assert_eq!(queue.elements().await.unwrap(), vec![42]);

Trait Implementations

impl<C, T> ClonableView<C> for QueueView<C, T>

where C: Context + Send + Sync, ViewError: From<C::Error>, T: Clone + Send + Sync + Serialize,

fn clone_unchecked(&mut self) -> Result<Self, ViewError>

Creates a clone of this view, sharing the underlying storage context but prone to data races which can corrupt the view state.

impl<C, T> ContainerType for QueueView<C, T>

where C: Send + Sync + Context, T: Serialize + DeserializeOwned + Clone + Send + Sync + OutputType,

async fn resolve_field(&self, ctx: &Context<'_>) -> ServerResult<Option<Value>>

Resolves a field value and outputs it as a json value async_graphql::Value.

async fn find_entity( &self, ctx: &Context<'_>, params: &Value, ) -> ServerResult<Option<Value>>

Find the GraphQL entity with the given name from the parameter.

fn collect_all_fields<'a>( &'a self, ctx: &ContextBase<'a, &'a Positioned<SelectionSet>>, fields: &mut Fields<'a>, ) -> Result<(), ServerError>

where Self: Send + Sync,

Collect all the fields of the container that are queried in the selection set.

impl<C: Debug, T: Debug> Debug for QueueView<C, T>

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

Formats the value using the given formatter.

impl<C, T> HashableView<C> for QueueView<C, T>

where C: Context + Send + Sync, ViewError: From<C::Error>, T: Send + Sync + Clone + Serialize + DeserializeOwned,

type Hasher = CoreWrapper<Sha3_256Core>

How to compute hashes.

fn hash_mut<'life0, 'async_trait>( &'life0 mut self, ) -> Pin<Box<dyn Future<Output = Result<<Self::Hasher as Hasher>::Output, ViewError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Computes the hash of the values.

fn hash<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<<Self::Hasher as Hasher>::Output, ViewError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Computes the hash of the values.

impl<C, T> OutputType for QueueView<C, T>

where C: Send + Sync + Context, T: Serialize + DeserializeOwned + Clone + Send + Sync + OutputType,

fn type_name() -> Cow<'static, str>

Type the name.

fn create_type_info(registry: &mut Registry) -> String

Create type information in the registry and return qualified typename.

async fn resolve( &self, ctx: &ContextSelectionSet<'_>, _field: &Positioned<Field>, ) -> ServerResult<Value>

Resolve an output value to async_graphql::Value.

fn qualified_type_name() -> String

Qualified typename.

fn introspection_type_name(&self) -> Cow<'static, str>

Introspection type name

impl<C: Send + Sync, T: OutputType> TypeName for QueueView<C, T>

fn type_name() -> Cow<'static, str>

Returns a GraphQL type name.

impl<C, T> View<C> for QueueView<C, T>

where C: Context + Send + Sync, ViewError: From<C::Error>, T: Send + Sync + Serialize,

const NUM_INIT_KEYS: usize = 1usize

The number of keys used for the initialization

fn context(&self) -> &C

Obtains a mutable reference to the internal context.

fn pre_load(context: &C) -> Result<Vec<Vec<u8>>, ViewError>

Creates the keys needed for loading the view

fn post_load(context: C, values: &[Option<Vec<u8>>]) -> Result<Self, ViewError>

Loads a view from the values

fn load<'async_trait>( context: C, ) -> Pin<Box<dyn Future<Output = Result<Self, ViewError>> + Send + 'async_trait>>

where Self: 'async_trait,

Loads a view

fn rollback(&mut self)

Discards all pending changes. After that flush should have no effect to storage.

fn has_pending_changes<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = bool> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Returns true if flushing this view would result in changes to the persistent storage.

fn flush(&mut self, batch: &mut Batch) -> Result<bool, ViewError>

Persists changes to storage. This leaves the view still usable and is essentially neutral to the program running. Crash-resistant storage implementations are expected to accumulate the desired changes in the batch variable first. If the view is dropped without calling flush, staged changes are simply lost. The returned boolean indicates whether the operation removes the view or not.

fn clear(&mut self)

Clears the view. That can be seen as resetting to default. If the clear is followed by a flush then all the relevant data is removed on the storage.

fn new(context: C) -> Result<Self, ViewError>

Builds a trivial view that is already deleted

impl<C, T> ObjectType for QueueView<C, T>

where C: Send + Sync + Context, T: Serialize + DeserializeOwned + Clone + Send + Sync + OutputType,