Struct linera_views::views::bucket_queue_view::BucketQueueView

pub struct BucketQueueView<C, T, const N: usize> { /* private fields */ }

A view that supports a FIFO queue for values of type T. The size N has to be chosen by taking into account the size of the type T and the basic size of a block. For example a total size of 100 bytes to 10 KB seems adequate.

Implementations

impl<C, T, const N: usize> BucketQueueView<C, T, N>

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

pub fn stored_count(&self) -> usize

Gets the number of entries in the container that are stored

let mut queue = BucketQueueView::<_, u8, 5>::load(context).await.unwrap();
queue.push_back(34);
assert_eq!(queue.stored_count(), 0);

pub fn count(&self) -> usize

The total number of entries of the container

let mut queue = BucketQueueView::<_, u8, 5>::load(context).await.unwrap();
queue.push_back(34);
assert_eq!(queue.count(), 1);

impl<C, T, const N: usize> BucketQueueView<C, T, N>

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

pub fn front(&self) -> Option<&T>

Gets a reference on the front value if any.

let mut queue = BucketQueueView::<_, u8, 5>::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(42);
assert_eq!(queue.front().cloned(), Some(34));

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

Reads the front value, if any.

let mut queue = BucketQueueView::<_, u8, 5>::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(42);
let front = queue.front_mut().unwrap();
*front = 43;
assert_eq!(queue.front().cloned(), Some(43));

pub async fn delete_front(&mut self) -> Result<(), ViewError>

Deletes the front value, if any.

let mut queue = BucketQueueView::<_, u128, 5>::load(context).await.unwrap();
queue.push_back(34 as u128);
queue.delete_front().await.unwrap();
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 = BucketQueueView::<_, u128, 5>::load(context).await.unwrap();
queue.push_back(34);
assert_eq!(queue.elements().await.unwrap(), vec![34]);

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

Returns the list of elements in the queue.

let mut queue = BucketQueueView::<_, u128, 5>::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(37);
assert_eq!(queue.elements().await.unwrap(), vec![34, 37]);

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

Returns the last element of a bucket queue view

let mut queue = BucketQueueView::<_, u128, 5>::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(37);
assert_eq!(queue.back().await.unwrap(), Some(37));

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

Returns the first elements of a bucket queue view

let mut queue = BucketQueueView::<_, u128, 5>::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(37);
queue.push_back(47);
assert_eq!(queue.read_front(2).await.unwrap(), vec![34, 37]);

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

Returns the last element of a bucket queue view

let mut queue = BucketQueueView::<_, u128, 5>::load(context).await.unwrap();
queue.push_back(34);
queue.push_back(37);
queue.push_back(47);
assert_eq!(queue.read_back(2).await.unwrap(), vec![37, 47]);

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

Gets a mutable iterator on the entries of the queue

let mut queue = BucketQueueView::<_, u8, 5>::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, const N: usize> ClonableView<C> for BucketQueueView<C, T, N>

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

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, const N: usize> ContainerType for BucketQueueView<C, T, N>

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, T, const N: usize> HashableView<C> for BucketQueueView<C, T, N>

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, const N: usize> OutputType for BucketQueueView<C, T, N>

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, const N: usize> TypeName for BucketQueueView<C, T, N>

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

Returns a GraphQL type name.

impl<C, T, const N: usize> View<C> for BucketQueueView<C, T, N>

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

const NUM_INIT_KEYS: usize = 2usize

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, const N: usize> ObjectType for BucketQueueView<C, T, N>

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