Trait txn_core::future::AsyncPwm

pub trait AsyncPwm: Sized {
    type Error: Error;
    type Key;
    type Value;
    type Options;
    type Iter<'a>: Iterator<Item = (&'a Self::Key, &'a EntryValue<Self::Value>)>
       where Self: 'a;
    type IntoIter: Iterator<Item = (Self::Key, EntryValue<Self::Value>)>;

    // Required methods
    fn new(
        options: Self::Options
    ) -> impl Future<Output = Result<Self, Self::Error>>;
    fn is_empty(&self) -> impl Future<Output = bool>;
    fn len(&self) -> impl Future<Output = usize>;
    fn validate_entry(
        &self,
        entry: &Entry<Self::Key, Self::Value>
    ) -> impl Future<Output = Result<(), Self::Error>>;
    fn max_batch_size(&self) -> u64;
    fn max_batch_entries(&self) -> u64;
    fn estimate_size(&self, entry: &Entry<Self::Key, Self::Value>) -> u64;
    fn get(
        &self,
        key: &Self::Key
    ) -> impl Future<Output = Result<Option<&EntryValue<Self::Value>>, Self::Error>>;
    fn contains_key(
        &self,
        key: &Self::Key
    ) -> impl Future<Output = Result<bool, Self::Error>>;
    fn insert(
        &mut self,
        key: Self::Key,
        value: EntryValue<Self::Value>
    ) -> impl Future<Output = Result<(), Self::Error>>;
    fn remove_entry(
        &mut self,
        key: &Self::Key
    ) -> impl Future<Output = Result<Option<(Self::Key, EntryValue<Self::Value>)>, Self::Error>>;
    fn rollback(&mut self) -> impl Future<Output = Result<(), Self::Error>>;
    fn iter(
        &self
    ) -> impl Future<Output = impl Iterator<Item = (&Self::Key, &EntryValue<Self::Value>)>>;
    fn into_iter(
        self
    ) -> impl Future<Output = impl Iterator<Item = (Self::Key, EntryValue<Self::Value>)>>;
}

A pending writes manager that can be used to store pending writes in a transaction.

By default, there are two implementations of this trait:

• [IndexMap]: A hash map with consistent ordering and fast lookups.
• [BTreeMap]: A balanced binary tree with ordered keys and fast lookups.

But, users can create their own implementations by implementing this trait. e.g. if you want to implement a recovery transaction manager, you can use a persistent storage to store the pending writes.

Required Associated Types

type Error: Error

The error type returned by the conflict manager.

type Key

The key type.

type Value

The value type.

type Options

The options type used to create the pending manager.

type Iter<'a>: Iterator<Item = (&'a Self::Key, &'a EntryValue<Self::Value>)> where Self: 'a

The iterator type that borrows the pending writes.

type IntoIter: Iterator<Item = (Self::Key, EntryValue<Self::Value>)>

The iterator type that consumes the pending writes.

Required Methods

fn new( options: Self::Options ) -> impl Future<Output = Result<Self, Self::Error>>

Create a new pending manager with the given options.

fn is_empty(&self) -> impl Future<Output = bool>

Returns true if the buffer is empty.

fn len(&self) -> impl Future<Output = usize>

Returns the number of elements in the buffer.

fn validate_entry( &self, entry: &Entry<Self::Key, Self::Value> ) -> impl Future<Output = Result<(), Self::Error>>

Validate if the entry is valid for this database.

e.g.

• If the entry is expired
• If the key or the value is too large
• If the key or the value is empty
• If the key or the value contains invalid characters
• and etc.

fn max_batch_size(&self) -> u64

Returns the maximum batch size in bytes

fn max_batch_entries(&self) -> u64

Returns the maximum entries in batch

fn estimate_size(&self, entry: &Entry<Self::Key, Self::Value>) -> u64

Returns the estimated size of the entry in bytes when persisted in the database.

fn get( &self, key: &Self::Key ) -> impl Future<Output = Result<Option<&EntryValue<Self::Value>>, Self::Error>>

Returns a reference to the value corresponding to the key.

fn contains_key( &self, key: &Self::Key ) -> impl Future<Output = Result<bool, Self::Error>>

Returns true if the pending manager contains the key.

fn insert( &mut self, key: Self::Key, value: EntryValue<Self::Value> ) -> impl Future<Output = Result<(), Self::Error>>

Inserts a key-value pair into the er.

fn remove_entry( &mut self, key: &Self::Key ) -> impl Future<Output = Result<Option<(Self::Key, EntryValue<Self::Value>)>, Self::Error>>

Removes a key from the pending writes, returning the key-value pair if the key was previously in the pending writes.

fn rollback(&mut self) -> impl Future<Output = Result<(), Self::Error>>

Rollback the pending writes.

fn iter( &self ) -> impl Future<Output = impl Iterator<Item = (&Self::Key, &EntryValue<Self::Value>)>>

Returns an iterator over the pending writes.

fn into_iter( self ) -> impl Future<Output = impl Iterator<Item = (Self::Key, EntryValue<Self::Value>)>>

Returns an iterator that consumes the pending writes.

Object Safety

This trait is not object safe.

Implementors

impl<T> AsyncPwm for T

where T: Pwm,

type Error = <T as Pwm>::Error

type Key = <T as Pwm>::Key

type Value = <T as Pwm>::Value

type Options = <T as Pwm>::Options

type Iter<'a> = <T as Pwm>::Iter<'a> where Self: 'a

type IntoIter = <T as Pwm>::IntoIter