ArlecchinoAsyncStore class

Namespace: Arlecchino.Atoms · Assembly: Arlecchino

A store that has to fetch something before it holds the truth. Override ArlecchinoAsyncStore.LoadAsync, and the load is started as the application starts and its bookkeeping kept.

public sealed class SettingsStore : ArlecchinoAsyncStore
{
public TrackedAtom<string> Server { get; } = new("127.0.0.1");

protected override async Task LoadAsync(CancellationToken token)
{
await using var fs = new FileStream(SettingsPath, FileMode.Open, FileAccess.Read);
var saved = await JsonSerializer.DeserializeAsync<Saved>(fs, cancellationToken: token);

Server.Post(saved.Server);
}
}

public abstract class ArlecchinoAsyncStore : IArlecchinoStore

Implements IArlecchinoStore

Constructors

Member	Summary
ArlecchinoAsyncStore()	Creates the store.

Properties

Member	Summary
Error	What the load threw, or null while it has not failed.
Failed	Whether the load threw. What it threw is in ArlecchinoAsyncStore.Error.
IsLoaded	Whether the load finished and the atoms hold what it fetched.
IsLoading	Whether the load is still running.
Ready	Completes when the store is loaded, faults with whatever ArlecchinoAsyncStore.LoadAsync threw, and cancels when the application stopped first. A view reads ArlecchinoAsyncStore.Status instead of awaiting it.
Status	How the load is going, as an atom, so a view that reads it redraws when it changes.

Methods

Member	Summary
LoadAsync(CancellationToken)	Fetches what the store needs, off the drawing thread, so what it loads reaches the atoms through Post. Throwing is a normal outcome and turns the status to failed.

Constructors in detail

ArlecchinoAsyncStore()

public ArlecchinoAsyncStore();

Creates the store.

Properties in detail

Error

public IReadableAtom<Exception?> Error { get; }

What the load threw, or null while it has not failed.

Type IReadableAtom<Exception>

Failed

public bool Failed { get; }

Whether the load threw. What it threw is in ArlecchinoAsyncStore.Error.

Type bool

IsLoaded

public bool IsLoaded { get; }

Whether the load finished and the atoms hold what it fetched.

Type bool

IsLoading

public bool IsLoading { get; }

Whether the load is still running.

Type bool

Ready

public Task Ready { get; }

Completes when the store is loaded, faults with whatever ArlecchinoAsyncStore.LoadAsync threw, and cancels when the application stopped first. A view reads ArlecchinoAsyncStore.Status instead of awaiting it.

Type Task

Status

public IReadableAtom<LoadStatus> Status { get; }

How the load is going, as an atom, so a view that reads it redraws when it changes.

Type IReadableAtom<LoadStatus>

Methods in detail

LoadAsync(CancellationToken)

public abstract Task LoadAsync(CancellationToken token);

Fetches what the store needs, off the drawing thread, so what it loads reaches the atoms through Post. Throwing is a normal outcome and turns the status to failed.

Parameters

Name	Type	Description
token	CancellationToken	Canceled when the application is shutting down.

Returns Task — A task that completes when the store is ready.