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BlubbFish
2019-12-04 18:57:18 +01:00
parent 4692422c9a
commit 6263791dff
225 changed files with 33065 additions and 2 deletions
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Swan/Messaging/IMessageHubMessage.cs
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namespace Swan.Messaging
{
/// <summary>
/// A Message to be published/delivered by Messenger.
/// </summary>
public interface IMessageHubMessage
{
/// <summary>
/// The sender of the message, or null if not supported by the message implementation.
/// </summary>
object Sender { get; }
}
}
Swan/Messaging/IMessageHubSubscription.cs
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namespace Swan.Messaging
{
/// <summary>
/// Represents a message subscription.
/// </summary>
public interface IMessageHubSubscription
{
/// <summary>
/// Token returned to the subscribed to reference this subscription.
/// </summary>
MessageHubSubscriptionToken SubscriptionToken { get; }
/// <summary>
/// Whether delivery should be attempted.
/// </summary>
/// <param name="message">Message that may potentially be delivered.</param>
/// <returns><c>true</c> - ok to send, <c>false</c> - should not attempt to send.</returns>
bool ShouldAttemptDelivery(IMessageHubMessage message);
/// <summary>
/// Deliver the message.
/// </summary>
/// <param name="message">Message to deliver.</param>
void Deliver(IMessageHubMessage message);
}
}
Swan/Messaging/MessageHub.cs
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// ===============================================================================
// TinyIoC - TinyMessenger
//
// A simple messenger/event aggregator.
//
// https://github.com/grumpydev/TinyIoC/blob/master/src/TinyIoC/TinyMessenger.cs
// ===============================================================================
// Copyright © Steven Robbins. All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
// ===============================================================================
namespace Swan.Messaging
{
using System.Threading.Tasks;
using System;
using System.Collections.Generic;
using System.Linq;
#region Message Types / Interfaces
/// <summary>
/// Message proxy definition.
///
/// A message proxy can be used to intercept/alter messages and/or
/// marshal delivery actions onto a particular thread.
/// </summary>
public interface IMessageHubProxy
{
/// <summary>
/// Delivers the specified message.
/// </summary>
/// <param name="message">The message.</param>
/// <param name="subscription">The subscription.</param>
void Deliver(IMessageHubMessage message, IMessageHubSubscription subscription);
}
/// <summary>
/// Default "pass through" proxy.
///
/// Does nothing other than deliver the message.
/// </summary>
public sealed class MessageHubDefaultProxy : IMessageHubProxy
{
private MessageHubDefaultProxy()
{
// placeholder
}
/// <summary>
/// Singleton instance of the proxy.
/// </summary>
public static MessageHubDefaultProxy Instance { get; } = new MessageHubDefaultProxy();
/// <summary>
/// Delivers the specified message.
/// </summary>
/// <param name="message">The message.</param>
/// <param name="subscription">The subscription.</param>
public void Deliver(IMessageHubMessage message, IMessageHubSubscription subscription)
=> subscription.Deliver(message);
}
#endregion
#region Hub Interface
/// <summary>
/// Messenger hub responsible for taking subscriptions/publications and delivering of messages.
/// </summary>
public interface IMessageHub
{
/// <summary>
/// Subscribe to a message type with the given destination and delivery action.
/// Messages will be delivered via the specified proxy.
///
/// All messages of this type will be delivered.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="deliveryAction">Action to invoke when message is delivered.</param>
/// <param name="useStrongReferences">Use strong references to destination and deliveryAction.</param>
/// <param name="proxy">Proxy to use when delivering the messages.</param>
/// <returns>MessageSubscription used to unsubscribing.</returns>
MessageHubSubscriptionToken Subscribe<TMessage>(
Action<TMessage> deliveryAction,
bool useStrongReferences,
IMessageHubProxy proxy)
where TMessage : class, IMessageHubMessage;
/// <summary>
/// Subscribe to a message type with the given destination and delivery action with the given filter.
/// Messages will be delivered via the specified proxy.
/// All references are held with WeakReferences
/// Only messages that "pass" the filter will be delivered.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="deliveryAction">Action to invoke when message is delivered.</param>
/// <param name="messageFilter">The message filter.</param>
/// <param name="useStrongReferences">Use strong references to destination and deliveryAction.</param>
/// <param name="proxy">Proxy to use when delivering the messages.</param>
/// <returns>
/// MessageSubscription used to unsubscribing.
/// </returns>
MessageHubSubscriptionToken Subscribe<TMessage>(
Action<TMessage> deliveryAction,
Func<TMessage, bool> messageFilter,
bool useStrongReferences,
IMessageHubProxy proxy)
where TMessage : class, IMessageHubMessage;
/// <summary>
/// Unsubscribe from a particular message type.
///
/// Does not throw an exception if the subscription is not found.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="subscriptionToken">Subscription token received from Subscribe.</param>
void Unsubscribe<TMessage>(MessageHubSubscriptionToken subscriptionToken)
where TMessage : class, IMessageHubMessage;
/// <summary>
/// Publish a message to any subscribers.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="message">Message to deliver.</param>
void Publish<TMessage>(TMessage message)
where TMessage : class, IMessageHubMessage;
/// <summary>
/// Publish a message to any subscribers asynchronously.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="message">Message to deliver.</param>
/// <returns>A task from Publish action.</returns>
Task PublishAsync<TMessage>(TMessage message)
where TMessage : class, IMessageHubMessage;
}
#endregion
#region Hub Implementation
/// <inheritdoc />
/// <example>
/// The following code describes how to use a MessageHub. Both the
/// subscription and the message sending are done in the same place but this is only for explanatory purposes.
/// <code>
/// class Example
/// {
/// using Swan;
/// using Swan.Components;
///
/// static void Main()
/// {
/// // using DependencyContainer to create an instance of MessageHub
/// var messageHub = DependencyContainer
/// .Current
/// .Resolve&lt;IMessageHub&gt;() as MessageHub;
///
/// // create an instance of the publisher class
/// // which has a string as its content
/// var message = new MessageHubGenericMessage&lt;string&gt;(new object(), "SWAN");
///
/// // subscribe to the publisher's event
/// // and just print out the content which is a string
/// // a token is returned which can be used to unsubscribe later on
/// var token = messageHub
/// .Subscribe&lt;MessageHubGenericMessage&lt;string&gt;&gt;(m =&gt; m.Content.Info());
///
/// // publish the message described above which is
/// // the string 'SWAN'
/// messageHub.Publish(message);
///
/// // unsuscribe, we will no longer receive any messages
/// messageHub.Unsubscribe&lt;MessageHubGenericMessage&lt;string&gt;&gt;(token);
///
/// Terminal.Flush();
/// }
///
/// }
/// </code>
/// </example>
public sealed class MessageHub : IMessageHub
{
#region Private Types and Interfaces
private readonly object _subscriptionsPadlock = new object();
private readonly Dictionary<Type, List<SubscriptionItem>> _subscriptions =
new Dictionary<Type, List<SubscriptionItem>>();
private class WeakMessageSubscription<TMessage> : IMessageHubSubscription
where TMessage : class, IMessageHubMessage
{
private readonly WeakReference _deliveryAction;
private readonly WeakReference _messageFilter;
/// <summary>
/// Initializes a new instance of the <see cref="WeakMessageSubscription{TMessage}" /> class.
/// </summary>
/// <param name="subscriptionToken">The subscription token.</param>
/// <param name="deliveryAction">The delivery action.</param>
/// <param name="messageFilter">The message filter.</param>
/// <exception cref="ArgumentNullException">subscriptionToken
/// or
/// deliveryAction
/// or
/// messageFilter.</exception>
public WeakMessageSubscription(
MessageHubSubscriptionToken subscriptionToken,
Action<TMessage> deliveryAction,
Func<TMessage, bool> messageFilter)
{
SubscriptionToken = subscriptionToken ?? throw new ArgumentNullException(nameof(subscriptionToken));
_deliveryAction = new WeakReference(deliveryAction);
_messageFilter = new WeakReference(messageFilter);
}
public MessageHubSubscriptionToken SubscriptionToken { get; }
public bool ShouldAttemptDelivery(IMessageHubMessage message)
{
return _deliveryAction.IsAlive && _messageFilter.IsAlive &&
((Func<TMessage, bool>) _messageFilter.Target).Invoke((TMessage) message);
}
public void Deliver(IMessageHubMessage message)
{
if (_deliveryAction.IsAlive)
{
((Action<TMessage>) _deliveryAction.Target).Invoke((TMessage) message);
}
}
}
private class StrongMessageSubscription<TMessage> : IMessageHubSubscription
where TMessage : class, IMessageHubMessage
{
private readonly Action<TMessage> _deliveryAction;
private readonly Func<TMessage, bool> _messageFilter;
/// <summary>
/// Initializes a new instance of the <see cref="StrongMessageSubscription{TMessage}" /> class.
/// </summary>
/// <param name="subscriptionToken">The subscription token.</param>
/// <param name="deliveryAction">The delivery action.</param>
/// <param name="messageFilter">The message filter.</param>
/// <exception cref="ArgumentNullException">subscriptionToken
/// or
/// deliveryAction
/// or
/// messageFilter.</exception>
public StrongMessageSubscription(
MessageHubSubscriptionToken subscriptionToken,
Action<TMessage> deliveryAction,
Func<TMessage, bool> messageFilter)
{
SubscriptionToken = subscriptionToken ?? throw new ArgumentNullException(nameof(subscriptionToken));
_deliveryAction = deliveryAction;
_messageFilter = messageFilter;
}
public MessageHubSubscriptionToken SubscriptionToken { get; }
public bool ShouldAttemptDelivery(IMessageHubMessage message) => _messageFilter.Invoke((TMessage) message);
public void Deliver(IMessageHubMessage message) => _deliveryAction.Invoke((TMessage) message);
}
#endregion
#region Subscription dictionary
private class SubscriptionItem
{
public SubscriptionItem(IMessageHubProxy proxy, IMessageHubSubscription subscription)
{
Proxy = proxy;
Subscription = subscription;
}
public IMessageHubProxy Proxy { get; }
public IMessageHubSubscription Subscription { get; }
}
#endregion
#region Public API
/// <summary>
/// Subscribe to a message type with the given destination and delivery action.
/// Messages will be delivered via the specified proxy.
///
/// All messages of this type will be delivered.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="deliveryAction">Action to invoke when message is delivered.</param>
/// <param name="useStrongReferences">Use strong references to destination and deliveryAction. </param>
/// <param name="proxy">Proxy to use when delivering the messages.</param>
/// <returns>MessageSubscription used to unsubscribing.</returns>
public MessageHubSubscriptionToken Subscribe<TMessage>(
Action<TMessage> deliveryAction,
bool useStrongReferences = true,
IMessageHubProxy? proxy = null)
where TMessage : class, IMessageHubMessage
{
return Subscribe(deliveryAction, m => true, useStrongReferences, proxy);
}
/// <summary>
/// Subscribe to a message type with the given destination and delivery action with the given filter.
/// Messages will be delivered via the specified proxy.
/// All references are held with WeakReferences
/// Only messages that "pass" the filter will be delivered.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="deliveryAction">Action to invoke when message is delivered.</param>
/// <param name="messageFilter">The message filter.</param>
/// <param name="useStrongReferences">Use strong references to destination and deliveryAction.</param>
/// <param name="proxy">Proxy to use when delivering the messages.</param>
/// <returns>
/// MessageSubscription used to unsubscribing.
/// </returns>
public MessageHubSubscriptionToken Subscribe<TMessage>(
Action<TMessage> deliveryAction,
Func<TMessage, bool> messageFilter,
bool useStrongReferences = true,
IMessageHubProxy? proxy = null)
where TMessage : class, IMessageHubMessage
{
if (deliveryAction == null)
throw new ArgumentNullException(nameof(deliveryAction));
if (messageFilter == null)
throw new ArgumentNullException(nameof(messageFilter));
lock (_subscriptionsPadlock)
{
if (!_subscriptions.TryGetValue(typeof(TMessage), out var currentSubscriptions))
{
currentSubscriptions = new List<SubscriptionItem>();
_subscriptions[typeof(TMessage)] = currentSubscriptions;
}
var subscriptionToken = new MessageHubSubscriptionToken(this, typeof(TMessage));
IMessageHubSubscription subscription;
if (useStrongReferences)
{
subscription = new StrongMessageSubscription<TMessage>(
subscriptionToken,
deliveryAction,
messageFilter);
}
else
{
subscription = new WeakMessageSubscription<TMessage>(
subscriptionToken,
deliveryAction,
messageFilter);
}
currentSubscriptions.Add(new SubscriptionItem(proxy ?? MessageHubDefaultProxy.Instance, subscription));
return subscriptionToken;
}
}
/// <inheritdoc />
public void Unsubscribe<TMessage>(MessageHubSubscriptionToken subscriptionToken)
where TMessage : class, IMessageHubMessage
{
if (subscriptionToken == null)
throw new ArgumentNullException(nameof(subscriptionToken));
lock (_subscriptionsPadlock)
{
if (!_subscriptions.TryGetValue(typeof(TMessage), out var currentSubscriptions))
return;
var currentlySubscribed = currentSubscriptions
.Where(sub => ReferenceEquals(sub.Subscription.SubscriptionToken, subscriptionToken))
.ToList();
currentlySubscribed.ForEach(sub => currentSubscriptions.Remove(sub));
}
}
/// <summary>
/// Publish a message to any subscribers.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="message">Message to deliver.</param>
public void Publish<TMessage>(TMessage message)
where TMessage : class, IMessageHubMessage
{
if (message == null)
throw new ArgumentNullException(nameof(message));
List<SubscriptionItem> currentlySubscribed;
lock (_subscriptionsPadlock)
{
if (!_subscriptions.TryGetValue(typeof(TMessage), out var currentSubscriptions))
return;
currentlySubscribed = currentSubscriptions
.Where(sub => sub.Subscription.ShouldAttemptDelivery(message))
.ToList();
}
currentlySubscribed.ForEach(sub =>
{
try
{
sub.Proxy.Deliver(message, sub.Subscription);
}
catch
{
// Ignore any errors and carry on
}
});
}
/// <summary>
/// Publish a message to any subscribers asynchronously.
/// </summary>
/// <typeparam name="TMessage">Type of message.</typeparam>
/// <param name="message">Message to deliver.</param>
/// <returns>A task with the publish.</returns>
public Task PublishAsync<TMessage>(TMessage message)
where TMessage : class, IMessageHubMessage
{
return Task.Run(() => Publish(message));
}
#endregion
}
#endregion
}
Swan/Messaging/MessageHubMessageBase.cs
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namespace Swan.Messaging
{
using System;
/// <summary>
/// Base class for messages that provides weak reference storage of the sender.
/// </summary>
public abstract class MessageHubMessageBase
: IMessageHubMessage
{
/// <summary>
/// Store a WeakReference to the sender just in case anyone is daft enough to
/// keep the message around and prevent the sender from being collected.
/// </summary>
private readonly WeakReference _sender;
/// <summary>
/// Initializes a new instance of the <see cref="MessageHubMessageBase"/> class.
/// </summary>
/// <param name="sender">The sender.</param>
/// <exception cref="System.ArgumentNullException">sender.</exception>
protected MessageHubMessageBase(object sender)
{
if (sender == null)
throw new ArgumentNullException(nameof(sender));
_sender = new WeakReference(sender);
}
/// <inheritdoc />
public object Sender => _sender.Target;
}
/// <summary>
/// Generic message with user specified content.
/// </summary>
/// <typeparam name="TContent">Content type to store.</typeparam>
public class MessageHubGenericMessage<TContent>
: MessageHubMessageBase
{
/// <summary>
/// Initializes a new instance of the <see cref="MessageHubGenericMessage{TContent}"/> class.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="content">The content.</param>
public MessageHubGenericMessage(object sender, TContent content)
: base(sender)
{
Content = content;
}
/// <summary>
/// Contents of the message.
/// </summary>
public TContent Content { get; protected set; }
}
}
Swan/Messaging/MessageHubSubscriptionToken.cs
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namespace Swan.Messaging
{
using System;
/// <summary>
/// Represents an active subscription to a message.
/// </summary>
public sealed class MessageHubSubscriptionToken
: IDisposable
{
private readonly WeakReference _hub;
private readonly Type _messageType;
/// <summary>
/// Initializes a new instance of the <see cref="MessageHubSubscriptionToken"/> class.
/// </summary>
/// <param name="hub">The hub.</param>
/// <param name="messageType">Type of the message.</param>
/// <exception cref="System.ArgumentNullException">hub.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">messageType.</exception>
public MessageHubSubscriptionToken(IMessageHub hub, Type messageType)
{
if (hub == null)
{
throw new ArgumentNullException(nameof(hub));
}
if (!typeof(IMessageHubMessage).IsAssignableFrom(messageType))
{
throw new ArgumentOutOfRangeException(nameof(messageType));
}
_hub = new WeakReference(hub);
_messageType = messageType;
}
/// <inheritdoc />
public void Dispose()
{
if (_hub.IsAlive && _hub.Target is IMessageHub hub)
{
var unsubscribeMethod = typeof(IMessageHub).GetMethod(nameof(IMessageHub.Unsubscribe),
new[] {typeof(MessageHubSubscriptionToken)});
unsubscribeMethod = unsubscribeMethod.MakeGenericMethod(_messageType);
unsubscribeMethod.Invoke(hub, new object[] {this});
}
GC.SuppressFinalize(this);
}
}
}