Split concerns: collect events as-is for further processing later.

src/Buildalyzer/BuildEventCollector.cs

@@ -0,0 +1,83 @@
+using System.Collections.Concurrent;
+using Microsoft.Build.Framework;
+
+namespace Buildalyzer;
+
+public sealed class BuildEventCollector : IDisposable
+{
+    public BuildEventCollector(IEventSource eventSource)
+    {
+        EventSource = Guard.NotNull(eventSource);
+
+        EventSource.BuildStarted += BuildStarted;
+        EventSource.ProjectStarted += ProjectStarted;
+        EventSource.TaskStarted += TaskStarted;
+        EventSource.TargetStarted += TargetStarted;
+
+        EventSource.CustomEventRaised += CustomEventRaised;
+        EventSource.MessageRaised += MessageRaised;
+        EventSource.ErrorRaised += ErrorRaised;
+        EventSource.StatusEventRaised += StatusEventRaised;
+
+        EventSource.BuildFinished += BuildFinished;
+        EventSource.ProjectFinished += ProjectFinished;
+        EventSource.TaskFinished += TaskFinished;
+        EventSource.TargetFinished += TargetFinished;
+    }
+
+    public ImmutableArray<BuildEventArgs> Events => Bag.ToImmutableArray();
+
+    private readonly IEventSource EventSource;
+
+    private readonly ConcurrentBag<BuildEventArgs> Bag = [];
+
+    private void Add(BuildEventArgs e) => Bag.Add(e);
+
+    private void TaskStarted(object? sender, TaskStartedEventArgs e) => Add(e);
+
+    private void TargetStarted(object? sender, TargetStartedEventArgs e) => Add(e);
+
+    private void TargetFinished(object? sender, TargetFinishedEventArgs e) => Add(e);
+
+    private void ProjectStarted(object? sender, ProjectStartedEventArgs e) => Add(e);
+
+    private void MessageRaised(object? sender, BuildMessageEventArgs e) => Add(e);
+
+    private void StatusEventRaised(object? sender, BuildStatusEventArgs e) => Add(e);
+
+    private void BuildStarted(object? sender, BuildStartedEventArgs e) => Add(e);
+
+    private void ErrorRaised(object? sender, BuildErrorEventArgs e) => Add(e);
+
+    private void CustomEventRaised(object? sender, CustomBuildEventArgs e) => Add(e);
+
+    private void TaskFinished(object? sender, TaskFinishedEventArgs e) => Add(e);
+
+    private void ProjectFinished(object? sender, ProjectFinishedEventArgs e) => Add(e);
+
+    private void BuildFinished(object? sender, BuildFinishedEventArgs e) => Add(e);
+
+    public void Dispose()
+    {
+        if (!Disposed)
+        {
+            EventSource.BuildStarted -= BuildStarted;
+            EventSource.ProjectStarted -= ProjectStarted;
+            EventSource.TaskStarted -= TaskStarted;
+            EventSource.TargetStarted -= TargetStarted;
+
+            EventSource.CustomEventRaised -= CustomEventRaised;
+            EventSource.MessageRaised -= MessageRaised;
+            EventSource.ErrorRaised -= ErrorRaised;
+            EventSource.StatusEventRaised -= StatusEventRaised;
+
+            EventSource.BuildFinished -= BuildFinished;
+            EventSource.ProjectFinished -= ProjectFinished;
+            EventSource.TaskFinished -= TaskFinished;
+            EventSource.TargetFinished -= TargetFinished;
+            Disposed = true;
+        }
+    }
+
+    private bool Disposed;
+}