.NET Compaction - Add AsChatReducer() extension to expose CompactionStrategy as IChatReducer (#4664)

* Initial plan * Add ChatStrategyExtensions.cs with AsChatReducer() extension method and tests Co-authored-by: crickman <66376200+crickman@users.noreply.github.com> * Refactor message list creation in ReduceAsync method * Remove unnecessary blank line in AsChatReducer method * Potential fix for pull request finding Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> * Potential fix for pull request finding Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> * Fix test --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: crickman <66376200+crickman@users.noreply.github.com> Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> Co-authored-by: Chris Rickman <crickman@microsoft.com>
2026-06-16 21:04:09 +08:00 · 2026-03-18 17:25:54 +00:00
parent acaf6b7054
commit d3d0100822
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+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.AI;
+using Microsoft.Shared.DiagnosticIds;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Agents.AI.Compaction;
+
+/// <summary>
+/// Provides extension methods for <see cref="CompactionStrategy"/>.
+/// </summary>
+[Experimental(DiagnosticIds.Experiments.AgentsAIExperiments)]
+public static class ChatStrategyExtensions
+{
+    /// <summary>
+    /// Returns an <see cref="IChatReducer"/> that applies this <see cref="CompactionStrategy"/> to reduce a list of messages.
+    /// </summary>
+    /// <param name="strategy">The compaction strategy to wrap as an <see cref="IChatReducer"/>.</param>
+    /// <returns>
+    /// An <see cref="IChatReducer"/> that, on each call to <see cref="IChatReducer.ReduceAsync"/>, builds a
+    /// <see cref="CompactionMessageIndex"/> from the supplied messages and applies the strategy's compaction logic,
+    /// returning the resulting included messages.
+    /// </returns>
+    /// <remarks>
+    /// This allows any <see cref="CompactionStrategy"/> to be used wherever an <see cref="IChatReducer"/> is expected,
+    /// bridging the compaction pipeline into systems bound to the <c>Microsoft.Extensions.AI</c> <see cref="IChatReducer"/> contract.
+    /// </remarks>
+    public static IChatReducer AsChatReducer(this CompactionStrategy strategy)
+    {
+        Throw.IfNull(strategy);
+
+        return new CompactionStrategyChatReducer(strategy);
+    }
+
+    /// <summary>
+    /// An <see cref="IChatReducer"/> adapter that delegates to a <see cref="CompactionStrategy"/>.
+    /// </summary>
+    private sealed class CompactionStrategyChatReducer : IChatReducer
+    {
+        private readonly CompactionStrategy _strategy;
+
+        public CompactionStrategyChatReducer(CompactionStrategy strategy)
+        {
+            this._strategy = strategy;
+        }
+
+        /// <inheritdoc/>
+        public async Task<IEnumerable<ChatMessage>> ReduceAsync(IEnumerable<ChatMessage> messages, CancellationToken cancellationToken = default)
+        {
+            CompactionMessageIndex index = CompactionMessageIndex.Create([.. messages]);
+            await this._strategy.CompactAsync(index, cancellationToken: cancellationToken).ConfigureAwait(false);
+            return index.GetIncludedMessages();
+        }
+    }
+}