ZeroAlloc.Pipeline.Generators 0.1.2

ZeroAlloc.Pipeline

ZeroAlloc.Pipeline is the shared building block for pipeline-aware source generators in the ZeroAlloc ecosystem. It provides the IPipelineBehavior marker interface, PipelineBehaviorAttribute, and the Roslyn-based discovery, validation, and code-emission utilities that generators like ZeroAlloc.Mediator and ZeroAlloc.Validation build on. All pipeline wiring is resolved at compile time — no reflection, no virtual dispatch, no heap allocation per call.

Install

dotnet add package ZeroAlloc.Pipeline
dotnet add package ZeroAlloc.Pipeline.Generators

<PackageReference Include="ZeroAlloc.Pipeline" Version="*" />
<PackageReference Include="ZeroAlloc.Pipeline.Generators" Version="*"
                  OutputItemType="Analyzer"
                  ReferenceOutputAssembly="false" />

Example

using ZeroAlloc.Pipeline;

// 1. Implement IPipelineBehavior and decorate with [PipelineBehavior]
[PipelineBehavior(Order = 1)]
public class LoggingBehavior : IPipelineBehavior
{
    // 2. Expose a public static Handle method matching the host framework's delegate shape
    public static async ValueTask<TResponse> Handle<TRequest, TResponse>(
        TRequest request,
        CancellationToken ct,
        Func<TRequest, CancellationToken, ValueTask<TResponse>> next)
    {
        Console.WriteLine($"Handling {typeof(TRequest).Name}");
        var response = await next(request, ct);
        Console.WriteLine($"Handled {typeof(TRequest).Name}");
        return response;
    }
}

// 3. The host generator (e.g. ZeroAlloc.Mediator) picks this up at compile time
//    and wires it into the generated pipeline — no registration required.

Performance

ZeroAlloc.Pipeline emits static nested lambda chains. Static lambdas carry no closure allocation, and the JIT inlines static call chains aggressively — collapsing N behaviors into straight-line code.

BenchmarkDotNet v0.15.8, .NET 10.0.4, 12th Gen Intel Core i9-12900HK — tests/ZeroAlloc.Pipeline.Benchmarks

Features

• IPipelineBehavior — marker interface; no contract imposed on Handle signature
• PipelineBehaviorAttribute — Order (execution position) and AppliesTo (type scoping)
• Attribute subclassing — framework packages define their own alias; discovery follows the inheritance chain
• Compile-time discovery — PipelineBehaviorDiscoverer and FromAttributeSyntaxContext for incremental generators
• Static emitter — PipelineEmitter.EmitChain generates a nested static lambda chain from a behavior list and a PipelineShape
• PipelineShape — describes type arguments, parameter names, and the innermost body; supports a factory delegate when the body embeds depth-indexed lambda names
• Diagnostic helpers — PipelineDiagnosticRules.FindMissingHandleMethod and FindDuplicateOrders return offending behaviors; the caller maps them to framework-specific diagnostic IDs
• Zero allocation — no reflection, no boxing, no delegate list per call
• netstandard2.0 + Native AOT — works in trimmed, ahead-of-time compiled applications

Documentation

License

MIT