Add support for Protobuf_ProtoRoot

src/csharp/Grpc.Tools.Tests/CSharpGeneratorTest.cs

@@ -89,8 +89,8 @@ namespace Grpc.Tools.Tests
         public void OutputDirPatched()
         {
             var item = Utils.MakeItem("sub/foo.proto", "OutputDir", "out");
-            _generator.PatchOutputDirectory(item);
-            var poss = _generator.GetPossibleOutputs(item);
+            var output = _generator.PatchOutputDirectory(item);
+            var poss = _generator.GetPossibleOutputs(output);
             Assert.AreEqual(1, poss.Length);
             Assert.That(poss[0], Is.EqualTo("out/sub/Foo.cs") | Is.EqualTo("out\\sub\\Foo.cs"));
         }

src/csharp/Grpc.Tools/GeneratorServices.cs

@@ -57,9 +57,10 @@ namespace Grpc.Tools
         // Update OutputDir and GrpcOutputDir for the item and all subsequent
         // targets using this item. This should only be done if the real
         // output directories for protoc should be modified.
-        public virtual void PatchOutputDirectory(ITaskItem protoItem)
+        public virtual ITaskItem PatchOutputDirectory(ITaskItem protoItem)
         {
             // Nothing to do
+            return protoItem;
         }
 
         public abstract string[] GetPossibleOutputs(ITaskItem protoItem);
@@ -116,23 +117,25 @@ namespace Grpc.Tools
     {
         public CSharpGeneratorServices(TaskLoggingHelper log) : base(log) { }
 
-        public override void PatchOutputDirectory(ITaskItem protoItem)
+        public override ITaskItem PatchOutputDirectory(ITaskItem protoItem)
         {
-            string root = protoItem.GetMetadata(Metadata.ProtoRoot);
-            string proto = protoItem.ItemSpec;
+            var outputItem = new TaskItem(protoItem);
+            string root = outputItem.GetMetadata(Metadata.ProtoRoot);
+            string proto = outputItem.ItemSpec;
             string relative = GetRelativeDir(root, proto, Log);
 
-            string outdir = protoItem.GetMetadata(Metadata.OutputDir);
+            string outdir = outputItem.GetMetadata(Metadata.OutputDir);
             string pathStem = Path.Combine(outdir, relative);
-            protoItem.SetMetadata(Metadata.OutputDir, pathStem);
+            outputItem.SetMetadata(Metadata.OutputDir, pathStem);
 
             // Override outdir if GrpcOutputDir present, default to proto output.
-            string grpcdir = protoItem.GetMetadata(Metadata.GrpcOutputDir);
+            string grpcdir = outputItem.GetMetadata(Metadata.GrpcOutputDir);
             if (grpcdir != "")
             {
                 pathStem = Path.Combine(grpcdir, relative);
             }
-            protoItem.SetMetadata(Metadata.GrpcOutputDir, pathStem);
+            outputItem.SetMetadata(Metadata.GrpcOutputDir, pathStem);
+            return outputItem;
         }
 
         public override string[] GetPossibleOutputs(ITaskItem protoItem)

src/csharp/Grpc.Tools/ProtoCompilerOutputs.cs

@@ -79,15 +79,14 @@ namespace Grpc.Tools
             var patched = new List<ITaskItem>();
             foreach (var proto in Protobuf)
             {
-                // This operates on a local copy and has no effect on the MSBuild instance!
-                generator.PatchOutputDirectory(proto);
-                patched.Add(proto);
+                var patchedProto = generator.PatchOutputDirectory(proto);
+                patched.Add(patchedProto);
 
-                var outputs = generator.GetPossibleOutputs(proto);
+                var outputs = generator.GetPossibleOutputs(patchedProto);
                 foreach (string output in outputs)
                 {
                     var ti = new TaskItem(output);
-                    ti.SetMetadata(Metadata.Source, proto.ItemSpec);
+                    ti.SetMetadata(Metadata.Source, patchedProto.ItemSpec);
                     possible.Add(ti);
                 }
             }

src/csharp/Grpc.Tools/build/_protobuf/Google.Protobuf.Tools.targets

@@ -135,6 +135,7 @@
       <!-- Out-of-project files will have respective ProtoRoot='%(RelativeDir)'. -->
       <Protobuf_Rooted Include="@(_Protobuf_NoRootElsewhere)">
         <ProtoRoot>%(RelativeDir)</ProtoRoot>
+		<ProtoRoot Condition=" '$(Protobuf_ProtoRoot)' != '' ">$(Protobuf_ProtoRoot)</ProtoRoot>
       </Protobuf_Rooted>
     </ItemGroup>
   </Target>