Implement a simple base for document classifiers

This should allow us to de-dupe a lot of code in MVC.

src/Microsoft.AspNetCore.Razor.Evolution/DefaultDocumentClassifierPass.cs

@@ -0,0 +1,19 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Evolution
+{
+    internal class DefaultDocumentClassifierPass : DocumentClassifierPassBase
+    {
+        public override int Order => RazorIRPass.DefaultDocumentClassifierOrder;
+
+        protected override string DocumentKind => "default";
+
+        protected override bool IsMatch(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
+        {
+            return true;
+        }
+    }
+}

src/Microsoft.AspNetCore.Razor.Evolution/DocumentClassifierPassBase.cs

@@ -6,22 +6,35 @@ using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
 
 namespace Microsoft.AspNetCore.Razor.Evolution
 {
-    internal class DefaultDocumentClassifier : RazorIRPassBase
+    public abstract class DocumentClassifierPassBase : RazorIRPassBase
     {
-        public override int Order => RazorIRPass.DefaultDocumentClassifierOrder;
+        protected abstract string DocumentKind { get; }
 
-        public static string DocumentKind = "default";
+        public override int Order => RazorIRPass.DocumentClassifierOrder;
 
-        public override DocumentIRNode ExecuteCore(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
+        public sealed override DocumentIRNode ExecuteCore(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
         {
             if (irDocument.DocumentKind != null)
             {
                 return irDocument;
             }
 
+            if (!IsMatch(codeDocument, irDocument))
+            {
+                return irDocument;
+            }
+
             irDocument.DocumentKind = DocumentKind;
 
-            // Rewrite a use default namespace and class declaration.
+            Rewrite(codeDocument, irDocument);
+
+            return irDocument;
+        }
+
+        private void Rewrite(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
+        {
+            // Rewrite the document from a flat structure to use a sensible default structure,
+            // a namespace and class declaration with a single 'razor' method.
             var children = new List<RazorIRNode>(irDocument.Children);
             irDocument.Children.Clear();
 
@@ -39,7 +52,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             var method = new RazorMethodDeclarationIRNode()
             {
                 //AccessModifier = "public",
-               // Modifiers = new List<string>() { "async" },
+                // Modifiers = new List<string>() { "async" },
                 //Name = "Execute",
                 //ReturnType = "Task",
             };
@@ -62,7 +75,20 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 visitor.Visit(children[i]);
             }
 
-            return irDocument;
+            // Note that this is called at the *end* of rewriting so that user code can see the tree
+            // and look at its content to make a decision.
+            OnDocumentStructureCreated(codeDocument, @namespace, @class, method);
+        }
+
+        protected abstract bool IsMatch(RazorCodeDocument codeDocument, DocumentIRNode irDocument);
+
+        protected virtual void OnDocumentStructureCreated(
+            RazorCodeDocument codeDocument,
+            NamespaceDeclarationIRNode @namespace,
+            ClassDeclarationIRNode @class,
+            RazorMethodDeclarationIRNode @method)
+        {
+            // Intentionally empty.
         }
 
         private class Visitor : RazorIRNodeVisitor

src/Microsoft.AspNetCore.Razor.Evolution/RazorEngine.cs

@@ -59,7 +59,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             builder.Features.Add(new TagHelperBinderSyntaxTreePass());
 
             // IR Passes
-            builder.Features.Add(new DefaultDocumentClassifier());
+            builder.Features.Add(new DefaultDocumentClassifierPass());
             builder.Features.Add(new DefaultDirectiveIRPass());
         }
 

test/Microsoft.AspNetCore.Razor.Evolution.Test/DefaultDirectiveIRPassTest.cs

@@ -226,7 +226,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             Assert.NotNull(irDocument);
 
             // These tests depend on the document->namespace->class structure.
-            irDocument = new DefaultDocumentClassifier() { Engine = engine, }.Execute(codeDocument, irDocument);
+            irDocument = new DefaultDocumentClassifierPass() { Engine = engine, }.Execute(codeDocument, irDocument);
             return irDocument;
         }
     }

test/Microsoft.AspNetCore.Razor.Evolution.Test/DefaultDocumentClassifierPassTest.cs

@@ -0,0 +1,56 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+
+using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
+using Xunit;
+using static Microsoft.AspNetCore.Razor.Evolution.Intermediate.RazorIRAssert;
+
+namespace Microsoft.AspNetCore.Razor.Evolution
+{
+    // We're purposely lean on tests here because the functionality is well covered by
+    // integration tests, and is mostly implemented by the base class.
+    public class DefaultDocumentClassifierPassTest
+    {
+        [Fact]
+        public void Execute_IgnoresDocumentsWithDocumentKind()
+        {
+            // Arrange
+            var irDocument = new DocumentIRNode()
+            {
+                DocumentKind = "ignore",
+            };
+
+            var pass = new DefaultDocumentClassifierPass();
+            pass.Engine = RazorEngine.CreateEmpty(b => { });
+
+            // Act
+            pass.Execute(TestRazorCodeDocument.CreateEmpty(), irDocument);
+
+            // Assert
+            Assert.Equal("ignore", irDocument.DocumentKind);
+            NoChildren(irDocument);
+        }
+
+        [Fact]
+        public void Execute_CreatesClassStructure()
+        {
+            // Arrange
+            var irDocument = new DocumentIRNode();
+
+            var pass = new DefaultDocumentClassifierPass();
+            pass.Engine = RazorEngine.CreateEmpty(b =>{ });
+
+            // Act
+            pass.Execute(TestRazorCodeDocument.CreateEmpty(), irDocument);
+
+            // Assert
+            Assert.Equal("default", irDocument.DocumentKind);
+
+            var @namespace = SingleChild<NamespaceDeclarationIRNode>(irDocument);
+            var @class = SingleChild<ClassDeclarationIRNode>(@namespace);
+            var method = SingleChild<RazorMethodDeclarationIRNode>(@class);
+            NoChildren(method);
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Evolution.Test/DocumentClassifierPassBaseTest.cs

@@ -2,16 +2,17 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 
+using System;
 using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
 using Xunit;
 using static Microsoft.AspNetCore.Razor.Evolution.Intermediate.RazorIRAssert;
 
 namespace Microsoft.AspNetCore.Razor.Evolution
 {
-    public class DefaultDocumentClassifierTest
+    public class DocumentClassifierPassBaseTest
     {
         [Fact]
-        public void Execute_IgnoresDocumentsWithDocumentKind()
+        public void Execute_HasDocumentKind_IgnoresDocument()
         {
             // Arrange
             var irDocument = new DocumentIRNode()
@@ -19,7 +20,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 DocumentKind = "ignore",
             };
 
-            var pass = new DefaultDocumentClassifier();
+            var pass = new TestDocumentClassifierPass();
             pass.Engine = RazorEngine.CreateEmpty(b => { });
 
             // Act
@@ -31,19 +32,39 @@ namespace Microsoft.AspNetCore.Razor.Evolution
         }
 
         [Fact]
-        public void Execute_CreatesClassStructure()
+        public void Execute_NoMatch_IgnoresDocument()
         {
             // Arrange
             var irDocument = new DocumentIRNode();
 
-            var pass = new DefaultDocumentClassifier();
+            var pass = new TestDocumentClassifierPass()
-            pass.Engine = RazorEngine.CreateEmpty(b =>{ });
+            {
+                Engine = RazorEngine.CreateEmpty(b => { }),
+                ShouldMatch = false,
+            };
 
             // Act
             pass.Execute(TestRazorCodeDocument.CreateEmpty(), irDocument);
 
             // Assert
-            Assert.Equal(DefaultDocumentClassifier.DocumentKind, irDocument.DocumentKind);
+            Assert.Null(irDocument.DocumentKind);
+            NoChildren(irDocument);
+        }
+
+        [Fact]
+        public void Execute_Match_SetsDocumentType_AndCreatesStructure()
+        {
+            // Arrange
+            var irDocument = new DocumentIRNode();
+
+            var pass = new TestDocumentClassifierPass();
+            pass.Engine = RazorEngine.CreateEmpty(b => { });
+
+            // Act
+            pass.Execute(TestRazorCodeDocument.CreateEmpty(), irDocument);
+
+            // Assert
+            Assert.Equal("test", irDocument.DocumentKind);
 
             var @namespace = SingleChild<NamespaceDeclarationIRNode>(irDocument);
             var @class = SingleChild<ClassDeclarationIRNode>(@namespace);
@@ -60,7 +81,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             var builder = RazorIRBuilder.Create(irDocument);
             builder.Add(new ChecksumIRNode());
 
-            var pass = new DefaultDocumentClassifier();
+            var pass = new TestDocumentClassifierPass();
             pass.Engine = RazorEngine.CreateEmpty(b => { });
 
             // Act
@@ -82,7 +103,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             var builder = RazorIRBuilder.Create(irDocument);
             builder.Add(new UsingStatementIRNode());
 
-            var pass = new DefaultDocumentClassifier();
+            var pass = new TestDocumentClassifierPass();
             pass.Engine = RazorEngine.CreateEmpty(b => { });
 
             // Act
@@ -105,7 +126,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             var builder = RazorIRBuilder.Create(irDocument);
             builder.Add(new DeclareTagHelperFieldsIRNode());
 
-            var pass = new DefaultDocumentClassifier();
+            var pass = new TestDocumentClassifierPass();
             pass.Engine = RazorEngine.CreateEmpty(b => { });
 
             // Act
@@ -130,7 +151,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
             builder.Add(new HtmlContentIRNode());
             builder.Add(new CSharpStatementIRNode());
 
-            var pass = new DefaultDocumentClassifier();
+            var pass = new TestDocumentClassifierPass();
             pass.Engine = RazorEngine.CreateEmpty(b => { });
 
             // Act
@@ -145,5 +166,66 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 n => Assert.IsType<HtmlContentIRNode>(n),
                 n => Assert.IsType<CSharpStatementIRNode>(n));
         }
+
+        [Fact]
+        public void Execute_CanInitializeDefaults()
+        {
+            // Arrange
+            var irDocument = new DocumentIRNode();
+
+            var builder = RazorIRBuilder.Create(irDocument);
+            builder.Add(new HtmlContentIRNode());
+            builder.Add(new CSharpStatementIRNode());
+
+            var pass = new TestDocumentClassifierPass()
+            {
+                Engine = RazorEngine.CreateEmpty(b => { }),
+                Namespace = "TestNamespace",
+                Class = "TestClass",
+                Method = "TestMethod",
+            };
+
+            // Act
+            pass.Execute(TestRazorCodeDocument.CreateEmpty(), irDocument);
+
+            // Assert
+            var @namespace = SingleChild<NamespaceDeclarationIRNode>(irDocument);
+            Assert.Equal("TestNamespace", @namespace.Content);
+
+            var @class = SingleChild<ClassDeclarationIRNode>(@namespace);
+            Assert.Equal("TestClass", @class.Name);
+
+            var method = SingleChild<RazorMethodDeclarationIRNode>(@class);
+            Assert.Equal("TestMethod", method.Name);
+        }
+
+        private class TestDocumentClassifierPass : DocumentClassifierPassBase
+        {
+            public bool ShouldMatch { get; set; } = true;
+
+            public string Namespace { get; set;  }
+
+            public string Class { get; set; }
+
+            public string Method { get; set; }
+
+            protected override string DocumentKind => "test";
+
+            protected override bool IsMatch(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
+            {
+                return ShouldMatch;
+            }
+
+            protected override void OnDocumentStructureCreated(
+                RazorCodeDocument codeDocument,
+                NamespaceDeclarationIRNode @namespace,
+                ClassDeclarationIRNode @class,
+                RazorMethodDeclarationIRNode method)
+            {
+                @namespace.Content = Namespace;
+                @class.Name = Class;
+                @method.Name = Method;
+            }
+        }
     }
 }

test/Microsoft.AspNetCore.Razor.Evolution.Test/RazorEngineTest.cs

@@ -139,7 +139,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 feature => Assert.IsType<DefaultDirectiveSyntaxTreePass>(feature),
                 feature => Assert.IsType<HtmlNodeOptimizationPass>(feature),
                 feature => Assert.IsType<TagHelperBinderSyntaxTreePass>(feature),
-                feature => Assert.IsType<DefaultDocumentClassifier>(feature),
+                feature => Assert.IsType<DefaultDocumentClassifierPass>(feature),
                 feature => Assert.IsType<DefaultDirectiveIRPass>(feature),
                 feature => Assert.IsType<RazorPreallocatedTagHelperAttributeOptimizationPass>(feature));
         }
@@ -162,7 +162,7 @@ namespace Microsoft.AspNetCore.Razor.Evolution
                 feature => Assert.IsType<DefaultDirectiveSyntaxTreePass>(feature),
                 feature => Assert.IsType<HtmlNodeOptimizationPass>(feature),
                 feature => Assert.IsType<TagHelperBinderSyntaxTreePass>(feature),
-                feature => Assert.IsType<DefaultDocumentClassifier>(feature),
+                feature => Assert.IsType<DefaultDocumentClassifierPass>(feature),
                 feature => Assert.IsType<DefaultDirectiveIRPass>(feature),
                 feature => Assert.IsType<RazorEngine.ConfigureDesignTimeOptions>(feature),
                 feature => Assert.IsType<RazorDesignTimeIRPass>(feature));