Merge pull request github#5144 from tamasvajk/feature/refactor-2

C# Share entity base classes between CIL and source extraction

Author: tamasvajk

csharp/extractor/Semmle.Extraction.CIL/Context.Factories.cs

@@ -95,11 +95,11 @@ public PrimitiveType Create(PrimitiveTypeCode code)
         /// <param name="h">The handle of the entity.</param>
         /// <param name="genericContext">The generic context.</param>
         /// <returns></returns>
-        public IExtractedEntity CreateGeneric(GenericContext genericContext, Handle h) => genericHandleFactory[genericContext, h];
+        public IExtractedEntity CreateGeneric(IGenericContext genericContext, Handle h) => genericHandleFactory[genericContext, h];
 
-        private readonly GenericContext defaultGenericContext;
+        private readonly IGenericContext defaultGenericContext;
 
-        private IExtractedEntity CreateGenericHandle(GenericContext gc, Handle handle)
+        private IExtractedEntity CreateGenericHandle(IGenericContext gc, Handle handle)
         {
             IExtractedEntity entity;
             switch (handle.Kind)
@@ -136,7 +136,7 @@ private IExtractedEntity CreateGenericHandle(GenericContext gc, Handle handle)
             return entity;
         }
 
-        private IExtractedEntity Create(GenericContext gc, MemberReferenceHandle handle)
+        private IExtractedEntity Create(IGenericContext gc, MemberReferenceHandle handle)
         {
             var mr = MdReader.GetMemberReference(handle);
             switch (mr.GetKind())
@@ -228,7 +228,7 @@ private Namespace CreateNamespace(NamespaceDefinitionHandle handle)
 
         #endregion
 
-        private readonly CachedFunction<GenericContext, Handle, IExtractedEntity> genericHandleFactory;
+        private readonly CachedFunction<IGenericContext, Handle, IExtractedEntity> genericHandleFactory;
 
         /// <summary>
         /// Gets the short name of a member, without the preceding interface qualifier.

csharp/extractor/Semmle.Extraction.CIL/Context.cs

@@ -37,7 +37,7 @@ public Context(Extraction.Context cx, string assemblyPath, bool extractPdbs)
 
             globalNamespace = new Lazy<Entities.Namespace>(() => Populate(new Entities.Namespace(this, "", null)));
             systemNamespace = new Lazy<Entities.Namespace>(() => Populate(new Entities.Namespace(this, "System")));
-            genericHandleFactory = new CachedFunction<GenericContext, Handle, IExtractedEntity>(CreateGenericHandle);
+            genericHandleFactory = new CachedFunction<IGenericContext, Handle, IExtractedEntity>(CreateGenericHandle);
             namespaceFactory = new CachedFunction<StringHandle, Entities.Namespace>(n => CreateNamespace(MdReader.GetString(n)));
             namespaceDefinitionFactory = new CachedFunction<NamespaceDefinitionHandle, Entities.Namespace>(CreateNamespace);
             sourceFiles = new CachedFunction<PDB.ISourceFile, Entities.PdbSourceFile>(path => new Entities.PdbSourceFile(this, path));

csharp/extractor/Semmle.Extraction.CIL/EmptyContext.cs

@@ -5,14 +5,18 @@ namespace Semmle.Extraction.CIL
     /// <summary>
     /// A generic context which does not contain any type parameters.
     /// </summary>
-    public class EmptyContext : GenericContext
+    public class EmptyContext : IGenericContext
     {
-        public EmptyContext(Context cx) : base(cx)
+        public EmptyContext(Context cx)
         {
+            Cx = cx;
         }
 
-        public override IEnumerable<Entities.Type> TypeParameters { get { yield break; } }
+        public Context Cx { get; }
+
+        public IEnumerable<Entities.Type> TypeParameters { get { yield break; } }
+
+        public IEnumerable<Entities.Type> MethodParameters { get { yield break; } }
 
-        public override IEnumerable<Entities.Type> MethodParameters { get { yield break; } }
     }
 }

csharp/extractor/Semmle.Extraction.CIL/Entities/Assembly.cs

@@ -40,6 +40,7 @@ public override void WriteId(TextWriter trapFile)
             trapFile.Write(FullName);
             trapFile.Write("#file:///");
             trapFile.Write(Cx.AssemblyPath.Replace("\\", "/"));
+            trapFile.Write(";assembly");
         }
 
         public override bool Equals(object? obj)
@@ -49,8 +50,6 @@ public override bool Equals(object? obj)
 
         public override int GetHashCode() => 7 * file.GetHashCode();
 
-        public override string IdSuffix => ";assembly";
-
         private string FullName => assemblyName.GetPublicKey() is null ? assemblyName.FullName + ", PublicKeyToken=null" : assemblyName.FullName;
 
         public override IEnumerable<IExtractionProduct> Contents

csharp/extractor/Semmle.Extraction.CIL/Entities/Attribute.cs

@@ -12,9 +12,9 @@ internal sealed class Attribute : UnlabelledEntity
     {
         private readonly CustomAttributeHandle handle;
         private readonly CustomAttribute attrib;
-        private readonly IEntity @object;
+        private readonly IExtractedEntity @object;
 
-        public Attribute(Context cx, IEntity @object, CustomAttributeHandle handle) : base(cx)
+        public Attribute(Context cx, IExtractedEntity @object, CustomAttributeHandle handle) : base(cx)
         {
             attrib = cx.MdReader.GetCustomAttribute(handle);
             this.handle = handle;
@@ -80,7 +80,7 @@ private static string GetStringValue(Type type, object? value)
             return value?.ToString() ?? "null";
         }
 
-        public static IEnumerable<IExtractionProduct> Populate(Context cx, IEntity @object, CustomAttributeHandleCollection attributes)
+        public static IEnumerable<IExtractionProduct> Populate(Context cx, IExtractedEntity @object, CustomAttributeHandleCollection attributes)
         {
             foreach (var attrib in attributes)
             {

csharp/extractor/Semmle.Extraction.CIL/Entities/Base/IExtractedEntity.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+
+namespace Semmle.Extraction.CIL
+{
+    /// <summary>
+    /// A CIL entity which has been extracted.
+    /// </summary>
+    public interface IExtractedEntity : IExtractionProduct, IEntity
+    {
+        /// <summary>
+        /// The contents of the entity.
+        /// </summary>
+
+        IEnumerable<IExtractionProduct> Contents { get; }
+    }
+}

csharp/extractor/Semmle.Extraction.CIL/Entities/Base/IExtractionProduct.cs

@@ -0,0 +1,24 @@
+namespace Semmle.Extraction.CIL
+{
+    /// <summary>
+    /// Something that is extracted from an entity.
+    /// </summary>
+    ///
+    /// <remarks>
+    /// The extraction algorithm proceeds as follows:
+    /// - Construct entity
+    /// - Call Extract()
+    /// - IExtractedEntity check if already extracted
+    /// - Enumerate Contents to produce more extraction products
+    /// - Extract these until there is nothing left to extract
+    /// </remarks>
+    public interface IExtractionProduct
+    {
+        /// <summary>
+        /// Perform further extraction/population of this item as necessary.
+        /// </summary>
+        ///
+        /// <param name="cx">The extraction context.</param>
+        void Extract(Context cx);
+    }
+}

csharp/extractor/Semmle.Extraction.CIL/Entities/Base/IGenericContext.cs

@@ -0,0 +1,24 @@
+using System.Collections.Generic;
+
+namespace Semmle.Extraction.CIL
+{
+    /// <summary>
+    /// When we decode a type/method signature, we need access to
+    /// generic parameters.
+    /// </summary>
+    public interface IGenericContext
+    {
+        Context Cx { get; }
+
+        /// <summary>
+        /// The list of generic type parameters/arguments, including type parameters/arguments of
+        /// containing types.
+        /// </summary>
+        IEnumerable<Entities.Type> TypeParameters { get; }
+
+        /// <summary>
+        /// The list of generic method parameters/arguments.
+        /// </summary>
+        IEnumerable<Entities.Type> MethodParameters { get; }
+    }
+}

csharp/extractor/Semmle.Extraction.CIL/Entities/Base/LabelledEntity.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace Semmle.Extraction.CIL
+{
+    /// <summary>
+    /// An entity that needs to be populated during extraction.
+    /// This assigns a key and optionally extracts its contents.
+    /// </summary>
+    public abstract class LabelledEntity : Extraction.LabelledEntity, IExtractedEntity
+    {
+        // todo: with .NET 5 this can override the base context, and change the return type.
+        public Context Cx { get; }
+
+        protected LabelledEntity(Context cx) : base(cx.Cx)
+        {
+            this.Cx = cx;
+        }
+
+        public override Microsoft.CodeAnalysis.Location ReportingLocation => throw new NotImplementedException();
+
+        public void Extract(Context cx2)
+        {
+            cx2.Populate(this);
+        }
+
+        public override string ToString()
+        {
+            using var writer = new StringWriter();
+            WriteQuotedId(writer);
+            return writer.ToString();
+        }
+
+        public override TrapStackBehaviour TrapStackBehaviour => TrapStackBehaviour.NoLabel;
+
+        public abstract IEnumerable<IExtractionProduct> Contents { get; }
+    }
+}

csharp/extractor/Semmle.Extraction.CIL/Entities/Base/Tuple.cs

@@ -0,0 +1,22 @@
+namespace Semmle.Extraction.CIL
+{
+    /// <summary>
+    /// A tuple that is an extraction product.
+    /// </summary>
+    internal class Tuple : IExtractionProduct
+    {
+        private readonly Extraction.Tuple tuple;
+
+        public Tuple(string name, params object[] args)
+        {
+            tuple = new Extraction.Tuple(name, args);
+        }
+
+        public void Extract(Context cx)
+        {
+            cx.Cx.Emit(tuple);
+        }
+
+        public override string ToString() => tuple.ToString();
+    }
+}