Share entity base classes between CIL and source extraction

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();
+    }
+}

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

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+
+namespace Semmle.Extraction.CIL
+{
+    /// <summary>
+    /// An entity that has contents to extract. There is no need to populate
+    /// a key as it's done in the contructor.
+    /// </summary>
+    public abstract class UnlabelledEntity : Extraction.UnlabelledEntity, IExtractedEntity
+    {
+        // todo: with .NET 5 this can override the base context, and change the return type.
+        public Context Cx { get; }
+
+        protected UnlabelledEntity(Context cx) : base(cx.Cx)
+        {
+            Cx = cx;
+        }
+
+        public override Microsoft.CodeAnalysis.Location ReportingLocation => throw new NotImplementedException();
+
+        public void Extract(Context cx2)
+        {
+            cx2.Extract(this);
+        }
+
+        public override TrapStackBehaviour TrapStackBehaviour => TrapStackBehaviour.NoLabel;
+
+        public abstract IEnumerable<IExtractionProduct> Contents { get; }
+    }
+}