C#: Address review comments. Replace GetHashValue() with MetadataTokens.GetToken().

C#: Make path IDs consistent.

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

@@ -4,6 +4,7 @@ using System.Linq;
 using Microsoft.CodeAnalysis;
 using System.Reflection.Metadata;
 using System.Reflection;
+using System.Reflection.Metadata.Ecma335;
 
 namespace Semmle.Extraction.CIL.Entities
 {
@@ -88,7 +89,7 @@ namespace Semmle.Extraction.CIL.Entities
         {
             get
             {
-                yield return Tuples.metadata_handle(this, cx.assembly, handle.GetHashCode());
+                yield return Tuples.metadata_handle(this, cx.assembly, MetadataTokens.GetToken(handle));
 
                 foreach (var c in base.Contents)
                     yield return c;

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

@@ -16,8 +16,8 @@ namespace Semmle.Extraction.CIL.Entities
 
         public File(Context cx, string path) : base(cx)
         {
-            this.path = path.Replace("\\", "/");
-            ShortId = new StringId(path.Replace(":", "_"));
+            this.path = path;
+            ShortId = new StringId(Semmle.Extraction.Entities.File.PathAsDatabaseId(path));
         }
 
         public override IEnumerable<IExtractionProduct> Contents
@@ -27,7 +27,7 @@ namespace Semmle.Extraction.CIL.Entities
                 var parent = cx.CreateFolder(System.IO.Path.GetDirectoryName(path));
                 yield return parent;
                 yield return Tuples.containerparent(parent, this);
-                yield return Tuples.files(this, path, System.IO.Path.GetFileNameWithoutExtension(path), System.IO.Path.GetExtension(path).Substring(1));
+                yield return Tuples.files(this, Semmle.Extraction.Entities.File.PathAsDatabaseString(path), System.IO.Path.GetFileNameWithoutExtension(path), System.IO.Path.GetExtension(path).Substring(1));
             }
         }
 

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

@@ -14,7 +14,7 @@ namespace Semmle.Extraction.CIL.Entities
         public Folder(Context cx, string path) : base(cx)
         {
             this.path = path;
-            ShortId = new StringId(path.Replace("\\", "/").Replace(":", "_"));
+            ShortId = new StringId(Semmle.Extraction.Entities.File.PathAsDatabaseId(path));
         }
 
         static readonly Id suffix = new StringId(";folder");
@@ -33,7 +33,7 @@ namespace Semmle.Extraction.CIL.Entities
                     yield return parentFolder;
                     yield return Tuples.containerparent(parentFolder, this);
                 }
-                yield return Tuples.folders(this, path, Path.GetFileName(path));
+                yield return Tuples.folders(this, Semmle.Extraction.Entities.File.PathAsDatabaseString(path), Path.GetFileName(path));
             }
         }
 

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

@@ -5,6 +5,7 @@ using Microsoft.CodeAnalysis;
 using System.Collections.Generic;
 using System.Reflection;
 using System.Linq;
+using System.Reflection.Metadata.Ecma335;
 
 namespace Semmle.Extraction.CIL.Entities
 {
@@ -207,7 +208,7 @@ namespace Semmle.Extraction.CIL.Entities
                     Attribute.Populate(cx, pe, p.GetCustomAttributes());
                 }
 
-                yield return Tuples.metadata_handle(this, cx.assembly, handle.GetHashCode());
+                yield return Tuples.metadata_handle(this, cx.assembly, MetadataTokens.GetToken(handle));
                 yield return Tuples.cil_method(this, Name, declaringType, typeSignature.ReturnType);
                 yield return Tuples.cil_method_source_declaration(this, this);
                 yield return Tuples.cil_method_location(this, cx.assembly);

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

@@ -1,6 +1,7 @@
 using System.Collections.Generic;
 using System.Reflection.Metadata;
 using System.Linq;
+using System.Reflection.Metadata.Ecma335;
 
 namespace Semmle.Extraction.CIL.Entities
 {
@@ -37,7 +38,7 @@ namespace Semmle.Extraction.CIL.Entities
         {
             get
             {
-                yield return Tuples.metadata_handle(this, cx.assembly, handle.GetHashCode());
+                yield return Tuples.metadata_handle(this, cx.assembly, MetadataTokens.GetToken(handle));
                 var sig = pd.DecodeSignature(cx.TypeSignatureDecoder, type);
 
                 yield return Tuples.cil_property(this, type, cx.ShortName(pd.Name), sig.ReturnType);

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

@@ -248,7 +248,7 @@ namespace Semmle.Extraction.CIL.Entities
     /// </summary>
     public sealed class TypeDefinitionType : Type
     {
-        Handle handle;
+        readonly Handle handle;
         readonly TypeDefinition td;
 
         public TypeDefinitionType(Context cx, TypeDefinitionHandle handle) : base(cx)

csharp/extractor/Semmle.Extraction.CSharp/Entities/Symbol.cs

@@ -4,6 +4,7 @@ using Semmle.Extraction.Entities;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection.Metadata;
+using System.Reflection.Metadata.Ecma335;
 
 namespace Semmle.Extraction.CSharp.Entities
 {
@@ -103,11 +104,12 @@ namespace Semmle.Extraction.CSharp.Entities
         protected void ExtractMetadataHandle()
         {
             var handle = MetadataHandle;
-            if (!handle.IsNil)
-                Context.Emit(Tuples.metadata_handle(this, Location, handle.GetHashCode()));
+
+            if (handle.HasValue)
+                Context.Emit(Tuples.metadata_handle(this, Location, MetadataTokens.GetToken(handle.Value)));
         }
 
-        public Handle MetadataHandle
+        public Handle? MetadataHandle
         {
             get
             {
@@ -122,21 +124,21 @@ namespace Semmle.Extraction.CSharp.Entities
                     {
                         return (MethodDefinitionHandle)value;
                     }
-                    else if(value is TypeDefinitionHandle)
+                    else if (value is TypeDefinitionHandle)
                     {
                         return (TypeDefinitionHandle)value;
                     }
-                    else if(value is PropertyDefinitionHandle)
+                    else if (value is PropertyDefinitionHandle)
                     {
                         return (PropertyDefinitionHandle)value;
                     }
-                    else if(value is FieldDefinitionHandle)
+                    else if (value is FieldDefinitionHandle)
                     {
                         return (FieldDefinitionHandle)value;
                     }
                 }
 
-                return new Handle(); // A nil handle
+                return null;
             }
         }
     }

csharp/extractor/Semmle.Extraction/Entities/File.cs

@@ -19,7 +19,7 @@ namespace Semmle.Extraction.Entities
             private set;
         }
 
-        public string DatabasePath => FileAsDatabaseString(Path);
+        public string DatabasePath => PathAsDatabaseId(Path);
 
         public override bool NeedsPopulation => Context.DefinesFile(Path) || Path == Context.Extractor.OutputPath;
 
@@ -41,7 +41,7 @@ namespace Semmle.Extraction.Entities
                 // remove the dot from the extension
                 if (extension.Length > 0)
                     extension = extension.Substring(1);
-                Context.Emit(Tuples.files(this, DatabasePath, name, extension));
+                Context.Emit(Tuples.files(this, PathAsDatabaseString(Path), name, extension));
 
                 Context.Emit(Tuples.containerparent(Entities.Folder.Create(Context, fi.Directory), this));
                 if (fromSource == 1)
@@ -73,14 +73,21 @@ namespace Semmle.Extraction.Entities
             }
         }
 
-        internal static string FileAsDatabaseString(string fileName)
+        /// <summary>
+        /// Converts a path string into a string to use as an ID
+        /// in the QL database.
+        /// </summary>
+        /// <param name="path">An absolute path.</param>
+        /// <returns>The database ID.</returns>
+        public static string PathAsDatabaseId(string path)
         {
-            fileName = fileName.Replace('\\', '/');
-            if (fileName.Length > 1 && fileName[1] == ':')
-                fileName = Char.ToUpper(fileName[0]) + fileName.Substring(1);
-            return fileName;
+            if (path.Length >= 2 && path[1] == ':' && Char.IsLower(path[0]))
+                path = Char.ToUpper(path[0]) + "_" + path.Substring(2);
+            return path.Replace('\\', '/').Replace(":", "_");
         }
 
+        public static string PathAsDatabaseString(string path) => path.Replace('\\', '/');
+
         public static File Create(Context cx, string path) => FileFactory.Instance.CreateEntity(cx, path);
 
         public static File CreateGenerated(Context cx) => GeneratedFile.Create(cx);

csharp/extractor/Semmle.Extraction/Entities/Folder.cs

@@ -16,7 +16,7 @@ namespace Semmle.Extraction.Entities
             private set;
         }
 
-        public string DatabasePath => File.FileAsDatabaseString(Path);
+        public string DatabasePath => File.PathAsDatabaseId(Path);
 
         public override void Populate()
         {
@@ -27,7 +27,7 @@ namespace Semmle.Extraction.Entities
             // On Windows: System.IO.DirectoryInfo.Name returns "L:\"
             string shortName = symbol.Parent == null ? "" : symbol.Name;
 
-            Context.Emit(Tuples.folders(this, DatabasePath, shortName));
+            Context.Emit(Tuples.folders(this, Semmle.Extraction.Entities.File.PathAsDatabaseString(Path), shortName));
             if (symbol.Parent != null)
             {
                 Context.Emit(Tuples.containerparent(Create(Context, symbol.Parent), this));

csharp/ql/test/library-tests/cil/consistency/Handles.ql

@@ -11,7 +11,7 @@ class MetadataEntity extends DotNet::NamedElement, @metadata_entity {
 }
 
 query predicate tooManyMatchingHandles(MetadataEntity e) {
-  count(MetadataEntity e2 | e.matchesHandle(e2))>2
+  strictcount(MetadataEntity e2 | e.matchesHandle(e2)) > 2
 }
 
 query predicate missingCil(Element e) {