Collect overridden Java methods in JCW

Marshal methods generator in Xamarin.Android needs to know
which Java methods in which types are overridden by the application.

Package name, method name and signature are all require to generate
correct name of the native symbol which will be found by JNI at the
run time.

Author: grendello

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaCallableWrapperGenerator.cs

@@ -25,6 +25,36 @@ public enum JavaPeerStyle {
 		JavaInterop1,
 	}
 
+	public class OverriddenMethodDescriptor
+	{
+		static readonly char[] methodDescSplitChars = new char[] { ':' };
+
+		public string JavaPackageName { get; }
+		public string NativeName      { get; }
+		public string JniSignature    { get; }
+		public string Connector       { get; }
+		public string ManagedTypeName { get; }
+
+		public OverriddenMethodDescriptor (string javaPackageName, string methodDescription)
+		{
+			JavaPackageName = javaPackageName;
+			string[] parts = methodDescription.Split (methodDescSplitChars, 4);
+
+			if (parts.Length < 2) {
+				throw new InvalidOperationException ($"Unexpected format for method description. Expected at least 2 parts, got {parts.Length} from: '{methodDescription}'");
+			}
+
+			NativeName = parts[0];
+			JniSignature = parts[1];
+			if (parts.Length > 2) {
+				Connector = parts[2];
+				if (parts.Length > 3) {
+					ManagedTypeName = parts[3];
+				}
+			}
+		}
+	}
+
 	 public class JavaCallableWrapperGenerator {
 
 		class JavaFieldInfo {
@@ -59,6 +89,7 @@ public string GetJavaAccess ()
 		List<Signature> methods = new List<Signature> ();
 		List<Signature> ctors   = new List<Signature> ();
 		List<JavaCallableWrapperGenerator> children;
+		List<OverriddenMethodDescriptor> overriddenMethodDescriptors;
 		readonly IMetadataResolver cache;
 
 		[Obsolete ("Use the TypeDefinitionCache overload for better performance.")]
@@ -80,6 +111,7 @@ public JavaCallableWrapperGenerator (TypeDefinition type, Action<string, object[
 			}
 		}
 
+		public  IList<OverriddenMethodDescriptor> OverriddenMethodDescriptors => overriddenMethodDescriptors;
 		public  string          ApplicationJavaClass            { get; set; }
 		public  JavaPeerStyle   CodeGenerationTarget            { get; set; }
 
@@ -89,7 +121,7 @@ public JavaCallableWrapperGenerator (TypeDefinition type, Action<string, object[
 
 		/// <summary>
 		/// The Java source code to be included in Instrumentation.onCreate
-		/// 
+		///
 		/// Originally came from MonoRuntimeProvider.java delimited by:
 		/// // Mono Runtime Initialization {{{
 		/// // }}}
@@ -497,6 +529,7 @@ string GetManagedParameters (MethodDefinition ctor, string outerType)
 
 		public void Generate (TextWriter writer)
 		{
+			overriddenMethodDescriptors = new List<OverriddenMethodDescriptor> ();
 			if (!string.IsNullOrEmpty (package)) {
 				writer.WriteLine ("package " + package + ";");
 				writer.WriteLine ();
@@ -530,6 +563,17 @@ public void Generate (TextWriter writer)
 				}
 
 			GenerateFooter (writer);
+
+			string javaTypeName = $"{package}.{name}";
+			AddOverridenMethods (methods);
+			AddOverridenMethods (ctors);
+
+			void AddOverridenMethods (List<Signature> list)
+			{
+				foreach (Signature sig in list) {
+					overriddenMethodDescriptors.Add (new OverriddenMethodDescriptor (javaTypeName, sig.Method));
+				}
+			}
 		}
 
 		public void Generate (string outputPath)
@@ -958,5 +1002,3 @@ public string GetDestinationPath (string outputPath)
 		}
 	}
 }
-
-