[.JavaSource, .ApiXmlAdjuster] Use Nullable Reference Types (#746)

Update `Java.Interop.Tools.JavaSource.dll` and
`Xamarin.Android.Tools.ApiXmlAdjuster.dll` so that
C# 8 [Nullable Reference Types][0] are used.
[0]: https://docs.microsoft.com/dotnet/csharp/nullable-references

Author: jonpryor

src/Java.Interop.Tools.JavaSource/Java.Interop.Tools.JavaSource.csproj

@@ -2,6 +2,9 @@
 <ProjectSdk="Microsoft.NET.Sdk">
  <PropertyGroup>
  <TargetFramework>netstandard2.0</TargetFramework>
+ <LangVersion>8.0</LangVersion>
+ <Nullable>enable</Nullable>
+ <DefineConstants>INTERNAL_NULLABLE_ATTRIBUTES</DefineConstants>
  <ProjectGuid>{5C0B3562-8DA0-4726-9762-75B9709ED6B7}</ProjectGuid>
  <AssemblyTitle>Java.Interop.Tools.JavaSource</AssemblyTitle>
  <Company>Microsoft Corporation</Company>
@@ -11,6 +14,9 @@
  <PropertyGroup>
  <OutputPath>$(ToolOutputFullPath)</OutputPath>
  </PropertyGroup>
+ <ItemGroup>
+ <CompileInclude="..\utils\NullableAttributes.cs" />
+ </ItemGroup>
  <ItemGroup>
  <PackageReferenceInclude="Irony"Version="1.1.0" />
  </ItemGroup>

src/Java.Interop.Tools.JavaSource/Java.Interop.Tools.JavaSource/JavaStubParser.cs

@@ -421,7 +421,9 @@ public JavaStubGrammar ()
 varpackageTokens=s.Split('.').TakeWhile(t =>!t.Any(c =>Char.IsUpper(c)));
 returns.Substring(Enumerable.Sum(packageTokens.Select(t =>t.Length))+packageTokens.Count());
 };
-method.Exceptions=((IEnumerable<string>)node.ChildNodes[ctor?6:7].AstNode)?.Select(s =>newJavaException{Type=s,Name=stripPackage(s)})?.ToArray();
+method.Exceptions=((IEnumerable<string>)node.ChildNodes[ctor?6:7].AstNode)
+?.Select(s =>newJavaException{Type=s,Name=stripPackage(s)})
+?.ToArray();
 method.Deprecated=((IEnumerable<string>)node.ChildNodes[0].AstNode).Any(v =>v=="java.lang.Deprecated"||v=="Deprecated")?"deprecated":"not deprecated";
 method.Final=mods.Contains("final");
 method.TypeParameters=modsOrTps.OfType<JavaTypeParameters>().FirstOrDefault();
@@ -501,7 +503,7 @@ public JavaStubGrammar ()
 assignment.AstConfig.NodeCreator=SelectChildValueAt(0);
 assign_expr.AstConfig.NodeCreator=(ctx,node)=>{
 ProcessChildren(ctx,node);
-node.AstNode=newKeyValuePair<string,string>((string)node.ChildNodes[0].AstNode,node.ChildNodes[2].AstNode?.ToString());
+node.AstNode=newKeyValuePair<string,string?>((string)node.ChildNodes[0].AstNode,node.ChildNodes[2].AstNode?.ToString());
 };
 rvalue_expressions.AstConfig.NodeCreator=CreateArrayCreator<object>();
 rvalue_expression.AstConfig.NodeCreator=SelectSingleChild;
@@ -542,7 +544,7 @@ public JavaStubGrammar ()
 };
 generic_definition_arguments.AstConfig.NodeCreator=(ctx,node)=>{
 ProcessChildren(ctx,node);
-node.AstNode=newJavaTypeParameters((JavaMethod)null){TypeParameters=node.ChildNodes.Select(c =>c.AstNode).Cast<JavaTypeParameter>().ToList()};
+node.AstNode=newJavaTypeParameters((JavaMethod?)null){TypeParameters=node.ChildNodes.Select(c =>c.AstNode).Cast<JavaTypeParameter>().ToList()};
 };
 generic_definition_argument.AstConfig.NodeCreator=(ctx,node)=>{
 ProcessChildren(ctx,node);
@@ -557,7 +559,7 @@ public JavaStubGrammar ()
 generic_instance_identifier_or_q.AstConfig.NodeCreator=SelectSingleChild;
 generic_instance_constraints.AstConfig.NodeCreator=(ctx,node)=>{
 ProcessChildren(ctx,node);
-varc=(JavaGenericConstraints)node.ChildNodes.FirstOrDefault()?.AstNode;
+varc=(JavaGenericConstraints?)node.ChildNodes.FirstOrDefault()?.AstNode;
 if(c!=null)
 node.AstNode=" "+c.BoundsType+" "+string.Join(" & ",c.GenericConstraints.Select(cc =>cc.Type));
 };
@@ -602,27 +604,27 @@ public JavaStubParser ()
 
 }
 
-publicJavaPackageTryLoad(stringuri)
+publicJavaPackage?TryLoad(stringuri)
 {
 returnTryLoad(uri,outvar_);
 }
 
-publicJavaPackageTryLoad(stringuri,outParseTreeparseTree)
+publicJavaPackage?TryLoad(stringuri,outParseTreeparseTree)
 {
 returnTryParse(File.ReadAllText(uri),uri,outparseTree);
 }
 
-publicJavaPackageTryParse(stringtext)
+publicJavaPackage?TryParse(stringtext)
 {
 returnTryParse(text,null,outvar_);
 }
 
-publicJavaPackageTryParse(stringtext,outParseTreeparseTree)
+publicJavaPackage?TryParse(stringtext,outParseTreeparseTree)
 {
 returnTryParse(text,null,outparseTree);
 }
 
-publicJavaPackageTryParse(stringtext,stringfileName,outParseTreeparseTree)
+publicJavaPackage?TryParse(stringtext,string?fileName,outParseTreeparseTree)
 {
 parseTree=base.Parse(text,fileName);
 if(parseTree.HasErrors())
@@ -634,32 +636,35 @@ public JavaPackage TryParse (string text, string fileName, out ParseTree parseTr
 
 voidFlattenNestedTypes(JavaPackagepackage)
 {
-Action<List<JavaType>,JavaType>flatten=null;
-flatten=(list,t)=>{
+varresults=newList<JavaType>();
+foreach(vartinpackage.Types)
+Flatten(results,t);
+package.Types=results.ToList();
+
+voidFlatten(List<JavaType>list,JavaTypet)
+{
 list.Add(t);
 foreach(varntint.Members.OfType<JavaNestedType>()){
+if(nt.Type==null)
+continue;
 nt.Type.Name=t.Name+'.'+nt.Type.Name;
 foreach(varncinnt.Type.Members.OfType<JavaConstructor>())
 nc.Name=nt.Type.Name;
-flatten(list,nt.Type);
+Flatten(list,nt.Type);
 }
 t.Members=t.Members.Where(_ =>!(_isJavaNestedType)).ToArray();
-};
-varresults=newList<JavaType>();
-foreach(vartinpackage.Types)
-flatten(results,t);
-package.Types=results.ToList();
+}
 }
 }
 
 classJavaNestedType:JavaMember
 {
-publicJavaNestedType(JavaTypetype)
+publicJavaNestedType(JavaType?type)
 :base(type)
 {
 }
 
-publicJavaTypeType{get;set;}
+publicJavaType?Type{get;set;}
 }
 }
 

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApi.RelationAnalysisModel.cs

@@ -7,47 +7,48 @@ namespace Xamarin.Android.Tools.ApiXmlAdjuster
 
 publicpartialclassJavaClass
 {
-publicJavaTypeReferenceResolvedExtends{get;set;}
+publicJavaTypeReference?ResolvedExtends{get;set;}
 }
 
 publicpartialclassJavaImplements
 {
-publicJavaTypeReferenceResolvedName{get;set;}
+publicJavaTypeReference?ResolvedName{get;set;}
 }
 
 publicpartialclassJavaField
 {
-publicJavaTypeReferenceResolvedType{get;set;}
+publicJavaTypeReference?ResolvedType{get;set;}
 }
 
 publicpartialclassJavaMethod
 {
-publicJavaTypeReferenceResolvedReturnType{get;set;}
+publicJavaTypeReference?ResolvedReturnType{get;set;}
 }
 
 publicpartialclassJavaParameter
 {
-publicJavaTypeReferenceResolvedType{get;set;}
+publicJavaTypeReference?ResolvedType{get;set;}
 }
 
 publicpartialclassJavaGenericConstraint
 {
-publicJavaTypeReferenceResolvedType{get;set;}
+publicJavaTypeReference?ResolvedType{get;set;}
 }
 
 // GenericInheritanceMapper extensibility
 
 publicpartialclassJavaClass
 {
-publicIDictionary<JavaTypeReference,JavaTypeReference>GenericInheritanceMapping{get;set;}
+publicIDictionary<JavaTypeReference,JavaTypeReference>?
+GenericInheritanceMapping{get;set;}
 }
 
 // OverrideMarker extensibility
 
 publicpartialclassJavaMethod
 {
-publicJavaMethodReferenceBaseMethod{get;set;}
-publicIList<JavaInterface>ImplementedInterfaces{get;set;}
+publicJavaMethodReference?BaseMethod{get;set;}
+publicIList<JavaInterface>?ImplementedInterfaces{get;set;}
 }
 
 publicpartialclassJavaMethodReference
@@ -57,12 +58,12 @@ public JavaMethodReference (JavaMethod candidate)
 this.Method=candidate;
 }
 
-publicJavaMethodMethod{get;set;}
+publicJavaMethod?Method{get;set;}
 }
 
 publicpartialclassJavaParameter
 {
-publicstringInstantiatedGenericArgumentName{get;set;}
+publicstring?InstantiatedGenericArgumentName{get;set;}
 }
 }