[generator] mark obfuscated types in generator. (#92)

Fixes: https://bugzilla.xamarin.com/show_bug.cgi?id=44530

Basically this is part of the problems reported at
https://bugzilla.xamarin.com/show_bug.cgi?id=44263

In good old jar2xml era, we marked "obfuscated" types at jar2xml so
that those types are not generated in the API XML.

class-parse is not that clever and generates everything as is.

We could make changes to api-xml-adjuster to bring back sanity, but
instead of doing it in jar2xml, we had better bring in flexibility
to obfuscation marking. That is -

- If there is obfuscated='false' attribute specification by API
  metadata fixup, then do not mark as obfuscated in any case.
- If not, process any lowercase-named types and nested types as
  obfuscated, such as 'a', 'SomeType$a', or 'SomeType$b$a'.

Due to code structures, we cannot take the same code path as jar2xml
(we don't hold list of sibling classes when processing an XML element).
https://github.com/xamarin/jar2xml/blob/3a7c404/JavaPackage.java#L78

Also, we had seen some obfuscated types like b$a as NOT marked as
obfuscated in the past, because we were checking only a,aa,aaa,aaaa and
aaaaa as the parent type for nested types. That should be fixed.

To fix this issue, we process marking as part of StripNonBindables().
Also, it was too early to register those types to SymbolTable before
stripping those types out, so changed relevant processing order.

Fixing bug #44263 then exposed another problem; StripNonBindables()
was not complete and it was not processing nested C# types at all.
Thus we had generated non-bindable code before. This change fixes this
issue at the same time, for fixing the bug.

Thus, this will result in "API breakage" looking changes in the end,
but the bindings were invalid and should be removed without
compatibility concern.

Author: atsushieno

tools/generator/CodeGenerator.cs

@@ -308,8 +308,12 @@ static void Run (CodeGeneratorOptions options, DirectoryAssemblyResolver resolve
 			opt.Gens = gens;
 
 			// disable interface default methods here, especially before validation.
-			foreach (var gen in gens)
+			gens = gens.Where (g => !g.IsObfuscated && g.Visibility != "private").ToList ();
+			foreach (var gen in gens) {
 				gen.StripNonBindables ();
+				if (gen.IsGeneratable)
+					AddTypeToTable (gen);
+			}
 
 			Validate (gens, opt);
 
@@ -355,6 +359,13 @@ static void Run (CodeGeneratorOptions options, DirectoryAssemblyResolver resolve
 			gen_info.GenerateLibraryProjectFile (options, enumFiles);
 		}
 
+		static void AddTypeToTable (GenBase gb)
+		{
+			SymbolTable.AddType (gb);
+			foreach (var nt in gb.NestedTypes)
+				AddTypeToTable (nt);
+		}
+
 		static IEnumerable<GenBase> FlattenNestedTypes (IEnumerable<GenBase> gens)
 		{
 			foreach (var g in gens) {

tools/generator/GenBase.cs

@@ -53,6 +53,10 @@ public bool IsDeprecated {
 			get { return support.IsDeprecated; }
 		}
 
+		public bool IsObfuscated {
+			get { return support.IsObfuscated; }
+		}
+
 		public string DeprecatedComment {
 			get { return support.DeprecatedComment; }
 		}
@@ -718,6 +722,9 @@ public void StripNonBindables ()
 			// have to "implement" those methods because they are declared and you have to implement
 			// any declared methods in C#. That is going to be problematic a lot.
 			methods = methods.Where (m => !m.IsInterfaceDefaultMethod).ToList ();
+			nested_types = nested_types.Where (n => !n.IsObfuscated && n.Visibility != "private").ToList ();
+			foreach (var n in nested_types)
+				n.StripNonBindables ();
 		}
 
 		public void FillProperties ()

tools/generator/GenBaseSupport.cs

@@ -18,6 +18,7 @@ public abstract class GenBaseSupport
 		public abstract string DeprecatedComment { get; }
 		public abstract bool IsGeneratable { get; }
 		public abstract bool IsGeneric { get; }
+		public abstract bool IsObfuscated { get; }
 		public abstract string FullName { get; set; }
 		public abstract string Name { get; set; }
 		public abstract string Namespace { get; }
@@ -92,6 +93,10 @@ public override bool IsAcw {
 		public override bool IsDeprecated {
 			get { return deprecated; }
 		}
+
+		public override bool IsObfuscated {
+			get { return false; } // obfuscated types have no chance to be already bound in managed types.
+		}
 
 		public override string DeprecatedComment {
 			get { return deprecatedComment; }
@@ -198,8 +203,8 @@ public XmlGenBaseSupport (XmlElement pkg, XmlElement elem)
 				name = TypeNamePrefix + raw_name;
 				full_name = String.Format ("{0}.{1}{2}", ns, idx > 0 ? StringRocks.TypeToPascalCase (java_name.Substring (0, idx + 1)) : String.Empty, name);
 			}
-			//marshaler = elem.XGetAttribute ("marshaler");
-			//if (!string.IsNullOrEmpty (marshaler)) throw new Exception ();
+
+			obfuscated = IsObfuscatedName (java_name) && elem.XGetAttribute ("obfuscated") != "false";
 		}
 
 		public override bool IsAcw {
@@ -219,6 +224,11 @@ public override string DeprecatedComment {
 		public override bool IsGeneratable {
 			get { return true; }
 		}
+
+		bool obfuscated;
+		public override bool IsObfuscated {
+			get { return obfuscated; }
+		}
 
 		string java_name;
 		public override string JavaSimpleName {
@@ -291,6 +301,17 @@ public override bool ValidateNamespace ()
 			}
 			return true;
 		}
+
+		bool IsObfuscatedName (String name)
+		{
+			if (name.StartsWith ("R.", StringComparison.Ordinal))
+				return false;
+			int idx = name.LastIndexOf ('.');
+			string last = idx < 0 ? name : name.Substring (idx + 1);
+			if (last.Any (c => (c < 'a' || 'z' < c) && (c < '0' || '9' < c)))
+					return false;
+			return true;
+		}
 	}
 
 	public class InterfaceXmlGenBaseSupport : XmlGenBaseSupport

tools/generator/Parser.cs

@@ -129,7 +129,6 @@ List<GenBase> ParsePackage (XmlElement ns, Predicate<XmlElement> p)
 					nested [name] = gen;
 				else
 					result.Add (gen);
-				SymbolTable.AddType (gen);
 			}
 
 			foreach (string name in nested.Keys) {