[Xamarin.Android.Build.Tasks] move <GenerateTypeMaps/> into <GenerateJavaStubs/>

95afa4d originally split up `<GenerateJavaStubs/>` and moved the
typemap generation to a new target. Unfortunately, this is causing
some of the build performance tests to fail:

    Build_CSharp_Change
    Exceeded expected time of 4100ms, actual 5460ms

This would be equivalent to editing `MainActivity.cs` and doing an
incremental build.

If we remove the `<GenerateTypeMaps/>` MSBuild task and keep the logic
in `<GenerateJavaStubs/>`, then we can reuse the
`DirectoryAssemblyResolver` and any `AssemblyDefinition` already
loaded in memory.

We can tackle splitting up `<GenerateJavaStubs/>` at a later date.

I also had to allow `supportedAbis` to be an empty list, as this
happens during the designer's MSBuild targets.

Author: jonathanpeppers

.external

@@ -1,3 +1,2 @@
 xamarin/monodroid:master@01a4e0a0c436bf1b0b62acf870cc06e67e62034c
 mono/mono:2019-12@8b72dbb708681fbde7f0da13fe76d128d62f8686
-

src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Designer.targets

@@ -86,6 +86,8 @@ Copyright (C) 2016 Xamarin. All rights reserved.
       AndroidSdkDir="$(_AndroidSdkDirectory)"
       PackageName="$(_AndroidPackage)"
       OutputDirectory="$(IntermediateOutputPath)android"
+      TypemapOutputDirectory="$(_NativeAssemblySourceDir)"
+      GenerateNativeAssembly="false"
       MergedAndroidManifestOutput="$(_ManifestOutput)"
       UseSharedRuntime="$(AndroidUseSharedRuntime)"
       EmbedAssemblies="$(EmbedAssembliesIntoApk)"

src/Xamarin.Android.Build.Tasks/Tasks/GenerateJavaStubs.cs

@@ -42,6 +42,12 @@ public class GenerateJavaStubs : AndroidTask
 		[Required]
 		public string [] SupportedAbis { get; set; }
 
+		[Required]
+		public string TypemapOutputDirectory { get; set; }
+
+		[Required]
+		public bool GenerateNativeAssembly { get; set; }
+
 		public string ManifestTemplate { get; set; }
 		public string[] MergedManifestDocuments { get; set; }
 
@@ -71,6 +77,9 @@ public class GenerateJavaStubs : AndroidTask
 
 		public string ApplicationJavaClass { get; set; }
 
+		[Output]
+		public string [] GeneratedBinaryTypeMaps { get; set; }
+
 		internal const string AndroidSkipJavaStubGeneration = "AndroidSkipJavaStubGeneration";
 
 		public override bool RunTask ()
@@ -108,71 +117,97 @@ void Run (DirectoryAssemblyResolver res)
 			}
 
 			// Put every assembly we'll need in the resolver
+			bool hasExportReference = false;
+			bool haveMonoAndroid = false;
+			var allTypemapAssemblies = new HashSet<string> (StringComparer.OrdinalIgnoreCase);
+			var userAssemblies = new Dictionary<string, string> (StringComparer.OrdinalIgnoreCase);
 			foreach (var assembly in ResolvedAssemblies) {
-				if (bool.TryParse (assembly.GetMetadata (AndroidSkipJavaStubGeneration), out bool value) && value) {
+				bool value;
+				if (bool.TryParse (assembly.GetMetadata (AndroidSkipJavaStubGeneration), out value) && value) {
 					Log.LogDebugMessage ($"Skipping Java Stub Generation for {assembly.ItemSpec}");
 					continue;
 				}
+
+				bool addAssembly = false;
+				string fileName = Path.GetFileName (assembly.ItemSpec);
+				if (!hasExportReference && String.Compare ("Mono.Android.Export.dll", fileName, StringComparison.OrdinalIgnoreCase) == 0) {
+					hasExportReference = true;
+					addAssembly = true;
+				} else if (!haveMonoAndroid && String.Compare ("Mono.Android.dll", fileName, StringComparison.OrdinalIgnoreCase) == 0) {
+					haveMonoAndroid = true;
+					addAssembly = true;
+				} else if (MonoAndroidHelper.FrameworkAssembliesToTreatAsUserAssemblies.Contains (fileName)) {
+					if (!bool.TryParse (assembly.GetMetadata (AndroidSkipJavaStubGeneration), out value) || !value) {
+						string name = Path.GetFileNameWithoutExtension (fileName);
+						if (!userAssemblies.ContainsKey (name))
+							userAssemblies.Add (name, assembly.ItemSpec);
+						addAssembly = true;
+					}
+				}
+
+				if (addAssembly) {
+					if (!allTypemapAssemblies.Contains (assembly.ItemSpec))
+						allTypemapAssemblies.Add (assembly.ItemSpec);
+				}
+
 				res.Load (assembly.ItemSpec);
 			}
 
-			// However we only want to look for JLO types in user code
-			List<string> assemblies = new List<string> ();
+			// However we only want to look for JLO types in user code for Java stub code generation
 			foreach (var asm in ResolvedUserAssemblies) {
 				if (bool.TryParse (asm.GetMetadata (AndroidSkipJavaStubGeneration), out bool value) && value) {
 					Log.LogDebugMessage ($"Skipping Java Stub Generation for {asm.ItemSpec}");
 					continue;
 				}
-				if (!assemblies.All (x => Path.GetFileName (x) != Path.GetFileName (asm.ItemSpec)))
-					continue;
-				Log.LogDebugMessage ($"Adding {asm.ItemSpec} to assemblies.");
-				assemblies.Add (asm.ItemSpec);
-			}
-			foreach (var asm in MonoAndroidHelper.GetFrameworkAssembliesToTreatAsUserAssemblies (ResolvedAssemblies)) {
-				if (bool.TryParse (asm.GetMetadata (AndroidSkipJavaStubGeneration), out bool value) && value) {
-					Log.LogDebugMessage ($"Skipping Java Stub Generation for {asm.ItemSpec}");
-					continue;
-				}
-				if (!assemblies.All (x => Path.GetFileName (x) != Path.GetFileName (asm.ItemSpec)))
-					continue;
-				Log.LogDebugMessage ($"Adding {asm.ItemSpec} to assemblies.");
-				assemblies.Add (asm.ItemSpec);
+				if (!allTypemapAssemblies.Contains (asm.ItemSpec))
+					allTypemapAssemblies.Add (asm.ItemSpec);
+				userAssemblies.Add (Path.GetFileNameWithoutExtension (asm.ItemSpec), asm.ItemSpec);
 			}
 
 			// Step 1 - Find all the JLO types
 			var scanner = new JavaTypeScanner (this.CreateTaskLogger ()) {
 				ErrorOnCustomJavaObject     = ErrorOnCustomJavaObject,
 			};
-			var all_java_types = scanner.GetJavaTypes (assemblies, res);
 
-			var java_types = all_java_types
-				.Where (t => !JavaTypeScanner.ShouldSkipJavaCallableWrapperGeneration (t))
-				.ToArray ();
+			List<TypeDefinition> allJavaTypes = scanner.GetJavaTypes (allTypemapAssemblies, res);
 
-			// Step 2 - Generate Java stub code
+			// Step 2 - Generate type maps
+			//   Type mappings need to use all the assemblies, always.
+			WriteTypeMappings (res, allJavaTypes);
+
+			var javaTypes = new List<TypeDefinition> ();
+			foreach (TypeDefinition td in allJavaTypes) {
+				if (!userAssemblies.ContainsKey (td.Module.Assembly.Name.Name) || JavaTypeScanner.ShouldSkipJavaCallableWrapperGeneration (td)) {
+					continue;
+				}
+
+				javaTypes.Add (td);
+			}
+
+			// Step 3 - Generate Java stub code
 			var success = Generator.CreateJavaSources (
 				Log,
-				java_types,
+				javaTypes,
 				Path.Combine (OutputDirectory, "src"),
 				ApplicationJavaClass,
 				AndroidSdkPlatform,
 				UseSharedRuntime,
 				int.Parse (AndroidSdkPlatform) <= 10,
-				ResolvedAssemblies.Any (assembly => Path.GetFileName (assembly.ItemSpec) == "Mono.Android.Export.dll"));
+				hasExportReference);
 			if (!success)
 				return;
 
 			// We need to save a map of .NET type -> ACW type for resource file fixups
-			var managed = new Dictionary<string, TypeDefinition> (java_types.Length, StringComparer.Ordinal);
-			var java    = new Dictionary<string, TypeDefinition> (java_types.Length, StringComparer.Ordinal);
+			var managed = new Dictionary<string, TypeDefinition> (javaTypes.Count, StringComparer.Ordinal);
+			var java    = new Dictionary<string, TypeDefinition> (javaTypes.Count, StringComparer.Ordinal);
 
 			var managedConflicts = new Dictionary<string, List<string>> (0, StringComparer.Ordinal);
 			var javaConflicts    = new Dictionary<string, List<string>> (0, StringComparer.Ordinal);
 
 			// Allocate a MemoryStream with a reasonable guess at its capacity
-			using (var stream = new MemoryStream (java_types.Length * 32))
+			using (var stream = new MemoryStream (javaTypes.Count * 32))
 			using (var acw_map = new StreamWriter (stream)) {
-				foreach (var type in java_types) {
+				foreach (TypeDefinition type in javaTypes) {
 					string managedKey = type.FullName.Replace ('/', '.');
 					string javaKey = JavaNativeTypeManager.ToJniName (type).Replace ('/', '.');
 
@@ -237,7 +272,7 @@ void Run (DirectoryAssemblyResolver res)
 			manifest.PackageName = PackageName;
 			manifest.ApplicationName = ApplicationName ?? PackageName;
 			manifest.Placeholders = ManifestPlaceholders;
-			manifest.Assemblies.AddRange (assemblies);
+			manifest.Assemblies.AddRange (userAssemblies.Values);
 			manifest.Resolver = res;
 			manifest.SdkDir = AndroidSdkDir;
 			manifest.SdkVersion = AndroidSdkPlatform;
@@ -246,7 +281,7 @@ void Run (DirectoryAssemblyResolver res)
 			manifest.NeedsInternet = NeedsInternet;
 			manifest.InstantRunEnabled = InstantRunEnabled;
 
-			var additionalProviders = manifest.Merge (Log, all_java_types, ApplicationJavaClass, EmbedAssemblies, BundledWearApplicationName, MergedManifestDocuments);
+			var additionalProviders = manifest.Merge (Log, allJavaTypes, ApplicationJavaClass, EmbedAssemblies, BundledWearApplicationName, MergedManifestDocuments);
 
 			using (var stream = new MemoryStream ()) {
 				manifest.Save (Log, stream);
@@ -268,7 +303,7 @@ void Run (DirectoryAssemblyResolver res)
 			// Create additional application java sources.
 			StringWriter regCallsWriter = new StringWriter ();
 			regCallsWriter.WriteLine ("\t\t// Application and Instrumentation ACWs must be registered first.");
-			foreach (var type in java_types) {
+			foreach (var type in javaTypes) {
 				if (JavaNativeTypeManager.IsApplication (type) || JavaNativeTypeManager.IsInstrumentation (type)) {
 					string javaKey = JavaNativeTypeManager.ToJniName (type).Replace ('/', '.');				
 					regCallsWriter.WriteLine ("\t\tmono.android.Runtime.register (\"{0}\", {1}.class, {1}.__md_methods);",
@@ -296,5 +331,13 @@ void SaveResource (string resource, string filename, string destDir, Func<string
 			template = applyTemplate (template);
 			MonoAndroidHelper.CopyIfStringChanged (template, Path.Combine (destDir, filename));
 		}
+
+		void WriteTypeMappings (DirectoryAssemblyResolver resolver, List<TypeDefinition> types)
+		{
+			var tmg = new TypeMapGenerator ((string message) => Log.LogDebugMessage (message), SupportedAbis);
+			if (!tmg.Generate (types, TypemapOutputDirectory, GenerateNativeAssembly))
+				throw new XamarinAndroidException (99999, "Failed to generate type maps");
+			GeneratedBinaryTypeMaps = tmg.GeneratedBinaryTypeMaps.ToArray ();
+		}
 	}
 }

src/Xamarin.Android.Build.Tasks/Tasks/GenerateTypeMaps.cs

@@ -307,7 +307,7 @@ public static bool IsFrameworkAssembly (string assembly, bool checkSdkPath)
 		{
 			if (IsSharedRuntimeAssembly (assembly)) {
 #if MSBUILD
-				bool treatAsUser = Array.BinarySearch (FrameworkAssembliesToTreatAsUserAssemblies, Path.GetFileName (assembly), StringComparer.OrdinalIgnoreCase) >= 0;
+				bool treatAsUser = FrameworkAssembliesToTreatAsUserAssemblies.Contains (Path.GetFileName (assembly));
 				// Framework assemblies don't come from outside the SDK Path;
 				// user assemblies do
 				if (checkSdkPath && treatAsUser && TargetFrameworkDirectories != null) {
@@ -527,10 +527,14 @@ public static bool IsRawResourcePath (string projectPath)
 
 #if MSBUILD
 		internal static IEnumerable<ITaskItem> GetFrameworkAssembliesToTreatAsUserAssemblies (ITaskItem[] resolvedAssemblies) 
-		{		
-			return resolvedAssemblies
-				.Where (f => Array.BinarySearch (FrameworkAssembliesToTreatAsUserAssemblies, Path.GetFileName (f.ItemSpec), StringComparer.OrdinalIgnoreCase) >= 0)
-				.Select(p => p);
+		{
+			var ret = new List<ITaskItem> ();
+			foreach (ITaskItem item in resolvedAssemblies) {
+				if (FrameworkAssembliesToTreatAsUserAssemblies.Contains (Path.GetFileName (item.ItemSpec)))
+					ret.Add (item);
+			}
+
+			return ret;
 		}
 #endif
 
@@ -544,7 +548,7 @@ internal static IEnumerable<ITaskItem> GetFrameworkAssembliesToTreatAsUserAssemb
 			"Mono.Posix.dll",
 		};
 		// MUST BE SORTED CASE-INSENSITIVE
-		internal static readonly string[] FrameworkAssembliesToTreatAsUserAssemblies = {
+		internal static readonly HashSet<string> FrameworkAssembliesToTreatAsUserAssemblies = new HashSet<string> (StringComparer.OrdinalIgnoreCase) {
 			"Mono.Android.Support.v13.dll",
 			"Mono.Android.Support.v4.dll",
 			"Xamarin.Android.NUnitLite.dll",

src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs

@@ -80,36 +80,21 @@ public TypeMapGenerator (Action<string> logger, string[] supportedAbis)
 			this.logger = logger ?? throw new ArgumentNullException (nameof (logger));
 			if (supportedAbis == null)
 				throw new ArgumentNullException (nameof (supportedAbis));
-			if (supportedAbis.Length == 0)
-				throw new ArgumentException ("must not be empty", nameof (supportedAbis));
 			this.supportedAbis = supportedAbis;
 
 			outputEncoding = new UTF8Encoding (false);
 			moduleMagicString = outputEncoding.GetBytes (TypeMapMagicString);
 			typemapIndexMagicString = outputEncoding.GetBytes (TypeMapIndexMagicString);
 		}
 
-		void LoggerShim (TraceLevel level, string message)
+		public bool Generate (List<TypeDefinition> javaTypes, string outputDirectory, bool generateNativeAssembly)
 		{
-			logger (message);
-		}
-
-		public bool Generate (DirectoryAssemblyResolver resolver, IEnumerable<string> assemblies, string outputDirectory, bool generateNativeAssembly)
-		{
-			if (assemblies == null)
-				throw new ArgumentNullException (nameof (assemblies));
 			if (String.IsNullOrEmpty (outputDirectory))
 				throw new ArgumentException ("must not be null or empty", nameof (outputDirectory));
 
 			if (!Directory.Exists (outputDirectory))
 				Directory.CreateDirectory (outputDirectory);
 
-			var scanner = new JavaTypeScanner (LoggerShim) {
-				ErrorOnCustomJavaObject = false
-			};
-
-			List<TypeDefinition> javaTypes = scanner.GetJavaTypes (assemblies, resolver);
-
 			int assemblyId = 0;
 			int maxJavaNameLength = 0;
 			int maxModuleFileNameLength = 0;