[Xamarin.Android.Tools.ApiXmlAdjuster] Use Dictionaries for perf (#756)

The `Xamarin.Android.Tools.ApiXmlAdjuster` process builds an in-memory
model of every Java type we know about, and then queries this model
many times in order to ensure we can resolve every needed Java type to
build a binding. The data structure of this model is:
public class JavaApi
{
public List<JavaPackage> Packages { get; }
}
public class JavaPackage
{
public List<JavaType> Types { get; }
}
The model is then queried using LINQ::
// Bad
var type = api.Packages.SelectMany (p => p.Types)
.FirstOrDefault (t => t.Name == type_name);
// Less bad
var type = api.Packages.FirstOrDefault (p => p.Name == pkg_name)
?.Types.FirstOrDefault (t => t.Name == type_name);
In the random GooglePlayServices package I used for testing, `JavaApi`
contained 310 packages and a total of 5941 types. Repeatedly looping
through them looking for the correct type takes a considerable amount
of time.
Instead, we can use a `Dictionary` to store packages and types keyed by
name to significantly speed up type resolution:
public class JavaApi
{
public Dictionary<string, JavaPackage> Packages { get; }
}
public class JavaPackage
{
public Dictionary<string, List<JavaType>> Types { get; }
}
For the GPS project, this reduced time taken considerably:
| Version | Time |
| ------- | ---- |
| master | 9.3s |
| This PR | 1.4s |
The only "interesting" detail is that we can have multiple types with
the same *Java* name, such as `MyInterface` and `MyInterfaceConsts`.
Thus we need to use `Dictionary<string, List<JavaType>>` to ensure we
collect them all.

Author: jpobst

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

@@ -315,7 +315,12 @@ public JavaStubGrammar ()
 identifier.AstConfig.NodeCreator=(ctx,node)=>node.AstNode=node.Token.ValueString;
 compile_unit.AstConfig.NodeCreator=(ctx,node)=>{
 ProcessChildren(ctx,node);
-node.AstNode=newJavaPackage(null){Name=(string)node.ChildNodes[0].AstNode,Types=((IEnumerable<JavaType>)node.ChildNodes[2].AstNode).ToList()};
+varpkg=newJavaPackage(null){Name=(string)node.ChildNodes[0].AstNode};
+
+foreach(vartin(IEnumerable<JavaType>)node.ChildNodes[2].AstNode)
+pkg.AddType(t);
+
+node.AstNode=pkg;
 };
 opt_package_decl.AstConfig.NodeCreator=SelectSingleChild;
 package_decl.AstConfig.NodeCreator=SelectChildValueAt(1);
@@ -637,9 +642,13 @@ public JavaStubParser ()
 voidFlattenNestedTypes(JavaPackagepackage)
 {
 varresults=newList<JavaType>();
-foreach(vartinpackage.Types)
+foreach(vartinpackage.AllTypes)
 Flatten(results,t);
-package.Types=results.ToList();
+
+package.ClearTypes();
+
+foreach(vartinresults)
+package.AddType(t);
 
 voidFlatten(List<JavaType>list,JavaTypet)
 {

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

@@ -10,29 +10,77 @@ public partial class JavaApi
 {
 publicJavaApi()
 {
-Packages=newList<JavaPackage>();
+Packages=newDictionary<string,JavaPackage>();
 }
 
 publicstring?ExtendedApiSource{get;set;}
 publicstring?Platform{get;set;}
-publicIList<JavaPackage>Packages{get;set;}
+publicIDictionary<string,JavaPackage>Packages{get;}
+
+publicICollection<JavaPackage>AllPackages=>Packages.Values;
 }
 
 publicpartialclassJavaPackage
 {
+privateDictionary<string,List<JavaType>>types=newDictionary<string,List<JavaType>>();
+
 publicJavaPackage(JavaApi?parent)
 {
 Parent=parent;
-
-Types=newList<JavaType>();
 }
 
 publicJavaApi?Parent{get;privateset;}
 
 publicstring?Name{get;set;}
 publicstring?JniName{get;set;}
-publicIList<JavaType>Types{get;set;}
-
+
+// Yes, there can be multiple types with the same *Java* name.
+// For example:
+// - MyInterface
+// - MyInterfaceConsts
+// It's debatable whether we handle this "properly", as most callers just
+// do `First ()`, but it's been working for years so I'm not changing it.
+// Exposes an IReadOnlyDictionary so caller cannot bypass our AddType/RemoveType code.
+publicIReadOnlyDictionary<string,List<JavaType>>Types=>types;
+
+// Use this for a flat list of *all* types
+publicIEnumerable<JavaType>AllTypes=>Types.Values.SelectMany(v =>v);
+
+publicvoidAddType(JavaTypetype)
+{
+// If this is a duplicate key, add it to existing list
+if(Types.TryGetValue(type.Name!,outvarlist)){
+list.Add(type);
+return;
+}
+
+// Add to a new list
+varnew_list=newList<JavaType>();
+new_list.Add(type);
+
+types.Add(type.Name!,new_list);
+}
+
+publicvoidRemoveType(JavaTypetype)
+{
+if(!Types.TryGetValue(type.Name!,outvarlist))
+return;
+
+// Remove 1 type from list if it contains multiple types
+if(list.Count>1){
+list.Remove(type);
+return;
+}
+
+// Remove the whole dictionary entry
+types.Remove(type.Name!);
+}
+
+publicvoidClearTypes()
+{
+types.Clear();
+}
+
 // Content of this value is not stable.
 publicoverridestringToString()
 {
@@ -123,14 +171,14 @@ static ManagedType ()
 dummy_system_package=newJavaPackage(null){Name="System"};
 system_object=newManagedType(dummy_system_package){Name="Object"};
 system_exception=newManagedType(dummy_system_package){Name="Exception"};
-dummy_system_package.Types.Add(system_object);
-dummy_system_package.Types.Add(system_exception);
+dummy_system_package.AddType(system_object);
+dummy_system_package.AddType(system_exception);
 dummy_system_io_package=newJavaPackage(null){Name="System.IO"};
 system_io_stream=newManagedType(dummy_system_io_package){Name="Stream"};
-dummy_system_io_package.Types.Add(system_io_stream);
+dummy_system_io_package.AddType(system_io_stream);
 dummy_system_xml_package=newJavaPackage(null){Name="System.Xml"};
 system_xml_xmlreader=newManagedType(dummy_system_xml_package){Name="XmlReader"};
-dummy_system_io_package.Types.Add(system_xml_xmlreader);
+dummy_system_io_package.AddType(system_xml_xmlreader);
 }
 
 publicstaticIEnumerable<JavaPackage>DummyManagedPackages{

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiDefectFinderExtensions.cs

@@ -7,7 +7,7 @@ public static class JavaApiDefectFinderExtensions
 {
 publicstaticvoidFindDefects(thisJavaApiapi)
 {
-foreach(vartypeinapi.Packages.SelectMany(p =>p.Types).Where(t =>!t.IsReferenceOnly))
+foreach(vartypeinapi.AllPackages.SelectMany(p =>p.AllTypes).Where(t =>!t.IsReferenceOnly))
 type.FindDefects();
 }
 

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiGenericInheritanceMapperExtensions.cs

@@ -8,7 +8,7 @@ public static class JavaApiGenericInheritanceMapperExtensions
 {
 publicstaticvoidCreateGenericInheritanceMapping(thisJavaApiapi)
 {
-foreach(varklsinapi.Packages.SelectMany(p =>p.Types).OfType<JavaClass>())
+foreach(varklsinapi.AllPackages.SelectMany(p =>p.AllTypes).OfType<JavaClass>())
 kls.PrepareGenericInheritanceMapping();
 }
 

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiNonBindableStripper.cs

@@ -9,7 +9,7 @@ public static class JavaApiNonBindableStripper
 publicstaticvoidStripNonBindables(thisJavaApiapi)
 {
 varinvalids=newList<JavaMember>();
-foreach(varmemberinapi.Packages.SelectMany(p =>p.Types)
+foreach(varmemberinapi.AllPackages.SelectMany(p =>p.AllTypes)
 .SelectMany(t =>t.Members).Where(m =>m.Name!=null&&m.Name.Contains('$')))
 invalids.Add(member);
 foreach(varinvalidininvalids)

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiOverrideMarkerExtensions.cs

@@ -14,7 +14,7 @@ public static void MarkOverrides (this JavaApi api)
 
 publicstaticvoidMarkOverrides(thisJavaApiapi,HashSet<JavaClass>doneList)
 {
-foreach(varklsinapi.Packages.SelectMany(p =>p.Types).OfType<JavaClass>())
+foreach(varklsinapi.AllPackages.SelectMany(p =>p.AllTypes).OfType<JavaClass>())
 kls.MarkOverrides(doneList);
 }
 

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiTypeResolverExtensions.cs

@@ -39,13 +39,31 @@ static JavaTypeReference JavaTypeNameToReference (this JavaApi api, JavaTypeName
 
 publicstaticJavaTypeFindNonGenericType(thisJavaApiapi,string?name)
 {
-varret=FindPackages(api,name??"")
-.SelectMany(p =>p.Types)
-.FirstOrDefault(t =>name==(t.Parent?.Name!=null?t.Parent.Name+".":"")+t.Name);
-if(ret==null)
-ret=ManagedType.DummyManagedPackages
-.SelectMany(p =>p.Types)
-.FirstOrDefault(t =>t.FullName==name);
+// Given a type name like 'android.graphics.BitmapFactory.Options'
+// We're going to search for:
+// - Pkg: android.graphics.BitmapFactory Type: Options
+// - Pkg: android.graphics Type: BitmapFactory.Options
+// - Pkg: android Type: graphics.BitmapFactory.Options
+// etc. We will short-circuit as soon as we find a match
+varindex=name?.LastIndexOf('.')??-1;
+
+while(index>0){
+varns=name!.Substring(0,index);
+vartype_name=name.Substring(index+1);
+
+if(api.Packages.TryGetValue(ns,outvarpkg)){
+if(pkg.Types.TryGetValue(type_name,outvartype))
+returntype.First();
+}
+
+index=name.LastIndexOf('.',index-1);
+}
+
+// See if it's purely a C# type
+varret=ManagedType.DummyManagedPackages
+.SelectMany(p =>p.AllTypes)
+.FirstOrDefault(t =>t.FullName==name);
+
 if(ret==null){
 // We moved this type to "mono.android.app.IntentService" which makes this
 // type resolution fail if a user tries to reference it in Java.
@@ -58,43 +76,26 @@ public static JavaType FindNonGenericType (this JavaApi api, string? name)
 returnret;
 }
 
-staticIEnumerable<JavaPackage>FindPackages(JavaApiapi,stringname)
-{
-// Given a type name like "java.lang.Object", return packages that could
-// possibly contain the type so we don't search all packages, ie:
-// - java.lang
-// - java
-varpackage_names=newList<string>();
-intindex;
-
-while((index=name.LastIndexOf('.'))>=0){
-name=name.Substring(0,index);
-package_names.Add(name);
-}
-
-returnapi.Packages.Where(p =>package_names.Contains(p.Name,StringComparer.Ordinal)).ToList();
-}
-
 publicstaticvoidResolve(thisJavaApiapi)
 {
 while(true){
 boolerrors=false;
-foreach(vartinapi.Packages.SelectMany(p =>p.Types).OfType<JavaClass>().ToArray())
+foreach(vartinapi.AllPackages.SelectMany(p =>p.AllTypes).OfType<JavaClass>().ToArray())
 try{
 t.Resolve();
 }
 catch(JavaTypeResolutionExceptionex){
 Log.LogError("Error while processing type '{0}': {1}",t,ex.Message);
 errors=true;
-t.Parent?.Types.Remove(t);
+t.Parent?.RemoveType(t);
 }
-foreach(vartinapi.Packages.SelectMany(p =>p.Types).OfType<JavaInterface>().ToArray())
+foreach(vartinapi.AllPackages.SelectMany(p =>p.AllTypes).OfType<JavaInterface>().ToArray())
 try{
 t.Resolve();
 }catch(JavaTypeResolutionExceptionex){
 Log.LogError("Error while processing type '{0}': {1}",t,ex.Message);
 errors=true;
-t.Parent?.Types.Remove(t);
+t.Parent?.RemoveType(t);
 }
 if(!errors)
 break;

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiXmlGeneratorExtensions.cs

@@ -24,15 +24,15 @@ public static void Save (this JavaApi api, XmlWriter writer)
 if(api.Platform!=null)
 writer.WriteAttributeString("platform",api.Platform);
 
-foreach(varpkginapi.Packages){
-if(!pkg.Types.Any(t =>!t.IsReferenceOnly))
+foreach(varpkginapi.AllPackages){
+if(!pkg.AllTypes.Any(t =>!t.IsReferenceOnly))
 continue;
 writer.WriteStartElement("package");
 writer.WriteAttributeString("name",pkg.Name);
 if(!string.IsNullOrEmpty(pkg.JniName)){
 writer.WriteAttributeString("jni-name",pkg.JniName);
 }
-foreach(vartypeinpkg.Types){
+foreach(vartypeinpkg.AllTypes){
 if(type.IsReferenceOnly)
 continue;// skip reference only types
 if(typeisJavaClass)

src/Xamarin.Android.Tools.ApiXmlAdjuster/JavaApiXmlLoaderExtensions.cs

@@ -32,11 +32,14 @@ public static void Load (this JavaApi api, XmlReader reader, bool isReferenceOnl
 break;// </api>
 if(reader.NodeType!=XmlNodeType.Element||reader.LocalName!="package")
 throwXmlUtil.UnexpectedElementOrContent("api",reader,"package");
-varpkg=api.Packages.FirstOrDefault(p =>p.Name==reader.GetAttribute("name"));
-if(pkg==null){
+
+varname=reader.GetAttribute("name");
+
+if(!api.Packages.TryGetValue(name,outvarpkg)){
 pkg=newJavaPackage(api);
-api.Packages.Add(pkg);
+api.Packages.Add(name,pkg);
 }
+
 pkg.Load(reader,isReferenceOnly);
 }while(true);
 
@@ -67,11 +70,11 @@ public static void Load (this JavaPackage package, XmlReader reader, bool isRefe
 if(reader.LocalName=="class"){
 varkls=newJavaClass(package){IsReferenceOnly=isReferenceOnly};
 kls.Load(reader);
-package.Types.Add(kls);
+package.AddType(kls);
 }elseif(reader.LocalName=="interface"){
 variface=newJavaInterface(package){IsReferenceOnly=isReferenceOnly};
 iface.Load(reader);
-package.Types.Add(iface);
+package.AddType(iface);
 }else
 throwXmlUtil.UnexpectedElementOrContent("package",reader,"class","interface");
 }while(true);

tests/Java.Interop.Tools.JavaSource-Tests/JavaStubParserTests.cs

@@ -35,7 +35,7 @@ public static void m (String text) {
 Assert.AreEqual(null,package.Name);
 Assert.AreEqual(1,package.Types.Count);
 
-varExample_Type=package.Types[0];
+varExample_Type=package.AllTypes.First();
 Assert.AreEqual("Example",Example_Type.FullName);
 
 Assert.AreEqual(1,Example_Type.Members.Count);