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[JavaCallableWrappers] avoid string.Format() (#1061)
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Running PerfView on Windows in a .NET MAUI app, I can see this taking
up time inside the `<GenerateJavaStubs/>` MSBuild task:

| Name                                                                                                                  | Inc % |   Inc |
| --------------------------------------------------------------------------------------------------------------------- | ----: | ----: |
| java.interop.tools.javacallablewrappers!Java.Interop.Tools.JavaCallableWrappers.JavaCallableWrapperGenerator..ctor()  |   1.4 |    51 |
| mscorlib.ni!String.Format                                                                                             |   1.0 |    35 |

Around ~26ms appears to be spent inside
`JavaCallableWrapperGenerator` calling `string.Format()`.

Reviewing the code, there is quite a bit of `WriteLine()` used along
with format arguments.  I could rework this to use string
interpolation, which would be slightly better, as the C# compiler
could replace many of these with `string.Concat()`.

However, the best case is to just call `Write()` with individual
strings, so we don't do extra work creating intermediate string
values.

Copying `Java.Interop.Tools.JavaCallableWrappers.dll` to:

	C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\33.0.4\tools

It appears to save about ~17ms in a `dotnet new maui` project:

	Top 10 most expensive tasks
	--GenerateJavaStubs = 795 ms
	++GenerateJavaStubs = 812 ms

This was an incremental build with a `.xaml` change.
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@jonathanpeppers
jonathanpeppers authored Dec 6, 2022
1 parent 3a9f770 commit 09f8da2
Showing 1 changed file with 113 additions and 28 deletions.
141 changes: 113 additions & 28 deletions ...aCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaCallableWrapperGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -561,7 +561,9 @@ public void Generate (TextWriter writer)
continue;
}
needCtor = true;
writer.WriteLine ("\tstatic final String __md_{0}_methods;", i + 1);
writer.Write ("\tstatic final String __md_");
writer.Write (i + 1);
writer.WriteLine ("_methods;");
}
}

Expand All @@ -574,8 +576,7 @@ public void Generate (TextWriter writer)

if (children != null) {
for (int i = 0; i < children.Count; ++i) {
string methods = string.Format ("__md_{0}_methods", i + 1);
GenerateRegisterType (writer, children [i], methods);
GenerateRegisterType (writer, children [i], $"__md_{i + 1}_methods");
}
}
writer.WriteLine ("\t}");
Expand Down Expand Up @@ -613,7 +614,9 @@ static void WriteAnnotations (string indent, TextWriter sw, IEnumerable<CustomAt
var catype = ca.AttributeType.Resolve ();
var tca = catype.CustomAttributes.FirstOrDefault (a => a.AttributeType.FullName == "Android.Runtime.AnnotationAttribute");
if (tca != null) {
sw.Write ("{0}@{1}", indent, tca.ConstructorArguments [0].Value);
sw.Write (indent);
sw.Write ('@');
sw.Write (tca.ConstructorArguments [0].Value);
if (ca.Properties.Count > 0) {
sw.WriteLine ("(");
bool wrote = false;
Expand All @@ -622,7 +625,9 @@ static void WriteAnnotations (string indent, TextWriter sw, IEnumerable<CustomAt
sw.WriteLine (',');
var pd = catype.Properties.FirstOrDefault (pp => pp.Name == p.Name);
var reg = pd != null ? pd.CustomAttributes.FirstOrDefault (pdca => pdca.AttributeType.FullName == "Android.Runtime.RegisterAttribute") : null;
sw.Write ("{0} = {1}", reg != null ? reg.ConstructorArguments [0].Value : p.Name, ManagedValueToJavaSource (p.Argument.Value));
sw.Write (reg != null ? reg.ConstructorArguments [0].Value : p.Name);
sw.Write (" = ");
sw.Write (ManagedValueToJavaSource (p.Argument.Value));
wrote = true;
}
sw.Write (")");
Expand Down Expand Up @@ -674,7 +679,8 @@ void GenerateHeader (TextWriter sw)
if (ifaces.Any ()) {
foreach (TypeDefinition iface in ifaces) {
sw.WriteLine (",");
sw.Write ("\t\t{0}", GetJavaTypeName (iface, cache));
sw.Write ("\t\t");
sw.Write (GetJavaTypeName (iface, cache));
}
}
sw.WriteLine ();
Expand All @@ -699,12 +705,20 @@ void GenerateBody (TextWriter sw)

if (GenerateOnCreateOverrides && JavaNativeTypeManager.IsApplication (type, cache) && !methods.Any (m => m.Name == "onCreate"))
WriteApplicationOnCreate (sw, w => {
w.WriteLine ("\t\tmono.android.Runtime.register (\"{0}\", {1}.class, __md_methods);", type.GetPartialAssemblyQualifiedName (cache), name);
w.Write ("\t\tmono.android.Runtime.register (\"");
w.Write (type.GetPartialAssemblyQualifiedName (cache));
w.Write ("\", ");
w.Write (name);
w.WriteLine (".class, __md_methods);");
w.WriteLine ("\t\tsuper.onCreate ();");
});
if (GenerateOnCreateOverrides && JavaNativeTypeManager.IsInstrumentation (type, cache) && !methods.Any (m => m.Name == "onCreate"))
WriteInstrumentationOnCreate (sw, w => {
w.WriteLine ("\t\tmono.android.Runtime.register (\"{0}\", {1}.class, __md_methods);", type.GetPartialAssemblyQualifiedName (cache), name);
w.Write ("\t\tmono.android.Runtime.register (\"");
w.Write (type.GetPartialAssemblyQualifiedName (cache));
w.Write ("\", ");
w.Write (name);
w.WriteLine (".class, __md_methods);");
w.WriteLine ("\t\tsuper.onCreate (arguments);");
});

Expand Down Expand Up @@ -737,29 +751,43 @@ void GenerateRegisterType (TextWriter sw, JavaCallableWrapperGenerator self, str
return;
}

sw.WriteLine ("\t\t{0} = ", field);
sw.Write ("\t\t");
sw.Write (field);
sw.WriteLine (" = ");
string managedTypeName = self.type.GetPartialAssemblyQualifiedName (cache);
string javaTypeName = $"{package}.{name}";

foreach (Signature method in self.methods) {
if (method.IsDynamicallyRegistered) {
sw.WriteLine ("\t\t\t\"{0}\\n\" +", method.Method);
sw.Write ("\t\t\t\"", method.Method);
sw.Write (method.Method);
sw.WriteLine ("\\n\" +");
}
}
sw.WriteLine ("\t\t\t\"\";");
if (CannotRegisterInStaticConstructor (self.type))
return;
string? format = null;
sw.Write ("\t\t");
switch (CodeGenerationTarget) {
case JavaPeerStyle.JavaInterop1:
format = "com.xamarin.java_interop.ManagedPeer.registerNativeMembers ({1}.class, \"{0}\", {2});";
sw.Write ("com.xamarin.java_interop.ManagedPeer.registerNativeMembers (");
sw.Write (self.name);
sw.Write (".class, \"");
sw.Write (managedTypeName);
sw.Write ("\", ");
sw.Write (field);
sw.WriteLine (");");
break;
default:
format = "mono.android.Runtime.register (\"{0}\", {1}.class, {2});";
sw.Write ("mono.android.Runtime.register (\"");
sw.Write (managedTypeName);
sw.Write ("\", ");
sw.Write (self.name);
sw.Write (".class, ");
sw.Write (field);
sw.WriteLine (");");
break;
}
sw.Write ("\t\t");
sw.WriteLine (format, managedTypeName, self.name, field);
}

void GenerateFooter (TextWriter sw)
Expand Down Expand Up @@ -922,25 +950,44 @@ void GenerateConstructor (Signature ctor, TextWriter sw)
sw.WriteLine ();
if (ctor.Annotations != null)
sw.WriteLine (ctor.Annotations);
sw.WriteLine ("\tpublic {0} ({1}){2}", name, ctor.Params, ctor.ThrowsDeclaration);
sw.Write ("\tpublic ");
sw.Write (name);
sw.Write (" (");
sw.Write (ctor.Params);
sw.Write (')');
sw.WriteLine (ctor.ThrowsDeclaration);
sw.WriteLine ("\t{");
sw.WriteLine ("\t\tsuper ({0});", ctor.SuperCall);
sw.Write ("\t\tsuper (");
sw.Write (ctor.SuperCall);
sw.WriteLine (");");
#if MONODROID_TIMING
sw.WriteLine ("\t\tandroid.util.Log.i(\"MonoDroid-Timing\", \"{0}..ctor({1}): time: \"+java.lang.System.currentTimeMillis());", name, ctor.Params);
#endif
if (!CannotRegisterInStaticConstructor (type)) {
string? format = null;
sw.Write ("\t\tif (getClass () == ");
sw.Write (name);
sw.WriteLine (".class) {");
sw.Write ("\t\t\t");
switch (CodeGenerationTarget) {
case JavaPeerStyle.JavaInterop1:
format = "com.xamarin.java_interop.ManagedPeer.construct (this, \"{0}\", \"{1}\", new java.lang.Object[] {{ {2} }});";
sw.Write ("com.xamarin.java_interop.ManagedPeer.construct (this, \"");
sw.Write (type.GetPartialAssemblyQualifiedName (cache));
sw.Write ("\", \"");
sw.Write (ctor.ManagedParameters);
sw.Write ("\", new java.lang.Object[] { ");
sw.Write (ctor.ActivateCall);
sw.WriteLine (" });");
break;
default:
format = "mono.android.TypeManager.Activate (\"{0}\", \"{1}\", this, new java.lang.Object[] {{ {2} }});";
sw.Write ("mono.android.TypeManager.Activate (\"");
sw.Write (type.GetPartialAssemblyQualifiedName (cache));
sw.Write ("\", \"");
sw.Write (ctor.ManagedParameters);
sw.Write ("\", this, new java.lang.Object[] { ");
sw.Write (ctor.ActivateCall);
sw.WriteLine (" });");
break;
}
sw.WriteLine ("\t\tif (getClass () == {0}.class) {{", name);
sw.Write ("\t\t\t");
sw.WriteLine (format, type.GetPartialAssemblyQualifiedName (cache), ctor.ManagedParameters, ctor.ActivateCall);
sw.WriteLine ("\t\t}");
}
sw.WriteLine ("\t}");
Expand All @@ -953,7 +1000,9 @@ void GenerateApplicationConstructor (TextWriter sw)
}

sw.WriteLine ();
sw.WriteLine ("\tpublic {0} ()", name);
sw.Write ("\tpublic ");
sw.Write (name);
sw.WriteLine (" ()");
sw.WriteLine ("\t{");
sw.WriteLine ("\t\tmono.MonoPackageManager.setContext (this);");
sw.WriteLine ("\t}");
Expand All @@ -964,24 +1013,60 @@ void GenerateExportedField (JavaFieldInfo field, TextWriter sw)
sw.WriteLine ();
if (field.Annotations != null)
sw.WriteLine (field.Annotations);
sw.WriteLine ("\t{0} {1}{2} {3} = {4} ();", field.GetJavaAccess (), field.IsStatic ? "static " : null, field.TypeName, field.FieldName, field.InitializerName);
sw.Write ("\t");
sw.Write (field.GetJavaAccess ());
sw.Write (' ');
if (field.IsStatic)
sw.Write ("static ");
sw.Write (field.TypeName);
sw.Write (' ');
sw.Write (field.FieldName);
sw.Write (" = ");
sw.Write (field.InitializerName);
sw.WriteLine (" ();");
}

void GenerateMethod (Signature method, TextWriter sw)
{
sw.WriteLine ();
if (method.Annotations != null)
sw.WriteLine (method.Annotations);
sw.WriteLine ("\t{0} {1}{2} {3} ({4}){5}", method.IsExport ? method.JavaAccess : "public", method.IsStatic ? "static " : null, method.Retval, method.JavaName, method.Params, method.ThrowsDeclaration);
sw.Write ("\t");
sw.Write (method.IsExport ? method.JavaAccess : "public");
sw.Write (' ');
if (method.IsStatic)
sw.Write ("static ");
sw.Write (method.Retval);
sw.Write (' ');
sw.Write (method.JavaName);
sw.Write (" (");
sw.Write (method.Params);
sw.Write (')');
sw.WriteLine (method.ThrowsDeclaration);
sw.WriteLine ("\t{");
#if MONODROID_TIMING
sw.WriteLine ("\t\tandroid.util.Log.i(\"MonoDroid-Timing\", \"{0}.{1}: time: \"+java.lang.System.currentTimeMillis());", name, method.Name);
#endif
sw.WriteLine ("\t\t{0}n_{1} ({2});", method.Retval == "void" ? String.Empty : "return ", method.Name, method.ActivateCall);
sw.Write ("\t\t");
sw.Write (method.Retval == "void" ? String.Empty : "return ");
sw.Write ("n_");
sw.Write (method.Name);
sw.Write (" (");
sw.Write (method.ActivateCall);
sw.WriteLine (");");

sw.WriteLine ("\t}");
sw.WriteLine ();
sw.WriteLine ("\tprivate {0}native {1} n_{2} ({3});", method.IsStatic ? "static " : null, method.Retval, method.Name, method.Params);
sw.Write ("\tprivate ");
if (method.IsStatic)
sw.Write ("static ");
sw.Write ("native ");
sw.Write (method.Retval);
sw.Write (" n_");
sw.Write (method.Name);
sw.Write (" (");
sw.Write (method.Params);
sw.WriteLine (");");
}

void WriteApplicationOnCreate (TextWriter sw, Action<TextWriter> extra)
Expand Down

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