Where's the documentation for FastProxy?

[AnsisMalins]

I could use some examples of basic usage.

In particular, what counts as a fast object? In my custom solution in ClearScript 7.4, I had objects implement an interface, and V8SplitProxyManaged would check for that interface and take the fast path if found. In ClearScript 7.5, I see IV8FastHostObject and IV8FastHostObjectOperations. Which of my C# objects should implement which interface for ClearScript to take the fast path with them?

[ClearScriptLib]

Hi @AnsisMalins,

I could use some examples of basic usage.

Sorry about that. We haven't had a chance to put a FastProxy tutorial together.

In particular, what counts as a fast object?

A fast host object is simply one that implements IV8FastHostObject. You could implement that interface yourself, but the API provides several helpers to simplify things while retaining flexibility.

Here's a basic example. Consider this class:

public class Foo { public long Value { get; set; } public double GetScaledValue(double scaleFactor) => Value * scaleFactor; }

Here's a version of the same class with FastProxy support:

public class FastFoo : V8FastHostObject<FastFoo> { public long Value { get; set; } public double GetScaledValue(double scaleFactor) => Value * scaleFactor; static FastFoo() { Configure(static configuration => { configuration.AddPropertyAccessors( nameof(Value), static (FastFoo self, in V8FastResult value) => value.Set(self.Value), static (FastFoo self, in V8FastArg value) => self.Value = value.GetInt64() ); configuration.AddMethodGetter( nameof(GetScaledValue), static (FastFoo self, in V8FastArgs args, in V8FastResult result) => result.Set(self.GetScaledValue(args.GetDouble(0))) ); }); } }

Note the differences – derivation from the V8FastHostObject<TObject> base and a static constructor to set up a FastProxy configuration for the class. That's sufficient for a typical class with a fixed set of members, but many other patterns are possible.

Here's a test program that uses Foo and FastFoo to demonstrate the FastProxy performance improvement:

using var engine = new V8ScriptEngine(); engine.AddHostType(typeof(Console)); engine.Script.foo = new Foo(); engine.Script.fastFoo = new FastFoo(); engine.Script.stopWatch = new Stopwatch(); engine.Execute(@"  const iterations = 1000000;  const scaleFactor = 1.0000123;  function test(name, foo) {  stopWatch.Restart();  for (let i = 0; i < iterations; ++i) {  foo.Value += i & 1 ? i : -i;  foo.Value = Math.round(foo.GetScaledValue(scaleFactor));  }  stopWatch.Stop();  Console.WriteLine('{0}: final value = {1}; elapsed time = {2} ms', name, foo.Value, stopWatch.ElapsedMilliseconds);  }  test('normal', foo);  test(' fast', fastFoo); ");

On our test machine, this program produces the following sample output:

normal: final value = 1449622482; elapsed time = 10588 ms fast: final value = 1449622482; elapsed time = 1577 ms 

Please let us know if you have additional questions about the FastProxy API.

Good luck!