Separate torchbind from Python (#30242)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30242

Pull Request resolved: https://github.com/pytorch/pytorch/pull/29501

Currently blocked on schema serialization issue

Test Plan: Imported from OSS

Differential Revision: D18463063

Pulled By: jamesr66a

fbshipit-source-id: c12a1b644eb9bf04e68ff93cccf91d6cb3e75359

test/cpp/jit/test_custom_class.cpp

@@ -0,0 +1,66 @@
+#include <torch/custom_class.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+namespace torch {
+namespace jit {
+
+namespace {
+
+struct Foo : torch::jit::CustomClassHolder {
+  int x, y;
+  Foo() : x(0), y(0) {}
+  Foo(int x_, int y_) : x(x_), y(y_) {}
+  int64_t info() {
+    return this->x * this->y;
+  }
+  int64_t add(int64_t z) {
+    return (x + y) * z;
+  }
+  void increment(int64_t z) {
+    this->x += z;
+    this->y += z;
+  }
+  int64_t combine(c10::intrusive_ptr<Foo> b) {
+    return this->info() + b->info();
+  }
+  ~Foo() {
+    // std::cout<<"Destroying object with values: "<<x<<' '<<y<<std::endl;
+  }
+};
+
+template <class T>
+struct Stack : torch::jit::CustomClassHolder {
+  std::vector<T> stack_;
+  Stack(std::vector<T> init) : stack_(init.begin(), init.end()) {}
+
+  void push(T x) {
+    stack_.push_back(x);
+  }
+  T pop() {
+    auto val = stack_.back();
+    stack_.pop_back();
+    return val;
+  }
+};
+
+static auto test = torch::jit::class_<Foo>("_TorchScriptTesting_Foo")
+                       .def(torch::jit::init<int64_t, int64_t>())
+                       // .def(torch::jit::init<>())
+                       .def("info", &Foo::info)
+                       .def("increment", &Foo::increment)
+                       .def("add", &Foo::add)
+                       .def("combine", &Foo::combine);
+
+static auto testStack =
+    torch::jit::class_<Stack<std::string>>("_TorchScriptTesting_StackString")
+        .def(torch::jit::init<std::vector<std::string>>())
+        .def("push", &Stack<std::string>::push)
+        .def("pop", &Stack<std::string>::pop);
+
+} // namespace
+
+} // namespace jit
+} // namespace torch