Initial reorg.

This is largely the same as #305, but updated for the current tree.

crates/misc/py/src/function.rs

@@ -0,0 +1,68 @@
+//! Support for a calling of a bounds (exported) function.
+
+extern crate alloc;
+
+use pyo3::prelude::*;
+use pyo3::types::PyTuple;
+
+use crate::value::{pyobj_to_value, value_to_pyobj};
+use alloc::rc::Rc;
+use core::cell::RefCell;
+
+use cranelift_codegen::ir;
+use wasmtime_interface_types::ModuleData;
+use wasmtime_jit::{Context, InstanceHandle};
+use wasmtime_runtime::Export;
+
+// TODO support non-export functions
+#[pyclass]
+pub struct Function {
+    pub context: Rc<RefCell<Context>>,
+    pub instance: InstanceHandle,
+    pub export_name: String,
+    pub args_types: Vec<ir::Type>,
+    pub data: Rc<ModuleData>,
+}
+
+impl Function {
+    pub fn get_signature(&self) -> ir::Signature {
+        let mut instance = self.instance.clone();
+        if let Some(Export::Function { signature, .. }) = instance.lookup(&self.export_name) {
+            signature
+        } else {
+            panic!()
+        }
+    }
+}
+
+#[pymethods]
+impl Function {
+    #[__call__]
+    #[args(args = "*")]
+    fn call(&self, py: Python, args: &PyTuple) -> PyResult<PyObject> {
+        let mut runtime_args = Vec::new();
+        for item in args.iter() {
+            runtime_args.push(pyobj_to_value(py, item)?);
+        }
+        let mut instance = self.instance.clone();
+        let mut cx = self.context.borrow_mut();
+        let results = self
+            .data
+            .invoke(
+                &mut cx,
+                &mut instance,
+                self.export_name.as_str(),
+                &runtime_args,
+            )
+            .map_err(crate::err2py)?;
+        let mut py_results = Vec::new();
+        for result in results {
+            py_results.push(value_to_pyobj(py, result)?);
+        }
+        if py_results.len() == 1 {
+            Ok(py_results[0].clone_ref(py))
+        } else {
+            Ok(PyTuple::new(py, py_results).to_object(py))
+        }
+    }
+}