feat!: non-locking python conversion calls (#25)

`from_tket1` and `to_tket1` now receive the Global Interpreter Lock
(GIL) as a parameter rather than adquiring it internally.
This is more composable in cases where we want to reuse the GIL.

The locking methods are kept as utility functions.

BREAKING CHANGE: Renamed `SerialCircuit::to_tket1` to
`to_tket1_with_gil`, and `_from_tket1` to `from_tket1_with_gil`.

src/pytket.rs

@@ -4,24 +4,34 @@ use crate::circuit_json::SerialCircuit;
 use pyo3::prelude::*;
 use pythonize::{depythonize, pythonize};
 
-// #[pymethods]
 impl SerialCircuit {
     /// Create a new `SerialCircuit` from a `pytket.Circuit`.
-    pub fn _from_tket1(c: Py<PyAny>) -> Self {
-        Python::with_gil(|py| depythonize(c.call_method0(py, "to_dict").unwrap().as_ref(py)))
-            .unwrap()
+    pub fn from_tket1(circ: &PyAny) -> PyResult<Self> {
+        let circ = depythonize(circ.call_method0("to_dict").unwrap())?;
+        Ok(circ)
+    }
+
+    /// Create a new `SerialCircuit` from a `pytket.Circuit`.
+    ///
+    /// Utility function that calls [`SerialCircuit::from_tket1`] after acquiring the GIL.
+    pub fn from_tket1_with_gil(circ: Py<PyAny>) -> PyResult<Self> {
+        Python::with_gil(|py| Self::from_tket1(circ.as_ref(py)))
     }
 
     /// Convert a `SerialCircuit` to a `pytket.Circuit`.
-    pub fn to_tket1(&self) -> PyResult<Py<PyAny>> {
-        Python::with_gil(|py| {
-            let dict = pythonize(py, self).unwrap();
-            let circ_module = PyModule::import(py, "pytket.circuit")?;
+    pub fn to_tket1<'py>(&self, py: Python<'py>) -> PyResult<&'py PyAny> {
+        let dict = pythonize(py, self).unwrap();
+        let circ_module = PyModule::import(py, "pytket.circuit")?;
 
-            Ok(circ_module
-                .getattr("Circuit")?
-                .call_method1("from_dict", (dict,))?
-                .into())
-        })
+        circ_module
+            .getattr("Circuit")?
+            .call_method1("from_dict", (dict,))
+    }
+
+    /// Convert a `SerialCircuit` to a `pytket.Circuit`.
+    ///
+    /// Utility function that calls [`SerialCircuit::to_tket1`] after acquiring the GIL.
+    pub fn to_tket1_with_gil(&self) -> PyResult<Py<PyAny>> {
+        Python::with_gil(|py| self.to_tket1(py).map(|x| x.into()))
     }
 }