Add IpAddr <-> ipaddress.IPv(4/6)Address conversion

Author: mhils

newsfragments/3197.added.md

@@ -0,0 +1 @@
+Add support for converting to and from Python's `ipaddress.IPv4Address`/`ipaddress.IPv6Address` and `std::net::IpAddr`.

src/conversions/std/ipaddr.rs

@@ -0,0 +1,110 @@
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+
+use crate::exceptions::PyValueError;
+use crate::sync::GILOnceCell;
+use crate::types::PyType;
+use crate::{intern, FromPyObject, IntoPy, Py, PyAny, PyObject, PyResult, Python, ToPyObject};
+
+impl FromPyObject<'_> for IpAddr {
+    fn extract(obj: &PyAny) -> PyResult<Self> {
+        match obj.getattr(intern!(obj.py(), "packed")) {
+            Ok(packed) => {
+                if let Ok(packed) = packed.extract::<[u8; 4]>() {
+                    Ok(IpAddr::V4(Ipv4Addr::from(packed)))
+                } else if let Ok(packed) = packed.extract::<[u8; 16]>() {
+                    Ok(IpAddr::V6(Ipv6Addr::from(packed)))
+                } else {
+                    Err(PyValueError::new_err("invalid packed length"))
+                }
+            }
+            Err(_) => {
+                // We don't have a .packed attribute, so we try to construct an IP from str().
+                obj.str()?.to_str()?.parse().map_err(PyValueError::new_err)
+            }
+        }
+    }
+}
+
+impl ToPyObject for Ipv4Addr {
+    fn to_object(&self, py: Python<'_>) -> PyObject {
+        static IPV4_ADDRESS: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+        IPV4_ADDRESS
+            .get_or_try_init_type_ref(py, "ipaddress", "IPv4Address")
+            .expect("failed to load ipaddress.IPv4Address")
+            .call1((u32::from_be_bytes(self.octets()),))
+            .expect("failed to construct ipaddress.IPv4Address")
+            .to_object(py)
+    }
+}
+
+impl ToPyObject for Ipv6Addr {
+    fn to_object(&self, py: Python<'_>) -> PyObject {
+        static IPV6_ADDRESS: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+        IPV6_ADDRESS
+            .get_or_try_init_type_ref(py, "ipaddress", "IPv6Address")
+            .expect("failed to load ipaddress.IPv6Address")
+            .call1((u128::from_be_bytes(self.octets()),))
+            .expect("failed to construct ipaddress.IPv6Address")
+            .to_object(py)
+    }
+}
+
+impl ToPyObject for IpAddr {
+    fn to_object(&self, py: Python<'_>) -> PyObject {
+        match self {
+            IpAddr::V4(ip) => ip.to_object(py),
+            IpAddr::V6(ip) => ip.to_object(py),
+        }
+    }
+}
+
+impl IntoPy<PyObject> for IpAddr {
+    fn into_py(self, py: Python<'_>) -> PyObject {
+        self.to_object(py)
+    }
+}
+
+#[cfg(test)]
+mod test_ipaddr {
+    use std::str::FromStr;
+
+    use crate::types::PyString;
+
+    use super::*;
+
+    #[test]
+    fn test_roundtrip() {
+        Python::with_gil(|py| {
+            fn roundtrip(py: Python<'_>, ip: &str) {
+                let ip = IpAddr::from_str(ip).unwrap();
+                let py_cls = if ip.is_ipv4() {
+                    "IPv4Address"
+                } else {
+                    "IPv6Address"
+                };
+
+                let pyobj = ip.into_py(py);
+                let repr = pyobj.as_ref(py).repr().unwrap().to_string_lossy();
+                assert_eq!(repr, format!("{}('{}')", py_cls, ip));
+
+                let ip2: IpAddr = pyobj.extract(py).unwrap();
+                assert_eq!(ip, ip2);
+            }
+            roundtrip(py, "127.0.0.1");
+            roundtrip(py, "::1");
+            roundtrip(py, "0.0.0.0");
+        });
+    }
+
+    #[test]
+    fn test_from_pystring() {
+        Python::with_gil(|py| {
+            let py_str = PyString::new(py, "0:0:0:0:0:0:0:1");
+            let ip: IpAddr = py_str.to_object(py).extract(py).unwrap();
+            assert_eq!(ip, IpAddr::from_str("::1").unwrap());
+
+            let py_str = PyString::new(py, "invalid");
+            assert!(py_str.to_object(py).extract::<IpAddr>(py).is_err());
+        });
+    }
+}

src/conversions/std/mod.rs

@@ -1,4 +1,5 @@
 mod array;
+mod ipaddr;
 mod map;
 mod num;
 mod osstr;

src/sync.rs

@@ -1,5 +1,5 @@
 //! Synchronization mechanisms based on the Python GIL.
-use crate::{types::PyString, Py, Python};
+use crate::{types::PyString, types::PyType, Py, PyErr, Python};
 use std::cell::UnsafeCell;
 
 /// Value with concurrent access protected by the GIL.
@@ -169,6 +169,21 @@ impl<T> GILOnceCell<T> {
     }
 }
 
+impl GILOnceCell<Py<PyType>> {
+    /// Get a reference to the contained Python type, initializing it if needed.
+    ///
+    /// This is a shorthand method for `get_or_init` which imports the type from Python on init.
+    pub(crate) fn get_or_try_init_type_ref<'py>(
+        &'py self,
+        py: Python<'py>,
+        module_name: &str,
+        attr_name: &str,
+    ) -> Result<&'py PyType, PyErr> {
+        self.get_or_try_init(py, || py.import(module_name)?.getattr(attr_name)?.extract())
+            .map(|ty| ty.as_ref(py))
+    }
+}
+
 /// Interns `text` as a Python string and stores a reference to it in static storage.
 ///
 /// A reference to the same Python string is returned on each invocation.