feat: Adds the Bound<'_, PyMappingProxy> type

newsfragments/4644.added.md

@@ -0,0 +1 @@
+New `PyMappingProxy` struct corresponing to the `mappingproxy` class in Python. 

pyo3-ffi/src/descrobject.rs

@@ -1,6 +1,6 @@
 use crate::methodobject::PyMethodDef;
 use crate::object::{PyObject, PyTypeObject};
-use crate::Py_ssize_t;
+use crate::{PyObject_TypeCheck, Py_ssize_t};
 use std::os::raw::{c_char, c_int, c_void};
 use std::ptr;
 
@@ -68,6 +68,11 @@ extern "C" {
     pub fn PyWrapper_New(arg1: *mut PyObject, arg2: *mut PyObject) -> *mut PyObject;
 }
 
+#[inline]
+pub unsafe fn PyDictProxy_Check(op: *mut PyObject) -> c_int {
+    PyObject_TypeCheck(op, std::ptr::addr_of_mut!(PyDictProxy_Type))
+}
+
 /// Represents the [PyMemberDef](https://docs.python.org/3/c-api/structures.html#c.PyMemberDef)
 /// structure.
 ///

src/conversions/std/map.rs

@@ -7,7 +7,10 @@ use crate::ToPyObject;
 use crate::{
     conversion::IntoPyObject,
     instance::Bound,
-    types::{any::PyAnyMethods, dict::PyDictMethods, PyDict},
+    types::{
+        any::PyAnyMethods, dict::PyDictMethods, mappingproxy::PyMappingProxyMethods, PyDict,
+        PyMappingProxy,
+    },
     FromPyObject, IntoPy, PyAny, PyErr, PyObject, Python,
 };
 
@@ -162,9 +165,19 @@ where
     S: hash::BuildHasher + Default,
 {
     fn extract_bound(ob: &Bound<'py, PyAny>) -> Result<Self, PyErr> {
-        let dict = ob.downcast::<PyDict>()?;
-        let mut ret = collections::HashMap::with_capacity_and_hasher(dict.len(), S::default());
-        for (k, v) in dict {
+        if let Ok(dict) = ob.downcast::<PyDict>() {
+            let mut ret = collections::HashMap::with_capacity_and_hasher(dict.len(), S::default());
+            for (k, v) in dict {
+                ret.insert(k.extract()?, v.extract()?);
+            }
+            return Ok(ret);
+        }
+
+        let mappingproxy = ob.downcast::<PyMappingProxy>()?;
+        let mut ret =
+            collections::HashMap::with_capacity_and_hasher(mappingproxy.len()?, S::default());
+        for res in mappingproxy.try_iter()? {
+            let (k, v) = res?;
             ret.insert(k.extract()?, v.extract()?);
         }
         Ok(ret)
@@ -182,9 +195,18 @@ where
     V: FromPyObject<'py>,
 {
     fn extract_bound(ob: &Bound<'py, PyAny>) -> Result<Self, PyErr> {
-        let dict = ob.downcast::<PyDict>()?;
+        if let Ok(dict) = ob.downcast::<PyDict>() {
+            let mut ret = collections::BTreeMap::new();
+            for (k, v) in dict {
+                ret.insert(k.extract()?, v.extract()?);
+            }
+            return Ok(ret);
+        }
+
+        let mappingproxy = ob.downcast::<PyMappingProxy>()?;
         let mut ret = collections::BTreeMap::new();
-        for (k, v) in dict {
+        for res in mappingproxy.try_iter()? {
+            let (k, v) = res?;
             ret.insert(k.extract()?, v.extract()?);
         }
         Ok(ret)

src/prelude.rs

@@ -38,6 +38,7 @@ pub use crate::types::float::PyFloatMethods;
 pub use crate::types::frozenset::PyFrozenSetMethods;
 pub use crate::types::list::PyListMethods;
 pub use crate::types::mapping::PyMappingMethods;
+pub use crate::types::mappingproxy::PyMappingProxyMethods;
 pub use crate::types::module::PyModuleMethods;
 pub use crate::types::sequence::PySequenceMethods;
 pub use crate::types::set::PySetMethods;

src/sealed.rs

@@ -1,7 +1,7 @@
 use crate::types::{
     PyBool, PyByteArray, PyBytes, PyCapsule, PyComplex, PyDict, PyFloat, PyFrozenSet, PyList,
-    PyMapping, PyModule, PySequence, PySet, PySlice, PyString, PyTraceback, PyTuple, PyType,
-    PyWeakref, PyWeakrefProxy, PyWeakrefReference,
+    PyMapping, PyMappingProxy, PyModule, PySequence, PySet, PySlice, PyString, PyTraceback,
+    PyTuple, PyType, PyWeakref, PyWeakrefProxy, PyWeakrefReference,
 };
 use crate::{ffi, Bound, PyAny, PyResult};
 
@@ -33,6 +33,7 @@ impl Sealed for Bound<'_, PyFloat> {}
 impl Sealed for Bound<'_, PyFrozenSet> {}
 impl Sealed for Bound<'_, PyList> {}
 impl Sealed for Bound<'_, PyMapping> {}
+impl Sealed for Bound<'_, PyMappingProxy> {}
 impl Sealed for Bound<'_, PyModule> {}
 impl Sealed for Bound<'_, PySequence> {}
 impl Sealed for Bound<'_, PySet> {}

src/types/dict.rs

@@ -780,7 +780,7 @@ where
 }
 
 /// Represents a tuple which can be used as a PyDict item.
-trait PyDictItem<'py> {
+pub trait PyDictItem<'py> {
     type K: IntoPyObject<'py>;
     type V: IntoPyObject<'py>;
     fn unpack(self) -> (Self::K, Self::V);