add PyMemRawAllocator

newsfragments/6279.added.md

@@ -0,0 +1 @@
+Added `pyo3::pymem_alloc::PyMemRawAllocator`, a `GlobalAlloc` implementation backed by CPython's `PyMem_Raw*` (`PYMEM_DOMAIN_RAW`) allocator functions. Not registered as the global allocator automatically.

pyo3-ffi-check/macro/src/lib.rs

@@ -455,6 +455,8 @@ const MACRO_EXCLUSIONS: &[(&str, &str)] = &[
     ("Py_IsFalse", "not(Py_3_10)"),
     ("Py_IsTrue", "not(Py_3_10)"),
     ("Py_IsNone", "not(Py_3_10)"),
+    ("PyMem_New", ""),
+    ("PyMem_Resize", ""),
 ];
 
 // TODO: probably need to clean these up

pyo3-ffi/src/cpython/pymem.rs

@@ -1,22 +1,8 @@
+#[cfg(not(any(PyPy, GraalPy)))]
 use core::ffi::c_void;
+#[cfg(not(any(PyPy, GraalPy)))]
 use libc::size_t;
 
-extern_libpython! {
-    #[cfg_attr(PyPy, link_name = "PyPyMem_RawMalloc")]
-    pub fn PyMem_RawMalloc(size: size_t) -> *mut c_void;
-    #[cfg_attr(PyPy, link_name = "PyPyMem_RawCalloc")]
-    pub fn PyMem_RawCalloc(nelem: size_t, elsize: size_t) -> *mut c_void;
-    #[cfg_attr(PyPy, link_name = "PyPyMem_RawRealloc")]
-    pub fn PyMem_RawRealloc(ptr: *mut c_void, new_size: size_t) -> *mut c_void;
-    #[cfg_attr(PyPy, link_name = "PyPyMem_RawFree")]
-    pub fn PyMem_RawFree(ptr: *mut c_void);
-
-    // skipped _PyMem_GetCurrentAllocatorName
-    // skipped _PyMem_RawStrdup
-    // skipped _PyMem_Strdup
-    // skipped _PyMem_RawWcsdup
-}
-
 #[repr(C)]
 #[derive(Copy, Clone)]
 pub enum PyMemAllocatorDomain {

pyo3-ffi/src/pymem.rs

@@ -4,10 +4,59 @@ use libc::size_t;
 extern_libpython! {
     #[cfg_attr(PyPy, link_name = "PyPyMem_Malloc")]
     pub fn PyMem_Malloc(size: size_t) -> *mut c_void;
+
     #[cfg_attr(PyPy, link_name = "PyPyMem_Calloc")]
     pub fn PyMem_Calloc(nelem: size_t, elsize: size_t) -> *mut c_void;
+
     #[cfg_attr(PyPy, link_name = "PyPyMem_Realloc")]
     pub fn PyMem_Realloc(ptr: *mut c_void, new_size: size_t) -> *mut c_void;
+
     #[cfg_attr(PyPy, link_name = "PyPyMem_Free")]
     pub fn PyMem_Free(ptr: *mut c_void);
 }
+
+#[inline]
+pub unsafe fn PyMem_New<T>(n: size_t) -> *mut T {
+    if n > isize::MAX as size_t / size_of::<T>() as size_t {
+        core::ptr::null_mut()
+    } else {
+        PyMem_Malloc(n * size_of::<T>() as size_t).cast()
+    }
+}
+
+#[inline]
+pub unsafe fn PyMem_Resize<T>(p: &mut *mut T, n: size_t) {
+    *p = if n > isize::MAX as size_t / size_of::<T>() as size_t {
+        core::ptr::null_mut()
+    } else {
+        PyMem_Realloc(p.cast(), n * size_of::<T>() as size_t).cast()
+    };
+}
+
+extern_libpython! {
+    // Deprecated aliases:
+    //
+    // skipped PyMem_MALLOC
+    // skipped PyMem_NEW
+    // skipped PyMem_REALLOC
+    // skipped PyMem_RESIZE
+    // skipped PyMem_FREE
+    // skipped PyMem_Del
+    // skipped PyMem_DEL
+
+    #[cfg_attr(PyPy, link_name = "PyPyMem_RawMalloc")]
+    #[cfg(any(Py_3_13, not(Py_LIMITED_API)))]
+    pub fn PyMem_RawMalloc(size: size_t) -> *mut c_void;
+
+    #[cfg_attr(PyPy, link_name = "PyPyMem_RawCalloc")]
+    #[cfg(any(Py_3_13, not(Py_LIMITED_API)))]
+    pub fn PyMem_RawCalloc(nelem: size_t, elsize: size_t) -> *mut c_void;
+
+    #[cfg_attr(PyPy, link_name = "PyPyMem_RawRealloc")]
+    #[cfg(any(Py_3_13, not(Py_LIMITED_API)))]
+    pub fn PyMem_RawRealloc(ptr: *mut c_void, new_size: size_t) -> *mut c_void;
+
+    #[cfg_attr(PyPy, link_name = "PyPyMem_RawFree")]
+    #[cfg(any(Py_3_13, not(Py_LIMITED_API)))]
+    pub fn PyMem_RawFree(ptr: *mut c_void);
+}

src/lib.rs

@@ -104,6 +104,7 @@
 //! crate, which is not supported on all platforms.
 //!
 //! The following features enable interactions with other crates in the Rust ecosystem:
+//!
 //! - [`anyhow`]: Enables a conversion from [anyhow]’s [`Error`][anyhow_error] type to [`PyErr`].
 //! - [`chrono`]: Enables a conversion from [chrono]'s structures to the equivalent Python ones.
 //! - [`chrono-tz`]: Enables a conversion from [chrono-tz]'s `Tz` enum. Requires Python 3.9+.
@@ -480,6 +481,9 @@ pub mod inspect;
 // other paths to the same items. (e.g. `pyo3::types::PyAnyMethods` instead of `pyo3::prelude::PyAnyMethods`).
 pub mod prelude;
 
+#[cfg(any(Py_3_13, not(Py_LIMITED_API)))]
+pub mod pymem_alloc;
+
 /// Test readme and user guide
 #[cfg(doctest)]
 pub mod doc_test {