alloc using PyMem functions

src/alloc.rs

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+use std::alloc::{GlobalAlloc, Layout};
+use std::ffi::c_void;
+
+struct PyMemAllocator {}
+
+#[global_allocator]
+static ALLOCATOR: PyMemAllocator = PyMemAllocator {};
+
+unsafe impl Sync for PyMemAllocator {}
+
+unsafe impl GlobalAlloc for PyMemAllocator {
+    #[inline]
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        unsafe { pyo3_ffi::PyMem_Malloc(layout.size()) as *mut u8 }
+    }
+
+    #[inline]
+    unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
+        unsafe { pyo3_ffi::PyMem_Free(ptr as *mut c_void) }
+    }
+
+    #[inline]
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        unsafe {
+            let len = layout.size();
+            let ptr = pyo3_ffi::PyMem_Malloc(len) as *mut u8;
+            core::ptr::write_bytes(ptr, 0, len);
+            ptr
+        }
+    }
+
+    #[inline]
+    unsafe fn realloc(&self, ptr: *mut u8, _layout: Layout, new_size: usize) -> *mut u8 {
+        unsafe { pyo3_ffi::PyMem_Realloc(ptr as *mut c_void, new_size) as *mut u8 }
+    }
+}

src/deserialize/backend/yyjson.rs

@@ -4,7 +4,6 @@ use crate::deserialize::pyobject::*;
 use crate::deserialize::DeserializeError;
 use crate::ffi::yyjson::*;
 use crate::str::unicode_from_str;
-use crate::typeref::{yyjson_init, YYJSON_ALLOC, YYJSON_BUFFER_SIZE};
 use core::ffi::c_char;
 use core::ptr::{null, null_mut, NonNull};
 use std::borrow::Cow;
@@ -57,25 +56,52 @@ fn unsafe_yyjson_get_next_non_container(val: *mut yyjson_val) -> *mut yyjson_val
     unsafe { ((val as *mut u8).add(YYJSON_VAL_SIZE)) as *mut yyjson_val }
 }
 
+type DeserializeBuffer = Vec<core::mem::MaybeUninit<u8>>;
+
+const MINIMUM_BUFFER_CAPACITY: usize = 4096 - core::mem::size_of::<DeserializeBuffer>();
+
 pub(crate) fn deserialize(
     data: &'static str,
 ) -> Result<NonNull<pyo3_ffi::PyObject>, DeserializeError<'static>> {
+    let buffer_capacity = usize::max(
+        MINIMUM_BUFFER_CAPACITY,
+        yyjson_read_max_memory_usage(data.len()),
+    );
+    let mut buffer: DeserializeBuffer = Vec::with_capacity(buffer_capacity);
+    let mut alloc = crate::ffi::yyjson::yyjson_alc {
+        malloc: None,
+        realloc: None,
+        free: None,
+        ctx: null_mut(),
+    };
+    let alloc_ptr = core::ptr::addr_of_mut!(alloc);
+    unsafe {
+        crate::ffi::yyjson::yyjson_alc_pool_init(
+            alloc_ptr,
+            buffer.as_mut_ptr().cast::<core::ffi::c_void>(),
+            buffer_capacity,
+        );
+    }
+
     let mut err = yyjson_read_err {
         code: YYJSON_READ_SUCCESS,
         msg: null(),
         pos: 0,
     };
-    let doc = if yyjson_read_max_memory_usage(data.len()) < YYJSON_BUFFER_SIZE {
-        read_doc_with_buffer(data, &mut err)
-    } else {
-        read_doc_default(data, &mut err)
+
+    let doc = unsafe {
+        yyjson_read_opts(
+            data.as_ptr() as *mut c_char,
+            data.len(),
+            alloc_ptr as *const crate::ffi::yyjson::yyjson_alc,
+            &mut err,
+        )
     };
     if unlikely!(doc.is_null()) {
         let msg: Cow<str> = unsafe { core::ffi::CStr::from_ptr(err.msg).to_string_lossy() };
         Err(DeserializeError::from_yyjson(msg, err.pos as i64, data))
     } else {
         let val = yyjson_doc_get_root(doc);
-
         if unlikely!(!unsafe_yyjson_is_ctn(val)) {
             let pyval = match ElementType::from_tag(val) {
                 ElementType::String => parse_yy_string(val),
@@ -85,8 +111,8 @@ pub(crate) fn deserialize(
                 ElementType::Null => parse_none(),
                 ElementType::True => parse_true(),
                 ElementType::False => parse_false(),
-                ElementType::Array => unreachable!(),
-                ElementType::Object => unreachable!(),
+                ElementType::Array => unreachable_unchecked!(),
+                ElementType::Object => unreachable_unchecked!(),
             };
             unsafe { yyjson_doc_free(doc) };
             Ok(pyval)
@@ -110,21 +136,6 @@ pub(crate) fn deserialize(
     }
 }
 
-fn read_doc_default(data: &'static str, err: &mut yyjson_read_err) -> *mut yyjson_doc {
-    unsafe { yyjson_read_opts(data.as_ptr() as *mut c_char, data.len(), null_mut(), err) }
-}
-
-fn read_doc_with_buffer(data: &'static str, err: &mut yyjson_read_err) -> *mut yyjson_doc {
-    unsafe {
-        yyjson_read_opts(
-            data.as_ptr() as *mut c_char,
-            data.len(),
-            &YYJSON_ALLOC.get_or_init(yyjson_init).alloc,
-            err,
-        )
-    }
-}
-
 enum ElementType {
     String,
     Uint64,
@@ -149,7 +160,7 @@ impl ElementType {
             TAG_FALSE => Self::False,
             TAG_ARRAY => Self::Array,
             TAG_OBJECT => Self::Object,
-            _ => unreachable!(),
+            _ => unreachable_unchecked!(),
         }
     }
 }
@@ -221,8 +232,8 @@ fn populate_yy_array(list: *mut pyo3_ffi::PyObject, elem: *mut yyjson_val) {
                     ElementType::Null => parse_none(),
                     ElementType::True => parse_true(),
                     ElementType::False => parse_false(),
-                    ElementType::Array => unreachable!(),
-                    ElementType::Object => unreachable!(),
+                    ElementType::Array => unreachable_unchecked!(),
+                    ElementType::Object => unreachable_unchecked!(),
                 };
                 append_to_list!(dptr, pyval.as_ptr());
             }
@@ -283,8 +294,8 @@ fn populate_yy_object(dict: *mut pyo3_ffi::PyObject, elem: *mut yyjson_val) {
                     ElementType::Null => parse_none(),
                     ElementType::True => parse_true(),
                     ElementType::False => parse_false(),
-                    ElementType::Array => unreachable!(),
-                    ElementType::Object => unreachable!(),
+                    ElementType::Array => unreachable_unchecked!(),
+                    ElementType::Object => unreachable_unchecked!(),
                 };
                 add_to_dict!(dict, pykey, pyval.as_ptr());
                 reverse_pydict_incref!(pykey);

src/deserialize/pyobject.rs

@@ -16,7 +16,7 @@ pub fn get_unicode_key(key_str: &str) -> *mut pyo3_ffi::PyObject {
         unsafe {
             let entry = KEY_MAP
                 .get_mut()
-                .unwrap_or_else(|| unreachable!())
+                .unwrap_or_else(|| unreachable_unchecked!())
                 .entry(&hash)
                 .or_insert_with(
                     || hash,

src/lib.rs

@@ -22,6 +22,7 @@ extern crate unwinding;
 #[macro_use]
 mod util;
 
+mod alloc;
 mod deserialize;
 mod ffi;
 mod opt;

src/typeref.rs

@@ -2,15 +2,9 @@
 
 use crate::ffi::orjson_fragmenttype_new;
 use core::ffi::c_char;
-#[cfg(feature = "yyjson")]
-use core::ffi::c_void;
-#[cfg(feature = "yyjson")]
-use core::mem::MaybeUninit;
 use core::ptr::{null_mut, NonNull};
 use once_cell::race::{OnceBool, OnceBox};
 use pyo3_ffi::*;
-#[cfg(feature = "yyjson")]
-use std::cell::UnsafeCell;
 
 pub struct NumpyTypes {
     pub array: *mut PyTypeObject,
@@ -76,48 +70,6 @@ pub static mut DESCR_STR: *mut PyObject = null_mut();
 pub static mut VALUE_STR: *mut PyObject = null_mut();
 pub static mut INT_ATTR_STR: *mut PyObject = null_mut();
 
-#[cfg(feature = "yyjson")]
-pub const YYJSON_BUFFER_SIZE: usize = 1024 * 1024 * 8;
-
-#[cfg(feature = "yyjson")]
-#[repr(align(64))]
-struct YYJSONBuffer(UnsafeCell<MaybeUninit<[u8; YYJSON_BUFFER_SIZE]>>);
-
-#[cfg(feature = "yyjson")]
-pub struct YYJSONAlloc {
-    pub alloc: crate::ffi::yyjson::yyjson_alc,
-    _buffer: Box<YYJSONBuffer>,
-}
-
-#[cfg(feature = "yyjson")]
-pub static mut YYJSON_ALLOC: OnceBox<YYJSONAlloc> = OnceBox::new();
-
-#[cfg(feature = "yyjson")]
-pub fn yyjson_init() -> Box<YYJSONAlloc> {
-    // Using unsafe to ensure allocation happens on the heap without going through the stack
-    // so we don't stack overflow in debug mode. Once rust-lang/rust#63291 is stable (Box::new_uninit)
-    // we can use that instead.
-    let layout = std::alloc::Layout::new::<YYJSONBuffer>();
-    let buffer = unsafe { Box::from_raw(std::alloc::alloc(layout).cast::<YYJSONBuffer>()) };
-    let mut alloc = crate::ffi::yyjson::yyjson_alc {
-        malloc: None,
-        realloc: None,
-        free: None,
-        ctx: null_mut(),
-    };
-    unsafe {
-        crate::ffi::yyjson::yyjson_alc_pool_init(
-            &mut alloc,
-            buffer.0.get().cast::<c_void>(),
-            YYJSON_BUFFER_SIZE,
-        );
-    }
-    Box::new(YYJSONAlloc {
-        alloc,
-        _buffer: buffer,
-    })
-}
-
 #[allow(non_upper_case_globals)]
 pub static mut JsonEncodeError: *mut PyObject = null_mut();
 #[allow(non_upper_case_globals)]

src/util.rs

@@ -309,3 +309,9 @@ macro_rules! popcnt {
         core::mem::transmute::<u32, i32>($val).count_ones() as usize
     };
 }
+
+macro_rules! unreachable_unchecked {
+    () => {
+        unsafe { core::hint::unreachable_unchecked() }
+    };
+}