Simplify deserialize input

src/decode.rs

@@ -2,7 +2,6 @@
 
 use crate::typeref;
 use pyo3::prelude::*;
-use pyo3::types::*;
 use serde::de::{self, DeserializeSeed, Deserializer, MapAccess, SeqAccess, Visitor};
 use smallvec::SmallVec;
 use std::borrow::Cow;
@@ -12,25 +11,25 @@ use std::os::raw::c_char;
 
 import_exception!(json, JSONDecodeError);
 
-pub fn deserialize(py: Python, obj: PyObject) -> PyResult<PyObject> {
-    let obj_ref = obj.as_ref(py);
-    let obj_ptr = obj_ref.get_type_ptr();
+pub fn deserialize(py: Python, ptr: *mut pyo3::ffi::PyObject) -> PyResult<PyObject> {
+    let obj_type_ptr = unsafe { (*ptr).ob_type };
     let data: Cow<str>;
-    if unsafe { obj_ptr == typeref::STR_PTR } {
+    if unsafe { obj_type_ptr == typeref::STR_PTR } {
+        let mut str_size: pyo3::ffi::Py_ssize_t = unsafe { std::mem::uninitialized() };
         data = unsafe {
-            Cow::Borrowed(std::str::from_utf8_unchecked(
-                <PyUnicode as PyTryFrom>::try_from_unchecked(obj_ref).as_bytes(),
-            ))
+            Cow::Borrowed(std::str::from_utf8_unchecked(std::slice::from_raw_parts(
+                pyo3::ffi::PyUnicode_AsUTF8AndSize(ptr, &mut str_size) as *const u8,
+                str_size as usize,
+            )))
         };
-    } else if unsafe { obj_ptr == typeref::BYTES_PTR } {
-        data = String::from_utf8_lossy(unsafe {
-            <PyBytes as PyTryFrom>::try_from_unchecked(obj_ref).as_bytes()
-        });
+    } else if unsafe { obj_type_ptr == typeref::BYTES_PTR } {
+        let buffer = unsafe { pyo3::ffi::PyBytes_AsString(ptr) as *const u8 };
+        let length = unsafe { pyo3::ffi::PyBytes_Size(ptr) as usize };
+        data = unsafe { String::from_utf8_lossy(std::slice::from_raw_parts(buffer, length)) };
     } else {
-        return Err(pyo3::exceptions::TypeError::py_err(format!(
-            "Input must be str or bytes, not: {}",
-            obj_ref.get_type().name()
-        )));
+        return Err(pyo3::exceptions::TypeError::py_err(
+            "Input must be str or bytes",
+        ));
     }
 
     let seed = JsonValue::new();

src/lib.rs

@@ -33,7 +33,7 @@ fn orjson(py: Python, m: &PyModule) -> PyResult<()> {
 /// Deserialize JSON to Python objects.
 #[pyfunction]
 pub fn loads(py: Python, obj: PyObject) -> PyResult<PyObject> {
-    decode::deserialize(py, obj)
+    decode::deserialize(py, obj.as_ptr())
 }
 
 /// dumps(obj, /)