Use slice for list iteration

Author: ijl

src/encode.rs

@@ -97,10 +97,16 @@ impl<'p> Serialize for SerializePyObject {
             if unlikely!(self.recursion == RECURSION_LIMIT) {
                 err!("Recursion limit reached")
             }
+            let slice: &[*mut pyo3::ffi::PyObject] = unsafe {
+                std::slice::from_raw_parts(
+                    (*(self.ptr as *mut pyo3::ffi::PyListObject)).ob_item,
+                    ffi!(PyList_GET_SIZE(self.ptr)) as usize,
+                )
+            };
             let mut seq = serializer.serialize_seq(None).unwrap();
-            for elem in PyListIterator::new(self.ptr) {
+            for &elem in slice {
                 seq.serialize_element(&SerializePyObject {
-                    ptr: elem.as_ptr(),
+                    ptr: elem,
                     default: self.default,
                     opts: self.opts,
                     default_calls: self.default_calls,

src/iter.rs

@@ -2,39 +2,6 @@
 
 use std::ptr::NonNull;
 
-pub struct PyListIterator {
-    list: *mut pyo3::ffi::PyObject,
-    len: isize,
-    idx: isize,
-}
-
-impl PyListIterator {
-    pub fn new(list: *mut pyo3::ffi::PyObject) -> Self {
-        PyListIterator {
-            list: list,
-            len: ffi!(PyList_GET_SIZE(list)),
-            idx: 0,
-        }
-    }
-}
-
-impl Iterator for PyListIterator {
-    type Item = NonNull<pyo3::ffi::PyObject>;
-
-    #[inline]
-    fn next(&mut self) -> Option<NonNull<pyo3::ffi::PyObject>> {
-        if self.len == self.idx {
-            None
-        } else {
-            let item = unsafe {
-                NonNull::new_unchecked(ffi!(PyList_GET_ITEM(self.list, self.idx as isize)))
-            };
-            self.idx += 1;
-            Some(item)
-        }
-    }
-}
-
 pub struct PyTupleIterator {
     list: *mut pyo3::ffi::PyObject,
     len: isize,