diff rust/hg-cpython/src/dirstate/copymap.rs @ 43422:b9f791090211

rust-cpython: rename PyLeakedRef to PyLeaked

This series will make PyLeaked* behave more like a Python iterator, which
means mutation of the owner object will be allowed and the leaked reference
(i.e. the iterator) will be invalidated instead.

I'll add PyLeakedRef/PyLeakedRefMut structs which will represent a "borrowed"
state, and prevent the underlying value from being mutably borrowed while the
leaked reference is in use:

  let shared = self.inner_shared(py);
  let leaked = shared.leak_immutable();
  {
      let leaked_ref: PyLeakedRef<_> = leaked.borrow(py);
      shared.borrow_mut();  // panics since the underlying value is borrowed
  }
  shared.borrow_mut();  // allowed

The relation between PyLeaked* structs is quite similar to RefCell/Ref/RefMut,
but the implementation can't be reused because the borrowing state will have
to be shared across objects having no lifetime relation.

PyLeaked isn't named as PyLeakedCell since it isn't actually a cell in that
leaked.borrow_mut() will require &mut self.

--- a/rust/hg-cpython/src/dirstate/copymap.rs	Fri Oct 18 11:18:41 2019 -0400
+++ b/rust/hg-cpython/src/dirstate/copymap.rs	Sat Oct 12 19:10:51 2019 +0900
@@ -12,7 +12,7 @@
 use std::cell::RefCell;
 
 use crate::dirstate::dirstate_map::DirstateMap;
-use crate::ref_sharing::PyLeakedRef;
+use crate::ref_sharing::PyLeaked;
 use hg::{utils::hg_path::HgPathBuf, CopyMapIter};
 
 py_class!(pub class CopyMap |py| {
@@ -104,14 +104,14 @@
 
 py_shared_iterator!(
     CopyMapKeysIterator,
-    PyLeakedRef<CopyMapIter<'static>>,
+    PyLeaked<CopyMapIter<'static>>,
     CopyMap::translate_key,
     Option<PyBytes>
 );
 
 py_shared_iterator!(
     CopyMapItemsIterator,
-    PyLeakedRef<CopyMapIter<'static>>,
+    PyLeaked<CopyMapIter<'static>>,
     CopyMap::translate_key_value,
     Option<(PyBytes, PyBytes)>
 );