Add _codecs.unregister()

vm/src/codecs.rs

@@ -2,7 +2,7 @@ use crate::{
     builtins::{PyBaseExceptionRef, PyBytesRef, PyStr, PyStrRef, PyTuple, PyTupleRef},
     common::{ascii, lock::PyRwLock},
     function::IntoPyObject,
-    PyContext, PyObject, PyObjectRef, PyResult, PyValue, TryFromObject, TypeProtocol,
+    IdProtocol, PyContext, PyObject, PyObjectRef, PyResult, PyValue, TryFromObject, TypeProtocol,
     VirtualMachine,
 };
 use std::borrow::Cow;
@@ -195,6 +195,24 @@ impl CodecsRegistry {
         Ok(())
     }
 
+    pub fn unregister(&self, search_function: PyObjectRef) -> PyResult<()> {
+        let mut inner = self.inner.write();
+        // Do nothing if search_path is not created yet or was cleared.
+        if inner.search_path.is_empty() {
+            return Ok(());
+        }
+        for (i, item) in inner.search_path.iter().enumerate() {
+            if item.get_id() == search_function.get_id() {
+                if !inner.search_cache.is_empty() {
+                    inner.search_cache.clear();
+                }
+                inner.search_path.remove(i);
+                return Ok(());
+            }
+        }
+        Ok(())
+    }
+
     pub fn lookup(&self, encoding: &str, vm: &VirtualMachine) -> PyResult<PyCodec> {
         let encoding = normalize_encoding_name(encoding);
         let inner = self.inner.read();

vm/src/stdlib/codecs.rs

@@ -16,6 +16,11 @@ mod _codecs {
         vm.state.codec_registry.register(search_function, vm)
     }
 
+    #[pyfunction]
+    fn unregister(search_function: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+        vm.state.codec_registry.unregister(search_function)
+    }
+
     #[pyfunction]
     fn lookup(encoding: PyStrRef, vm: &VirtualMachine) -> PyResult {
         vm.state