feat: Implement into_memory for memory manager

src/memory_manager.rs

@@ -155,6 +155,15 @@ impl<M: Memory> MemoryManager<M> {
             memory_manager: self.inner.clone(),
         }
     }
+
+    /// Returns the underlying memory.
+    ///
+    /// # Returns
+    /// - The underlying memory, if there is exactly one strong reference to the memory manager.  Please see [`Rc::try_unwrap`](https://doc.rust-lang.org/std/rc/struct.Rc.html#method.try_unwrap) for more details.
+    /// - None otherwise.
+    pub fn into_memory(self) -> Option<M> {
+        Rc::into_inner(self.inner).map(|inner| inner.into_inner().into_memory())
+    }
 }
 
 #[repr(C, packed)]
@@ -419,6 +428,11 @@ impl<M: Memory> MemoryManagerInner<M> {
         // Ceiling division.
         (num_pages + self.bucket_size_in_pages as u64 - 1) / self.bucket_size_in_pages as u64
     }
+
+    // Returns the underlying memory.
+    pub fn into_memory(self) -> M {
+        self.memory
+    }
 }
 
 struct Segment {

src/tests.rs

@@ -1,4 +1,5 @@
 use super::*;
+use crate::memory_manager::{MemoryId, MemoryManager};
 use std::cell::RefCell;
 use std::rc::Rc;
 
@@ -48,3 +49,20 @@ fn vec_exposes_init_err() {
     #[allow(unused_imports)]
     use crate::vec::InitError;
 }
+
+#[test]
+fn should_be_able_to_recover_memory_from_memory_manager() {
+    let raw_memory = DefaultMemoryImpl::default();
+    let memory_manager = MemoryManager::init(raw_memory);
+    let recovered_memory = memory_manager.into_memory();
+    assert!(recovered_memory.is_some());
+}
+
+#[test]
+fn should_fail_to_recover_memory_from_memory_manager_if_memory_is_in_use() {
+    let raw_memory = DefaultMemoryImpl::default();
+    let memory_manager = MemoryManager::init(raw_memory);
+    let _a_virtual_memory = memory_manager.get(MemoryId::new(0));
+    let recovered_memory = memory_manager.into_memory();
+    assert!(recovered_memory.is_none());
+}