More verbose reporting about re-reserving same region

Cargo.toml

@@ -5,7 +5,7 @@ edition = "2024"
 [dependencies]
 
 [lints]
-rust = { nonstandard_style = "allow" }
+rust = { nonstandard_style = "allow", drop_bounds = "allow" }
 
 [workspace]
 

src/virtual_memory.rs

@@ -1,3 +1,5 @@
+use std::fs::read_to_string;
+
 pub unsafe trait VirtualMemoryApi: Sized + Drop {
     type Reservation<'s>: Reservation + 's
     where
@@ -5,20 +7,47 @@ pub unsafe trait VirtualMemoryApi: Sized + Drop {
 
     fn getPageSize(&self) -> usize;
 
-    fn reserveMemory<'s>(
-        &'s self,
-        extend: ReservationToExtend<&Self::Reservation<'s>>,
-        pagesCount: usize,
-    ) -> Option<Self::Reservation<'s>>;
-}
+    fn reserveMemory<'s>(&'s self, pagesCount: usize) -> Option<Self::Reservation<'s>>;
 
-pub enum ReservationToExtend<T> {
-    ReserveAnywhere,
-    TryExtend(T),
+    unsafe fn extendReservation<'s>(
+        &'s self,
+        base: &Self::Reservation<'s>,
+        pagesCount: usize,
+    ) -> ExtendResult<Self::Reservation<'s>>;
 }
 
 pub unsafe trait Reservation: Sized + Ord + Drop {
+    fn getPageSize(&self) -> usize;
+    fn pagesCount(&self) -> usize;
     unsafe fn commitPages(&mut self, indexOfFirst: usize, count: usize) -> *mut [u8];
     unsafe fn decommitPages(&mut self, indexOfFirst: usize, count: usize);
     unsafe fn release(self);
 }
+
+pub enum ExtendResult<T> {
+    OutOfMemory,
+    ContinuationIsBusy,
+    Success(T),
+}
+
+impl<T> ExtendResult<T> {
+    pub fn map<R>(&self, caster: impl FnOnce(&T) -> R) -> ExtendResult<R> {
+        match self {
+            ExtendResult::Success(v) => {
+                return ExtendResult::Success(caster(&v));
+            }
+            ExtendResult::ContinuationIsBusy => return ExtendResult::ContinuationIsBusy,
+            ExtendResult::OutOfMemory => return ExtendResult::OutOfMemory,
+        }
+    }
+
+    pub fn map_into<R>(self, caster: impl FnOnce(T) -> R) -> ExtendResult<R> {
+        match self {
+            ExtendResult::Success(v) => {
+                return ExtendResult::Success(caster(v));
+            }
+            ExtendResult::ContinuationIsBusy => return ExtendResult::ContinuationIsBusy,
+            ExtendResult::OutOfMemory => return ExtendResult::OutOfMemory,
+        }
+    }
+}