Expose unsafe_unwrap

This at least ensures we don't have to needlessly leak generators in the
tests, and covers similar use cases for consumers of libfringe.

benches/generator.rs

@@ -8,7 +8,6 @@
 extern crate test;
 extern crate fringe;
 
-use std::mem;
 use fringe::{OsStack, Generator};
 
 #[bench]
@@ -19,5 +18,5 @@ fn generate(b: &mut test::Bencher) {
   });
 
   b.iter(|| for _ in 0..10 { test::black_box(identity.resume(test::black_box(0))); });
-  mem::forget(identity);
+  unsafe { identity.unsafe_unwrap(); }
 }

src/generator.rs

@@ -201,7 +201,9 @@ impl<'a, Input, Output, Stack> Generator<'a, Input, Output, Stack>
     }
   }
 
-  unsafe fn unsafe_unwrap(mut self) -> Stack {
+  /// Extracts the stack from a generator without checking if the generator function has returned.
+  /// This will leave any pointers into the generator stack dangling, and won't run destructors.
+  pub unsafe fn unsafe_unwrap(mut self) -> Stack {
     ptr::drop_in_place(&mut self.stack_id.value);
     let stack = ptr::read(&mut self.stack.value);
     mem::forget(self);

tests/iterator.rs

@@ -8,7 +8,6 @@ extern crate fringe;
 
 use fringe::OsStack;
 use fringe::generator::Generator;
-use std::mem;
 
 #[test]
 fn producer() {
@@ -19,5 +18,5 @@ fn producer() {
   assert_eq!(gen.next(), Some(0));
   assert_eq!(gen.next(), Some(1));
   assert_eq!(gen.next(), Some(2));
-  mem::forget(gen);
+  unsafe { gen.unsafe_unwrap(); }
 }