allow constructing Rc/RcMut from Const types too
This commit is contained in:
Daniel Micay
parent
8a15333c06
commit
4702667a62
1 changed files with 66 additions and 42 deletions
108
src/libstd/rc.rs
108
src/libstd/rc.rs
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@ -11,7 +11,11 @@
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/** Task-local reference counted smart pointers
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Task-local reference counted smart pointers are an alternative to managed boxes with deterministic
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destruction. They are restricted to containing `Owned` types in order to prevent cycles.
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destruction. They are restricted to containing types that are either `Owned` or `Const` (or both) to
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prevent cycles.
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Neither `Rc<T>` or `RcMut<T>` is ever `Owned` and `RcMut<T>` is never `Const`. If `T` is `Const`, a
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cycle cannot be created with `Rc<T>` because there is no way to modify it after creation.
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*/
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@ -30,16 +34,26 @@ pub struct Rc<T> {
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priv ptr: *mut RcBox<T>,
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}
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pub impl<T: Owned> Rc<T> {
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fn new(value: T) -> Rc<T> {
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unsafe {
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let ptr = malloc(sys::size_of::<RcBox<T>>() as size_t) as *mut RcBox<T>;
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assert!(!ptr::is_null(ptr));
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intrinsics::move_val_init(&mut *ptr, RcBox{value: value, count: 1});
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Rc{ptr: ptr}
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}
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priv impl<T> Rc<T> {
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unsafe fn new(value: T) -> Rc<T> {
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let ptr = malloc(sys::size_of::<RcBox<T>>() as size_t) as *mut RcBox<T>;
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assert!(!ptr::is_null(ptr));
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intrinsics::move_val_init(&mut *ptr, RcBox{value: value, count: 1});
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Rc{ptr: ptr}
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}
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}
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// FIXME: #6516: should be a static method
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pub fn rc_from_owned<T: Owned>(value: T) -> Rc<T> {
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unsafe { Rc::new(value) }
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}
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// FIXME: #6516: should be a static method
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pub fn rc_from_const<T: Const>(value: T) -> Rc<T> {
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unsafe { Rc::new(value) }
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}
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pub impl<T> Rc<T> {
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#[inline(always)]
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fn borrow<'r>(&'r self) -> &'r T {
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unsafe { cast::copy_lifetime(self, &(*self.ptr).value) }
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@ -48,7 +62,7 @@ pub impl<T: Owned> Rc<T> {
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#[unsafe_destructor]
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#[cfg(not(stage0))]
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impl<T: Owned> Drop for Rc<T> {
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impl<T> Drop for Rc<T> {
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fn finalize(&self) {
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unsafe {
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(*self.ptr).count -= 1;
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@ -62,7 +76,7 @@ impl<T: Owned> Drop for Rc<T> {
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#[unsafe_destructor]
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#[cfg(stage0)]
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impl<T: Owned> Drop for Rc<T> {
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impl<T> Drop for Rc<T> {
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fn finalize(&self) {
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unsafe {
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(*self.ptr).count -= 1;
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@ -75,7 +89,7 @@ impl<T: Owned> Drop for Rc<T> {
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}
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impl<T: Owned> Clone for Rc<T> {
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impl<T> Clone for Rc<T> {
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/// Return a shallow copy of the reference counted pointer.
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#[inline]
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fn clone(&self) -> Rc<T> {
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@ -86,11 +100,11 @@ impl<T: Owned> Clone for Rc<T> {
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}
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}
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impl<T: Owned + DeepClone> DeepClone for Rc<T> {
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impl<T: DeepClone> DeepClone for Rc<T> {
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/// Return a deep copy of the reference counted pointer.
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#[inline]
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fn deep_clone(&self) -> Rc<T> {
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Rc::new(self.borrow().deep_clone())
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unsafe { Rc::new(self.borrow().deep_clone()) }
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}
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}
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@ -101,7 +115,7 @@ mod test_rc {
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#[test]
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fn test_clone() {
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let x = Rc::new(Cell(5));
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let x = rc_from_owned(Cell(5));
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let y = x.clone();
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do x.borrow().with_mut_ref |inner| {
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*inner = 20;
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@ -111,7 +125,7 @@ mod test_rc {
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#[test]
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fn test_deep_clone() {
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let x = Rc::new(Cell(5));
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let x = rc_from_owned(Cell(5));
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let y = x.deep_clone();
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do x.borrow().with_mut_ref |inner| {
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*inner = 20;
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@ -121,13 +135,13 @@ mod test_rc {
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#[test]
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fn test_simple() {
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let x = Rc::new(5);
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let x = rc_from_const(5);
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assert_eq!(*x.borrow(), 5);
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}
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#[test]
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fn test_simple_clone() {
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let x = Rc::new(5);
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let x = rc_from_const(5);
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let y = x.clone();
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assert_eq!(*x.borrow(), 5);
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assert_eq!(*y.borrow(), 5);
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@ -135,7 +149,7 @@ mod test_rc {
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#[test]
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fn test_destructor() {
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let x = Rc::new(~5);
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let x = rc_from_owned(~5);
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assert_eq!(**x.borrow(), 5);
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}
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}
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@ -167,16 +181,26 @@ pub struct RcMut<T> {
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priv ptr: *mut RcMutBox<T>,
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}
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pub impl<T: Owned> RcMut<T> {
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fn new(value: T) -> RcMut<T> {
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unsafe {
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let ptr = malloc(sys::size_of::<RcMutBox<T>>() as size_t) as *mut RcMutBox<T>;
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assert!(!ptr::is_null(ptr));
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intrinsics::move_val_init(&mut *ptr, RcMutBox{value: value, count: 1, borrow: Nothing});
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RcMut{ptr: ptr}
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}
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priv impl<T> RcMut<T> {
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unsafe fn new(value: T) -> RcMut<T> {
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let ptr = malloc(sys::size_of::<RcMutBox<T>>() as size_t) as *mut RcMutBox<T>;
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assert!(!ptr::is_null(ptr));
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intrinsics::move_val_init(&mut *ptr, RcMutBox{value: value, count: 1, borrow: Nothing});
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RcMut{ptr: ptr}
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}
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}
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// FIXME: #6516: should be a static method
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pub fn rc_mut_from_owned<T: Owned>(value: T) -> RcMut<T> {
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unsafe { RcMut::new(value) }
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}
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// FIXME: #6516: should be a static method
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pub fn rc_mut_from_const<T: Const>(value: T) -> RcMut<T> {
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unsafe { RcMut::new(value) }
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}
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pub impl<T> RcMut<T> {
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/// Fails if there is already a mutable borrow of the box
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#[inline]
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fn with_borrow<U>(&self, f: &fn(&T) -> U) -> U {
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@ -205,7 +229,7 @@ pub impl<T: Owned> RcMut<T> {
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#[unsafe_destructor]
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#[cfg(not(stage0))]
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impl<T: Owned> Drop for RcMut<T> {
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impl<T> Drop for RcMut<T> {
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fn finalize(&self) {
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unsafe {
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(*self.ptr).count -= 1;
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@ -219,7 +243,7 @@ impl<T: Owned> Drop for RcMut<T> {
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#[unsafe_destructor]
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#[cfg(stage0)]
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impl<T: Owned> Drop for RcMut<T> {
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impl<T> Drop for RcMut<T> {
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fn finalize(&self) {
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unsafe {
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(*self.ptr).count -= 1;
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@ -231,7 +255,7 @@ impl<T: Owned> Drop for RcMut<T> {
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}
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}
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impl<T: Owned> Clone for RcMut<T> {
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impl<T> Clone for RcMut<T> {
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/// Return a shallow copy of the reference counted pointer.
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#[inline]
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fn clone(&self) -> RcMut<T> {
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@ -242,13 +266,13 @@ impl<T: Owned> Clone for RcMut<T> {
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}
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}
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impl<T: Owned + DeepClone> DeepClone for RcMut<T> {
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impl<T: DeepClone> DeepClone for RcMut<T> {
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/// Return a deep copy of the reference counted pointer.
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#[inline]
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fn deep_clone(&self) -> RcMut<T> {
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do self.with_borrow |x| {
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// FIXME: #6497: should avoid freeze (slow)
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RcMut::new(x.deep_clone())
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unsafe { RcMut::new(x.deep_clone()) }
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}
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}
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}
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@ -259,7 +283,7 @@ mod test_rc_mut {
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#[test]
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fn test_clone() {
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let x = RcMut::new(5);
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let x = rc_mut_from_owned(5);
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let y = x.clone();
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do x.with_mut_borrow |value| {
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*value = 20;
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@ -271,7 +295,7 @@ mod test_rc_mut {
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#[test]
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fn test_deep_clone() {
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let x = RcMut::new(5);
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let x = rc_mut_from_const(5);
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let y = x.deep_clone();
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do x.with_mut_borrow |value| {
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*value = 20;
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@ -283,7 +307,7 @@ mod test_rc_mut {
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#[test]
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fn borrow_many() {
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let x = RcMut::new(5);
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let x = rc_mut_from_owned(5);
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let y = x.clone();
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do x.with_borrow |a| {
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@ -299,7 +323,7 @@ mod test_rc_mut {
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#[test]
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fn modify() {
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let x = RcMut::new(5);
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let x = rc_mut_from_const(5);
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let y = x.clone();
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do y.with_mut_borrow |a| {
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@ -314,14 +338,14 @@ mod test_rc_mut {
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#[test]
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fn release_immutable() {
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let x = RcMut::new(5);
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let x = rc_mut_from_owned(5);
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do x.with_borrow |_| {}
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do x.with_mut_borrow |_| {}
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}
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#[test]
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fn release_mutable() {
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let x = RcMut::new(5);
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let x = rc_mut_from_const(5);
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do x.with_mut_borrow |_| {}
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do x.with_borrow |_| {}
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}
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@ -329,7 +353,7 @@ mod test_rc_mut {
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#[test]
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#[should_fail]
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fn frozen() {
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let x = RcMut::new(5);
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let x = rc_mut_from_owned(5);
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let y = x.clone();
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do x.with_borrow |_| {
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@ -341,7 +365,7 @@ mod test_rc_mut {
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#[test]
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#[should_fail]
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fn mutable_dupe() {
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let x = RcMut::new(5);
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let x = rc_mut_from_const(5);
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let y = x.clone();
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do x.with_mut_borrow |_| {
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@ -353,7 +377,7 @@ mod test_rc_mut {
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#[test]
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#[should_fail]
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fn mutable_freeze() {
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let x = RcMut::new(5);
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let x = rc_mut_from_owned(5);
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let y = x.clone();
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do x.with_mut_borrow |_| {
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@ -365,7 +389,7 @@ mod test_rc_mut {
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#[test]
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#[should_fail]
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fn restore_freeze() {
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let x = RcMut::new(5);
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let x = rc_mut_from_const(5);
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let y = x.clone();
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do x.with_borrow |_| {
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