librustc: Make the Drop trait use explicit self

Author: pcwalton

src/libcore/ops.rs

@@ -25,7 +25,7 @@ pub trait Owned {
 
 #[lang="drop"]
 pub trait Drop {
-    fn finalize();  // XXX: Rename to "drop"? --pcwalton
+    fn finalize(&self);  // XXX: Rename to "drop"? --pcwalton
 }
 
 #[lang="add"]

src/librustc/middle/trans/expr.rs

@@ -888,7 +888,7 @@ fn with_field_tys<R>(tcx: ty::ctxt,
         }
 
         ty::ty_class(did, ref substs) => {
-            let has_dtor = ty::ty_dtor(tcx, did).is_some();
+            let has_dtor = ty::ty_dtor(tcx, did).is_present();
             op(has_dtor, class_items_as_mutable_fields(tcx, did, substs))
         }
 

src/librustc/middle/trans/glue.rs

@@ -397,8 +397,14 @@ fn make_free_glue(bcx: block, v: ValueRef, t: ty::t) {
       }
       ty::ty_class(did, ref substs) => {
         // Call the dtor if there is one
-        do option::map_default(&ty::ty_dtor(bcx.tcx(), did), bcx) |dt_id| {
-            trans_class_drop(bcx, v, *dt_id, did, substs)
+        match ty::ty_dtor(bcx.tcx(), did) {
+            ty::NoDtor => bcx,
+            ty::LegacyDtor(ref dt_id) => {
+                trans_class_drop(bcx, v, *dt_id, did, substs, false)
+            }
+            ty::TraitDtor(ref dt_id) => {
+                trans_class_drop(bcx, v, *dt_id, did, substs, true)
+            }
         }
       }
       _ => bcx
@@ -410,7 +416,8 @@ fn trans_class_drop(bcx: block,
                     v0: ValueRef,
                     dtor_did: ast::def_id,
                     class_did: ast::def_id,
-                    substs: &ty::substs) -> block {
+                    substs: &ty::substs,
+                    take_ref: bool) -> block {
     let drop_flag = GEPi(bcx, v0, struct_dtor());
     do with_cond(bcx, IsNotNull(bcx, Load(bcx, drop_flag))) |cx| {
         let mut bcx = cx;
@@ -427,7 +434,18 @@ fn trans_class_drop(bcx: block,
         // just consist of the output pointer and the environment
         // (self)
         assert(params.len() == 2);
-        let self_arg = PointerCast(bcx, v0, params[1]);
+
+        // If we need to take a reference to the class (because it's using
+        // the Drop trait), do so now.
+        let llval;
+        if take_ref {
+            llval = alloca(bcx, val_ty(v0));
+            Store(bcx, v0, llval);
+        } else {
+            llval = v0;
+        }
+
+        let self_arg = PointerCast(bcx, llval, params[1]);
         let args = ~[bcx.fcx.llretptr, self_arg];
         Call(bcx, dtor_addr, args);
 
@@ -465,10 +483,13 @@ fn make_drop_glue(bcx: block, v0: ValueRef, t: ty::t) {
       ty::ty_class(did, ref substs) => {
         let tcx = bcx.tcx();
         match ty::ty_dtor(tcx, did) {
-          Some(dtor) => {
-            trans_class_drop(bcx, v0, dtor, did, substs)
+          ty::TraitDtor(dtor) => {
+            trans_class_drop(bcx, v0, dtor, did, substs, true)
           }
-          None => {
+          ty::LegacyDtor(dtor) => {
+            trans_class_drop(bcx, v0, dtor, did, substs, false)
+          }
+          ty::NoDtor => {
             // No dtor? Just the default case
             iter_structural_ty(bcx, v0, t, drop_ty)
           }

src/librustc/middle/trans/machine.rs

@@ -27,7 +27,7 @@ pub fn simplify_type(tcx: ty::ctxt, typ: ty::t) -> ty::t {
           // Reduce a class type to a record type in which all the fields are
           // simplified
           ty::ty_class(did, ref substs) => {
-            let simpl_fields = (if ty::ty_dtor(tcx, did).is_some() {
+            let simpl_fields = (if ty::ty_dtor(tcx, did).is_present() {
                 // remember the drop flag
                   ~[{ident: syntax::parse::token::special_idents::dtor,
                      mt: {ty: ty::mk_u8(tcx),

src/librustc/middle/trans/type_of.rs

@@ -199,7 +199,7 @@ fn type_of(cx: @crate_ctxt, t: ty::t) -> TypeRef {
 
         // include a byte flag if there is a dtor so that we know when we've
         // been dropped
-        if ty::ty_dtor(cx.tcx, did) != None {
+        if ty::ty_dtor(cx.tcx, did).is_present() {
             common::set_struct_body(llty, ~[T_struct(tys), T_i8()]);
         } else {
             common::set_struct_body(llty, ~[T_struct(tys)]);

src/librustc/middle/ty.rs

@@ -75,6 +75,7 @@ export enum_variants, substd_enum_variants, enum_is_univariant;
 export trait_methods, store_trait_methods, impl_traits;
 export enum_variant_with_id;
 export ty_dtor;
+export DtorKind, NoDtor, LegacyDtor, TraitDtor;
 export ty_param_bounds_and_ty;
 export ty_param_substs_and_ty;
 export ty_bool, mk_bool, type_is_bool;
@@ -1868,7 +1869,7 @@ fn type_needs_drop(cx: ctxt, ty: t) -> bool {
       }
       ty_class(did, ref substs) => {
          // Any class with a dtor needs a drop
-         ty_dtor(cx, did).is_some() || {
+         ty_dtor(cx, did).is_present() || {
              for vec::each(ty::class_items_as_fields(cx, did, substs)) |f| {
                  if type_needs_drop(cx, f.mt.ty) { accum = true; }
              }
@@ -3954,11 +3955,29 @@ fn item_path_str(cx: ctxt, id: ast::def_id) -> ~str {
     ast_map::path_to_str(item_path(cx, id), cx.sess.parse_sess.interner)
 }
 
+enum DtorKind {
+    NoDtor,
+    LegacyDtor(def_id),
+    TraitDtor(def_id)
+}
+
+impl DtorKind {
+    pure fn is_not_present(&const self) -> bool {
+        match *self {
+            NoDtor => true,
+            _ => false
+        }
+    }
+    pure fn is_present(&const self) -> bool {
+        !self.is_not_present()
+    }
+}
+
 /* If class_id names a class with a dtor, return Some(the dtor's id).
    Otherwise return none. */
-fn ty_dtor(cx: ctxt, class_id: def_id) -> Option<def_id> {
+fn ty_dtor(cx: ctxt, class_id: def_id) -> DtorKind {
     match cx.destructor_for_type.find(class_id) {
-        Some(method_def_id) => return Some(method_def_id),
+        Some(method_def_id) => return TraitDtor(method_def_id),
         None => {}  // Continue.
     }
 
@@ -3968,18 +3987,21 @@ fn ty_dtor(cx: ctxt, class_id: def_id) -> Option<def_id> {
                node: ast::item_class(@{ dtor: Some(dtor), _ }, _),
                _
            }, _)) =>
-               Some(local_def(dtor.node.id)),
+               LegacyDtor(local_def(dtor.node.id)),
            _ =>
-               None
+               NoDtor
        }
     }
     else {
-      csearch::class_dtor(cx.sess.cstore, class_id)
+      match csearch::class_dtor(cx.sess.cstore, class_id) {
+        None => NoDtor,
+        Some(did) => LegacyDtor(did),
+      }
     }
 }
 
 fn has_dtor(cx: ctxt, class_id: def_id) -> bool {
-    ty_dtor(cx, class_id).is_some()
+    ty_dtor(cx, class_id).is_present()
 }
 
 fn item_path(cx: ctxt, id: ast::def_id) -> ast_map::path {

src/libstd/arc.rs

@@ -229,7 +229,7 @@ struct PoisonOnFail {
 }
 
 impl PoisonOnFail : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         /* assert !*self.failed; -- might be false in case of cond.wait() */
         if task::failing() { *self.failed = true; }
     }

src/libstd/arena.rs

@@ -58,7 +58,7 @@ pub struct Arena {
 }
 
 impl Arena : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         unsafe {
             destroy_chunk(&self.head);
             for list::each(self.chunks) |chunk| {

src/libstd/c_vec.rs

@@ -42,11 +42,11 @@ struct DtorRes {
 }
 
 impl DtorRes : Drop {
-    fn finalize() {
-    match self.dtor {
-      option::None => (),
-      option::Some(f) => f()
-    }
+    fn finalize(&self) {
+        match self.dtor {
+          option::None => (),
+          option::Some(f) => f()
+        }
     }
 }
 

src/libstd/future.rs

@@ -28,7 +28,7 @@ pub struct Future<A> {
 // FIXME(#2829) -- futures should not be copyable, because they close
 // over fn~'s that have pipes and so forth within!
 impl<A> Future<A> : Drop {
-    fn finalize() {}
+    fn finalize(&self) {}
 }
 
 priv enum FutureState<A> {

src/libstd/net_tcp.rs

@@ -30,10 +30,10 @@ struct TcpSocket {
 }
 
 impl TcpSocket : Drop {
-    fn finalize() {
-    unsafe {
-        tear_down_socket_data(self.socket_data)
-    }
+    fn finalize(&self) {
+        unsafe {
+            tear_down_socket_data(self.socket_data)
+        }
     }
 }
 

src/libstd/sort.rs

@@ -1137,7 +1137,7 @@ mod big_tests {
     }
 
     impl LVal : Drop {
-        fn finalize() {
+        fn finalize(&self) {
             let x = unsafe { task::local_data::local_data_get(self.key) };
             match x {
                 Some(@y) => {

src/libstd/sync.rs

@@ -153,7 +153,7 @@ struct SemRelease {
 }
 
 impl SemRelease : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         self.sem.release();
     }
 }
@@ -170,7 +170,7 @@ struct SemAndSignalRelease {
 }
 
 impl SemAndSignalRelease : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         self.sem.release();
     }
 }
@@ -185,7 +185,7 @@ fn SemAndSignalRelease(sem: &r/Sem<~[mut Waitqueue]>)
 /// A mechanism for atomic-unlock-and-deschedule blocking and signalling.
 pub struct Condvar { priv sem: &Sem<~[mut Waitqueue]> }
 
-impl Condvar : Drop { fn finalize() {} }
+impl Condvar : Drop { fn finalize(&self) {} }
 
 impl &Condvar {
     /**
@@ -257,7 +257,7 @@ impl &Condvar {
         }
 
         impl SemAndSignalReacquire : Drop {
-            fn finalize() {
+            fn finalize(&self) {
                 unsafe {
                     // Needs to succeed, instead of itself dying.
                     do task::unkillable {
@@ -607,7 +607,7 @@ struct RWlockReleaseRead {
 }
 
 impl RWlockReleaseRead : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         unsafe {
             do task::unkillable {
                 let mut last_reader = false;
@@ -641,7 +641,7 @@ struct RWlockReleaseDowngrade {
 }
 
 impl RWlockReleaseDowngrade : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         unsafe {
             do task::unkillable {
                 let mut writer_or_last_reader = false;
@@ -678,10 +678,10 @@ fn RWlockReleaseDowngrade(lock: &r/RWlock) -> RWlockReleaseDowngrade/&r {
 
 /// The "write permission" token used for rwlock.write_downgrade().
 pub struct RWlockWriteMode { /* priv */ lock: &RWlock }
-impl RWlockWriteMode : Drop { fn finalize() {} }
+impl RWlockWriteMode : Drop { fn finalize(&self) {} }
 /// The "read permission" token used for rwlock.write_downgrade().
 pub struct RWlockReadMode  { priv lock: &RWlock }
-impl RWlockReadMode : Drop { fn finalize() {} }
+impl RWlockReadMode : Drop { fn finalize(&self) {} }
 
 impl &RWlockWriteMode {
     /// Access the pre-downgrade rwlock in write mode.
@@ -993,7 +993,7 @@ mod tests {
         }
 
         impl SendOnFailure : Drop {
-            fn finalize() {
+            fn finalize(&self) {
                 self.c.send(());
             }
         }

src/test/auxiliary/issue-2526.rs

@@ -12,7 +12,7 @@ struct arc_destruct<T:Const> {
 }
 
 impl<T:Const> arc_destruct<T> : Drop {
-    fn finalize() {}
+    fn finalize(&self) {}
 }
 
 fn arc_destruct<T: Const>(data: int) -> arc_destruct<T> {
@@ -34,7 +34,7 @@ struct context_res {
 }
 
 impl context_res : Drop {
-    fn finalize() {}
+    fn finalize(&self) {}
 }
 
 fn context_res() -> context_res {

src/test/auxiliary/issue-3012-1.rs

@@ -12,7 +12,7 @@ struct socket_handle {
 }
 
 impl socket_handle : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         /* c::close(self.sockfd); */
     }
 }

src/test/auxiliary/issue2170lib.rs

@@ -8,7 +8,7 @@ struct rsrc {
 }
 
 impl rsrc : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         foo(self.x);
     }
 }

src/test/auxiliary/test_comm.rs

@@ -32,7 +32,7 @@ struct port_ptr<T:Send> {
 }
 
 impl<T:Send> port_ptr<T> : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         unsafe {
             debug!("in the port_ptr destructor");
                do task::unkillable {

src/test/bench/task-perf-alloc-unwind.rs

@@ -45,7 +45,7 @@ struct r {
 }
 
 impl r : Drop {
-    fn finalize() {}
+    fn finalize(&self) {}
 }
 
 fn r(l: @nillist) -> r {

src/test/compile-fail/bind-by-move-neither-can-live-while-the-other-survives-1.rs

@@ -1,7 +1,7 @@
 struct X { x: () }
 
 impl X : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         error!("destructor runs");
     }
 }

src/test/compile-fail/bind-by-move-neither-can-live-while-the-other-survives-2.rs

@@ -1,7 +1,7 @@
 struct X { x: (), }
 
 impl X : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         error!("destructor runs");
     }
 }

src/test/compile-fail/bind-by-move-neither-can-live-while-the-other-survives-3.rs

@@ -1,7 +1,7 @@
 struct X { x: (), }
 
 impl X : Drop {
-    fn finalize() {
+    fn finalize(&self) {
         error!("destructor runs");
     }
 }