Make rekillable consistent with unkillable

As for now, rekillable is an unsafe function, instead, it should behave
just like unkillable by encapsulating unsafe code within an unsafe
block.

This patch does that and removes unsafe blocks that were encapsulating
rekillable calls throughout rust's libs.

Fixes #8232

1 files changed, 27 insertions, 16 deletions

diff --git a/src/libstd/task/mod.rs b/src/libstd/task/mod.rs
index e76b81a904d..bac4991d858 100644
--- a/src/libstd/task/mod.rs
+++ b/src/libstd/task/mod.rs
@@ -597,21 +597,34 @@ pub fn unkillable<U>(f: &fn() -> U) -> U {
     }
 }
 
-/// The inverse of unkillable. Only ever to be used nested in unkillable().
-pub unsafe fn rekillable<U>(f: &fn() -> U) -> U {
+/**
+ * Makes killable a task marked as unkillable
+ *
+ * # Example
+ *
+ * ~~~
+ * do task::unkillable {
+ *     do task::rekillable {
+ *          // Task is killable
+ *     }
+ * }
+ */
+pub fn rekillable<U>(f: &fn() -> U) -> U {
     use rt::task::Task;
 
-    if in_green_task_context() {
-        let t = Local::unsafe_borrow::<Task>();
-        do (|| {
-            (*t).death.allow_kill((*t).unwinder.unwinding);
+    unsafe {
+        if in_green_task_context() {
+            let t = Local::unsafe_borrow::<Task>();
+            do (|| {
+                (*t).death.allow_kill((*t).unwinder.unwinding);
+                f()
+            }).finally {
+                (*t).death.inhibit_kill((*t).unwinder.unwinding);
+            }
+        } else {
+            // FIXME(#3095): As in unkillable().
             f()
-        }).finally {
-            (*t).death.inhibit_kill((*t).unwinder.unwinding);
         }
-    } else {
-        // FIXME(#3095): As in unkillable().
-        f()
     }
 }
 
@@ -646,11 +659,9 @@ fn test_kill_rekillable_task() {
     do run_in_newsched_task {
         do task::try {
             do task::unkillable {
-                unsafe {
-                    do task::rekillable {
-                        do task::spawn {
-                            fail!();
-                        }
+                do task::rekillable {
+                    do task::spawn {
+                        fail!();
                     }
                 }
             }