Handle notification channels in task.rs

Author: bblum

src/libcore/task.rs

@@ -612,18 +612,23 @@ class taskgroup {
     // Lists of tasks who will kill us if they fail, but whom we won't kill.
     let parents:    option<(taskgroup_arc,uint)>;
     let is_main:    bool;
+    let notifier:   option<auto_notify>;
     new(me: *rust_task, -tasks: taskgroup_arc, my_pos: uint,
-        -parents: option<(taskgroup_arc,uint)>, is_main: bool) {
-        self.me      = me;
-        self.tasks   = tasks;
-        self.my_pos  = my_pos;
-        self.parents = parents;
-        self.is_main = is_main;
+        -parents: option<(taskgroup_arc,uint)>, is_main: bool,
+        -notifier: option<auto_notify>) {
+        self.me       = me;
+        self.tasks    = tasks;
+        self.my_pos   = my_pos;
+        self.parents  = parents;
+        self.is_main  = is_main;
+        self.notifier = notifier;
+        self.notifier.iter(|x| { x.failed = false; });
     }
     // Runs on task exit.
     drop {
         // If we are failing, the whole taskgroup needs to die.
         if rustrt::rust_task_is_unwinding(self.me) {
+            self.notifier.iter(|x| { x.failed = true; });
             // Take everybody down with us.
             kill_taskgroup(self.tasks, self.me, self.my_pos, self.is_main);
         } else {
@@ -641,6 +646,19 @@ class taskgroup {
     }
 }
 
+class auto_notify {
+    let notify_chan: comm::chan<notification>;
+    let mut failed:  bool;
+    new(chan: comm::chan<notification>) {
+        self.notify_chan = chan;
+        self.failed = true; // Un-set above when taskgroup successfully made.
+    }
+    drop {
+        let result = if self.failed { failure } else { success };
+        comm::send(self.notify_chan, exit(get_task(), result));
+    }
+}
+
 fn enlist_in_taskgroup(group_arc: taskgroup_arc,
                        me: *rust_task) -> option<uint> {
     do group_arc.with |_c, state| {
@@ -750,7 +768,7 @@ fn share_spawner_taskgroup(linked: bool)
             let tasks = arc::exclusive(some((dvec::from_elem(some(me)),
                                              dvec::dvec())));
             // Main group has no parent group.
-            let group = @taskgroup(me, tasks.clone(), 0, none, true);
+            let group = @taskgroup(me, tasks.clone(), 0, none, true, none);
             unsafe { local_set(me, taskgroup_key(), group); }
             // Tell child task it's also in the main group.
             // Whether or not it wanted our parent group, we haven't got one.
@@ -796,15 +814,11 @@ fn spawn_raw(opts: task_opts, +f: fn~()) {
             // Getting killed after here would leak the task.
 
             let child_wrapper =
-                make_child_wrapper(new_task, child_tg, parent_tg, is_main, f);
+                make_child_wrapper(new_task, child_tg, parent_tg, is_main,
+                                   opts.notify_chan, f);
             let fptr = ptr::addr_of(child_wrapper);
             let closure: *rust_closure = unsafe::reinterpret_cast(fptr);
 
-            do option::iter(opts.notify_chan) |c| {
-                // FIXME (#1087): Would like to do notification in Rust
-                rustrt::rust_task_config_notify(new_task, c);
-            }
-
             // Getting killed between these two calls would free the child's
             // closure. (Reordering them wouldn't help - then getting killed
             // between them would leak.)
@@ -829,6 +843,7 @@ fn spawn_raw(opts: task_opts, +f: fn~()) {
     //     }
     fn make_child_wrapper(child: *rust_task, -child_tg: taskgroup_arc,
                           -parent_tg: option<taskgroup_arc>, is_main: bool,
+                          notify_chan: option<comm::chan<notification>>,
                           -f: fn~()) -> fn~() {
         let child_tg_ptr = ~mut some((child_tg, parent_tg));
         fn~() {
@@ -837,6 +852,11 @@ fn spawn_raw(opts: task_opts, +f: fn~()) {
             *child_tg_ptr <-> tg_data_opt;
             let (child_tg, parent_tg) = option::unwrap(tg_data_opt);
             // Child task runs this code.
+
+            // Even if the below code fails to kick the child off, we must
+            // send something on the notify channel.
+            let notifier = notify_chan.map(|c| auto_notify(c));
+
             // Set up membership in taskgroup. If this returns none, some
             // task was already failing, so don't bother doing anything.
             alt enlist_in_taskgroup(child_tg, child) {
@@ -862,7 +882,7 @@ fn spawn_raw(opts: task_opts, +f: fn~()) {
                     };
                     if enlist_ok {
                         let group = @taskgroup(child, child_tg, my_pos,
-                                               pg, is_main);
+                                               pg, is_main, notifier);
                         unsafe { local_set(child, taskgroup_key(), group); }
                         // Run the child's body.
                         f();
@@ -1129,9 +1149,6 @@ extern mod rustrt {
     fn new_task() -> *rust_task;
     fn rust_new_task_in_sched(id: sched_id) -> *rust_task;
 
-    fn rust_task_config_notify(
-        task: *rust_task, &&chan: comm::chan<notification>);
-
     fn start_task(task: *rust_task, closure: *rust_closure);
 
     fn rust_task_is_unwinding(task: *rust_task) -> bool;