Made std::task::TaskBuilder::future_result() easier to use

src/libextra/arc.rs

@@ -823,7 +823,7 @@ mod tests {
         do 5.times {
             let arc3 = arc.clone();
             let mut builder = task::task();
-            builder.future_result(|r| children.push(r));
+            children.push(builder.future_result());
             do builder.spawn {
                 do arc3.read |num| {
                     assert!(*num >= 0);

src/libextra/test.rs

@@ -870,14 +870,12 @@ pub fn run_test(force_ignore: bool,
                       testfn: ~fn()) {
         let testfn_cell = ::std::cell::Cell::new(testfn);
         do task::spawn {
-            let mut result_future = None; // task::future_result(builder);
-
             let mut task = task::task();
             task.unlinked();
-            task.future_result(|r| { result_future = Some(r) });
+            let result_future = task.future_result();
             task.spawn(testfn_cell.take());
 
-            let task_result = result_future.unwrap().recv();
+            let task_result = result_future.recv();
             let test_result = calc_result(&desc,
                                           task_result == task::Success);
             monitor_ch.send((desc.clone(), test_result));

src/libstd/result.rs

@@ -463,7 +463,6 @@ mod tests {
     use str::OwnedStr;
     use vec::ImmutableVector;
     use to_str::ToStr;
-    use fmt::Default;
 
     pub fn op1() -> Result<int, ~str> { Ok(666) }
     pub fn op2() -> Result<int, ~str> { Err(~"sadface") }

src/libstd/rt/task.rs

@@ -621,29 +621,4 @@ mod test {
             a.next = Some(b);
         }
     }
-
-    // XXX: This is a copy of test_future_result in std::task.
-    // It can be removed once the scheduler is turned on by default.
-    #[test]
-    fn future_result() {
-        do run_in_newsched_task {
-            use option::{Some, None};
-            use task::*;
-
-            let mut result = None;
-            let mut builder = task();
-            builder.future_result(|r| result = Some(r));
-            do builder.spawn {}
-            assert_eq!(result.unwrap().recv(), Success);
-
-            result = None;
-            let mut builder = task();
-            builder.future_result(|r| result = Some(r));
-            builder.unlinked();
-            do builder.spawn {
-                fail2!();
-            }
-            assert_eq!(result.unwrap().recv(), Failure);
-        }
-    }
 }

src/libstd/task/mod.rs

@@ -258,24 +258,22 @@ impl TaskBuilder {
         self.opts.indestructible = true;
     }
 
-    /**
+    /// Get a future representing the exit status of the task.
-     * Get a future representing the exit status of the task.
+    ///
-     *
+    /// Taking the value of the future will block until the child task
-     * Taking the value of the future will block until the child task
+    /// terminates. The future result return value will be created *before* the task is
-     * terminates. The future-receiving callback specified will be called
+    /// spawned; as such, do not invoke .get() on it directly;
-     * *before* the task is spawned; as such, do not invoke .get() within the
+    /// rather, store it in an outer variable/list for later use.
-     * closure; rather, store it in an outer variable/list for later use.
+    ///
-     *
+    /// Note that the future returned by this function is only useful for
-     * Note that the future returning by this function is only useful for
+    /// obtaining the value of the next task to be spawning with the
-     * obtaining the value of the next task to be spawning with the
+    /// builder. If additional tasks are spawned with the same builder
-     * builder. If additional tasks are spawned with the same builder
+    /// then a new result future must be obtained prior to spawning each
-     * then a new result future must be obtained prior to spawning each
+    /// task.
-     * task.
+    ///
-     *
+    /// # Failure
-     * # Failure
+    /// Fails if a future_result was already set for this task.
-     * Fails if a future_result was already set for this task.
+    pub fn future_result(&mut self) -> Port<TaskResult> {
-     */
-    pub fn future_result(&mut self, blk: &fn(v: Port<TaskResult>)) {
         // FIXME (#3725): Once linked failure and notification are
         // handled in the library, I can imagine implementing this by just
         // registering an arbitrary number of task::on_exit handlers and
@@ -288,10 +286,10 @@ impl TaskBuilder {
         // Construct the future and give it to the caller.
         let (notify_pipe_po, notify_pipe_ch) = stream::<TaskResult>();
 
-        blk(notify_pipe_po);
-
         // Reconfigure self to use a notify channel.
         self.opts.notify_chan = Some(notify_pipe_ch);
+
+        notify_pipe_po
     }
 
     /// Name the task-to-be. Currently the name is used for identification
@@ -398,15 +396,14 @@ impl TaskBuilder {
      */
     pub fn try<T:Send>(&mut self, f: ~fn() -> T) -> Result<T,()> {
         let (po, ch) = stream::<T>();
-        let mut result = None;
 
-        self.future_result(|r| { result = Some(r); });
+        let result = self.future_result();
 
         do self.spawn {
             ch.send(f());
         }
 
-        match result.unwrap().recv() {
+        match result.recv() {
             Success => result::Ok(po.recv()),
             Failure => result::Err(())
         }
@@ -1024,27 +1021,25 @@ fn test_add_wrapper() {
 
 #[test]
 fn test_future_result() {
-    let mut result = None;
     let mut builder = task();
-    builder.future_result(|r| result = Some(r));
+    let result = builder.future_result();
     do builder.spawn {}
-    assert_eq!(result.unwrap().recv(), Success);
+    assert_eq!(result.recv(), Success);
 
-    result = None;
     let mut builder = task();
-    builder.future_result(|r| result = Some(r));
+    let result = builder.future_result();
     builder.unlinked();
     do builder.spawn {
         fail2!();
     }
-    assert_eq!(result.unwrap().recv(), Failure);
+    assert_eq!(result.recv(), Failure);
 }
 
 #[test] #[should_fail]
 fn test_back_to_the_future_result() {
     let mut builder = task();
-    builder.future_result(util::ignore);
+    builder.future_result();
-    builder.future_result(util::ignore);
+    builder.future_result();
 }
 
 #[test]

src/libstd/unstable/sync.rs

@@ -580,32 +580,29 @@ mod tests {
         // Now try the same thing, but with the child task blocking.
         let x = Exclusive::new(~~"hello");
         let x2 = Cell::new(x.clone());
-        let mut res = None;
         let mut builder = task::task();
-        builder.future_result(|r| res = Some(r));
+        let res = builder.future_result();
         do builder.spawn {
             let x2 = x2.take();
             assert!(x2.unwrap() == ~~"hello");
         }
         // Have to get rid of our reference before blocking.
         util::ignore(x);
-        res.unwrap().recv();
+        res.recv();
     }
 
     #[test] #[should_fail]
     fn exclusive_new_unwrap_conflict() {
         let x = Exclusive::new(~~"hello");
         let x2 = Cell::new(x.clone());
-        let mut res = None;
         let mut builder = task::task();
-        builder.future_result(|r| res = Some(r));
+        let res = builder.future_result();
         do builder.spawn {
             let x2 = x2.take();
             assert!(x2.unwrap() == ~~"hello");
         }
         assert!(x.unwrap() == ~~"hello");
-        // See #4689 for why this can't be just "res.recv()".
+        assert!(res.recv() == task::Success);
-        assert!(res.unwrap().recv() == task::Success);
     }
 
     #[test]

src/test/bench/msgsend-pipes-shared.rs

@@ -67,7 +67,7 @@ fn run(args: &[~str]) {
     for _ in range(0u, workers) {
         let to_child = to_child.clone();
         let mut builder = task::task();
-        builder.future_result(|r| worker_results.push(r));
+        worker_results.push(builder.future_result());
         do builder.spawn {
             for _ in range(0u, size / workers) {
                 //error2!("worker {:?}: sending {:?} bytes", i, num_bytes);

src/test/bench/msgsend-pipes.rs

@@ -61,7 +61,7 @@ fn run(args: &[~str]) {
     for _ in range(0u, workers) {
         let to_child = to_child.clone();
         let mut builder = task::task();
-        builder.future_result(|r| worker_results.push(r));
+        worker_results.push(builder.future_result());
         do builder.spawn {
             for _ in range(0u, size / workers) {
                 //error2!("worker {:?}: sending {:?} bytes", i, num_bytes);

src/test/bench/shootout-pfib.rs

@@ -84,7 +84,7 @@ fn stress(num_tasks: int) {
     let mut results = ~[];
     for i in range(0, num_tasks) {
         let mut builder = task::task();
-        builder.future_result(|r| results.push(r));
+        results.push(builder.future_result());
         do builder.spawn {
             stress_task(i);
         }

src/test/bench/task-perf-linked-failure.rs

@@ -54,13 +54,12 @@ fn grandchild_group(num_tasks: uint) {
 }
 
 fn spawn_supervised_blocking(myname: &str, f: ~fn()) {
-    let mut res = None;
     let mut builder = task::task();
-    builder.future_result(|r| res = Some(r));
+    let res = builder.future_result();
     builder.supervised();
     builder.spawn(f);
     error2!("{} group waiting", myname);
-    let x = res.unwrap().recv();
+    let x = res.recv();
     assert_eq!(x, task::Success);
 }
 

src/test/run-pass/task-comm-12.rs

@@ -18,9 +18,8 @@ fn start(_task_number: int) { info2!("Started / Finished task."); }
 
 fn test00() {
     let i: int = 0;
-    let mut result = None;
     let mut builder = task::task();
-    builder.future_result(|r| result = Some(r));
+    let result = builder.future_result();
     do builder.spawn {
         start(i)
     }
@@ -33,7 +32,7 @@ fn test00() {
     }
 
     // Try joining tasks that have already finished.
-    result.unwrap().recv();
+    result.recv();
 
     info2!("Joined task.");
 }

src/test/run-pass/task-comm-3.rs

@@ -45,7 +45,7 @@ fn test00() {
     while i < number_of_tasks {
         let ch = ch.clone();
         let mut builder = task::task();
-        builder.future_result(|r| results.push(r));
+        results.push(builder.future_result());
         builder.spawn({
             let i = i;
             || test00_start(&ch, i, number_of_messages)

src/test/run-pass/task-comm-9.rs

@@ -28,9 +28,8 @@ fn test00() {
     let (p, ch) = comm::stream();
     let number_of_messages: int = 10;
 
-    let mut result = None;
     let mut builder = task::task();
-    builder.future_result(|r| result = Some(r));
+    let result = builder.future_result();
     do builder.spawn {
         test00_start(&ch, number_of_messages);
     }
@@ -42,7 +41,7 @@ fn test00() {
         i += 1;
     }
 
-    result.unwrap().recv();
+    result.recv();
 
     assert_eq!(sum, number_of_messages * (number_of_messages - 1) / 2);
 }

src/test/run-pass/yield.rs

@@ -12,16 +12,15 @@
 use std::task;
 
 pub fn main() {
-    let mut result = None;
     let mut builder = task::task();
-    builder.future_result(|r| { result = Some(r); });
+    let result = builder.future_result();
     builder.spawn(child);
     error2!("1");
     task::deschedule();
     error2!("2");
     task::deschedule();
     error2!("3");
-    result.unwrap().recv();
+    result.recv();
 }
 
 fn child() {

src/test/run-pass/yield1.rs

@@ -12,13 +12,12 @@
 use std::task;
 
 pub fn main() {
-    let mut result = None;
     let mut builder = task::task();
-    builder.future_result(|r| { result = Some(r); });
+    let result = builder.future_result();
     builder.spawn(child);
     error2!("1");
     task::deschedule();
-    result.unwrap().recv();
+    result.recv();
 }
 
 fn child() { error2!("2"); }