Remove old comm-based weak task interface

Author: brson

src/libcore/private.rs

@@ -39,8 +39,6 @@ pub mod weak_task;
 
 extern mod rustrt {
     #[legacy_exports];
-    unsafe fn rust_task_weaken(ch: rust_port_id);
-    unsafe fn rust_task_unweaken(ch: rust_port_id);
 
     unsafe fn rust_create_little_lock() -> rust_little_lock;
     unsafe fn rust_destroy_little_lock(lock: rust_little_lock);
@@ -92,111 +90,11 @@ fn test_run_in_bare_thread() unsafe {
     }
 }
 
-#[allow(non_camel_case_types)] // runtime type
-type rust_port_id = uint;
-
 fn compare_and_swap(address: &mut int, oldval: int, newval: int) -> bool {
     let old = rusti::atomic_cxchg(address, oldval, newval);
     old == oldval
 }
 
-/**
- * Convert the current task to a 'weak' task temporarily
- *
- * As a weak task it will not be counted towards the runtime's set
- * of live tasks. When there are no more outstanding live (non-weak) tasks
- * the runtime will send an exit message on the provided channel.
- *
- * This function is super-unsafe. Do not use.
- *
- * # Safety notes
- *
- * * Weak tasks must either die on their own or exit upon receipt of
- *   the exit message. Failure to do so will cause the runtime to never
- *   exit
- * * Tasks must not call `weaken_task` multiple times. This will
- *   break the kernel's accounting of live tasks.
- * * Weak tasks must not be supervised. A supervised task keeps
- *   a reference to its parent, so the parent will not die.
- */
-pub unsafe fn weaken_task(f: fn(oldcomm::Port<()>)) {
-    let po = oldcomm::Port();
-    let ch = oldcomm::Chan(&po);
-    unsafe {
-        rustrt::rust_task_weaken(cast::reinterpret_cast(&ch));
-    }
-    let _unweaken = Unweaken(ch);
-    f(po);
-
-    struct Unweaken {
-      ch: oldcomm::Chan<()>,
-      drop unsafe {
-        rustrt::rust_task_unweaken(cast::reinterpret_cast(&self.ch));
-      }
-    }
-
-    fn Unweaken(ch: oldcomm::Chan<()>) -> Unweaken {
-        Unweaken {
-            ch: ch
-        }
-    }
-}
-
-#[test]
-pub fn test_weaken_task_then_unweaken() {
-    do task::try {
-        unsafe {
-            do weaken_task |_po| {
-            }
-        }
-    };
-}
-
-#[test]
-pub fn test_weaken_task_wait() {
-    do task::spawn_unlinked {
-        unsafe {
-            do weaken_task |po| {
-                oldcomm::recv(po);
-            }
-        }
-    }
-}
-
-#[test]
-pub fn test_weaken_task_stress() {
-    // Create a bunch of weak tasks
-    for iter::repeat(100u) {
-        do task::spawn {
-            unsafe {
-                do weaken_task |_po| {
-                }
-            }
-        }
-        do task::spawn_unlinked {
-            unsafe {
-                do weaken_task |po| {
-                    // Wait for it to tell us to die
-                    oldcomm::recv(po);
-                }
-            }
-        }
-    }
-}
-
-#[test]
-#[ignore(cfg(windows))]
-pub fn test_weaken_task_fail() {
-    let res = do task::try {
-        unsafe {
-            do weaken_task |_po| {
-                fail;
-            }
-        }
-    };
-    assert result::is_err(&res);
-}
-
 /****************************************************************************
  * Shared state & exclusive ARC
  ****************************************************************************/

src/rt/rust_builtin.cpp

@@ -858,18 +858,6 @@ rust_compare_and_swap_ptr(intptr_t *address,
     return sync::compare_and_swap(address, oldval, newval);
 }
 
-extern "C" CDECL void
-rust_task_weaken(rust_port_id chan) {
-    rust_task *task = rust_get_current_task();
-    task->kernel->weaken_task(chan);
-}
-
-extern "C" CDECL void
-rust_task_unweaken(rust_port_id chan) {
-    rust_task *task = rust_get_current_task();
-    task->kernel->unweaken_task(chan);
-}
-
 extern "C" void
 rust_task_inhibit_kill(rust_task *task) {
     task->inhibit_kill();

src/rt/rust_kernel.cpp

@@ -368,30 +368,6 @@ rust_kernel::unregister_task() {
     }
 }
 
-void
-rust_kernel::weaken_task(rust_port_id chan) {
-    {
-        scoped_lock with(weak_task_lock);
-        KLOG_("Weakening task with channel %" PRIdPTR, chan);
-        weak_task_chans.push_back(chan);
-    }
-    inc_weak_task_count();
-}
-
-void
-rust_kernel::unweaken_task(rust_port_id chan) {
-    dec_weak_task_count();
-    {
-        scoped_lock with(weak_task_lock);
-        KLOG_("Unweakening task with channel %" PRIdPTR, chan);
-        std::vector<rust_port_id>::iterator iter =
-            std::find(weak_task_chans.begin(), weak_task_chans.end(), chan);
-        if (iter != weak_task_chans.end()) {
-            weak_task_chans.erase(iter);
-        }
-    }
-}
-
 void
 rust_kernel::inc_weak_task_count() {
     uintptr_t new_non_weak_tasks = sync::decrement(non_weak_tasks);
@@ -407,23 +383,6 @@ rust_kernel::dec_weak_task_count() {
     KLOG_("New non-weak tasks %" PRIdPTR, new_non_weak_tasks);
 }
 
-void
-rust_kernel::end_weak_tasks() {
-    std::vector<rust_port_id> chancopies;
-    {
-        scoped_lock with(weak_task_lock);
-        chancopies = weak_task_chans;
-        weak_task_chans.clear();
-    }
-    while (!chancopies.empty()) {
-        rust_port_id chan = chancopies.back();
-        chancopies.pop_back();
-        KLOG_("Notifying weak task " PRIdPTR, chan);
-        uintptr_t token = 0;
-        send_to_port(chan, &token);
-    }
-}
-
 void
 rust_kernel::begin_shutdown() {
     {
@@ -439,7 +398,6 @@ rust_kernel::begin_shutdown() {
 
     run_exit_functions();
     allow_scheduler_exit();
-    end_weak_tasks();
 }
 
 bool

src/rt/rust_kernel.h

@@ -119,14 +119,9 @@ class rust_kernel {
 
     // An atomically updated count of the live, 'non-weak' tasks
     uintptr_t non_weak_tasks;
-    // Protects weak_task_chans
-    lock_and_signal weak_task_lock;
-    // A list of weak tasks that need to be told when to exit
-    std::vector<rust_port_id> weak_task_chans;
 
     rust_scheduler* get_scheduler_by_id_nolock(rust_sched_id id);
     void allow_scheduler_exit();
-    void end_weak_tasks();
     void begin_shutdown();
 
     lock_and_signal at_exit_lock;
@@ -180,8 +175,6 @@ class rust_kernel {
 
     void register_task();
     void unregister_task();
-    void weaken_task(rust_port_id chan);
-    void unweaken_task(rust_port_id chan);
     void inc_weak_task_count();
     void dec_weak_task_count();
 

src/rt/rustrt.def.in

@@ -61,8 +61,6 @@ rust_task_yield
 rust_task_is_unwinding
 rust_get_task
 rust_get_stack_segment
-rust_task_weaken
-rust_task_unweaken
 rust_log_str
 start_task
 vec_reserve_shared_actual