auto merge of #11294 : alexcrichton/rust/native-timer, r=brson

Commit messages have the fun details

Closes #10925

2 files changed, 94 insertions, 0 deletions

diff --git a/src/libstd/rt/at_exit_imp.rs b/src/libstd/rt/at_exit_imp.rs
new file mode 100644
index 00000000000..6f9be64a73d
--- /dev/null
+++ b/src/libstd/rt/at_exit_imp.rs
@@ -0,0 +1,72 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Implementation of running at_exit routines
+//!
+//! Documentation can be found on the `rt::at_exit` function.
+
+use cast;
+use iter::Iterator;
+use option::{Some, None};
+use ptr::RawPtr;
+use unstable::sync::Exclusive;
+use util;
+use vec::OwnedVector;
+
+type Queue = Exclusive<~[proc()]>;
+
+// You'll note that these variables are *not* atomic, and this is done on
+// purpose. This module is designed to have init() called *once* in a
+// single-task context, and then run() is called only once in another
+// single-task context. As a result of this, only the `push` function is
+// thread-safe, and it assumes that the `init` function has run previously.
+static mut QUEUE: *mut Queue = 0 as *mut Queue;
+static mut RUNNING: bool = false;
+
+pub fn init() {
+    unsafe {
+        rtassert!(!RUNNING);
+        rtassert!(QUEUE.is_null());
+        let state: ~Queue = ~Exclusive::new(~[]);
+        QUEUE = cast::transmute(state);
+    }
+}
+
+pub fn push(f: proc()) {
+    unsafe {
+        rtassert!(!RUNNING);
+        rtassert!(!QUEUE.is_null());
+        let state: &mut Queue = cast::transmute(QUEUE);
+        let mut f = Some(f);
+        state.with(|arr|  {
+            arr.push(f.take_unwrap());
+        });
+    }
+}
+
+pub fn run() {
+    let vec = unsafe {
+        rtassert!(!RUNNING);
+        rtassert!(!QUEUE.is_null());
+        RUNNING = true;
+        let state: ~Queue = cast::transmute(QUEUE);
+        QUEUE = 0 as *mut Queue;
+        let mut vec = None;
+        state.with(|arr| {
+            vec = Some(util::replace(arr, ~[]));
+        });
+        vec.take_unwrap()
+    };
+
+
+    for f in vec.move_iter() {
+        f();
+    }
+}
diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index 40e9a3ec5b2..7aa966802f2 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -127,6 +127,9 @@ mod util;
 // Global command line argument storage
 pub mod args;
 
+// Support for running procedures when a program has exited.
+mod at_exit_imp;
+
 /// The default error code of the rust runtime if the main task fails instead
 /// of exiting cleanly.
 pub static DEFAULT_ERROR_CODE: int = 101;
@@ -171,9 +174,27 @@ pub fn init(argc: int, argv: **u8) {
         env::init();
         logging::init();
         local_ptr::init();
+        at_exit_imp::init();
     }
 }
 
+/// Enqueues a procedure to run when the runtime is cleaned up
+///
+/// The procedure passed to this function will be executed as part of the
+/// runtime cleanup phase. For normal rust programs, this means that it will run
+/// after all other tasks have exited.
+///
+/// The procedure is *not* executed with a local `Task` available to it, so
+/// primitives like logging, I/O, channels, spawning, etc, are *not* available.
+/// This is meant for "bare bones" usage to clean up runtime details, this is
+/// not meant as a general-purpose "let's clean everything up" function.
+///
+/// It is forbidden for procedures to register more `at_exit` handlers when they
+/// are running, and doing so will lead to a process abort.
+pub fn at_exit(f: proc()) {
+    at_exit_imp::push(f);
+}
+
 /// One-time runtime cleanup.
 ///
 /// This function is unsafe because it performs no checks to ensure that the
@@ -184,6 +205,7 @@ pub fn init(argc: int, argv: **u8) {
 /// Invoking cleanup while portions of the runtime are still in use may cause
 /// undefined behavior.
 pub unsafe fn cleanup() {
+    at_exit_imp::run();
     args::cleanup();
     local_ptr::cleanup();
 }