rust/src/libstd/cleanup.rs
2014-02-13 12:54:17 -08:00

103 lines
2.7 KiB
Rust

// Copyright 2012 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.
#[doc(hidden)];
use ptr;
use unstable::raw;
static RC_IMMORTAL : uint = 0x77777777;
/*
* Box annihilation
*
* This runs at task death to free all boxes.
*/
unsafe fn each_live_alloc(read_next_before: bool,
f: |alloc: *mut raw::Box<()>| -> bool)
-> bool {
//! Walks the internal list of allocations
use rt::local_heap;
let mut alloc = local_heap::live_allocs();
while alloc != ptr::mut_null() {
let next_before = (*alloc).next;
if !f(alloc) {
return false;
}
if read_next_before {
alloc = next_before;
} else {
alloc = (*alloc).next;
}
}
return true;
}
#[cfg(unix)]
fn debug_mem() -> bool {
// FIXME: Need to port the environment struct to newsched
false
}
#[cfg(windows)]
fn debug_mem() -> bool {
false
}
/// Destroys all managed memory (i.e. @ boxes) held by the current task.
pub unsafe fn annihilate() {
use rt::local_heap::local_free;
let mut n_total_boxes = 0u;
// Pass 1: Make all boxes immortal.
//
// In this pass, nothing gets freed, so it does not matter whether
// we read the next field before or after the callback.
each_live_alloc(true, |alloc| {
n_total_boxes += 1;
(*alloc).ref_count = RC_IMMORTAL;
true
});
// Pass 2: Drop all boxes.
//
// In this pass, unique-managed boxes may get freed, but not
// managed boxes, so we must read the `next` field *after* the
// callback, as the original value may have been freed.
each_live_alloc(false, |alloc| {
let drop_glue = (*alloc).drop_glue;
let data = &mut (*alloc).data as *mut ();
drop_glue(data as *mut u8);
true
});
// Pass 3: Free all boxes.
//
// In this pass, managed boxes may get freed (but not
// unique-managed boxes, though I think that none of those are
// left), so we must read the `next` field before, since it will
// not be valid after.
each_live_alloc(true, |alloc| {
local_free(alloc as *u8);
true
});
if debug_mem() {
// We do logging here w/o allocation.
debug!("total boxes annihilated: {}", n_total_boxes);
}
}