64 lines
2.1 KiB
Rust
64 lines
2.1 KiB
Rust
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// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Access to a single thread-local pointer
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use libc::c_void;
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use cast;
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use option::{Option, Some, None};
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use tls = rt::thread_local_storage;
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/// Initialize the TLS key. Other ops will fail if this isn't executed first.
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pub fn init_tls_key() {
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unsafe {
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rust_initialize_rt_tls_key();
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extern {
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fn rust_initialize_rt_tls_key();
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}
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}
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}
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pub fn tls_key() -> tls::Key {
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match maybe_tls_key() {
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Some(key) => key,
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None => abort!("runtime tls key not initialized")
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}
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}
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pub fn maybe_tls_key() -> Option<tls::Key> {
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unsafe {
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let key: *mut c_void = rust_get_rt_tls_key();
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let key: &mut tls::Key = cast::transmute(key);
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let key = *key;
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// Check that the key has been initialized.
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// NB: This is a little racy because, while the key is
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// initalized under a mutex and it's assumed to be initalized
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// in the Scheduler ctor by any thread that needs to use it,
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// we are not accessing the key under a mutex. Threads that
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// are not using the new Scheduler but still *want to check*
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// whether they are running under a new Scheduler may see a 0
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// value here that is in the process of being initialized in
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// another thread. I think this is fine since the only action
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// they could take if it was initialized would be to check the
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// thread-local value and see that it's not set.
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if key != -1 {
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return Some(key);
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} else {
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return None;
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}
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}
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}
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extern {
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#[fast_ffi]
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fn rust_get_rt_tls_key() -> *mut c_void;
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}
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