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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /library/std/src/sys/itron/wait_flag.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/std/src/sys/itron/wait_flag.rs')
-rw-r--r-- | library/std/src/sys/itron/wait_flag.rs | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/library/std/src/sys/itron/wait_flag.rs b/library/std/src/sys/itron/wait_flag.rs new file mode 100644 index 000000000..e432edd20 --- /dev/null +++ b/library/std/src/sys/itron/wait_flag.rs @@ -0,0 +1,72 @@ +use crate::mem::MaybeUninit; +use crate::time::Duration; + +use super::{ + abi, + error::{expect_success, fail}, + time::with_tmos, +}; + +const CLEAR: abi::FLGPTN = 0; +const RAISED: abi::FLGPTN = 1; + +/// A thread parking primitive that is not susceptible to race conditions, +/// but provides no atomic ordering guarantees and allows only one `raise` per wait. +pub struct WaitFlag { + flag: abi::ID, +} + +impl WaitFlag { + /// Creates a new wait flag. + pub fn new() -> WaitFlag { + let flag = expect_success( + unsafe { + abi::acre_flg(&abi::T_CFLG { + flgatr: abi::TA_FIFO | abi::TA_WSGL | abi::TA_CLR, + iflgptn: CLEAR, + }) + }, + &"acre_flg", + ); + + WaitFlag { flag } + } + + /// Wait for the wait flag to be raised. + pub fn wait(&self) { + let mut token = MaybeUninit::uninit(); + expect_success( + unsafe { abi::wai_flg(self.flag, RAISED, abi::TWF_ORW, token.as_mut_ptr()) }, + &"wai_flg", + ); + } + + /// Wait for the wait flag to be raised or the timeout to occur. + /// + /// Returns whether the flag was raised (`true`) or the operation timed out (`false`). + pub fn wait_timeout(&self, dur: Duration) -> bool { + let mut token = MaybeUninit::uninit(); + let res = with_tmos(dur, |tmout| unsafe { + abi::twai_flg(self.flag, RAISED, abi::TWF_ORW, token.as_mut_ptr(), tmout) + }); + + match res { + abi::E_OK => true, + abi::E_TMOUT => false, + error => fail(error, &"twai_flg"), + } + } + + /// Raise the wait flag. + /// + /// Calls to this function should be balanced with the number of successful waits. + pub fn raise(&self) { + expect_success(unsafe { abi::set_flg(self.flag, RAISED) }, &"set_flg"); + } +} + +impl Drop for WaitFlag { + fn drop(&mut self) { + expect_success(unsafe { abi::del_flg(self.flag) }, &"del_flg"); + } +} |