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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /mozglue/misc/ConditionVariable_posix.cpp | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | mozglue/misc/ConditionVariable_posix.cpp | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/mozglue/misc/ConditionVariable_posix.cpp b/mozglue/misc/ConditionVariable_posix.cpp new file mode 100644 index 0000000000..5c98560551 --- /dev/null +++ b/mozglue/misc/ConditionVariable_posix.cpp @@ -0,0 +1,159 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "mozilla/Assertions.h" +#include "mozilla/CheckedInt.h" + +#include <errno.h> +#include <pthread.h> +#include <time.h> + +#include "mozilla/PlatformConditionVariable.h" +#include "mozilla/PlatformMutex.h" +#include "MutexPlatformData_posix.h" + +using mozilla::CheckedInt; +using mozilla::TimeDuration; + +static const long NanoSecPerSec = 1000000000; + +// Android 4.4 or earlier & macOS 10.12 has the clock functions, but not +// pthread_condattr_setclock. +#if defined(HAVE_CLOCK_MONOTONIC) && \ + !(defined(__ANDROID__) && __ANDROID_API__ < 21) && !defined(__APPLE__) +# define CV_USE_CLOCK_API +#endif + +#ifdef CV_USE_CLOCK_API +// The C++ specification defines std::condition_variable::wait_for in terms of +// std::chrono::steady_clock, which is closest to CLOCK_MONOTONIC. +static const clockid_t WhichClock = CLOCK_MONOTONIC; + +// While timevaladd is widely available to work with timevals, the newer +// timespec structure is largely lacking such conveniences. Thankfully, the +// utilities available in MFBT make implementing our own quite easy. +static void moz_timespecadd(struct timespec* lhs, struct timespec* rhs, + struct timespec* result) { + // Add nanoseconds. This may wrap, but not above 2 billion. + MOZ_RELEASE_ASSERT(lhs->tv_nsec < NanoSecPerSec); + MOZ_RELEASE_ASSERT(rhs->tv_nsec < NanoSecPerSec); + result->tv_nsec = lhs->tv_nsec + rhs->tv_nsec; + + // Add seconds, checking for overflow in the platform specific time_t type. + CheckedInt<time_t> sec = CheckedInt<time_t>(lhs->tv_sec) + rhs->tv_sec; + + // If nanoseconds overflowed, carry the result over into seconds. + if (result->tv_nsec >= NanoSecPerSec) { + MOZ_RELEASE_ASSERT(result->tv_nsec < 2 * NanoSecPerSec); + result->tv_nsec -= NanoSecPerSec; + sec += 1; + } + + // Extracting the value asserts that there was no overflow. + MOZ_RELEASE_ASSERT(sec.isValid()); + result->tv_sec = sec.value(); +} +#endif + +struct mozilla::detail::ConditionVariableImpl::PlatformData { + pthread_cond_t ptCond; +}; + +mozilla::detail::ConditionVariableImpl::ConditionVariableImpl() { + pthread_cond_t* ptCond = &platformData()->ptCond; + +#ifdef CV_USE_CLOCK_API + pthread_condattr_t attr; + int r0 = pthread_condattr_init(&attr); + MOZ_RELEASE_ASSERT(!r0); + + int r1 = pthread_condattr_setclock(&attr, WhichClock); + MOZ_RELEASE_ASSERT(!r1); + + int r2 = pthread_cond_init(ptCond, &attr); + MOZ_RELEASE_ASSERT(!r2); + + int r3 = pthread_condattr_destroy(&attr); + MOZ_RELEASE_ASSERT(!r3); +#else + int r = pthread_cond_init(ptCond, NULL); + MOZ_RELEASE_ASSERT(!r); +#endif +} + +mozilla::detail::ConditionVariableImpl::~ConditionVariableImpl() { + int r = pthread_cond_destroy(&platformData()->ptCond); + MOZ_RELEASE_ASSERT(r == 0); +} + +void mozilla::detail::ConditionVariableImpl::notify_one() { + int r = pthread_cond_signal(&platformData()->ptCond); + MOZ_RELEASE_ASSERT(r == 0); +} + +void mozilla::detail::ConditionVariableImpl::notify_all() { + int r = pthread_cond_broadcast(&platformData()->ptCond); + MOZ_RELEASE_ASSERT(r == 0); +} + +void mozilla::detail::ConditionVariableImpl::wait(MutexImpl& lock) { + pthread_cond_t* ptCond = &platformData()->ptCond; + pthread_mutex_t* ptMutex = &lock.platformData()->ptMutex; + + int r = pthread_cond_wait(ptCond, ptMutex); + MOZ_RELEASE_ASSERT(r == 0); +} + +mozilla::CVStatus mozilla::detail::ConditionVariableImpl::wait_for( + MutexImpl& lock, const TimeDuration& a_rel_time) { + if (a_rel_time == TimeDuration::Forever()) { + wait(lock); + return CVStatus::NoTimeout; + } + + pthread_cond_t* ptCond = &platformData()->ptCond; + pthread_mutex_t* ptMutex = &lock.platformData()->ptMutex; + int r; + + // Clamp to 0, as time_t is unsigned. + TimeDuration rel_time = a_rel_time < TimeDuration::FromSeconds(0) + ? TimeDuration::FromSeconds(0) + : a_rel_time; + + // Convert the duration to a timespec. + struct timespec rel_ts; + rel_ts.tv_sec = static_cast<time_t>(rel_time.ToSeconds()); + rel_ts.tv_nsec = + static_cast<uint64_t>(rel_time.ToMicroseconds() * 1000.0) % NanoSecPerSec; + +#ifdef CV_USE_CLOCK_API + struct timespec now_ts; + r = clock_gettime(WhichClock, &now_ts); + MOZ_RELEASE_ASSERT(!r); + + struct timespec abs_ts; + moz_timespecadd(&now_ts, &rel_ts, &abs_ts); + + r = pthread_cond_timedwait(ptCond, ptMutex, &abs_ts); +#else + // Our non-clock-supporting platforms, OS X and Android, do support waiting + // on a condition variable with a relative timeout. + r = pthread_cond_timedwait_relative_np(ptCond, ptMutex, &rel_ts); +#endif + + if (r == 0) { + return CVStatus::NoTimeout; + } + MOZ_RELEASE_ASSERT(r == ETIMEDOUT); + return CVStatus::Timeout; +} + +mozilla::detail::ConditionVariableImpl::PlatformData* +mozilla::detail::ConditionVariableImpl::platformData() { + static_assert(sizeof platformData_ >= sizeof(PlatformData), + "platformData_ is too small"); + return reinterpret_cast<PlatformData*>(platformData_); +} |