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authorColin Cross <ccross@android.com>2022-04-13 03:15:00 +0000
committerAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>2022-04-13 03:15:00 +0000
commit6c9587948173932b64d97c288a947e43d2a2ac14 (patch)
tree2ce94d7f0804ccb77d1fa9b2a1bca00eecdff1e2 /third_party/abseil-cpp/absl/synchronization/internal/futex.h
parentf60eaea2240ba9e1c508e8e0c91d39ee9fc47be5 (diff)
parent43d8f56cdc20240b37c36bf417dd0d6999bce738 (diff)
downloadwebrtc-6c9587948173932b64d97c288a947e43d2a2ac14.tar.gz
Merge changes I0ab600cd,I1e74c64a am: 798f3afdf6 am: 2f9c4b2c3b am: a9167328fc am: 7563023510 am: 43d8f56cdcandroid-13.0.0_r83android-13.0.0_r82android-13.0.0_r81android-13.0.0_r80android-13.0.0_r79android-13.0.0_r78android-13.0.0_r77android-13.0.0_r76android-13.0.0_r75android-13.0.0_r74android-13.0.0_r73android-13.0.0_r72android-13.0.0_r71android-13.0.0_r70android-13.0.0_r69android-13.0.0_r68android-13.0.0_r67android-13.0.0_r66android-13.0.0_r65android-13.0.0_r64android-13.0.0_r63android-13.0.0_r62android-13.0.0_r61android-13.0.0_r60android-13.0.0_r59android-13.0.0_r58android-13.0.0_r56android-13.0.0_r54android-13.0.0_r53android-13.0.0_r52android-13.0.0_r51android-13.0.0_r50android-13.0.0_r49android-13.0.0_r48android-13.0.0_r47android-13.0.0_r46android-13.0.0_r45android-13.0.0_r44android-13.0.0_r43android-13.0.0_r42android-13.0.0_r41android-13.0.0_r40android-13.0.0_r39android-13.0.0_r38android-13.0.0_r37android-13.0.0_r36android-13.0.0_r35android-13.0.0_r34android-13.0.0_r33android-13.0.0_r32android13-qpr3-s9-releaseandroid13-qpr3-s8-releaseandroid13-qpr3-s7-releaseandroid13-qpr3-s6-releaseandroid13-qpr3-s5-releaseandroid13-qpr3-s4-releaseandroid13-qpr3-s3-releaseandroid13-qpr3-s2-releaseandroid13-qpr3-s14-releaseandroid13-qpr3-s13-releaseandroid13-qpr3-s12-releaseandroid13-qpr3-s11-releaseandroid13-qpr3-s10-releaseandroid13-qpr3-s1-releaseandroid13-qpr3-releaseandroid13-qpr3-c-s8-releaseandroid13-qpr3-c-s7-releaseandroid13-qpr3-c-s6-releaseandroid13-qpr3-c-s5-releaseandroid13-qpr3-c-s4-releaseandroid13-qpr3-c-s3-releaseandroid13-qpr3-c-s2-releaseandroid13-qpr3-c-s12-releaseandroid13-qpr3-c-s11-releaseandroid13-qpr3-c-s10-releaseandroid13-qpr3-c-s1-releaseandroid13-qpr2-s9-releaseandroid13-qpr2-s8-releaseandroid13-qpr2-s7-releaseandroid13-qpr2-s6-releaseandroid13-qpr2-s5-releaseandroid13-qpr2-s3-releaseandroid13-qpr2-s2-releaseandroid13-qpr2-s12-releaseandroid13-qpr2-s11-releaseandroid13-qpr2-s10-releaseandroid13-qpr2-s1-releaseandroid13-qpr2-releaseandroid13-qpr2-b-s1-releaseandroid13-d4-s2-releaseandroid13-d4-s1-releaseandroid13-d4-release
Original change: https://android-review.googlesource.com/c/platform/external/webrtc/+/2062410 Change-Id: I1aa9f459b825711b800cc65782979943a9151ec7 Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
Diffstat (limited to 'third_party/abseil-cpp/absl/synchronization/internal/futex.h')
-rw-r--r--third_party/abseil-cpp/absl/synchronization/internal/futex.h154
1 files changed, 154 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/synchronization/internal/futex.h b/third_party/abseil-cpp/absl/synchronization/internal/futex.h
new file mode 100644
index 0000000000..06fbd6d072
--- /dev/null
+++ b/third_party/abseil-cpp/absl/synchronization/internal/futex.h
@@ -0,0 +1,154 @@
+// Copyright 2020 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#ifndef ABSL_SYNCHRONIZATION_INTERNAL_FUTEX_H_
+#define ABSL_SYNCHRONIZATION_INTERNAL_FUTEX_H_
+
+#include "absl/base/config.h"
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <sys/time.h>
+#include <unistd.h>
+#endif
+
+#ifdef __linux__
+#include <linux/futex.h>
+#include <sys/syscall.h>
+#endif
+
+#include <errno.h>
+#include <stdio.h>
+#include <time.h>
+
+#include <atomic>
+#include <cstdint>
+
+#include "absl/base/optimization.h"
+#include "absl/synchronization/internal/kernel_timeout.h"
+
+#ifdef ABSL_INTERNAL_HAVE_FUTEX
+#error ABSL_INTERNAL_HAVE_FUTEX may not be set on the command line
+#elif defined(__BIONIC__)
+// Bionic supports all the futex operations we need even when some of the futex
+// definitions are missing.
+#define ABSL_INTERNAL_HAVE_FUTEX
+#elif defined(__linux__) && defined(FUTEX_CLOCK_REALTIME)
+// FUTEX_CLOCK_REALTIME requires Linux >= 2.6.28.
+#define ABSL_INTERNAL_HAVE_FUTEX
+#endif
+
+#ifdef ABSL_INTERNAL_HAVE_FUTEX
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace synchronization_internal {
+
+// Some Android headers are missing these definitions even though they
+// support these futex operations.
+#ifdef __BIONIC__
+#ifndef SYS_futex
+#define SYS_futex __NR_futex
+#endif
+#ifndef FUTEX_WAIT_BITSET
+#define FUTEX_WAIT_BITSET 9
+#endif
+#ifndef FUTEX_PRIVATE_FLAG
+#define FUTEX_PRIVATE_FLAG 128
+#endif
+#ifndef FUTEX_CLOCK_REALTIME
+#define FUTEX_CLOCK_REALTIME 256
+#endif
+#ifndef FUTEX_BITSET_MATCH_ANY
+#define FUTEX_BITSET_MATCH_ANY 0xFFFFFFFF
+#endif
+#endif
+
+#if defined(__NR_futex_time64) && !defined(SYS_futex_time64)
+#define SYS_futex_time64 __NR_futex_time64
+#endif
+
+#if defined(SYS_futex_time64) && !defined(SYS_futex)
+#define SYS_futex SYS_futex_time64
+#endif
+
+class FutexImpl {
+ public:
+ static int WaitUntil(std::atomic<int32_t> *v, int32_t val,
+ KernelTimeout t) {
+ int err = 0;
+ if (t.has_timeout()) {
+ // https://locklessinc.com/articles/futex_cheat_sheet/
+ // Unlike FUTEX_WAIT, FUTEX_WAIT_BITSET uses absolute time.
+ struct timespec abs_timeout = t.MakeAbsTimespec();
+ // Atomically check that the futex value is still 0, and if it
+ // is, sleep until abs_timeout or until woken by FUTEX_WAKE.
+ err = syscall(
+ SYS_futex, reinterpret_cast<int32_t *>(v),
+ FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME, val,
+ &abs_timeout, nullptr, FUTEX_BITSET_MATCH_ANY);
+ } else {
+ // Atomically check that the futex value is still 0, and if it
+ // is, sleep until woken by FUTEX_WAKE.
+ err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v),
+ FUTEX_WAIT | FUTEX_PRIVATE_FLAG, val, nullptr);
+ }
+ if (ABSL_PREDICT_FALSE(err != 0)) {
+ err = -errno;
+ }
+ return err;
+ }
+
+ static int WaitBitsetAbsoluteTimeout(std::atomic<int32_t> *v, int32_t val,
+ int32_t bits,
+ const struct timespec *abstime) {
+ int err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v),
+ FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG, val, abstime,
+ nullptr, bits);
+ if (ABSL_PREDICT_FALSE(err != 0)) {
+ err = -errno;
+ }
+ return err;
+ }
+
+ static int Wake(std::atomic<int32_t> *v, int32_t count) {
+ int err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v),
+ FUTEX_WAKE | FUTEX_PRIVATE_FLAG, count);
+ if (ABSL_PREDICT_FALSE(err < 0)) {
+ err = -errno;
+ }
+ return err;
+ }
+
+ // FUTEX_WAKE_BITSET
+ static int WakeBitset(std::atomic<int32_t> *v, int32_t count, int32_t bits) {
+ int err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v),
+ FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG, count, nullptr,
+ nullptr, bits);
+ if (ABSL_PREDICT_FALSE(err < 0)) {
+ err = -errno;
+ }
+ return err;
+ }
+};
+
+class Futex : public FutexImpl {};
+
+} // namespace synchronization_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_INTERNAL_HAVE_FUTEX
+
+#endif // ABSL_SYNCHRONIZATION_INTERNAL_FUTEX_H_