Initial Commit

1 files changed, 311 insertions, 0 deletions

diff --git a/absl/synchronization/internal/mutex_nonprod.cc b/absl/synchronization/internal/mutex_nonprod.cc
new file mode 100644
index 00000000..94be54b8
--- /dev/null
+++ b/absl/synchronization/internal/mutex_nonprod.cc
@@ -0,0 +1,311 @@
+// Copyright 2017 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
+//
+//      http://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.
+
+// Implementation of a small subset of Mutex and CondVar functionality
+// for platforms where the production implementation hasn't been fully
+// ported yet.
+
+#include "absl/synchronization/mutex.h"
+
+#if defined(_WIN32)
+#include <chrono>  // NOLINT(build/c++11)
+#else
+#include <sys/time.h>
+#include <time.h>
+#endif
+
+#include <algorithm>
+
+#include "absl/base/internal/raw_logging.h"
+#include "absl/time/time.h"
+
+namespace absl {
+namespace synchronization_internal {
+
+namespace {
+
+// Return the current time plus the timeout.
+absl::Time DeadlineFromTimeout(absl::Duration timeout) {
+  return absl::Now() + timeout;
+}
+
+// Limit the deadline to a positive, 32-bit time_t value to accommodate
+// implementation restrictions.  This also deals with InfinitePast and
+// InfiniteFuture.
+absl::Time LimitedDeadline(absl::Time deadline) {
+  deadline = std::max(absl::FromTimeT(0), deadline);
+  deadline = std::min(deadline, absl::FromTimeT(0x7fffffff));
+  return deadline;
+}
+
+}  // namespace
+
+#if defined(_WIN32)
+
+MutexImpl::MutexImpl() {}
+
+MutexImpl::~MutexImpl() {
+  if (locked_) {
+    std_mutex_.unlock();
+  }
+}
+
+void MutexImpl::Lock() {
+  std_mutex_.lock();
+  locked_ = true;
+}
+
+bool MutexImpl::TryLock() {
+  bool locked = std_mutex_.try_lock();
+  if (locked) locked_ = true;
+  return locked;
+}
+
+void MutexImpl::Unlock() {
+  locked_ = false;
+  released_.SignalAll();
+  std_mutex_.unlock();
+}
+
+CondVarImpl::CondVarImpl() {}
+
+CondVarImpl::~CondVarImpl() {}
+
+void CondVarImpl::Signal() { std_cv_.notify_one(); }
+
+void CondVarImpl::SignalAll() { std_cv_.notify_all(); }
+
+void CondVarImpl::Wait(MutexImpl* mu) {
+  mu->released_.SignalAll();
+  std_cv_.wait(mu->std_mutex_);
+}
+
+bool CondVarImpl::WaitWithDeadline(MutexImpl* mu, absl::Time deadline) {
+  mu->released_.SignalAll();
+  time_t when = ToTimeT(deadline);
+  int64_t nanos = ToInt64Nanoseconds(deadline - absl::FromTimeT(when));
+  std::chrono::system_clock::time_point deadline_tp =
+      std::chrono::system_clock::from_time_t(when) +
+      std::chrono::duration_cast<std::chrono::system_clock::duration>(
+          std::chrono::nanoseconds(nanos));
+  auto deadline_since_epoch =
+      std::chrono::duration_cast<std::chrono::duration<double>>(
+          deadline_tp - std::chrono::system_clock::from_time_t(0));
+  return std_cv_.wait_until(mu->std_mutex_, deadline_tp) ==
+         std::cv_status::timeout;
+}
+
+#else  // ! _WIN32
+
+MutexImpl::MutexImpl() {
+  ABSL_RAW_CHECK(pthread_mutex_init(&pthread_mutex_, nullptr) == 0,
+                 "pthread error");
+}
+
+MutexImpl::~MutexImpl() {
+  if (locked_) {
+    ABSL_RAW_CHECK(pthread_mutex_unlock(&pthread_mutex_) == 0, "pthread error");
+  }
+  ABSL_RAW_CHECK(pthread_mutex_destroy(&pthread_mutex_) == 0, "pthread error");
+}
+
+void MutexImpl::Lock() {
+  ABSL_RAW_CHECK(pthread_mutex_lock(&pthread_mutex_) == 0, "pthread error");
+  locked_ = true;
+}
+
+bool MutexImpl::TryLock() {
+  bool locked = (0 == pthread_mutex_trylock(&pthread_mutex_));
+  if (locked) locked_ = true;
+  return locked;
+}
+
+void MutexImpl::Unlock() {
+  locked_ = false;
+  released_.SignalAll();
+  ABSL_RAW_CHECK(pthread_mutex_unlock(&pthread_mutex_) == 0, "pthread error");
+}
+
+CondVarImpl::CondVarImpl() {
+  ABSL_RAW_CHECK(pthread_cond_init(&pthread_cv_, nullptr) == 0,
+                 "pthread error");
+}
+
+CondVarImpl::~CondVarImpl() {
+  ABSL_RAW_CHECK(pthread_cond_destroy(&pthread_cv_) == 0, "pthread error");
+}
+
+void CondVarImpl::Signal() {
+  ABSL_RAW_CHECK(pthread_cond_signal(&pthread_cv_) == 0, "pthread error");
+}
+
+void CondVarImpl::SignalAll() {
+  ABSL_RAW_CHECK(pthread_cond_broadcast(&pthread_cv_) == 0, "pthread error");
+}
+
+void CondVarImpl::Wait(MutexImpl* mu) {
+  mu->released_.SignalAll();
+  ABSL_RAW_CHECK(pthread_cond_wait(&pthread_cv_, &mu->pthread_mutex_) == 0,
+                 "pthread error");
+}
+
+bool CondVarImpl::WaitWithDeadline(MutexImpl* mu, absl::Time deadline) {
+  mu->released_.SignalAll();
+  struct timespec ts = ToTimespec(deadline);
+  int rc = pthread_cond_timedwait(&pthread_cv_, &mu->pthread_mutex_, &ts);
+  if (rc == ETIMEDOUT) return true;
+  ABSL_RAW_CHECK(rc == 0, "pthread error");
+  return false;
+}
+
+#endif  // ! _WIN32
+
+void MutexImpl::Await(const Condition& cond) {
+  if (cond.Eval()) return;
+  released_.SignalAll();
+  do {
+    released_.Wait(this);
+  } while (!cond.Eval());
+}
+
+bool MutexImpl::AwaitWithDeadline(const Condition& cond, absl::Time deadline) {
+  if (cond.Eval()) return true;
+  released_.SignalAll();
+  while (true) {
+    if (released_.WaitWithDeadline(this, deadline)) return false;
+    if (cond.Eval()) return true;
+  }
+}
+
+}  // namespace synchronization_internal
+
+Mutex::Mutex() {}
+
+Mutex::~Mutex() {}
+
+void Mutex::Lock() { impl()->Lock(); }
+
+void Mutex::Unlock() { impl()->Unlock(); }
+
+bool Mutex::TryLock() { return impl()->TryLock(); }
+
+void Mutex::ReaderLock() { Lock(); }
+
+void Mutex::ReaderUnlock() { Unlock(); }
+
+void Mutex::Await(const Condition& cond) { impl()->Await(cond); }
+
+void Mutex::LockWhen(const Condition& cond) {
+  Lock();
+  Await(cond);
+}
+
+bool Mutex::AwaitWithDeadline(const Condition& cond, absl::Time deadline) {
+  return impl()->AwaitWithDeadline(
+      cond, synchronization_internal::LimitedDeadline(deadline));
+}
+
+bool Mutex::AwaitWithTimeout(const Condition& cond, absl::Duration timeout) {
+  return AwaitWithDeadline(
+      cond, synchronization_internal::DeadlineFromTimeout(timeout));
+}
+
+bool Mutex::LockWhenWithDeadline(const Condition& cond, absl::Time deadline) {
+  Lock();
+  return AwaitWithDeadline(cond, deadline);
+}
+
+bool Mutex::LockWhenWithTimeout(const Condition& cond, absl::Duration timeout) {
+  return LockWhenWithDeadline(
+      cond, synchronization_internal::DeadlineFromTimeout(timeout));
+}
+
+bool Mutex::ReaderLockWhenWithTimeout(const Condition& cond,
+                                      absl::Duration timeout) {
+  return LockWhenWithTimeout(cond, timeout);
+}
+bool Mutex::ReaderLockWhenWithDeadline(const Condition& cond,
+                                       absl::Time deadline) {
+  return LockWhenWithDeadline(cond, deadline);
+}
+
+void Mutex::EnableDebugLog(const char*) {}
+void Mutex::EnableInvariantDebugging(void (*)(void*), void*) {}
+void Mutex::ForgetDeadlockInfo() {}
+void Mutex::AssertHeld() const {}
+void Mutex::AssertReaderHeld() const {}
+void Mutex::AssertNotHeld() const {}
+
+CondVar::CondVar() {}
+
+CondVar::~CondVar() {}
+
+void CondVar::Signal() { impl()->Signal(); }
+
+void CondVar::SignalAll() { impl()->SignalAll(); }
+
+void CondVar::Wait(Mutex* mu) { return impl()->Wait(mu->impl()); }
+
+bool CondVar::WaitWithDeadline(Mutex* mu, absl::Time deadline) {
+  return impl()->WaitWithDeadline(
+      mu->impl(), synchronization_internal::LimitedDeadline(deadline));
+}
+
+bool CondVar::WaitWithTimeout(Mutex* mu, absl::Duration timeout) {
+  return WaitWithDeadline(mu, absl::Now() + timeout);
+}
+
+void CondVar::EnableDebugLog(const char*) {}
+
+#ifdef THREAD_SANITIZER
+extern "C" void __tsan_read1(void *addr);
+#else
+#define __tsan_read1(addr)  // do nothing if TSan not enabled
+#endif
+
+// A function that just returns its argument, dereferenced
+static bool Dereference(void *arg) {
+  // ThreadSanitizer does not instrument this file for memory accesses.
+  // This function dereferences a user variable that can participate
+  // in a data race, so we need to manually tell TSan about this memory access.
+  __tsan_read1(arg);
+  return *(static_cast<bool *>(arg));
+}
+
+Condition::Condition() {}   // null constructor, used for kTrue only
+const Condition Condition::kTrue;
+
+Condition::Condition(bool (*func)(void *), void *arg)
+    : eval_(&CallVoidPtrFunction),
+      function_(func),
+      method_(nullptr),
+      arg_(arg) {}
+
+bool Condition::CallVoidPtrFunction(const Condition *c) {
+  return (*c->function_)(c->arg_);
+}
+
+Condition::Condition(const bool *cond)
+    : eval_(CallVoidPtrFunction),
+      function_(Dereference),
+      method_(nullptr),
+      // const_cast is safe since Dereference does not modify arg
+      arg_(const_cast<bool *>(cond)) {}
+
+bool Condition::Eval() const {
+  // eval_ == null for kTrue
+  return (this->eval_ == nullptr) || (*this->eval_)(this);
+}
+
+}  // namespace absl