import(life): ...

6 files changed, 73 insertions, 3 deletions

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 806ec74..139d2ba 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -21,3 +21,6 @@ target_link_libraries(main PRIVATE cru_system)
 

 add_executable(data_race_demo DataRaceDemo.cpp)

 target_link_libraries(data_race_demo PRIVATE cru_system)

+

+add_executable(mutex_avoid_data_race_demo MutexAvoidDataRaceDemo.cpp)

+target_link_libraries(mutex_avoid_data_race_demo PRIVATE cru_system)

diff --git a/works/life/operating-system-experiment/DataRaceDemo.cpp b/works/life/operating-system-experiment/DataRaceDemo.cpp
index 9589eb3..a2f98d9 100644
--- a/works/life/operating-system-experiment/DataRaceDemo.cpp
+++ b/works/life/operating-system-experiment/DataRaceDemo.cpp
@@ -21,7 +21,7 @@ int main() {
   t1.Join();
   t2.Join();
   std::cout << "Answer is " << data << ", which is "
-            << (data == 200000 ? "correct" : "false") << '\n';
+            << (data == 2000000 ? "correct" : "false") << '\n';
 
   return 0;
 }
diff --git a/works/life/operating-system-experiment/Mutex.cpp b/works/life/operating-system-experiment/Mutex.cpp
index 6a91885..b7d0cb6 100644
--- a/works/life/operating-system-experiment/Mutex.cpp
+++ b/works/life/operating-system-experiment/Mutex.cpp
@@ -1,7 +1,6 @@
 #include "Mutex.h"
 
 #include <cassert>
-#include <pthread.h>
 
 #ifndef CRU_WINDOWS
 #include <errno.h>
@@ -10,6 +9,8 @@
 namespace cru {
 Mutex::Mutex() {
 #ifdef CRU_WINDOWS
+  handle_ = CreateMutexW(nullptr, FALSE, nullptr);
+  assert(handle_);
 #else
   mutex_ = std::make_unique<pthread_mutex_t>();
 
@@ -20,16 +21,25 @@ Mutex::Mutex() {
 
 Mutex::Mutex(Mutex &&other)
 #ifdef CRU_WINDOWS
+    : handle_(other.handle_)
 #else
     : mutex_(std::move(other.mutex_))
 #endif
 {
+#ifdef CRU_WINDOWS
+  other.handle_ = nullptr;
+#endif
 }
 
 Mutex &Mutex::operator=(Mutex &&other) {
   if (this != &other) {
     Destroy();
+#ifdef CRU_WINDOWS
+    handle_ = other.handle_;
+    other.handle_ = nullptr;
+#else
     mutex_ = std::move(other.mutex_);
+#endif
   }
   return *this;
 }
@@ -38,6 +48,8 @@ Mutex::~Mutex() { Destroy(); }
 
 void Mutex::Lock() {
 #ifdef CRU_WINDOWS
+  auto c = WaitForSingleObject(handle_, INFINITE);
+  assert(c == WAIT_OBJECT_0);
 #else
   assert(mutex_);
   auto c = pthread_mutex_lock(mutex_.get());
@@ -47,6 +59,9 @@ void Mutex::Lock() {
 
 bool Mutex::TryLock() {
 #ifdef CRU_WINDOWS
+  auto c = WaitForSingleObject(handle_, 0);
+  assert(c == WAIT_OBJECT_0 || c == WAIT_TIMEOUT);
+  return c == WAIT_OBJECT_0 ? true : false;
 #else
   assert(mutex_);
   auto c = pthread_mutex_trylock(mutex_.get());
@@ -57,6 +72,8 @@ bool Mutex::TryLock() {
 
 void Mutex::Unlock() {
 #ifdef CRU_WINDOWS
+  auto c = ReleaseMutex(handle_);
+  assert(c);
 #else
   assert(mutex_);
   auto c = pthread_mutex_unlock(mutex_.get());
@@ -66,6 +83,10 @@ void Mutex::Unlock() {
 
 void Mutex::Destroy() {
 #ifdef CRU_WINDOWS
+  if (handle_ != nullptr) {
+    auto c = CloseHandle(handle_);
+    assert(c);
+  }
 #else
   if (mutex_ != nullptr) {
     auto c = pthread_mutex_destroy(mutex_.get());
diff --git a/works/life/operating-system-experiment/Mutex.h b/works/life/operating-system-experiment/Mutex.h
index 163d9ca..d561f1a 100644
--- a/works/life/operating-system-experiment/Mutex.h
+++ b/works/life/operating-system-experiment/Mutex.h
@@ -35,6 +35,7 @@ private:
 
 private:
 #ifdef CRU_WINDOWS
+  HANDLE handle_;
 #else
   std::unique_ptr<pthread_mutex_t> mutex_;
 #endif
diff --git a/works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp b/works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp
new file mode 100644
index 0000000..81a7aa1
--- /dev/null
+++ b/works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp
@@ -0,0 +1,42 @@
+#include "Mutex.h"

+#include "Thread.h"

+

+#include <iostream>

+

+int main() {

+

+  unsigned data = 0;

+  cru::Mutex mutex;

+  mutex.Lock();

+

+  cru::Thread t1([&data, &mutex] {

+    for (int i = 0; i < 100000; i++) {

+      mutex.Lock();

+      data += 10;

+      //std::cout << "Data is now: " << data << '\n';

+      mutex.Unlock();

+    }

+  });

+

+  cru::Thread t2([&data, &mutex] {

+    for (int i = 0; i < 100000; i++) {

+      mutex.Lock();

+      data += 10;

+      //std::cout << "Data is now: " << data << '\n';

+      mutex.Unlock();

+    }

+  });

+

+  std::cout << "Created thread: " << t1.GetNativeID() << '\n';

+  std::cout << "Created thread: " << t2.GetNativeID() << '\n';

+

+  mutex.Unlock();

+

+  t1.Join();

+  t2.Join();

+

+  std::cout << "Answer is " << data << ", which is "

+            << (data == 2000000 ? "correct" : "false") << '\n';

+

+  return 0;

+}

diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index 7e3c784..a5f526d 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -112,7 +112,10 @@ void Thread::Destroy() noexcept {
     joined_ = false;

 #ifdef CRU_WINDOWS

     thread_id_ = 0;

-    thread_handle_ = nullptr;

+    if (thread_handle_ != nullptr) {

+      CloseHandle(thread_handle_);

+      thread_handle_ = nullptr;

+    }

 #else

     thread_ = nullptr;

 #endif