feat add CountDownLatch

CMakeLists.txt

@@ -19,6 +19,8 @@ target_sources(${PROJECT_NAME} PRIVATE
             src/ulib/concorrency/mutex.h
             src/ulib/concorrency/condition_variable.cpp
             src/ulib/concorrency/condition_variable.h
+            src/ulib/concorrency/countdown_latch.cpp
+            src/ulib/concorrency/countdown_latch.h
             src/ulib/concorrency/internal/mutex_impl.cpp
             src/ulib/concorrency/internal/mutex_impl.h
             src/ulib/concorrency/internal/condition_variable_impl.cpp

src/ulib/concorrency/countdown_latch.cpp

@@ -0,0 +1,28 @@
+#include "countdown_latch.h"
+#include <assert.h>
+
+namespace ulib {
+
+CountDownLatch::CountDownLatch(uint32_t count) : count_(count) {
+    assert(count > 0);
+}
+
+void
+CountDownLatch::CountDown()
+{
+    MutexGuard guard(count_lock_);
+    assert(count_ > 0);
+    --count_;
+    if (count_ == 0) { count_cond_.NotifyAll(); }
+}
+
+void
+CountDownLatch::Await()
+{
+    if (count_ == 0) { return; }
+    MutexGuard guard(count_lock_);
+    while (count_ > 0) { count_cond_.Wait(guard); }
+    assert(count_ == 0);
+}
+
+}// namespace ulib

src/ulib/concorrency/countdown_latch.h

@@ -0,0 +1,17 @@
+#include "ulib/base/types.h"
+#include "ulib/concorrency/mutex.h"
+#include "ulib/concorrency/event.h"
+
+namespace ulib {
+class CountDownLatch {
+public:
+    CountDownLatch(uint32_t count);
+    void CountDown();
+    void Await();
+
+private:
+    ulib::int64_t count_;
+    Mutex count_lock_;
+    ConditionVariable count_cond_;
+};
+}// namespace ulib

tests/CMakeLists.txt

@@ -2,10 +2,11 @@ set(CMAKE_CXX_STANDARD 98)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 add_executable(ulib_test
-        ulib/base/types_test.cpp
-        ulib/log/log_test.cpp
-        ulib/concorrency/mutex_test.cpp
-        ulib/concorrency/event_test.cpp
+        ulib/base/types_unittest.cpp
+        ulib/log/log_unittest.cpp
+        ulib/concorrency/mutex_unittest.cpp
+        ulib/concorrency/event_unittest.cpp
+        ulib/concorrency/countdown_latch_unittest.cpp
 )
 target_link_libraries(ulib_test PRIVATE
         ulib

tests/ulib/concorrency/countdown_latch_unittest.cpp

@@ -0,0 +1,53 @@
+#include <gtest/gtest.h>
+#include <ulib/concorrency/countdown_latch.h>
+#include <pthread.h>
+
+TEST(CountdownLatch, CountDownLatch)
+{
+    ulib::CountDownLatch latch(1);
+    latch.CountDown();
+    latch.Await();
+}
+
+TEST(CountdownLatch, CountDownLatch2)
+{
+    ulib::CountDownLatch latch(2);
+    latch.CountDown();
+    latch.CountDown();
+    latch.Await();
+}
+
+void *
+CountDownThread(void *arg)
+{
+    ulib::CountDownLatch *latch = (ulib::CountDownLatch *) arg;
+    latch->CountDown();
+    return NULL;
+}
+
+TEST(CountdownLatch, DoubleCountDownLatch)
+{
+    ulib::CountDownLatch latch(2);
+    pthread_t thread;
+    pthread_create(&thread, NULL, CountDownThread, &latch);
+    latch.CountDown();
+    latch.Await();
+    pthread_join(thread, NULL);
+}
+
+TEST(CountdownLatch, MultiThreadCountDownLatch)
+{
+#define THREAD_NUM 10
+    ulib::CountDownLatch latch(THREAD_NUM);
+    pthread_t thread[THREAD_NUM];
+    for (int i = 0; i < THREAD_NUM; ++i) { pthread_create(&thread[i], NULL, CountDownThread, &latch); }
+    latch.Await();
+    for (int i = 0; i < THREAD_NUM; ++i) { pthread_join(thread[i], NULL); }
+}
+
+TEST(CoundownLatch, Assert)
+{
+    ulib::CountDownLatch latch(1);
+    latch.CountDown();
+    EXPECT_DEATH(latch.CountDown(), "Assertion.*");
+}