open source

Conch/source/common/misc/boostSemaphore.h

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+
+#include <condition_variable>
+#include <thread> 
+
+namespace laya {
+    class semaphore {
+        unsigned int count_;
+        std::mutex mutex_;
+        std::condition_variable condition_;
+    public:
+        //构造一个semaphore 初始值为initial.
+        explicit semaphore(unsigned int initial) : count_(initial) {}
+
+        //增加计数，并且通知其他的wait醒来检查。
+        void signal() {
+            {
+                std::unique_lock<std::mutex> lock(mutex_);
+                ++count_;
+            }
+            condition_.notify_one();
+        }
+
+        //等待，直到有人 signal，signal到count>0,wait成功会减count
+        void wait() {
+            std::unique_lock<std::mutex> lock(mutex_);
+            while (count_ == 0) {
+                condition_.wait(lock);
+            }
+            --count_;
+        }
+
+        //等待，如果没有人增加计数的的话在时间到后会醒来返回。成功会减count
+        //这个不会要求有count
+        void wait(int ms) {
+            std::unique_lock<std::mutex> lock(mutex_);
+            condition_.wait_until(lock, std::chrono::system_clock::now() + std::chrono::milliseconds(ms));
+            --count_;
+        }
+    };
+}