upd: write class ReadWriteLock

backend/src/bs-utility.cpp

@@ -10,4 +10,34 @@ BlockingStringStream &BlockingStringStream::getline(std::string &str,
   std::getline(internalStream, str, delim);
 
   return *this;
+}
+
+ReadWriteLock::ReadWriteLock() : readers(0), is_writing(false) {}
+
+void ReadWriteLock::startRead() {
+  std::unique_lock<std::mutex> lock(mtx);
+  cv.wait(lock, [this] { return !is_writing; });  // 等待写操作结束
+  readers++;
+}
+
+void ReadWriteLock::endRead() {
+  std::unique_lock<std::mutex> lock(mtx);
+  readers--;
+  if (readers == 0) {
+    cv.notify_one();  // 唤醒一个等待的写操作
+  }
+}
+
+void ReadWriteLock::startWrite() {
+  std::unique_lock<std::mutex> lock(mtx);
+  cv.wait(lock, [this] {
+    return readers == 0 && !is_writing;
+  });  // 等待读操作和写操作结束
+  is_writing = true;
+}
+
+void ReadWriteLock::endWrite() {
+  std::unique_lock<std::mutex> lock(mtx);
+  is_writing = false;
+  cv.notify_all();  // 唤醒所有等待的读操作和写操作
 }