diff --git a/src/README.md b/src/README.md
index b97b10f..95036b0 100644
--- a/src/README.md
+++ b/src/README.md
@@ -31,3 +31,7 @@ A high-performance spin mutex and locker.
 ## Protocol/TelentProtocol.h/cpp
 
 An implementation of Telnet protocol.
+
+## Utility/ThreadLocal.h/cpp
+
+A high-performance thread local storage.
diff --git a/src/Utility/ThreadLocal.cpp b/src/Utility/ThreadLocal.cpp
new file mode 100644
index 0000000..e4529ef
--- /dev/null
+++ b/src/Utility/ThreadLocal.cpp
@@ -0,0 +1,31 @@
+ /*
+ * Copyright 2020, WindTerm.
+ *
+ * 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.
+ */
+
+#include "ThreadLocal.h"
+
+#include <QThread>
+
+void ThreadLocalWatcher::stopWatchCurrentThread() {
+	QThread::currentThread()->disconnect(this);
+}
+
+void ThreadLocalWatcher::watchCurrentThread() {
+	boost::thread::id id = boost::this_thread::get_id();
+
+	connect(QThread::currentThread(), &QThread::finished, this, [this, id]() {
+		clear(id);
+	});
+}
\ No newline at end of file
diff --git a/src/Utility/ThreadLocal.h b/src/Utility/ThreadLocal.h
new file mode 100644
index 0000000..7ffbd3a
--- /dev/null
+++ b/src/Utility/ThreadLocal.h
@@ -0,0 +1,205 @@
+ /*
+ * Copyright 2020, WindTerm.
+ *
+ * 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.
+ */
+
+#ifndef THREADLOCAL_H
+#define THREADLOCAL_H
+
+#include <QObject>
+
+#include <mutex>
+#include <vector>
+#include <boost/thread.hpp>
+
+#include "Spin.h"
+
+#define STATIC_LOCAL_COUNT	6
+
+class ThreadLocalWatcher : public QObject {
+	Q_OBJECT
+
+public:
+	ThreadLocalWatcher() = default;
+
+protected:
+	void stopWatchCurrentThread();
+	void watchCurrentThread();
+	virtual void clear(const boost::thread::id &id) = 0;
+
+private:
+	Q_DISABLE_COPY(ThreadLocalWatcher)
+};
+
+template <typename T>
+class ThreadLocal : public ThreadLocalWatcher {
+public:
+	ThreadLocal()
+		: m_mainThreadId(boost::this_thread::get_id())
+	{
+		for (int i = 0; i < STATIC_LOCAL_COUNT; i++) {
+			m_staticLocals[i] = nullptr;
+		}
+	}
+	
+	~ThreadLocal() {
+		clearAll();
+	}
+
+	void clear(const boost::thread::id &id) {
+		std::lock_guard<SpinMutex> lock(m_mutex);
+
+		if (removeLocal(id)) {
+			stopWatchCurrentThread();
+		}
+	}
+
+	void clearAll() {
+		std::lock_guard<SpinMutex> lock(m_mutex);
+
+		for (int i = 0; i < STATIC_LOCAL_COUNT; i++) {
+			if (Local *local = m_staticLocals[i]) {
+				delete local;
+				m_staticLocals[i] = nullptr;
+			}
+		}
+
+		if (m_dynamicLocals) {
+			for (Local *local : *m_dynamicLocals) {
+				delete local;
+			}
+			m_dynamicLocals.reset(nullptr);
+		}
+	}
+
+	T *get() {
+		boost::thread::id id = boost::this_thread::get_id();
+
+		for (const Local *local : m_staticLocals) {
+			if (local && local->id == id) {
+				return local->ptr;
+			}
+		}
+
+		if (m_dynamicLocals) {
+			std::lock_guard<SpinMutex> lock(m_mutex);
+
+			for (const Local *local : *m_dynamicLocals) {
+				if (local && local->id == id) {
+					return local->ptr;
+				}
+			}
+		}
+		return nullptr;
+	}
+
+	boost::thread::id mainThreadId() const {
+		return m_mainThreadId;
+	}
+
+	void reset(T *t) {
+		std::lock_guard<SpinMutex> lock(m_mutex);
+		boost::thread::id id = boost::this_thread::get_id();
+
+		bool removed = removeLocal(id);
+		bool added = addLocal(id, t);
+
+		if (id != m_mainThreadId) {
+			if (removed) {
+				if (added == false) {
+					stopWatchCurrentThread();
+				}
+			} else {
+				if (added) {
+					watchCurrentThread();
+				}
+			}
+		}
+	}
+
+private:
+	bool addLocal(const boost::thread::id &id, T *t) {
+		if (t == nullptr) {
+			return false;
+		}
+
+		for (int i = 0; i < STATIC_LOCAL_COUNT; i++) {
+			if (m_staticLocals[i] == nullptr) {
+				m_staticLocals[i] = new Local(id, t);
+
+				return true;
+			}
+		}
+
+		if (m_dynamicLocals.get() == nullptr) {
+			m_dynamicLocals = std::make_unique<LocalVector>();
+		}
+		m_dynamicLocals->push_back(new Local(id, t));
+		return true;
+	}
+
+	bool removeLocal(const boost::thread::id &id) {
+		for (int i = 0; i < STATIC_LOCAL_COUNT; i++) {
+			Local *local = m_staticLocals[i];
+
+			if (local && local->id == id) {
+				delete local;
+				m_staticLocals[i] = nullptr;
+
+				return true;
+			}
+		}
+
+		if (m_dynamicLocals) {
+			for (auto it = m_dynamicLocals->begin(); it != m_dynamicLocals->end(); ++it) {
+				Local *local = *it;
+
+				if (local && local->id == id) {
+					delete local;
+					m_dynamicLocals->erase(it);
+
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
+private:
+	Q_DISABLE_COPY(ThreadLocal)
+
+	struct Local {
+		boost::thread::id id;
+		T *ptr;
+
+		Local(boost::thread::id id_, T *ptr_)
+			: id(id_)
+			, ptr(ptr_)
+		{}
+
+		~Local() {
+			delete ptr;
+			ptr = nullptr;
+		}
+	};
+	typedef std::vector<Local *> LocalVector;
+	std::unique_ptr<LocalVector> m_dynamicLocals;
+
+	Local *m_staticLocals[STATIC_LOCAL_COUNT];
+
+	boost::thread::id m_mainThreadId;
+	SpinMutex m_mutex;
+};
+
+#endif // THREADLOCAL_H
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