add promise code.

.vscode/c_cpp_properties.json

@@ -4,7 +4,7 @@
             "name": "Linux",
             "includePath": [
                 "${workspaceFolder}/**",
-                "/opt/Libraries/boost_1_85_0/include"
+                "/opt/Libraries/boost_1_86_0/include"
             ],
             "defines": [],
             "compilerPath": "/usr/bin/gcc",

UnitTest/CMakeLists.txt

@@ -32,6 +32,7 @@ add_executable(UnitTest main.cpp
     Universal/BoostLogTest.cpp
     Universal/DateTimeTest.cpp
     Universal/MessageManagerTest.cpp
+    Universal/PromiseTest.cpp
     Universal/SingletonTest.cpp
 )
 

UnitTest/Universal/PromiseTest.cpp

@@ -0,0 +1,300 @@
+#include "Promise.h"
+#include <boost/test/unit_test.hpp>
+#include <sstream>
+#include <variant>
+#include <vector>
+
+template <typename T>
+static inline T waitForValue(const Promise<T> &promise, const T &initial) {
+    T value(initial);
+    promise.then([&](const T &res) { value = res; }).wait();
+    return value;
+}
+
+template <typename T>
+static inline T waitForValue(const Promise<void> &promise, const T &initial, const T &expected) {
+    T value(initial);
+    promise.then([&]() { value = expected; }).wait();
+    return value;
+}
+
+BOOST_AUTO_TEST_CASE(Then) {
+    std::vector<std::variant<int, std::string>> values;
+    auto input = Promise<int>::resolve(42);
+    auto output = input.then([&](int res) {
+        values.push_back(res);
+        return std::to_string(res + 1);
+    });
+    output.then([&](const std::string &res) { values.push_back(res); }).then([&]() { values.push_back(44); }).wait();
+
+    BOOST_CHECK_EQUAL(values.size(), 3);
+    BOOST_CHECK_EQUAL(std::get<int>(values[0]), 42);
+    BOOST_CHECK_EQUAL(std::get<std::string>(values[1]), "43");
+    BOOST_CHECK_EQUAL(std::get<int>(values[2]), 44);
+
+    BOOST_CHECK_EQUAL(input.isFulfilled(), true);
+    BOOST_CHECK_EQUAL(output.isFulfilled(), true);
+
+    // auto p= new int;
+}
+
+BOOST_AUTO_TEST_CASE(ThenResolveAsync) {
+    std::thread thread;
+    auto promise = Promise<int>::resolve(42).then([&thread](int res) {
+        return Promise<std::string>{[&thread, res](const PromiseResolve<std::string> &resolve) {
+            thread = std::thread([resolve, res]() {
+                std::this_thread::sleep_for(std::chrono::milliseconds(1000));
+                std::ostringstream oss;
+                oss << "foo" << res;
+                resolve(oss.str());
+            });
+        }};
+    });
+
+    std::string value;
+    promise.then([&](const std::string &res) { value = res; }).wait();
+
+    static_assert((std::is_same_v<decltype(promise), Promise<std::string>>));
+    BOOST_CHECK_EQUAL(value, "foo42");
+    BOOST_CHECK_EQUAL(promise.isFulfilled(), true);
+
+    if (thread.joinable()) {
+        thread.join();
+    }
+}
+
+BOOST_AUTO_TEST_CASE(ThenRejectSync) {
+    auto input = Promise<int>::resolve(42);
+    auto output = input.then([](int res) {
+        std::ostringstream oss;
+        oss << "foo" << res;
+        throw oss.str();
+        return 42;
+    });
+
+    std::string error;
+    output.then([&](int res) { error += "bar" + std::to_string(res); }).fail([&](const std::string &err) { error += err; }).wait();
+
+    BOOST_CHECK_EQUAL(error, "foo42");
+    BOOST_CHECK_EQUAL(input.isFulfilled(), true);
+    BOOST_CHECK_EQUAL(output.isRejected(), true);
+}
+
+BOOST_AUTO_TEST_CASE(ThenRejectAsync) {
+    std::thread thread;
+    auto p = Promise<int>::resolve(42).then([&thread](int res) {
+        return Promise<void>{[&thread, res](const PromiseResolve<void> &, const PromiseReject<void> &reject) {
+            thread = std::thread([reject, res]() {
+                std::this_thread::sleep_for(std::chrono::milliseconds(1000));
+                std::ostringstream oss;
+                oss << "foo" << res;
+                reject(oss.str());
+            });
+        }};
+    });
+
+    static_assert((std::is_same_v<decltype(p), Promise<void>>));
+
+    std::string error;
+    p.fail([&](const std::string &err) { error = err; }).wait();
+
+    BOOST_CHECK_EQUAL(error, "foo42");
+    BOOST_CHECK_EQUAL(p.isRejected(), true);
+
+    if (thread.joinable()) {
+        thread.join();
+    }
+}
+
+BOOST_AUTO_TEST_CASE(ThenSkipResult) {
+    auto p = Promise<int>::resolve(42);
+
+    int value = -1;
+    p.then([&]() { value = 43; }).wait();
+
+    static_assert((std::is_same<decltype(p), Promise<int>>::value));
+    BOOST_CHECK_EQUAL(value, 43);
+}
+
+BOOST_AUTO_TEST_CASE(ThenNullHandler) {
+    { // resolved
+        auto p = Promise<int>::resolve(42).then(nullptr);
+
+        int value;
+        p.then([&](const int &res) { value = res; }).wait();
+
+        BOOST_CHECK_EQUAL(value, 42);
+        BOOST_CHECK_EQUAL(p.isFulfilled(), true);
+    }
+    { // rejected
+        auto p = Promise<int>::reject(std::string{"foo"}).then(nullptr);
+
+        std::string error;
+        p.fail([&](const std::string &err) {
+             error = err;
+             return 0;
+         }).wait();
+        BOOST_CHECK_EQUAL(error, "foo");
+        BOOST_CHECK_EQUAL(p.isRejected(), true);
+    }
+}
+
+const float kRes = 0.42f;
+const float kFail = -1.f;
+
+float fnNoArg() {
+    return kRes;
+}
+
+float fnArgByVal(float v) {
+    return v;
+}
+float fnArgByRef(const float &v) {
+    return v;
+}
+
+class Klass {
+public: // STATICS
+    static float kFnNoArg() {
+        return kRes;
+    }
+    static float kFnArgByVal(float v) {
+        return v;
+    }
+    static float kFnArgByRef(const float &v) {
+        return v;
+    }
+
+public:
+    Klass(float v) : m_v{v} {
+    }
+
+    float fnNoArg() const {
+        return m_v;
+    }
+    float fnArgByVal(float v) const {
+        return v + m_v;
+    }
+    float fnArgByRef(const float &v) const {
+        return v + m_v;
+    }
+
+private:
+    const float m_v;
+};
+
+BOOST_AUTO_TEST_CASE(ThenFunctionPtrHandlers) {
+    { // Global functions.
+        auto p0 = Promise<void>::resolve().then(&fnNoArg);
+        auto p1 = Promise<float>::resolve(kRes).then(&fnArgByVal);
+        auto p2 = Promise<float>::resolve(kRes).then(&fnArgByRef);
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+    { // Static member functions.
+        auto p0 = Promise<void>::resolve().then(&Klass::kFnNoArg);
+        auto p1 = Promise<float>::resolve(kRes).then(&Klass::kFnArgByVal);
+        auto p2 = Promise<float>::resolve(kRes).then(&Klass::kFnArgByRef);
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(ThenStdFunctionHandlers) {
+    { // lvalue.
+        std::function<float()> stdFnNoArg = fnNoArg;
+        std::function<float(float)> stdFnArgByVal = fnArgByVal;
+        std::function<float(const float &)> stdFnArgByRef = fnArgByRef;
+
+        auto p0 = Promise<void>::resolve().then(stdFnNoArg);
+        auto p1 = Promise<float>::resolve(kRes).then(stdFnArgByVal);
+        auto p2 = Promise<float>::resolve(kRes).then(stdFnArgByRef);
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+    { // const lvalue.
+        const std::function<float()> stdFnNoArg = fnNoArg;
+        const std::function<float(float)> stdFnArgByVal = fnArgByVal;
+        const std::function<float(const float &)> stdFnArgByRef = fnArgByRef;
+
+        auto p0 = Promise<void>::resolve().then(stdFnNoArg);
+        auto p1 = Promise<float>::resolve(kRes).then(stdFnArgByVal);
+        auto p2 = Promise<float>::resolve(kRes).then(stdFnArgByRef);
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+    { // rvalue.
+        auto p0 = Promise<void>::resolve().then(std::function<float()>{fnNoArg});
+        auto p1 = Promise<float>::resolve(kRes).then(std::function<float(float)>{fnArgByVal});
+        auto p2 = Promise<float>::resolve(kRes).then(std::function<float(const float &)>{fnArgByRef});
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(ThenStdBindHandlers) {
+    using namespace std::placeholders;
+
+    const float val{42.f};
+    const Klass obj{val};
+
+    const std::function<float()> bindNoArg = std::bind(&Klass::fnNoArg, &obj);
+    const std::function<float(float)> bindArgByVal = std::bind(&Klass::fnArgByVal, &obj, _1);
+    const std::function<float(const float &)> bindArgByRef = std::bind(&Klass::fnArgByRef, &obj, _1);
+
+    auto p0 = Promise<void>::resolve().then(bindNoArg);
+    auto p1 = Promise<float>::resolve(kRes).then(bindArgByVal);
+    auto p2 = Promise<float>::resolve(kRes).then(bindArgByRef);
+
+    BOOST_CHECK_EQUAL(waitForValue(p0, kFail), val);
+    BOOST_CHECK_EQUAL(waitForValue(p1, kFail), val + kRes);
+    BOOST_CHECK_EQUAL(waitForValue(p2, kFail), val + kRes);
+}
+
+BOOST_AUTO_TEST_CASE(ThenLambdaHandlers) {
+    { // lvalue.
+        auto lambdaNoArg = []() { return kRes; };
+        auto lambdaArgByVal = [](float v) { return v; };
+        auto lambdaArgByRef = [](const float &v) { return v; };
+
+        auto p0 = Promise<void>::resolve().then(lambdaNoArg);
+        auto p1 = Promise<float>::resolve(kRes).then(lambdaArgByVal);
+        auto p2 = Promise<float>::resolve(kRes).then(lambdaArgByRef);
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+    { // const lvalue.
+        const auto lambdaNoArg = []() { return kRes; };
+        const auto lambdaArgByVal = [](float v) { return v; };
+        const auto lambdaArgByRef = [](const float &v) { return v; };
+
+        auto p0 = Promise<void>::resolve().then(lambdaNoArg);
+        auto p1 = Promise<float>::resolve(kRes).then(lambdaArgByVal);
+        auto p2 = Promise<float>::resolve(kRes).then(lambdaArgByRef);
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+    { // rvalue.
+        auto p0 = Promise<void>::resolve().then([]() { return kRes; });
+        auto p1 = Promise<float>::resolve(kRes).then([](float v) { return v; });
+        auto p2 = Promise<float>::resolve(kRes).then([](const float &v) { return v; });
+
+        BOOST_CHECK_EQUAL(waitForValue(p0, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p1, kFail), kRes);
+        BOOST_CHECK_EQUAL(waitForValue(p2, kFail), kRes);
+    }
+}

Universal/FunctionTraits.h

@@ -121,8 +121,87 @@ class FunctionTraits : public FunctionTraits<decltype(&Callable::operator())> {}
 
 template <typename Function>
 typename FunctionTraits<std::decay_t<Function>>::StlFunctionType makeStlFunction(Function &&lambda) {
-    return static_cast<typename FunctionTraits<std::decay_t<Function>>::StlFunctionType>(
-        std::forward<Function>(lambda));
+    return static_cast<typename FunctionTraits<std::decay_t<Function>>::StlFunctionType>(std::forward<Function>(lambda));
 }
 
+template <typename T>
+using Unqualified = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
+
+/*!
+ * \struct HasCallOperator
+ * http://stackoverflow.com/a/5117641
+ */
+template <typename T>
+struct HasCallOperator {
+    template <typename U>
+    static char check(decltype(&U::operator(), char(0)));
+
+    template <typename U>
+    static char (&check(...))[2];
+
+    static const bool value = (sizeof(check<T>(0)) == 1);
+};
+
+/*!
+ * \struct ArgsOf
+ * http://stackoverflow.com/a/7943765
+ * http://stackoverflow.com/a/27885283
+ */
+template <typename... Args>
+struct ArgsTraits {
+    using types = std::tuple<Args...>;
+    using first = typename std::tuple_element<0, types>::type;
+    static const size_t count = std::tuple_size<types>::value;
+};
+
+template <>
+struct ArgsTraits<> {
+    using types = std::tuple<>;
+    using first = void;
+    static const size_t count = 0;
+};
+
+// Fallback implementation, including types (T) which are not functions but
+// also lambda with `auto` arguments, which are not covered but still valid
+// callbacks (see the QPromiseBase<T> template constructor).
+template <typename T, typename Enabled = void>
+struct ArgsOf : public ArgsTraits<> {};
+
+// Partial specialization for null function.
+template <>
+struct ArgsOf<std::nullptr_t> : public ArgsTraits<> {};
+
+// Partial specialization for type with a non-overloaded operator().
+// This applies to lambda, std::function but not to std::bind result.
+template <typename T>
+struct ArgsOf<T, typename std::enable_if<HasCallOperator<T>::value>::type> : public ArgsOf<decltype(&T::operator())> {};
+
+// Partial specialization to remove reference and rvalue (e.g. lambda, std::function, etc.).
+template <typename T>
+struct ArgsOf<T &> : public ArgsOf<T> {};
+
+template <typename T>
+struct ArgsOf<T &&> : public ArgsOf<T> {};
+
+// Partial specialization for function type.
+template <typename R, typename... Args>
+struct ArgsOf<R(Args...)> : public ArgsTraits<Args...> {};
+
+// Partial specialization for function pointer.
+template <typename R, typename... Args>
+struct ArgsOf<R (*)(Args...)> : public ArgsTraits<Args...> {};
+
+// Partial specialization for pointer-to-member-function (i.e. operator()'s).
+template <typename R, typename T, typename... Args>
+struct ArgsOf<R (T::*)(Args...)> : public ArgsTraits<Args...> {};
+
+template <typename R, typename T, typename... Args>
+struct ArgsOf<R (T::*)(Args...) const> : public ArgsTraits<Args...> {};
+
+template <typename R, typename T, typename... Args>
+struct ArgsOf<R (T::*)(Args...) volatile> : public ArgsTraits<Args...> {};
+
+template <typename R, typename T, typename... Args>
+struct ArgsOf<R (T::*)(Args...) const volatile> : public ArgsTraits<Args...> {};
+
 #endif // FUNCTIONTRAITS_H

Universal/Private/PromiseData.h

@@ -0,0 +1,183 @@
+#ifndef __PROMISEDATA_H__
+#define __PROMISEDATA_H__
+
+#include <cassert>
+#include <list>
+#include <memory>
+#include <mutex>
+
+template <typename T>
+class PromiseValue {
+public:
+    PromiseValue() {
+    }
+    PromiseValue(const T &data) : m_data(std::make_shared<T>(data)) {
+    }
+    PromiseValue(T &&data) : m_data(std::make_shared<T>(std::forward<T>(data))) {
+    }
+    bool isNull() const {
+        return m_data == nullptr;
+    }
+    const T &data() const {
+        return *m_data;
+    }
+
+private:
+    std::shared_ptr<T> m_data;
+};
+
+class PromiseError {
+public:
+    template <typename T>
+    PromiseError(const T &value) {
+        try {
+            throw value;
+        } catch (...) {
+            m_data = std::current_exception();
+        }
+    }
+
+    PromiseError() {
+    }
+    PromiseError(const std::exception_ptr &exception) : m_data{exception} {
+    }
+    void rethrow() const {
+        std::rethrow_exception(m_data);
+    }
+    bool isNull() const {
+        return m_data == nullptr;
+    }
+
+private:
+    std::exception_ptr m_data; // std::exception_ptr is already a shared pointer
+};
+
+template <typename T, typename F>
+class PromiseDataBase {
+public:
+    using Handler = std::function<F>;
+    using Catcher = std::function<void(const PromiseError &)>;
+
+    bool isFulfilled() const {
+        return !isPending() && m_error.isNull();
+    }
+    bool isRejected() const {
+        return !isPending() && !m_error.isNull();
+    }
+
+    bool isPending() const {
+        std::lock_guard locker{m_mutex};
+        return !m_settled;
+    }
+
+    void addHandler(std::function<F> handler) {
+        std::lock_guard locker{m_mutex};
+        m_handlers.push_back(std::move(handler));
+    }
+
+    void addCatcher(std::function<void(const PromiseError &)> catcher) {
+        std::lock_guard locker{m_mutex};
+        m_catchers.push_back(std::move(catcher));
+    }
+
+    template <typename E>
+    void reject(E &&error) {
+        assert(isPending());
+        assert(m_error.isNull());
+        m_error = PromiseError{std::forward<E>(error)};
+        setSettled();
+    }
+
+    const PromiseError &error() const {
+        assert(isRejected());
+        return m_error;
+    }
+
+    void dispatch() {
+        if (isPending()) {
+            return;
+        }
+
+        m_mutex.lock();
+        auto handlers = std::move(m_handlers);
+        auto catchers = std::move(m_catchers);
+        m_mutex.unlock();
+
+        if (m_error.isNull()) {
+            notify(handlers);
+            return;
+        }
+
+        PromiseError error = m_error;
+        assert(!error.isNull());
+
+        for (auto &catcher : catchers) {
+            catcher(error);
+        }
+    }
+
+protected:
+    virtual void notify(const std::list<Handler> &handlers) = 0;
+    void setSettled() {
+        std::lock_guard locker{m_mutex};
+        assert(!m_settled);
+        m_settled = true;
+    }
+    mutable std::mutex m_mutex;
+
+private:
+    bool m_settled = false;
+    std::list<Handler> m_handlers;
+    std::list<Catcher> m_catchers;
+    PromiseError m_error;
+};
+
+template <typename T>
+class PromiseData : public PromiseDataBase<T, void(const T &)> {
+    using Handler = typename PromiseDataBase<T, void(const T &)>::Handler;
+
+public:
+    template <typename V>
+    void resolve(V &&value) {
+        assert(this->isPending());
+        assert(m_value.isNull());
+        m_value = PromiseValue<T>{std::forward<V>(value)};
+        this->setSettled();
+    }
+
+    const PromiseValue<T> &value() const {
+        assert(this->isFulfilled());
+        return m_value;
+    }
+
+protected:
+    void notify(const std::list<Handler> &handlers) final {
+        PromiseValue<T> value = m_value;
+        assert(!value.isNull());
+        for (auto &handler : handlers) {
+            handler(value.data());
+        }
+    }
+
+private:
+    PromiseValue<T> m_value;
+};
+
+template <>
+class PromiseData<void> : public PromiseDataBase<void, void()> {
+    using Handler = PromiseDataBase<void, void()>::Handler;
+
+public:
+    void resolve() {
+        setSettled();
+    }
+
+protected:
+    void notify(const std::list<Handler> &handlers) {
+        for (const auto &handler : handlers) {
+            handler();
+        }
+    }
+};
+
+#endif // __PROMISEDATA_H__

Universal/Private/PromiseException.h

@@ -0,0 +1,10 @@
+#ifndef __PROMISEEXCEPTION_H__
+#define __PROMISEEXCEPTION_H__
+
+#include <exception>
+
+class PromiseUndefinedException : public std::exception {
+public:
+};
+
+#endif // __PROMISEEXCEPTION_H__

Universal/Private/PromiseHandler.h

@@ -0,0 +1,203 @@
+#ifndef __PROMISEHANDLER_H__
+#define __PROMISEHANDLER_H__
+
+#include "../FunctionTraits.h"
+#include <type_traits>
+#include <exception>
+#include "PromiseData.h"
+
+template <typename T>
+class Promise;
+
+template <typename T>
+struct PromiseDeduce {
+    using Type = Promise<T>;
+};
+
+template <typename T>
+struct PromiseDeduce<T &> : public PromiseDeduce<T> {};
+
+template <typename T>
+struct PromiseDeduce<const T> : public PromiseDeduce<T> {};
+
+template <typename T>
+struct PromiseDeduce<const volatile T> : public PromiseDeduce<T> {};
+
+template <typename T>
+struct PromiseDeduce<Promise<T>> : public PromiseDeduce<T> {};
+
+template <typename T>
+struct PromiseFulfill {
+    template <typename V, typename TResolve, typename TReject>
+    static void call(V &&value, const TResolve &resolve, const TReject &) {
+        resolve(std::forward<V>(value));
+    }
+};
+
+template <typename T>
+struct PromiseFulfill<Promise<T>> {
+    template <typename TResolve, typename TReject>
+    static void call(const Promise<T> &promise, const TResolve &resolve, const TReject &reject) {
+        if (promise.isFulfilled()) {
+            resolve(promise.m_d->value());
+        } else if (promise.isRejected()) {
+            reject(promise.m_d->error());
+        } else {
+            promise.then([=]() { resolve(promise.m_d->value()); },
+                         [=]() { // catch all
+                             reject(promise.m_d->error());
+                         });
+        }
+    }
+};
+
+template <>
+struct PromiseFulfill<Promise<void>> {
+    template <typename TPromise, typename TResolve, typename TReject>
+    static void call(const TPromise &promise, const TResolve &resolve, const TReject &reject) {
+        if (promise.isFulfilled()) {
+            resolve();
+        } else if (promise.isRejected()) {
+            reject(promise.m_d->error());
+        } else {
+            promise.then([=]() { resolve(); },
+                         [=]() { // catch all
+                             reject(promise.m_d->error());
+                         });
+        }
+    }
+};
+
+template <typename Result>
+struct PromiseDispatch {
+    template <typename Resolve, typename Reject, typename Functor, typename... Args>
+    static void call(const Resolve &resolve, const Reject &reject, Functor fn, Args &&...args) {
+        try {
+            PromiseFulfill<std::decay_t<Result>>::call(fn(std::forward<Args>(args)...), resolve, reject);
+        } catch (...) {
+            reject(std::current_exception());
+        }
+    }
+};
+
+template <>
+struct PromiseDispatch<void> {
+    template <typename Resolve, typename Reject, typename Functor, typename... Args>
+    static void call(const Resolve &resolve, const Reject &reject, Functor fn, Args &&...args) {
+        try {
+            fn(std::forward<Args>(args)...);
+            resolve();
+        } catch (...) {
+            reject(std::current_exception());
+        }
+    }
+};
+
+template <typename T, typename THandler, typename TArg = typename ArgsOf<THandler>::first>
+struct PromiseHandler {
+    using ResType = std::invoke_result_t<THandler, T>;
+    using PromiseType = typename PromiseDeduce<ResType>::Type;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void(const T &)> create(const THandler &handler, const TResolve &resolve, const TReject &reject) {
+        return [=](const T &value) { PromiseDispatch<ResType>::call(resolve, reject, handler, value); };
+    }
+};
+
+template <typename T, typename THandler>
+struct PromiseHandler<T, THandler, void> {
+    using ResType = std::invoke_result_t<THandler>;
+    using PromiseType = typename PromiseDeduce<ResType>::Type;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void(const T &)> create(const THandler &handler, const TResolve &resolve, const TReject &reject) {
+        return [=](const T &) { PromiseDispatch<ResType>::call(resolve, reject, handler); };
+    }
+};
+
+template <typename THandler>
+struct PromiseHandler<void, THandler, void> {
+    using ResType = std::invoke_result_t<THandler>;
+    using PromiseType = typename PromiseDeduce<ResType>::Type;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void()> create(const THandler &handler, const TResolve &resolve, const TReject &reject) {
+        return [=]() { PromiseDispatch<ResType>::call(resolve, reject, handler); };
+    }
+};
+
+template <typename T>
+struct PromiseHandler<T, std::nullptr_t, void> {
+    using PromiseType = Promise<T>;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void(const T &)> create(std::nullptr_t, const TResolve &resolve, const TReject &reject) {
+        return [=](const T &value) {
+            // 2.2.7.3. If onFulfilled is not a function and promise1 is fulfilled,
+            // promise2 must be fulfilled with the same value as promise1.
+            PromiseFulfill<T>::call(std::move(T(value)), resolve, reject);
+        };
+    }
+};
+
+template <>
+struct PromiseHandler<void, std::nullptr_t, void> {
+    using PromiseType = Promise<void>;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void()> create(std::nullptr_t, const TResolve &resolve, const TReject &) {
+        return [=]() {
+            // 2.2.7.3. If onFulfilled is not a function and promise1 is fulfilled,
+            // promise2 must be fulfilled with the same value as promise1.
+            resolve();
+        };
+    }
+};
+
+template <typename T, typename THandler, typename TArg = typename ArgsOf<THandler>::first>
+struct PromiseCatcher {
+    using ResType = std::invoke_result_t<THandler, TArg>;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void(const PromiseError &)> create(const THandler &handler, const TResolve &resolve, const TReject &reject) {
+        return [=](const PromiseError &error) {
+            try {
+                error.rethrow();
+            } catch (const TArg &argError) {
+                PromiseDispatch<ResType>::call(resolve, reject, handler, argError);
+            } catch (...) {
+                reject(std::current_exception());
+            }
+        };
+    }
+};
+
+template <typename T, typename THandler>
+struct PromiseCatcher<T, THandler, void> {
+    using ResType = typename std::invoke_result_t<THandler>;
+
+    template <typename TResolve, typename TReject>
+    static std::function<void(const PromiseError &)> create(const THandler &handler, const TResolve &resolve, const TReject &reject) {
+        return [=](const PromiseError &error) {
+            try {
+                error.rethrow();
+            } catch (...) {
+                PromiseDispatch<ResType>::call(resolve, reject, handler);
+            }
+        };
+    }
+};
+
+template <typename T>
+struct PromiseCatcher<T, std::nullptr_t, void> {
+    template <typename TResolve, typename TReject>
+    static std::function<void(const PromiseError &)> create(std::nullptr_t, const TResolve &, const TReject &reject) {
+        return [=](const PromiseError &error) {
+            // 2.2.7.4. If onRejected is not a function and promise1 is rejected,
+            // promise2 must be rejected with the same reason as promise1
+            reject(error);
+        };
+    }
+};
+
+#endif // __PROMISEHANDLER_H__

Universal/Private/PromiseResolver.h

@@ -0,0 +1,91 @@
+#ifndef __PROMISERESOLVER_H__
+#define __PROMISERESOLVER_H__
+
+#include "PromiseException.h"
+
+template <typename T>
+class Promise;
+
+template <typename T>
+class PromiseResolver {
+public:
+    PromiseResolver(Promise<T> promise) : m_d{promise.m_d} {
+    }
+
+    template <typename V>
+    void resolve(V &&value) {
+        if (m_d) {
+            assert(m_d->isPending());
+            m_d->resolve(std::forward<V>(value));
+            m_d->dispatch();
+        }
+    }
+
+    void resolve() {
+        if (m_d) {
+            assert(m_d->isPending());
+            m_d->resolve();
+            m_d->dispatch();
+        }
+    }
+
+    template <typename E>
+    void reject(E &&error) {
+        if (m_d) {
+            assert(m_d->isPending());
+            m_d->reject(std::forward<E>(error));
+            m_d->dispatch();
+        }
+    }
+
+    void reject() {
+        if (m_d) {
+            assert(m_d->isPending());
+            m_d->reject(PromiseUndefinedException{});
+            m_d->dispatch();
+        }
+    }
+
+private:
+    std::shared_ptr<PromiseData<T>> m_d;
+};
+
+template <typename T>
+class PromiseResolve {
+public:
+    PromiseResolve(PromiseResolver<T> resolver) : m_resolver{std::move(resolver)} {
+    }
+
+    template <typename V>
+    void operator()(V &&value) const {
+        m_resolver.resolve(std::forward<V>(value));
+    }
+
+    void operator()() const {
+        m_resolver.resolve();
+    }
+
+private:
+    mutable PromiseResolver<T> m_resolver;
+};
+
+template <typename T>
+class PromiseReject {
+public:
+    PromiseReject(PromiseResolver<T> resolver) : m_resolver{std::move(resolver)} {
+    }
+
+    template <typename E>
+    void operator()(E &&error) const {
+        m_resolver.reject(std::forward<E>(error));
+    }
+
+    void operator()() const {
+        m_resolver.reject();
+    }
+
+private:
+    mutable PromiseResolver<T> m_resolver;
+};
+
+#endif // __PROMISERESOLVER_H__

Universal/Promise.h

@@ -0,0 +1,134 @@
+#ifndef __PROMISE_H__
+#define __PROMISE_H__
+
+#include "Private/PromiseHandler.h"
+#include "Private/PromiseResolver.h"
+#include <thread>
+
+template <typename T>
+class Promise;
+
+template <typename T>
+class PromiseBase {
+    friend struct PromiseFulfill<Promise<T>>;
+
+public:
+    using Type = T;
+    template <typename F, typename std::enable_if<ArgsOf<F>::count == 1, int>::type = 0>
+    PromiseBase(F callback) : m_d{std::make_shared<PromiseData<T>>()} {
+        PromiseResolver<T> resolver{*this};
+        try {
+            callback(PromiseResolve<T>(resolver));
+        } catch (...) {
+            resolver.reject(std::current_exception());
+        }
+    }
+
+    template <typename F, typename std::enable_if<ArgsOf<F>::count != 1, int>::type = 0>
+    PromiseBase(F callback) : m_d{std::make_shared<PromiseData<T>>()} {
+        PromiseResolver<T> resolver{*this};
+        try {
+            callback(PromiseResolve<T>(resolver), PromiseReject<T>(resolver));
+        } catch (...) {
+            resolver.reject(std::current_exception());
+        }
+    }
+
+    PromiseBase(const PromiseBase<T> &other) : m_d{other.m_d} {
+    }
+    PromiseBase(const Promise<T> &other) : m_d{other.m_d} {
+    }
+    PromiseBase(PromiseBase<T> &&other) {
+        swap(other);
+    }
+
+    void swap(PromiseBase<T> &other) {
+        std::swap(m_d, other.m_d);
+    }
+
+    bool isFulfilled() const {
+        return m_d->isFulfilled();
+    }
+    bool isRejected() const {
+        return m_d->isRejected();
+    }
+    bool isPending() const {
+        return m_d->isPending();
+    }
+
+    template <typename TFulfilled, typename TRejected>
+    typename PromiseHandler<T, TFulfilled>::PromiseType then(const TFulfilled &fulfilled, const TRejected &rejected) const {
+        using PromiseType = typename PromiseHandler<T, TFulfilled>::PromiseType;
+
+        PromiseType next(
+            [&](const PromiseResolve<typename PromiseType::Type> &resolve, const PromiseReject<typename PromiseType::Type> &reject) {
+                m_d->addHandler(PromiseHandler<T, TFulfilled>::create(fulfilled, resolve, reject));
+                m_d->addCatcher(PromiseCatcher<T, TRejected>::create(rejected, resolve, reject));
+            });
+
+        if (!m_d->isPending()) {
+            m_d->dispatch();
+        }
+
+        return next;
+    }
+
+    template <typename TFulfilled>
+    typename PromiseHandler<T, TFulfilled>::PromiseType then(TFulfilled &&fulfilled) const {
+        return then(std::forward<TFulfilled>(fulfilled), nullptr);
+    }
+
+    template <typename TRejected>
+    typename PromiseHandler<T, std::nullptr_t>::PromiseType fail(TRejected &&rejected) const {
+        return then(nullptr, std::forward<TRejected>(rejected));
+    }
+
+    Promise<T> wait() const {
+        while (m_d->isPending()) {
+            std::this_thread::yield();
+        }
+        return *this;
+    }
+
+    template <typename E>
+    static Promise<T> reject(E &&error) {
+        return Promise<T>{[&](const PromiseResolve<T> &, const PromiseReject<T> &reject) { reject(std::forward<E>(error)); }};
+    }
+
+protected:
+    std::shared_ptr<PromiseData<T>> m_d;
+};
+
+template <typename T>
+class Promise : public PromiseBase<T> {
+    friend class PromiseResolver<T>;
+
+public:
+    template <typename F>
+    Promise(F &&resolver) : PromiseBase<T>(std::forward<F>(resolver)) {
+    }
+
+    static Promise<T> resolve(const T &value) {
+        return Promise<T>{[&](const PromiseResolve<T> &resolve) { resolve(value); }};
+    }
+};
+
+template <>
+class Promise<void> : public PromiseBase<void> {
+    friend class PromiseResolver<void>;
+
+public:
+    template <typename F>
+    Promise(F &&resolver) : PromiseBase<void>(std::forward<F>(resolver)) {
+    }
+
+public:
+    static Promise<void> resolve() {
+        return Promise<void>{[](const PromiseResolve<void> &resolve) { resolve(); }};
+    }
+
+private:
+    friend class PromiseBase<void>;
+};
+
+#endif // __PROMISE_H__

resource/deploy.sh

@@ -48,7 +48,7 @@ function cmake_scan() {
         -B ${build_path} \
         -DCMAKE_BUILD_TYPE=Debug \
         -DUNIT_TEST=ON \
-        -DBOOST_ROOT=${libraries_root}/boost_1_85_0 \
+        -DBOOST_ROOT=${libraries_root}/boost_1_86_0 \
         -DZeroMQ_ROOT=${libraries_root}/zeromq-4.3.4_debug \
         ${cmake_qt_parameters}
 }