- wip -

- wip -

.travis.yml

@@ -30,7 +30,3 @@ script:
 
 after_success:
   - bash <(curl -s https://codecov.io/bash) -f coverage.info
-
-
-# gitbook install .
-# gitbook build . dist/docs

docs/SUMMARY.md

@@ -11,6 +11,7 @@
   * [.isPending](qtpromise/qpromise/ispending.md)
   * [.isRejected](qtpromise/qpromise/isrejected.md)
   * [.tap](qtpromise/qpromise/tap.md)
+  * [.tapFail](qtpromise/qpromise/tapfail.md)
   * [.then](qtpromise/qpromise/then.md)
   * [.timeout](qtpromise/qpromise/timeout.md)
   * [.wait](qtpromise/qpromise/wait.md)

docs/qtpromise/api-reference.md

@@ -10,6 +10,7 @@
 * [`QPromise<T>::isPending`](qpromise/ispending.md)
 * [`QPromise<T>::isRejected`](qpromise/isrejected.md)
 * [`QPromise<T>::tap`](qpromise/tap.md)
+* [`QPromise<T>::tapFail`](qpromise/tapfail.md)
 * [`QPromise<T>::then`](qpromise/then.md)
 * [`QPromise<T>::timeout`](qpromise/timeout.md)
 * [`QPromise<T>::wait`](qpromise/wait.md)

docs/qtpromise/qpromise/all.md

@@ -4,7 +4,9 @@
 [static] QPromise<T>::all(Sequence<QPromise<T>> promises) -> QPromise<QVector<T>>
 ```
 
-Returns a `QPromise<QVector<T>>` that fulfills when **all** `promises` of (the same) type `T` have been fulfilled. The `output` value is a vector containing **all** the values of `promises`, in the same order. If any of the given `promises` fail, `output` immediately rejects with the error of the promise that rejected, whether or not the other promises are resolved.
+Returns a `QPromise<QVector<T>>` that fulfills when **all** `promises` of (the same) type `T` have been fulfilled. The `output` value is a vector containing all the values of `promises`, in the same order, i.e., at the respective positions to the original sequence, regardless of completion order.
+
+If any of the given `promises` fail, `output` immediately rejects with the error of the promise that rejected, whether or not the other promises are resolved.
 
 `Sequence` is any STL compatible container (eg. `QVector`, `QList`, `std::vector`, etc.)
 

docs/qtpromise/qpromise/tapfail.md

@@ -0,0 +1,21 @@
+## `QPromise<T>::tapFail`
+
+```
+QPromise<T>::tapFail(Function handler) -> QPromise<T>
+```
+
+This `handler` allows to observe errors of the `input` promise without handling them - similar to [`finally`](finally.md) but **only** called on rejections. The `output` promise has the same type as the `input` one but also the same value or error. However, if `handler` throws, `output` is rejected with the new exception.
+
+```cpp
+QPromise<int> input = {...}
+auto output = input.tapFail([](Error err) {
+    log(err);
+}).then([](int res) {
+    return process(res);
+}).fail([](Error err) {
+    handle(err);
+    return -1;
+});
+```
+
+If `handler` returns a promise (or QFuture), the `output` promise is delayed until the returned promise is resolved and under the same conditions: the delayed value is ignored, the error transmitted to the `output` promise.

src/qtpromise/qpromise.h

@@ -3,6 +3,7 @@
 
 // QtPromise
 #include "qpromise_p.h"
+#include "qpromiseerror.h"
 #include "qpromiseglobal.h"
 
 // Qt
@@ -22,6 +23,9 @@ public:
     template <typename F, typename std::enable_if<QtPromisePrivate::ArgsOf<F>::count != 1, int>::type = 0>
     inline QPromiseBase(F resolver);
 
+    template <typename U>
+    inline QPromiseBase(const QPromise<U>& other);
+
     QPromiseBase(const QPromiseBase<T>& other): m_d(other.m_d) {}
     QPromiseBase(const QPromise<T>& other): m_d(other.m_d) {}
     QPromiseBase(QPromiseBase<T>&& other) Q_DECL_NOEXCEPT { swap(other); }
@@ -59,6 +63,9 @@ public:
     template <typename THandler>
     inline QPromise<T> tap(THandler handler) const;
 
+    template <typename THandler>
+    inline QPromise<T> tapFail(THandler handler) const;
+
     template <typename E = QPromiseTimeoutException>
     inline QPromise<T> timeout(int msec, E&& error = E()) const;
 
@@ -70,11 +77,10 @@ public: // STATIC
     inline static QPromise<T> reject(E&& error);
 
 protected:
-    friend struct QtPromisePrivate::PromiseFulfill<QPromise<T> >;
-    friend class QPromiseResolve<T>;
-    friend class QPromiseReject<T>;
+    friend struct QtPromisePrivate::PromiseFulfill<QPromise<T>>;
+    friend class QtPromisePrivate::PromiseResolver<T>;
 
-    QExplicitlySharedDataPointer<QtPromisePrivate::PromiseData<T> > m_d;
+    QExplicitlySharedDataPointer<QtPromisePrivate::PromiseData<T>> m_d;
 };
 
 template <typename T>
@@ -86,11 +92,14 @@ public:
 
 public: // STATIC
     template <template <typename, typename...> class Sequence = QVector, typename ...Args>
-    inline static QPromise<QVector<T> > all(const Sequence<QPromise<T>, Args...>& promises);
+    inline static QPromise<QVector<T>> all(const Sequence<QPromise<T>, Args...>& promises);
 
     inline static QPromise<T> resolve(const T& value);
     inline static QPromise<T> resolve(T&& value);
 
+    template <typename U>
+    operator QPromise<U>();
+
 private:
     friend class QPromiseBase<T>;
 };
@@ -102,6 +111,9 @@ public:
     template <typename F>
     QPromise(F&& resolver): QPromiseBase<void>(std::forward<F>(resolver)) { }
 
+    template <typename T>
+    QPromise(const QPromise<T>& other);
+
 public: // STATIC
     template <template <typename, typename...> class Sequence = QVector, typename ...Args>
     inline static QPromise<void> all(const Sequence<QPromise<void>, Args...>& promises);

src/qtpromise/qpromise.inl

@@ -9,95 +9,82 @@ template <class T>
 class QPromiseResolve
 {
 public:
-    QPromiseResolve(QPromise<T> p)
-        : m_promise(new QPromise<T>(std::move(p)))
+    QPromiseResolve(QtPromisePrivate::PromiseResolver<T> resolver)
+        : m_resolver(std::move(resolver))
     { }
 
     template <typename V>
     void operator()(V&& value) const
     {
-        Q_ASSERT(!m_promise.isNull());
-        if (m_promise->isPending()) {
-            m_promise->m_d->resolve(std::forward<V>(value));
-            m_promise->m_d->dispatch();
-        }
+        m_resolver.resolve(std::forward<V>(value));
     }
 
-private:
-    QSharedPointer<QPromise<T> > m_promise;
-};
-
-template <>
-class QPromiseResolve<void>
-{
-public:
-    QPromiseResolve(QPromise<void> p)
-        : m_promise(new QPromise<void>(std::move(p)))
-    { }
-
     void operator()() const
     {
-        Q_ASSERT(!m_promise.isNull());
-        if (m_promise->isPending()) {
-            m_promise->m_d->resolve();
-            m_promise->m_d->dispatch();
-        }
+        m_resolver.resolve();
     }
 
 private:
-    QSharedPointer<QPromise<void> > m_promise;
+    mutable QtPromisePrivate::PromiseResolver<T> m_resolver;
 };
 
 template <class T>
 class QPromiseReject
 {
 public:
-    QPromiseReject(QPromise<T> p)
-        : m_promise(new QPromise<T>(std::move(p)))
+    QPromiseReject(QtPromisePrivate::PromiseResolver<T> resolver)
+        : m_resolver(std::move(resolver))
     { }
 
     template <typename E>
     void operator()(E&& error) const
     {
-        Q_ASSERT(!m_promise.isNull());
-        if (m_promise->isPending()) {
-            m_promise->m_d->reject(std::forward<E>(error));
-            m_promise->m_d->dispatch();
-        }
+        m_resolver.reject(std::forward<E>(error));
     }
 
 private:
-    QSharedPointer<QPromise<T> > m_promise;
+    mutable QtPromisePrivate::PromiseResolver<T> m_resolver;
 };
 
 template <typename T>
 template <typename F, typename std::enable_if<QtPromisePrivate::ArgsOf<F>::count == 1, int>::type>
-inline QPromiseBase<T>::QPromiseBase(F resolver)
+inline QPromiseBase<T>::QPromiseBase(F callback)
     : m_d(new QtPromisePrivate::PromiseData<T>())
 {
-    QPromiseResolve<T> resolve(*this);
-    QPromiseReject<T> reject(*this);
+    QtPromisePrivate::PromiseResolver<T> resolver(*this);
 
     try {
-        resolver(resolve);
+        callback(QPromiseResolve<T>(resolver));
     } catch (...) {
-        reject(std::current_exception());
+        resolver.reject(std::current_exception());
     }
 }
 
 template <typename T>
 template <typename F, typename std::enable_if<QtPromisePrivate::ArgsOf<F>::count != 1, int>::type>
-inline QPromiseBase<T>::QPromiseBase(F resolver)
+inline QPromiseBase<T>::QPromiseBase(F callback)
     : m_d(new QtPromisePrivate::PromiseData<T>())
 {
+    QtPromisePrivate::PromiseResolver<T> resolver(*this);
+
+    try {
+        callback(QPromiseResolve<T>(resolver), QPromiseReject<T>(resolver));
+    } catch (...) {
+        resolver.reject(std::current_exception());
+    }
+}
+
+template <typename T>
+template <typename U>
+inline QPromiseBase<T>::QPromiseBase(const QPromise<U>& other)
+    : m_d(new QtPromisePrivate::PromiseData<T>())
+{
+    using namespace QtPromisePrivate;
+
     QPromiseResolve<T> resolve(*this);
     QPromiseReject<T> reject(*this);
 
-    try {
-        resolver(resolve, reject);
-    } catch (...) {
-        reject(std::current_exception());
-    }
+    PromiseFulfill<QPromise<U> >::call(other, PromiseCast<U, T>::apply(resolve), reject);
 }
 
 template <typename T>
@@ -158,6 +145,16 @@ inline QPromise<T> QPromiseBase<T>::tap(THandler handler) const
     });
 }
 
+template <typename T>
+template <typename THandler>
+inline QPromise<T> QPromiseBase<T>::tapFail(THandler handler) const
+{
+    QPromise<T> p = *this;
+    return p.then([](){}, handler).then([=]() {
+        return p;
+    });
+}
+
 template <typename T>
 template <typename E>
 inline QPromise<T> QPromiseBase<T>::timeout(int msec, E&& error) const
@@ -174,7 +171,7 @@ inline QPromise<T> QPromiseBase<T>::timeout(int msec, E&& error) const
             reject(std::move(error));
         });
 
-        QtPromisePrivate::PromiseFulfill<QPromise<T> >::call(p, resolve, reject);
+        QtPromisePrivate::PromiseFulfill<QPromise<T>>::call(p, resolve, reject);
     });
 }
 
@@ -211,19 +208,19 @@ inline QPromise<T> QPromiseBase<T>::reject(E&& error)
 
 template <typename T>
 template <template <typename, typename...> class Sequence, typename ...Args>
-inline QPromise<QVector<T> > QPromise<T>::all(const Sequence<QPromise<T>, Args...>& promises)
+inline QPromise<QVector<T>> QPromise<T>::all(const Sequence<QPromise<T>, Args...>& promises)
 {
-    const int count = (int)promises.size();
+    const int count = static_cast<int>(promises.size());
     if (count == 0) {
-        return QPromise<QVector<T> >::resolve({});
+        return QPromise<QVector<T>>::resolve({});
     }
 
-    return QPromise<QVector<T> >([=](
-        const QPromiseResolve<QVector<T> >& resolve,
-        const QPromiseReject<QVector<T> >& reject) {
+    return QPromise<QVector<T>>([=](
+        const QPromiseResolve<QVector<T>>& resolve,
+        const QPromiseReject<QVector<T>>& reject) {
 
         QSharedPointer<int> remaining(new int(count));
-        QSharedPointer<QVector<T> > results(new QVector<T>(count));
+        QSharedPointer<QVector<T>> results(new QVector<T>(count));
 
         int i = 0;
         for (const auto& promise: promises) {
@@ -260,10 +257,25 @@ inline QPromise<T> QPromise<T>::resolve(T&& value)
     });
 }
 
+template <typename T>
+template <typename U>
+QPromise<T>::operator QPromise<U>()
+{
+    return QPromise<U>::resolve(U());
+}
+
+template <typename T>
+QPromise<void>::QPromise(const QPromise<T>& other)
+    : QPromiseBase<void>([&](const QPromiseResolve<void>& resolve, const QPromiseReject<void>& reject) {
+        QtPromisePrivate::PromiseFulfill<QPromise<T> >::call(other, resolve, reject);
+    })
+{
+}
+
 template <template <typename, typename...> class Sequence, typename ...Args>
 inline QPromise<void> QPromise<void>::all(const Sequence<QPromise<void>, Args...>& promises)
 {
-    const int count = (int)promises.size();
+    const int count = static_cast<int>(promises.size());
     if (count == 0) {
         return QPromise<void>::resolve();
     }

src/qtpromise/qpromise_p.h

@@ -2,7 +2,6 @@
 #define QTPROMISE_QPROMISE_P_H
 
 // QtPromise
-#include "qpromiseerror.h"
 #include "qpromiseglobal.h"
 
 // Qt
@@ -34,9 +33,10 @@ namespace QtPromisePrivate {
 template <typename F>
 static void qtpromise_defer(F&& f, const QPointer<QThread>& thread)
 {
+    using FType = typename std::decay<F>::type;
+
     struct Event : public QEvent
     {
-        using FType = typename std::decay<F>::type;
         Event(FType&& f) : QEvent(QEvent::None), m_f(std::move(f)) { }
         Event(const FType& f) : QEvent(QEvent::None), m_f(f) { }
         ~Event() { m_f(); }
@@ -72,35 +72,71 @@ static void qtpromise_defer(F&& f)
 }
 
 template <typename T>
-struct PromiseDeduce
+class PromiseValue
 {
-    using Type = QtPromise::QPromise<Unqualified<T> >;
+public:
+    PromiseValue() { }
+    PromiseValue(const T& data) : m_data(new T(data)) { }
+    PromiseValue(T&& data) : m_data(new T(std::move(data))) { }
+    bool isNull() const { return m_data.isNull(); }
+    const T& data() const { return *m_data; }
+
+private:
+    QSharedPointer<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:
+    // NOTE(SB) std::exception_ptr is already a shared pointer
+    std::exception_ptr m_data;
 };
 
 template <typename T>
-struct PromiseDeduce<QtPromise::QPromise<T> >
+struct PromiseDeduce
+{
+    using Type = QtPromise::QPromise<Unqualified<T>>;
+};
+
+template <typename T>
+struct PromiseDeduce<QtPromise::QPromise<T>>
     : public PromiseDeduce<T>
 { };
 
 template <typename T>
 struct PromiseFulfill
 {
-    static void call(
-        T&& value,
-        const QtPromise::QPromiseResolve<T>& resolve,
-        const QtPromise::QPromiseReject<T>&)
+    template <typename TResolve, typename TReject>
+    static void call(T&& value, const TResolve& resolve, const TReject&)
     {
         resolve(std::move(value));
     }
 };
 
 template <typename T>
-struct PromiseFulfill<QtPromise::QPromise<T> >
+struct PromiseFulfill<QtPromise::QPromise<T>>
 {
+    template <typename TResolve, typename TReject>
     static void call(
         const QtPromise::QPromise<T>& promise,
-        const QtPromise::QPromiseResolve<T>& resolve,
-        const QtPromise::QPromiseReject<T>& reject)
+        const TResolve& resolve,
+        const TReject& reject)
     {
         if (promise.isFulfilled()) {
             resolve(promise.m_d->value());
@@ -117,11 +153,11 @@ struct PromiseFulfill<QtPromise::QPromise<T> >
 };
 
 template <>
-struct PromiseFulfill<QtPromise::QPromise<void> >
+struct PromiseFulfill<QtPromise::QPromise<void>>
 {
-    template <typename TPromise, typename TResolve, typename TReject>
+    template <typename TResolve, typename TReject>
     static void call(
-        const TPromise& promise,
+        const QtPromise::QPromise<void>& promise,
         const TResolve& resolve,
         const TReject& reject)
     {
@@ -305,12 +341,12 @@ struct PromiseCatcher
     using ResType = typename std::result_of<THandler(TArg)>::type;
 
     template <typename TResolve, typename TReject>
-    static std::function<void(const QtPromise::QPromiseError&)> create(
+    static std::function<void(const PromiseError&)> create(
         const THandler& handler,
         const TResolve& resolve,
         const TReject& reject)
     {
-        return [=](const QtPromise::QPromiseError& error) {
+        return [=](const PromiseError& error) {
             try {
                 error.rethrow();
             } catch (const TArg& error) {
@@ -328,12 +364,12 @@ struct PromiseCatcher<T, THandler, void>
     using ResType = typename std::result_of<THandler()>::type;
 
     template <typename TResolve, typename TReject>
-    static std::function<void(const QtPromise::QPromiseError&)> create(
+    static std::function<void(const PromiseError&)> create(
         const THandler& handler,
         const TResolve& resolve,
         const TReject& reject)
     {
-        return [=](const QtPromise::QPromiseError& error) {
+        return [=](const PromiseError& error) {
             try {
                 error.rethrow();
             } catch (...) {
@@ -347,12 +383,12 @@ template <typename T>
 struct PromiseCatcher<T, std::nullptr_t, void>
 {
     template <typename TResolve, typename TReject>
-    static std::function<void(const QtPromise::QPromiseError&)> create(
+    static std::function<void(const PromiseError&)> create(
         std::nullptr_t,
         const TResolve&,
         const TReject& reject)
     {
-        return [=](const QtPromise::QPromiseError& error) {
+        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);
@@ -360,15 +396,75 @@ struct PromiseCatcher<T, std::nullptr_t, void>
     }
 };
 
+template <typename T, typename U>
+struct PromiseCast
+{
+    template <typename F>
+    static auto apply(const F& resolve)
+    {
+        return [=](const QSharedPointer<T>& value) {
+            resolve(static_cast<T>(*value));
+        };
+    }
+};
+
+template <typename T>
+struct PromiseCast<T, void>
+{
+    template <typename F>
+    static auto apply(const F& resolve)
+    {
+        return [=](const QSharedPointer<T>&) {
+            resolve();
+        };
+    }
+};
+
+/*
+template <typename T>
+struct PromiseCast<T, QVariant>
+{
+    static QtPromise::QPromise<QVariant> cast(
+        const QtPromise::QPromiseBase<T>& input)
+    {
+        return input.then([](const T& res) {
+            return QVariant::fromValue(res);
+        });
+    }
+};
+
+template <typename U>
+struct PromiseCast<QVariant, U>
+{
+    static QtPromise::QPromise<U> cast(
+        const QtPromise::QPromiseBase<QVariant>& input)
+    {
+        return input.then([](const QVariant& res) {
+            return res.value<U>();
+        });
+    }
+};
+
+template <>
+struct PromiseCast<void, QVariant>
+{
+    static QtPromise::QPromise<void> cast(
+        const QtPromise::QPromiseBase<QVariant>& input)
+    {
+        return input.then([]() {
+        });
+    }
+};
+*/
+
 template <typename T> class PromiseData;
 
 template <typename T, typename F>
 class PromiseDataBase : public QSharedData
 {
 public:
-    using Error = QtPromise::QPromiseError;
-    using Handler = std::pair<QPointer<QThread>, std::function<F> >;
-    using Catcher = std::pair<QPointer<QThread>, std::function<void(const Error&)> >;
+    using Handler = std::pair<QPointer<QThread>, std::function<F>>;
+    using Catcher = std::pair<QPointer<QThread>, std::function<void(const PromiseError&)>>;
 
     virtual ~PromiseDataBase() {}
 
@@ -394,29 +490,22 @@ public:
         m_handlers.append({QThread::currentThread(), std::move(handler)});
     }
 
-    void addCatcher(std::function<void(const Error&)> catcher)
+    void addCatcher(std::function<void(const PromiseError&)> catcher)
     {
         QWriteLocker lock(&m_lock);
         m_catchers.append({QThread::currentThread(), std::move(catcher)});
     }
 
-    void reject(Error error)
+    template <typename E>
+    void reject(E&& error)
     {
         Q_ASSERT(isPending());
         Q_ASSERT(m_error.isNull());
-        m_error.reset(new Error(std::move(error)));
+        m_error = PromiseError(std::forward<E>(error));
         setSettled();
     }
 
-    void reject(const QSharedPointer<Error>& error)
-    {
-        Q_ASSERT(isPending());
-        Q_ASSERT(m_error.isNull());
-        m_error = error;
-        this->setSettled();
-    }
-
-    const QSharedPointer<Error>& error() const
+    const PromiseError& error() const
     {
         Q_ASSERT(isRejected());
         return m_error;
@@ -445,13 +534,13 @@ public:
             return;
         }
 
-        QSharedPointer<Error> error = m_error;
+        PromiseError error(m_error);
         Q_ASSERT(!error.isNull());
 
         for (const auto& catcher: catchers) {
             const auto& fn = catcher.second;
             qtpromise_defer([=]() {
-                fn(*error);
+                fn(error);
             }, catcher.first);
         }
     }
@@ -472,7 +561,7 @@ private:
     bool m_settled = false;
     QVector<Handler> m_handlers;
     QVector<Catcher> m_catchers;
-    QSharedPointer<Error> m_error;
+    PromiseError m_error;
 };
 
 template <typename T>
@@ -481,31 +570,16 @@ class PromiseData : public PromiseDataBase<T, void(const T&)>
     using Handler = typename PromiseDataBase<T, void(const T&)>::Handler;
 
 public:
-    void resolve(T&& value)
+    template <typename V>
+    void resolve(V&& value)
     {
         Q_ASSERT(this->isPending());
         Q_ASSERT(m_value.isNull());
-        m_value.reset(new T(std::move(value)));
+        m_value = PromiseValue<T>(std::forward<V>(value));
         this->setSettled();
     }
 
-    void resolve(const T& value)
-    {
-        Q_ASSERT(this->isPending());
-        Q_ASSERT(m_value.isNull());
-        m_value.reset(new T(value));
-        this->setSettled();
-    }
-
-    void resolve(const QSharedPointer<T>& value)
-    {
-        Q_ASSERT(this->isPending());
-        Q_ASSERT(m_value.isNull());
-        m_value = value;
-        this->setSettled();
-    }
-
-    const QSharedPointer<T>& value() const
+    const PromiseValue<T>& value() const
     {
         Q_ASSERT(this->isFulfilled());
         return m_value;
@@ -513,19 +587,19 @@ public:
 
     void notify(const QVector<Handler>& handlers) Q_DECL_OVERRIDE
     {
-        QSharedPointer<T> value(m_value);
+        PromiseValue<T> value(m_value);
         Q_ASSERT(!value.isNull());
 
         for (const auto& handler: handlers) {
             const auto& fn = handler.second;
             qtpromise_defer([=]() {
-                fn(*value);
+                fn(value.data());
             }, handler.first);
         }
     }
 
 private:
-    QSharedPointer<T> m_value;
+    PromiseValue<T> m_value;
 };
 
 template <>
@@ -548,6 +622,68 @@ protected:
     }
 };
 
+template <typename T>
+class PromiseResolver
+{
+public:
+    PromiseResolver(QtPromise::QPromise<T> promise)
+        : m_d(new Data())
+    {
+        m_d->promise = new QtPromise::QPromise<T>(std::move(promise));
+    }
+
+    template <typename E>
+    void reject(E&& error)
+    {
+        auto promise = m_d->promise;
+        if (promise) {
+            Q_ASSERT(promise->isPending());
+            promise->m_d->reject(std::forward<E>(error));
+            promise->m_d->dispatch();
+            release();
+        }
+    }
+
+    template <typename V>
+    void resolve(V&& value)
+    {
+        auto promise = m_d->promise;
+        if (promise) {
+            Q_ASSERT(promise->isPending());
+            promise->m_d->resolve(std::forward<V>(value));
+            promise->m_d->dispatch();
+            release();
+        }
+    }
+
+    void resolve()
+    {
+        auto promise = m_d->promise;
+        if (promise) {
+            Q_ASSERT(promise->isPending());
+            promise->m_d->resolve();
+            promise->m_d->dispatch();
+            release();
+        }
+    }
+
+private:
+    struct Data : public QSharedData
+    {
+        QtPromise::QPromise<T>* promise = nullptr;
+    };
+
+    QExplicitlySharedDataPointer<Data> m_d;
+
+    void release()
+    {
+        Q_ASSERT(m_d->promise);
+        Q_ASSERT(!m_d->promise->isPending());
+        delete m_d->promise;
+        m_d->promise = nullptr;
+    }
+};
+
 } // namespace QtPromise
 
-#endif // ifndef QTPROMISE_QPROMISE_H
+#endif // ifndef QTPROMISE_QPROMISE_P_H

src/qtpromise/qpromiseerror.h

@@ -2,6 +2,7 @@
 #define QTPROMISE_QPROMISEERROR_H
 
 // QtPromise
+#include "qpromise_p.h"
 #include "qpromiseglobal.h"
 
 // Qt
@@ -9,53 +10,6 @@
 
 namespace QtPromise {
 
-class QPromiseError
-{
-public:
-    template <typename T>
-    QPromiseError(const T& value)
-    {
-        try {
-            throw value;
-        } catch (...) {
-            m_exception = std::current_exception();
-        }
-    }
-
-    QPromiseError(const std::exception_ptr& exception)
-        : m_exception(exception)
-    { }
-
-    QPromiseError(const QPromiseError& error)
-        : m_exception(error.m_exception)
-    { }
-
-    QPromiseError(QPromiseError&& other)
-        : m_exception(nullptr)
-    {
-        swap(other);
-    }
-
-    QPromiseError& operator=(QPromiseError other)
-    {
-        swap(other);
-        return *this;
-    }
-
-    void swap(QPromiseError& other)
-    {
-        qSwap(m_exception, other.m_exception);
-    }
-
-    void rethrow() const
-    {
-        std::rethrow_exception(m_exception);
-    }
-
-private:
-    std::exception_ptr m_exception;
-};
-
 class QPromiseTimeoutException : public QException
 {
 public:
@@ -66,6 +20,12 @@ public:
     }
 };
 
+// QPromiseError is provided for backward compatibility and will be
+// removed in the next major version: it wasn't intended to be used
+// directly and thus should not be part of the public API.
+// TODO Remove QPromiseError at version 1.0
+using QPromiseError = QtPromisePrivate::PromiseError;
+
 } // namespace QtPromise
 
 #endif // QTPROMISE_QPROMISEERROR_H

src/qtpromise/qpromisefuture.h

@@ -22,12 +22,12 @@ public:
 namespace QtPromisePrivate {
 
 template <typename T>
-struct PromiseDeduce<QFuture<T> >
+struct PromiseDeduce<QFuture<T>>
     : public PromiseDeduce<T>
 { };
 
 template <typename T>
-struct PromiseFulfill<QFuture<T> >
+struct PromiseFulfill<QFuture<T>>
 {
     static void call(
         const QFuture<T>& future,
@@ -62,7 +62,7 @@ struct PromiseFulfill<QFuture<T> >
 };
 
 template <>
-struct PromiseFulfill<QFuture<void> >
+struct PromiseFulfill<QFuture<void>>
 {
     static void call(
         const QFuture<void>& future,

src/qtpromise/qpromiseglobal.h

@@ -85,7 +85,7 @@ struct ArgsOf<TReturn(T::*)(Args...) const volatile> : public ArgsTraits<Args...
 { };
 
 template <typename T>
-struct ArgsOf<std::function<T> > : public ArgsOf<T>
+struct ArgsOf<std::function<T>> : public ArgsOf<T>
 { };
 
 template <typename T>

src/qtpromise/qpromisehelpers.h

@@ -27,7 +27,7 @@ static inline QPromise<void> qPromise()
 }
 
 template <typename T, template <typename, typename...> class Sequence = QVector, typename ...Args>
-static inline QPromise<QVector<T> > qPromiseAll(const Sequence<QPromise<T>, Args...>& promises)
+static inline QPromise<QVector<T>> qPromiseAll(const Sequence<QPromise<T>, Args...>& promises)
 {
     return QPromise<T>::all(promises);
 }

tests/auto/qtpromise/future/tst_future.cpp

@@ -56,7 +56,7 @@ void tst_future::fulfilled()
         return 42;
     }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(p.isPending(), true);
 
     p.then([&](int res) {
@@ -72,7 +72,7 @@ void tst_future::fulfilled_void()
     int result = -1;
     auto p = qPromise(QtConcurrent::run([]() { }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(p.isPending(), true);
 
     p.then([&]() {
@@ -91,7 +91,7 @@ void tst_future::rejected()
         return 42;
     }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(p.isPending(), true);
 
     p.fail([&](const MyException& e) {
@@ -110,7 +110,7 @@ void tst_future::rejected_void()
         throw MyException("foo");
     }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
 
     QCOMPARE(p.isPending(), true);
 
@@ -130,7 +130,7 @@ void tst_future::unhandled()
         return 42;
     }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
 
     QCOMPARE(p.isPending(), true);
 
@@ -153,7 +153,7 @@ void tst_future::unhandled_void()
         throw QString("foo");
     }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(p.isPending(), true);
 
     p.fail([&](const QString& err) {
@@ -307,7 +307,7 @@ void tst_future::finally()
         });
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(output), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(output), QPromise<int>>::value));
 
     QCOMPARE(input.isFulfilled(), true);
     QCOMPARE(output.isPending(), true);
@@ -330,7 +330,7 @@ void tst_future::finallyRejected()
         });
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(output), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(output), QPromise<int>>::value));
 
     QCOMPARE(input.isFulfilled(), true);
     QCOMPARE(output.isPending(), true);

tests/auto/qtpromise/helpers/tst_helpers.cpp

@@ -33,7 +33,7 @@ void tst_helpers::resolve()
     int value = -1;
     auto p = QtPromise::qPromise(42);
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
 
     QCOMPARE(p.isFulfilled(), true);
 
@@ -49,7 +49,7 @@ void tst_helpers::resolve_void()
     int value = -1;
     auto p = QtPromise::qPromise();
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
 
     QCOMPARE(p.isFulfilled(), true);
 
@@ -70,7 +70,7 @@ void tst_helpers::resolve_promise()
             });
         }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QString> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QString>>::value));
 
     QCOMPARE(p.isPending(), true);
 
@@ -93,7 +93,7 @@ void tst_helpers::resolve_promise_void()
             });
         }));
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
 
     QCOMPARE(p.isPending(), true);
 
@@ -115,9 +115,9 @@ void tst_helpers::allFulfilled()
         });
     });
 
-    auto p = qPromiseAll(QVector<QPromise<int> >{p0, p2, p1});
+    auto p = qPromiseAll(QVector<QPromise<int>>{p0, p2, p1});
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int> > >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int>>>::value));
 
     QCOMPARE(p.isPending(), true);
     QCOMPARE(p0.isFulfilled(), true);
@@ -144,9 +144,9 @@ void tst_helpers::allFulfilled_void()
         });
     });
 
-    auto p = qPromiseAll(QVector<QPromise<void> >{p0, p2, p1});
+    auto p = qPromiseAll(QVector<QPromise<void>>{p0, p2, p1});
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
 
     QCOMPARE(p.isPending(), true);
     QCOMPARE(p0.isFulfilled(), true);
@@ -169,9 +169,9 @@ void tst_helpers::allRejected()
         });
     });
 
-    auto p = qPromiseAll(QVector<QPromise<int> >{p0, p2, p1});
+    auto p = qPromiseAll(QVector<QPromise<int>>{p0, p2, p1});
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int> > >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int>>>::value));
 
     QCOMPARE(p.isPending(), true);
     QCOMPARE(p0.isFulfilled(), true);
@@ -199,9 +199,9 @@ void tst_helpers::allRejected_void()
         });
     });
 
-    auto p = qPromiseAll(QVector<QPromise<void> >{p0, p2, p1});
+    auto p = qPromiseAll(QVector<QPromise<void>>{p0, p2, p1});
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
 
     QCOMPARE(p.isPending(), true);
     QCOMPARE(p0.isFulfilled(), true);
@@ -220,9 +220,9 @@ void tst_helpers::allRejected_void()
 
 void tst_helpers::allEmpty()
 {
-    auto p = qPromiseAll(QVector<QPromise<int> >());
+    auto p = qPromiseAll(QVector<QPromise<int>>());
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int> > >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int>>>::value));
 
     QCOMPARE(p.isFulfilled(), true);
 
@@ -236,9 +236,9 @@ void tst_helpers::allEmpty()
 
 void tst_helpers::allEmpty_void()
 {
-    auto p = qPromiseAll(QVector<QPromise<void> >());
+    auto p = qPromiseAll(QVector<QPromise<void>>());
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
 
     QCOMPARE(p.isFulfilled(), true);
 }

tests/auto/qtpromise/qpromise/all/tst_all.cpp

@@ -31,7 +31,7 @@ struct SequenceTester
 };
 
 template <template <typename, typename...> class Sequence, typename ...Args>
-struct SequenceTester<Sequence<QPromise<int>, Args...> >
+struct SequenceTester<Sequence<QPromise<int>, Args...>>
 {
     static void exec()
     {
@@ -47,13 +47,13 @@ struct SequenceTester<Sequence<QPromise<int>, Args...> >
 
         auto p = QPromise<int>::all(promises);
 
-        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int> > >::value));
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int>>>::value));
         QCOMPARE(waitForValue(p, QVector<int>()), QVector<int>({42, 46, 43, 44}));
     }
 };
 
 template <template <typename, typename...> class Sequence, typename ...Args>
-struct SequenceTester<Sequence<QPromise<void>, Args...> >
+struct SequenceTester<Sequence<QPromise<void>, Args...>>
 {
     static void exec()
     {
@@ -69,7 +69,7 @@ struct SequenceTester<Sequence<QPromise<void>, Args...> >
 
         auto p = QPromise<void>::all(promises);
 
-        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
         QCOMPARE(waitForValue(p, -1, 42), 42);
     }
 };
@@ -78,26 +78,26 @@ struct SequenceTester<Sequence<QPromise<void>, Args...> >
 
 void tst_qpromise_all::qList()
 {
-    SequenceTester<QList<QPromise<int> > >::exec();
-    SequenceTester<QList<QPromise<void> > >::exec();
+    SequenceTester<QList<QPromise<int>>>::exec();
+    SequenceTester<QList<QPromise<void>>>::exec();
 }
 
 // QVector::push_back/append isn't supported since it requires a default
 // constructor (see https://github.com/simonbrunel/qtpromise/issues/3)
 //void tst_qpromise_all::qVector()
 //{
-//    SequenceTester<QVector<QPromise<int> > >::exec();
-//    SequenceTester<QVector<QPromise<void> > >::exec();
+//    SequenceTester<QVector<QPromise<int>>>::exec();
+//    SequenceTester<QVector<QPromise<void>>>::exec();
 //}
 
 void tst_qpromise_all::stdList()
 {
-    SequenceTester<std::list<QPromise<int> > >::exec();
-    SequenceTester<std::list<QPromise<void> > >::exec();
+    SequenceTester<std::list<QPromise<int>>>::exec();
+    SequenceTester<std::list<QPromise<void>>>::exec();
 }
 
 void tst_qpromise_all::stdVector()
 {
-    SequenceTester<std::vector<QPromise<int> > >::exec();
-    SequenceTester<std::vector<QPromise<void> > >::exec();
+    SequenceTester<std::vector<QPromise<int>>>::exec();
+    SequenceTester<std::vector<QPromise<void>>>::exec();
 }

tests/auto/qtpromise/qpromise/cast/cast.pro

@@ -0,0 +1,4 @@
+TARGET = tst_qpromise_cast
+SOURCES += $$PWD/tst_cast.cpp
+
+include(../../qtpromise.pri)

tests/auto/qtpromise/qpromise/cast/tst_cast.cpp

@@ -0,0 +1,135 @@
+// Tests
+#include "../../shared/utils.h"
+
+// QtPromise
+#include <QtPromise>
+
+// Qt
+#include <QtTest>
+
+using namespace QtPromise;
+
+class tst_qpromise_cast : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void typeToVoid();
+
+
+    //void castToVoidOperator();
+    //void typeToVariant();   // QPromise<T>.cast<QVariant>()
+    //void variantToType();
+    //void voidToVariant();   // QPromise<void>.cast<QVariant>()
+    //void variantToVoid();
+
+    //void jsonValueToJsonObject();
+};
+
+QTEST_MAIN(tst_qpromise_cast)
+#include "tst_cast.moc"
+
+void tst_qpromise_cast::typeToVoid()
+{
+    QPromise<void> p0 = QPromise<int>::resolve(42);
+    QPromise<void> p1 = QPromise<QString>::resolve(QString("foo"));
+    QVERIFY(p0.isFulfilled());
+    QVERIFY(p1.isFulfilled());
+}
+
+//void tst_qpromise_cast::castToVoidOperator()
+//{
+    //auto p0 = QPromise<int>::resolve(42);
+    //QPromise<double> p1(p0);
+    //QPromise<void> p2(p0);
+    //auto p4 = QPromise<QString>::resolve("foo");
+    //
+    //p0.then([](int res) { qDebug() << res; });
+    //p1.then([](double res) { qDebug() << res; });
+    //p2.then([]() { qDebug() << "done"; });
+    //
+    //foo().then([]() {
+    //    qDebug() << "done";
+    //}).wait();
+    //
+    //QPromise<QVariant>::all({p0, p1, p4}).then([](const QVector<QVariant>& res) {
+    //    qDebug() << "all done!" << res;
+    //}).wait();
+//}
+
+/*
+namespace {
+
+template <typename T, typename U>
+void test_qpromise_cast(const T& t, const U& u)
+{
+    auto p = QPromise<T>::resolve(t).cast<U>();
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<U> >::value));
+    QCOMPARE(waitForValue(p, U()), u);
+}
+
+template <typename U>
+void test_qpromise_cast(const U& u)
+{
+    auto p = QPromise<void>::resolve().cast<U>();
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<U> >::value));
+    QCOMPARE(waitForValue(p, U()), u);
+}
+
+} // anonymous namespace
+
+
+void tst_qpromise_cast::typeToVariant()
+{
+    test_qpromise_cast(42, QVariant(42));
+    test_qpromise_cast(4.2, QVariant(4.2));
+    test_qpromise_cast(true, QVariant(true));
+    test_qpromise_cast(QString("foo"), QVariant(QString("foo")));
+    test_qpromise_cast(QUrl("http://x.y.z"), QVariant(QUrl("http://x.y.z")));
+    test_qpromise_cast(QSize(128, 256), QVariant(QSize(128, 256)));
+    test_qpromise_cast(QDate(2018, 1, 1), QVariant(QDate(2018, 1, 1)));
+    test_qpromise_cast(QJsonValue("foo"), QVariant(QJsonValue("foo")));
+    test_qpromise_cast(QStringList{"foo", "bar"}, QVariant(QStringList{"foo", "bar"}));
+    test_qpromise_cast(QList<QVariant>{"foo", 42}, QVariant(QList<QVariant>{"foo", 42}));
+    test_qpromise_cast(QMap<QString, QVariant>{{"foo", 42}}, QVariant(QVariantMap{{"foo", 42}}));
+}
+
+void tst_qpromise_cast::voidToVariant()
+{
+    test_qpromise_cast(QVariant());
+}
+
+void tst_qpromise_cast::variantToType()
+{
+    // invalid
+    // int
+    // QString
+    // QColor
+    // QList
+}
+
+
+/*
+void tst_qpromise_cast::jsonValueToJsonObject()
+{
+    {   // QJsonValue(Null) -> QJsonObject
+        auto p = QPromise<QJsonValue>::resolve(QJsonValue()).cast<QJsonObject>();
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QJsonObject> >::value));
+        const QJsonObject res = waitForValue(p, QJsonObject());
+        QVERIFY(res.isEmpty());
+    }
+    {   // QJsonValue(int) -> QJsonObject
+        auto p = QPromise<QJsonValue>::resolve(QJsonValue(42)).cast<QJsonObject>();
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QJsonObject> >::value));
+        const QJsonObject res = waitForValue(p, QJsonObject());
+        QVERIFY(res.isEmpty());
+    }
+    {   // QJsonValue(QJsonObject) -> QJsonObject
+        const QJsonObject object{{"magic", 42}};
+        auto p = QPromise<QJsonValue>::resolve(QJsonValue(object)).cast<QJsonObject>();
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QJsonObject> >::value));
+        const QJsonObject res = waitForValue(p, QJsonObject());
+        QCOMPARE(res.value("magic"), 42);
+    }
+}
+*/

tests/auto/qtpromise/qpromise/construct/tst_construct.cpp

@@ -7,6 +7,9 @@
 // Qt
 #include <QtTest>
 
+// STL
+#include <memory>
+
 using namespace QtPromise;
 
 class tst_qpromise_construct : public QObject
@@ -30,6 +33,8 @@ private Q_SLOTS:
     void rejectSync_void();
     void rejectAsync();
     void rejectAsync_void();
+    void connectAndResolve();
+    void connectAndReject();
 };
 
 QTEST_MAIN(tst_qpromise_construct)
@@ -228,3 +233,77 @@ void tst_qpromise_construct::rejectThrowTwoArgs_void()
     QCOMPARE(waitForValue(p, -1, 42), -1);
     QCOMPARE(waitForError(p, QString()), QString("foo"));
 }
+
+// https://github.com/simonbrunel/qtpromise/issues/6
+void tst_qpromise_construct::connectAndResolve()
+{
+    QScopedPointer<QObject> object(new QObject());
+
+    std::weak_ptr<int> wptr;
+
+    {
+        auto p = QPromise<std::shared_ptr<int>>([&](
+            const QPromiseResolve<std::shared_ptr<int>>& resolve,
+            const QPromiseReject<std::shared_ptr<int>>& reject) {
+
+            connect(object.data(), &QObject::objectNameChanged,
+                [=, &wptr](const QString& name) {
+                    std::shared_ptr<int> sptr(new int(42));
+
+                    wptr = sptr;
+
+                    if (name == "foobar") {
+                        resolve(sptr);
+                    } else {
+                        reject(42);
+                    }
+                });
+        });
+
+        QCOMPARE(p.isPending(), true);
+
+        object->setObjectName("foobar");
+
+        QCOMPARE(waitForValue(p, std::shared_ptr<int>()), wptr.lock());
+        QCOMPARE(wptr.use_count(), 1l); // "p" still holds a reference
+    }
+
+    QCOMPARE(wptr.use_count(), 0l);
+}
+
+// https://github.com/simonbrunel/qtpromise/issues/6
+void tst_qpromise_construct::connectAndReject()
+{
+    QScopedPointer<QObject> object(new QObject());
+
+    std::weak_ptr<int> wptr;
+
+    {
+        auto p = QPromise<int>([&](
+            const QPromiseResolve<int>& resolve,
+            const QPromiseReject<int>& reject) {
+
+            connect(object.data(), &QObject::objectNameChanged,
+                [=, &wptr](const QString& name) {
+                    std::shared_ptr<int> sptr(new int(42));
+
+                    wptr = sptr;
+
+                    if (name == "foobar") {
+                        reject(sptr);
+                    } else {
+                        resolve(42);
+                    }
+                });
+        });
+
+        QCOMPARE(p.isPending(), true);
+
+        object->setObjectName("foobar");
+
+        QCOMPARE(waitForError(p, std::shared_ptr<int>()), wptr.lock());
+        QCOMPARE(wptr.use_count(), 1l); // "p" still holds a reference
+    }
+
+    QCOMPARE(wptr.use_count(), 0l);
+}

tests/auto/qtpromise/qpromise/finally/tst_finally.cpp

@@ -39,7 +39,7 @@ void tst_qpromise_finally::fulfilledSync()
         return 16; // ignored!
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(waitForValue(p, -1), 42);
     QCOMPARE(p.isFulfilled(), true);
     QCOMPARE(value, 8);
@@ -53,7 +53,7 @@ void tst_qpromise_finally::fulfilledSync_void()
         return 16; // ignored!
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(waitForValue(p, -1, 42), 42);
     QCOMPARE(p.isFulfilled(), true);
     QCOMPARE(value, 8);
@@ -65,7 +65,7 @@ void tst_qpromise_finally::fulfilledThrows()
         throw QString("bar");
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(waitForError(p, QString()), QString("bar"));
     QCOMPARE(p.isRejected(), true);
 }
@@ -76,7 +76,7 @@ void tst_qpromise_finally::fulfilledThrows_void()
         throw QString("bar");
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(waitForError(p, QString()), QString("bar"));
     QCOMPARE(p.isRejected(), true);
 }
@@ -123,7 +123,7 @@ void tst_qpromise_finally::rejectedSync()
         return 16; // ignored!
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(waitForError(p, QString()), QString("foo"));
     QCOMPARE(p.isRejected(), true);
     QCOMPARE(value, 8);
@@ -137,7 +137,7 @@ void tst_qpromise_finally::rejectedSync_void()
         return 16; // ignored!
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(waitForError(p, QString()), QString("foo"));
     QCOMPARE(p.isRejected(), true);
     QCOMPARE(value, 8);
@@ -149,7 +149,7 @@ void tst_qpromise_finally::rejectedThrows()
         throw QString("bar");
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(waitForError(p, QString()), QString("bar"));
     QCOMPARE(p.isRejected(), true);
 }
@@ -160,7 +160,7 @@ void tst_qpromise_finally::rejectedThrows_void()
         throw QString("bar");
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(waitForError(p, QString()), QString("bar"));
     QCOMPARE(p.isRejected(), true);
 }

tests/auto/qtpromise/qpromise/qpromise.pro

@@ -1,12 +1,15 @@
 TEMPLATE = subdirs
 SUBDIRS += \
     all \
+    cast \
     construct \
     delay \
     fail \
     finally \
     operators \
+    reject \
     resolve \
     tap \
+    tapfail \
     then \
     timeout

tests/auto/qtpromise/qpromise/reject/reject.pro

@@ -0,0 +1,4 @@
+TARGET = tst_qpromise_reject
+SOURCES += $$PWD/tst_reject.cpp
+
+include(../../qtpromise.pri)

tests/auto/qtpromise/qpromise/reject/tst_reject.cpp

@@ -0,0 +1,74 @@
+// Tests
+#include "../../shared/utils.h"
+
+// QtPromise
+#include <QtPromise>
+
+// Qt
+#include <QtTest>
+
+// STL
+#include <memory>
+
+using namespace QtPromise;
+
+class tst_qpromise_reject : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void rejectWithValue();
+    void rejectWithQSharedPtr();
+    void rejectWithStdSharedPtr();
+};
+
+QTEST_MAIN(tst_qpromise_reject)
+#include "tst_reject.moc"
+
+void tst_qpromise_reject::rejectWithValue()
+{
+    auto p = QPromise<int>::reject(42);
+
+    QCOMPARE(p.isRejected(), true);
+    QCOMPARE(waitForError(p, -1), 42);
+}
+
+// https://github.com/simonbrunel/qtpromise/issues/6
+void tst_qpromise_reject::rejectWithQSharedPtr()
+{
+    QWeakPointer<int> wptr;
+
+    {
+        QSharedPointer<int> sptr(new int(42));
+        auto p = QPromise<int>::reject(sptr);
+
+        QCOMPARE(waitForError(p, QSharedPointer<int>()), sptr);
+
+        wptr = sptr;
+        sptr.reset();
+
+        QCOMPARE(wptr.isNull(), false); // "p" still holds a reference
+    }
+
+    QCOMPARE(wptr.isNull(), true);
+}
+
+// https://github.com/simonbrunel/qtpromise/issues/6
+void tst_qpromise_reject::rejectWithStdSharedPtr()
+{
+    std::weak_ptr<int> wptr;
+
+    {
+        std::shared_ptr<int> sptr(new int(42));
+        auto p = QPromise<int>::reject(sptr);
+
+        QCOMPARE(waitForError(p, std::shared_ptr<int>()), sptr);
+
+        wptr = sptr;
+        sptr.reset();
+
+        QCOMPARE(wptr.use_count(), 1l); // "p" still holds a reference
+    }
+
+    QCOMPARE(wptr.use_count(), 0l);
+}

tests/auto/qtpromise/qpromise/resolve/tst_resolve.cpp

@@ -7,6 +7,9 @@
 // Qt
 #include <QtTest>
 
+// STL
+#include <memory>
+
 using namespace QtPromise;
 
 class tst_qpromise_resolve : public QObject
@@ -14,14 +17,16 @@ class tst_qpromise_resolve : public QObject
     Q_OBJECT
 
 private Q_SLOTS:
-    void value();
-    void empty_void();
+    void resolveWithValue();
+    void resolveWithNoValue();
+    void resolveWithQSharedPtr();
+    void resolveWithStdSharedPtr();
 };
 
 QTEST_MAIN(tst_qpromise_resolve)
 #include "tst_resolve.moc"
 
-void tst_qpromise_resolve::value()
+void tst_qpromise_resolve::resolveWithValue()
 {
     const int value = 42;
     auto p0 = QPromise<int>::resolve(value);
@@ -33,9 +38,49 @@ void tst_qpromise_resolve::value()
     QCOMPARE(waitForValue(p1, -1), 43);
 }
 
-void tst_qpromise_resolve::empty_void()
+void tst_qpromise_resolve::resolveWithNoValue()
 {
     auto p = QPromise<void>::resolve();
 
     QCOMPARE(p.isFulfilled(), true);
 }
+
+// https://github.com/simonbrunel/qtpromise/issues/6
+void tst_qpromise_resolve::resolveWithQSharedPtr()
+{
+    QWeakPointer<int> wptr;
+
+    {
+        QSharedPointer<int> sptr(new int(42));
+        auto p = QPromise<QSharedPointer<int>>::resolve(sptr);
+
+        QCOMPARE(waitForValue(p, QSharedPointer<int>()), sptr);
+
+        wptr = sptr;
+        sptr.reset();
+
+        QCOMPARE(wptr.isNull(), false); // "p" still holds a reference
+    }
+
+    QCOMPARE(wptr.isNull(), true);
+}
+
+// https://github.com/simonbrunel/qtpromise/issues/6
+void tst_qpromise_resolve::resolveWithStdSharedPtr()
+{
+    std::weak_ptr<int> wptr;
+
+    {
+        std::shared_ptr<int> sptr(new int(42));
+        auto p = QPromise<std::shared_ptr<int>>::resolve(sptr);
+
+        QCOMPARE(waitForValue(p, std::shared_ptr<int>()), sptr);
+
+        wptr = sptr;
+        sptr.reset();
+
+        QCOMPARE(wptr.use_count(), 1l); // "p" still holds a reference
+    }
+
+    QCOMPARE(wptr.use_count(), 0l);
+}

tests/auto/qtpromise/qpromise/tapfail/tapfail.pro

@@ -0,0 +1,4 @@
+TARGET = tst_qpromise_tapfail
+SOURCES += $$PWD/tst_tapfail.cpp
+
+include(../../qtpromise.pri)

tests/auto/qtpromise/qpromise/tapfail/tst_tapfail.cpp

@@ -0,0 +1,159 @@
+// Tests
+#include "../../shared/utils.h"
+
+// QtPromise
+#include <QtPromise>
+
+// Qt
+#include <QtTest>
+
+using namespace QtPromise;
+
+class tst_qpromise_tapfail : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void fulfilled();
+    void fulfilled_void();
+    void rejected();
+    void rejected_void();
+    void throws();
+    void throws_void();
+    void delayedResolved();
+    void delayedRejected();
+};
+
+QTEST_MAIN(tst_qpromise_tapfail)
+#include "tst_tapfail.moc"
+
+void tst_qpromise_tapfail::fulfilled()
+{
+    int value = -1;
+    auto p = QPromise<int>::resolve(42).tapFail([&]() {
+        value = 43;
+    });
+
+    QCOMPARE(waitForValue(p, 42), 42);
+    QCOMPARE(p.isFulfilled(), true);
+    QCOMPARE(value, -1);
+}
+
+void tst_qpromise_tapfail::fulfilled_void()
+{
+    int value = -1;
+    auto p = QPromise<void>::resolve().tapFail([&]() {
+        value = 43;
+    });
+
+    QCOMPARE(waitForValue(p, -1, 42), 42);
+    QCOMPARE(p.isFulfilled(), true);
+    QCOMPARE(value, -1);
+}
+
+void tst_qpromise_tapfail::rejected()
+{
+    QStringList errors;
+
+    auto p0 = QPromise<int>::reject(QString("foo"))
+        .tapFail([&](const QString& err) {
+            errors << "1:" + err;
+        });
+
+    auto p1 = p0
+        .fail([&](const QString& err) {
+            errors << "2:" + err;
+            return 43;
+        });
+
+    QCOMPARE(waitForError(p0, QString()), QString("foo"));
+    QCOMPARE(waitForValue(p1, -1), 43);
+    QCOMPARE(p0.isRejected(), true);
+    QCOMPARE(p1.isFulfilled(), true);
+    QCOMPARE(errors, QStringList() << "1:foo" << "2:foo");
+}
+
+void tst_qpromise_tapfail::rejected_void()
+{
+    QStringList errors;
+
+    auto p0 = QPromise<void>::reject(QString("foo"))
+        .tapFail([&](const QString& err) {
+            errors << "1:" + err;
+        });
+
+    auto p1 = p0
+        .fail([&](const QString& err) {
+            errors << "2:" + err;
+        });
+
+    QCOMPARE(waitForError(p0, QString()), QString("foo"));
+    QCOMPARE(waitForValue(p1, -1, 43), 43);
+    QCOMPARE(p0.isRejected(), true);
+    QCOMPARE(p1.isFulfilled(), true);
+    QCOMPARE(errors, QStringList() << "1:foo" << "2:foo");
+}
+
+void tst_qpromise_tapfail::throws()
+{
+    auto p = QPromise<int>::reject(QString("foo"))
+        .tapFail([&]() {
+            throw QString("bar");
+        });
+
+    QCOMPARE(waitForError(p, QString()), QString("bar"));
+    QCOMPARE(p.isRejected(), true);
+}
+
+void tst_qpromise_tapfail::throws_void()
+{
+    auto p = QPromise<void>::reject(QString("foo"))
+        .tapFail([&]() {
+            throw QString("bar");
+        });
+
+    QCOMPARE(waitForError(p, QString()), QString("bar"));
+    QCOMPARE(p.isRejected(), true);
+}
+
+void tst_qpromise_tapfail::delayedResolved()
+{
+    QVector<int> values;
+    auto p = QPromise<int>::reject(QString("foo"))
+        .tapFail([&]() {
+            QPromise<void> p([&](const QPromiseResolve<void>& resolve) {
+                    QtPromisePrivate::qtpromise_defer([=, &values]() {
+                        values << 3;
+                        resolve(); // ignored!
+                    });
+                });
+
+            values << 2;
+            return p;
+        });
+
+    QCOMPARE(waitForError(p, QString()), QString("foo"));
+    QCOMPARE(values, QVector<int>({2, 3}));
+}
+
+void tst_qpromise_tapfail::delayedRejected()
+{
+    QVector<int> values;
+    auto p = QPromise<int>::reject(QString("foo"))
+        .tapFail([&]() {
+            QPromise<void> p([&](
+                const QPromiseResolve<void>&,
+                const QPromiseReject<void>& reject){
+                    QtPromisePrivate::qtpromise_defer([=, &values]() {
+                        values << 3;
+                        reject(QString("bar"));
+                    });
+                });
+
+            values << 2;
+            return p;
+        });
+
+    QCOMPARE(waitForError(p, QString()), QString("bar"));
+    QCOMPARE(values, QVector<int>({2, 3}));
+}

tests/auto/qtpromise/qpromise/then/tst_then.cpp

@@ -56,7 +56,7 @@ void tst_qpromise_then::resolveAsync()
         });
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QString> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QString>>::value));
     QCOMPARE(waitForValue(p, QString()), QString("foo42"));
     QCOMPARE(p.isFulfilled(), true);
 }
@@ -91,7 +91,7 @@ void tst_qpromise_then::rejectAsync()
         });
     });
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void>>::value));
     QCOMPARE(waitForError(p, QString()), QString("foo42"));
     QCOMPARE(p.isRejected(), true);
 }
@@ -105,7 +105,7 @@ void tst_qpromise_then::skipResult()
         value = 43;
     }).wait();
 
-    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int> >::value));
+    Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<int>>::value));
     QCOMPARE(value, 43);
 }
 

tests/auto/qtpromise/qtpromise.pri

@@ -1,10 +1,15 @@
 TEMPLATE = app
-CONFIG += testcase
+CONFIG += testcase warn_on
 QT += testlib
 QT -= gui
 
 DEFINES += QT_DEPRECATED_WARNINGS
 
+# Additional warnings and make all warnings into errors
+# https://github.com/simonbrunel/qtpromise/issues/10
+gcc:QMAKE_CXXFLAGS += -Werror -Wold-style-cast
+msvc:QMAKE_CXXFLAGS -= -WX
+
 coverage {
     gcc {
         message("Code coverage enabled (gcov)")

tests/auto/qtpromise/requirements/tst_requirements.cpp

@@ -279,7 +279,7 @@ void tst_requirements::thenMultipleCalls()
             });
         });
 
-        qPromiseAll(QVector<QPromise<void> >{
+        qPromiseAll(QVector<QPromise<void>>{
             p.then([&](int r) { values << r + 1; }),
             p.then([&](int r) { values << r + 2; }),
             p.then([&](int r) { values << r + 3; })
@@ -298,7 +298,7 @@ void tst_requirements::thenMultipleCalls()
             });
         });
 
-        qPromiseAll(QVector<QPromise<int> >{
+        qPromiseAll(QVector<QPromise<int>>{
             p.then(nullptr, [&](int r) { values << r + 1; return r + 1; }),
             p.then(nullptr, [&](int r) { values << r + 2; return r + 2; }),
             p.then(nullptr, [&](int r) { values << r + 3; return r + 3; })
@@ -314,9 +314,9 @@ void tst_requirements::thenHandlers()
     {
         auto handler = [](){ return 42; };
         auto p1 = QPromise<int>::resolve(42);
-        Q_STATIC_ASSERT((std::is_same<decltype(p1.then(handler, nullptr)), QPromise<int> >::value));
-        Q_STATIC_ASSERT((std::is_same<decltype(p1.then(nullptr, handler)), QPromise<int> >::value));
-        Q_STATIC_ASSERT((std::is_same<decltype(p1.then(handler, handler)), QPromise<int> >::value));
+        Q_STATIC_ASSERT((std::is_same<decltype(p1.then(handler, nullptr)), QPromise<int>>::value));
+        Q_STATIC_ASSERT((std::is_same<decltype(p1.then(nullptr, handler)), QPromise<int>>::value));
+        Q_STATIC_ASSERT((std::is_same<decltype(p1.then(handler, handler)), QPromise<int>>::value));
     }
 
     // 2.2.7.1. If either onFulfilled or onRejected returns a value x, run the
@@ -351,7 +351,7 @@ void tst_requirements::thenHandlers()
         QString value;
         auto p1 = QPromise<QString>::resolve("42");
         auto p2 = p1.then(nullptr, [](){ return QString(); });
-        Q_STATIC_ASSERT((std::is_same<decltype(p2), QPromise<QString> >::value));
+        Q_STATIC_ASSERT((std::is_same<decltype(p2), QPromise<QString>>::value));
         p2.then([&](const QString& e) { value = e; }).wait();
 
         QVERIFY(p1.isFulfilled());

tests/auto/qtpromise/thread/tst_thread.cpp

@@ -28,159 +28,159 @@ QTEST_MAIN(tst_thread)
 void tst_thread::resolve()
 {
     int value = -1;
-    size_t target = 0;
-    size_t source = 0;
+    QThread* target = nullptr;
+    QThread* source = nullptr;
 
     QPromise<int>([&](const QPromiseResolve<int>& resolve) {
         QtConcurrent::run([=, &source]() {
-            source = (size_t)QThread::currentThread();
+            source = QThread::currentThread();
             resolve(42);
         });
     }).then([&](int res) {
-        target = (size_t)QThread::currentThread();
+        target = QThread::currentThread();
         value = res;
     }).wait();
 
-    QVERIFY(source != 0);
+    QVERIFY(source != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(target, (size_t)QThread::currentThread());
+    QCOMPARE(target, QThread::currentThread());
     QCOMPARE(value, 42);
 }
 
 void tst_thread::resolve_void()
 {
     int value = -1;
-    size_t target = 0;
-    size_t source = 0;
+    QThread* target = nullptr;
+    QThread* source = nullptr;
 
     QPromise<void>([&](const QPromiseResolve<void>& resolve) {
         QtConcurrent::run([=, &source]() {
-            source = (size_t)QThread::currentThread();
+            source = QThread::currentThread();
             resolve();
         });
     }).then([&]() {
-        target = (size_t)QThread::currentThread();
+        target = QThread::currentThread();
         value = 43;
     }).wait();
 
-    QVERIFY(source != 0);
+    QVERIFY(source != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(target, (size_t)QThread::currentThread());
+    QCOMPARE(target, QThread::currentThread());
     QCOMPARE(value, 43);
 }
 
 void tst_thread::reject()
 {
     QString error;
-    size_t target = 0;
-    size_t source = 0;
+    QThread* target = nullptr;
+    QThread* source = nullptr;
 
     QPromise<int>([&](const QPromiseResolve<int>&, const QPromiseReject<int>& reject) {
         QtConcurrent::run([=, &source]() {
-            source = (size_t)QThread::currentThread();
+            source = QThread::currentThread();
             reject(QString("foo"));
         });
     }).fail([&](const QString& err) {
-        target = (size_t)QThread::currentThread();
+        target = QThread::currentThread();
         error = err;
         return -1;
     }).wait();
 
-    QVERIFY(source != 0);
+    QVERIFY(source != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(target, (size_t)QThread::currentThread());
+    QCOMPARE(target, QThread::currentThread());
     QCOMPARE(error, QString("foo"));
 }
 
 void tst_thread::then()
 {
-    size_t source;
+    QThread* source = nullptr;
     QPromise<int> p([&](const QPromiseResolve<int>& resolve) {
-        source = (size_t)QThread::currentThread();
+        source = QThread::currentThread();
         resolve(42);
     });
 
-    size_t target;
     int value = -1;
+    QThread* target = nullptr;
     qPromise(QtConcurrent::run([&](const QPromise<int>& p) {
         p.then([&](int res) {
-            target = (size_t)QThread::currentThread();
+            target = QThread::currentThread();
             value = res;
         }).wait();
     }, p)).wait();
 
-    QVERIFY(target != 0);
+    QVERIFY(target != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(source, (size_t)QThread::currentThread());
+    QCOMPARE(source, QThread::currentThread());
     QCOMPARE(value, 42);
 }
 
 void tst_thread::then_void()
 {
-    size_t source;
+    QThread* source = nullptr;
     QPromise<void> p([&](const QPromiseResolve<void>& resolve) {
-        source = (size_t)QThread::currentThread();
+        source = QThread::currentThread();
         resolve();
     });
 
-    size_t target;
     int value = -1;
+    QThread* target = nullptr;
     qPromise(QtConcurrent::run([&](const QPromise<void>& p) {
         p.then([&]() {
-            target = (size_t)QThread::currentThread();
+            target = QThread::currentThread();
             value = 43;
         }).wait();
     }, p)).wait();
 
-    QVERIFY(target != 0);
+    QVERIFY(target != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(source, (size_t)QThread::currentThread());
+    QCOMPARE(source, QThread::currentThread());
     QCOMPARE(value, 43);
 }
 
 void tst_thread::fail()
 {
-    size_t source;
+    QThread* source = nullptr;
     QPromise<int> p([&](const QPromiseResolve<int>&, const QPromiseReject<int>& reject) {
-        source = (size_t)QThread::currentThread();
+        source = QThread::currentThread();
         reject(QString("foo"));
     });
 
-    size_t target;
     QString error;
+    QThread* target = nullptr;
     qPromise(QtConcurrent::run([&](const QPromise<int>& p) {
         p.fail([&](const QString& err) {
-            target = (size_t)QThread::currentThread();
+            target = QThread::currentThread();
             error = err;
             return -1;
         }).wait();
     }, p)).wait();
 
-    QVERIFY(target != 0);
+    QVERIFY(target != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(source, (size_t)QThread::currentThread());
+    QCOMPARE(source, QThread::currentThread());
     QCOMPARE(error, QString("foo"));
 }
 
 void tst_thread::finally()
 {
-    size_t source;
+    QThread* source = nullptr;
     QPromise<int> p([&](const QPromiseResolve<int>& resolve) {
-        source = (size_t)QThread::currentThread();
+        source = QThread::currentThread();
         resolve(42);
     });
 
-    size_t target;
     int value = -1;
+    QThread* target = nullptr;
     qPromise(QtConcurrent::run([&](const QPromise<int>& p) {
         p.finally([&]() {
-            target = (size_t)QThread::currentThread();
+            target = QThread::currentThread();
             value = 43;
         }).wait();
     }, p)).wait();
 
-    QVERIFY(target != 0);
+    QVERIFY(target != nullptr);
     QVERIFY(source != target);
-    QCOMPARE(source, (size_t)QThread::currentThread());
+    QCOMPARE(source, QThread::currentThread());
     QCOMPARE(value, 43);
 }