Initial commit.

ext/libstrawberry-common/core/closure.h

@@ -0,0 +1,248 @@
+/* This file is part of Strawberry.
+   Copyright 2011, David Sansome <me@davidsansome.com>
+
+   Strawberry is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   Strawberry is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef CLOSURE_H
+#define CLOSURE_H
+
+#include <chrono>
+#include <functional>
+#include <memory>
+
+#include <QFuture>
+#include <QFutureWatcher>
+#include <QMetaMethod>
+#include <QObject>
+#include <QSharedPointer>
+#include <QTimer>
+
+namespace _detail {
+
+class ObjectHelper;
+
+// Interface for ObjectHelper to call on signal emission.
+class ClosureBase {
+ public:
+  virtual ~ClosureBase();
+  virtual void Invoke() = 0;
+
+  // Tests only.
+  ObjectHelper* helper() const;
+
+ protected:
+  explicit ClosureBase(ObjectHelper*);
+  ObjectHelper* helper_;
+
+ private:
+  Q_DISABLE_COPY(ClosureBase);
+};
+
+// QObject helper as templated QObjects do not work.
+// Connects to the given signal and invokes the closure when called.
+// Deletes itself and the Closure after being invoked.
+class ObjectHelper : public QObject {
+  Q_OBJECT
+ public:
+  ObjectHelper(QObject* parent, const char* signal, ClosureBase* closure);
+
+ private slots:
+  void Invoked();
+
+ private:
+  std::unique_ptr<ClosureBase> closure_;
+  Q_DISABLE_COPY(ObjectHelper);
+};
+
+// Helpers for unpacking a variadic template list.
+
+// Base case of no arguments.
+void Unpack(QList<QGenericArgument>*);
+
+template <typename Arg>
+void Unpack(QList<QGenericArgument>* list, const Arg& arg) {
+  list->append(Q_ARG(Arg, arg));
+}
+
+template <typename Head, typename... Tail>
+void Unpack(QList<QGenericArgument>* list, const Head& head, const Tail&... tail) {
+  Unpack(list, head);
+  Unpack(list, tail...);
+}
+
+template <typename... Args>
+class Closure : public ClosureBase {
+ public:
+  Closure(
+      QObject* sender,
+      const char* signal,
+      QObject* receiver,
+      const char* slot,
+      const Args&... args)
+      : ClosureBase(new ObjectHelper(sender, signal, this)),
+        // std::bind is the easiest way to store an argument list.
+        function_(std::bind(&Closure<Args...>::Call, this, args...)),
+        receiver_(receiver) {
+    const QMetaObject* meta_receiver = receiver->metaObject();
+    QByteArray normalised_slot = QMetaObject::normalizedSignature(slot + 1);
+    const int index = meta_receiver->indexOfSlot(normalised_slot.constData());
+    Q_ASSERT(index != -1);
+    slot_ = meta_receiver->method(index);
+    QObject::connect(receiver_, SIGNAL(destroyed()), helper_, SLOT(deleteLater()));
+  }
+
+  virtual void Invoke() {
+    function_();
+  }
+
+ private:
+  void Call(const Args&... args) {
+    QList<QGenericArgument> arg_list;
+    Unpack(&arg_list, args...);
+
+    slot_.invoke(
+        receiver_,
+                 arg_list.size() > 0 ? arg_list[0] : QGenericArgument(),
+                 arg_list.size() > 1 ? arg_list[1] : QGenericArgument(),
+                 arg_list.size() > 2 ? arg_list[2] : QGenericArgument(),
+                 arg_list.size() > 3 ? arg_list[3] : QGenericArgument(),
+                 arg_list.size() > 4 ? arg_list[4] : QGenericArgument(),
+                 arg_list.size() > 5 ? arg_list[5] : QGenericArgument(),
+                 arg_list.size() > 6 ? arg_list[6] : QGenericArgument(),
+                 arg_list.size() > 7 ? arg_list[7] : QGenericArgument(),
+                 arg_list.size() > 8 ? arg_list[8] : QGenericArgument(),
+                 arg_list.size() > 9 ? arg_list[9] : QGenericArgument());
+  }
+
+  std::function<void()> function_;
+  QObject* receiver_;
+  QMetaMethod slot_;
+};
+
+template <typename T, typename... Args>
+class SharedClosure : public Closure<Args...> {
+ public:
+  SharedClosure(
+      QSharedPointer<T> sender,
+      const char* signal,
+      QObject* receiver,
+      const char* slot,
+      const Args&... args)
+    : Closure<Args...>(
+        sender.data(),
+        signal,
+        receiver,
+        slot,
+        args...),
+      data_(sender) {
+  }
+
+ private:
+  QSharedPointer<T> data_;
+};
+
+class CallbackClosure : public ClosureBase {
+ public:
+  CallbackClosure(QObject* sender, const char* signal,
+                  std::function<void()> callback);
+
+  virtual void Invoke();
+
+ private:
+  std::function<void()> callback_;
+};
+
+}  // namespace _detail
+
+template <typename... Args>
+_detail::ClosureBase* NewClosure(
+    QObject* sender,
+    const char* signal,
+    QObject* receiver,
+    const char* slot,
+                                 const Args&... args) {
+  return new _detail::Closure<Args...>(
+      sender, signal, receiver, slot, args...);
+}
+
+// QSharedPointer variant
+template <typename T, typename... Args>
+_detail::ClosureBase* NewClosure(
+    QSharedPointer<T> sender,
+    const char* signal,
+    QObject* receiver,
+    const char* slot,
+                                 const Args&... args) {
+  return new _detail::SharedClosure<T, Args...>(
+      sender, signal, receiver, slot, args...);
+}
+
+_detail::ClosureBase* NewClosure(QObject* sender, const char* signal, std::function<void()> callback);
+
+template <typename... Args>
+_detail::ClosureBase* NewClosure(QObject* sender, const char* signal, std::function<void(Args...)> callback, const Args&... args) {
+  return NewClosure(sender, signal, std::bind(callback, args...));
+}
+
+template <typename... Args>
+_detail::ClosureBase* NewClosure(
+    QObject* sender,
+    const char* signal,
+                                 void (*callback)(Args...),
+                                 const Args&... args) {
+  return NewClosure(sender, signal, std::bind(callback, args...));
+}
+
+template <typename T, typename Unused, typename... Args>
+_detail::ClosureBase* NewClosure(
+    QObject* sender,
+    const char* signal,
+                                 T* receiver, Unused (T::*callback)(Args...),
+                                 const Args&... args) {
+  return NewClosure(sender, signal, std::bind(callback, receiver, args...));
+}
+
+template <typename T, typename... Args>
+_detail::ClosureBase* NewClosure(QFuture<T> future, QObject* receiver, const char* slot, const Args&... args) {
+  QFutureWatcher<T>* watcher = new QFutureWatcher<T>;
+  watcher->setFuture(future);
+  QObject::connect(watcher, SIGNAL(finished()), watcher, SLOT(deleteLater()));
+  return NewClosure(watcher, SIGNAL(finished()), receiver, slot, args...);
+}
+
+template <typename T, typename F, typename... Args>
+_detail::ClosureBase* NewClosure(QFuture<T> future, const F& callback, const Args&... args) {
+  QFutureWatcher<T>* watcher = new QFutureWatcher<T>;
+  watcher->setFuture(future);
+  QObject::connect(watcher, SIGNAL(finished()), watcher, SLOT(deleteLater()));
+  return NewClosure(watcher, SIGNAL(finished()), callback, args...);
+}
+
+void DoAfter(QObject* receiver, const char* slot, int msec);
+void DoAfter(std::function<void()> callback, std::chrono::milliseconds msec);
+void DoInAMinuteOrSo(QObject* receiver, const char* slot);
+
+template <typename R, typename P>
+void DoAfter(std::function<void()> callback, std::chrono::duration<R, P> duration) {
+  QTimer* timer = new QTimer;
+  timer->setSingleShot(true);
+  NewClosure(timer, SIGNAL(timeout()), callback);
+  QObject::connect(timer, SIGNAL(timeout()), timer, SLOT(deleteLater()));
+  std::chrono::milliseconds msec = std::chrono::duration_cast<std::chrono::milliseconds>(duration);
+  timer->start(msec.count());
+}
+
+#endif  // CLOSURE_H
+