Added WorkManager to manage background tasks.

Relies heavily on the QThreadPool.

core/WorkManager.cpp

@@ -0,0 +1,47 @@
+#include "WorkManager.h"
+
+#include <QRunnable.h>
+#include <QThreadPool.h>
+#include <deque>
+#include <functional>
+#include <mutex>
+
+
+class WorkManagerImpl: public WorkManager {
+public:
+	virtual void addRunnable(QRunnable *runnable) override;
+	virtual void addWork(Work work) override;
+};
+
+
+
+std::shared_ptr<WorkManager> WorkManager::getWorkManager()
+{
+	static std::shared_ptr<WorkManager> wm = std::make_shared<WorkManagerImpl>();
+	return wm;
+}
+
+void WorkManagerImpl::addRunnable(QRunnable *runnable)
+{
+	auto tp = QThreadPool::globalInstance();
+	tp->start(runnable);
+}
+
+class CallableTask : public QRunnable {
+public:
+	CallableTask(WorkManager::Work &&w)
+		: work(std::move(w))
+	{}
+protected:
+	void run()
+	{
+		work();
+	}
+private:
+	WorkManager::Work work;
+};
+
+void WorkManagerImpl::addWork(Work work)
+{
+	addRunnable(new CallableTask(std::move(work)));
+}

core/WorkManager.h

@@ -0,0 +1,20 @@
+#ifndef WORKMANAGER_H
+#define WORKMANAGER_H
+
+#include <functional>
+#include <memory>
+
+class QRunnable;
+
+class WorkManager {
+public:
+
+	static std::shared_ptr<WorkManager> getWorkManager();
+
+	using Work = std::function<void()>;
+	virtual void addRunnable(QRunnable *runnable) = 0;
+	virtual void addWork(Work work) = 0;
+
+};
+
+#endif // WORKMANAGER_H

core/core.pro

@@ -38,7 +38,8 @@ SOURCES += my_boost_assert_handler.cpp \
     BackupFormatModel.cpp \
 	QueuedBackgroundTask.cpp \
     ExplainTreeModelItem.cpp \
-    jsoncpp.cpp
+    jsoncpp.cpp \
+    WorkManager.cpp
 
 HEADERS += PasswordManager.h \
     SqlLexer.h \
@@ -48,7 +49,8 @@ HEADERS += PasswordManager.h \
 	QueuedBackgroundTask.h \
 	Expected.h \
     ExplainTreeModelItem.h \
-    json/json.h
+    json/json.h \
+    WorkManager.h
 	
 unix {
     target.path = /usr/lib