threadex.hxx

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#ifndef INCLUDED_VCL_THREADEX_HXX
#define INCLUDED_VCL_THREADEX_HXX
 
#include <osl/conditn.hxx>
#include <tools/link.hxx>
#include <vcl/dllapi.h>
 
#include <optional>
#include <memory>
#include <utility>
 
namespace vcl
{
    class VCL_DLLPUBLIC SolarThreadExecutor
    {
        osl::Condition          m_aStart;
        osl::Condition          m_aFinish;
        bool                    m_bTimeout;
 
        DECL_DLLPRIVATE_LINK( worker, void*, void );
 
    public:
        SolarThreadExecutor();
        virtual ~SolarThreadExecutor();
 
        virtual void doIt() = 0;
        void execute();
    };
 
namespace solarthread {
 
namespace detail {
 
template <typename FuncT, typename ResultT>
class GenericSolarThreadExecutor final : public SolarThreadExecutor
{
public:
    static ResultT exec( FuncT const& func )
    {
        typedef GenericSolarThreadExecutor<FuncT, ResultT> ExecutorT;
        ::std::unique_ptr<ExecutorT> const pExecutor( new ExecutorT(func) );
        pExecutor->execute();
        if (pExecutor->m_exc)
            std::rethrow_exception(pExecutor->m_exc);
        return *pExecutor->m_result;
    }
 
private:
    explicit GenericSolarThreadExecutor( FuncT func )
        : m_func(std::move(func)), m_result() {}
 
    virtual void doIt() override
    {
        try {
            m_result = m_func();
        }
        catch (...) {
            m_exc = std::current_exception();
        }
    }
 
    std::exception_ptr m_exc;
#ifdef _MSC_VER
    FuncT m_func; // "const" and std::bind() results in Error C3848 expression would lose const-volatile qualifiers
#else
    FuncT const m_func;
#endif
    // using std::optional here omits the need that ResultT is default
    // constructable:
    ::std::optional<ResultT> m_result;
};
 
template <typename FuncT>
class GenericSolarThreadExecutor<FuncT, void> final : public SolarThreadExecutor
{
public:
    static void exec( FuncT const& func )
    {
        typedef GenericSolarThreadExecutor<FuncT, void> ExecutorT;
        ::std::unique_ptr<ExecutorT> const pExecutor( new ExecutorT(func) );
        pExecutor->execute();
        if (pExecutor->m_exc)
            std::rethrow_exception(pExecutor->m_exc);
    }
 
private:
    explicit GenericSolarThreadExecutor( FuncT func )
        : m_func(std::move(func)) {}
 
    virtual void doIt() override
    {
        try {
            m_func();
        }
        catch (...) {
            m_exc = std::current_exception();
        }
    }
 
    std::exception_ptr m_exc;
    FuncT const m_func;
};
 
} // namespace detail
 
 
template <typename FuncT>
inline auto syncExecute(FuncT const& func) -> decltype(func())
{
    return detail::GenericSolarThreadExecutor<
        FuncT, decltype(func())>::exec(func);
}
 
} // namespace solarthread
} // namespace vcl
 
#endif // INCLUDED_VCL_THREADEX_HXX
 
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