include/vcl/threadex.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_VCL_THREADEX_HXX
  21 #define INCLUDED_VCL_THREADEX_HXX
  22
  23 #include <osl/conditn.hxx>
  24 #include <osl/thread.h>
  25 #include <tools/link.hxx>
  26 #include <vcl/dllapi.h>
  27
  28 #include <cppuhelper/exc_hlp.hxx>
  29 #include <boost/optional.hpp>
  30 #include <memory>
  31
  32 namespace vcl
  33 {
  34     class VCL_DLLPUBLIC SolarThreadExecutor
  35     {
  36         osl::Condition          m_aStart;
  37         osl::Condition          m_aFinish;
  38         long                    m_nReturn;
  39         bool                    m_bTimeout;
  40
  41         DECL_DLLPRIVATE_LINK( worker, void*, void );
  42
  43     public:
  44         SolarThreadExecutor();
  45         virtual ~SolarThreadExecutor();
  46
  47         virtual long doIt() = 0;
  48         void execute();
  49     };
  50
  51 namespace solarthread {
  52
  53 /// @internal
  54 namespace detail {
  55
  56 template <typename FuncT, typename ResultT>
  57 class GenericSolarThreadExecutor : public SolarThreadExecutor
  58 {
  59 public:
  60     static ResultT exec( FuncT const& func )
  61     {
  62         typedef GenericSolarThreadExecutor<FuncT, ResultT> ExecutorT;
  63         ::std::unique_ptr<ExecutorT> const pExecutor( new ExecutorT(func) );
  64         pExecutor->execute();
  65         if (pExecutor->m_exc.hasValue())
  66             ::cppu::throwException( pExecutor->m_exc );
  67         return *pExecutor->m_result;
  68     }
  69
  70 private:
  71     explicit GenericSolarThreadExecutor( FuncT const& func )
  72         : m_exc(), m_func(func), m_result() {}
  73
  74     virtual long doIt() override
  75     {
  76         try {
  77             m_result.reset( m_func() );
  78         }
  79         catch (css::uno::Exception &) {
  80             // only UNO exceptions can be dispatched:
  81             m_exc = ::cppu::getCaughtException();
  82         }
  83         return 0;
  84     }
  85
  86     css::uno::Any m_exc;
  87 #ifdef _MSC_VER
  88     FuncT m_func; // "const" and std::bind() results in Error C3848 expression would lose const-volatile qualifiers
  89 #else
  90     FuncT const m_func;
  91 #endif
  92     // using boost::optional here omits the need that ResultT is default
  93     // constructable:
  94     ::boost::optional<ResultT> m_result;
  95 };
  96
  97 template <typename FuncT>
  98 class GenericSolarThreadExecutor<FuncT, void> : public SolarThreadExecutor
  99 {
 100 private:
 101     explicit GenericSolarThreadExecutor( FuncT const& func )
 102         : m_exc(), m_func(func) {}
 103
 104     virtual long doIt() override
 105     {
 106         try {
 107             m_func();
 108         }
 109         catch (css::uno::Exception &) {
 110             // only UNO exceptions can be dispatched:
 111             m_exc = ::cppu::getCaughtException();
 112         }
 113         return 0;
 114     }
 115
 116     css::uno::Any m_exc;
 117     FuncT const m_func;
 118 };
 119
 120 } // namespace detail
 121
 122
 123 /** This function will execute the passed functor synchronously in the
 124     solar thread, thus the calling thread will (eventually) be blocked until
 125     the functor has been called.
 126     Any UNO exception that came up calling the functor in the solar thread
 127     will be caught and rethrown in the calling thread.  Any non-UNO
 128     exception needs to be handled by the called functor.
 129     The result type of this function needs to be default constructable.
 130     Please keep in mind not to pass addresses to stack variables
 131     (e.g. for out parameters) to foreign threads, use inout_by_ref()
 132     for this purpose.  For in parameters, this may not affect you, because
 133     the functor object is copy constructed into free store.  This way
 134     you must not use \verbatim std::cref()/std::ref() \endverbatim or similar
 135     for objects on your thread's stack.
 136     Use inout_by_ref() or inout_by_ptr() for this purpose, e.g.
 137
 138     \code{.cpp}
 139         using namespace vcl::solarthread;
 140
 141         long n = 3;
 142         // calling foo( long & r ):
 143         syncExecute( std::bind( &foo, inout_by_ref(n) ) );
 144         // calling foo( long * p ):
 145         syncExecute( std::bind( &foo, inout_by_ptr(&n) ) );
 146
 147         char const* pc = "default";
 148         // calling foo( char const** ppc ):
 149         syncExecute( std::bind( &foo, inout_by_ptr(&pc) ) );
 150         // calling foo( char const*& rpc ):
 151         syncExecute( std::bind( &foo, inout_by_ref(pc) ) );
 152     \endcode
 153
 154     @tpl ResultT result type, defaults to FuncT::result_type to seamlessly
 155                  support mem_fn and bind
 156     @tpl FuncT functor type, let your compiler deduce this type
 157     @param func functor object to be executed in solar thread
 158     @return return value of functor
 159 */
 160 template <typename FuncT>
 161 inline typename FuncT::result_type syncExecute( FuncT const& func )
 162 {
 163     return detail::GenericSolarThreadExecutor<
 164         FuncT, typename FuncT::result_type>::exec(func);
 165 }
 166
 167 } // namespace solarthread
 168 } // namespace vcl
 169
 170 #endif // INCLUDED_VCL_THREADEX_HXX
 171
 172 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */