b14224fe97
using an idea from dtardon: <dtardon> noelgrandin, hi. could you try to run the unusedmethods clang plugin with "make build-nocheck"? that would catch functions that are only used in tests. e.g., i just removed the whole o3tl::range class, which has not been used in many years, but htere was a test for it... <noelgrandin> dtardon, interesting idea! Sure, I can do that. Change-Id: I5653953a426a2186a1e43017212d87ffce520387 Reviewed-on: https://gerrit.libreoffice.org/22041 Reviewed-by: Noel Grandin <noelgrandin@gmail.com> Tested-by: Noel Grandin <noelgrandin@gmail.com>
89 lines
2.6 KiB
C++
89 lines
2.6 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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#ifndef INCLUDED_O3TL_LAZY_UPDATE_HXX
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#define INCLUDED_O3TL_LAZY_UPDATE_HXX
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#include <utility>
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namespace o3tl
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{
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/** Update output object lazily
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This template collects data in input type, and updates the
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output type with the given update functor, but only if the
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output is requested. Useful if updating is expensive, or input
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changes frequently, but output is only comparatively seldom
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used.
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@example
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<pre>
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LazyUpdate<InType,OutType,decltype(F)> myValue(F);
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*myValue = newInput;
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myValue->updateInput( this, that, those );
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output( *myValue );
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</pre>
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or
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<pre>
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output( myValue.getOutValue() );
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</pre>
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if the compiler does not recognize the const context.
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*/
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template<typename In, typename Out, typename Func> class LazyUpdate {
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public:
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LazyUpdate(Func const & func): func_(func), input_(), dirty_(true) {}
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In const & getInValue() const { return input_; }
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Out const & getOutValue() const { return update(); }
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In & operator *() {
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dirty_ = true;
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return input_;
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}
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In * operator ->() {
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dirty_ = true;
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return &input_;
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}
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Out const & operator *() const { return update(); }
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Out const * operator ->() const { return &update(); }
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private:
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Out const & update() const {
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if (dirty_) {
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output_ = func_(input_);
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dirty_ = false;
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}
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return output_;
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}
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Func const func_;
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In input_;
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mutable Out output_;
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mutable bool dirty_;
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};
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}
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#endif
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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