o3tl: Drop unused lazy_update.hxx

This was only used in the simplecanvas library
that was dropped in

    Change-Id: I301b3a42dfb6eacf6a9ef3a4851ed1d38f16ec66
    Author: Michael Weghorn <m.weghorn@posteo.de>
    Date:   Thu Jul 30 15:31:11 2026 +0200

        canvas: Drop unused simplecanvas library/component

Change-Id: I576c8e954d5ada273f49e9eba45dd71e65d49310
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/208854
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

include/o3tl/lazy_update.hxx

@@ -1,89 +0,0 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
-/*
- * This file is part of the LibreOffice project.
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
- *
- * This file incorporates work covered by the following license notice:
- *
- *   Licensed to the Apache Software Foundation (ASF) under one or more
- *   contributor license agreements. See the NOTICE file distributed
- *   with this work for additional information regarding copyright
- *   ownership. The ASF licenses this file to you under the Apache
- *   License, Version 2.0 (the "License"); you may not use this file
- *   except in compliance with the License. You may obtain a copy of
- *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
- */
-
-#ifndef INCLUDED_O3TL_LAZY_UPDATE_HXX
-#define INCLUDED_O3TL_LAZY_UPDATE_HXX
-
-#include <utility>
-
-namespace o3tl
-{
-    /** Update output object lazily
-
-        This template collects data in input type, and updates the
-        output type with the given update functor, but only if the
-        output is requested. Useful if updating is expensive, or input
-        changes frequently, but output is only comparatively seldom
-        used.
-
-        @example
-        <pre>
-LazyUpdate<InType,OutType,decltype(F)> myValue(F);
-*myValue = newInput;
-myValue->updateInput( this, that, those );
-
-output( *myValue );
-        </pre>
-        or
-        <pre>
-output( myValue.getOutValue() );
-        </pre>
-        if the compiler does not recognize the const context.
-     */
-    template<typename In, typename Out, typename Func> class LazyUpdate {
-    public:
-        LazyUpdate(Func func): func_(std::move(func)), input_(), dirty_(true) {}
-
-        In const & getInValue() const { return input_; }
-
-        Out const & getOutValue() const { return update(); }
-
-        In & operator *() {
-            dirty_ = true;
-            return input_;
-        }
-
-        In * operator ->() {
-            dirty_ = true;
-            return &input_;
-        }
-
-        Out const & operator *() const { return update();  }
-
-        Out const * operator ->() const { return &update(); }
-
-    private:
-        Out const & update() const {
-            if (dirty_) {
-                output_ = func_(input_);
-                dirty_ = false;
-            }
-            return output_;
-        }
-
-        Func const func_;
-        In input_;
-        mutable Out output_;
-        mutable bool dirty_;
-    };
-}
-
-#endif
-
-/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

o3tl/README.md

@@ -17,12 +17,6 @@ to boost, but isn't as of now)."
 
     A copy-on-write wrapper.
 
-- `[git:include/o3tl/lazy_update.hxx]`
-
-    This template collects data in input type, and updates the output type with the given update functor,
-    but only if the output is requested. Useful if updating is expensive, or input changes frequently, but
-    output is only comparatively seldom used.
-
 - `[git:include/o3tl/vector_pool.hxx]`
 
     Simple vector-based memory pool allocator.

solenv/clang-format/excludelist

@@ -5066,7 +5066,6 @@ include/o3tl/cow_wrapper.hxx
 include/o3tl/enumarray.hxx
 include/o3tl/enumrange.hxx
 include/o3tl/functional.hxx
-include/o3tl/lazy_update.hxx
 include/o3tl/numeric.hxx
 include/o3tl/safeint.hxx
 include/o3tl/sorted_vector.hxx