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/*
* Copyright 2003-2019 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "OptimizeFilter.hxx"
#include "AndSongFilter.hxx"
#include "NotSongFilter.hxx"
#include "TagSongFilter.hxx"
#include "UriSongFilter.hxx"
void
OptimizeSongFilter(AndSongFilter &af) noexcept
{
for (auto i = af.items.begin(); i != af.items.end();) {
auto f = OptimizeSongFilter(std::move(*i));
if (auto *nested = dynamic_cast<AndSongFilter *>(f.get())) {
/* collapse nested #AndSongFilter instances */
af.items.splice(i, std::move(nested->items));
i = af.items.erase(i);
} else {
*i = std::move(f);
++i;
}
}
}
ISongFilterPtr
OptimizeSongFilter(ISongFilterPtr f) noexcept
{
if (auto *af = dynamic_cast<AndSongFilter *>(f.get())) {
/* first optimize all items */
OptimizeSongFilter(*af);
if (!af->items.empty() &&
std::next(af->items.begin()) == af->items.end())
/* only one item: the containing
#AndSongFilter can be removed */
return std::move(af->items.front());
} else if (auto *nf = dynamic_cast<NotSongFilter *>(f.get())) {
auto child = OptimizeSongFilter(std::move(nf->child));
if (auto *tf = dynamic_cast<TagSongFilter *>(child.get())) {
/* #TagSongFilter has its own "negated" flag,
so we can drop the #NotSongFilter
container */
tf->ToggleNegated();
return child;
} else if (auto *uf = dynamic_cast<UriSongFilter *>(child.get())) {
/* same for #UriSongFilter */
uf->ToggleNegated();
return child;
}
nf->child = std::move(child);
}
return f;
}