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/*
* Copyright 2003-2017 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 "config.h" /* must be first for large file support */
#include "Remove.hxx"
#include "UpdateDomain.hxx"
#include "db/DatabaseListener.hxx"
#include "Log.hxx"
/**
* Safely remove songs from the database. This must be done in the
* main task, because some (thread-unsafe) data structures are
* available only there.
*/
void
UpdateRemoveService::RunDeferred()
{
/* copy the list and unlock the mutex before invoking
callbacks */
std::forward_list<std::string> copy;
{
const std::lock_guard<Mutex> protect(mutex);
std::swap(uris, copy);
}
for (const auto &uri : copy) {
FormatDefault(update_domain, "removing %s", uri.c_str());
listener.OnDatabaseSongRemoved(uri.c_str());
}
/* note: if Remove() was called in the meantime, it saw an
empty list, and scheduled another event */
}
void
UpdateRemoveService::Remove(std::string &&uri)
{
bool was_empty;
{
const std::lock_guard<Mutex> protect(mutex);
was_empty = uris.empty();
uris.emplace_front(std::move(uri));
}
/* inject an event into the main thread, but only if the list
was empty; if it was not, then that even was already
pending */
if (was_empty)
DeferredMonitor::Schedule();
}