4e0e4c00bf
SonarLint reports the latter to be better:
std::scoped_lock basically provides the same feature as std::lock_guard,
but is more generic: It can lock several mutexes at the same time, with a
deadlock prevention mechanism (see {rule:cpp:S5524}). The equivalent code
to perform simultaneous locking with std::lock_guard is significantly more
complex. Therefore, it is simpler to use std::scoped_lock all the time,
even when locking only one mutex (there will be no performance impact).
Signed-off-by: Rosen Penev <rosenp@gmail.com>
90 lines
2.3 KiB
C++
90 lines
2.3 KiB
C++
/*
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* Copyright 2003-2021 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "ClientInit.hxx"
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#include "Init.hxx"
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#include "Callback.hxx"
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#include "thread/Mutex.hxx"
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#include "util/RuntimeError.hxx"
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#include <upnptools.h>
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#include <cassert>
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static Mutex upnp_client_init_mutex;
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static unsigned upnp_client_ref;
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static UpnpClient_Handle upnp_client_handle;
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static int
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UpnpClientCallback(Upnp_EventType et,
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const void *evp,
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void *cookie) noexcept
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{
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if (cookie == nullptr)
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/* this is the cookie passed to UpnpRegisterClient();
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but can this ever happen? Will libupnp ever invoke
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the registered callback without that cookie? */
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return UPNP_E_SUCCESS;
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UpnpCallback &callback = UpnpCallback::FromUpnpCookie(cookie);
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return callback.Invoke(et, evp);
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}
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static void
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DoInit()
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{
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auto code = UpnpRegisterClient(UpnpClientCallback, nullptr,
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&upnp_client_handle);
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if (code != UPNP_E_SUCCESS)
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throw FormatRuntimeError("UpnpRegisterClient() failed: %s",
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UpnpGetErrorMessage(code));
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}
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UpnpClient_Handle
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UpnpClientGlobalInit(const char* iface)
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{
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UpnpGlobalInit(iface);
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try {
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const std::scoped_lock<Mutex> protect(upnp_client_init_mutex);
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if (upnp_client_ref == 0)
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DoInit();
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} catch (...) {
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UpnpGlobalFinish();
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throw;
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}
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++upnp_client_ref;
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return upnp_client_handle;
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}
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void
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UpnpClientGlobalFinish() noexcept
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{
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{
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const std::scoped_lock<Mutex> protect(upnp_client_init_mutex);
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assert(upnp_client_ref > 0);
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if (--upnp_client_ref == 0)
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UpnpUnRegisterClient(upnp_client_handle);
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}
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UpnpGlobalFinish();
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}
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