flac encoder: enable Ogg FLAC and Ogg chaining

refactors GenerateOggSerial into a generic GenerateSerial
utility, under the util lib.

libFLAC may be encoded without Ogg support. If Ogg support is disabled,
libFLAC will still export Ogg-related methods (like setting a serial
number), and throw a runtime error when initializing an Ogg stream.

GenerateOggSerial does not depend on libogg. Refactoring it into
a generic GenerateSerial prevents having to add build-time checks
for libogg within the FLAC encoder plugin.

3 files changed, 0 insertions, 76 deletions

diff --git a/src/lib/xiph/OggSerial.cxx b/src/lib/xiph/OggSerial.cxx
deleted file mode 100644
index 6f5ba3f84..000000000
--- a/src/lib/xiph/OggSerial.cxx
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright 2003-2021 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 "OggSerial.hxx"
-#include "util/Compiler.h"
-
-#include <atomic>
-#include <chrono>
-
-static std::atomic_uint next_ogg_serial;
-
-int
-GenerateOggSerial() noexcept
-{
-	unsigned serial = ++next_ogg_serial;
-	if (gcc_unlikely(serial < 16)) {
-		/* first-time initialization: seed with a clock value,
-		   which is random enough for our use */
-
-		/* this code is not race-free, but good enough */
-		using namespace std::chrono;
-		const auto now = steady_clock::now().time_since_epoch();
-		const auto now_ms = duration_cast<milliseconds>(now);
-		const unsigned seed = now_ms.count();
-		next_ogg_serial = serial = seed;
-	}
-
-	return serial;
-}
-
diff --git a/src/lib/xiph/OggSerial.hxx b/src/lib/xiph/OggSerial.hxx
deleted file mode 100644
index bc6298139..000000000
--- a/src/lib/xiph/OggSerial.hxx
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Copyright 2003-2021 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.
- */
-
-#ifndef MPD_OGG_SERIAL_HXX
-#define MPD_OGG_SERIAL_HXX
-
-/**
- * Generate the next pseudo-random Ogg serial.
- */
-int
-GenerateOggSerial() noexcept;
-
-#endif
diff --git a/src/lib/xiph/meson.build b/src/lib/xiph/meson.build
index d57d68d8f..4666d28fc 100644
--- a/src/lib/xiph/meson.build
+++ b/src/lib/xiph/meson.build
@@ -72,7 +72,6 @@ if libogg_dep.found()
   ogg = static_library(
     'ogg',
     'OggVisitor.cxx',
-    'OggSerial.cxx',
     'OggSyncState.cxx',
     'OggFind.cxx',
     'OggPacket.cxx',