input/rewind: new input_stream wrapper to allow stream rewinding

This replaces the rewinding buffer code from the CURL input plugin.
It is more generic, and allows rewinding even when the server sends
Icy-Metadata (which would have been too difficult to implement within
the CURL plugin).

This is a rather complex patch for the stable branch (v0.15.x), but it
fixes a serious problem: the "vorbis" decoder plugin was unable to
play streams with Icy-Metadata, because it couldn't rewind the stream
after detecting the codec (Vorbis vs. FLAC).

1 files changed, 49 insertions, 0 deletions

diff --git a/src/input/rewind_input_plugin.h b/src/input/rewind_input_plugin.h
new file mode 100644
index 000000000..33fedf4e1
--- /dev/null
+++ b/src/input/rewind_input_plugin.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2003-2009 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.
+ */
+
+/** \file
+ *
+ * A wrapper for an input_stream object which allows cheap buffered
+ * rewinding.  This is useful while detecting the stream codec (let
+ * each decoder plugin peek a portion from the stream).
+ */
+
+#ifndef MPD_INPUT_REWIND_H
+#define MPD_INPUT_REWIND_H
+
+#include "config.h"
+
+struct input_stream;
+
+#ifdef HAVE_CURL
+
+void
+input_rewind_open(struct input_stream *is);
+
+#else
+
+static inline void
+input_rewind_open(struct input_stream *is)
+{
+	(void)is;
+}
+
+#endif
+
+#endif