aboutsummaryrefslogtreecommitdiffstats
path: root/src/input/ThreadInputStream.hxx
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/input/ThreadInputStream.hxx144
1 files changed, 144 insertions, 0 deletions
diff --git a/src/input/ThreadInputStream.hxx b/src/input/ThreadInputStream.hxx
new file mode 100644
index 000000000..c6ac7669c
--- /dev/null
+++ b/src/input/ThreadInputStream.hxx
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2003-2014 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_THREAD_INPUT_STREAM_HXX
+#define MPD_THREAD_INPUT_STREAM_HXX
+
+#include "check.h"
+#include "InputStream.hxx"
+#include "thread/Thread.hxx"
+#include "thread/Cond.hxx"
+#include "util/Error.hxx"
+
+#include <stdint.h>
+
+template<typename T> class CircularBuffer;
+
+/**
+ * Helper class for moving InputStream implementations with blocking
+ * backend library implementation to a dedicated thread. Data is
+ * being read into a ring buffer, and that buffer is then consumed by
+ * another thread using the regular #InputStream API. This class
+ * manages the thread and the buffer.
+ *
+ * This works only for "streams": unknown length, no seeking, no tags.
+ */
+class ThreadInputStream : public InputStream {
+ const char *const plugin;
+
+ Thread thread;
+
+ /**
+ * Signalled when the thread shall be woken up: when data from
+ * the buffer has been consumed and when the stream shall be
+ * closed.
+ */
+ Cond wake_cond;
+
+ Error postponed_error;
+
+ const size_t buffer_size;
+ CircularBuffer<uint8_t> *buffer;
+
+ /**
+ * Shall the stream be closed?
+ */
+ bool close;
+
+ /**
+ * Has the end of the stream been seen by the thread?
+ */
+ bool eof;
+
+public:
+ ThreadInputStream(const char *_plugin,
+ const char *_uri, Mutex &_mutex, Cond &_cond,
+ size_t _buffer_size)
+ :InputStream(_uri, _mutex, _cond),
+ plugin(_plugin),
+ buffer_size(_buffer_size),
+ buffer(nullptr),
+ close(false), eof(false) {}
+
+ virtual ~ThreadInputStream();
+
+ /**
+ * Initialize the object and start the thread.
+ *
+ * @return false on error
+ */
+ InputStream *Start(Error &error);
+
+ /* virtual methods from InputStream */
+ bool Check(Error &error) override final;
+ bool IsEOF() override final;
+ bool IsAvailable() override final;
+ size_t Read(void *ptr, size_t size, Error &error) override final;
+
+protected:
+ void SetMimeType(const char *_mime) {
+ assert(thread.IsInside());
+
+ InputStream::SetMimeType(_mime);
+ }
+
+ /* to be implemented by the plugin */
+
+ /**
+ * Optional initialization after entering the thread. After
+ * this returns with success, the InputStream::ready flag is
+ * set.
+ *
+ * The #InputStream is locked. Unlock/relock it if you do a
+ * blocking operation.
+ */
+ virtual bool Open(gcc_unused Error &error) {
+ return true;
+ }
+
+ /**
+ * Read from the stream.
+ *
+ * The #InputStream is not locked.
+ *
+ * @return 0 on end-of-file or on error
+ */
+ virtual size_t ThreadRead(void *ptr, size_t size, Error &error) = 0;
+
+ /**
+ * Optional deinitialization before leaving the thread.
+ *
+ * The #InputStream is not locked.
+ */
+ virtual void Close() {}
+
+ /**
+ * Called from the client thread to cancel a Read() inside the
+ * thread.
+ *
+ * The #InputStream is not locked.
+ */
+ virtual void Cancel() {}
+
+private:
+ void ThreadFunc();
+ static void ThreadFunc(void *ctx);
+};
+
+#endif