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authorMax Kellermann <max@duempel.org>2014-03-15 16:42:15 +0100
committerMax Kellermann <max@duempel.org>2014-03-16 10:26:40 +0100
commit88a0a48b030254e843e2d64651969ecfebc02540 (patch)
tree4c276d590a18d18088322aae9da9ca2d5f76c0d6 /src
parentd51b90a880260f5f7942057f5f46367007944e4c (diff)
downloadmpd-88a0a48b030254e843e2d64651969ecfebc02540.tar.gz
mpd-88a0a48b030254e843e2d64651969ecfebc02540.tar.xz
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input/BufferedInputStream: new wrapper for moving plugin to thread
Diffstat (limited to '')
-rw-r--r--src/input/ThreadInputStream.cxx204
-rw-r--r--src/input/ThreadInputStream.hxx181
2 files changed, 385 insertions, 0 deletions
diff --git a/src/input/ThreadInputStream.cxx b/src/input/ThreadInputStream.cxx
new file mode 100644
index 000000000..5271171ef
--- /dev/null
+++ b/src/input/ThreadInputStream.cxx
@@ -0,0 +1,204 @@
+/*
+ * 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.
+ */
+
+#include "config.h"
+#include "ThreadInputStream.hxx"
+#include "InputPlugin.hxx"
+#include "thread/Name.hxx"
+#include "util/CircularBuffer.hxx"
+#include "util/HugeAllocator.hxx"
+
+#include <assert.h>
+#include <string.h>
+
+ThreadInputStream::~ThreadInputStream()
+{
+ if (buffer != nullptr) {
+ buffer->Clear();
+ HugeFree(buffer->Write().data, buffer_size);
+ delete buffer;
+ }
+}
+
+InputStream *
+ThreadInputStream::Start(Error &error)
+{
+ assert(buffer == nullptr);
+
+ void *p = HugeAllocate(buffer_size);
+ if (p == nullptr) {
+ error.SetErrno();
+ return nullptr;
+ }
+
+ buffer = new CircularBuffer<uint8_t>((uint8_t *)p, buffer_size);
+
+ if (!thread.Start(ThreadFunc, this, error))
+ return nullptr;
+
+ return &base;
+}
+
+inline void
+ThreadInputStream::ThreadFunc()
+{
+ FormatThreadName("input:%s", base.plugin.name);
+
+ base.mutex.lock();
+ if (!Open(postponed_error)) {
+ base.cond.broadcast();
+ base.mutex.unlock();
+ return;
+ }
+
+ /* we're ready, tell it to our client */
+ base.ready = true;
+ base.cond.broadcast();
+
+ while (!close) {
+ assert(!postponed_error.IsDefined());
+
+ auto w = buffer->Write();
+ if (w.IsEmpty()) {
+ wake_cond.wait(base.mutex);
+ } else {
+ base.mutex.unlock();
+
+ Error error;
+ size_t nbytes = Read(w.data, w.size, error);
+
+ base.mutex.lock();
+ base.cond.broadcast();
+
+ if (nbytes == 0) {
+ eof = true;
+ postponed_error = std::move(error);
+ break;
+ }
+
+ buffer->Append(nbytes);
+ }
+ }
+
+ base.mutex.unlock();
+
+ Close();
+}
+
+void
+ThreadInputStream::ThreadFunc(void *ctx)
+{
+ ThreadInputStream &tis = *(ThreadInputStream *)ctx;
+ tis.ThreadFunc();
+}
+
+inline bool
+ThreadInputStream::Check2(Error &error)
+{
+ if (postponed_error.IsDefined()) {
+ error = std::move(postponed_error);
+ return false;
+ }
+
+ return true;
+}
+
+bool
+ThreadInputStream::Check(InputStream *is, Error &error)
+{
+ return Cast(is)->Check2(error);
+}
+
+inline bool
+ThreadInputStream::Available2()
+{
+ return !buffer->IsEmpty() || eof || postponed_error.IsDefined();
+}
+
+bool
+ThreadInputStream::Available(InputStream *is)
+{
+ return Cast(is)->Available2();
+}
+
+inline size_t
+ThreadInputStream::Read2(void *ptr, size_t size, Error &error)
+{
+ while (true) {
+ if (postponed_error.IsDefined()) {
+ error = std::move(postponed_error);
+ return 0;
+ }
+
+ auto r = buffer->Read();
+ if (!r.IsEmpty()) {
+ size_t nbytes = std::min(size, r.size);
+ memcpy(ptr, r.data, nbytes);
+ buffer->Consume(nbytes);
+ wake_cond.broadcast();
+ base.offset += nbytes;
+ return nbytes;
+ }
+
+ if (eof)
+ return 0;
+
+ base.cond.wait(base.mutex);
+ }
+}
+
+size_t
+ThreadInputStream::Read(InputStream *is, void *ptr, size_t size,
+ Error &error)
+{
+ return Cast(is)->Read2(ptr, size, error);
+}
+
+inline void
+ThreadInputStream::Close2()
+{
+ base.mutex.lock();
+ close = true;
+ wake_cond.signal();
+ base.mutex.unlock();
+
+ Cancel();
+
+ thread.Join();
+
+ delete this;
+}
+
+void
+ThreadInputStream::Close(InputStream *is)
+{
+ Cast(is)->Close2();
+}
+
+inline bool
+ThreadInputStream::IsEOF2()
+{
+ return eof;
+}
+
+bool
+ThreadInputStream::IsEOF(InputStream *is)
+{
+ return Cast(is)->IsEOF2();
+}
diff --git a/src/input/ThreadInputStream.hxx b/src/input/ThreadInputStream.hxx
new file mode 100644
index 000000000..01428d717
--- /dev/null
+++ b/src/input/ThreadInputStream.hxx
@@ -0,0 +1,181 @@
+/*
+ * 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/Cast.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 {
+ InputStream base;
+
+ 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 InputPlugin &_plugin,
+ const char *_uri, Mutex &_mutex, Cond &_cond,
+ size_t _buffer_size)
+ :base(_plugin, _uri, _mutex, _cond),
+ 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);
+
+protected:
+ void Lock() {
+ base.mutex.lock();
+ }
+
+ void Unlock() {
+ base.mutex.unlock();
+ }
+
+ const char *GetURI() const {
+ assert(thread.IsInside());
+
+ return base.uri.c_str();
+ }
+
+ void SetMimeType(const char *mime) {
+ assert(thread.IsInside());
+
+ base.mime = 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 Read(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:
+
+#if GCC_CHECK_VERSION(4,6) || defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Winvalid-offsetof"
+#endif
+
+ static constexpr ThreadInputStream *Cast(InputStream *is) {
+ return ContainerCast(is, ThreadInputStream, base);
+ }
+
+#if GCC_CHECK_VERSION(4,6) || defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
+
+ void ThreadFunc();
+ static void ThreadFunc(void *ctx);
+
+ bool Check2(Error &error);
+ bool Available2();
+ size_t Read2(void *ptr, size_t size, Error &error);
+ void Close2();
+ bool IsEOF2();
+
+public:
+ /* InputPlugin callbacks */
+ static bool Check(InputStream *is, Error &error);
+ static bool Available(InputStream *is);
+ static size_t Read(InputStream *is, void *ptr, size_t size,
+ Error &error);
+ static void Close(InputStream *is);
+ static bool IsEOF(InputStream *is);
+};
+
+#endif