input/BufferedInputStream: new wrapper for moving plugin to thread

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();
+}