event/BufferedSocket: move output buffer to FullyBufferedSocket

BufferedSocket has just an input buffer, and FullyBufferedSocket adds
the output buffer.

Makefile.am

@@ -326,6 +326,7 @@ libevent_a_SOURCES = \
 	src/event/TimeoutMonitor.hxx src/event/TimeoutMonitor.cxx \
 	src/event/SocketMonitor.cxx src/event/SocketMonitor.hxx \
 	src/event/BufferedSocket.cxx src/event/BufferedSocket.hxx \
+	src/event/FullyBufferedSocket.cxx src/event/FullyBufferedSocket.hxx \
 	src/event/MultiSocketMonitor.cxx src/event/MultiSocketMonitor.hxx \
 	src/event/Loop.hxx
 

src/ClientExpire.cxx

@@ -26,7 +26,7 @@ Client::SetExpired()
 	if (IsExpired())
 		return;
 
-	BufferedSocket::Close();
+	FullyBufferedSocket::Close();
 	TimeoutMonitor::Schedule(0);
 }
 

src/ClientInternal.hxx

@@ -24,7 +24,7 @@
 #include "Client.hxx"
 #include "ClientMessage.hxx"
 #include "CommandListBuilder.hxx"
-#include "event/BufferedSocket.hxx"
+#include "event/FullyBufferedSocket.hxx"
 #include "event/TimeoutMonitor.hxx"
 #include "command.h"
 
@@ -44,7 +44,7 @@ enum {
 
 struct Partition;
 
-class Client final : private BufferedSocket, TimeoutMonitor {
+class Client final : private FullyBufferedSocket, TimeoutMonitor {
 public:
 	Partition &partition;
 	struct playlist &playlist;
@@ -89,7 +89,7 @@ public:
 	       int fd, int uid, int num);
 
 	bool IsConnected() const {
-		return BufferedSocket::IsDefined();
+		return FullyBufferedSocket::IsDefined();
 	}
 
 	gcc_pure
@@ -99,13 +99,13 @@ public:
 
 	gcc_pure
 	bool IsExpired() const {
-		return !BufferedSocket::IsDefined();
+		return !FullyBufferedSocket::IsDefined();
 	}
 
 	void Close();
 	void SetExpired();
 
-	using BufferedSocket::Write;
+	using FullyBufferedSocket::Write;
 
 	/**
 	 * Send "idle" response to this client.

src/ClientNew.cxx

@@ -49,7 +49,7 @@ static const char GREETING[] = "OK MPD " PROTOCOL_VERSION "\n";
 
 Client::Client(EventLoop &_loop, Partition &_partition,
 	       int _fd, int _uid, int _num)
-	:BufferedSocket(_fd, _loop, 16384, client_max_output_buffer_size),
+	:FullyBufferedSocket(_fd, _loop, 16384, client_max_output_buffer_size),
 	 TimeoutMonitor(_loop),
 	 partition(_partition),
 	 playlist(partition.playlist), player_control(&partition.pc),

src/event/BufferedSocket.cxx

@@ -32,26 +32,6 @@ BufferedSocket::~BufferedSocket()
 		fifo_buffer_free(input);
 }
 
-BufferedSocket::ssize_t
-BufferedSocket::DirectWrite(const void *data, size_t length)
-{
-	const auto nbytes = SocketMonitor::Write((const char *)data, length);
-	if (gcc_unlikely(nbytes < 0)) {
-		const auto code = GetSocketError();
-		if (IsSocketErrorAgain(code))
-			return 0;
-
-		Cancel();
-
-		if (IsSocketErrorClosed(code))
-			OnSocketClosed();
-		else
-			OnSocketError(NewSocketError(code));
-	}
-
-	return nbytes;
-}
-
 BufferedSocket::ssize_t
 BufferedSocket::DirectRead(void *data, size_t length)
 {
@@ -75,30 +55,6 @@ BufferedSocket::DirectRead(void *data, size_t length)
 	return -1;
 }
 
-bool
-BufferedSocket::WriteFromBuffer()
-{
-	assert(IsDefined());
-
-	size_t length;
-	const void *data = output.Read(&length);
-	if (data == nullptr) {
-		CancelWrite();
-		return true;
-	}
-
-	auto nbytes = DirectWrite(data, length);
-	if (gcc_unlikely(nbytes <= 0))
-		return nbytes == 0;
-
-	output.Consume(nbytes);
-
-	if (output.IsEmpty())
-		CancelWrite();
-
-	return true;
-}
-
 bool
 BufferedSocket::ReadToBuffer()
 {
@@ -118,38 +74,6 @@ BufferedSocket::ReadToBuffer()
 	return nbytes >= 0;
 }
 
-bool
-BufferedSocket::Write(const void *data, size_t length)
-{
-	assert(IsDefined());
-
-#if 0
-	/* TODO: disabled because this would add overhead on some callers (the ones that often), but it may be useful */
-
-	if (output.IsEmpty()) {
-		/* try to write it directly first */
-		const auto nbytes = DirectWrite(data, length);
-		if (gcc_likely(nbytes > 0)) {
-			data = (const uint8_t *)data + nbytes;
-			length -= nbytes;
-			if (length == 0)
-				return true;
-		} else if (nbytes < 0)
-			return false;
-	}
-#endif
-
-	if (!output.Append(data, length)) {
-		// TODO
-		OnSocketError(g_error_new_literal(g_quark_from_static_string("buffered_socket"),
-						  0, "Output buffer is full"));
-		return false;
-	}
-
-	ScheduleWrite();
-	return true;
-}
-
 bool
 BufferedSocket::ResumeInput()
 {
@@ -220,20 +144,6 @@ BufferedSocket::OnSocketReady(unsigned flags)
 
 		if (input == nullptr || !fifo_buffer_is_full(input))
 			ScheduleRead();
-
-		/* just in case the OnSocketInput() method has added
-		   data to the output buffer: try to send it now
-		   instead of waiting for the next event loop
-		   iteration */
-		if (!output.IsEmpty())
-			flags |= WRITE;
-	}
-
-	if (flags & WRITE) {
-		assert(!output.IsEmpty());
-
-		if (!WriteFromBuffer())
-			return false;
 	}
 
 	return true;

src/event/BufferedSocket.hxx

@@ -22,21 +22,19 @@
 
 #include "check.h"
 #include "SocketMonitor.hxx"
-#include "util/PeakBuffer.hxx"
 #include "gcc.h"
 
 struct fifo_buffer;
-class EventLoop;
 
-class BufferedSocket : private SocketMonitor {
+/**
+ * A #SocketMonitor specialization that adds an input buffer.
+ */
+class BufferedSocket : protected SocketMonitor {
 	fifo_buffer *input;
-	PeakBuffer output;
 
 public:
-	BufferedSocket(int _fd, EventLoop &_loop,
+	BufferedSocket(int _fd, EventLoop &_loop)
-		       size_t normal_size, size_t peak_size=0)
+		:SocketMonitor(_fd, _loop), input(nullptr) {
-		:SocketMonitor(_fd, _loop), input(nullptr),
-		 output(normal_size, peak_size) {
 		ScheduleRead();
 	}
 
@@ -44,18 +42,11 @@ public:
 
 	using SocketMonitor::IsDefined;
 	using SocketMonitor::Close;
+	using SocketMonitor::Write;
 
 private:
-	ssize_t DirectWrite(const void *data, size_t length);
 	ssize_t DirectRead(void *data, size_t length);
 
-	/**
-	 * Send data from the output buffer to the socket.
-	 *
-	 * @return false if the socket has been closed
-	 */
-	bool WriteFromBuffer();
-
 	/**
 	 * Receive data from the socket to the input buffer.
 	 *
@@ -64,11 +55,6 @@ private:
 	bool ReadToBuffer();
 
 protected:
-	/**
-	 * @return false if the socket has been closed
-	 */
-	bool Write(const void *data, size_t length);
-
 	/**
 	 * @return false if the socket has been closed
 	 */
@@ -112,7 +98,6 @@ protected:
 	virtual void OnSocketError(GError *error) = 0;
 	virtual void OnSocketClosed() = 0;
 
-private:
 	virtual bool OnSocketReady(unsigned flags) override;
 };
 

src/event/FullyBufferedSocket.cxx

@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2003-2013 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 "FullyBufferedSocket.hxx"
+#include "SocketError.hxx"
+#include "util/fifo_buffer.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+
+#ifndef WIN32
+#include <sys/types.h>
+#include <sys/socket.h>
+#endif
+
+FullyBufferedSocket::ssize_t
+FullyBufferedSocket::DirectWrite(const void *data, size_t length)
+{
+	const auto nbytes = SocketMonitor::Write((const char *)data, length);
+	if (gcc_unlikely(nbytes < 0)) {
+		const auto code = GetSocketError();
+		if (IsSocketErrorAgain(code))
+			return 0;
+
+		Cancel();
+
+		if (IsSocketErrorClosed(code))
+			OnSocketClosed();
+		else
+			OnSocketError(NewSocketError(code));
+	}
+
+	return nbytes;
+}
+
+bool
+FullyBufferedSocket::WriteFromBuffer()
+{
+	assert(IsDefined());
+
+	size_t length;
+	const void *data = output.Read(&length);
+	if (data == nullptr) {
+		CancelWrite();
+		return true;
+	}
+
+	auto nbytes = DirectWrite(data, length);
+	if (gcc_unlikely(nbytes <= 0))
+		return nbytes == 0;
+
+	output.Consume(nbytes);
+
+	if (output.IsEmpty())
+		CancelWrite();
+
+	return true;
+}
+
+bool
+FullyBufferedSocket::Write(const void *data, size_t length)
+{
+	assert(IsDefined());
+
+#if 0
+	/* TODO: disabled because this would add overhead on some callers (the ones that often), but it may be useful */
+
+	if (output.IsEmpty()) {
+		/* try to write it directly first */
+		const auto nbytes = DirectWrite(data, length);
+		if (gcc_likely(nbytes > 0)) {
+			data = (const uint8_t *)data + nbytes;
+			length -= nbytes;
+			if (length == 0)
+				return true;
+		} else if (nbytes < 0)
+			return false;
+	}
+#endif
+
+	if (!output.Append(data, length)) {
+		// TODO
+		OnSocketError(g_error_new_literal(g_quark_from_static_string("buffered_socket"),
+						  0, "Output buffer is full"));
+		return false;
+	}
+
+	ScheduleWrite();
+	return true;
+}
+
+bool
+FullyBufferedSocket::OnSocketReady(unsigned flags)
+{
+	const bool was_empty = output.IsEmpty();
+	if (!BufferedSocket::OnSocketReady(flags))
+		return false;
+
+	if (was_empty && !output.IsEmpty())
+		/* just in case the OnSocketInput() method has added
+		   data to the output buffer: try to send it now
+		   instead of waiting for the next event loop
+		   iteration */
+		flags |= WRITE;
+
+	if (flags & WRITE) {
+		assert(!output.IsEmpty());
+
+		if (!WriteFromBuffer())
+			return false;
+	}
+
+	return true;
+}

src/event/FullyBufferedSocket.hxx

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2003-2013 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_FULLY_BUFFERED_SOCKET_HXX
+#define MPD_FULLY_BUFFERED_SOCKET_HXX
+
+#include "check.h"
+#include "BufferedSocket.hxx"
+#include "util/PeakBuffer.hxx"
+#include "gcc.h"
+
+/**
+ * A #BufferedSocket specialization that adds an output buffer.
+ */
+class FullyBufferedSocket : protected BufferedSocket {
+	PeakBuffer output;
+
+public:
+	FullyBufferedSocket(int _fd, EventLoop &_loop,
+			    size_t normal_size, size_t peak_size=0)
+		:BufferedSocket(_fd, _loop),
+		 output(normal_size, peak_size) {
+	}
+
+	using BufferedSocket::IsDefined;
+	using BufferedSocket::Close;
+
+private:
+	ssize_t DirectWrite(const void *data, size_t length);
+
+	/**
+	 * Send data from the output buffer to the socket.
+	 *
+	 * @return false if the socket has been closed
+	 */
+	bool WriteFromBuffer();
+
+protected:
+	/**
+	 * @return false if the socket has been closed
+	 */
+	bool Write(const void *data, size_t length);
+
+	virtual bool OnSocketReady(unsigned flags) override;
+};
+
+#endif