various commits from SM4 SVN, courtesy of Glenn and Vyhd.

src/RageFileManager_ReadAhead.cpp

@@ -0,0 +1,174 @@
+#include "global.h"
+#include "RageFileManager_ReadAhead.h"
+#include "RageThreads.h"
+#include "RageLog.h"
+
+#include <fcntl.h>
+#include <cerrno>
+#if defined(WIN32)
+#include <io.h>
+#endif
+
+#if defined(HAVE_POSIX_FADVISE)
+void RageFileManagerReadAhead::Init() { }
+void RageFileManagerReadAhead::Shutdown() { }
+void RageFileManagerReadAhead::ReadAhead( RageFileBasic *pFile, int iBytes )
+{
+	int iFD = pFile->GetFD();
+	if( iFD == -1 )
+		return;
+
+	int iStart = lseek( iFD, 0, SEEK_CUR );
+	posix_fadvise( iFD, iStart, iBytes, POSIX_FADV_WILLNEED );
+}
+
+#else
+#if 0
+/* This doesn't currently work, because dup() locks the file position of the new FD with the old
+ * (which makes no sense at all), so it's not easy to read from a copy of the FD without
+ * interfering with the original. */
+class RageFileReadAheadThread
+{
+public:
+	RageFileReadAheadThread( int iFD, int iFrom, int iBytes )
+	{
+		m_iFD = iFD;
+		m_iFrom = iFrom;
+		m_iBytes = iBytes;
+		m_bFinished = false;
+
+		m_WorkerThread.SetName( "Read-ahead thread" );
+		m_WorkerThread.Create( StartWorkerMain, this );
+	}
+
+	~RageFileReadAheadThread()
+	{
+		close( m_iFD );
+		m_WorkerThread.Wait();
+	}
+	bool IsFinished() const { return m_bFinished; }
+
+private:
+	static int StartWorkerMain( void *pThis )
+	{
+		((RageFileReadAheadThread *) (pThis))->WorkerMain();
+		return 0;
+	}
+	
+	void WorkerMain()
+	{
+		RString sBuffer;
+		int iFDCopy = dup( m_iFD );
+		if( iFDCopy != -1 )
+		{
+			char *pBuf = sBuffer.GetBuffer( m_iBytes );
+			lseek( iFDCopy, m_iFrom, SEEK_SET );
+			read( iFDCopy, pBuf, m_iBytes );
+			sBuffer.ReleaseBuffer( m_iBytes );
+
+			close( iFDCopy );
+			LOG->Trace("read");
+		}
+
+		m_bFinished = true;
+	}
+
+	RageThread m_WorkerThread;
+
+	bool m_bFinished;
+	int m_iFD;
+	int m_iFrom;
+	int m_iBytes;
+};
+
+
+static vector<RageFileReadAheadThread *> g_apReadAheads;
+
+void RageFileManagerReadAhead::Init() { }
+void RageFileManagerReadAhead::Shutdown()
+{
+	for( size_t i = 0; i < g_apReadAheads.size(); ++i )
+		delete g_apReadAheads[i];
+	g_apReadAheads.clear();
+}
+
+/* This emulates posix_fadvise(POSIX_FADV_WILLNEED), to force data into cache and hint the
+ * kernel to start read-ahead from that point. */
+void RageFileManagerReadAhead::ReadAhead( RageFileBasic *pFile, int iBytes )
+{
+	int iFD = pFile->GetFD();
+	if( iFD == -1 )
+		return;
+
+	iFD = dup( iFD );
+	if( iFD == -1 )
+	{
+		LOG->Trace( "error: dup(): %s", strerror(errno) );
+		return;
+	}
+
+	int iStart = lseek( iFD, 0, SEEK_CUR );
+
+	RageFileReadAheadThread *pReadAhead = new RageFileReadAheadThread( iFD, iStart, iBytes );
+	g_apReadAheads.push_back( pReadAhead );
+	
+	for( size_t i = 0; i < g_apReadAheads.size(); ++i )
+	{
+		if( g_apReadAheads[i]->IsFinished() )
+		{
+			LOG->Trace("cleaned");
+			delete g_apReadAheads[i];
+			g_apReadAheads.erase( g_apReadAheads.begin()+i, g_apReadAheads.begin()+i+1 );
+			--i;
+		}
+	}
+}
+#else
+void RageFileManagerReadAhead::Init() { }
+void RageFileManagerReadAhead::Shutdown() { }
+void RageFileManagerReadAhead::ReadAhead( RageFileBasic *pFile, int iBytes ) { }
+#endif
+#endif
+
+#if defined(HAVE_POSIX_FADVISE)
+void RageFileManagerReadAhead::CacheHintStreaming( RageFileBasic *pFile )
+{
+	/* This guesses at the actual size of the file on disk, which may be smaller if this file is compressed.
+	 * Since this is usually used on music and video files, it generally shouldn't be. */
+	int iFD = pFile->GetFD();
+	if( iFD == -1 )
+		return;
+	int iPos = pFile->Tell();
+	int iFrom = lseek( iFD, 0, SEEK_CUR );
+	int iBytes = pFile->GetFileSize() - iPos;
+	posix_fadvise( iFD, iFrom, iBytes, POSIX_FADV_SEQUENTIAL );
+}
+#else
+void RageFileManagerReadAhead::CacheHintStreaming( RageFileBasic *pFile ) { }
+#endif
+
+
+/*
+ * Copyright (c) 2010 Glenn Maynard
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, and/or sell copies of the Software, and to permit persons to
+ * whom the Software is furnished to do so, provided that the above
+ * copyright notice(s) and this permission notice appear in all copies of
+ * the Software and that both the above copyright notice(s) and this
+ * permission notice appear in supporting documentation.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+ * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
+ * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
+ * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */