Move FileManager code into libpbd. Use it for SMF read/write.

git-svn-id: svn://localhost/ardour2/branches/3.0@7108 d708f5d6-7413-0410-9779-e7cbd77b26cf

5 files changed, 538 insertions, 0 deletions

diff --git a/libs/pbd/debug.cc b/libs/pbd/debug.cc
index 318f85a099..4f97ccff86 100644
--- a/libs/pbd/debug.cc
+++ b/libs/pbd/debug.cc
@@ -32,6 +32,7 @@ static std::map<const char*,uint64_t> _debug_bit_map;
 
 uint64_t PBD::DEBUG::Stateful = PBD::new_debug_bit ("stateful");
 uint64_t PBD::DEBUG::Properties = PBD::new_debug_bit ("properties");
+uint64_t PBD::DEBUG::FileManager = PBD::new_debug_bit ("filemanager");
 
 uint64_t PBD::debug_bits = 0x0;
 
diff --git a/libs/pbd/file_manager.cc b/libs/pbd/file_manager.cc
new file mode 100644
index 0000000000..25d171b959
--- /dev/null
+++ b/libs/pbd/file_manager.cc
@@ -0,0 +1,386 @@
+/*
+    Copyright (C) 2010 Paul Davis
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <cassert>
+#include <iostream>
+#include "pbd/compose.h"
+#include "pbd/file_manager.h"
+#include "pbd/debug.h"
+
+using namespace std;
+using namespace PBD;
+
+FileManager* FileDescriptor::_manager;
+
+namespace PBD {
+
+/** Class to limit the number of files held open */
+class FileManager
+{
+public:
+	FileManager ();
+	
+	void add (FileDescriptor *);
+	void remove (FileDescriptor *);
+
+	void release (FileDescriptor *);
+	bool allocate (FileDescriptor *);
+
+private:
+	
+	void close (FileDescriptor *);
+
+	std::list<FileDescriptor*> _files; ///< files we know about
+	Glib::Mutex _mutex; ///< mutex for _files, _open and FileDescriptor contents
+	int _open; ///< number of open files
+	int _max_open; ///< maximum number of open files
+};
+
+}
+
+FileManager::FileManager ()
+	: _open (0)
+{
+	struct rlimit rl;
+	int const r = getrlimit (RLIMIT_NOFILE, &rl);
+	
+	/* XXX: this is a bit arbitrary */
+	if (r == 0) {
+		_max_open = rl.rlim_cur - 64;
+	} else {
+		_max_open = 256;
+	}
+
+	DEBUG_TRACE (DEBUG::FileManager, string_compose ("FileManager can open up to %1 files.\n", _max_open));
+}
+
+void
+FileManager::add (FileDescriptor* d)
+{
+	Glib::Mutex::Lock lm (_mutex);
+	_files.push_back (d);
+}
+
+/** @return true on error, otherwise false */
+bool
+FileManager::allocate (FileDescriptor* d)
+{
+	Glib::Mutex::Lock lm (_mutex);
+
+	if (!d->is_open()) {
+		
+		/* this file needs to be opened */
+		
+		if (_open == _max_open) {
+
+			/* We already have the maximum allowed number of files opened, so we must try to close one.
+			   Find the unallocated, open file with the lowest last_used time.
+			*/
+
+			double lowest_last_used = DBL_MAX;
+			list<FileDescriptor*>::iterator oldest = _files.end ();
+
+			for (list<FileDescriptor*>::iterator i = _files.begin(); i != _files.end(); ++i) {
+				if ((*i)->is_open() && (*i)->_refcount == 0) {
+					if ((*i)->_last_used < lowest_last_used) {
+						lowest_last_used = (*i)->_last_used;
+						oldest = i;
+					}
+				}
+			}
+
+			if (oldest == _files.end()) {
+				/* no unallocated and open files exist, so there's nothing we can do */
+				return true;
+			}
+
+			close (*oldest);
+			DEBUG_TRACE (
+				DEBUG::FileManager,
+				string_compose (
+					"closed file for %1 to release file handle; now have %2 of %3 open\n",
+					(*oldest)->_name, _open, _max_open
+					)
+				);
+		}
+
+		if (d->open ()) {
+			DEBUG_TRACE (DEBUG::FileManager, string_compose ("open of %1 failed.\n", d->_name));
+			return true;
+		}
+
+		_open++;
+
+		DEBUG_TRACE (DEBUG::FileManager, string_compose ("opened file for %1; now have %2 of %3 open.\n", d->_name, _open, _max_open));
+	}
+
+	struct timespec t;
+	clock_gettime (CLOCK_MONOTONIC, &t);
+	d->_last_used = t.tv_sec + (double) t.tv_nsec / 10e9;
+
+	d->_refcount++;
+	
+	return false;
+}
+
+/** Tell FileManager that a FileDescriptor is no longer needed for a given handle */
+void
+FileManager::release (FileDescriptor* d)
+{
+	Glib::Mutex::Lock lm (_mutex);
+
+	d->_refcount--;
+	assert (d->_refcount >= 0);
+}
+
+/** Remove a file from our lists.  It will be closed if it is currently open. */
+void
+FileManager::remove (FileDescriptor* d)
+{
+	Glib::Mutex::Lock lm (_mutex);
+
+	if (d->is_open ()) {
+		close (d);
+		DEBUG_TRACE (
+			DEBUG::FileManager,
+			string_compose ("closed file for %1; file is being removed; now have %2 of %3 open\n", d->_name, _open, _max_open)
+			);
+	}
+
+	_files.remove (d);
+}
+
+void
+FileManager::close (FileDescriptor* d)
+{
+	/* we must have a lock on our mutex */
+
+	d->close ();
+	d->Closed (); /* EMIT SIGNAL */
+	_open--;
+}
+
+FileDescriptor::FileDescriptor (string const & n, bool w)
+	: _refcount (0)
+	, _last_used (0)
+	, _name (n)
+	, _writeable (w)
+{
+
+}
+
+FileManager*
+FileDescriptor::manager ()
+{
+	if (_manager == 0) {
+		_manager = new FileManager;
+	}
+
+	return _manager;
+}
+
+/** Release a previously allocated handle to this file */
+void
+FileDescriptor::release ()
+{
+	manager()->release (this);
+}
+
+/** @param n Filename.
+ *  @param w true to open writeable, otherwise false.
+ *  @param i SF_INFO for the file.
+ */
+
+SndFileDescriptor::SndFileDescriptor (string const & n, bool w, SF_INFO* i)
+	: FileDescriptor (n, w)
+	, _sndfile (0)
+	, _info (i)
+{
+	manager()->add (this);
+}
+
+SndFileDescriptor::~SndFileDescriptor ()
+{
+	manager()->remove (this);
+}
+
+/** @return SNDFILE*, or 0 on error */
+SNDFILE*
+SndFileDescriptor::allocate ()
+{
+	bool const f = manager()->allocate (this);
+	if (f) {
+		return 0;
+	}
+
+	/* this is ok thread-wise because allocate () has incremented
+	   the Descriptor's refcount, so the file will not be closed
+	*/
+	return _sndfile;
+}
+
+void
+SndFileDescriptor::close ()
+{
+	/* we must have a lock on the FileManager's mutex */
+
+	sf_close (_sndfile);
+	_sndfile = 0;
+}
+
+bool
+SndFileDescriptor::is_open () const
+{
+	/* we must have a lock on the FileManager's mutex */
+
+	return _sndfile != 0;
+}
+
+bool
+SndFileDescriptor::open ()
+{
+	/* we must have a lock on the FileManager's mutex */
+	
+	_sndfile = sf_open (_name.c_str(), _writeable ? SFM_RDWR : SFM_READ, _info);
+	return (_sndfile == 0);
+}
+
+
+/** @param n Filename.
+ *  @param w true to open writeable, otherwise false.
+ *  @param m Open mode for the file.
+ */
+
+FdFileDescriptor::FdFileDescriptor (string const & n, bool w, mode_t m)
+	: FileDescriptor (n, w)
+	, _fd (-1)
+	, _mode (m)
+{
+	manager()->add (this);
+}
+
+FdFileDescriptor::~FdFileDescriptor ()
+{
+	manager()->remove (this);
+}
+
+bool
+FdFileDescriptor::is_open () const
+{
+	/* we must have a lock on the FileManager's mutex */
+
+	return _fd != -1;
+}
+
+bool
+FdFileDescriptor::open ()
+{
+	/* we must have a lock on the FileManager's mutex */
+	
+	_fd = ::open (_name.c_str(), _writeable ? (O_RDWR | O_CREAT) : O_RDONLY, _mode);
+	return (_fd == -1);
+}
+
+void
+FdFileDescriptor::close ()
+{
+	/* we must have a lock on the FileManager's mutex */
+
+	::close (_fd);
+	_fd = -1;
+}
+
+/** @return fd, or -1 on error */
+int
+FdFileDescriptor::allocate ()
+{
+	bool const f = manager()->allocate (this);
+	if (f) {
+		return -1;
+	}
+
+	/* this is ok thread-wise because allocate () has incremented
+	   the Descriptor's refcount, so the file will not be closed
+	*/
+	return _fd;
+}
+
+
+/** @param n Filename.
+ *  @param w true to open writeable, otherwise false.
+ */
+
+StdioFileDescriptor::StdioFileDescriptor (string const & n, std::string const & m)
+	: FileDescriptor (n, false)
+	, _file (0)
+	, _mode (m)
+{
+	manager()->add (this);
+}
+
+StdioFileDescriptor::~StdioFileDescriptor ()
+{
+	manager()->remove (this);
+}
+
+bool
+StdioFileDescriptor::is_open () const
+{
+	/* we must have a lock on the FileManager's mutex */
+
+	return _file != 0;
+}
+
+bool
+StdioFileDescriptor::open ()
+{
+	/* we must have a lock on the FileManager's mutex */
+	
+	_file = fopen (_name.c_str(), _mode.c_str());
+	return (_file == 0);
+}
+
+void
+StdioFileDescriptor::close ()
+{
+	/* we must have a lock on the FileManager's mutex */
+
+	fclose (_file);
+	_file = 0;
+}
+
+/** @return FILE*, or 0 on error */
+FILE*
+StdioFileDescriptor::allocate ()
+{
+	bool const f = manager()->allocate (this);
+	if (f) {
+		return 0;
+	}
+
+	/* this is ok thread-wise because allocate () has incremented
+	   the Descriptor's refcount, so the file will not be closed
+	*/
+	return _file;
+}
diff --git a/libs/pbd/pbd/debug.h b/libs/pbd/pbd/debug.h
index a45a867bd2..d3ce495a1b 100644
--- a/libs/pbd/pbd/debug.h
+++ b/libs/pbd/pbd/debug.h
@@ -39,6 +39,7 @@ namespace PBD {
                 
                 extern uint64_t Stateful;
                 extern uint64_t Properties;
+		extern uint64_t FileManager;
 	}
 }
 
diff --git a/libs/pbd/pbd/file_manager.h b/libs/pbd/pbd/file_manager.h
new file mode 100644
index 0000000000..3f708eb44e
--- /dev/null
+++ b/libs/pbd/pbd/file_manager.h
@@ -0,0 +1,149 @@
+/*
+    Copyright (C) 2010 Paul Davis
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef __pbd_file_manager_h__
+#define __pbd_file_manager_h__
+
+#include <sys/types.h>
+#include <string>
+#include <map>
+#include <sndfile.h>
+#include <glibmm/thread.h>
+#include "pbd/signals.h"
+
+namespace PBD {
+
+class FileManager;
+
+/** Parent class for FileDescriptors.
+ *
+ *  When a subclass is instantiated, the file it describes is added to a
+ *  list.  The FileDescriptor can be `allocated', meaning that its
+ *  file will be opened on the filesystem, and can then be `released'.
+ *  FileDescriptors are reference counted as they are allocated and
+ *  released.  When a descriptor's refcount is 0, the file on the
+ *  filesystem is eligible to be closed if necessary to free up file
+ *  handles for other files.
+ *
+ *  The upshot of all this is that Ardour can manage the number of
+ *  open files to stay within limits imposed by the operating system.
+ */
+	
+class FileDescriptor
+{
+public:
+	FileDescriptor (std::string const &, bool);
+	virtual ~FileDescriptor () {}
+
+	void release ();
+
+	/** Emitted when the file is closed */
+	PBD::Signal0<void> Closed;
+
+protected:
+
+	friend class FileManager;
+
+	/* These methods and variables must be called / accessed
+	   with a lock held on the FileManager's mutex
+	*/
+
+	/** @return false on success, true on failure */
+	virtual bool open () = 0;
+	virtual void close () = 0;
+	virtual bool is_open () const = 0;
+
+	int _refcount; ///< number of active users of this file
+	double _last_used; ///< monotonic time that this file was last allocated
+	std::string _name; ///< filename
+	bool _writeable; ///< true if it should be opened writeable, otherwise false
+
+	FileManager* manager ();
+	
+private:
+	
+	static FileManager* _manager;
+};
+
+/** FileDescriptor for a file to be opened using libsndfile */	
+class SndFileDescriptor : public FileDescriptor
+{
+public:
+	SndFileDescriptor (std::string const &, bool, SF_INFO *);
+	~SndFileDescriptor ();
+
+	SNDFILE* allocate ();
+
+private:	
+
+	friend class FileManager;
+
+	bool open ();
+	void close ();
+	bool is_open () const;
+
+	SNDFILE* _sndfile; ///< SNDFILE* pointer, or 0 if the file is closed
+	SF_INFO* _info; ///< libsndfile's info for this file
+};
+
+/** FileDescriptor for a file to be opened using POSIX open */	
+class FdFileDescriptor : public FileDescriptor
+{
+public:
+	FdFileDescriptor (std::string const &, bool, mode_t);
+	~FdFileDescriptor ();
+
+	int allocate ();
+
+private:
+
+	friend class FileManager;
+
+	bool open ();
+	void close ();
+	bool is_open () const;
+
+	int _fd; ///< file descriptor, or -1 if the file is closed
+	mode_t _mode; ///< mode to use when creating files
+};
+
+/** FileDescriptor for a file opened using stdio */
+class StdioFileDescriptor : public FileDescriptor
+{
+public:
+	StdioFileDescriptor (std::string const &, std::string const &);
+	~StdioFileDescriptor ();
+
+	FILE* allocate ();
+
+private:
+
+	friend class FileManager;
+
+	bool open ();
+	void close ();
+	bool is_open () const;
+
+	FILE* _file;
+	std::string _mode;
+};
+
+}
+
+#endif
diff --git a/libs/pbd/wscript b/libs/pbd/wscript
index 81174d1262..73d6c3023c 100644
--- a/libs/pbd/wscript
+++ b/libs/pbd/wscript
@@ -67,6 +67,7 @@ def build(bld):
 		error.cc
 		filesystem.cc
 		filesystem_paths.cc
+		file_manager.cc
 		file_utils.cc
 		fpu.cc
 		id.cc