321 lines
6.6 KiB
C++
321 lines
6.6 KiB
C++
/*
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Copyright (C) 2010 Paul Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <cassert>
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#include <cstdio>
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#ifdef __APPLE__
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#include <mach/mach_time.h>
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#endif
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#include "pbd/compose.h"
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#include "pbd/file_manager.h"
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#include "pbd/resource.h"
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#include "pbd/debug.h"
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using namespace std;
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using namespace PBD;
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FileManager* FileDescriptor::_manager;
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FileManager::FileManager ()
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: _open (0)
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{
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struct ResourceLimit rl;
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/* XXX: this is a bit arbitrary */
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if (get_resource_limit (OpenFiles, rl)) {
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_max_open = rl.current_limit - 64;
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} else {
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_max_open = 256;
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}
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DEBUG_TRACE (DEBUG::FileManager, string_compose ("FileManager can open up to %1 files.\n", _max_open));
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}
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void
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FileManager::add (FileDescriptor* d)
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{
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Glib::Threads::Mutex::Lock lm (_mutex);
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_files.push_back (d);
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}
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/** @return true on error, otherwise false */
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bool
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FileManager::allocate (FileDescriptor* d)
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{
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Glib::Threads::Mutex::Lock lm (_mutex);
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if (!d->is_open()) {
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/* this file needs to be opened */
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if (_open == _max_open) {
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/* We already have the maximum allowed number of files opened, so we must try to close one.
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Find the unallocated, open file with the lowest last_used time.
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*/
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double lowest_last_used = DBL_MAX;
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list<FileDescriptor*>::iterator oldest = _files.end ();
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for (list<FileDescriptor*>::iterator i = _files.begin(); i != _files.end(); ++i) {
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if ((*i)->is_open() && (*i)->_refcount == 0) {
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if ((*i)->_last_used < lowest_last_used) {
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lowest_last_used = (*i)->_last_used;
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oldest = i;
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}
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}
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}
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if (oldest == _files.end()) {
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/* no unallocated and open files exist, so there's nothing we can do */
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return true;
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}
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close (*oldest);
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DEBUG_TRACE (
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DEBUG::FileManager,
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string_compose (
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"closed file for %1 to release file handle; now have %2 of %3 open\n",
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(*oldest)->_path, _open, _max_open
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)
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);
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}
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if (d->open ()) {
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DEBUG_TRACE (DEBUG::FileManager, string_compose ("open of %1 failed.\n", d->_path));
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return true;
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}
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_open++;
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DEBUG_TRACE (DEBUG::FileManager, string_compose ("opened file for %1; now have %2 of %3 open.\n", d->_path, _open, _max_open));
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}
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#ifdef __APPLE__
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d->_last_used = mach_absolute_time();
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#elif defined(_POSIX_TIMERS) && defined(_POSIX_MONOTONIC_CLOCK)
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struct timespec t;
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clock_gettime (CLOCK_MONOTONIC, &t);
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d->_last_used = t.tv_sec + (double) t.tv_nsec / 10e9;
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#else
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struct timeval now;
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gettimeofday (&now, NULL);
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d->_last_used = now.tv_sec + (double) now.tv_usec / 10e6;
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#endif
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d->_refcount++;
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return false;
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}
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/** Tell FileManager that a FileDescriptor is no longer needed for a given handle */
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void
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FileManager::release (FileDescriptor* d)
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{
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Glib::Threads::Mutex::Lock lm (_mutex);
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d->_refcount--;
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assert (d->_refcount >= 0);
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}
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/** Remove a file from our lists. It will be closed if it is currently open. */
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void
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FileManager::remove (FileDescriptor* d)
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{
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Glib::Threads::Mutex::Lock lm (_mutex);
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if (d->is_open ()) {
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close (d);
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DEBUG_TRACE (
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DEBUG::FileManager,
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string_compose ("closed file for %1; file is being removed; now have %2 of %3 open\n", d->_path, _open, _max_open)
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);
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}
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_files.remove (d);
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}
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void
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FileManager::close (FileDescriptor* d)
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{
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/* we must have a lock on our mutex */
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d->close ();
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d->Closed (); /* EMIT SIGNAL */
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_open--;
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}
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FileDescriptor::FileDescriptor (string const & n, bool w)
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: _refcount (0)
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, _last_used (0)
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, _path (n)
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, _writeable (w)
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{
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}
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FileManager*
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FileDescriptor::manager ()
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{
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if (_manager == 0) {
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_manager = new FileManager;
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}
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return _manager;
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}
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/** Release a previously allocated handle to this file */
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void
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FileDescriptor::release ()
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{
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manager()->release (this);
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}
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/** @param file_name Filename.
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* @param writeable true to open writeable, otherwise false.
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* @param mode Open mode for the file.
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*/
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FdFileDescriptor::FdFileDescriptor (string const & file_name, bool writeable, mode_t mode)
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: FileDescriptor (file_name, writeable)
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, _fd (-1)
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, _mode (mode)
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{
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manager()->add (this);
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}
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FdFileDescriptor::~FdFileDescriptor ()
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{
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manager()->remove (this);
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}
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bool
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FdFileDescriptor::is_open () const
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{
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/* we must have a lock on the FileManager's mutex */
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return _fd != -1;
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}
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bool
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FdFileDescriptor::open ()
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{
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/* we must have a lock on the FileManager's mutex */
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_fd = ::open (_path.c_str(), _writeable ? (O_RDWR | O_CREAT) : O_RDONLY, _mode);
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return (_fd == -1);
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}
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void
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FdFileDescriptor::close ()
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{
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/* we must have a lock on the FileManager's mutex */
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::close (_fd);
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_fd = -1;
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}
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/** @return fd, or -1 on error */
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int
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FdFileDescriptor::allocate ()
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{
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bool const f = manager()->allocate (this);
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if (f) {
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return -1;
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}
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/* this is ok thread-wise because allocate () has incremented
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the Descriptor's refcount, so the file will not be closed
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*/
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return _fd;
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}
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void
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FileDescriptor::set_path (const string& p)
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{
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_path = p;
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}
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/** @param file_name Filename.
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* @param mode Mode to pass to fopen.
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*/
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StdioFileDescriptor::StdioFileDescriptor (string const & file_name, std::string const & mode)
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: FileDescriptor (file_name, false)
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, _file (0)
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, _mode (mode)
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{
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manager()->add (this);
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}
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StdioFileDescriptor::~StdioFileDescriptor ()
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{
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manager()->remove (this);
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}
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bool
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StdioFileDescriptor::is_open () const
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{
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/* we must have a lock on the FileManager's mutex */
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return _file != 0;
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}
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bool
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StdioFileDescriptor::open ()
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{
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/* we must have a lock on the FileManager's mutex */
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_file = fopen (_path.c_str(), _mode.c_str());
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return (_file == 0);
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}
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void
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StdioFileDescriptor::close ()
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{
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/* we must have a lock on the FileManager's mutex */
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fclose (_file);
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_file = 0;
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}
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/** @return FILE*, or 0 on error */
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FILE*
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StdioFileDescriptor::allocate ()
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{
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bool const f = manager()->allocate (this);
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if (f) {
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return 0;
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}
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/* this is ok thread-wise because allocate () has incremented
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the Descriptor's refcount, so the file will not be closed
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*/
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return _file;
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}
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