genode/repos/os/include/vfs/vfs_handle.h
Emery Hemingway 800b4e44b1 Reduce Vfs::Vfs_handle::Context to empty struct type
The "Vfs::Vfs_handle" type should not contain any public members that
can be initialized by the VFS internally and by the application, so
remove inheritance from the "Genode::list::Element" class. The VFS
plugins must instead use lists of "Vfs::Vfs_handle" sub-classes, the
lifetime of which are always managed by the plugin.

Ref #3036
2019-04-01 19:33:47 +02:00

169 lines
3.2 KiB
C++

/*
* \brief Representation of an open file
* \author Norman Feske
* \date 2011-02-17
*/
/*
* Copyright (C) 2011-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__VFS__VFS_HANDLE_H_
#define _INCLUDE__VFS__VFS_HANDLE_H_
#include <vfs/directory_service.h>
namespace Vfs{
class Vfs_handle;
class File_io_service;
class File_system;
class Vfs_watch_handle;
}
class Vfs::Vfs_handle
{
public:
/**
* Opaque handle context
*/
struct Context { };
private:
Directory_service &_ds;
File_io_service &_fs;
Genode::Allocator &_alloc;
int _status_flags;
file_size _seek = 0;
Context *_context = nullptr;
/*
* Noncopyable
*/
Vfs_handle(Vfs_handle const &);
Vfs_handle &operator = (Vfs_handle const &);
public:
class Guard
{
private:
/*
* Noncopyable
*/
Guard(Guard const &);
Guard &operator = (Guard const &);
Vfs_handle * const _handle;
public:
Guard(Vfs_handle *handle) : _handle(handle) { }
~Guard()
{
if (_handle)
_handle->close();
}
};
enum { STATUS_RDONLY = 0, STATUS_WRONLY = 1, STATUS_RDWR = 2 };
Vfs_handle(Directory_service &ds,
File_io_service &fs,
Genode::Allocator &alloc,
int status_flags)
:
_ds(ds), _fs(fs),
_alloc(alloc),
_status_flags(status_flags)
{ }
virtual ~Vfs_handle() { }
Directory_service &ds() { return _ds; }
File_io_service &fs() { return _fs; }
Allocator &alloc() { return _alloc; }
void context(Context *context) { _context = context; }
Context *context() const { return _context; }
int status_flags() const { return _status_flags; }
void status_flags(int flags) { _status_flags = flags; }
/**
* Return seek offset in bytes
*/
file_size seek() const { return _seek; }
/**
* Set seek offset in bytes
*/
void seek(file_offset seek) { _seek = seek; }
/**
* Advance seek offset by 'incr' bytes
*/
void advance_seek(file_size incr) { _seek += incr; }
/**
* Close handle at backing file-system.
*
* This leaves the handle pointer in an invalid and unsafe state.
*/
inline void close() { ds().close(this); }
};
class Vfs::Vfs_watch_handle
{
public:
/**
* Opaque handle context
*/
struct Context { };
private:
Directory_service &_fs;
Genode::Allocator &_alloc;
Context *_context = nullptr;
/*
* Noncopyable
*/
Vfs_watch_handle(Vfs_watch_handle const &);
Vfs_watch_handle &operator = (Vfs_watch_handle const &);
public:
Vfs_watch_handle(Directory_service &fs,
Genode::Allocator &alloc)
:
_fs(fs), _alloc(alloc)
{ }
virtual ~Vfs_watch_handle() { }
Directory_service &fs() { return _fs; }
Allocator &alloc() { return _alloc; }
virtual void context(Context *context) { _context = context; }
Context *context() const { return _context; }
/**
* Close handle at backing file-system.
*
* This leaves the handle pointer in an invalid and unsafe state.
*/
inline void close() { fs().close(this); }
};
#endif /* _INCLUDE__VFS__VFS_HANDLE_H_ */