Stxxl: file Class Reference

Stxxl 1.3.2

Defines interface of file. More...

#include <file.h>

Inheritance diagram for file:

Inheritance graph

Public Types
enum	open_mode { RDONLY = 1, WRONLY = 2, RDWR = 4, CREAT = 8, DIRECT = 16, TRUNC = 32, SYNC = 64, NO_LOCK = 128 }
	Definition of acceptable file open modes. More...

typedef request::offset_type	offset_type

typedef request::size_type	size_type

Public Member Functions
virtual request_ptr	aread (void *buffer, offset_type pos, size_type bytes, const completion_handler &on_cmpl)=0
	Schedules an asynchronous read request to the file. More...

virtual request_ptr	awrite (void *buffer, offset_type pos, size_type bytes, const completion_handler &on_cmpl)=0
	Schedules an asynchronous write request to the file. More...

virtual void	serve (const request *req)=0 throw (io_error)

void	add_request_ref ()

void	delete_request_ref ()

int	get_request_nref ()

virtual void	set_size (offset_type newsize)=0
	Changes the size of the file. More...

virtual offset_type	size ()=0
	Returns size of the file. More...

virtual int	get_queue_id () const =0
	Returns the identifier of the file's queue. More...

virtual int	get_allocator_id () const =0
	Returns the file's allocator. More...

virtual int	get_physical_device_id () const

virtual void	lock ()=0
	Locks file for reading and writing (acquires a lock in the file system) More...

virtual void	discard (offset_type offset, offset_type size)
	Discard a region of the file (mark it unused) some specialized file types may need to know freed regions. More...

virtual void	export_files (offset_type offset, offset_type length, std::string prefix)

virtual void	remove ()

virtual const char *	io_type () const
	Identifies the type of I/O implementation. More...

Static Public Attributes
static const int	DEFAULT_QUEUE = -1

static const int	NO_QUEUE = -2

static const int	NO_ALLOCATOR = -1

Protected Member Functions
	file ()
	Initializes file object. More...

Detailed Description

Defines interface of file.

It is a base class for different implementations that might base on various file systems or even remote storage interfaces

Examples:: io/test_cancel.cpp, and io/test_io_sizes.cpp.

Member Enumeration Documentation

enum file::open_mode

Definition of acceptable file open modes.

Various open modes in a file system must be converted to this set of acceptable modes

Enumerator
RDONLY	only reading of the file is allowed
WRONLY	only writing of the file is allowed
RDWR	read and write of the file are allowed
CREAT	in case file does not exist no error occurs and file is newly created
DIRECT	I/Os proceed bypassing file system buffers, i.e. unbuffered I/O.
TRUNC	once file is opened its length becomes zero
SYNC	open the file with O_SYNC \| O_DSYNC \| O_RSYNC flags set
NO_LOCK	do not aquire an exclusive lock by default

Constructor & Destructor Documentation

file::file ( )

inlineprotected

Initializes file object.

Parameters

_id	file identifier

Remarks: Called in implementations of file

Member Function Documentation

virtual request_ptr file::aread	(	void *	buffer,
		offset_type	pos,
		size_type	bytes,
		const completion_handler &	on_cmpl
	)

pure virtual

Schedules an asynchronous read request to the file.

Parameters

buffer	pointer to memory buffer to read into
pos	file position to start read from
bytes	number of bytes to transfer
on_cmpl	I/O completion handler

Returns: request_ptr request object, which can be used to track the status of the operation

Implemented in disk_queued_file.

Referenced by typed_block< RawSize_, T_, NRef_, InfoType_ >::read().

virtual request_ptr file::awrite	(	void *	buffer,
		offset_type	pos,
		size_type	bytes,
		const completion_handler &	on_cmpl
	)

pure virtual

Schedules an asynchronous write request to the file.

Parameters

buffer	pointer to memory buffer to write from
pos	starting file position to write
bytes	number of bytes to transfer
on_cmpl	I/O completion handler

Returns: request_ptr request object, which can be used to track the status of the operation

Implemented in disk_queued_file.

Examples:: io/test_cancel.cpp.

Referenced by typed_block< RawSize_, T_, NRef_, InfoType_ >::write().

virtual void file::discard	(	offset_type	offset,
		offset_type	size
	)

inlinevirtual

Discard a region of the file (mark it unused) some specialized file types may need to know freed regions.

Reimplemented in fileperblock_file< base_file_type >, and mem_file.

Referenced by block_manager::delete_block().

virtual int file::get_allocator_id ( ) const

pure virtual

Returns the file's allocator.

Returns: allocator number

Implemented in disk_queued_file.

Referenced by block_manager::delete_block().

virtual int file::get_queue_id ( ) const

pure virtual

Returns the identifier of the file's queue.

Remarks: Files allocated on the same physical device usually share the same queue

Returns: queue number

Implemented in disk_queued_file.

Referenced by request_with_state::cancel().

virtual const char* file::io_type ( ) const

inlinevirtual

Identifies the type of I/O implementation.

Returns: pointer to null terminated string of characters, containing the name of I/O implementation

Reimplemented in sim_disk_file, wbtl_file, fileperblock_file< base_file_type >, mmap_file, ufs_file_base, mem_file, and syscall_file.

Referenced by serving_request::io_type().

virtual void file::lock ( )

pure virtual

Locks file for reading and writing (acquires a lock in the file system)

Implemented in wbtl_file, fileperblock_file< base_file_type >, ufs_file_base, and mem_file.

virtual void file::set_size ( offset_type newsize )

pure virtual

Changes the size of the file.

Parameters

newsize new file size

Implemented in sim_disk_file, fileperblock_file< base_file_type >, ufs_file_base, and mem_file.

Examples:: io/test_cancel.cpp.

Referenced by vector< Tp_, PgSz_, PgTp_, BlkSize_, AllocStr_, SzTp_ >::vector().

virtual offset_type file::size ( )

pure virtual

Returns size of the file.

Returns: file size in bytes

Implemented in wbtl_file, fileperblock_file< base_file_type >, ufs_file_base, and mem_file.

The documentation for this class was generated from the following file:

file.h