tkrzw::PositionalFile Class Reference

Interface for positional access file implementations. More...

#include <tkrzw_file_pos.h>

Public Types
enum	AccessOption : int32_t { ACCESS_DEFAULT = 0, ACCESS_DIRECT = 1 << 0, ACCESS_SYNC = 1 << 1, ACCESS_PADDING = 1 << 2 }
	Enumeration of options for SetAccessStrategy. More...
Public Types inherited from tkrzw::File
enum	OpenOption : int32_t {   OPEN_DEFAULT = 0, OPEN_TRUNCATE = 1 << 0, OPEN_NO_CREATE = 1 << 1, OPEN_NO_WAIT = 1 << 2,   OPEN_NO_LOCK = 1 << 3 }
	Enumeration of options for Open. More...

Public Member Functions
virtual	~PositionalFile ()=default
	Destructor. More...
virtual Status	SetHeadBuffer (int64_t size)=0
	Sets the head buffer to cache the beginning region of the file. More...
virtual Status	SetAccessStrategy (int64_t block_size, int32_t options)=0
	Sets access strategy. More...
virtual int64_t	GetBlockSize () const =0
	Gets the block size. More...
virtual bool	IsDirectIO () const =0
	Checks whether the access mode is direct I/O. More...
Public Member Functions inherited from tkrzw::File
virtual	~File ()=default
	Destructor. More...
virtual Status	Open (const std::string &path, bool writable, int32_t options=OPEN_DEFAULT)=0
	Opens a file. More...
virtual Status	Close ()=0
	Closes the file. More...
virtual Status	Read (int64_t off, void *buf, size_t size)=0
	Reads data. More...
virtual std::string	ReadSimple (int64_t off, size_t size)
	Reads data, in a simple way. More...
virtual Status	Write (int64_t off, const void *buf, size_t size)=0
	Writes data. More...
virtual bool	WriteSimple (int64_t off, std::string_view data)
	Writes data, in a simple way. More...
virtual Status	Append (const void *buf, size_t size, int64_t *off=nullptr)=0
	Appends data at the end of the file. More...
virtual int64_t	AppendSimple (const std::string &data)
	Appends data at the end of the file, in a simple way. More...
virtual Status	Expand (size_t inc_size, int64_t *old_size=nullptr)=0
	Expands the file size without writing data. More...
virtual int64_t	ExpandSimple (size_t inc_size)
	Expands the file size without writing data, in a simple way. More...
virtual Status	Truncate (int64_t size)=0
	Truncates the file. More...
virtual Status	TruncateFakely (int64_t size)=0
	Truncate the file fakely. More...
virtual Status	Synchronize (bool hard)=0
	Synchronizes the content of the file to the file system. More...
virtual Status	GetSize (int64_t *size)=0
	Gets the size of the file. More...
virtual int64_t	GetSizeSimple ()
	Gets the size of the file, in a simple way. More...
virtual Status	SetAllocationStrategy (int64_t init_size, double inc_factor)=0
	Sets allocation strategy. More...
virtual Status	CopyProperties (File *file)=0
	Copies internal properties to another file object. More...
virtual Status	GetPath (std::string *path)=0
	Gets the path of the file. More...
virtual std::string	GetPathSimple ()
	Gets the path of the file, in a simple way. More...
virtual Status	Rename (const std::string &new_path)=0
	Renames the file. More...
virtual Status	DisablePathOperations ()=0
	Disables operations related to the path. More...
virtual bool	IsMemoryMapping () const =0
	Checks whether operations are done by memory mapping. More...
virtual bool	IsAtomic () const =0
	Checks whether updating operations are atomic and thread-safe. More...
virtual std::unique_ptr< File >	MakeFile () const =0
	Makes a new file object of the same concrete class. More...

Additional Inherited Members
Static Public Attributes inherited from tkrzw::File
static constexpr int64_t	DEFAULT_ALLOC_INIT_SIZE = 1LL << 20
	The default value of the initial allocation size. More...
static constexpr double	DEFAULT_ALLOC_INC_FACTOR = 2.0
	The default value of the allocation increment factor. More...

Detailed Description

Interface for positional access file implementations.

Member Enumeration Documentation

AccessOption

enum tkrzw::PositionalFile::AccessOption : int32_t

Enumeration of options for SetAccessStrategy.

Enumerator
ACCESS_DEFAULT	The default behavior.
ACCESS_DIRECT	To access the data block directry without caching.
ACCESS_SYNC	To synchronize the update operation through the device.
ACCESS_PADDING	To fill padding bytes for alignment when closing the file.

Constructor & Destructor Documentation

~PositionalFile()

virtual tkrzw::PositionalFile::~PositionalFile ( )

virtualdefault

Destructor.

Member Function Documentation

SetHeadBuffer()

virtual Status tkrzw::PositionalFile::SetHeadBuffer ( int64_t  size )

pure virtual

Sets the head buffer to cache the beginning region of the file.

Parameters

size	The size of the head buffer. If it is not positive, it is not used.

Returns

The result status. This method must be called after the file is opened.

Implemented in tkrzw::PositionalAtomicFile, and tkrzw::PositionalParallelFile.

SetAccessStrategy()

virtual Status tkrzw::PositionalFile::SetAccessStrategy ( int64_t  block_size, int32_t  options  )

pure virtual

Sets access strategy.

Parameters

block_size	The block size to which all blocks should be aligned. It must be a multiple of the block size of the underlying file system or device.
options	Bit-sum options of PositionalFile::AccessOption enums;

Returns

The result status.

Implemented in tkrzw::PositionalAtomicFile, and tkrzw::PositionalParallelFile.

GetBlockSize()

virtual int64_t tkrzw::PositionalFile::GetBlockSize ( ) const

pure virtual

Gets the block size.

Returns

the block size.

Implemented in tkrzw::PositionalAtomicFile, and tkrzw::PositionalParallelFile.

IsDirectIO()

virtual bool tkrzw::PositionalFile::IsDirectIO ( ) const

pure virtual

Checks whether the access mode is direct I/O.

Returns

True if the access mode is direct I/O, or false if not.

Implemented in tkrzw::PositionalAtomicFile, and tkrzw::PositionalParallelFile.