tkrzw::FileIndex Class Reference

File secondary index implementation with TreeDBM. More...

#include <tkrzw_index.h>

Classes
class	Iterator
	Iterator for each record. More...

Public Member Functions
	FileIndex ()
	Default constructor. More...
	FileIndex (std::unique_ptr< File > file)
	Constructor with a file object. More...
	FileIndex (const FileIndex &rhs)=delete
	Copy and assignment are disabled. More...
FileIndex &	operator= (const FileIndex &rhs)=delete
Status	Open (const std::string &path, bool writable, int32_t options=File::OPEN_DEFAULT, const TreeDBM::TuningParameters &tuning_params=TreeDBM::TuningParameters())
	Opens an index file. More...
Status	Close ()
	Closes the index file. More...
bool	Check (std::string_view key, std::string_view value)
	Checks whether a record exists in the index. More...
std::vector< std::string >	GetValues (std::string_view key, size_t max=0)
	Gets all values of records of a key. More...
Status	Add (std::string_view key, std::string_view value)
	Adds a record. More...
Status	Remove (std::string_view key, std::string_view value)
	Removes a record. More...
size_t	Count ()
	Gets the number of records. More...
std::string	GetFilePath ()
	Gets the path of the index file. More...
Status	Clear ()
	Removes all records. More...
Status	Rebuild ()
	Rebuilds the entire index. More...
Status	Synchronize (bool hard)
	Synchronizes the content of the index to the file system. More...
bool	IsOpen () const
	Checks whether the index is open. More...
bool	IsWritable () const
	Checks whether the index is writable. More...
TreeDBM *	GetInternalDBM () const
	Gets the pointer to the internal database object. More...
std::unique_ptr< Iterator >	MakeIterator ()
	Makes an iterator for each record. More...

Detailed Description

File secondary index implementation with TreeDBM.

All operations are thread-safe; Multiple threads can access the same index concurrently. Every opened index must be closed explicitly to avoid data corruption.

Constructor & Destructor Documentation

FileIndex() [1/3]

tkrzw::FileIndex::FileIndex

(

)

Default constructor.

MemoryMapParallelFile is used to handle the data.

FileIndex() [2/3]

tkrzw::FileIndex::FileIndex ( std::unique_ptr< File >  file )

explicit

Constructor with a file object.

Parameters

file	The file object to handle the data. The ownership is taken.

FileIndex() [3/3]

tkrzw::FileIndex::FileIndex ( const FileIndex &  rhs )

explicitdelete

Copy and assignment are disabled.

Member Function Documentation

Open()

Status tkrzw::FileIndex::Open	(	const std::string &	path,
		bool	writable,
		int32_t	options = File::OPEN_DEFAULT,
		const TreeDBM::TuningParameters &	tuning_params = TreeDBM::TuningParameters()
	)

Opens an index file.

Parameters

path	A path of the file.
writable	If true, the file is writable. If false, it is read-only.
options	Bit-sum options for opening the file.
tuning_params	A structure for tuning parameters.

Returns

The result status.

If the key comparator of the tuning parameter is nullptr, PairLexicalKeyComparator is set implicitly. Other compatible key comparators are PairLexicalCaseKeyComparator, PairDecimalKeyComparator, PairHexadecimalKeyComparator, PairRealNumberKeyComparator, PairSignedBigEndianKeyComparator, and PairFloatBigEndianKeyComparator. The alignment power and the maximum page size are also set implicitly to be suitable for random access.

Close()

Status tkrzw::FileIndex::Close

(

)

Closes the index file.

Returns

The result status.

Check()

bool tkrzw::FileIndex::Check	(	std::string_view	key,
		std::string_view	value
	)

Checks whether a record exists in the index.

Parameters

key	The key of the record.
value	The value of the record.

GetValues()

std::vector< std::string > tkrzw::FileIndex::GetValues	(	std::string_view	key,
		size_t	max = 0
	)

Gets all values of records of a key.

Parameters

key	The key to look for.
max	The maximum number of values to get. 0 means unlimited.

Returns

All values of the key. An empty vector is returned on failure.

Add()

Status tkrzw::FileIndex::Add	(	std::string_view	key,
		std::string_view	value
	)

Adds a record.

Parameters

key	The key of the record. This can be an arbitrary expression to search the index.
value	The value of the record. This should be a primary value of another database.

Returns

The result status.

Remove()

Status tkrzw::FileIndex::Remove	(	std::string_view	key,
		std::string_view	value
	)

Removes a record.

Parameters

key	The key of the record.
value	The value of the record.

Returns

The result status.

Count()

size_t tkrzw::FileIndex::Count

(

)

Gets the number of records.

Returns

The number of records, or -1 on failure.

GetFilePath()

std::string tkrzw::FileIndex::GetFilePath

(

)

Gets the path of the index file.

Returns

The file path of the index, or an empty string on failure.

Clear()

Status tkrzw::FileIndex::Clear

(

)

Removes all records.

Returns

The result status.

Rebuild()

Status tkrzw::FileIndex::Rebuild

(

)

Rebuilds the entire index.

Returns

The result status.

Synchronize()

Status tkrzw::FileIndex::Synchronize

(

bool

hard

)

Synchronizes the content of the index to the file system.

Parameters

hard	True to do physical synchronization with the hardware or false to do only logical synchronization with the file system.

Returns

The result status.

IsOpen()

bool tkrzw::FileIndex::IsOpen

(

)

const

Checks whether the index is open.

Returns

True if the index is open, or false if not.

IsWritable()

bool tkrzw::FileIndex::IsWritable

(

)

const

Checks whether the index is writable.

Returns

True if the index is writable, or false if not.

GetInternalDBM()

TreeDBM * tkrzw::FileIndex::GetInternalDBM

(

)

const

Gets the pointer to the internal database object.

Returns

The pointer to the internal database object, or nullptr on failure.

MakeIterator()

std::unique_ptr< FileIndex::Iterator > tkrzw::FileIndex::MakeIterator

(

)

Makes an iterator for each record.

Returns

The iterator for each record.