On-memory database manager implementation based on B+ tree. More...

#include <tkrzw_dbm_baby.h>

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

Public Member Functions
	BabyDBM (KeyComparator key_comparator=LexicalKeyComparator)
	Default constructor. More...

	BabyDBM (std::unique_ptr< File > file, KeyComparator key_comparator=LexicalKeyComparator)
	Constructor with a file object. More...

virtual	~BabyDBM ()
	Destructor. More...

	BabyDBM (const BabyDBM &rhs)=delete
	Copy and assignment are disabled. More...

BabyDBM &	operator= (const BabyDBM &rhs)=delete

Status	Open (const std::string &path, bool writable, int32_t options=File::OPEN_DEFAULT) override
	Opens a database file. More...

Status	Close () override
	Closes the database file. More...

Status	Process (std::string_view key, RecordProcessor *proc, bool writable) override
	Processes a record with a processor. More...

Status	Append (std::string_view key, std::string_view value, std::string_view delim="") override
	Appends data at the end of a record of a key. More...

Status	ProcessEach (RecordProcessor *proc, bool writable) override
	Processes each and every record in the database with a processor. More...

Status	Count (int64_t *count) override
	Gets the number of records. More...

Status	GetFileSize (int64_t *size) override
	Gets the current file size of the database. More...

Status	GetFilePath (std::string *path) override
	Gets the path of the database file. More...

Status	Clear () override
	Removes all records. More...

Status	Rebuild () override
	Rebuilds the entire database. More...

Status	ShouldBeRebuilt (bool *tobe) override
	Checks whether the database should be rebuilt. More...

Status	Synchronize (bool hard, FileProcessor *proc=nullptr) override
	Synchronizes the content of the database to the file system. More...

std::vector< std::pair< std::string, std::string > >	Inspect () override
	Inspects the database. More...

bool	IsOpen () const override
	Checks whether the database is open. More...

bool	IsWritable () const override
	Checks whether the database is writable. More...

bool	IsHealthy () const override
	Checks whether the database condition is healthy. More...

bool	IsOrdered () const override
	Checks whether ordered operations are supported. More...

std::unique_ptr< DBM::Iterator >	MakeIterator () override
	Makes an iterator for each record. More...

std::unique_ptr< DBM >	MakeDBM () const override
	Makes a new DBM object of the same concrete class. More...

KeyComparator	GetKeyComparator () const
	Gets the comparator of record keys. More...

Public Member Functions inherited from tkrzw::DBM
virtual	~DBM ()=default
	Destructor. More...

virtual Status	Process (std::string_view key, RecordLambdaType rec_lambda, bool writable)
	Processes a record with a lambda function. More...

virtual Status	Get (std::string_view key, std::string *value=nullptr)
	Gets the value of a record of a key. More...

virtual std::string	GetSimple (std::string_view key, std::string_view default_value="")
	Gets the value of a record of a key, in a simple way. More...

virtual std::map< std::string, std::string >	GetMulti (const std::initializer_list< std::string > &keys)
	Gets the values of multiple records of keys. More...

virtual std::map< std::string, std::string >	GetMulti (const std::vector< std::string > &keys)
	Gets the values of multiple records of keys, with a vector. More...

virtual Status	Set (std::string_view key, std::string_view value, bool overwrite=true, std::string *old_value=nullptr)
	Sets a record of a key and a value. More...

virtual Status	SetMulti (const std::initializer_list< std::pair< std::string, std::string >> &records, bool overwrite=true)
	Sets multiple records. More...

virtual Status	SetMulti (const std::map< std::string, std::string > &records, bool overwrite=true)
	Sets multiple records, with a map of strings. More...

virtual Status	Remove (std::string_view key, std::string *old_value=nullptr)
	Removes a record of a key. More...

virtual Status	CompareExchange (std::string_view key, std::string_view expected, std::string_view desired, std::string *actual=nullptr)
	Compares the value of a record and exchanges if the condition meets. More...

virtual Status	Increment (std::string_view key, int64_t increment=1, int64_t *current=nullptr, int64_t initial=0)
	Increments the numeric value of a record. More...

int64_t	IncrementSimple (std::string_view key, int64_t increment=1, int64_t initial=0)
	Increments the numeric value of a record, in a simple way. More...

virtual Status	ProcessEach (RecordLambdaType rec_lambda, bool writable)
	Processes each and every record in the database with a lambda function. More...

virtual int64_t	CountSimple ()
	Gets the number of records, in a simple way. More...

virtual int64_t	GetFileSizeSimple ()
	Gets the current file size of the database, in a simple way. More...

virtual std::string	GetFilePathSimple ()
	Gets the path of the database file, in a simple way. More...

virtual bool	ShouldBeRebuiltSimple ()
	Checks whether the database should be rebuilt, in a simple way. More...

virtual Status	CopyFile (const std::string &dest_path)
	Copies the content of the database file to another file. More...

virtual Status	Export (DBM *dbm)
	Exports all records to another database. More...

Additional Inherited Members
Public Types inherited from tkrzw::DBM
typedef std::function< std::string_view(std::string_view, std::string_view)>	RecordLambdaType
	Lambda function type to process a record. More...

Detailed Description

On-memory database manager implementation based on B+ tree.

All operations are thread-safe; Multiple threads can access the same database concurrently.

Constructor & Destructor Documentation

◆ BabyDBM() [1/3]

tkrzw::BabyDBM::BabyDBM ( KeyComparator key_comparator = LexicalKeyComparator )

Default constructor.

Parameters

key_comparator The comparator of record keys.

◆ BabyDBM() [2/3]

tkrzw::BabyDBM::BabyDBM	(	std::unique_ptr< File >	file,
		KeyComparator	key_comparator = `LexicalKeyComparator`
	)

Constructor with a file object.

Parameters

file	The file object to handle the data. The ownership is taken.
key_comparator	The comparator of record keys.

◆ ~BabyDBM()

virtual tkrzw::BabyDBM::~BabyDBM ( )

virtual

Destructor.

◆ BabyDBM() [3/3]

tkrzw::BabyDBM::BabyDBM ( const BabyDBM & rhs )

explicitdelete

Copy and assignment are disabled.

Member Function Documentation

◆ Open()

Status tkrzw::BabyDBM::Open	(	const std::string &	path,
		bool	writable,
		int32_t	options = `File::OPEN_DEFAULT`
	)

overridevirtual

Opens a database 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.

Returns: The result status.

As this database is an on-memory database, you can set records and retrieve them without opening a file. If you open a file, records are loaded from the file.

Implements tkrzw::DBM.

◆ Close()

Status tkrzw::BabyDBM::Close ( )

overridevirtual

Closes the database file.

Returns: The result status.

If a file is opened as writable, records are saved in the file.

Implements tkrzw::DBM.

◆ Process()

Status tkrzw::BabyDBM::Process	(	std::string_view	key,
		RecordProcessor *	proc,
		bool	writable
	)

overridevirtual

Processes a record with a processor.

Parameters

key	The key of the record.
proc	The pointer to the processor object.
writable	True if the processor can edit the record.

Returns: The result status.

If the specified record exists, the ProcessFull of the processor is called. Otherwise, the ProcessEmpty of the processor is called.

Implements tkrzw::DBM.

◆ Append()

Status tkrzw::BabyDBM::Append	(	std::string_view	key,
		std::string_view	value,
		std::string_view	delim = `""`
	)

overridevirtual

Appends data at the end of a record of a key.

Parameters

key	The key of the record.
value	The value to append.
delim	The delimiter to put after the existing record.

Returns: The result status.

If there's no existing record, the value is set without the delimiter.

Reimplemented from tkrzw::DBM.

◆ ProcessEach()

Status tkrzw::BabyDBM::ProcessEach	(	RecordProcessor *	proc,
		bool	writable
	)

overridevirtual

Processes each and every record in the database with a processor.

Parameters

proc	The pointer to the processor object.
writable	True if the processor can edit the record.

Returns: The result status.

The ProcessFull of the processor is called repeatedly for each record. The ProcessEmpty of the processor is called once before the iteration and once after the iteration.

Implements tkrzw::DBM.

◆ Count()

Status tkrzw::BabyDBM::Count ( int64_t * count )

overridevirtual

Gets the number of records.

Parameters

count The pointer to an integer object to contain the result count.

Returns: The result status.

Implements tkrzw::DBM.

◆ GetFileSize()

Status tkrzw::BabyDBM::GetFileSize ( int64_t * size )

overridevirtual

Gets the current file size of the database.

Parameters

size	The pointer to an integer object to contain the result size.

Returns: The result status.

Implements tkrzw::DBM.

◆ GetFilePath()

Status tkrzw::BabyDBM::GetFilePath ( std::string * path )

overridevirtual

Gets the path of the database file.

Parameters

path	The pointer to a string object to contain the result path.

Returns: The result status.

Implements tkrzw::DBM.

◆ Clear()

Status tkrzw::BabyDBM::Clear ( )

overridevirtual

Removes all records.

Returns: The result status.

Implements tkrzw::DBM.

◆ Rebuild()

Status tkrzw::BabyDBM::Rebuild ( )

overridevirtual

Rebuilds the entire database.

Returns: The result status.

This method does nothing.

Implements tkrzw::DBM.

◆ ShouldBeRebuilt()

Status tkrzw::BabyDBM::ShouldBeRebuilt ( bool * tobe )

overridevirtual

Checks whether the database should be rebuilt.

Parameters

tobe	The pointer to a boolean object to contain the result decision.

Returns: The result status.

There's no need for the database to be rebuilt.

Implements tkrzw::DBM.

◆ Synchronize()

Status tkrzw::BabyDBM::Synchronize	(	bool	hard,
		FileProcessor *	proc = `nullptr`
	)

overridevirtual

Synchronizes the content of the database 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.
proc	The pointer to the file processor object, whose Process method is called while the content of the file is synchronized. If it is nullptr, it is ignored.

Returns: The result status.

If a file is opened as writable, records are saved in the file.

Implements tkrzw::DBM.

◆ Inspect()

std::vector<std::pair<std::string, std::string> > tkrzw::BabyDBM::Inspect ( )

overridevirtual

Inspects the database.

Returns: A vector of pairs of a property name and its value.

Implements tkrzw::DBM.

◆ IsOpen()

bool tkrzw::BabyDBM::IsOpen ( ) const

overridevirtual

Checks whether the database is open.

Returns: True if the database is open, or false if not.

Implements tkrzw::DBM.

◆ IsWritable()

bool tkrzw::BabyDBM::IsWritable ( ) const

overridevirtual

Checks whether the database is writable.

Returns: True if the database is writable, or false if not.

Implements tkrzw::DBM.

◆ IsHealthy()

bool tkrzw::BabyDBM::IsHealthy ( ) const

overridevirtual

Checks whether the database condition is healthy.

Returns: Always true. On-memory databases never cause system errors.

Implements tkrzw::DBM.

◆ IsOrdered()

bool tkrzw::BabyDBM::IsOrdered ( ) const

overridevirtual

Checks whether ordered operations are supported.

Returns: Always true. Ordered operations are supported.

Implements tkrzw::DBM.

◆ MakeIterator()

std::unique_ptr<DBM::Iterator> tkrzw::BabyDBM::MakeIterator ( )

overridevirtual

Makes an iterator for each record.

Returns: The iterator for each record.

Implements tkrzw::DBM.

◆ MakeDBM()

std::unique_ptr<DBM> tkrzw::BabyDBM::MakeDBM ( ) const

overridevirtual

Makes a new DBM object of the same concrete class.

Returns: The new file object.

Implements tkrzw::DBM.

◆ GetKeyComparator()

KeyComparator tkrzw::BabyDBM::GetKeyComparator ( ) const

Gets the comparator of record keys.

Returns: the key comparator function, or nullptr on failure.

Classes

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BabyDBM() [1/3]

◆ BabyDBM() [2/3]

◆ ~BabyDBM()

◆ BabyDBM() [3/3]

Member Function Documentation

◆ Open()

◆ Close()

◆ Process()

◆ Append()

◆ ProcessEach()

◆ Count()

◆ GetFileSize()

◆ GetFilePath()

◆ Clear()

◆ Rebuild()

◆ ShouldBeRebuilt()

◆ Synchronize()

◆ Inspect()

◆ IsOpen()

◆ IsWritable()

◆ IsHealthy()

◆ IsOrdered()

◆ MakeIterator()

◆ MakeDBM()

◆ GetKeyComparator()