Interface of database manager. More...

#include <tkrzw_dbm.h>

Classes
class	FileProcessor
	Interface of processor for a record. More...

class	FileProcessorCopyFileData
	File processor to implement DBM::CopyFileData. More...

class	Iterator
	Interface of iterator for each record. More...

class	RecordCheckerCompareExchangeMulti
	Record checker to implement DBM::CompareExchangeMulti. More...

class	RecordCheckerRekey
	Record checker to implement DBM::Rekey. More...

class	RecordProcessor
	Interface of processor for a record. More...

class	RecordProcessorAppend
	Record processor to implement DBM::Append. More...

class	RecordProcessorCompareExchange
	Record processor to implement DBM::CompareExchange. More...

class	RecordProcessorExport
	Record processor to implement DBM::Export. More...

class	RecordProcessorGet
	Record processor to implement DBM::Get. More...

class	RecordProcessorIncrement
	Record processor to implement DBM::Increment. More...

class	RecordProcessorIterator
	Record processor to implement DBM::Iterator methods. More...

class	RecordProcessorLambda
	Record processor to implement DBM::Process with a lambda function. More...

class	RecordProcessorPopFirst
	Record processor to implement DBM::PopFirst. More...

class	RecordProcessorRemove
	Record processor to implement DBM::Remove. More...

class	RecordProcessorSet
	Record processor to implement DBM::Set. More...

class	RecordRemoverRekey
	Record remover to implement DBM::Rekey. More...

class	RecordSetterCompareExchangeMulti
	Record setter to implement DBM::CompareExchangeMulti. More...

class	RecordSetterRekey
	Record setter to implement DBM::Rekey. More...

class	UpdateLogger
	Interface of update logger. More...

Public Types
typedef std::function< std::string_view(std::string_view, std::string_view)>	RecordLambdaType
	Lambda function type to process a record. More...

Public Member Functions
virtual	~DBM ()=default
	Destructor. More...

virtual Status	Open (const std::string &path, bool writable, int32_t options=File::OPEN_DEFAULT)=0
	Opens a database file. More...

virtual Status	Close ()=0
	Closes the database file. More...

virtual Status	Process (std::string_view key, RecordProcessor *proc, bool writable)=0
	Processes a record with a processor. 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 Status	GetMulti (const std::vector< std::string_view > &keys, std::map< std::string, std::string > *records)
	Gets the values of multiple records of keys, with a string view vector. More...

virtual Status	GetMulti (const std::initializer_list< std::string_view > &keys, std::map< std::string, std::string > *records)
	Gets the values of multiple records of keys, with an initializer list. More...

virtual Status	GetMulti (const std::vector< std::string > &keys, std::map< std::string, std::string > *records)
	Gets the values of multiple records of keys, with a string 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::map< std::string_view, std::string_view > &records, bool overwrite=true)
	Sets multiple records, with a map of string views. More...

virtual Status	SetMulti (const std::initializer_list< std::pair< std::string_view, std::string_view >> &records, bool overwrite=true)
	Sets multiple records, with an initializer list. 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	RemoveMulti (const std::vector< std::string_view > &keys)
	Removes records of keys, with a string view vector. More...

virtual Status	RemoveMulti (const std::initializer_list< std::string_view > &keys)
	Removes records of keys, with an initializer list. More...

virtual Status	RemoveMulti (const std::vector< std::string > &keys)
	Removes records of keys, with a string vector. More...

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

virtual Status	AppendMulti (const std::map< std::string_view, std::string_view > &records, std::string_view delim="")
	Appends data to multiple records, with a map of string views. More...

virtual Status	AppendMulti (const std::initializer_list< std::pair< std::string_view, std::string_view >> &records, std::string_view delim="")
	Appends data to multiple records, with an initializer list. More...

virtual Status	AppendMulti (const std::map< std::string, std::string > &records, std::string_view delim="")
	Appends data to multiple records, with a map of strings. More...

virtual Status	CompareExchange (std::string_view key, std::string_view expected, std::string_view desired, std::string actual=nullptr, bool found=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...

virtual 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	ProcessMulti (const std::vector< std::pair< std::string_view, RecordProcessor * >> &key_proc_pairs, bool writable)=0
	Processes multiple records with processors. More...

virtual Status	ProcessMulti (const std::vector< std::pair< std::string_view, RecordLambdaType >> &key_lambda_pairs, bool writable)
	Processes multiple records with lambda functions. More...

virtual Status	CompareExchangeMulti (const std::vector< std::pair< std::string_view, std::string_view >> &expected, const std::vector< std::pair< std::string_view, std::string_view >> &desired)
	Compares the values of records and exchanges if the condition meets. More...

virtual Status	Rekey (std::string_view old_key, std::string_view new_key, bool overwrite=true, bool copying=false, std::string *value=nullptr)
	Changes the key of a record. More...

virtual Status	ProcessFirst (RecordProcessor *proc, bool writable)=0
	Processes the first record with a processor. More...

virtual Status	ProcessFirst (RecordLambdaType rec_lambda, bool writable)
	Processes the first record with a lambda function. More...

virtual Status	PopFirst (std::string key=nullptr, std::string value=nullptr)
	Gets the first record and removes it. More...

virtual Status	PushLast (std::string_view value, double wtime=-1, std::string *key=nullptr)
	Adds a record with a key of the current timestamp. More...

virtual Status	ProcessEach (RecordProcessor *proc, bool writable)=0
	Processes each and every record in the database with a processor. More...

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

virtual Status	Count (int64_t *count)=0
	Gets the number of records. More...

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

virtual Status	GetFileSize (int64_t *size)=0
	Gets the current file size of the database. More...

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

virtual Status	GetFilePath (std::string *path)=0
	Gets the path of the database file. More...

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

virtual Status	GetTimestamp (double *timestamp)=0
	Gets the timestamp in seconds of the last modified time. More...

virtual double	GetTimestampSimple ()
	Gets the timestamp of the last modified time, in a simple way. More...

virtual Status	Clear ()=0
	Removes all records. More...

virtual Status	Rebuild ()=0
	Rebuilds the entire database. More...

virtual Status	ShouldBeRebuilt (bool *tobe)=0
	Checks whether the database should be rebuilt. More...

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

virtual Status	Synchronize (bool hard, FileProcessor *proc=nullptr)=0
	Synchronizes the content of the database to the file system. More...

virtual Status	CopyFileData (const std::string &dest_path, bool sync_hard=false)
	Copies the content of the database file to another file. More...

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

virtual std::vector< std::pair< std::string, std::string > >	Inspect ()=0
	Inspects the database. More...

virtual bool	IsOpen () const =0
	Checks whether the database is open. More...

virtual bool	IsWritable () const =0
	Checks whether the database is writable. More...

virtual bool	IsHealthy () const =0
	Checks whether the database condition is healthy. More...

virtual bool	IsOrdered () const =0
	Checks whether ordered operations are supported. More...

virtual std::unique_ptr< Iterator >	MakeIterator ()=0
	Makes an iterator for each record. More...

virtual std::unique_ptr< DBM >	MakeDBM () const =0
	Makes a new DBM object of the same concrete class. More...

virtual UpdateLogger *	GetUpdateLogger () const =0
	Gets the logger to write all update operations. More...

virtual void	SetUpdateLogger (UpdateLogger *update_logger)=0
	Sets the logger to write all update operations. More...

const std::type_info &	GetType () const
	Gets the type information of the actual class. More...

Static Public Attributes
static const std::string_view	ANY_DATA
	The special string_view value to represent any data. More...

Detailed Description

Interface of database manager.

Member Typedef Documentation

◆ RecordLambdaType

typedef std::function<std::string_view(std::string_view, std::string_view)> tkrzw::DBM::RecordLambdaType

Lambda function type to process a record.

The first parameter is the key of the record. The second parameter is the value of the existing record, or NOOP if it the record doesn't exist. The return value is a string reference to NOOP, REMOVE, or the new record value.

Constructor & Destructor Documentation

◆ ~DBM()

virtual tkrzw::DBM::~DBM ( )

virtualdefault

Destructor.

Member Function Documentation

◆ Open()

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

pure virtual

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 of File::OpenOption enums for opening the file.

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ Close()

virtual Status tkrzw::DBM::Close ( )

pure virtual

Closes the database file.

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ Process() [1/2]

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

pure virtual

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.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ Process() [2/2]

virtual Status tkrzw::DBM::Process	(	std::string_view	key,
		RecordLambdaType	rec_lambda,
		bool	writable
	)

virtual

Processes a record with a lambda function.

Parameters

key	The key of the record.
rec_lambda	The lambda function to process a record. The first parameter is the key of the record. The second parameter is the value of the existing record, or RecordProcessor::NOOP if it the record doesn't exist. The return value is a string reference to RecordProcessor::NOOP, RecordProcessor::REMOVE, or the new record value.
writable	True if the processor can edit the record.

Returns: The result status.

◆ Get()

virtual Status tkrzw::DBM::Get	(	std::string_view	key,
		std::string *	value = `nullptr`
	)

virtual

Gets the value of a record of a key.

Parameters

key	The key of the record.
value	The pointer to a string object to contain the result value. If it is nullptr, the value data is ignored.

Returns: The result status. If there's no matching record, NOT_FOUND_ERROR is returned.

Reimplemented in tkrzw::ShardDBM, tkrzw::PolyDBM, and tkrzw::HashDBM.

◆ GetSimple()

virtual std::string tkrzw::DBM::GetSimple	(	std::string_view	key,
		std::string_view	default_value = `""`
	)

virtual

Gets the value of a record of a key, in a simple way.

Parameters

key	The key of the record.
default_value	The value to be returned on failure.

Returns: The value of the matching record on success, or the default value on failure.

◆ GetMulti() [1/3]

virtual Status tkrzw::DBM::GetMulti	(	const std::vector< std::string_view > &	keys,
		std::map< std::string, std::string > *	records
	)

virtual

Gets the values of multiple records of keys, with a string view vector.

Parameters

keys	The keys of records to retrieve.
records	The pointer to a map to store retrieved records. Keys which don't match existing records are ignored.

Returns: The result status. If all records of the given keys are found, SUCCESS is returned. If one or more records are missing, NOT_FOUND_ERROR is returned. Thus, even with an error code, the result map can have elements.

◆ GetMulti() [2/3]

virtual Status tkrzw::DBM::GetMulti	(	const std::initializer_list< std::string_view > &	keys,
		std::map< std::string, std::string > *	records
	)

virtual

Gets the values of multiple records of keys, with an initializer list.

Parameters

keys	The keys of records to retrieve.
records	The pointer to a map to store retrieved records. Keys which don't match existing records are ignored.

Returns: The result status. If all records of the given keys are found, SUCCESS is returned. If one or more records are missing, NOT_FOUND_ERROR is returned. Thus, even with an error code, the result map can have elements.

◆ GetMulti() [3/3]

virtual Status tkrzw::DBM::GetMulti	(	const std::vector< std::string > &	keys,
		std::map< std::string, std::string > *	records
	)

virtual

Gets the values of multiple records of keys, with a string vector.

Parameters

keys	The keys of records to retrieve.
records	The pointer to a map to store retrieved records. Keys which don't match existing records are ignored.

Returns: The result status. If all records of the given keys are found, SUCCESS is returned. If one or more records are missing, NOT_FOUND_ERROR is returned. Thus, even with an error code, the result map can have elements.

◆ Set()

virtual Status tkrzw::DBM::Set	(	std::string_view	key,
		std::string_view	value,
		bool	overwrite = `true`,
		std::string *	old_value = `nullptr`
	)

virtual

Sets a record of a key and a value.

Parameters

key	The key of the record.
value	The value of the record.
overwrite	Whether to overwrite the existing value if there's a record with the same key. If true, the existing value is overwritten by the new value. If false, the operation is given up and an error status is returned.
old_value	The pointer to a string object to contain the old value. Assignment is done even on the duplication error. If it is nullptr, it is ignored.

Returns: The result status. If overwriting is abandoned, DUPLICATION_ERROR is returned.

Reimplemented in tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, and tkrzw::HashDBM.

◆ SetMulti() [1/3]

virtual Status tkrzw::DBM::SetMulti	(	const std::map< std::string_view, std::string_view > &	records,
		bool	overwrite = `true`
	)

virtual

Sets multiple records, with a map of string views.

Parameters

records	The records to store.
overwrite	Whether to overwrite the existing value if there's a record with the same key. If true, the existing value is overwritten by the new value. If false, the operation is given up and an error status is returned.

Returns: The result status. If there are records avoiding overwriting, DUPLICATION_ERROR is returned.

◆ SetMulti() [2/3]

virtual Status tkrzw::DBM::SetMulti	(	const std::initializer_list< std::pair< std::string_view, std::string_view >> &	records,
		bool	overwrite = `true`
	)

virtual

Sets multiple records, with an initializer list.

Parameters

records	The records to store.
overwrite	Whether to overwrite the existing value if there's a record with the same key. If true, the existing value is overwritten by the new value. If false, the operation is given up and an error status is returned.

Returns: The result status. If there are records avoiding overwriting, DUPLICATION_ERROR is returned.

◆ SetMulti() [3/3]

virtual Status tkrzw::DBM::SetMulti	(	const std::map< std::string, std::string > &	records,
		bool	overwrite = `true`
	)

virtual

Sets multiple records, with a map of strings.

Parameters

records	The records to store.
overwrite	Whether to overwrite the existing value if there's a record with the same key. If true, the existing value is overwritten by the new value. If false, the operation is given up and an error status is returned.

Returns: The result status. If there are records avoiding overwriting, DUPLICATION_ERROR is returned.

◆ Remove()

virtual Status tkrzw::DBM::Remove	(	std::string_view	key,
		std::string *	old_value = `nullptr`
	)

virtual

Removes a record of a key.

Parameters

key	The key of the record.
old_value	The pointer to a string object to contain the old value. If it is nullptr, it is ignored.

Returns: The result status. If there's no matching record, NOT_FOUND_ERROR is returned.

Reimplemented in tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, and tkrzw::HashDBM.

◆ RemoveMulti() [1/3]

virtual Status tkrzw::DBM::RemoveMulti ( const std::vector< std::string_view > & keys )

virtual

Removes records of keys, with a string view vector.

Parameters

keys	The keys of records to remove.

Returns: The result status. If there are missing records, NOT_FOUND_ERROR is returned.

◆ RemoveMulti() [2/3]

virtual Status tkrzw::DBM::RemoveMulti ( const std::initializer_list< std::string_view > & keys )

virtual

Removes records of keys, with an initializer list.

Parameters

keys	The keys of records to remove.

Returns: The result status.

◆ RemoveMulti() [3/3]

virtual Status tkrzw::DBM::RemoveMulti ( const std::vector< std::string > & keys )

virtual

Removes records of keys, with a string vector.

Parameters

keys	The keys of records to remove.

Returns: The result status. If there are missing records, NOT_FOUND_ERROR is returned.

◆ Append()

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

virtual

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 in tkrzw::TinyDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, and tkrzw::BabyDBM.

◆ AppendMulti() [1/3]

virtual Status tkrzw::DBM::AppendMulti	(	const std::map< std::string_view, std::string_view > &	records,
		std::string_view	delim = `""`
	)

virtual

Appends data to multiple records, with a map of string views.

Parameters

records	The records 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.

◆ AppendMulti() [2/3]

virtual Status tkrzw::DBM::AppendMulti	(	const std::initializer_list< std::pair< std::string_view, std::string_view >> &	records,
		std::string_view	delim = `""`
	)

virtual

Appends data to multiple records, with an initializer list.

Parameters

records	The records to store.
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.

◆ AppendMulti() [3/3]

virtual Status tkrzw::DBM::AppendMulti	(	const std::map< std::string, std::string > &	records,
		std::string_view	delim = `""`
	)

virtual

Appends data to multiple records, with a map of strings.

Parameters

records	The records 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.

◆ CompareExchange()

virtual Status tkrzw::DBM::CompareExchange	(	std::string_view	key,
		std::string_view	expected,
		std::string_view	desired,
		std::string *	actual = `nullptr`,
		bool *	found = `nullptr`
	)

virtual

Compares the value of a record and exchanges if the condition meets.

Parameters

key	The key of the record.
expected	The expected value. If the data is nullptr, no existing record is expected. If it is ANY_DATA, an existing record with any value is expacted.
desired	The desired value. If the data is nullptr, the record is to be removed. If it is ANY_DATA, no update is done.
actual	The pointer to a string object to contain the actual value of the existing record. If it is nullptr, it is ignored.
found	The pointer to a variable to contain whether there is an existing record. If it is nullptr, it is ignored.

Returns: The result status. If the condition doesn't meet, INFEASIBLE_ERROR is returned.

◆ Increment()

virtual Status tkrzw::DBM::Increment	(	std::string_view	key,
		int64_t	increment = `1`,
		int64_t *	current = `nullptr`,
		int64_t	initial = `0`
	)

virtual

Increments the numeric value of a record.

Parameters

key	The key of the record.
increment	The incremental value. If it is INT64MIN, the current value is not changed and a new record is not created.
current	The pointer to an integer to contain the current value. If it is nullptr, it is ignored.
initial	The initial value.

Returns: The result status.

The record value is stored as an 8-byte big-endian integer. Negative is also supported.

◆ IncrementSimple()

virtual int64_t tkrzw::DBM::IncrementSimple	(	std::string_view	key,
		int64_t	increment = `1`,
		int64_t	initial = `0`
	)

virtual

Increments the numeric value of a record, in a simple way.

Parameters

key	The key of the record.
increment	The incremental value.
initial	The initial value.

Returns: The current value or INT64MIN on failure.

The record value is treated as a decimal integer. Negative is also supported.

◆ ProcessMulti() [1/2]

virtual Status tkrzw::DBM::ProcessMulti	(	const std::vector< std::pair< std::string_view, RecordProcessor * >> &	key_proc_pairs,
		bool	writable
	)

pure virtual

Processes multiple records with processors.

Parameters

key_proc_pairs	Pairs of the keys and their processor objects.
writable	True if the processors can edit the records.

Returns: The result status.

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

◆ ProcessMulti() [2/2]

virtual Status tkrzw::DBM::ProcessMulti	(	const std::vector< std::pair< std::string_view, RecordLambdaType >> &	key_lambda_pairs,
		bool	writable
	)

virtual

Processes multiple records with lambda functions.

Parameters

key_lambda_pairs	Pairs of the keys and their lambda functions. The first parameter of the lambda functions is the key of the record, or RecordProcessor::NOOP if it the record doesn't exist. The return value is a string reference to RecordProcessor::NOOP, RecordProcessor::REMOVE, or the new record value.
writable	True if the processors can edit the records.

Returns: The result status.

◆ CompareExchangeMulti()

virtual Status tkrzw::DBM::CompareExchangeMulti	(	const std::vector< std::pair< std::string_view, std::string_view >> &	expected,
		const std::vector< std::pair< std::string_view, std::string_view >> &	desired
	)

virtual

Compares the values of records and exchanges if the condition meets.

Parameters

expected	The record keys and their expected values. If the value data is nullptr, no existing record is expected. If the value is ANY_DATA, an existing record with any value is expacted.
desired	The record keys and their desired values. If the value is nullptr, the record is to be removed.

Returns: The result status. If the condition doesn't meet, INFEASIBLE_ERROR is returned.

Reimplemented in tkrzw::ShardDBM.

◆ Rekey()

virtual Status tkrzw::DBM::Rekey	(	std::string_view	old_key,
		std::string_view	new_key,
		bool	overwrite = `true`,
		bool	copying = `false`,
		std::string *	value = `nullptr`
	)

virtual

Changes the key of a record.

Parameters

old_key	The old key of the record.
new_key	The new key of the record.
overwrite	Whether to overwrite the existing record of the new key.
copying	Whether to retain the record of the old key.
value	The pointer to a string object to contain the value of the record. If it is nullptr, the value data is ignored.

Returns: The result status. If there's no matching record to the old key, NOT_FOUND_ERROR is returned. If the overwrite flag is false and there is an existing record of the new key, DUPLICATION ERROR is returned.

This method is done atomically by ProcessMulti. The other threads observe that the record has either the old key or the new key. No intermediate states are observed.

◆ ProcessFirst() [1/2]

virtual Status tkrzw::DBM::ProcessFirst	(	RecordProcessor *	proc,
		bool	writable
	)

pure virtual

Processes the first record with a processor.

Parameters

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

Returns: The result status.

If the first record exists, the ProcessFull of the processor is called. Otherwise, this method fails and no method of the processor is called. Whereas ordered databases have efficient implementations of this method, unordered databases have inefficient implementations.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ ProcessFirst() [2/2]

virtual Status tkrzw::DBM::ProcessFirst	(	RecordLambdaType	rec_lambda,
		bool	writable
	)

virtual

Processes the first record with a lambda function.

Parameters

rec_lambda	The lambda function to process a record. The first parameter is the key of the record. The second parameter is the value of the record. The return value is a string reference to RecordProcessor::NOOP, RecordProcessor::REMOVE, or the new record value.
writable	True if the processor can edit the record.

Returns: The result status.

◆ PopFirst()

virtual Status tkrzw::DBM::PopFirst	(	std::string *	key = `nullptr`,
		std::string *	value = `nullptr`
	)

virtual

Gets the first record and removes it.

Parameters

key	The pointer to a string object to contain the key of the first record. If it is nullptr, it is ignored.
value	The pointer to a string object to contain the value of the first record. If it is nullptr, it is ignored.

Returns: The result status.

◆ PushLast()

virtual Status tkrzw::DBM::PushLast	(	std::string_view	value,
		double	wtime = `-1`,
		std::string *	key = `nullptr`
	)

virtual

Adds a record with a key of the current timestamp.

Parameters

value	The value of the record.
wtime	The current wall time used to generate the key. If it is negative, the system clock is used.
key	The pointer to a string object to contain the generated key of the record. If it is nullptr, it is ignored.

Returns: The result status.

The key is generated as an 8-bite big-endian binary string of the timestamp. If there is an existing record matching the generated key, the key is regenerated and the attempt is repeated until it succeeds.

◆ ProcessEach() [1/2]

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

pure virtual

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.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ ProcessEach() [2/2]

virtual Status tkrzw::DBM::ProcessEach	(	RecordLambdaType	rec_lambda,
		bool	writable
	)

virtual

Processes each and every record in the database with a lambda function.

Parameters

rec_lambda	The lambda function to process a record. The first parameter is the key of the record. The second parameter is the value of the existing record, or RecordProcessor::NOOP if it the record doesn't exist. The return value is a string reference to RecordProcessor::NOOP, RecordProcessor::REMOVE, or the new record value.
writable	True if the processor can edit the record.

Returns: The result status.

The lambda function is called repeatedly for each record. It is also called once before the iteration and once after the iteration with both the key and the value being RecordProcessor::NOOP.

◆ Count()

virtual Status tkrzw::DBM::Count ( int64_t * count )

pure virtual

Gets the number of records.

Parameters

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

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ CountSimple()

virtual int64_t tkrzw::DBM::CountSimple ( )

virtual

Gets the number of records, in a simple way.

Returns: The number of records on success, or -1 on failure.

◆ GetFileSize()

virtual Status tkrzw::DBM::GetFileSize ( int64_t * size )

pure virtual

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.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ GetFileSizeSimple()

virtual int64_t tkrzw::DBM::GetFileSizeSimple ( )

virtual

Gets the current file size of the database, in a simple way.

Returns: The current file size of the database, or -1 on failure.

◆ GetFilePath()

virtual Status tkrzw::DBM::GetFilePath ( std::string * path )

pure virtual

Gets the path of the database file.

Parameters

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

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ GetFilePathSimple()

virtual std::string tkrzw::DBM::GetFilePathSimple ( )

virtual

Gets the path of the database file, in a simple way.

Returns: The file path of the database, or an empty string on failure.

◆ GetTimestamp()

virtual Status tkrzw::DBM::GetTimestamp ( double * timestamp )

pure virtual

Gets the timestamp in seconds of the last modified time.

Parameters

timestamp The pointer to a double object to contain the timestamp.

Returns: The result status.

The timestamp is updated when the database opened in the writable mode is closed or synchronized, even if no updating opertion is done.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ GetTimestampSimple()

virtual double tkrzw::DBM::GetTimestampSimple ( )

virtual

Gets the timestamp of the last modified time, in a simple way.

Returns: The timestamp of the last modified time, or NaN on failure.

◆ Clear()

virtual Status tkrzw::DBM::Clear ( )

pure virtual

Removes all records.

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ Rebuild()

virtual Status tkrzw::DBM::Rebuild ( )

pure virtual

Rebuilds the entire database.

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ ShouldBeRebuilt()

virtual Status tkrzw::DBM::ShouldBeRebuilt ( bool * tobe )

pure virtual

Checks whether the database should be rebuilt.

Parameters

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

Returns: The result status.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ ShouldBeRebuiltSimple()

virtual bool tkrzw::DBM::ShouldBeRebuiltSimple ( )

virtual

Checks whether the database should be rebuilt, in a simple way.

Returns: True if the database should be rebuilt or false if not or on failure.

◆ Synchronize()

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

pure virtual

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.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ CopyFileData()

virtual Status tkrzw::DBM::CopyFileData	(	const std::string &	dest_path,
		bool	sync_hard = `false`
	)

virtual

Copies the content of the database file to another file.

Parameters

dest_path	A path to the destination file.
sync_hard	True to do physical synchronization with the hardware.

Returns: The result status.

Copying is done while the content is synchronized and stable. So, this method is suitable for making a backup file while running a database service.

Reimplemented in tkrzw::ShardDBM.

◆ Export()

virtual Status tkrzw::DBM::Export ( DBM * dest_dbm )

virtual

Exports all records to another database.

Parameters

dest_dbm The pointer to the destination database.

Returns: The result status.

◆ Inspect()

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

pure virtual

Inspects the database.

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

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ IsOpen()

virtual bool tkrzw::DBM::IsOpen ( ) const

pure virtual

Checks whether the database is open.

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

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ IsWritable()

virtual bool tkrzw::DBM::IsWritable ( ) const

pure virtual

Checks whether the database is writable.

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

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ IsHealthy()

virtual bool tkrzw::DBM::IsHealthy ( ) const

pure virtual

Checks whether the database condition is healthy.

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

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ IsOrdered()

virtual bool tkrzw::DBM::IsOrdered ( ) const

pure virtual

Checks whether ordered operations are supported.

Returns: True if ordered operations are supported, or false if not.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ MakeIterator()

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

pure virtual

Makes an iterator for each record.

Returns: The iterator for each record.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ MakeDBM()

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

pure virtual

Makes a new DBM object of the same concrete class.

Returns: The new DBM object.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ GetUpdateLogger()

virtual UpdateLogger* tkrzw::DBM::GetUpdateLogger ( ) const

pure virtual

Gets the logger to write all update operations.

Returns: The update logger if it has been set or nullptr if it hasn't.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ SetUpdateLogger()

virtual void tkrzw::DBM::SetUpdateLogger ( UpdateLogger * update_logger )

pure virtual

Sets the logger to write all update operations.

Parameters

update_logger The pointer to the update logger object. Ownership is not taken. If it is nullptr, no logger is used.

Implemented in tkrzw::TreeDBM, tkrzw::TinyDBM, tkrzw::StdTreeDBM, tkrzw::StdHashDBM, tkrzw::SkipDBM, tkrzw::ShardDBM, tkrzw::PolyDBM, tkrzw::HashDBM, tkrzw::CacheDBM, and tkrzw::BabyDBM.

◆ GetType()

const std::type_info& tkrzw::DBM::GetType ( ) const

Gets the type information of the actual class.

Returns: The type information of the actual class.

Member Data Documentation

◆ ANY_DATA

const std::string_view tkrzw::DBM::ANY_DATA

static

The special string_view value to represent any data.

Classes

Public Types

Public Member Functions

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ RecordLambdaType

Constructor & Destructor Documentation

◆ ~DBM()

Member Function Documentation

◆ Open()

◆ Close()

◆ Process() [1/2]

◆ Process() [2/2]

◆ Get()

◆ GetSimple()

◆ GetMulti() [1/3]

◆ GetMulti() [2/3]

◆ GetMulti() [3/3]

◆ Set()

◆ SetMulti() [1/3]

◆ SetMulti() [2/3]

◆ SetMulti() [3/3]

◆ Remove()

◆ RemoveMulti() [1/3]

◆ RemoveMulti() [2/3]

◆ RemoveMulti() [3/3]

◆ Append()

◆ AppendMulti() [1/3]

◆ AppendMulti() [2/3]

◆ AppendMulti() [3/3]

◆ CompareExchange()

◆ Increment()

◆ IncrementSimple()

◆ ProcessMulti() [1/2]

◆ ProcessMulti() [2/2]

◆ CompareExchangeMulti()

◆ Rekey()

◆ ProcessFirst() [1/2]

◆ ProcessFirst() [2/2]

◆ PopFirst()

◆ PushLast()

◆ ProcessEach() [1/2]

◆ ProcessEach() [2/2]

◆ Count()

◆ CountSimple()

◆ GetFileSize()

◆ GetFileSizeSimple()

◆ GetFilePath()

◆ GetFilePathSimple()

◆ GetTimestamp()

◆ GetTimestampSimple()

◆ Clear()

◆ Rebuild()

◆ ShouldBeRebuilt()

◆ ShouldBeRebuiltSimple()

◆ Synchronize()

◆ CopyFileData()

◆ Export()

◆ Inspect()

◆ IsOpen()

◆ IsWritable()

◆ IsHealthy()

◆ IsOrdered()

◆ MakeIterator()

◆ MakeDBM()

◆ GetUpdateLogger()

◆ SetUpdateLogger()

◆ GetType()

Member Data Documentation

◆ ANY_DATA