mongo::StorageEngineMetadata Class Reference

This reads and write the storage engine metadata file 'storage.bson' in the data directory (See –dbpath). More...

#include <storage_engine_metadata.h>

Detailed Description

This reads and write the storage engine metadata file 'storage.bson' in the data directory (See –dbpath).

'storage.engine' is the only mandatory field in the BSON metadata file. Fields other than 'storage.engine' are ignored.

Public Member Functions
	StorageEngineMetadata (const std::string &dbpath)
	Sets fields to defaults. More...
virtual	~StorageEngineMetadata ()
const std::string &	getStorageEngine () const
	Returns name of storage engine in metadata. More...
const BSONObj &	getStorageEngineOptions () const
	Returns storage engine options in metadata. More...
void	setStorageEngine (const std::string &storageEngine)
	Sets name of storage engine in metadata. More...
void	setStorageEngineOptions (const BSONObj &storageEngineOptions)
	Sets storage engine options in metadata. More...
void	reset ()
	Resets fields to default values. More...
Status	read ()
	Reads metadata from 'storage.bson' in 'dbpath' directory. More...
Status	write () const
	Writes metadata to file. More...
template<typename T >
Status	validateStorageEngineOption (StringData fieldName, T expectedValue, boost::optional< T > defaultValue=boost::none) const
	Validates a single field in the storage engine options. More...
template<>
Status	validateStorageEngineOption (StringData fieldName, bool expectedValue, boost::optional< bool > defaultValue) const

Static Public Member Functions
static std::unique_ptr< StorageEngineMetadata >	forPath (const std::string &dbpath)
	Returns a metadata object describing the storage engine that backs the data files contained in 'dbpath', and nullptr otherwise. More...
static boost::optional< std::string >	getStorageEngineForPath (const std::string &dbpath)
	Returns the name of the storage engine that backs the data files contained in 'dbpath', and none otherwise. More...

Private Member Functions
	MONGO_DISALLOW_COPYING (StorageEngineMetadata)

Private Attributes
std::string	_dbpath
std::string	_storageEngine
BSONObj	_storageEngineOptions

Constructor & Destructor Documentation

StorageEngineMetadata()

mongo::StorageEngineMetadata::StorageEngineMetadata

(

const std::string &

dbpath

)

Sets fields to defaults.

Use read() load metadata from file.

~StorageEngineMetadata()

mongo::StorageEngineMetadata::~StorageEngineMetadata ( )

virtual

Member Function Documentation

forPath()

std::unique_ptr< StorageEngineMetadata > mongo::StorageEngineMetadata::forPath ( const std::string &  dbpath )

static

Returns a metadata object describing the storage engine that backs the data files contained in 'dbpath', and nullptr otherwise.

getStorageEngine()

const std::string & mongo::StorageEngineMetadata::getStorageEngine

(

)

const

Returns name of storage engine in metadata.

getStorageEngineForPath()

boost::optional< std::string > mongo::StorageEngineMetadata::getStorageEngineForPath ( const std::string &  dbpath )

static

Returns the name of the storage engine that backs the data files contained in 'dbpath', and none otherwise.

getStorageEngineOptions()

const BSONObj & mongo::StorageEngineMetadata::getStorageEngineOptions

(

)

const

Returns storage engine options in metadata.

MONGO_DISALLOW_COPYING()

mongo::StorageEngineMetadata::MONGO_DISALLOW_COPYING ( StorageEngineMetadata  )

private

read()

Status mongo::StorageEngineMetadata::read

(

)

Reads metadata from 'storage.bson' in 'dbpath' directory.

reset()

void mongo::StorageEngineMetadata::reset

(

)

Resets fields to default values.

setStorageEngine()

void mongo::StorageEngineMetadata::setStorageEngine

(

const std::string &

storageEngine

)

Sets name of storage engine in metadata.

setStorageEngineOptions()

void mongo::StorageEngineMetadata::setStorageEngineOptions

(

const BSONObj &

storageEngineOptions

)

Sets storage engine options in metadata.

validateStorageEngineOption() [1/2]

template<typename T >

Status mongo::StorageEngineMetadata::validateStorageEngineOption	(	StringData	fieldName,
		T	expectedValue,
		boost::optional< T >	defaultValue = boost::none
	)		const

Validates a single field in the storage engine options.

Currently, only boolean fields are supported. If the 'fieldName' does not exist in the 'storage.bson' file and a 'defaultValue' is passed in, the 'expectedValue' must match the 'defaultValue'.

validateStorageEngineOption() [2/2]

template<>

Status mongo::StorageEngineMetadata::validateStorageEngineOption	(	StringData	fieldName,
		bool	expectedValue,
		boost::optional< bool >	defaultValue
	)		const

write()

Status mongo::StorageEngineMetadata::write

(

)

const

Writes metadata to file.

Member Data Documentation

_dbpath

std::string mongo::StorageEngineMetadata::_dbpath

private

_storageEngine

std::string mongo::StorageEngineMetadata::_storageEngine

private

_storageEngineOptions

BSONObj mongo::StorageEngineMetadata::_storageEngineOptions

private

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

• /home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/storage_engine_metadata.h
• /home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/storage_engine_metadata.cpp