C++ representation of a "BSON" object – that is, an extended JSON-style object in a binary representation. More...

#include <bsonobj.h>

Inheritance diagram for bson::BSONObj:

Classes
class	Holder

Public Types
enum	MatchType { Equality = 0, LT = 0x1, LTE = 0x3, GTE = 0x6, GT = 0x4, opIN = 0x8, NE = 0x9, opSIZE = 0x0A, opALL = 0x0B, NIN = 0x0C, opEXISTS = 0x0D, opMOD = 0x0E, opTYPE = 0x0F, opREGEX = 0x10, opOPTIONS = 0x11, opELEM_MATCH = 0x12, opNEAR = 0x13, opWITHIN = 0x14, opMAX_DISTANCE =0x15, opISNULL =0x16 }

typedef bson_intrusive_ptr < Holder, TrivialAllocator >	holder_type

typedef BSONObjIterator	iterator

Public Member Functions
	BSONObj (const char *msgdata, bool check=true)
	Construct a BSONObj from data in the proper format.

	BSONObj (holder_type holder)
	Construct a BSONObj from data in the proper format.

	BSONObj ()
	Construct an empty BSONObj – that is, {}.

bool	isOwned () const
	A BSONObj can use a buffer it "owns" or one it does not.

BSONObj	getOwned () const
	assure the data buffer is under the control of this BSONObj and not a remote buffer

BSONObj	copy () const

string	toString (bool isArray=false, bool full=false, bool noThrow=true) const
	Readable representation of a BSON object in an extended JSON-style notation.

void	toString (StringBuilder &s, bool isArray=false, bool full=false) const

string	jsonString (JsonStringFormat format=Strict, int pretty=0) const
	Properly formatted JSON string.

int	addFields (BSONObj &from, set< string > &fields)
	note: addFields always adds _id even if not specified

int	nFields () const
	returns # of top level fields in the object note: iterates to count the fields

int	getFieldNames (set< string > &fields) const
	adds the field names to the fields set.

BSONElement	getFieldDotted (const char *name) const

BSONElement	getFieldDotted (const string &name) const

void	getFieldsDotted (const StringData &name, BSONElementSet &ret) const
	Like getFieldDotted(), but expands arrays and returns all matching objects.

void	getFieldsDotted (const StringData &name, BSONElementMSet &ret) const

BSONElement	getFieldDottedOrArray (const char *&name) const
	Like getFieldDotted(), but returns first array encountered while traversing the dotted fields of name.

BSONElement	getField (const StringData &name) const
	Get the field of the specified name.

BSONElement	getField (const char *name) const

void	getFields (unsigned n, const char *fieldNames, BSONElement fields) const
	Get several fields at once.

BSONElement	operator[] (const char *field) const
	Get the field of the specified name.

BSONElement	operator[] (const string &field) const

BSONElement	operator[] (int field) const

bool	hasField (const char *name) const

bool	hasElement (const char *name) const

const char *	getStringField (const char *name) const

BSONObj	getObjectField (const char *name) const

int	getIntField (const char *name) const

bool	getBoolField (const char *name) const

BSONObj	extractFieldsUnDotted (BSONObj pattern) const
	sets element field names to empty string If a field in pattern is missing, it is omitted from the returned object.

BSONObj	extractFields (const BSONObj &pattern, bool fillWithNull=false) const
	extract items from object which match a pattern object.

BSONObj	filterFieldsUndotted (const BSONObj &filter, bool inFilter) const

BSONElement	getFieldUsingIndexNames (const char *fieldName, const BSONObj &indexKey) const

const char *	objdata () const

int	objsize () const

bool	isValid () const
	performs a cursory check on the object's size only.

bool	okForStorage () const

bool	isEmpty () const

void	dump () const

string	hexDump () const
	Alternative output format.

int	woCompare (const BSONObj &r, const Ordering &o, bool considerFieldName=true) const
	wo='well ordered'.

int	woCompare (const BSONObj &r, const BSONObj &ordering=BSONObj(), bool considerFieldName=true) const
	wo='well ordered'.

bool	operator< (const BSONObj &other) const

bool	operator<= (const BSONObj &other) const

bool	operator> (const BSONObj &other) const

bool	operator>= (const BSONObj &other) const

int	woSortOrder (const BSONObj &r, const BSONObj &sortKey, bool useDotted=false) const

bool	equal (const BSONObj &r) const

bool	shallowEqual (const BSONObj &r) const
	This is "shallow equality" – ints and doubles won't match.

BSONElement	firstElement () const

const char *	firstElementFieldName () const
	faster than firstElement().fieldName() - for the first element we can easily find the fieldname without computing the element size.

bool	getObjectID (BSONElement &e) const
	Get the _id field from the object.

int	hash () const

BSONObj	clientReadable () const

BSONObj	replaceFieldNames (const BSONObj &obj) const
	Return new object with the field names replaced by those in the passed object.

bool	valid () const
	true unless corrupt

string	md5 () const

bool	operator== (const BSONObj &other) const

void	elems (vector< BSONElement > &) const
	add all elements of the object to the specified vector

void	elems (list< BSONElement > &) const
	add all elements of the object to the specified list

template<class T >
void	Vals (vector< T > &) const
	add all values of the object to the specified vector.

template<class T >
void	Vals (list< T > &) const
	add all values of the object to the specified list.

template<class T >
void	vals (vector< T > &) const
	add all values of the object to the specified vector.

template<class T >
void	vals (list< T > &) const
	add all values of the object to the specified list.

BSONObjIterator	begin () const
	use something like this: for( BSONObj::iterator i = myObj.begin(); i.more(); ) { BSONElement e = i.next(); ...

void	appendSelfToBufBuilder (BufBuilder &b) const

void	init (const char *data, bool check=true)
	initialize from existing buffer

Static Public Member Functions
static void	setJSCompatibility (bool compatible)
	when this value is not zero, the BSONObje::toString() method will show the string which is the same with that shows in sdb shell.

static bool	getJSCompatibility ()
	get whether bson_print method will show the string which is the same with that shows in sdb shell or not

Friends
class	BSONObjIterator

Detailed Description

C++ representation of a "BSON" object – that is, an extended JSON-style object in a binary representation.

See bsonspec.org.

Note that BSONObj's have a smart pointer capability built in – so you can pass them around by value. The reference counts used to implement this do not use locking, so copying and destroying BSONObj's are not thread-safe operations.

BSON object format:

code <unsigned totalsize>=""> {<byte bsontype>=""><cstring fieldname>=""><Data>}* EOO

totalSize includes itself.

Data: Bool: <byte> EOO: nothing follows Undefined: nothing follows OID: an OID object NumberDouble: <double> NumberInt: <int32> String: <unsigned32 strsizewithnull>=""><cstring> Date: <8bytes> Regex: <cstring regex>=""><cstring options>=""> Object: a nested object, leading with its entire size, which terminates with EOO. Array: same as object DBRef: <strlen> <cstring ns>=""> <oid> DBRef: a database reference: basically a collection name plus an Object ID BinData: <int len>=""> <byte subtype>=""> <byte[len] data> Code: a function (not a closure): same format as String. Symbol: a language symbol (say a python symbol). same format as String. Code With Scope: <total size>=""><String><Object>

Constructor & Destructor Documentation

bson::BSONObj::BSONObj	(	const char *	msgdata,
		bool	check = `true`
	)

inlineexplicit

Construct a BSONObj from data in the proper format.

owned = whether this object owns this buffer.

bson::BSONObj::BSONObj ( holder_type holder )

inlineexplicit

Construct a BSONObj from data in the proper format.

Use this constructor when you want BSONObj to free(holder) when it is no longer needed BSONObj::Holder has an extra 4 bytes for a ref-count before the start of the object

bson::BSONObj::BSONObj ( )

Construct an empty BSONObj – that is, {}.

Member Function Documentation

BSONObjIterator bson::BSONObj::begin ( ) const

use something like this: for( BSONObj::iterator i = myObj.begin(); i.more(); ) { BSONElement e = i.next(); ...

}

BSONObj bson::BSONObj::copy ( ) const

Returns: a new full (and owned) copy of the object.

BSONObj bson::BSONObj::extractFields	(	const BSONObj &	pattern,
		bool	fillWithNull = `false`
	)		const

extract items from object which match a pattern object.

e.g., if pattern is { x : 1, y : 1 }, builds an object with x and y elements of this object, if they are present. returns elements with original field names

BSONElement bson::BSONObj::firstElement ( ) const

inline

Returns: first field of the object

bool bson::BSONObj::getBoolField ( const char * name ) const

Returns: false if not present

See Also: BSONElement::trueValue()

BSONElement bson::BSONObj::getField ( const StringData & name ) const

Get the field of the specified name.

eoo() is true on the returned element if not found.

BSONElement bson::BSONObj::getFieldDotted ( const char * name ) const

Returns: the specified element. element.eoo() will be true if not found.

Parameters

name	field to find. supports dot (".") notation to reach into embedded objects. for example "x.y" means "in the nested object in field x, retrieve field y"

BSONElement bson::BSONObj::getFieldDotted ( const string & name ) const

inline

Returns: the specified element. element.eoo() will be true if not found.

Parameters

name	field to find. supports dot (".") notation to reach into embedded objects. for example "x.y" means "in the nested object in field x, retrieve field y"

BSONElement bson::BSONObj::getFieldDottedOrArray ( const char *& name ) const

Like getFieldDotted(), but returns first array encountered while traversing the dotted fields of name.

The name variable is updated to represent field names with respect to the returned element.

int bson::BSONObj::getFieldNames ( set< string > & fields ) const

adds the field names to the fields set.

does NOT clear it (appends).

void bson::BSONObj::getFields	(	unsigned	n,
		const char **	fieldNames,
		BSONElement *	fields
	)		const

Get several fields at once.

This is faster than separate getField() calls as the size of elements iterated can then be calculated only once each.

Parameters

n	number of fieldNames, and number of elements in the fields array
fields	if a field is found its element is stored in its corresponding position in this array. if not found the array element is unchanged.

void bson::BSONObj::getFieldsDotted	(	const StringData &	name,
		BSONElementSet &	ret
	)		const

Like getFieldDotted(), but expands arrays and returns all matching objects.

TODO(jbenet). trace bool expandLastArray param.

int bson::BSONObj::getIntField ( const char * name ) const

Returns: INT_MIN if not present - does some type conversions

BSONObj bson::BSONObj::getObjectField ( const char * name ) const

Returns: subobject of the given name

bool bson::BSONObj::getObjectID ( BSONElement & e ) const

Get the _id field from the object.

For good performance drivers should assure that _id is the first element of the object; however, correct operation is assured regardless.

Returns: true if found

BSONObj bson::BSONObj::getOwned ( ) const

assure the data buffer is under the control of this BSONObj and not a remote buffer

See Also: isOwned()

const char* bson::BSONObj::getStringField ( const char * name ) const

Returns: "" if DNE or wrong type

bool bson::BSONObj::hasElement ( const char * name ) const

inline

Returns: true if field exists

bool bson::BSONObj::hasField ( const char * name ) const

inline

Returns: true if field exists

int bson::BSONObj::hash ( ) const

inline

Returns: A hash code for the object

bool bson::BSONObj::isEmpty ( ) const

inline

Returns: true if object is empty – i.e., {}

bool bson::BSONObj::isOwned ( ) const

inline

A BSONObj can use a buffer it "owns" or one it does not.

OWNED CASE If the BSONObj owns the buffer, the buffer can be shared among several BSONObj's (by assignment). In this case the buffer is basically implemented as a shared_ptr. Since BSONObj's are typically immutable, this works well.

UNOWNED CASE A BSONObj can also point to BSON data in some other data structure it does not "own" or free later. For example, in a memory mapped file. In this case, it is important the original data stays in scope for as long as the BSONObj is in use. If you think the original data may go out of scope, call BSONObj::getOwned() to promote your BSONObj to having its own copy.

On a BSONObj assignment, if the source is unowned, both the source and dest will have unowned pointers to the original buffer after the assignment.

If you are not sure about ownership but need the buffer to last as long as the BSONObj, call getOwned(). getOwned() is a no-op if the buffer is already owned. If not already owned, a malloc and memcpy will result.

Most ways to create BSONObj's create 'owned' variants. Unowned versions can be created with: (1) specifying true for the ifree parameter in the constructor (2) calling BSONObjBuilder::done(). Use BSONObjBuilder::obj() to get an owned copy (3) retrieving a subobject retrieves an unowned pointer into the parent BSON object

Returns: true if this is in owned mode

bool bson::BSONObj::isValid ( ) const

performs a cursory check on the object's size only.

string bson::BSONObj::jsonString	(	JsonStringFormat	format = `Strict`,
		int	pretty = `0`
	)		const

Properly formatted JSON string.

Parameters

pretty if true we try to add some lf's and indentation

string bson::BSONObj::md5 ( ) const

Returns: an md5 value for this object.

const char* bson::BSONObj::objdata ( ) const

inline

Returns: the raw data of the object

int bson::BSONObj::objsize ( ) const

inline

Returns: total size of the BSON object in bytes

bool bson::BSONObj::okForStorage ( ) const

Returns: if the user is a valid user doc criter: isValid() no . or $ field names

BSONElement bson::BSONObj::operator[] ( const char * field ) const

inline

Get the field of the specified name.

eoo() is true on the returned element if not found.

BSONObj bson::BSONObj::replaceFieldNames ( const BSONObj & obj ) const

Return new object with the field names replaced by those in the passed object.

bool bson::BSONObj::shallowEqual ( const BSONObj & r ) const

inline

This is "shallow equality" – ints and doubles won't match.

for a deep equality test use woCompare (which is slower).

string bson::BSONObj::toString	(	bool	isArray = `false`,
		bool	full = `false`,
		bool	noThrow = `true`
	)		const

Readable representation of a BSON object in an extended JSON-style notation.

This is an abbreviated representation which might be used for logging.

template<class T >

void bson::BSONObj::Vals ( vector< T > & ) const

add all values of the object to the specified vector.

If type mismatches, exception. this is most useful when the BSONObj is an array, but can be used with non-arrays too in theory.

example: bo sub = y["subobj"].Obj(); vector<int> myints; sub.Vals(myints);

template<class T >

void bson::BSONObj::Vals ( list< T > & ) const

add all values of the object to the specified list.

If type mismatches, exception.

template<class T >

void bson::BSONObj::vals ( vector< T > & ) const

add all values of the object to the specified vector.

If type mismatches, skip.

template<class T >

void bson::BSONObj::vals ( list< T > & ) const

add all values of the object to the specified list.

If type mismatches, skip.

int bson::BSONObj::woCompare	(	const BSONObj &	r,
		const Ordering &	o,
		bool	considerFieldName = `true`
	)		const

wo='well ordered'.

fields must be in same order in each object. Ordering is with respect to the signs of the elements and allows ascending / descending key mixing.

Returns: <0 if l<r. 0 if l==r. >0 if l>r

int bson::BSONObj::woCompare	(	const BSONObj &	r,
		const BSONObj &	ordering = `BSONObj()`,
		bool	considerFieldName = `true`
	)		const

wo='well ordered'.

fields must be in same order in each object. Ordering is with respect to the signs of the elements and allows ascending / descending key mixing.

Returns: <0 if l<r. 0 if l==r. >0 if l>r

int bson::BSONObj::woSortOrder	(	const BSONObj &	r,
		const BSONObj &	sortKey,
		bool	useDotted = `false`
	)		const

Parameters

useDotted whether to treat sort key fields as possibly dotted and expand into them

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

bsonobj.h

Classes

Public Types

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation