pqxx::largeobjectaccess Class Reference

Accessor for large object's contents. More...

#include <largeobject.hxx>

Inheritance diagram for pqxx::largeobjectaccess:

Collaboration diagram for pqxx::largeobjectaccess:

Public Types
typedef long	off_type
typedef PGSTD::ios::openmode	openmode
	Open mode: in, out (can be combined with the "or" operator) More...
typedef size_type	pos_type
typedef PGSTD::ios::seekdir	seekdir
	Seek direction: beg, cur, end. More...
typedef long	size_type

Public Member Functions
	largeobjectaccess (dbtransaction &T, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Create new large object and open it. More...
	largeobjectaccess (dbtransaction &T, oid O, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Open large object with given oid. More...
	largeobjectaccess (dbtransaction &T, largeobject O, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Open given large object. More...
	largeobjectaccess (dbtransaction &T, const PGSTD::string &File, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Import large object from a local file and open it. More...
	~largeobjectaccess () throw ()
void	to_file (const PGSTD::string &File) const
	Export large object's contents to a local file. More...
High-level access to object contents
void	write (const char Buf[], size_type Len)
	Write data to large object. More...
void	write (const PGSTD::string &Buf)
	Write string to large object. More...
size_type	read (char Buf[], size_type Len)
	Read data from large object. More...
size_type	seek (size_type dest, seekdir dir)
	Seek in large object's data stream. More...
size_type	tell () const
	Report current position in large object's data stream. More...
Low-level access to object contents
These functions provide a more "C-like" access interface, returning special values instead of throwing exceptions on error. These functions are generally best avoided in favour of the high-level access functions, which behave more like C++ functions should.
pos_type	cseek (off_type dest, seekdir dir) throw ()
	Seek in large object's data stream. More...
off_type	cwrite (const char Buf[], size_type Len) throw ()
	Write to large object's data stream. More...
off_type	cread (char Buf[], size_type Len) throw ()
	Read from large object's data stream. More...
pos_type	ctell () const throw ()
	Report current position in large object's data stream. More...
Error/warning output
void	process_notice (const PGSTD::string &) throw ()
	Issue message to transaction's notice processor. More...

Private Member Functions
	largeobjectaccess ()
	largeobjectaccess (const largeobjectaccess &)
void	close () throw ()
oid	id () const throw ()
	Object identifier. More...
void	open (openmode mode)
largeobjectaccess	operator= (const largeobjectaccess &)
internal::pq::PGconn *	RawConnection () const
PGSTD::string PQXX_PRIVATE	Reason (int err) const
void	remove (dbtransaction &T) const
	Delete large object from database. More...
void	to_file (dbtransaction &T, const PGSTD::string &File) const
	Export large object's contents to a local file. More...
Identity comparisons
These operators compare the object identifiers of large objects. This has nothing to do with the objects' actual contents; use them only for keeping track of containers of references to large objects and such.
bool	operator== (const largeobject &other) const
	Compare object identities. More...
bool	operator!= (const largeobject &other) const
	Compare object identities. More...
bool	operator<= (const largeobject &other) const
	Compare object identities. More...
bool	operator>= (const largeobject &other) const
	Compare object identities. More...
bool	operator< (const largeobject &other) const
	Compare object identities. More...
bool	operator> (const largeobject &other) const
	Compare object identities. More...

Static Private Member Functions
static internal::pq::PGconn *PQXX_PURE	RawConnection (const dbtransaction &T)

Private Attributes
int	m_fd
dbtransaction &	m_Trans

Detailed Description

Accessor for large object's contents.

Member Typedef Documentation

typedef long pqxx::largeobjectaccess::off_type

typedef PGSTD::ios::openmode pqxx::largeobjectaccess::openmode

Open mode: in, out (can be combined with the "or" operator)

According to the C++ standard, these should be in std::ios_base. We take them from std::ios instead, which should be safe because it inherits the same definition, to accommodate gcc 2.95 & 2.96.

typedef size_type pqxx::largeobjectaccess::pos_type

typedef PGSTD::ios::seekdir pqxx::largeobjectaccess::seekdir

Seek direction: beg, cur, end.

According to the C++ standard, these should be in std::ios_base. We take them from std::ios instead, which should be safe because it inherits the same definition, to accommodate gcc 2.95 & 2.96.

typedef long pqxx::largeobject::size_type

Constructor & Destructor Documentation

pqxx::largeobjectaccess::largeobjectaccess ( dbtransaction &  T, openmode  mode = PGSTD::ios::in|PGSTD::ios::out  )

explicit

Create new large object and open it.

Parameters

T	Backend transaction in which the object is to be created
mode	Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::largeobjectaccess	(	dbtransaction &	T,
		oid	O,
		openmode	mode = PGSTD::ios::in|PGSTD::ios::out
	)

Open large object with given oid.

Convert combination of a transaction and object identifier into a large object identity. Does not affect the database.

Parameters

T	Transaction in which the object is to be accessed
O	Object identifier for the given object
mode	Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::largeobjectaccess	(	dbtransaction &	T,
		largeobject	O,
		openmode	mode = PGSTD::ios::in|PGSTD::ios::out
	)

Open given large object.

Open a large object with the given identity for reading and/or writing

Parameters

T	Transaction in which the object is to be accessed
O	Identity for the large object to be accessed
mode	Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::largeobjectaccess	(	dbtransaction &	T,
		const PGSTD::string &	File,
		openmode	mode = PGSTD::ios::in|PGSTD::ios::out
	)

Import large object from a local file and open it.

Creates a large object containing the data found in the given file.

Parameters

T	Backend transaction in which the large object is to be created
File	A filename on the client program's filesystem
mode	Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::~largeobjectaccess ( ) throw ()

inline

pqxx::largeobjectaccess::largeobjectaccess ( )

private

pqxx::largeobjectaccess::largeobjectaccess ( const largeobjectaccess &  )

private

Member Function Documentation

void pqxx::largeobjectaccess::close ( ) throw ()

private

off_type pqxx::largeobjectaccess::cread	(	char	Buf[],
		size_type	Len
	)		throw ()

Read from large object's data stream.

Does not throw exception in case of error; inspect return value and errno instead.

Parameters

Buf	Area where incoming bytes should be stored
Len	Number of bytes to read

Returns

Number of bytes actually read, or -1 if an error occurred.

pos_type pqxx::largeobjectaccess::cseek	(	off_type	dest,
		seekdir	dir
	)		throw ()

Seek in large object's data stream.

Does not throw exception in case of error; inspect return value and errno instead.

Parameters

dest	Offset to go to
dir	Origin to which dest is relative: ios_base::beg (from beginning of the object), ios_base::cur (from current access position), or ios_base;:end (from end of object)

Returns

New position in large object, or -1 if an error occurred.

pos_type pqxx::largeobjectaccess::ctell

(

)

const throw ()

Report current position in large object's data stream.

Does not throw exception in case of error; inspect return value and errno instead.

Returns

Current position in large object, of -1 if an error occurred.

off_type pqxx::largeobjectaccess::cwrite	(	const char	Buf[],
		size_type	Len
	)		throw ()

Write to large object's data stream.

Does not throw exception in case of error; inspect return value and errno instead.

Parameters

Buf	Data to write
Len	Number of bytes to write

Returns

Number of bytes actually written, or -1 if an error occurred.

oid pqxx::largeobject::id ( ) const throw ()

inlineinherited

Object identifier.

The number returned by this function identifies the large object in the database we're connected to (or oid_none is returned if we refer to the null object).

void pqxx::largeobjectaccess::open ( openmode  mode )

private

bool pqxx::largeobject::operator!= ( const largeobject &  other ) const

inlineinherited

Compare object identities.

Warning

Only valid between large objects in the same database.

bool pqxx::largeobject::operator< ( const largeobject &  other ) const

inlineinherited

Compare object identities.

Warning

Only valid between large objects in the same database.

bool pqxx::largeobject::operator<= ( const largeobject &  other ) const

inlineinherited

Compare object identities.

Warning

Only valid between large objects in the same database.

largeobjectaccess pqxx::largeobjectaccess::operator= ( const largeobjectaccess &  )

private

bool pqxx::largeobject::operator== ( const largeobject &  other ) const

inlineinherited

Compare object identities.

Warning

Only valid between large objects in the same database.

bool pqxx::largeobject::operator> ( const largeobject &  other ) const

inlineinherited

Compare object identities.

Warning

Only valid between large objects in the same database.

bool pqxx::largeobject::operator>= ( const largeobject &  other ) const

inlineinherited

Compare object identities.

Warning

Only valid between large objects in the same database.

void pqxx::largeobjectaccess::process_notice

(

const PGSTD::string &

)

throw ()

Issue message to transaction's notice processor.

static internal::pq::PGconn* PQXX_PURE pqxx::largeobject::RawConnection ( const dbtransaction &  T )

staticprotectedinherited

Referenced by RawConnection().

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internal::pq::PGconn* pqxx::largeobjectaccess::RawConnection ( ) const

inlineprivate

References pqxx::largeobject::RawConnection().

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size_type pqxx::largeobjectaccess::read	(	char	Buf[],
		size_type	Len
	)

Read data from large object.

Throws an exception if an error occurs while reading.

Parameters

Buf	Location to store the read data in
Len	Number of bytes to try and read

Returns

Number of bytes read, which may be less than the number requested if the end of the large object is reached

PGSTD::string PQXX_PRIVATE pqxx::largeobjectaccess::Reason ( int  err ) const

private

void pqxx::largeobject::remove ( dbtransaction &  T ) const

inherited

Delete large object from database.

Unlike its low-level equivalent cunlink, this will throw an exception if deletion fails.

Parameters

T	Transaction in which the object is to be deleted

size_type pqxx::largeobjectaccess::seek	(	size_type	dest,
		seekdir	dir
	)

Seek in large object's data stream.

Throws an exception if an error occurs.

Returns

The new position in the large object

size_type pqxx::largeobjectaccess::tell

(

)

const

Report current position in large object's data stream.

Throws an exception if an error occurs.

Returns

The current position in the large object

void pqxx::largeobject::to_file ( dbtransaction &  T, const PGSTD::string &  File  ) const

inherited

Export large object's contents to a local file.

Writes the data stored in the large object to the given file.

Parameters

T	Transaction in which the object is to be accessed
File	A filename on the client's filesystem

Referenced by to_file().

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void pqxx::largeobjectaccess::to_file ( const PGSTD::string &  File ) const

inline

Export large object's contents to a local file.

Writes the data stored in the large object to the given file.

Parameters

File	A filename on the client's filesystem

References pqxx::largeobject::to_file().

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void pqxx::largeobjectaccess::write	(	const char	Buf[],
		size_type	Len
	)

Write data to large object.

If not all bytes could be written, an exception is thrown.

Parameters

Buf	Data to write
Len	Number of bytes from Buf to write

void pqxx::largeobjectaccess::write ( const PGSTD::string &  Buf )

inline

Write string to large object.

If not all bytes could be written, an exception is thrown.

Parameters

Buf	Data to write; no terminating zero is written

References write().

Referenced by write().

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Member Data Documentation

int pqxx::largeobjectaccess::m_fd

private

dbtransaction& pqxx::largeobjectaccess::m_Trans

private

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

• /usr/include/pqxx/largeobject.hxx