mongocxx::v1::gridfs::downloader Class Reference

#include <mongocxx/v1/gridfs/downloader.hpp>

Description

Support for downloading files from a GridFS bucket.

See also

• GridFS (MongoDB Manual)

Attention

This feature is experimental! It is not ready for use!

Public Types
enum class	errc
	Errors codes which may be returned by mongocxx::v1::gridfs::downloader. More...

Public Member Functions
	downloader ()
	Default initialization.
	downloader (downloader &&other) noexcept
	Move constructor.
	downloader (downloader const &other)=delete
	This class is not copyable.
	~downloader ()
	Destroy this object.
std::int32_t	chunk_size () const
	Return the chunk size (in bytes) of the associated GridFS file.
void	close ()
	Close the underlying GridFS download stream.
std::int64_t	file_length () const
	Return the length of the associated GridFS file.
bsoncxx::v1::document::view	files_document () const
	Return the files collection document for the associated GridFS file.
bool	is_open () const
	Return true when the underlying GridFS file stream is open for reading.
	operator bool () const
	Return true when *this is NOT in an assign-or-destroy-only state and this->is_open() == true.
downloader &	operator= (downloader &&other) noexcept
	Move assignment.
downloader &	operator= (downloader const &other)=delete
	This class is not copyable.
std::size_t	read (std::uint8_t *data, std::size_t length)
	Read up to length bytes of the associated GridFS file.

Static Public Member Functions
static std::error_category const &	error_category ()
	The error category for mongocxx::v1::gridfs::downloader::errc.

Friends
std::error_code	make_error_code (errc v)
	Support implicit conversion to std::error_code.

Member Enumeration Documentation

errc

enum class mongocxx::v1::gridfs::downloader::errc

strong

Errors codes which may be returned by mongocxx::v1::gridfs::downloader.

Attention

This feature is experimental! It is not ready for use!

Enumerator
zero	Zero.
is_closed	The GridFS file download stream is not open.
corrupt_data	The GridFS file is in an invalid or inconsistent state.

Constructor & Destructor Documentation

~downloader()

mongocxx::v1::gridfs::downloader::~downloader

(

)

Destroy this object.

Warning

Invalidates all associated views.

downloader() [1/3]

mongocxx::v1::gridfs::downloader::downloader ( downloader && other )

noexcept

Move constructor.

Postconditions:

• other is in an assign-or-destroy-only state.

downloader() [2/3]

mongocxx::v1::gridfs::downloader::downloader ( downloader const & other )

delete

This class is not copyable.

downloader() [3/3]

mongocxx::v1::gridfs::downloader::downloader

(

)

Default initialization.

Postconditions:

• *this is in an assign-or-destroy-only state.

Member Function Documentation

chunk_size()

std::int32_t mongocxx::v1::gridfs::downloader::chunk_size

(

)

const

Return the chunk size (in bytes) of the associated GridFS file.

close()

void mongocxx::v1::gridfs::downloader::close

(

)

Close the underlying GridFS download stream.

error_category()

std::error_category const & mongocxx::v1::gridfs::downloader::error_category ( )

static

The error category for mongocxx::v1::gridfs::downloader::errc.

Attention

This feature is experimental! It is not ready for use!

file_length()

std::int64_t mongocxx::v1::gridfs::downloader::file_length

(

)

const

Return the length of the associated GridFS file.

files_document()

bsoncxx::v1::document::view mongocxx::v1::gridfs::downloader::files_document

(

)

const

Return the files collection document for the associated GridFS file.

is_open()

bool mongocxx::v1::gridfs::downloader::is_open

(

)

const

Return true when the underlying GridFS file stream is open for reading.

operator bool()

mongocxx::v1::gridfs::downloader::operator bool ( ) const

explicit

Return true when *this is NOT in an assign-or-destroy-only state and this->is_open() == true.

operator=() [1/2]

downloader & mongocxx::v1::gridfs::downloader::operator= ( downloader && other )

noexcept

Move assignment.

Postconditions:

• other is in an assign-or-destroy-only state.

operator=() [2/2]

downloader & mongocxx::v1::gridfs::downloader::operator= ( downloader const & other )

delete

This class is not copyable.

read()

std::size_t mongocxx::v1::gridfs::downloader::read	(	std::uint8_t *	data,
		std::size_t	length )

Read up to length bytes of the associated GridFS file.

Preconditions:

• data is not null.
• The size of the storage region pointed to by data must be greater than or equal to length.

Returns

The actual number of bytes read. 0 indicates the downloader has reached the end of the file.

Exceptions

mongocxx::v1::exception	with mongocxx::v1::gridfs::downloader::errc::is_closed if the underlying GridFS download stream was already closed.
mongocxx::v1::exception	with mongocxx::v1::gridfs::downloader::errc::corrupt_data if the GridFS file data is invalid or inconsistent.

Friends And Related Symbol Documentation

make_error_code

std::error_code make_error_code ( errc v )

friend

Support implicit conversion to std::error_code.

Attention

This feature is experimental! It is not ready for use!

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

• mongocxx/v1/gridfs/downloader.hpp