ROOT::Internal::RRawFileDavix Class Reference

The RRawFileDavix class provides read-only access to remote non-ROOT files.

It uses the Davix library for the transport layer. It instructs the RRawFile base class to buffer in larger chunks than the default for local files, assuming that remote file access has high(er) latency.

Definition at line 35 of file RRawFileDavix.hxx.

Public Member Functions
	RRawFileDavix (std::string_view url, RRawFile::ROptions options)
	~RRawFileDavix ()
std::unique_ptr< RRawFile >	Clone () const final
	Create a new RawFile that accesses the same resource. The file pointer is reset to zero.
Public Member Functions inherited from ROOT::Internal::RRawFile
	RRawFile (const RRawFile &)=delete
	RRawFile (std::string_view url, ROptions options)
virtual	~RRawFile ()=default
std::uint64_t	GetFilePos () const
	Returns the offset for the next Read/Readln call.
virtual RIOVecLimits	GetReadVLimits ()
	Returns the limits regarding the ioVec input to ReadV for this specific file; may open the file as a side-effect.
std::uint64_t	GetSize ()
	Returns the size of the file.
std::string	GetUrl () const
	Returns the url of the file.
bool	IsBuffering () const
bool	IsOpen () const
	Once opened, the file stay open until destruction of the RRawFile object.
RRawFile &	operator= (const RRawFile &)=delete
size_t	Read (void *buffer, size_t nbytes)
	Read from fFilePos offset. Returns the actual number of bytes read.
size_t	ReadAt (void *buffer, size_t nbytes, std::uint64_t offset)
	Buffered read from a random position.
bool	Readln (std::string &line)
	Read the next line starting from the current value of fFilePos. Returns false if the end of the file is reached.
void	ReadV (RIOVec *ioVec, unsigned int nReq)
	Opens the file if necessary and calls ReadVImpl.
void	Seek (std::uint64_t offset)
	Change the cursor fFilePos.
void	SetBuffering (bool value)
	Turn off buffered reads; all scalar read requests go directly to the implementation.

Protected Member Functions
std::uint64_t	GetSizeImpl () final
	Derived classes should return the file size.
void	OpenImpl () final
	OpenImpl() is called at most once and before any call to either DoReadAt or DoGetSize.
size_t	ReadAtImpl (void *buffer, size_t nbytes, std::uint64_t offset) final
	Derived classes should implement low-level reading without buffering.
void	ReadVImpl (RIOVec *ioVec, unsigned int nReq) final
	By default implemented as a loop of ReadAt calls but can be overwritten, e.g. XRootD or DAVIX implementations.
Protected Member Functions inherited from ROOT::Internal::RRawFile
void	EnsureOpen ()
	Open the file if not already open. Otherwise noop.

Private Attributes
std::unique_ptr< Internal::RDavixFileDes >	fFileDes

Additional Inherited Members
Public Types inherited from ROOT::Internal::RRawFile
enum class	ELineBreaks { kAuto , kSystem , kUnix , kWindows }
	kAuto detects the line break from the first line, kSystem picks the system's default More...
Static Public Member Functions inherited from ROOT::Internal::RRawFile
static std::unique_ptr< RRawFile >	Create (std::string_view url, ROptions options=ROptions())
	Factory method that returns a suitable concrete implementation according to the transport in the url.
static std::string	GetLocation (std::string_view url)
	Returns only the file location, e.g. "server/file" for http://server/file.
static std::string	GetTransport (std::string_view url)
	Returns only the transport protocol in lower case, e.g. "http" for HTTP://server/file.
Protected Attributes inherited from ROOT::Internal::RRawFile
std::uint64_t	fFilePos = 0
	The current position in the file, which can be changed by Seek, Read, and Readln.
ROptions	fOptions
std::string	fUrl

#include <ROOT/RRawFileDavix.hxx>

Inheritance diagram for ROOT::Internal::RRawFileDavix:

Constructor & Destructor Documentation

RRawFileDavix()

ROOT::Internal::RRawFileDavix::RRawFileDavix	(	std::string_view	url,
		RRawFile::ROptions	options
	)

Definition at line 45 of file RRawFileDavix.cxx.

~RRawFileDavix()

ROOT::Internal::RRawFileDavix::~RRawFileDavix

(

)

Definition at line 50 of file RRawFileDavix.cxx.

Member Function Documentation

Clone()

std::unique_ptr< ROOT::Internal::RRawFile > ROOT::Internal::RRawFileDavix::Clone ( ) const

finalvirtual

Create a new RawFile that accesses the same resource. The file pointer is reset to zero.

Implements ROOT::Internal::RRawFile.

Definition at line 56 of file RRawFileDavix.cxx.

GetSizeImpl()

std::uint64_t ROOT::Internal::RRawFileDavix::GetSizeImpl ( )

finalprotectedvirtual

Derived classes should return the file size.

Implements ROOT::Internal::RRawFile.

Definition at line 61 of file RRawFileDavix.cxx.

OpenImpl()

void ROOT::Internal::RRawFileDavix::OpenImpl ( )

finalprotectedvirtual

OpenImpl() is called at most once and before any call to either DoReadAt or DoGetSize.

If fOptions.fBlocksize is negative, derived classes are responsible to set a sensible value. After a call to OpenImpl(), fOptions.fBlocksize must be larger or equal to zero.

Implements ROOT::Internal::RRawFile.

Definition at line 71 of file RRawFileDavix.cxx.

ReadAtImpl()

size_t ROOT::Internal::RRawFileDavix::ReadAtImpl ( void *  buffer, size_t  nbytes, std::uint64_t  offset  )

finalprotectedvirtual

Derived classes should implement low-level reading without buffering.

Short reads indicate the end of the file, therefore derived classes should return nbytes bytes if available.

Implements ROOT::Internal::RRawFile.

Definition at line 82 of file RRawFileDavix.cxx.

ReadVImpl()

void ROOT::Internal::RRawFileDavix::ReadVImpl ( RIOVec *  ioVec, unsigned int  nReq  )

finalprotectedvirtual

By default implemented as a loop of ReadAt calls but can be overwritten, e.g. XRootD or DAVIX implementations.

Reimplemented from ROOT::Internal::RRawFile.

Definition at line 92 of file RRawFileDavix.cxx.

Member Data Documentation

fFileDes

std::unique_ptr<Internal::RDavixFileDes> ROOT::Internal::RRawFileDavix::fFileDes

private

Definition at line 37 of file RRawFileDavix.hxx.

Libraries for ROOT::Internal::RRawFileDavix:

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

• net/davix/inc/ROOT/RRawFileDavix.hxx
• net/davix/src/RRawFileDavix.cxx