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.

int	GetFeatures () const final
	Derived classes shall inform the user about the supported functionality, which can possibly depend on the file at hand.

Public Member Functions inherited from ROOT::Internal::RRawFile
	RRawFile (const RRawFile &)=delete

	RRawFile (std::string_view url, ROptions options)

virtual	~RRawFile ()

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	IsOpen () const
	Once opened, the file stay open until destruction of the RRawFile object.

void *	Map (size_t nbytes, std::uint64_t offset, std::uint64_t &mapdOffset)
	Memory mapping according to POSIX standard; in particular, new mappings of the same range replace older ones.

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	Unmap (void *region, size_t nbytes)
	Receives a pointer returned by Map() and should have nbytes set to the full length of the mapping.

Protected Member Functions
std::uint64_t	GetSizeImpl () final
	Derived classes should return the file size or kUnknownFileSize.

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.

virtual void *	MapImpl (size_t nbytes, std::uint64_t offset, std::uint64_t &mapdOffset)
	If a derived class supports mmap, the MapImpl and UnmapImpl calls are supposed to be implemented, too The default implementation throws an error.

virtual void	UnmapImpl (void *region, size_t nbytes)
	Derived classes with mmap support must be able to unmap the memory area handed out by Map()

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.

Static Public Attributes inherited from ROOT::Internal::RRawFile
static constexpr int	kFeatureHasAsyncIo = 0x04
	File supports async IO.

static constexpr int	kFeatureHasMmap = 0x02
	Map() and Unmap() are implemented.

static constexpr int	kFeatureHasSize = 0x01
	GetSize() does not return kUnknownFileSize.

static constexpr std::uint64_t	kUnknownFileSize = std::uint64_t(-1)
	Derived classes do not necessarily need to provide file size information but they can return "not known" instead.

Protected Attributes inherited from ROOT::Internal::RRawFile
std::uint64_t	fFilePos
	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:

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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.

◆ GetFeatures()

int ROOT::Internal::RRawFileDavix::GetFeatures ( ) const

inlinefinalvirtual

Derived classes shall inform the user about the supported functionality, which can possibly depend on the file at hand.

Implements ROOT::Internal::RRawFile.

Definition at line 49 of file RRawFileDavix.hxx.

◆ GetSizeImpl()

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

finalprotectedvirtual

Derived classes should return the file size or kUnknownFileSize.

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

Public Member Functions

Protected Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ RRawFileDavix()

◆ ~RRawFileDavix()

Member Function Documentation

◆ Clone()

◆ GetFeatures()

◆ GetSizeImpl()

◆ OpenImpl()

◆ ReadAtImpl()

◆ ReadVImpl()

Member Data Documentation

◆ fFileDes