root/ROOT/RRawFileDavix.hxx

0001 // @(#)root/io:$Id$
0002 // Author: Jakob Blomer
0003
0004 /*************************************************************************
0005  * Copyright (C) 1995-2018, Rene Brun and Fons Rademakers.               *
0006  * All rights reserved.                                                  *
0007  *                                                                       *
0008  * For the licensing terms see $ROOTSYS/LICENSE.                         *
0009  * For the list of contributors see $ROOTSYS/README/CREDITS.             *
0010  *************************************************************************/
0011
0012 #ifndef ROOT_RRawFileDavix
0013 #define ROOT_RRawFileDavix
0014
0015 #include <ROOT/RRawFile.hxx>
0016 #include <string_view>
0017
0018 #include <cstddef>
0019 #include <cstdint>
0020 #include <memory>
0021
0022 namespace ROOT {
0023 namespace Internal {
0024
0025 struct RDavixFileDes;
0026
0027 /** \class RRawFileDavix RRawFileDavix.hxx
0028
0029 The RRawFileDavix class provides read-only access to remote non-ROOT files.  It uses the Davix library for
0030 the transport layer.  It instructs the RRawFile base class to buffer in larger chunks than the default for
0031 local files, assuming that remote file access has high(er) latency.
0032
0033 */
0034
0035 class RRawFileDavix : public RRawFile {
0036 private:
0037    std::unique_ptr<Internal::RDavixFileDes> fFileDes;
0038
0039 protected:
0040    void OpenImpl() final;
0041    size_t ReadAtImpl(void *buffer, size_t nbytes, std::uint64_t offset) final;
0042    void ReadVImpl(RIOVec *ioVec, unsigned int nReq) final;
0043    std::uint64_t GetSizeImpl() final;
0044
0045 public:
0046    RRawFileDavix(std::string_view url, RRawFile::ROptions options);
0047    ~RRawFileDavix();
0048    std::unique_ptr<RRawFile> Clone() const final;
0049    int GetFeatures() const final { return kFeatureHasSize; }
0050 };
0051
0052 } // namespace Internal
0053 } // namespace ROOT
0054
0055 #endif