// @(#)root/gfal:$Name:  $:$Id: TGFALFile.cxx,v 1.7 2007/05/23 13:30:55 rdm Exp $
// Author: Fons Rademakers   8/12/2005

/*************************************************************************
 * Copyright (C) 1995-2005, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

//////////////////////////////////////////////////////////////////////////
//                                                                      //
// TGFALFile                                                            //
//                                                                      //
// A TGFALFile is like a normal TFile except that it reads and writes   //
// its data via the underlaying Grid access mechanism.                  //
// TGFALFile file names are either a logical file name, a guid, an      //
// SURL or a TURL, like:                                                //
//                                                                      //
//    gfal:/lfn/user/r/rdm/galice.root                                  //
//                                                                      //
// Grid storage interactions today require using several existing       //
// software components:                                                 //
//  - The replica catalog services to locate valid replicas of          //
//    files.                                                            //
//  - The SRM software to ensure:                                       //
//     - files  exist on disk (they are recalled from mass              //
//       storage if necessary) or                                       //
//     - space is allocated on disk for new files (they are possibly    //
//       migrated to mass storage later)                                //
//  - A file access mechanism to access files from the storage          //
//    system on the worker node.                                        //
//                                                                      //
// The GFAL library hides these interactions and presents a Posix       //
// interface for the I/O operations. The currently supported protocols  //
// are: file for local access, dcap, gsidcap and kdcap (dCache access   //
// protocol) and rfio (CASTOR access protocol).                         //
//                                                                      //
// File naming convention:                                              //
// A file name can be a Logical File Name (LFN), a Grid Unique          //
// IDentifier (GUID), a file replica (SURL) or a Transport file         //
// name (TURL):                                                         //
//                                                                      //
//     an LFN starts with lfn:                                          //
//        for example lfn:baud/testgfal15                               //
//                                                                      //
//     a GUID starts with guid:                                         //
//        for example guid:2cd59291-7ae7-4778-af6d-b1f423719441         //
//                                                                      //
//     an SURL starts with srm://                                       //
//         for example srm://wacdr002d.cern.ch:8443/castor/             //
//                    cern.ch/user/b/baud/testgfal15                    //
//                                                                      //
//      a TURL starts with a protocol name:                             //
//          for example rfio:///castor/cern.ch/user/b/baud/testgfal15   //
//                                                                      //
// Note that for the TGFALFile plugin to work, all these pathnames      //
// should be prepended by gfal:.                                        //
//                                                                      //
//////////////////////////////////////////////////////////////////////////

#include "TGFALFile.h"
#include "TROOT.h"
#include "TUrl.h"

extern "C" {
#include <gfal_api.h>
}

ClassImp(TGFALFile)
ClassImp(TGFALSystem)

//______________________________________________________________________________
TGFALFile::TGFALFile(const char *url, Option_t *option, const char *ftitle,
                     Int_t compress)
         : TFile(url, "NET", ftitle, compress)
{
   // Create a GFAL file object. A GFAL file is the same as a TFile
   // except that it is being accessed via the underlaying Grid access
   // mechanism. The url argument must be of the form: gfal:/lfn/file.root
   // If the file specified in the URL does not exist, is not accessable
   // or can not be created the kZombie bit will be set in the TGFALFile
   // object. Use IsZombie() to see if the file is accessable.
   // For a description of the option and other arguments see the TFile ctor.
   // The preferred interface to this constructor is via TFile::Open().

   fStatCached = kFALSE;

   fOption = option;
   fOption.ToUpper();

   if (fOption == "NEW")
      fOption = "CREATE";

   Bool_t create   = (fOption == "CREATE") ? kTRUE : kFALSE;
   Bool_t recreate = (fOption == "RECREATE") ? kTRUE : kFALSE;
   Bool_t update   = (fOption == "UPDATE") ? kTRUE : kFALSE;
   Bool_t read     = (fOption == "READ") ? kTRUE : kFALSE;
   if (!create && !recreate && !update && !read) {
      read    = kTRUE;
      fOption = "READ";
   }

   TString stmp;
   char *fname;
   if ((fname = gSystem->ExpandPathName(fUrl.GetFile()))) {
      stmp = fname;
      delete [] fname;
      fname = (char *)stmp.Data();
   } else {
      Error("TGFALFile", "error expanding path %s", fUrl.GetFile());
      goto zombie;
   }

   if (recreate) {
      if (::gfal_access(fname, kFileExists) == 0)
         ::gfal_unlink(fname);
      recreate = kFALSE;
      create   = kTRUE;
      fOption  = "CREATE";
   }
   if (create && ::gfal_access(fname, kFileExists) == 0) {
      Error("TGFALFile", "file %s already exists", fname);
      goto zombie;
   }
   if (update) {
      if (::gfal_access(fname, kFileExists) != 0) {
         update = kFALSE;
         create = kTRUE;
      }
      if (update && ::gfal_access(fname, kWritePermission) != 0) {
         Error("TGFALFile", "no write permission, could not open file %s", fname);
         goto zombie;
      }
   }
   if (read) {
#ifdef GFAL_ACCESS_FIXED
      if (::gfal_access(fname, kFileExists) != 0) {
         Error("TGFALFile", "file %s does not exist", fname);
         goto zombie;
      }
      if (::gfal_access(fname, kReadPermission) != 0) {
         Error("TGFALFile", "no read permission, could not open file %s", fname);
         goto zombie;
      }
#endif
   }

   // Connect to file system stream
   fRealName = fname;

   if (create || update) {
#ifndef WIN32
      fD = SysOpen(fname, O_RDWR | O_CREAT, 0644);
#else
      fD = SysOpen(fname, O_RDWR | O_CREAT | O_BINARY, S_IREAD | S_IWRITE);
#endif
      if (fD == -1) {
         SysError("TGFALFile", "file %s can not be opened", fname);
         goto zombie;
      }
      fWritable = kTRUE;
   } else {
#ifndef WIN32
      fD = SysOpen(fname, O_RDONLY, 0644);
#else
      fD = SysOpen(fname, O_RDONLY | O_BINARY, S_IREAD | S_IWRITE);
#endif
      if (fD == -1) {
         SysError("TGFALFile", "file %s can not be opened for reading", fname);
         goto zombie;
      }
      fWritable = kFALSE;
   }

   Init(create);

   return;

zombie:
   // error in file opening occured, make this object a zombie
   MakeZombie();
   gDirectory = gROOT;
}

//______________________________________________________________________________
TGFALFile::~TGFALFile()
{
   // GFAL file dtor. Close and flush directory structure.

   Close();
}

//______________________________________________________________________________
Int_t TGFALFile::SysOpen(const char *pathname, Int_t flags, UInt_t mode)
{
   // Interface to system open. All arguments like in POSIX open.

   Int_t ret = ::gfal_open64(pathname, flags, (Int_t) mode);

   return ret;
}

//______________________________________________________________________________
Int_t TGFALFile::SysClose(Int_t fd)
{
   // Interface to system close. All arguments like in POSIX close.

   Int_t ret = ::gfal_close(fd);

   return ret;
}

//______________________________________________________________________________
Int_t TGFALFile::SysRead(Int_t fd, void *buf, Int_t len)
{
   // Interface to system read. All arguments like in POSIX read.

   fOffset += len;
   Int_t ret = ::gfal_read(fd, buf, len);

   return ret;
}

//______________________________________________________________________________
Int_t TGFALFile::SysWrite(Int_t fd, const void *buf, Int_t len)
{
   // Interface to system write. All arguments like in POSIX write.

   fOffset += len;
   Int_t ret = ::gfal_write(fd, buf, len);

   return ret;
}

//______________________________________________________________________________
Long64_t TGFALFile::SysSeek(Int_t fd, Long64_t offset, Int_t whence)
{
   // Interface to system lseek. All arguments like in POSIX lseek
   // except that the offset and return value are Long_t to be able to
   // handle 64 bit file systems.

   if (whence == SEEK_SET && offset == fOffset) return offset;

   Long64_t ret = ::gfal_lseek64(fd, offset, whence);

   if (ret >= 0)
      fOffset = ret;

   return ret;
}

//______________________________________________________________________________
Int_t TGFALFile::SysStat(Int_t /*fd*/, Long_t *id, Long64_t *size, Long_t *flags,
                         Long_t *modtime)
{
   // Interface to TSystem:GetPathInfo(). Generally implemented via
   // stat() or fstat().

   struct stat64 &statbuf = fStatBuffer;

   if (fOption != "READ" || !fStatCached) {
      // We are not in read mode, or the file status information is not yet
      // in the cache. Update or read the status information with gfal_stat().

      if (::gfal_stat64(fRealName, &statbuf) >= 0)
         fStatCached = kTRUE;
   }

   if (fStatCached) {
      if (id)
         *id = (statbuf.st_dev << 24) + statbuf.st_ino;
      if (size)
         *size = statbuf.st_size;
      if (modtime)
         *modtime = statbuf.st_mtime;
      if (flags) {
         *flags = 0;
         if (statbuf.st_mode & ((S_IEXEC)|(S_IEXEC>>3)|(S_IEXEC>>6)))
            *flags |= 1;
         if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
            *flags |= 2;
         if ((statbuf.st_mode & S_IFMT) != S_IFREG &&
             (statbuf.st_mode & S_IFMT) != S_IFDIR)
            *flags |= 4;
      }
      return 0;
   }

   return 1;
}

//______________________________________________________________________________
Bool_t TGFALFile::ReadBuffer(char *buf, Int_t len)
{
   // Read specified byte range from remote file via GFAL.
   // Returns kTRUE in case of error.

   Int_t st;
   if ((st = ReadBufferViaCache(buf, len))) {
      if (st == 2)
         return kTRUE;
      return kFALSE;
   }

   return TFile::ReadBuffer(buf, len);
}

//______________________________________________________________________________
Bool_t TGFALFile::WriteBuffer(const char *buf, Int_t len)
{
   // Write specified byte range to remote file via GFAL.
   // Returns kTRUE in case of error.

   if (!IsOpen() || !fWritable) return kTRUE;

   Int_t st;
   if ((st = WriteBufferViaCache(buf, len))) {
      if (st == 2)
         return kTRUE;
      return kFALSE;
   }

   return TFile::WriteBuffer(buf, len);
}


//______________________________________________________________________________
TGFALSystem::TGFALSystem() : TSystem("-gfal", "GFAL Helper System")
{
   // Create helper class that allows directory access via GFAL.

   // name must start with '-' to bypass the TSystem singleton check
   SetName("gfal");

   fDirp = 0;
}

//______________________________________________________________________________
Int_t TGFALSystem::MakeDirectory(const char *dir)
{
   // Make a directory via GFAL.

   TUrl url(dir);

   Int_t ret = ::gfal_mkdir(url.GetFile(), 0755);

   return ret;
}

//______________________________________________________________________________
void *TGFALSystem::OpenDirectory(const char *dir)
{
   // Open a directory via GFAL. Returns an opaque pointer to a dir
   // structure. Returns 0 in case of error.

   if (fDirp) {
      Error("OpenDirectory", "invalid directory pointer (should never happen)");
      fDirp = 0;
   }

   TUrl url(dir);

   struct stat64 finfo;

   if (::gfal_stat64(url.GetFile(), &finfo) < 0)
      return 0;

   if ((finfo.st_mode & S_IFMT) != S_IFDIR)
      return 0;

   fDirp = (void*) ::gfal_opendir(url.GetFile());

   return fDirp;
}

//______________________________________________________________________________
void TGFALSystem::FreeDirectory(void *dirp)
{
   // Free directory via GFAL.

   if (dirp != fDirp) {
      Error("FreeDirectory", "invalid directory pointer (should never happen)");
      return;
   }

   if (dirp)
      ::gfal_closedir((DIR*)dirp);

   fDirp = 0;
}

//______________________________________________________________________________
const char *TGFALSystem::GetDirEntry(void *dirp)
{
   // Get directory entry via GFAL. Returns 0 in case no more entries.

   if (dirp != fDirp) {
      Error("GetDirEntry", "invalid directory pointer (should never happen)");
      return 0;
   }

   struct dirent64 *dp;

   if (dirp) {
      dp = ::gfal_readdir64((DIR*)dirp);
      if (!dp)
         return 0;
      return dp->d_name;
   }
   return 0;
}

//______________________________________________________________________________
Int_t TGFALSystem::GetPathInfo(const char *path, FileStat_t &buf)
{
   // Get info about a file. Info is returned in the form of a FileStat_t
   // structure (see TSystem.h).
   // The function returns 0 in case of success and 1 if the file could
   // not be stat'ed.

   TUrl url(path);

   struct stat64 sbuf;

   if (path && ::gfal_stat64(url.GetFile(), &sbuf) >= 0) {

      buf.fDev    = sbuf.st_dev;
      buf.fIno    = sbuf.st_ino;
      buf.fMode   = sbuf.st_mode;
      buf.fUid    = sbuf.st_uid;
      buf.fGid    = sbuf.st_gid;
      buf.fSize   = sbuf.st_size;
      buf.fMtime  = sbuf.st_mtime;
      buf.fIsLink = kFALSE;

      return 0;
   }
   return 1;
}

//______________________________________________________________________________
Bool_t TGFALSystem::AccessPathName(const char *path, EAccessMode mode)
{
   // Returns FALSE if one can access a file using the specified access mode.
   // Mode is the same as for the Unix access(2) function.
   // Attention, bizarre convention of return value!!

   TUrl url(path);

   if (::gfal_access(url.GetFile(), mode) == 0)
      return kFALSE;

   return kTRUE;
}