TStorageFactoryFile Class Reference

#include <TStorageFactoryFile.h>

Inherits ROOT::TFile.

List of all members.

Public Member Functions
	ClassDef (TStorageFactoryFile, 0)
virtual Bool_t	ReadBuffer (char *buf, Int_t len)
virtual Bool_t	ReadBuffer (char *buf, Long64_t pos, Int_t len)
virtual Bool_t	ReadBufferAsync (Long64_t off, Int_t len)
virtual Bool_t	ReadBuffers (char *buf, Long64_t *pos, Int_t *len, Int_t nbuf)
void	ResetErrno (void) const
	TStorageFactoryFile (const char *name, Option_t *option="", const char *ftitle="", Int_t compress=1)
virtual Bool_t	WriteBuffer (const char *buf, Int_t len)
	~TStorageFactoryFile (void)
Protected Member Functions
virtual Int_t	SysClose (Int_t fd)
virtual Int_t	SysOpen (const char *pathname, Int_t flags, UInt_t mode)
virtual Long64_t	SysSeek (Int_t fd, Long64_t offset, Int_t whence)
virtual Int_t	SysStat (Int_t fd, Long_t *id, Long64_t *size, Long_t *flags, Long_t *modtime)
virtual Int_t	SysSync (Int_t fd)
Private Member Functions
	TStorageFactoryFile (void)
Private Attributes
Storage *	storage_

---

Detailed Description

TFile wrapper around StorageFactory and Storage.

Definition at line 11 of file TStorageFactoryFile.h.

---

Constructor & Destructor Documentation

TStorageFactoryFile::TStorageFactoryFile	(	const char *	name,
		Option_t *	option = "",
		const char *	ftitle = "",
		Int_t	compress = 1
	)

Definition at line 97 of file TStorageFactoryFile.cc.

References SurfaceDeformationFactory::create(), Exception, StorageFactory::get(), IOFlags::OpenCreate, IOFlags::OpenRead, IOFlags::OpenTruncate, IOFlags::OpenWrite, path(), SiPixelLorentzAngle_cfi::read, storage_, storageCounter(), StorageAccount::Stamp::tick(), and update.

  : TFile(path, "NET", ftitle, compress), // Pass "NET" to prevent local access in base class
    storage_(0)
{
  StorageAccount::Stamp stats(storageCounter(s_statsCtor, "construct"));

  // Parse options; at the moment we only accept read!
  fOption = option;
  fOption.ToUpper();

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

  Bool_t create   = (fOption == "CREATE");
  Bool_t recreate = (fOption == "RECREATE");
  Bool_t update   = (fOption == "UPDATE");
  Bool_t read     = (fOption == "READ");

  if (!create && !recreate && !update && !read)
  {
    read = true;
    fOption = "READ";
  }

  if (recreate)
  {
    if (!gSystem->AccessPathName(path, kFileExists))
      gSystem->Unlink(path);

    recreate = false;
    create   = true;
    fOption  = "CREATE";
  }

  if (update && gSystem->AccessPathName(path, kFileExists))
  {
    update = kFALSE;
    create = kTRUE;
  }

  int           openFlags = IOFlags::OpenRead;
  if (!read)    openFlags |= IOFlags::OpenWrite;
  if (create)   openFlags |= IOFlags::OpenCreate;
  if (recreate) openFlags |= IOFlags::OpenCreate | IOFlags::OpenTruncate;

  // Open storage
  if (! (storage_ = StorageFactory::get()->open(path, openFlags)))
  {
     MakeZombie();
     gDirectory = gROOT;
     throw cms::Exception("TStorageFactoryFile::TStorageFactoryFile()")
       << "Cannot open file '" << path << "'";
  }

  fRealName = path;
  fD = 0; // sorry, meaningless
  fWritable = read ? kFALSE : kTRUE;

  Init(create);

  stats.tick(0);
}

TStorageFactoryFile::~TStorageFactoryFile

(

void

)

Definition at line 163 of file TStorageFactoryFile.cc.

References storage_.

{
  Close();
  delete storage_;
}

TStorageFactoryFile::TStorageFactoryFile

(

void

)

[private]

Definition at line 89 of file TStorageFactoryFile.cc.

References storageCounter(), and StorageAccount::Stamp::tick().

  : storage_(0)
{
  StorageAccount::Stamp stats(storageCounter(s_statsCtor, "construct"));
  stats.tick(0);
}

---

Member Function Documentation

TStorageFactoryFile::ClassDef	(	TStorageFactoryFile	,
		0
	)

Bool_t TStorageFactoryFile::ReadBuffer	(	char *	buf,
		Int_t	len
	)		[virtual]

Definition at line 183 of file TStorageFactoryFile.cc.

References trackerHits::c, n, s_statsCPrefetch, s_statsCRead, s_statsRead, s_statsXRead, storage_, storageCounter(), StorageAccount::Stamp::tick(), and IOInput::xread().

Referenced by ReadBuffer().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("ReadBuffer", "Cannot read from a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("ReadBuffer", "Cannot read from a file that is not open");
    return kTRUE;
  }

  // Read specified byte range from the storage.  Returns kTRUE in
  // case of error.  Note that ROOT uses this function recursively
  // to fill the cache; we use a flag to make sure our accounting
  // is reflected in a comprehensible manner.  The "read" counter
  // will include both, "readc" indicates how much read from the
  // cache, "readu" indicates how much we failed to read from the
  // cache (excluding those recursive reads), and "readx" counts
  // the amount actually passed to read from the storage object.
  StorageAccount::Stamp stats(storageCounter(s_statsRead, "read"));

  // If we have a cache, read from there first.  This returns 0
  // if the block hasn't been prefetched, 1 if it was in cache,
  // and 2 if there was an error.
  if (TFileCacheRead *c = GetCacheRead())
  {
    Long64_t here = GetRelOffset();
    Bool_t   async = c->IsAsyncReading();

    StorageAccount::Stamp cstats(async
                                 ? storageCounter(s_statsCPrefetch, "readPrefetchToCache")
                                 : storageCounter(s_statsCRead, "readViaCache"));

    Int_t st = ReadBufferViaCache(async ? 0 : buf, len);

    if (st == 2) {
      return kTRUE;
    }

    if (st == 1) {
      if (async) {
        cstats.tick(len);
        Seek(here);
      } else {
        cstats.tick(len);
        stats.tick(len);
        return kFALSE;
      }
    }
  }

  // FIXME: Re-enable read-ahead if the data wasn't in cache.
  // if (! st) storage_->caching(true, -1, s_readahead);

  // A real read
  StorageAccount::Stamp xstats(storageCounter(s_statsXRead, "readActual"));
  IOSize n = storage_->xread(buf, len);
  xstats.tick(n);
  stats.tick(n);
  return n ? kFALSE : kTRUE;
}

Bool_t TStorageFactoryFile::ReadBuffer	(	char *	buf,
		Long64_t	pos,
		Int_t	len
	)		[virtual]

Definition at line 174 of file TStorageFactoryFile.cc.

References ReadBuffer().

{
  // This function needs to be optimized to minimize seeks.
  // See TFile::ReadBuffer(char *buf, Long64_t pos, Int_t len) in ROOT 5.27.06.
  Seek(pos);
  return ReadBuffer(buf, len);
}

Bool_t TStorageFactoryFile::ReadBufferAsync	(	Long64_t	off,
		Int_t	len
	)		[virtual]

Definition at line 250 of file TStorageFactoryFile.cc.

References StorageFactory::CACHE_HINT_APPLICATION, StorageFactory::CACHE_HINT_STORAGE, StorageFactory::cacheHint(), f, reco::get(), o2o::iov, Storage::prefetch(), s_statsARead, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("ReadBufferAsync", "Cannot read from a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("ReadBufferAsync", "Cannot read from a file that is not open");
    return kTRUE;
  }

  StorageAccount::Stamp stats(storageCounter(s_statsARead, "readAsync"));

  // If asynchronous reading is disabled, bail out now, regardless
  // whether the underlying storage supports prefetching.  If it is
  // forced on, pretend it's on, even if the storage doesn't support
  // it, as this turns off the caching in ROOT's side.
  StorageFactory *f = StorageFactory::get();

  // Verify that we never using async reads in app-only mode
  if (f->cacheHint() == StorageFactory::CACHE_HINT_APPLICATION)
    return kTRUE;

  // Let the I/O method indicate if it can do client-side prefetch.
  // If it does, then for example TTreeCache will drop its own cache
  // and will use the client-side cache of the actual I/O layer.
  // If len is zero ROOT is probing for prefetch support.
  if (len) {
    // FIXME: Synchronise caching.
    // storage_->caching(true, -1, 0);
    ;
  }

  IOPosBuffer iov(off, (void *) 0, len ? len : 4096);
  if (storage_->prefetch(&iov, 1))
  {
    stats.tick(len);
    return kFALSE;
  }

  // Always ask ROOT to use async reads in storage-only mode,
  // regardless of whether the storage system supports it.
  if (f->cacheHint() == StorageFactory::CACHE_HINT_STORAGE)
    return kFALSE;

  // Prefetching not available right now.
  return kTRUE;
}

Bool_t TStorageFactoryFile::ReadBuffers	(	char *	buf,
		Long64_t *	pos,
		Int_t *	len,
		Int_t	nbuf
	)		[virtual]

Definition at line 304 of file TStorageFactoryFile.cc.

References i, IOSized(), o2o::iov, j, gen::k, n, Storage::prefetch(), READ_COALESCE_SIZE, query::result, s_statsARead, s_statsXRead, storage_, storageCounter(), summarizeEdmComparisonLogfiles::success, StorageAccount::Stamp::tick(), pileupDistInMC::total, and IOInput::xread().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("ReadBuffers", "Cannot read from a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("ReadBuffers", "Cannot read from a file that is not open");
    return kTRUE;
  }

  // This should coalesce reads into a smaller number of large reads.
  // If the list of buffers to read has two or more buffers within 256KB of
  // each other, we collapse them into a single read from the storage system.

  // buf == 0 implies an async read; in this case, we skip the read coalescing logic.
  // Note that this code will cause CMSSW to never call readv().
  if (buf)
  {
    // Code ported from ROOT v5.26 trunk by Brian Bockelman.
    Int_t k = 0;
    Bool_t result = kTRUE;
    TFileCacheRead *old = fCacheRead;
    fCacheRead = 0;
    IOOffset curbegin = pos[0];
    IOOffset cur;
    std::vector<char> buf2(0);
    Int_t i = 0; // Position in the buffer.
    Int_t n = 0; // Number of reads we have coalesced.

    // Size of our coalesce window.  In ROOT 5.26, this is actually a variable
    // you can tweak, but it's not exposed in CMSSW.

    // Iterate over all the requests we have been given.  We either read each
    // individually or coalesce them into a big read.

    // Loop over all the requests we have been given.  Only trigger a read if the
    // request at pos[i] wouldn't completely fit into the read coalesce buffer.
    // If we trigger, then we do a single read for requests i-n to i-1, inclusive.
    // If n==0, we have special logic.
    while (i < nbuf)
    {
      cur = pos[i]+len[i];
      Bool_t bigRead = kTRUE;
      if (cur -curbegin < READ_COALESCE_SIZE)
      {
        // Add the current request into the set of buffers we will coalesce
        n++; // Record we have a new request we will coalesce.
        i++; // Examine the next request in the next loop.
        bigRead = kFALSE;
      }
      // Only perform a read if one of the following holds:
      // 1) bigRead=TRUE; i.e., we can't fit any more requests into the window.
      // 2) i>=nbuf; if i pointed to nbuf-1 at the beginning of the while loop,
      //    then the above logic will either set bigRead=TRUE (making case #1
      //    true) or increment i, making i == nbuf.
      if (bigRead || (i>=nbuf))
      {
        // If n == 0, no read requests could be coalesced.  Simple read.
        if (n == 0)
        {
          //if the block to read is about the same size as the read-ahead buffer
          //we read the block directly
          Seek(pos[i]);

          StorageAccount::Stamp xstats(storageCounter(s_statsXRead, "readActual"));
          // if xread returns short, then we have an error.  Break from the loop
          // and return kTRUE - signaling an error.
          result = ((IOSize)len[i] == storage_->xread(&buf[k], len[i])) ? kFALSE : kTRUE;
          xstats.tick(len[i]);
             
          if (result)
            break;
          k += len[i];
          i++;
        }
        else
        {
          //otherwise we read all blocks that fit in the read-ahead buffer
          Seek(curbegin);
          // Only allocate buf2 once; use std::vector to make sure the memory
          // gets cleaned up, as xread can toss an exception.
          if (buf2.capacity() < READ_COALESCE_SIZE)
            buf2.resize(READ_COALESCE_SIZE);
          //we read ahead
          assert(len[i-1] >= 0);
          assert(pos[i-1] >= curbegin);
          assert(pos[i-1]-curbegin+len[i-1] <= READ_COALESCE_SIZE);
          IOSize nahead = IOSized(pos[i-1]-curbegin+len[i-1]);

          StorageAccount::Stamp xstats(storageCounter(s_statsXRead, "readActual"));
          result = ( nahead == storage_->xread(&buf2[0], nahead)) ? kFALSE : kTRUE;
          xstats.tick(nahead);

          if (result)
            break;

          // Now, copy the data from the read to the appropriate buffer in
          // order to fulfill the request.
          for (Int_t j=0;j<n;j++) {
                memcpy(&buf[k],&buf2[pos[i-n+j]-curbegin],len[i-n+j]);
                k += len[i-n+j];
          }
          n = 0;
        }
        curbegin = pos[i];
      }
    }
    fCacheRead = old;
    return result;
  }

  // Read from underlying storage.
  Int_t total = 0;
  std::vector<IOPosBuffer> iov;
  iov.reserve(nbuf);
  for (Int_t i = 0; i < nbuf; ++i)
  {
    iov.push_back(IOPosBuffer(pos[i], buf ? buf + total : 0, len[i]));
    total += len[i];
  }

  // Null buffer means asynchronous reads into I/O system's cache.
  bool success;
  StorageAccount::Stamp astats(storageCounter(s_statsARead, "readAsync"));
  // Synchronise low-level cache with the supposed cache in TFile.
  // storage_->caching(true, -1, 0);
  success = storage_->prefetch(&iov[0], nbuf);
  astats.tick(total);

  // If it didn't suceeed, pass down to the base class.
  return success ? kFALSE : TFile::ReadBuffers(buf, pos, len, nbuf);
}

void TStorageFactoryFile::ResetErrno

(

void

)

const

Definition at line 591 of file TStorageFactoryFile.cc.

{
  TSystem::ResetErrno();
}

Int_t TStorageFactoryFile::SysClose

(

Int_t

fd

)

[protected, virtual]

Definition at line 539 of file TStorageFactoryFile.cc.

References Storage::close(), s_statsClose, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsClose, "close"));

  if (storage_)
  {
    storage_->close();
    delete storage_;
    storage_ = 0;
  }

  stats.tick();
  return 0;
}

Int_t TStorageFactoryFile::SysOpen	(	const char *	pathname,
		Int_t	flags,
		UInt_t	mode
	)		[protected, virtual]

Definition at line 506 of file TStorageFactoryFile.cc.

References Storage::close(), Exception, StorageFactory::get(), O_NONBLOCK, IOFlags::OpenAppend, IOFlags::OpenCreate, IOFlags::OpenExclusive, IOFlags::OpenNonBlock, IOFlags::OpenRead, IOFlags::OpenTruncate, IOFlags::OpenWrite, s_statsOpen, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsOpen, "open"));

  if (storage_)
  {
    storage_->close();
    delete storage_;
    storage_ = 0;
  }

  int                      openFlags = IOFlags::OpenRead;
  if (flags & O_WRONLY)    openFlags = IOFlags::OpenWrite;
  else if (flags & O_RDWR) openFlags |= IOFlags::OpenWrite;
  if (flags & O_CREAT)     openFlags |= IOFlags::OpenCreate;
  if (flags & O_APPEND)    openFlags |= IOFlags::OpenAppend;
  if (flags & O_EXCL)      openFlags |= IOFlags::OpenExclusive;
  if (flags & O_TRUNC)     openFlags |= IOFlags::OpenTruncate;
  if (flags & O_NONBLOCK)  openFlags |= IOFlags::OpenNonBlock;

  if (! (storage_ = StorageFactory::get()->open(pathname, openFlags)))
  {
     MakeZombie();
     gDirectory = gROOT;
     throw cms::Exception("TStorageFactoryFile::SysOpen()")
       << "Cannot open file '" << pathname << "'";
  }

  stats.tick();
  return 0;
}

Long64_t TStorageFactoryFile::SysSeek	(	Int_t	fd,
		Long64_t	offset,
		Int_t	whence
	)		[protected, virtual]

Definition at line 555 of file TStorageFactoryFile.cc.

References Storage::CURRENT, Storage::END, evf::evtn::offset(), Storage::position(), s_statsSeek, Storage::SET, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsSeek, "seek"));
  Storage::Relative rel = (whence == SEEK_SET ? Storage::SET
                           : whence == SEEK_CUR ? Storage::CURRENT
                           : Storage::END);

  offset = storage_->position(offset, rel);
  stats.tick();
  return offset;
}

Int_t TStorageFactoryFile::SysStat	(	Int_t	fd,
		Long_t *	id,
		Long64_t *	size,
		Long_t *	flags,
		Long_t *	modtime
	)		[protected, virtual]

Definition at line 577 of file TStorageFactoryFile.cc.

References s_statsStat, Storage::size(), storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsStat, "stat"));
  // FIXME: Most of this is unsupported or makes no sense with Storage
  *id = ::Hash(fRealName);
  *size = storage_->size();
  *flags = 0;
  *modtime = 0;
  stats.tick();
  return 0;
}

Int_t TStorageFactoryFile::SysSync

(

Int_t

fd

)

[protected, virtual]

Definition at line 568 of file TStorageFactoryFile.cc.

References Storage::flush(), s_statsFlush, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsFlush, "flush"));
  storage_->flush();
  stats.tick();
  return 0;
}

Bool_t TStorageFactoryFile::WriteBuffer	(	const char *	buf,
		Int_t	len
	)		[virtual]

Definition at line 443 of file TStorageFactoryFile.cc.

References n, s_statsCWrite, s_statsWrite, s_statsXWrite, storage_, storageCounter(), StorageAccount::Stamp::tick(), and IOOutput::xwrite().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("WriteBuffer", "Cannot write to a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("WriteBuffer", "Cannot write to a file that is not open");
    return kTRUE;
  }

  if (! fWritable)
  {
    Error("WriteBuffer", "File is not writable");
    return kTRUE;
  }

  StorageAccount::Stamp stats(storageCounter(s_statsWrite, "write"));
  StorageAccount::Stamp cstats(storageCounter(s_statsCWrite, "writeViaCache"));

  // Try first writing via a cache, and if that's not possible, directly.
  Int_t st;
  switch ((st = WriteBufferViaCache(buf, len)))
  {
  case 0:
    // Actual write.
    {
      StorageAccount::Stamp xstats(storageCounter(s_statsXWrite, "writeActual"));
      IOSize n = storage_->xwrite(buf, len);
      xstats.tick(n);
      stats.tick(n);

      // FIXME: What if it's a short write?
      return n > 0 ? kFALSE : kTRUE;
    }

  case 1:
    cstats.tick(len);
    stats.tick(len);
    return kFALSE;

  case 2:
  default:
    Error("WriteBuffer", "Error writing to cache");
    return kTRUE;
  }
}

---

Member Data Documentation

Storage* TStorageFactoryFile::storage_ [private]

Definition at line 38 of file TStorageFactoryFile.h.

Referenced by ReadBuffer(), ReadBufferAsync(), ReadBuffers(), SysClose(), SysOpen(), SysSeek(), SysStat(), SysSync(), TStorageFactoryFile(), WriteBuffer(), and ~TStorageFactoryFile().