XrdCl::StreamMutex Class Reference

#include <XrdClStream.hh>

Collaboration diagram for XrdCl::StreamMutex:

Classes
struct	MtxInfo

Public Member Functions
	StreamMutex ()
	~StreamMutex ()
void	AddClosing (uint16_t subStream)
	AddClosing. Notified that subStream will be closed. More...
void	Lock ()
	Lock. Regular, non-subStream aware recursive lock. More...
void	Lock (const std::function< void()> &func, bool &isclosing)
void	Lock (uint16_t subStream, bool &isclosing)
	Lock. subStream number aware with the potential to abort. More...
void	RemoveClosing (uint16_t subStream)
	RemoveClosing. Notified that subStream close has completed. More...
void	UnLock ()
	UnLock. More...

Public Attributes
std::list< MtxInfo >::iterator	fnlistit
bool	hasfn
std::map< uint16_t, size_t >	mclosing
XrdSysCondVar	mcv
std::list< MtxInfo >	mlist
std::map< pthread_t, std::list< MtxInfo >::iterator >	mthmap

Detailed Description

StreamMutex

Mutex for the main Stream mutex. In the usual case acts as a recursive mutex. But supports an awareness of subStream number. In case an AsyncSocketHandler needs to be Close() any Poller callback must for the handler must complete. (Unless the close is executed within the callback thread). Thus this mutex allows aborting an acquisition attempt when the lock has been declared to be within a subStream callback and when Mutex is notified of an intent to Close that subStream.

Definition at line 61 of file XrdClStream.hh.

Constructor & Destructor Documentation

StreamMutex()

XrdCl::StreamMutex::StreamMutex ( )

inline

Definition at line 64 of file XrdClStream.hh.

: mcv(0), hasfn(false) { }

~StreamMutex()

XrdCl::StreamMutex::~StreamMutex ( )

inline

Definition at line 65 of file XrdClStream.hh.

      {
        assert( mlist.empty() );
        assert( mclosing.empty() );
        assert( mthmap.empty() );
        assert( hasfn == false );
      }

References hasfn, mclosing, mlist, and mthmap.

Member Function Documentation

AddClosing()

void XrdCl::StreamMutex::AddClosing

(

uint16_t

subStream

)

AddClosing. Notified that subStream will be closed.

Definition at line 98 of file XrdClStream.cc.

  {
    XrdSysCondVarHelper lck( mcv );
    mclosing[subStream]++;
    mcv.Broadcast();
  }

References XrdSysCondVar::Broadcast(), mclosing, and mcv.

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Lock() [1/3]

void XrdCl::StreamMutex::Lock

(

)

Lock. Regular, non-subStream aware recursive lock.

Definition at line 119 of file XrdClStream.cc.

  {
    XrdSysCondVarHelper lck( mcv );
    if( mlist.empty() )
    {
      mlist.emplace_front();
      ++mlist.front().cnt;
      mthmap[XrdSysThread::ID()] = mlist.begin();
      return;
    }
    while( 1 )
    {
      auto mit = mthmap.find( XrdSysThread::ID() );
      if( mit == mthmap.end() )
      {
        mlist.emplace_back();
        bool ins;
        std::tie( mit, ins ) = mthmap.insert(
          std::make_pair( XrdSysThread::ID(), std::prev( mlist.end() ) ) );
      }
      if( mit->second == mlist.begin() )
      {
        ++mlist.front().cnt;
        return;
      }
      mcv.Wait();
    }
  }

References XrdSysThread::ID(), mcv, mlist, mthmap, and XrdSysCondVar::Wait().

Referenced by XrdCl::StreamMutexHelper::StreamMutexHelper().

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Lock() [2/3]

void XrdCl::StreamMutex::Lock	(	const std::function< void()> &	func,
		bool &	isclosing
	)

Lock. Locks or otherwise returns immedately, while the Mutex will abort all waiting subStream acquisitions and execute supplied func when lock is released. Lock will be atomically acquired at last release. Only one func may be registered at a time.

Definition at line 195 of file XrdClStream.cc.

  {
    isclosing = false;
    XrdSysCondVarHelper lck( mcv );
    if( mlist.empty() )
    {
      mlist.emplace_front( func );
      ++mlist.front().cnt;
      auto lit = mlist.begin();
      mthmap[XrdSysThread::ID()] = lit;
      fnlistit = lit;
      hasfn = true;
      return;
    }
    while( 1 )
    {
      auto mit = mthmap.find( XrdSysThread::ID() );
      if( mit == mthmap.end() )
      {
        if( hasfn )
        {
          isclosing = true;
          return;
        }
        mlist.emplace_back( func );
        hasfn = true;
        fnlistit = std::prev( mlist.end() );
        mcv.Broadcast();
        isclosing = true;
        return;
      }
      if( mit->second == mlist.begin() )
      {
        ++mlist.front().cnt;
        return;
      }
      mcv.Wait();
    }
  }

References XrdSysCondVar::Broadcast(), fnlistit, hasfn, XrdSysThread::ID(), mcv, mlist, mthmap, and XrdSysCondVar::Wait().

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Lock() [3/3]

void XrdCl::StreamMutex::Lock	(	uint16_t	subStream,
		bool &	isclosing
	)

Lock. subStream number aware with the potential to abort.

Definition at line 152 of file XrdClStream.cc.

  {
    isclosing = false;
    XrdSysCondVarHelper lck( mcv );
    if( mlist.empty() ) {
      mlist.emplace_front();
      ++mlist.front().cnt;
      mthmap[XrdSysThread::ID()] = mlist.begin();
      return;
    }
    while( 1 )
    {
      auto mit = mthmap.find( XrdSysThread::ID() );
      if( mit == mthmap.end() )
      {
        mlist.emplace_back();
        bool ins;
        std::tie( mit, ins ) = mthmap.insert(
          std::make_pair( XrdSysThread::ID(), std::prev( mlist.end() ) ) );
      }
      if( mit->second == mlist.begin() )
      {
        ++mlist.front().cnt;
        return;
      }
      if( hasfn || mclosing.count( subStream ) )
      {
        isclosing = true;
        mlist.erase( mit->second );
        mthmap.erase( mit );
        return;
      }
      mcv.Wait();
    }
  }

References hasfn, XrdSysThread::ID(), mclosing, mcv, mlist, mthmap, and XrdSysCondVar::Wait().

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RemoveClosing()

void XrdCl::StreamMutex::RemoveClosing

(

uint16_t

subStream

)

RemoveClosing. Notified that subStream close has completed.

Definition at line 108 of file XrdClStream.cc.

  {
    XrdSysCondVarHelper lck( mcv );
    mclosing[subStream]--;
    if( mclosing[subStream]==0 ) mclosing.erase( subStream );
    mcv.Broadcast();
  }

References XrdSysCondVar::Broadcast(), mclosing, and mcv.

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UnLock()

void XrdCl::StreamMutex::UnLock

(

)

UnLock.

Definition at line 238 of file XrdClStream.cc.

  {
    // keep any fn callback until return in case it holds a ref count
    std::function<void()> keepfn;
 
    XrdSysCondVarHelper lck( mcv );
    auto mit = mthmap.find( XrdSysThread::ID() );
    if( mit == mthmap.end() ) return;
 
    // we must have held the lock
    assert( mit->second == mlist.begin() );
 
    const size_t cnt = --mlist.front().cnt;
    if( cnt ) return;
 
    if( hasfn && fnlistit == mit->second )
    {
      hasfn = false;
      std::swap( keepfn, mlist.front().fn );
    }
 
    mlist.erase( mit->second );
    mthmap.erase( mit );
 
    // next up should have zero count
    assert( mlist.empty() || mlist.front().cnt == 0 );
 
    if( hasfn && fnlistit == mlist.begin() )
    {
      auto &lfn = mlist.front().fn;
      ++mlist.front().cnt;
      mthmap[XrdSysThread::ID()] = mlist.begin();
      lck.UnLock();
      lfn();
      UnLock();
      return;
    }
    mcv.Broadcast();
  }

References XrdSysCondVar::Broadcast(), fnlistit, hasfn, XrdSysThread::ID(), mcv, mlist, mthmap, swap(), and XrdSysCondVarHelper::UnLock().

Referenced by XrdCl::StreamMutexHelper::UnLock().

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Member Data Documentation

fnlistit

std::list<MtxInfo>::iterator XrdCl::StreamMutex::fnlistit

Definition at line 121 of file XrdClStream.hh.

Referenced by Lock(), and UnLock().

hasfn

bool XrdCl::StreamMutex::hasfn

Definition at line 120 of file XrdClStream.hh.

Referenced by ~StreamMutex(), Lock(), and UnLock().

mclosing

std::map<uint16_t, size_t> XrdCl::StreamMutex::mclosing

Definition at line 118 of file XrdClStream.hh.

Referenced by ~StreamMutex(), AddClosing(), Lock(), and RemoveClosing().

mcv

XrdSysCondVar XrdCl::StreamMutex::mcv

Definition at line 116 of file XrdClStream.hh.

Referenced by AddClosing(), Lock(), RemoveClosing(), and UnLock().

mlist

std::list<MtxInfo> XrdCl::StreamMutex::mlist

Definition at line 117 of file XrdClStream.hh.

Referenced by ~StreamMutex(), Lock(), and UnLock().

mthmap

std::map<pthread_t, std::list<MtxInfo>::iterator> XrdCl::StreamMutex::mthmap

Definition at line 119 of file XrdClStream.hh.

Referenced by ~StreamMutex(), Lock(), and UnLock().

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

• XrdClStream.hh
• XrdClStream.cc