TDirectory::TContext Class Reference

TDirectory::TContext keeps track and restore the current directory.

With this tool C++ exceptions will be guaranteed to properly restore the current directory pointer.

For example code like:

TDirectory *sav = gDirectory;
mydirectory->cd();
if (...) {
   ....
   sav->cd();
   return;
} else if (...) {
   ....
   sav->cd();
   return;
}
sav->cd;
return;

can be replaced with the simpler and exception safe:

TDirectory::TContext context(gDirectory, mydirectory);
if (...) {
   ....
   return;
} else if (...) {
   ....
   return;
}
return;

Definition at line 89 of file TDirectory.h.

Public Member Functions
	TContext ()
	TContext (TDirectory *newCurrent)
	TContext (TDirectory *previous, TDirectory *newCurrent)
	~TContext ()
	Destructor.

Private Member Functions
	TContext (TContext &)=delete
	Pointer to the next TContext in the implied list of context pointing to fPrevious.
void	CdNull ()
	Set the current directory to null.
TContext &	operator= (TContext &)=delete
void	RegisterCurrentDirectory ()

Private Attributes
std::atomic< bool >	fActiveDestructor {false}
	Pointer to the previous current directory.
std::atomic< TDirectory * >	fDirectory {nullptr}
std::atomic< bool >	fDirectoryWait {false}
	Set to true during the destructor execution.
TContext *	fNext {nullptr}
	Pointer to the next TContext in the implied list of context pointing to fPrevious.
TContext *	fPrevious {nullptr}
	Set to true if a TDirectory might still access this object.

Friends
class	TDirectory

#include <TDirectory.h>

Constructor & Destructor Documentation

TContext() [1/4]

TDirectory::TContext::TContext ( TContext &  )

privatedelete

Pointer to the next TContext in the implied list of context pointing to fPrevious.

TContext() [2/4]

TDirectory::TContext::TContext ( TDirectory *  previous, TDirectory *  newCurrent  )

inline

Definition at line 108 of file TDirectory.h.

TContext() [3/4]

TDirectory::TContext::TContext ( )

inline

Definition at line 120 of file TDirectory.h.

TContext() [4/4]

TDirectory::TContext::TContext ( TDirectory *  newCurrent )

inline

Definition at line 126 of file TDirectory.h.

~TContext()

TDirectory::TContext::~TContext

(

)

Destructor.

Reset the current directory to its previous state.

Definition at line 141 of file TDirectory.cxx.

Member Function Documentation

CdNull()

void TDirectory::TContext::CdNull ( )

private

Set the current directory to null.

This is called from the TContext destructor. Since the destructor is inline, we do not want to have it directly use a global variable.

Definition at line 131 of file TDirectory.cxx.

operator=()

TContext & TDirectory::TContext::operator= ( TContext &  )

privatedelete

RegisterCurrentDirectory()

void TDirectory::TContext::RegisterCurrentDirectory ( )

private

Definition at line 1349 of file TDirectory.cxx.

Friends And Related Symbol Documentation

TDirectory

friend class TDirectory

friend

Definition at line 101 of file TDirectory.h.

Member Data Documentation

fActiveDestructor

std::atomic<bool> TDirectory::TContext::fActiveDestructor {false}

private

Pointer to the previous current directory.

Definition at line 92 of file TDirectory.h.

fDirectory

std::atomic<TDirectory*> TDirectory::TContext::fDirectory {nullptr}

private

Definition at line 91 of file TDirectory.h.

fDirectoryWait

std::atomic<bool> TDirectory::TContext::fDirectoryWait {false}

private

Set to true during the destructor execution.

Definition at line 93 of file TDirectory.h.

fNext

TContext* TDirectory::TContext::fNext {nullptr}

private

Pointer to the next TContext in the implied list of context pointing to fPrevious.

Definition at line 95 of file TDirectory.h.

fPrevious

TContext* TDirectory::TContext::fPrevious {nullptr}

private

Set to true if a TDirectory might still access this object.

Definition at line 94 of file TDirectory.h.