RAII for a database transaction, possibly nested. More...

#include <TransactionScope.h>

Collaboration diagram for TransactionScope:

Classes
struct	Factory
	Type of function supplying implementation of steps. More...

Public Member Functions
	TransactionScope (AudacityProject &project, const char *name)
	Construct from a project. More...

	~TransactionScope ()
	Rollback transaction if it was not yet committed. More...

bool	Commit ()
	Commit the transaction. More...

Private Attributes
std::unique_ptr< TransactionScopeImpl >	mpImpl

bool	mInTrans

wxString	mName

Detailed Description

RAII for a database transaction, possibly nested.

Make a savepoint (a transaction, possibly nested) with the given name; roll it back at destruction time, unless an explicit Commit() happened first. Commit() must not be called again after one successful call. An exception is thrown from the constructor if the transaction cannot open.

Definition at line 27 of file TransactionScope.h.

Constructor & Destructor Documentation

◆ TransactionScope()

TransactionScope::TransactionScope	(	AudacityProject &	project,
		const char *	name
	)

Construct from a project.

If no implementation factory is installed, or the factory returns null, then this object does nothing

Definition at line 17 of file TransactionScope.cpp.

:  mName(name)
{
   mpImpl = Factory::Call(project);
   if (!mpImpl)
      return;
 
   mInTrans = mpImpl->TransactionStart(mName);
   if ( !mInTrans )
      // To do, improve the message
      throw SimpleMessageBoxException( ExceptionType::Internal,
         XO("Database error.  Sorry, but we don't have more details."), 
         XO("Warning"), 
         "Error:_Disk_full_or_not_writable"
      );
}

References GlobalHook< Factory, std::unique_ptr< TransactionScopeImpl >(AudacityProject &) >::Call(), Internal, mInTrans, mName, mpImpl, project, and XO().

Here is the call graph for this function:

◆ ~TransactionScope()

TransactionScope::~TransactionScope ( )

Rollback transaction if it was not yet committed.

Definition at line 35 of file TransactionScope.cpp.

{
   if (mpImpl && mInTrans)
   {
      if (!mpImpl->TransactionRollback(mName))
      {
         // Do not throw from a destructor!
         // This has to be a no-fail cleanup that does the best that it can.
         wxLogMessage("Transaction active at scope destruction");
      }
   }
}

References mInTrans, mName, and mpImpl.

Member Function Documentation

◆ Commit()

bool TransactionScope::Commit ( )

Commit the transaction.

Definition at line 48 of file TransactionScope.cpp.

{
   if (mpImpl && !mInTrans) {
      wxLogMessage("No active transaction to commit");
      // Misuse of this class
      THROW_INCONSISTENCY_EXCEPTION;
   }
 
   // If commit is unsuccessful, consider us still in a commit, for the dtor
   // later
   mInTrans = !mpImpl->TransactionCommit(mName);
 
   return !mInTrans;
}