SettingScope Class Reference

Makes temporary changes to preferences, then rolls them back at destruction. More...

#include <Prefs.h>

Inheritance diagram for SettingScope:

Collaboration diagram for SettingScope:

Public Types
enum	AddResult { NotAdded , Added , PreviouslyAdded }

Public Member Functions
	SettingScope ()
	~SettingScope () noexcept
	SettingScope (const SettingScope &)=delete
SettingScope &	operator= (const SettingScope &)=delete

Static Public Member Functions
static AddResult	Add (TransactionalSettingBase &setting)

Protected Attributes
std::set< TransactionalSettingBase * >	mPending
bool	mCommitted = false

Detailed Description

Makes temporary changes to preferences, then rolls them back at destruction.

No copy or move.

Definition at line 119 of file Prefs.h.

Member Enumeration Documentation

AddResult

enum SettingScope::AddResult

Returns

NotAdded if there is no pending (and uncommitted) scope; PreviouslyAdded if there is one, but the given setting object was already added since it began; else Added

Enumerator
NotAdded
Added
PreviouslyAdded

Definition at line 133 of file Prefs.h.

{ NotAdded, Added, PreviouslyAdded };

Constructor & Destructor Documentation

SettingScope() [1/2]

SettingScope::SettingScope

(

)

Definition at line 275 of file Prefs.cpp.

{
   sScopes.push_back(this);
}

References anonymous_namespace{Prefs.cpp}::sScopes.

~SettingScope()

SettingScope::~SettingScope ( )

noexcept

Definition at line 280 of file Prefs.cpp.

{
   // Settings can be scoped only on stack
   // so it should be safe to assume that sScopes.top() == this;
   assert(!sScopes.empty() && sScopes.back() == this);
 
   if (sScopes.empty() || sScopes.back() != this)
      return;
 
   if (!mCommitted)
      for (auto pSetting : mPending)
         pSetting->Rollback();
 
   sScopes.pop_back();
}

References anonymous_namespace{Prefs.cpp}::sScopes.

SettingScope() [2/2]

SettingScope::SettingScope ( const SettingScope &  )

delete

Member Function Documentation

Add()

auto SettingScope::Add ( TransactionalSettingBase &  setting )

static

Definition at line 297 of file Prefs.cpp.

{
   if ( sScopes.empty() || sScopes.back()->mCommitted )
      return NotAdded;
 
   const bool inserted = sScopes.back()->mPending.insert(&setting).second;
 
   if (inserted)
   {
      setting.EnterTransaction(sScopes.size());
 
      // We need to introduce this setting into all
      // previous scopes that do not yet contain it.
      for (auto it = sScopes.rbegin() + 1; it != sScopes.rend(); ++it)
      {
         if ((*it)->mPending.find(&setting) != (*it)->mPending.end())
            break;
         
         (*it)->mPending.insert(&setting);
      }
   }
   
   return inserted ? Added : PreviouslyAdded;
}

References anonymous_namespace{Prefs.cpp}::sScopes.

Referenced by Setting< T >::Write().

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operator=()

SettingScope & SettingScope::operator= ( const SettingScope &  )

delete

Member Data Documentation

mCommitted

bool SettingScope::mCommitted = false

protected

Definition at line 138 of file Prefs.h.

mPending

std::set< TransactionalSettingBase * > SettingScope::mPending

protected

Definition at line 137 of file Prefs.h.

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

• Prefs.h
• Prefs.cpp