OSB_LIB::RwGuard Class Reference

Collaboration diagram for OSB_LIB::RwGuard:

Detailed Description

Guard a RwMutex.

A guard is an object that releases a lock, that was aquired by the creator of the guard, when it goes out of scope. The lock ownership is transferred when a guard is copied. On assignment a held lock is unlocked and the ownership is transferred.

This class provides a guard for a RwMutex.

Definition at line 330 of file mutex.h.

Public Types

typedef int(RwMutex::*) Unlock ()
Call a member function of RwMutex to unlock.

Public Member Functions

RwGuard (bool locked=true, RwMutex *pMutex=0, Unlock unlock=0)
Create a RwGuard.
~RwGuard ()
The destructor calls the unlock function if the destructed object owns the lock.
RwGuard (RwGuard &rhs)
Non-const copy constructor, takes the lock ownership from `rhs'.
RwGuard & operator= (RwGuard rhs)
Non-const assignment operator.
void unlock ()
Call the unlock function.
bool locked () const
Lock owned by the current object?
bool release ()
Release lock ownership without unlocking the mutex.

Non-const construction.

The following constructor and conversion operator are used to achive the non-const copy constructor RwGuard(RwGuard) by compiler generated conversions.

RwGuard (RwGuardRef r)
Construct from a RwGuardRef, takes the lock ownership from `r'.
operator RwGuardRef ()
Convert to a RwGuardRef.

Private Attributes

bool locked_
Owner of lock?
RwMutex * pMutex_
Mutex to unlock.
Unlock unlock_
Unlock function to call.

Classes

struct RwGuardRef
Helping structure to allow non-const copy of RwGuard. More...

Member Typedef Documentation

typedef int(RwMutex::*) OSB_LIB::RwGuard::Unlock()

Call a member function of RwMutex to unlock.

Definition at line 345 of file mutex.h.

Constructor & Destructor Documentation

OSB_LIB::RwGuard::RwGuard	(	bool	locked = `true`,
		RwMutex *	pMutex = `0`,
		Unlock	unlock = `0`
	)

Create a RwGuard.

If used as default constructor, i.e. without providing a mutex, the guard should behave as if it was locked. This makes it possible to verify the correct usage of guard with respect to copying and assignment.

Parameters:

	locked	Flag if the caller of the function owns the appropriate lock when the constructor is called (true is yes, false if no).
	pMutex	RwMutex to unlock.
	unlock	Unlock function to call: either RwMutex::readUnlock or RwMutex::writeUnlock.

OSB_LIB::RwGuard::~RwGuard ( )

The destructor calls the unlock function if the destructed object owns the lock.

OSB_LIB::RwGuard::RwGuard ( RwGuard & rhs )

Non-const copy constructor, takes the lock ownership from `rhs'.

OSB_LIB::RwGuard::RwGuard ( RwGuardRef r )

Construct from a RwGuardRef, takes the lock ownership from `r'.

Member Function Documentation

bool OSB_LIB::RwGuard::locked ( ) const [inline]

Lock owned by the current object?

Definition at line 415 of file mutex.h.

References locked_.

Referenced by OSB_LIB::ResourceList< R >::clear(), OSB_LIB::ResourceList< R >::erase(), OSB_LIB::ResourceList< R >::insert(), and OSB_LIB::ResourceList< R >::replace().

OSB_LIB::RwGuard::operator RwGuardRef ( )

Convert to a RwGuardRef.

RwGuard& OSB_LIB::RwGuard::operator= ( RwGuard rhs )

Non-const assignment operator.

The assignment operator first unlocks a held lock and then transfers the lock ownership.

bool OSB_LIB::RwGuard::release ( )

Release lock ownership without unlocking the mutex.

Remarks:: After the function is called, `locked_' is always false and the guard will no more dereference the mutex pointer to call the unlock function.