fawkes::MutexLocker Class Reference
[Multi-Threading tools, Fawkes Core Library]

Mutex locking helper. More...

#include <core/threading/mutex_locker.h>

List of all members.


Public Member Functions

 MutexLocker (RefPtr< Mutex > mutex, bool initially_lock=true)
 Constructor.
 MutexLocker (Mutex *mutex, bool initially_lock=true)
 Constructor.
 ~MutexLocker ()
 Destructor.
void relock ()
 Lock this mutex, again.
void unlock ()
 Unlock the mutex.

Detailed Description

Mutex locking helper.

This class is a convenience function which can help you prevent a quite a few headaches. Consider the following code. 

 void my_function()
 {
   mutex->lock();
   for (int i = 0; i < LIMIT; ++i) {
     if ( failure ) {
       mutex->unlock
     }
   }
   switch ( someval ) {
     VALA:
       mutex->unlock();
       return;
     VALB:
       do_something();
   }
   try {
     do_function_that_throws_exceptions();
   } catch (Exception &e) {
     mutex->unlock();
     throw;
   }
   mutex->unlock();
 }
This is not a complete list of examples but as you see if you have many exit points in a function it becomes more and more work to have correct locking behavior.

This is a lot simpler with the MutexLocker. The MutexLocker locks the given mutex on creation, and unlocks it in the destructor. If you now have a mutex locker on the stack as integral type the destructor is called automagically on function exit and thus the mutex is appropriately unlocked. The code would look like this: 

 void my_function()
 {
   MutexLocker ml(mutex);
   // do anything, no need to call mutex->lock()/unlock() if only has to be
   // called on entering and exiting the function.
 }

Author:
Tim Niemueller

Definition at line 33 of file mutex_locker.h.

Constructor & Destructor Documentation

fawkes::MutexLocker::MutexLocker ( RefPtr< Mutex >  mutex,
bool  initially_lock = true 
)

Constructor.

Parameters:
mutex Mutex to lock/unlock appropriately.
initially_lock true to lock the mutex in the constructor, false to not lock

Definition at line 90 of file mutex_locker.cpp.

fawkes::MutexLocker::MutexLocker ( Mutex *  mutex,
bool  initially_lock = true 
)

Constructor.

Parameters:
mutex Mutex to lock/unlock appropriately.
initially_lock true to lock the mutex in the constructor, false to not lock

Definition at line 105 of file mutex_locker.cpp.

References fawkes::Mutex::lock().

fawkes::MutexLocker::~MutexLocker (  ) 

Destructor.

Definition at line 116 of file mutex_locker.cpp.

References fawkes::Mutex::unlock().

Member Function Documentation

void fawkes::MutexLocker::relock (  ) 

Lock this mutex, again.

Use this if you unlocked the mutex from the outside.

Definition at line 132 of file mutex_locker.cpp.

References fawkes::Mutex::lock().

void fawkes::MutexLocker::unlock (  ) 

Unlock the mutex.

Definition at line 145 of file mutex_locker.cpp.

References fawkes::Mutex::unlock().

Referenced by fawkes::FawkesNetworkClientRecvThread::recv().

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