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/*************************************************
* Mutex Source File *
* (C) 1999-2005 The Botan Project *
*************************************************/
#include <botan/mutex.h>
#include <botan/exceptn.h>
#include <botan/init.h>
namespace Botan {
namespace {
/*************************************************
* Global Mutex Variables *
*************************************************/
Mutex* mutex_factory = 0;
Mutex* mutex_init_lock = 0;
/*************************************************
* Default Mutex *
*************************************************/
class Default_Mutex : public Mutex
{
public:
void lock();
void unlock();
Mutex* clone() const { return new Default_Mutex; }
Default_Mutex() { locked = false; }
private:
bool locked;
};
/*************************************************
* Lock the mutex *
*************************************************/
void Default_Mutex::lock()
{
if(locked)
throw Internal_Error("Default_Mutex::lock: Mutex is already locked");
locked = true;
}
/*************************************************
* Unlock the mutex *
*************************************************/
void Default_Mutex::unlock()
{
if(!locked)
throw Internal_Error("Default_Mutex::unlock: Mutex is already unlocked");
locked = false;
}
}
/*************************************************
* Get a mew mutex *
*************************************************/
Mutex* get_mutex()
{
if(mutex_factory == 0)
return new Default_Mutex;
return mutex_factory->clone();
}
/*************************************************
* Initialize a mutex atomically *
*************************************************/
void initialize_mutex(Mutex*& mutex)
{
if(mutex) return;
if(mutex_init_lock)
{
Mutex_Holder lock(mutex_init_lock);
if(mutex == 0)
mutex = get_mutex();
}
else
mutex = get_mutex();
}
namespace Init {
/*************************************************
* Set the Mutex type *
*************************************************/
void set_mutex_type(Mutex* mutex)
{
delete mutex_factory;
delete mutex_init_lock;
mutex_factory = mutex;
if(mutex) mutex_init_lock = get_mutex();
else mutex_init_lock = 0;
}
}
}
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