genode/repos/base/include/base/cancelable_lock.h
Norman Feske fd401bdf53 Thread API cleanup
This patch cleans up the thread API and comes with the following
noteworthy changes:

- Introduced Cpu_session::Weight type that replaces a formerly used
  plain integer value to prevent the accidental mix-up of
  arguments.
- The enum definition of Cpu_session::DEFAULT_WEIGHT moved to
  Cpu_session::Weight::DEFAULT_WEIGHT
- New Thread constructor that takes a 'Env &' as first argument.
  The original constructors are now marked as deprecated. For the
  common use case where the default 'Weight' and 'Affinity' are
  used, a shortcut is provided. In the long term, those two
  constructors should be the only ones to remain.
- The former 'Thread<>' class template has been renamed to
  'Thread_deprecated'.
- The former 'Thread_base' class is now called 'Thread'.
- The new 'name()' accessor returns the thread's name as 'Name'
  object as centrally defined via 'Cpu_session::Name'. It is meant to
  replace the old-fashioned 'name' method that takes a buffer and size
  as arguments.
- Adaptation of the thread test to the new API

Issue #1954
2016-05-23 15:49:55 +02:00

98 lines
1.8 KiB
C++

/*
* \brief Basic locking primitive
* \author Norman Feske
* \date 2006-07-26
*/
/*
* Copyright (C) 2006-2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__BASE__CANCELABLE_LOCK_H_
#define _INCLUDE__BASE__CANCELABLE_LOCK_H_
#include <base/lock_guard.h>
#include <base/blocking.h>
namespace Genode {
class Thread;
class Cancelable_lock;
}
class Genode::Cancelable_lock
{
private:
class Applicant
{
private:
Thread *_thread_base;
Applicant *_to_wake_up;
public:
explicit Applicant(Thread *thread_base)
: _thread_base(thread_base), _to_wake_up(0) { }
void applicant_to_wake_up(Applicant *to_wake_up) {
_to_wake_up = to_wake_up; }
Applicant *applicant_to_wake_up() { return _to_wake_up; }
Thread *thread_base() { return _thread_base; }
/**
* Called from previous lock owner
*/
void wake_up();
bool operator == (Applicant &a) { return _thread_base == a.thread_base(); }
bool operator != (Applicant &a) { return _thread_base != a.thread_base(); }
};
/*
* Note that modifications of the applicants queue must be performed
* atomically. Hence, we use the additional spinlock here.
*/
volatile int _spinlock_state;
volatile int _state;
Applicant* volatile _last_applicant;
Applicant _owner;
public:
enum State { LOCKED, UNLOCKED };
/**
* Constructor
*/
explicit Cancelable_lock(State initial = UNLOCKED);
/**
* Try to aquire the lock and block while the lock is not free
*
* \throw Genode::Blocking_canceled
*/
void lock();
/**
* Release lock
*/
void unlock();
/**
* Lock guard
*/
typedef Genode::Lock_guard<Cancelable_lock> Guard;
};
#endif /* _INCLUDE__BASE__CANCELABLE_LOCK_H_ */