Semaphore.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#ifndef SEMAPHORE_H
#define SEMAPHORE_H
#include "pedigree/kernel/Atomic.h"
#include "pedigree/kernel/Spinlock.h"
#include "pedigree/kernel/compiler.h"
#include "pedigree/kernel/process/Event.h"
#include "pedigree/kernel/process/WaitQueue.h"
#include "pedigree/kernel/processor/types.h"
#include "pedigree/kernel/utilities/Result.h"
#include "pedigree/kernel/utilities/new"
 
#include <config.h>
 
class EXPORTED_PUBLIC Semaphore {
 public:
  enum SemaphoreError {
    TimedOut,
    Interrupted,
    NoError,
  };
 
#if HOSTED && PEDIGREE_HOSTED_SMOKE_TESTS
  using BeforeWaitHook = void (*)(Semaphore*);
  static void setBeforeWaitHook(BeforeWaitHook hook);
 
  enum MutexTransitionWindow {
    MutexCounterAcquired,
    MutexOwnerReleased,
  };
  using MutexTransitionHook = void (*)(MutexTransitionWindow window);
 
  static void setMutexTransitionHook(MutexTransitionHook hook);
 
  static size_t getHostedTimeoutCreateCount();
  static size_t getHostedTimeoutDestroyCount();
#endif
 
  Semaphore(size_t nInitialValue, bool canInterrupt = true);
  virtual ~Semaphore();
 
  MUST_USE_RESULT bool acquireWithError(size_t n, size_t timeoutSecs, size_t timeoutUsecs,
                                        SemaphoreError& error);
 
  MUST_USE_RESULT bool acquireForCompletion(size_t n = 1, size_t timeoutSecs = 0,
                                            size_t timeoutUsecs = 0);
 
  bool acquire(size_t n = 1, size_t timeoutSecs = 0, size_t timeoutUsecs = 0);
 
  bool tryAcquire(size_t n = 1);
 
  MUST_USE_RESULT size_t drainAvailable();
 
  void release(size_t n = 1);
 
  ssize_t getValue();
 
  const void* getDebugMutexOwner() const;
 
 protected:
  void initialiseMutex(bool locked);
  void destroyMutex();
  bool mutexOwnedByCurrentThread() const;
 
 private:
  typedef Result<bool, SemaphoreError> SemaphoreResult;
 
  MUST_USE_RESULT SemaphoreResult acquireWithResult(size_t n = 1, size_t timeoutSecs = 0,
                                                    size_t timeoutUsecs = 0,
                                                    bool deferTerminal = false);
 
  Semaphore(const Semaphore&);
  void operator=(const Semaphore&);
 
  class SemaphoreEvent : public Event {
   public:
    explicit SemaphoreEvent(size_t nestingLevel);
    virtual ~SemaphoreEvent();
    virtual size_t serialize(uint8_t* pBuffer);
    static bool unserialize(uint8_t* pBuffer, SemaphoreEvent& event);
    virtual size_t getNumber();
  };
 
  size_t magic;
 
  Atomic<ssize_t> m_Counter;
  WaitQueue m_Waiters;
  bool m_bCanInterrupt;
};
 
#endif