Thread.h

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//
// Thread.h
//
// Library: Foundation
// Package: Threading
// Module:  Thread
//
// Definition of the Thread class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
 
 
#ifndef Foundation_Thread_INCLUDED
#define Foundation_Thread_INCLUDED
 
 
#include "Poco/Foundation.h"
#include "Poco/Event.h"
#include "Poco/Mutex.h"
 
 
#if defined(POCO_OS_FAMILY_WINDOWS)
#if defined(_WIN32_WCE)
#include "Poco/Thread_WINCE.h"
#else
#include "Poco/Thread_WIN32.h"
#endif
#elif defined(POCO_VXWORKS)
#include "Poco/Thread_VX.h"
#else
#include "Poco/Thread_POSIX.h"
#endif
 
 
namespace Poco {
 
 
class Runnable;
class ThreadLocalStorage;
 
 
class Foundation_API Thread: private ThreadImpl
    /// This class implements a platform-independent
    /// wrapper to an operating system thread.
    ///
    /// Every Thread object gets a unique (within
    /// its process) numeric thread ID.
    /// Furthermore, a thread can be assigned a name.
    /// The name of a thread can be changed at any time.
{
public:
    typedef ThreadImpl::TIDImpl TID;
 
    using ThreadImpl::Callable;
 
    enum Priority
        /// Thread priorities.
    {
        PRIO_LOWEST  = PRIO_LOWEST_IMPL, /// The lowest thread priority.
        PRIO_LOW     = PRIO_LOW_IMPL,    /// A lower than normal thread priority.
        PRIO_NORMAL  = PRIO_NORMAL_IMPL, /// The normal thread priority.
        PRIO_HIGH    = PRIO_HIGH_IMPL,   /// A higher than normal thread priority.
        PRIO_HIGHEST = PRIO_HIGHEST_IMPL /// The highest thread priority.
    };
 
    enum Policy
    {
        POLICY_DEFAULT = POLICY_DEFAULT_IMPL
    };
 
    Thread();
        /// Creates a thread. Call start() to start it.
 
    Thread(const std::string& name);
        /// Creates a named thread. Call start() to start it.
 
    ~Thread();
        /// Destroys the thread.
 
    int id() const;
        /// Returns the unique thread ID of the thread.
 
    TID tid() const;
        /// Returns the native thread ID of the thread.
 
    std::string name() const;
        /// Returns the name of the thread.
 
    std::string getName() const;
        /// Returns the name of the thread.
 
    void setName(const std::string& name);
        /// Sets the name of the thread.
 
    void setPriority(Priority prio);
        /// Sets the thread's priority.
        ///
        /// Some platform only allow changing a thread's priority
        /// if the process has certain privileges.
 
    Priority getPriority() const;
        /// Returns the thread's priority.
 
    void setOSPriority(int prio, int policy = POLICY_DEFAULT);
        /// Sets the thread's priority, using an operating system specific
        /// priority value. Use getMinOSPriority() and getMaxOSPriority() to
        /// obtain mininum and maximum priority values. Additionally,
        /// a scheduling policy can be specified. The policy is currently
        /// only used on POSIX platforms where the values SCHED_OTHER (default),
        /// SCHED_FIFO and SCHED_RR are supported.
 
    int getOSPriority() const;
        /// Returns the thread's priority, expressed as an operating system
        /// specific priority value.
        ///
        /// May return 0 if the priority has not been explicitly set.
 
    static int getMinOSPriority(int policy = POLICY_DEFAULT);
        /// Returns the minimum operating system-specific priority value,
        /// which can be passed to setOSPriority() for the given policy.
 
    static int getMaxOSPriority(int policy = POLICY_DEFAULT);
        /// Returns the maximum operating system-specific priority value,
        /// which can be passed to setOSPriority() for the given policy.
 
    void setStackSize(int size);
        /// Sets the thread's stack size in bytes.
        /// Setting the stack size to 0 will use the default stack size.
        /// Typically, the real stack size is rounded up to the nearest
        /// page size multiple.
 
    int getStackSize() const;
        /// Returns the thread's stack size in bytes.
        /// If the default stack size is used, 0 is returned.
 
    void start(Runnable& target);
        /// Starts the thread with the given target.
        ///
        /// Note that the given Runnable object must remain
        /// valid during the entire lifetime of the thread, as
        /// only a reference to it is stored internally.
 
    void start(Poco::SharedPtr<Runnable> pTarget);
        /// Starts the thread with the given target.
        ///
        /// The Thread ensures that the given target stays
        /// alive while the thread is running.
 
    void start(Callable target, void* pData = 0);
        /// Starts the thread with the given target and parameter.
 
    template <class Functor>
    void startFunc(const Functor& fn)
        /// Starts the thread with the given functor object or lambda.
    {
        startImpl(new FunctorRunnable<Functor>(fn));
    }
 
    template <class Functor>
    void startFunc(Functor&& fn)
        /// Starts the thread with the given functor object or lambda.
    {
        startImpl(new FunctorRunnable<Functor>(std::move(fn)));
    }
 
    void join();
        /// Waits until the thread completes execution.
        /// If multiple threads try to join the same
        /// thread, the result is undefined.
 
    void join(long milliseconds);
        /// Waits for at most the given interval for the thread
        /// to complete. Throws a TimeoutException if the thread
        /// does not complete within the specified time interval.
 
    bool tryJoin(long milliseconds);
        /// Waits for at most the given interval for the thread
        /// to complete. Returns true if the thread has finished,
        /// false otherwise.
 
    bool isRunning() const;
        /// Returns true if the thread is running.
 
    static bool trySleep(long milliseconds);
        /// Starts an interruptible sleep. When trySleep() is called,
        /// the thread will remain suspended until:
        ///   - the timeout expires or
        ///   - wakeUp() is called
        ///
        /// Function returns true if sleep attempt was completed, false
        /// if sleep was interrupted by a wakeUp() call.
        /// A frequent scenario where trySleep()/wakeUp() pair of functions
        /// is useful is with threads spending most of the time idle,
        /// with periodic activity between the idle times; trying to sleep
        /// (as opposed to sleeping) allows immediate ending of idle thread
        /// from the outside.
        ///
        /// The trySleep() and wakeUp() calls should be used with
        /// understanding that the suspended state is not a true sleep,
        /// but rather a state of waiting for an event, with timeout
        /// expiration. This makes order of calls significant; calling
        /// wakeUp() before calling trySleep() will prevent the next
        /// trySleep() call to actually suspend the thread (which, in
        /// some scenarios, may be desirable behavior).
 
    void wakeUp();
        /// Wakes up the thread which is in the state of interruptible
        /// sleep. For threads that are not suspended, calling this
        /// function has the effect of preventing the subsequent
        /// trySleep() call to put thread in a suspended state.
 
    static void sleep(long milliseconds);
        /// Suspends the current thread for the specified
        /// amount of time.
 
    static void yield();
        /// Yields cpu to other threads.
 
    static Thread* current();
        /// Returns the Thread object for the currently active thread.
        /// If the current thread is the main thread, 0 is returned.
 
    static TID currentTid();
        /// Returns the native thread ID for the current thread.
 
protected:
    ThreadLocalStorage& tls();
        /// Returns a reference to the thread's local storage.
 
    void clearTLS();
        /// Clears the thread's local storage.
 
    std::string makeName();
        /// Creates a unique name for a thread.
 
    static int uniqueId();
        /// Creates and returns a unique id for a thread.
 
    template <class Functor>
    class FunctorRunnable: public Runnable
    {
    public:
        FunctorRunnable(const Functor& functor):
            _functor(functor)
        {
        }
 
        FunctorRunnable(Functor&& functor):
            _functor(std::move(functor))
        {
        }
 
        ~FunctorRunnable()
        {
        }
 
        void run()
        {
            _functor();
        }
 
    private:
        Functor _functor;
    };
 
private:
    Thread(const Thread&);
    Thread& operator = (const Thread&);
 
    int                 _id;
    std::string         _name;
    ThreadLocalStorage* _pTLS;
    Event               _event;
    mutable FastMutex   _mutex;
 
    friend class ThreadLocalStorage;
    friend class PooledThread;
};
 
 
//
// inlines
//
inline Thread::TID Thread::tid() const
{
    return tidImpl();
}
 
 
inline int Thread::id() const
{
    return _id;
}
 
 
inline std::string Thread::name() const
{
    FastMutex::ScopedLock lock(_mutex);
 
    return _name;
}
 
 
inline std::string Thread::getName() const
{
    FastMutex::ScopedLock lock(_mutex);
 
    return _name;
}
 
 
inline bool Thread::isRunning() const
{
    return isRunningImpl();
}
 
 
inline void Thread::sleep(long milliseconds)
{
    sleepImpl(milliseconds);
}
 
 
inline void Thread::yield()
{
    yieldImpl();
}
 
 
inline Thread* Thread::current()
{
    return static_cast<Thread*>(currentImpl());
}
 
 
inline void Thread::setOSPriority(int prio, int policy)
{
    setOSPriorityImpl(prio, policy);
}
 
 
inline int Thread::getOSPriority() const
{
    return getOSPriorityImpl();
}
 
 
inline int Thread::getMinOSPriority(int policy)
{
    return ThreadImpl::getMinOSPriorityImpl(policy);
}
 
 
inline int Thread::getMaxOSPriority(int policy)
{
    return ThreadImpl::getMaxOSPriorityImpl(policy);
}
 
 
inline void Thread::setStackSize(int size)
{
    setStackSizeImpl(size);
}
 
 
inline int Thread::getStackSize() const
{
    return getStackSizeImpl();
}
 
 
inline Thread::TID Thread::currentTid()
{
    return currentTidImpl();
}
 
 
} // namespace Poco
 
 
#endif // Foundation_Thread_INCLUDED