Ticket #643: Thread.RegisterExternal.d

/**
 * The thread module provides support for thread creation and management.
 *
 * Copyright: Copyright (C) 2005-2006 Sean Kelly.  All rights reserved.
 * License:   BSD style: $(LICENSE)
 * Authors:   Sean Kelly
 */
module tango.core.Thread;


// this should be true for most architectures
version = StackGrowsDown;


public
{
    import tango.core.Type : Interval;
}
private
{
    import tango.core.Exception;


    //
    // exposed by compiler runtime
    //
    extern (C) void* rt_stackBottom();
    extern (C) void* rt_stackTop();


    void* getStackBottom()
    {
        return rt_stackBottom();
    }


    void* getStackTop()
    {
        version( D_InlineAsm_X86 )
        {
            asm
            {
                naked;
                mov EAX, ESP;
                ret;
            }
        }
        else
        {
            return rt_stackTop();
        }
    }
}


////////////////////////////////////////////////////////////////////////////////
// Thread Entry Point and Signal Handlers
////////////////////////////////////////////////////////////////////////////////


version( Win32 )
{
    private
    {
        import tango.stdc.stdint : uintptr_t; // for _beginthreadex decl below
        import tango.sys.win32.UserGdi;

        const DWORD TLS_OUT_OF_INDEXES  = 0xFFFFFFFF;

        //
        // avoid multiple imports via tango.sys.windows.process
        //
        extern (Windows) alias uint function(void*) btex_fptr;
        extern (C) uintptr_t _beginthreadex(void*, uint, btex_fptr, void*, uint, uint*);


        //
        // entry point for Windows threads
        //
        extern (Windows) uint thread_entryPoint( void* arg )
        {
            Thread  obj = cast(Thread) arg;
            assert( obj );
            scope( exit ) Thread.remove( obj );

            assert( obj.m_curr is &obj.m_main );
            obj.m_main.bstack = getStackBottom();
            obj.m_main.tstack = obj.m_main.bstack;
            Thread.add( &obj.m_main );
            Thread.setThis( obj );

            // NOTE: No GC allocations may occur until the stack pointers have
            //       been set and Thread.getThis returns a valid reference to
            //       this thread object (this latter condition is not strictly
            //       necessary on Win32 but it should be followed for the sake
            //       of consistency).

            // TODO: Consider putting an auto exception object here (using
            //       alloca) forOutOfMemoryError plus something to track
            //       whether an exception is in-flight?

            try
            {
                obj.run();
            }
            catch( Object o )
            {
                obj.m_unhandled = o;
            }
            return 0;
        }


        //
        // copy of the same-named function in phobos.std.thread--it uses the
        // Windows naming convention to be consistent with GetCurrentThreadId
        //
        HANDLE GetCurrentThreadHandle()
        {
            const uint DUPLICATE_SAME_ACCESS = 0x00000002;

            HANDLE curr = GetCurrentThread(),
                   proc = GetCurrentProcess(),
                   hndl;

            DuplicateHandle( proc, curr, proc, &hndl, 0, TRUE, DUPLICATE_SAME_ACCESS );
            return hndl;
        }
    }
}
else version( Posix )
{
    private
    {
        import tango.stdc.posix.semaphore;
        import tango.stdc.posix.pthread;
        import tango.stdc.posix.signal;
        import tango.stdc.posix.time;
        import tango.stdc.errno;

        extern (C) int getErrno();

        version( GNU )
        {
            import gcc.builtins;
        }


        //
        // entry point for POSIX threads
        //
        extern (C) void* thread_entryPoint( void* arg )
        {
            Thread  obj = cast(Thread) arg;
            assert( obj );
            scope( exit )
            {
                // NOTE: isRunning should be set to false after the thread is
                //       removed or a double-removal could occur between this
                //       function and thread_suspendAll.
                Thread.remove( obj );
                obj.m_isRunning = false;
            }

            static extern (C) void thread_cleanupHandler( void* arg )
            {
                Thread  obj = cast(Thread) arg;
                assert( obj );

                // NOTE: If the thread terminated abnormally, just set it as
                //       not running and let thread_suspendAll remove it from
                //       the thread list.  This is safer and is consistent
                //       with the Windows thread code.
                obj.m_isRunning = false;
            }

            // NOTE: Using void to skip the initialization here relies on
            //       knowledge of how pthread_cleanup is implemented.  It may
            //       not be appropriate for all platforms.  However, it does
            //       avoid the need to link the pthread module.  If any
            //       implementation actually requires default initialization
            //       then pthread_cleanup should be restructured to maintain
            //       the current lack of a link dependency.
            pthread_cleanup cleanup = void;
            cleanup.push( &thread_cleanupHandler, cast(void*) obj );

            // NOTE: For some reason this does not always work for threads.
            //obj.m_main.bstack = getStackBottom();
            version( D_InlineAsm_X86 )
            {
                static void* getBasePtr()
                {
                    asm
                    {
                        naked;
                        mov EAX, EBP;
                        ret;
                    }
                }

                obj.m_main.bstack = getBasePtr();
            }
            else version( StackGrowsDown )
                obj.m_main.bstack = &obj + 1;
            else
                obj.m_main.bstack = &obj;
            obj.m_main.tstack = obj.m_main.bstack;
            assert( obj.m_curr == &obj.m_main );
            Thread.add( &obj.m_main );
            Thread.setThis( obj );

            // NOTE: No GC allocations may occur until the stack pointers have
            //       been set and Thread.getThis returns a valid reference to
            //       this thread object (this latter condition is not strictly
            //       necessary on Win32 but it should be followed for the sake
            //       of consistency).

            // TODO: Consider putting an auto exception object here (using
            //       alloca) forOutOfMemoryError plus something to track
            //       whether an exception is in-flight?

            try
            {
                obj.run();
            }
            catch( Object o )
            {
                obj.m_unhandled = o;
            }
            return null;
        }


        //
        // used to track the number of suspended threads
        //
        sem_t   suspendCount;


        extern (C) void thread_suspendHandler( int sig )
        in
        {
            assert( sig == SIGUSR1 );
        }
        body
        {
            version( D_InlineAsm_X86 )
            {
                asm
                {
                    pushad;
                }
            }
            else version( GNU )
            {
                __builtin_unwind_init();
            }
            else
            {
                static assert( false, "Architecture not supported." );
            }

            // NOTE: Since registers are being pushed and popped from the stack,
            //       any other stack data used by this function should be gone
            //       before the stack cleanup code is called below.
            {
                Thread  obj = Thread.getThis();

                // NOTE: The thread reference returned by getThis is set within
                //       the thread startup code, so it is possible that this
                //       handler may be called before the reference is set.  In
                //       this case it is safe to simply suspend and not worry
                //       about the stack pointers as the thread will not have
                //       any references to GC-managed data.
                if( obj && !obj.m_lock )
                {
                    obj.m_curr.tstack = getStackTop();
                }

                sigset_t    sigres = void;
                int         status;

                status = sigfillset( &sigres );
                assert( status == 0 );

                status = sigdelset( &sigres, SIGUSR2 );
                assert( status == 0 );

                status = sem_post( &suspendCount );
                assert( status == 0 );

                sigsuspend( &sigres );

                if( obj && !obj.m_lock )
                {
                    obj.m_curr.tstack = obj.m_curr.bstack;
                }
            }

            version( D_InlineAsm_X86 )
            {
                asm
                {
                    popad;
                }
            }
            else version( GNU )
            {
                // registers will be popped automatically
            }
            else
            {
                static assert( false, "Architecture not supported." );
            }
        }


        extern (C) void thread_resumeHandler( int sig )
        in
        {
            assert( sig == SIGUSR2 );
        }
        body
        {

        }
    }
}
else
{
    // NOTE: This is the only place threading versions are checked.  If a new
    //       version is added, the module code will need to be searched for
    //       places where version-specific code may be required.  This can be
    //       easily accomlished by searching for 'Windows' or 'Posix'.
    static assert( false, "Unknown threading implementation." );
}


////////////////////////////////////////////////////////////////////////////////
// Thread
////////////////////////////////////////////////////////////////////////////////


/**
 * This class encapsulates all threading functionality for the D
 * programming language.  As thread manipulation is a required facility
 * for garbage collection, all user threads should derive from this
 * class, and instances of this class should never be explicitly deleted.
 * A new thread may be created using either derivation or composition, as
 * in the following example.
 *
 * Example:
 * -----------------------------------------------------------------------------
 *
 * class DerivedThread : Thread
 * {
 *     this()
 *     {
 *         super( &run );
 *     }
 *
 * private :
 *     void run()
 *     {
 *         printf( "Derived thread running.\n" );
 *     }
 * }
 *
 * void threadFunc()
 * {
 *     printf( "Composed thread running.\n" );
 * }
 *
 * // create instances of each type
 * Thread derived = new DerivedThread();
 * Thread composed = new Thread( &threadFunc );
 *
 * // start both threads
 * derived.start();
 * composed.start();
 *
 * -----------------------------------------------------------------------------
 */
class Thread
{
    ////////////////////////////////////////////////////////////////////////////
    // Initialization
    ////////////////////////////////////////////////////////////////////////////


    /**
     * Initializes a thread object which is associated with a static
     * D function.
     *
     * Params:
     *  fn = The thread function.
     *  sz = The stack size for this thread.
     *
     * In:
     *  fn must not be null.
     */
    this( void function() fn, size_t sz = 0 )
    in
    {
        assert( fn );
    }
    body
    {
        m_fn   = fn;
        m_sz   = sz;
        m_call = Call.FN;
        m_curr = &m_main;
    }


    /**
     * Initializes a thread object which is associated with a dynamic
     * D function.
     *
     * Params:
     *  dg = The thread function.
     *  sz = The stack size for this thread.
     *
     * In:
     *  dg must not be null.
     */
    this( void delegate() dg, size_t sz = 0 )
    in
    {
        assert( dg );
    }
    body
    {
        m_dg   = dg;
        m_sz   = sz;
        m_call = Call.DG;
        m_curr = &m_main;
    }


    /**
     * Cleans up any remaining resources used by this object.
     */
    ~this()
    {
        if( m_addr == m_addr.init )
        {
            return;
        }

        version( Win32 )
        {
            m_addr = m_addr.init;
            CloseHandle( m_hndl );
            m_hndl = m_hndl.init;
        }
        else version( Posix )
        {
            pthread_detach( m_addr );
            m_addr = m_addr.init;
        }
    }


    ////////////////////////////////////////////////////////////////////////////
    // General Actions
    ////////////////////////////////////////////////////////////////////////////


    /**
     * Registers an "external" thread (a thread not created using Tango's API).
     */
    static void registerExternalThread()
    {
        Thread t = new Thread();

        version(Win32)
        {
            t.m_addr  = GetCurrentThreadId();
            t.m_hndl  = GetCurrentThreadHandle();
        }
        else
        {
            unimplemented();
        }

        t.m_isDaemon = true;

        t.m_main.bstack = getStackBottom();
        t.m_main.tstack = t.m_main.bstack;
        Thread.add( &t.m_main );
        Thread.setThis( t );
        Thread.add(t);
    }

    /**
     * Starts the thread and invokes the function or delegate passed upon
     * construction.
     *
     * In:
     *  This routine may only be called once per thread instance.
     *
     * Throws:
     *  ThreadException if the thread fails to start.
     */
    final void start()
    in
    {
        assert( !next && !prev );
    }
    body
    {
        version( Win32 ) {} else
        version( Posix )
        {
            pthread_attr_t  attr;

            if( pthread_attr_init( &attr ) )
                throw new ThreadException( "Error initializing thread attributes" );
            if( m_sz && pthread_attr_setstacksize( &attr, m_sz ) )
                throw new ThreadException( "Error initializing thread stack size" );
        }

        // NOTE: This operation needs to be synchronized to avoid a race
        //       condition with the GC.  Without this lock, the thread
        //       could start and allocate memory before being added to
        //       the global thread list, preventing it from being scanned
        //       and causing memory to be collected that is still in use.
        synchronized( slock )
        {
            version( Win32 )
            {
                m_hndl = cast(HANDLE) _beginthreadex( null, m_sz, &thread_entryPoint, cast(void*) this, 0, &m_addr );
                if( cast(size_t) m_hndl == 0 )
                    throw new ThreadException( "Error creating thread" );
            }
            else version( Posix )
            {
                m_isRunning = true;
                scope( failure ) m_isRunning = false;

                if( pthread_create( &m_addr, &attr, &thread_entryPoint, cast(void*) this ) != 0 )
                    throw new ThreadException( "Error creating thread" );
            }
            multiThreadedFlag = true;
            add( this );
        }
    }


    /**
     * Waits for this thread to complete.  If the thread terminated as the
     * result of an unhandled exception, this exception will be rethrown.
     *
     * Params:
     *  rethrow = Rethrow any unhandled exception which may have caused this
     *            thread to terminate.
     *
     * Throws:
     *  ThreadException if the operation fails.
     *  Any exception not handled by the joined thread.
     */
    final void join( bool rethrow = true )
    {
        version( Win32 )
        {
            if( WaitForSingleObject( m_hndl, INFINITE ) != WAIT_OBJECT_0 )
                throw new ThreadException( "Unable to join thread" );
            // NOTE: m_addr must be cleared before m_hndl is closed to avoid
            //       a race condition with isRunning.  The operation is labeled
            //       volatile to prevent compiler reordering.
            volatile m_addr = m_addr.init;
            CloseHandle( m_hndl );
            m_hndl = m_hndl.init;
        }
        else version( Posix )
        {
            if( pthread_join( m_addr, null ) != 0 )
                throw new ThreadException( "Unable to join thread" );
            // NOTE: pthread_join acts as a substitute for pthread_detach,
            //       which is normally called by the dtor.  Setting m_addr
            //       to zero ensures that pthread_detach will not be called
            //       on object destruction.
            volatile m_addr = m_addr.init;
        }
        if( rethrow && m_unhandled )
        {
            throw m_unhandled;
        }
    }


    ////////////////////////////////////////////////////////////////////////////
    // General Properties
    ////////////////////////////////////////////////////////////////////////////


    /**
     * Gets the user-readable label for this thread.
     *
     * Returns:
     *  The name of this thread.
     */
    final char[] name()
    {
        synchronized( this )
        {
            return m_name;
        }
    }


    /**
     * Sets the user-readable label for this thread.
     *
     * Params:
     *  val = The new name of this thread.
     */
    final void name( char[] val )
    {
        synchronized( this )
        {
            m_name = val.dup;
        }
    }


    /**
     * Gets the daemon status for this thread.
     *
     * Returns:
     *  true if this is a daemon thread.
     */
    final bool isDaemon()
    {
        synchronized( this )
        {
            return m_isDaemon;
        }
    }


    /**
     * Sets the daemon status for this thread.
     *
     * Params:
     *  val = The new daemon status for this thread.
     */
    final void isDaemon( bool val )
    {
        synchronized( this )
        {
            m_isDaemon = val;
        }
    }


    /**
     * Tests whether this thread is running.
     *
     * Returns:
     *  true if the thread is running, false if not.
     */
    final bool isRunning()
    {
        if( m_addr == m_addr.init )
        {
            return false;
        }

        version( Win32 )
        {
            uint ecode = 0;
            GetExitCodeThread( m_hndl, &ecode );
            return ecode == STILL_ACTIVE;
        }
        else version( Posix )
        {
            // NOTE: It should be safe to access this value without
            //       memory barriers because word-tearing and such
            //       really isn't an issue for boolean values.
            return m_isRunning;
        }
    }


    ////////////////////////////////////////////////////////////////////////////
    // Thread Priority Actions
    ////////////////////////////////////////////////////////////////////////////


    /**
     * The minimum scheduling priority that may be set for a thread.  On
     * systems where multiple scheduling policies are defined, this value
     * represents the minimum valid priority for the scheduling policy of
     * the process.
     */
    static const int PRIORITY_MIN;


    /**
     * The maximum scheduling priority that may be set for a thread.  On
     * systems where multiple scheduling policies are defined, this value
     * represents the minimum valid priority for the scheduling policy of
     * the process.
     */
    static const int PRIORITY_MAX;


    /**
     * Gets the scheduling priority for the associated thread.
     *
     * Returns:
     *  The scheduling priority of this thread.
     */
    final int priority()
    {
        version( Win32 )
        {
            return GetThreadPriority( m_hndl );
        }
        else version( Posix )
        {
            int         policy;
            sched_param param;

            if( pthread_getschedparam( m_addr, &policy, &param ) )
                throw new ThreadException( "Unable to get thread priority" );
            return param.sched_priority;
        }
    }


    /**
     * Sets the scheduling priority for the associated thread.
     *
     * Params:
     *  val = The new scheduling priority of this thread.
     */
    final void priority( int val )
    {
        version( Win32 )
        {
            if( !SetThreadPriority( m_hndl, val ) )
                throw new ThreadException( "Unable to set thread priority" );
        }
        else version( Posix )
        {
            // NOTE: pthread_setschedprio is not implemented on linux, so use
            //       the more complicated get/set sequence below.
            //if( pthread_setschedprio( m_addr, val ) )
            //    throw new ThreadException( "Unable to set thread priority" );

            int         policy;
            sched_param param;

            if( pthread_getschedparam( m_addr, &policy, &param ) )
                throw new ThreadException( "Unable to set thread priority" );
            param.sched_priority = val;
            if( pthread_setschedparam( m_addr, policy, &param ) )
                throw new Thr