/*  PCSX2 - PS2 Emulator for PCs
 *  Copyright (C) 2002-2009  PCSX2 Dev Team
 *
 *  PCSX2 is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU Lesser General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  PCSX2 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *  PURPOSE.  See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with PCSX2.
 *  If not, see <http://www.gnu.org/licenses/>.
 */


#include "PrecompiledHeader.h"

#ifdef _WIN32
#	include <wx/msw/wrapwin.h>	// for thread renaming features
#endif
#include <wx/app.h>

#ifdef __LINUX__
#	include <signal.h>		// for pthread_kill, which is in pthread.h on w32-pthreads
#endif

#include "Threading.h"
#include "wxBaseTools.h"

#include <wx/datetime.h>
#include <wx/thread.h>


using namespace Threading;

namespace Threading
{
	static const wxTimeSpan ts_msec_250( 0, 0, 0, 250 );

	void PersistentThread::_pt_callback_cleanup( void* handle )
	{
		((PersistentThread*)handle)->_ThreadCleanup();
	}

	PersistentThread::PersistentThread() :
		m_name( L"PersistentThread" )
	,	m_thread()
	,	m_sem_event()
	,	m_sem_finished()
	,	m_lock_start()
	,	m_detached( true )		// start out with m_thread in detached/invalid state
	,	m_running( false )
	{
	}

	// This destructor performs basic "last chance" cleanup, which is a blocking join
	// against the thread. Extending classes should almost always implement their own
	// thread closure process, since any PersistentThread will, by design, not terminate
	// unless it has been properly canceled.
	//
	// Thread safetly: This class must not be deleted from its own thread.  That would be
	// like marrying your sister, and then cheating on her with your daughter.
	PersistentThread::~PersistentThread() throw()
	{
		try
		{
			Console.WriteLn( L"Thread Log: Executing destructor for " + m_name );

			if( m_running )
			{
				Console.WriteLn( L"\tWaiting for running thread to end...");
	#if wxUSE_GUI
				m_sem_finished.WaitGui();
	#else
				m_sem_finished.Wait();
	#endif
				// Need to lock here so that the thread can finish shutting down before
				// it gets destroyed, otherwise th mutex handle would become invalid.
				ScopedLock locker( m_lock_start );
			}
			Threading::Sleep( 1 );
			Detach();
		}
		DESTRUCTOR_CATCHALL
	}

	// Main entry point for starting or e-starting a persistent thread.  This function performs necessary
	// locks and checks for avoiding race conditions, and then calls OnStart() immeediately before
	// the actual thread creation.  Extending classes should generally not override Start(), and should
	// instead override DoPrepStart instead.
	//
	// This function should not be called from the owner thread.
	void PersistentThread::Start()
	{
		ScopedLock startlock( m_lock_start );		// Prevents sudden parallel startup
		if( m_running ) return;

		Detach();		// clean up previous thread handle, if one exists.
		m_sem_finished.Reset();

		OnStart();

		if( pthread_create( &m_thread, NULL, _internal_callback, this ) != 0 )
			throw Exception::ThreadCreationError();

		m_detached = false;
	}

	// Returns: TRUE if the detachment was performed, or FALSE if the thread was
	// already detached or isn't running at all.
	// This function should not be called from the owner thread.
	bool PersistentThread::Detach()
	{
		pxAssertMsg( !IsSelf(), "Thread affinity error." );		// not allowed from our own thread.

		if( _InterlockedExchange( &m_detached, true ) ) return false;
		pthread_detach( m_thread );
		return true;
	}

	// Remarks:
	//   Provision of non-blocking Cancel() is probably academic, since destroying a PersistentThread
	//   object performs a blocking Cancel regardless of if you explicitly do a non-blocking Cancel()
	//   prior, since the ExecuteTaskInThread() method requires a valid object state.  If you really need
	//   fire-and-forget behavior on threads, use pthreads directly for now.
	//
	// This function should not be called from the owner thread.
	//
	// Parameters:
	//   isBlocking - indicates if the Cancel action should block for thread completion or not.
	//
	void PersistentThread::Cancel( bool isBlocking )
	{
		pxAssertMsg( !IsSelf(), "Thread affinity error." );

		if( !m_running ) return;

		if( m_detached )
		{
			Console.Notice( "Threading Warning: Attempted to cancel detached thread; Ignoring..." );
			return;
		}

		pthread_cancel( m_thread );

		if( isBlocking )
		{
#if wxUSE_GUI
			m_sem_finished.WaitGui();
#else
			m_sem_finished.Wait();
#endif
		}
	}

	// Blocks execution of the calling thread until this thread completes its task.  The
	// caller should make sure to signal the thread to exit, or else blocking may deadlock the
	// calling thread.  Classes which extend PersistentThread should override this method
	// and signal any necessary thread exit variables prior to blocking.
	//
	// Returns the return code of the thread.
	// This method is roughly the equivalent of pthread_join().
	//
	void PersistentThread::Block()
	{
		pxAssertDev( !IsSelf(), "Thread deadlock detected; Block() should never be called by the owner thread." );

		if( m_running )
#if wxUSE_GUI
			m_sem_finished.WaitGui();
#else
			m_sem_finished.Wait();
#endif
	}

	bool PersistentThread::IsSelf() const
	{
		return pthread_self() == m_thread;
	}

	bool PersistentThread::IsRunning() const
	{
	    return !!m_running;
	}

	// Throws an exception if the thread encountered one.  Uses the BaseException's Rethrow() method,
	// which ensures the exception type remains consistent.  Debuggable stacktraces will be lost, since
	// the thread will have allowed itself to terminate properly.
	void PersistentThread::RethrowException() const
	{
		if( !m_except ) return;
		m_except->Rethrow();
	}

	void PersistentThread::TestCancel()
	{
		pxAssert( IsSelf() );
		pthread_testcancel();
	}

	// Executes the virtual member method
	void PersistentThread::_try_virtual_invoke( void (PersistentThread::*method)() )
	{
		try {
			(this->*method)();
		}

		// ----------------------------------------------------------------------------
		// Neat repackaging for STL Runtime errors...
		//
		catch( std::runtime_error& ex )
		{
			m_except = new Exception::RuntimeError(
				// Diagnostic message:
				wxsFormat( L"(thread: %s) STL Runtime Error: %s\n\t%s",
					GetName().c_str(), fromUTF8( ex.what() ).c_str()
				),

				// User Message (not translated, std::exception doesn't have that kind of fancy!
				wxsFormat( L"A runtime error occurred in %s:\n\n%s (STL)",
					GetName().c_str(), fromUTF8( ex.what() ).c_str()
				)
			);
		}

		// ----------------------------------------------------------------------------
		catch( Exception::RuntimeError& ex )
		{
			m_except = ex.Clone();
			m_except->DiagMsg() = wxsFormat( L"(thread:%s) ", GetName().c_str() ) + m_except->DiagMsg();
		}

		// ----------------------------------------------------------------------------
		// Should we let logic errors propagate, or swallow them and let the thread manager
		// handle them?  Hmm..
		/*catch( std::logic_error& ex )
		{
			throw Exception::LogicError( wxsFormat( L"(thread: %s) STL Logic Error: %s\n\t%s",
				GetName().c_str(), fromUTF8( ex.what() ).c_str() )
			);
		}
		catch( Exception::LogicError& ex )
		{
			m_except = ex.Clone();
			m_except->DiagMsg() = wxsFormat( L"(thread:%s) ", GetName().c_str() ) + m_except->DiagMsg();
		}*/

		// ----------------------------------------------------------------------------
		// BaseException / std::exception  --  same deal.  Allow propagation or no?
		//
		/*catch( std::exception& ex )
		{
			throw Exception::BaseException( wxsFormat( L"(thread: %s) STL exception: %s\n\t%s",
				GetName().c_str(), fromUTF8( ex.what() ).c_str() )
			);
		}
		catch( Exception::BaseException& ex )
		{
			m_except = ex.Clone();
			m_except->DiagMsg() = wxsFormat( L"(thread:%s) ", GetName().c_str() ) + m_except->DiagMsg();
		}*/
	}

	// invoked internally when canceling or exiting the thread.  Extending classes should implement
	// OnCleanupInThread() to extend cleanup functionality.
	void PersistentThread::_ThreadCleanup()
	{
		pxAssertMsg( IsSelf(), "Thread affinity error." );	// only allowed from our own thread, thanks.

		// Typically thread cleanup needs to lock against thread startup, since both
		// will perform some measure of variable inits or resets, depending on how the
		// derived class is implemented.
		ScopedLock startlock( m_lock_start );

		_try_virtual_invoke( &PersistentThread::OnCleanupInThread );

		m_running = false;
		m_sem_finished.Post();
	}

	wxString PersistentThread::GetName() const
	{
		return m_name;
	}

	void PersistentThread::_internal_execute()
	{
		m_running = true;
		_DoSetThreadName( m_name );
		_try_virtual_invoke( &PersistentThread::ExecuteTaskInThread );
	}

	void PersistentThread::OnStart() {}
	void PersistentThread::OnCleanupInThread() {}

	// passed into pthread_create, and is used to dispatch the thread's object oriented
	// callback function
	void* PersistentThread::_internal_callback( void* itsme )
	{
		jASSUME( itsme != NULL );
		PersistentThread& owner = *((PersistentThread*)itsme);

		pthread_cleanup_push( _pt_callback_cleanup, itsme );
		owner._internal_execute();
		pthread_cleanup_pop( true );
		return NULL;
	}

	void PersistentThread::_DoSetThreadName( const wxString& name )
	{
		_DoSetThreadName( toUTF8(name) );
	}

	void PersistentThread::_DoSetThreadName( __unused const char* name )
	{
		pxAssertMsg( IsSelf(), "Thread affinity error." );	// only allowed from our own thread, thanks.

		// This feature needs Windows headers and MSVC's SEH support:

	#if defined(_WINDOWS_) && defined (_MSC_VER)

		// This code sample was borrowed form some obscure MSDN article.
		// In a rare bout of sanity, it's an actual Micrsoft-published hack
		// that actually works!

		static const int MS_VC_EXCEPTION = 0x406D1388;

		#pragma pack(push,8)
		struct THREADNAME_INFO
		{
			DWORD dwType; // Must be 0x1000.
			LPCSTR szName; // Pointer to name (in user addr space).
			DWORD dwThreadID; // Thread ID (-1=caller thread).
			DWORD dwFlags; // Reserved for future use, must be zero.
		};
		#pragma pack(pop)

		THREADNAME_INFO info;
		info.dwType		= 0x1000;
		info.szName		= name;
		info.dwThreadID	= GetCurrentThreadId();
		info.dwFlags	= 0;

		__try
		{
			RaiseException( MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), (ULONG_PTR*)&info );
		}
		__except(EXCEPTION_EXECUTE_HANDLER)
		{
		}
	#endif
	}

// --------------------------------------------------------------------------------------
//  BaseTaskThread Implementations
// --------------------------------------------------------------------------------------

	// Tells the thread to exit and then waits for thread termination.
	void BaseTaskThread::Block()
	{
		if( !IsRunning() ) return;
		m_Done = true;
		m_sem_event.Post();
		PersistentThread::Block();
	}

	// Initiates the new task.  This should be called after your own StartTask has
	// initialized internal variables / preparations for task execution.
	void BaseTaskThread::PostTask()
	{
		pxAssert( !m_detached );

		ScopedLock locker( m_lock_TaskComplete );
		m_TaskPending = true;
		m_post_TaskComplete.Reset();
		m_sem_event.Post();
	}

	// Blocks current thread execution pending the completion of the parallel task.
	void BaseTaskThread::WaitForResult()
	{
		if( m_detached || !m_running ) return;
		if( m_TaskPending )
		#ifdef wxUSE_GUI
			m_post_TaskComplete.WaitGui();
		#else
			m_post_TaskComplete.Wait();
		#endif

		m_post_TaskComplete.Reset();
	}

	void BaseTaskThread::ExecuteTaskInThread()
	{
		while( !m_Done )
		{
			// Wait for a job -- or get a pthread_cancel.  I'm easy.
			m_sem_event.Wait();

			Task();
			m_lock_TaskComplete.Lock();
			m_TaskPending = false;
			m_post_TaskComplete.Post();
			m_lock_TaskComplete.Unlock();
		};

		return;
	}

// --------------------------------------------------------------------------------------
//  pthread Cond is an evil api that is not suited for Pcsx2 needs.
//  Let's not use it. (Air)
// --------------------------------------------------------------------------------------

#if 0
	WaitEvent::WaitEvent()
	{
		int err = 0;

		err = pthread_cond_init(&cond, NULL);
		err = pthread_mutex_init(&mutex, NULL);
	}

	WaitEvent::~WaitEvent()
	{
		pthread_cond_destroy( &cond );
		pthread_mutex_destroy( &mutex );
	}

	void WaitEvent::Set()
	{
		pthread_mutex_lock( &mutex );
		pthread_cond_signal( &cond );
		pthread_mutex_unlock( &mutex );
	}

	void WaitEvent::Wait()
	{
		pthread_mutex_lock( &mutex );
		pthread_cond_wait( &cond, &mutex );
		pthread_mutex_unlock( &mutex );
	}
#endif

// --------------------------------------------------------------------------------------
//  Semaphore Implementations
// --------------------------------------------------------------------------------------

	Semaphore::Semaphore()
	{
		sem_init( &sema, false, 0 );
	}

	Semaphore::~Semaphore()
	{
		sem_destroy( &sema );
	}

	void Semaphore::Reset()
	{
		sem_destroy( &sema );
		sem_init( &sema, false, 0 );
	}

	void Semaphore::Post()
	{
		sem_post( &sema );
	}

	// Valid on Win32 builds only!!  Attempts to use it on Linux will result in unresolved
	// external linker errors.
	void Semaphore::Post( int multiple )
	{
#if defined(_MSC_VER)
		sem_post_multiple( &sema, multiple );
#else
		// Only w32pthreads has the post_multiple, but it's easy enough to fake:
		while( multiple > 0 )
		{
			multiple--;
			sem_post( &sema );
		}
#endif
	}

#if wxUSE_GUI
	// This is a wxApp-safe implementation of Wait, which makes sure and executes the App's
	// pending messages *if* the Wait is performed on the Main/GUI thread.  If the Wait is
	// called from another thread, no message pumping is performed.
	void Semaphore::WaitGui()
	{
		if( !wxThread::IsMain() || (wxTheApp == NULL) )
			Wait();
		else
		{
			// In order to avoid deadlock we need to make sure we cut some time
			// to handle messages.

			do {
				wxTheApp->Yield();
			} while( !Wait( ts_msec_250 ) );
		}
	}

	bool Semaphore::WaitGui( const wxTimeSpan& timeout )
	{
		if( !wxThread::IsMain() || (wxTheApp == NULL) )
		{
			return Wait( timeout );
		}
		else
		{
			wxTimeSpan countdown( (timeout) );

			// In order to avoid deadlock we need to make sure we cut some time
			// to handle messages.

			do {
				wxTheApp->Yield();
				if( Wait( ts_msec_250 ) ) break;
				countdown -= ts_msec_250;
			} while( countdown.GetMilliseconds() > 0 );

			return countdown.GetMilliseconds() > 0;
		}
	}
#endif

	void Semaphore::Wait()
	{
		sem_wait( &sema );
	}

	bool Semaphore::Wait( const wxTimeSpan& timeout )
	{
		wxDateTime megafail( wxDateTime::UNow() + timeout );
		const timespec fail = { megafail.GetTicks(), megafail.GetMillisecond() * 1000000 };
		return sem_timedwait( &sema, &fail ) != -1;
	}

	// Performs an uncancellable wait on a semaphore; restoring the thread's previous cancel state
	// after the wait has completed.  Useful for situations where the semaphore itself is stored on
	// the stack and passed to another thread via GUI message or such, avoiding complications where
	// the thread might be canceled and the stack value becomes invalid.
	//
	// Performance note: this function has quite a bit more overhead compared to Semaphore::Wait(), so
	// consider manually specifying the thread as uncancellable and using Wait() instead if you need
	// to do a lot of no-cancel waits in a tight loop worker thread, for example.
	void Semaphore::WaitNoCancel()
	{
		int oldstate;
		pthread_setcancelstate( PTHREAD_CANCEL_DISABLE, &oldstate );
		Wait();
		pthread_setcancelstate( oldstate, NULL );
	}

	int Semaphore::Count()
	{
		int retval;
		sem_getvalue( &sema, &retval );
		return retval;
	}

// --------------------------------------------------------------------------------------
//  MutexLock Implementations
// --------------------------------------------------------------------------------------

	MutexLock::MutexLock()
	{
		int err = 0;
		err = pthread_mutex_init( &mutex, NULL );
	}

	MutexLock::~MutexLock() throw()
	{
		pthread_mutex_destroy( &mutex );
	}

	static long _attr_refcount = 0;
	static pthread_mutexattr_t _attr_recursive;

	MutexLockRecursive::MutexLockRecursive() : MutexLock( false )
	{
		if( _InterlockedIncrement( &_attr_refcount ) == 1 )
		{
			if( 0 != pthread_mutexattr_init( &_attr_recursive ) )
				throw Exception::OutOfMemory( "Out of memory error initializing the Mutex attributes for recursive mutexing." );

			pthread_mutexattr_settype( &_attr_recursive, PTHREAD_MUTEX_RECURSIVE );
		}

		int err = 0;
		err = pthread_mutex_init( &mutex, &_attr_recursive );
	}

	MutexLockRecursive::~MutexLockRecursive() throw()
	{
		if( _InterlockedDecrement( &_attr_refcount ) == 0 )
			pthread_mutexattr_destroy( &_attr_recursive );
	}

	void MutexLock::Lock()
	{
		pthread_mutex_lock( &mutex );
	}

	void MutexLock::Unlock()
	{
		pthread_mutex_unlock( &mutex );
	}

	bool MutexLock::TryLock()
	{
		return EBUSY != pthread_mutex_trylock( &mutex );
	}

// --------------------------------------------------------------------------------------
//  InterlockedExchanges / AtomicExchanges (PCSX2's Helper versions)
// --------------------------------------------------------------------------------------
// define some overloads for InterlockedExchanges for commonly used types, like u32 and s32.

	__forceinline void AtomicExchange( volatile u32& Target, u32 value )
	{
		_InterlockedExchange( (volatile long*)&Target, value );
	}

	__forceinline void AtomicExchangeAdd( volatile u32& Target, u32 value )
	{
		_InterlockedExchangeAdd( (volatile long*)&Target, value );
	}

	__forceinline void AtomicIncrement( volatile u32& Target )
	{
		_InterlockedExchangeAdd( (volatile long*)&Target, 1 );
	}

	__forceinline void AtomicDecrement( volatile u32& Target )
	{
		_InterlockedExchangeAdd( (volatile long*)&Target, -1 );
	}

	__forceinline void AtomicExchange( volatile s32& Target, s32 value )
	{
		_InterlockedExchange( (volatile long*)&Target, value );
	}

	__forceinline void AtomicExchangeAdd( s32& Target, u32 value )
	{
		_InterlockedExchangeAdd( (volatile long*)&Target, value );
	}

	__forceinline void AtomicIncrement( volatile s32& Target )
	{
		_InterlockedExchangeAdd( (volatile long*)&Target, 1 );
	}

	__forceinline void AtomicDecrement( volatile s32& Target )
	{
		_InterlockedExchangeAdd( (volatile long*)&Target, -1 );
	}

	__forceinline void _AtomicExchangePointer( const void ** target, const void* value )
	{
		_InterlockedExchange( (volatile long*)target, (long)value );
	}

	__forceinline void _AtomicCompareExchangePointer( const void ** target, const void* value, const void* comparand )
	{
		_InterlockedCompareExchange( (volatile long*)target, (long)value, (long)comparand );
	}
}