#if !defined __lanes_private_h__
#define __lanes_private_h__ 1

#include "uniquekey.h"

/*
 * Lane cancellation request modes
 */
enum e_cancel_request
{
	CANCEL_NONE, // no pending cancel request
	CANCEL_SOFT, // user wants the lane to cancel itself manually on cancel_test()
	CANCEL_HARD  // user wants the lane to be interrupted (meaning code won't return from those functions) from inside linda:send/receive calls
};

// NOTE: values to be changed by either thread, during execution, without
//       locking, are marked "volatile"
//
struct s_Lane
{
	THREAD_T thread;
	//
	// M: sub-thread OS thread
	// S: not used

	char const* debug_name;

	lua_State* L;
	Universe* U;
	//
	// M: prepares the state, and reads results
	// S: while S is running, M must keep out of modifying the state

	volatile enum e_status status;
	// 
	// M: sets to PENDING (before launching)
	// S: updates -> RUNNING/WAITING -> DONE/ERROR_ST/CANCELLED

	SIGNAL_T* volatile waiting_on;
	//
	// When status is WAITING, points on the linda's signal the thread waits on, else NULL

	volatile enum e_cancel_request cancel_request;
	//
	// M: sets to FALSE, flags TRUE for cancel request
	// S: reads to see if cancel is requested

#if THREADWAIT_METHOD == THREADWAIT_CONDVAR
	SIGNAL_T done_signal;
	//
	// M: Waited upon at lane ending  (if Posix with no PTHREAD_TIMEDJOIN)
	// S: sets the signal once cancellation is noticed (avoids a kill)

	MUTEX_T done_lock;
	// 
	// Lock required by 'done_signal' condition variable, protecting
	// lane status changes to DONE/ERROR_ST/CANCELLED.
#endif // THREADWAIT_METHOD == THREADWAIT_CONDVAR

	volatile enum
	{
		NORMAL,         // normal master side state
		KILLED          // issued an OS kill
	} mstatus;
	//
	// M: sets to NORMAL, if issued a kill changes to KILLED
	// S: not used

	struct s_Lane* volatile selfdestruct_next;
	//
	// M: sets to non-NULL if facing lane handle '__gc' cycle but the lane
	//    is still running
	// S: cleans up after itself if non-NULL at lane exit

#if HAVE_LANE_TRACKING
	struct s_Lane* volatile tracking_next;
#endif // HAVE_LANE_TRACKING
	//
	// For tracking only
};
typedef struct s_Lane Lane;

// To allow free-running threads (longer lifespan than the handle's)
// 'Lane' are malloc/free'd and the handle only carries a pointer.
// This is not deep userdata since the handle's not portable among lanes.
//
#define lua_toLane( L, i) (*((Lane**) luaL_checkudata( L, i, "Lane")))

// crc64/we of string "CANCEL_ERROR" generated at http://www.nitrxgen.net/hashgen/
static DECLARE_CONST_UNIQUE_KEY(CANCEL_ERROR, 0xe97d41626cc97577); // 'cancel_error' sentinel

// crc64/we of string "CANCEL_TEST_KEY" generated at http://www.nitrxgen.net/hashgen/
static DECLARE_CONST_UNIQUE_KEY(CANCEL_TEST_KEY, 0xe66f5960c57d133a); // used as registry key

static inline Lane* get_lane_from_registry( lua_State* L)
{
	Lane* s;
	STACK_GROW( L, 1);
	STACK_CHECK( L, 0);
	REGISTRY_GET( L, CANCEL_TEST_KEY);
	s = lua_touserdata( L, -1);     // lightuserdata (true 's_lane' pointer) / nil
	lua_pop( L, 1);
	STACK_END( L, 0);
	return s;
}

static inline int cancel_error( lua_State* L)
{
	STACK_GROW( L, 1);
	push_unique_key( L, CANCEL_ERROR); // special error value
	return lua_error( L); // doesn't return
}

#endif // __lanes_private_h__