//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// thread.c --
//
// Author           : Thierry Delisle
// Created On       : Tue Jan 17 12:27:26 2017
// Last Modified By : Peter A. Buhr
// Last Modified On : Wed Nov 30 18:14:07 2022
// Update Count     : 95
//

#define __cforall_thread__
#define _GNU_SOURCE

#include "thread.hfa"

#include "exception.hfa"
#include "kernel/private.hfa"
#include "limits.hfa"

#define __CFA_INVOKE_PRIVATE__
#include "invoke.h"

extern size_t __global_random_seed;
extern size_t __global_random_prime;
extern bool __global_random_mask;

#pragma GCC visibility push(default)

//-----------------------------------------------------------------------------
// Thread ctors and dtors
void ?{}( thread$ & this, const char * const name, cluster & cl, void * storage, size_t storageSize ) with( this ) {
	context{ 0p, 0p };
	self_cor{ name, storage, storageSize };
	ticket = TICKET_RUNNING;
	state = Start;
	preempted = __NO_PREEMPTION;
	corctx_flag = false;
	curr_cor = &self_cor;
	self_mon.owner = &this;
	self_mon.recursion = 1;
	self_mon_p = &self_mon;
	curr_cluster = &cl;
	rdy_link.next = 0p;
	rdy_link.ts   = MAX;
	user_link.next = 0p;
	user_link.prev = 0p;
	cltr_link.next = 0p;
	cltr_link.prev = 0p;
	preferred = ready_queue_new_preferred();
	last_proc = 0p;
	PRNG_SET_SEED( random_state, __global_random_mask ? __global_random_prime : __global_random_prime ^ rdtscl() );
	#if defined( __CFA_WITH_VERIFY__ )
		executing = 0p;
		canary = 0x0D15EA5E0D15EA5Ep;
	#endif

	clh_node = malloc( );
	*clh_node = false;

	doregister(curr_cluster, this);
	monitors{ &self_mon_p, 1, (fptr_t)0 };
}

void ^?{}(thread$& this) with( this ) {
	#if defined( __CFA_WITH_VERIFY__ )
		canary = 0xDEADDEADDEADDEADp;
	#endif
	free(clh_node);
	unregister(curr_cluster, this);
	^self_cor{};
}

forall(T &)
void copy(ThreadCancelled(T) * dst, ThreadCancelled(T) * src) {
	dst->virtual_table = src->virtual_table;
	dst->the_thread = src->the_thread;
	dst->the_exception = src->the_exception;
}

forall(T &)
const char * msg(ThreadCancelled(T) *) {
	return "ThreadCancelled(...)";
}

forall(T &)
static void default_thread_cancel_handler(ThreadCancelled(T) & ) {
	// Improve this error message, can I do formatting?
	abort( "Unhandled thread cancellation.\n" );
}

forall(T & | is_thread(T) | IS_EXCEPTION(ThreadCancelled(T))
    | { EHM_DEFAULT_VTABLE(ThreadCancelled(T)); })
void ?{}( thread_dtor_guard_t & this,
		T & thrd, void(*cancelHandler)(ThreadCancelled(T) &)) {
	monitor$ * m = get_monitor(thrd);
	thread$ * desc = get_thread(thrd);

	// Setup the monitor guard
	void (*dtor)(T& mutex this) = ^?{};
	bool join = cancelHandler != (void(*)(ThreadCancelled(T)&))0;
	(this.mg){&m, (void(*)())dtor, join};


	/* paranoid */ verifyf( Halted == desc->state || Cancelled == desc->state, "Expected thread to be Halted or Cancelled, was %d\n", (int)desc->state );

	// After the guard set-up and any wait, check for cancellation.
	struct _Unwind_Exception * cancellation = desc->self_cor.cancellation;
	if ( likely( 0p == cancellation ) ) {
		return;
	} else if ( Cancelled == desc->state ) {
		return;
	}
	desc->state = Cancelled;
	void(*defaultResumptionHandler)(ThreadCancelled(T) &) =
		join ? cancelHandler : default_thread_cancel_handler;

	// TODO: Remove explitate vtable set once trac#186 is fixed.
	ThreadCancelled(T) except;
	except.virtual_table = &_default_vtable;
	except.the_thread = &thrd;
	except.the_exception = __cfaehm_cancellation_exception( cancellation );
	// Why is this cast required?
	throwResume (ThreadCancelled(T) &)except;

	except.the_exception->virtual_table->free( except.the_exception );
	free( cancellation );
	desc->self_cor.cancellation = 0p;
}

void ^?{}( thread_dtor_guard_t & this ) {
	^(this.mg){};
}

//-----------------------------------------------------------------------------
// Starting and stopping threads
forall( T & | is_thread(T) )
void __thrd_start( T & this, void (*main_p)(T &) ) {
	thread$ * this_thrd = get_thread(this);

	disable_interrupts();
	__cfactx_start(main_p, get_coroutine(this), this, __cfactx_invoke_thread);

	this_thrd->context.[SP, FP] = this_thrd->self_cor.context.[SP, FP];
	/* paranoid */ verify( this_thrd->context.SP );

	schedule_thread$( this_thrd, UNPARK_LOCAL );
	enable_interrupts();
}

//-----------------------------------------------------------------------------
// Support for threads that don't ues the thread keyword
forall( T & | sized(T) | is_thread(T) | { void ?{}(T&); } )
void ?{}( scoped(T)& this ) with( this ) {
	handle{};
	__thrd_start(handle, main);
}

forall( T &, P... | sized(T) | is_thread(T) | { void ?{}(T&, P); } )
void ?{}( scoped(T)& this, P params ) with( this ) {
	handle{ params };
	__thrd_start(handle, main);
}

forall( T & | sized(T) | is_thread(T) )
void ^?{}( scoped(T)& this ) with( this ) {
	^handle{};
}

//-----------------------------------------------------------------------------
forall(T & | is_thread(T) | IS_RESUMPTION_EXCEPTION(ThreadCancelled(T))
	| { EHM_DEFAULT_VTABLE(ThreadCancelled(T)); })
T & join( T & this ) {
	thread_dtor_guard_t guard = { this, defaultResumptionHandler };
	return this;
}

//-----------------------------------------------------------------------------
bool migrate( thread$ * thrd, struct cluster & cl ) {

	monitor$ * tmon = get_monitor(thrd);
	monitor$ * __monitors[] = { tmon };
	monitor_guard_t __guard = { __monitors, 1 };


	{
		// if nothing needs to be done, return false
		if( thrd->curr_cluster == &cl ) return false;

		// are we migrating ourself?
		const bool local = thrd == active_thread();

		/* paranoid */ verify( !local || &cl != active_cluster() );
		/* paranoid */ verify( !local || thrd->curr_cluster == active_cluster() );
		/* paranoid */ verify( !local || thrd->curr_cluster == active_processor()->cltr );
		/* paranoid */ verify( local || tmon->signal_stack.top->owner->waiting_thread == thrd );
		/* paranoid */ verify( local || tmon->signal_stack.top );

		// make sure we aren't interrupted while doing this
		// not as important if we aren't local
		disable_interrupts();

		// actually move the thread
		unregister( thrd->curr_cluster, *thrd );
		thrd->curr_cluster = &cl;
		doregister( thrd->curr_cluster, *thrd );

		// restore interrupts
		enable_interrupts();

		// if this is the local thread, we are still running on the old cluster
		if(local) yield();

		/* paranoid */ verify( !local || &cl == active_cluster() );
		/* paranoid */ verify( !local || thrd->curr_cluster == active_cluster() );
		/* paranoid */ verify( !local || thrd->curr_cluster == active_processor()->cltr );
		/* paranoid */ verify(  local || tmon->signal_stack.top );
		/* paranoid */ verify(  local || tmon->signal_stack.top->owner->waiting_thread == thrd );

		return true;
	}
}

//-----------------------------------------------------------------------------

void set_seed( size_t seed ) {
	PRNG_STATE_T & state = active_thread()->random_state;
	__global_random_seed = seed;
	PRNG_SET_SEED( state, seed );
	(void)PRNG_NAME( state );							// prime PRNG
	__global_random_prime = seed;
	__global_random_mask = true;
} // set_seed

size_t prng( void ) {									// [0,UINT_MAX]
	PRNG_STATE_T( & state ) = active_thread()->random_state;
	return PRNG_NAME( state );
} // prng

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