Modules/threadmodule.c

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
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/* Thread module */
/* Interface to Sjoerd's portable C thread library */

#include "allobjects.h"

#ifndef WITH_THREAD
Error!  The rest of Python is not compiled with thread support.
Rerun configure, adding a --with-thread option.
#endif

#include "thread.h"

extern int threads_started;

static object *ThreadError;


/* Lock objects */

typedef struct {
	OB_HEAD
	type_lock lock_lock;
} lockobject;

staticforward typeobject Locktype;

#define is_lockobject(v)		((v)->ob_type == &Locktype)

type_lock
getlocklock(lock)
	object *lock;
{
	if (lock == NULL || !is_lockobject(lock))
		return NULL;
	else
		return ((lockobject *) lock)->lock_lock;
}

static lockobject *
newlockobject()
{
	lockobject *self;
	self = NEWOBJ(lockobject, &Locktype);
	if (self == NULL)
		return NULL;
	self->lock_lock = allocate_lock();
	if (self->lock_lock == NULL) {
		DEL(self);
		self = NULL;
		err_setstr(ThreadError, "can't allocate lock");
	}
	return self;
}

static void
lock_dealloc(self)
	lockobject *self;
{
	/* Unlock the lock so it's safe to free it */
	acquire_lock(self->lock_lock, 0);
	release_lock(self->lock_lock);
	
	free_lock(self->lock_lock);
	DEL(self);
}

static object *
lock_acquire_lock(self, args)
	lockobject *self;
	object *args;
{
	int i;

	if (args != NULL) {
		if (!getargs(args, "i", &i))
			return NULL;
	}
	else
		i = 1;

	BGN_SAVE
	i = acquire_lock(self->lock_lock, i);
	END_SAVE

	if (args == NULL) {
		INCREF(None);
		return None;
	}
	else
		return newintobject((long)i);
}

static object *
lock_release_lock(self, args)
	lockobject *self;
	object *args;
{
	if (!getnoarg(args))
		return NULL;

	/* Sanity check: the lock must be locked */
	if (acquire_lock(self->lock_lock, 0)) {
		release_lock(self->lock_lock);
		err_setstr(ThreadError, "release unlocked lock");
		return NULL;
	}

	release_lock(self->lock_lock);
	INCREF(None);
	return None;
}

static object *
lock_locked_lock(self, args)
	lockobject *self;
	object *args;
{
	if (!getnoarg(args))
		return NULL;

	if (acquire_lock(self->lock_lock, 0)) {
		release_lock(self->lock_lock);
		return newintobject(0L);
	}
	return newintobject(1L);
}

static struct methodlist lock_methods[] = {
	{"acquire_lock",	(method)lock_acquire_lock},
	{"acquire",		(method)lock_acquire_lock},
	{"release_lock",	(method)lock_release_lock},
	{"release",		(method)lock_release_lock},
	{"locked_lock",		(method)lock_locked_lock},
	{"locked",		(method)lock_locked_lock},
	{NULL,			NULL}		/* sentinel */
};

static object *
lock_getattr(self, name)
	lockobject *self;
	char *name;
{
	return findmethod(lock_methods, (object *)self, name);
}

static typeobject Locktype = {
	OB_HEAD_INIT(&Typetype)
	0,				/*ob_size*/
	"lock",				/*tp_name*/
	sizeof(lockobject),		/*tp_size*/
	0,				/*tp_itemsize*/
	/* methods */
	(destructor)lock_dealloc,	/*tp_dealloc*/
	0,				/*tp_print*/
	(getattrfunc)lock_getattr,	/*tp_getattr*/
	0,				/*tp_setattr*/
	0,				/*tp_compare*/
	0,				/*tp_repr*/
};


/* Module functions */

static void
t_bootstrap(args_raw)
	void *args_raw;
{
	object *args = (object *) args_raw;
	object *func, *arg, *res;

	threads_started++;

	restore_thread((void *)NULL);
	func = gettupleitem(args, 0);
	arg = gettupleitem(args, 1);
	res = call_object(func, arg);
	DECREF(args); /* Matches the INCREF(args) in thread_start_new_thread */
	if (res == NULL) {
		if (err_occurred() == SystemExit)
			err_clear();
		else {
			fprintf(stderr, "Unhandled exception in thread:\n");
			print_error(); /* From pythonmain.c */
		}
	}
	else
		DECREF(res);
	(void) save_thread(); /* Should always be NULL */
	exit_thread();
}

static object *
thread_start_new_thread(self, args)
	object *self; /* Not used */
	object *args;
{
	object *func, *arg;

	if (!getargs(args, "(OO)", &func, &arg))
		return NULL;
	INCREF(args);
	/* Initialize the interpreter's stack save/restore mechanism */
	init_save_thread();
	if (!start_new_thread(t_bootstrap, (void*) args)) {
		DECREF(args);
		err_setstr(ThreadError, "can't start new thread\n");
		return NULL;
	}
	/* Otherwise the DECREF(args) is done by t_bootstrap */
	INCREF(None);
	return None;
}

static object *
thread_exit_thread(self, args)
	object *self; /* Not used */
	object *args;
{
	if (!getnoarg(args))
		return NULL;
	err_set(SystemExit);
	return NULL;
}

#ifndef NO_EXIT_PROG
static object *
thread_exit_prog(self, args)
	object *self; /* Not used */
	object *args;
{
	int sts;
	if (!getargs(args, "i", &sts))
		return NULL;
	goaway(sts); /* Calls exit_prog(sts) or _exit_prog(sts) */
	for (;;) { } /* Should not be reached */
}
#endif

static object *
thread_allocate_lock(self, args)
	object *self; /* Not used */
	object *args;
{
	if (!getnoarg(args))
		return NULL;
	return (object *) newlockobject();
}

static object *
thread_get_ident(self, args)
	object *self; /* Not used */
	object *args;
{
	long ident;
	if (!getnoarg(args))
		return NULL;
	ident = get_thread_ident();
	if (ident == -1) {
		err_setstr(ThreadError, "no current thread ident");
		return NULL;
	}
	return newintobject(ident);
}

static struct methodlist thread_methods[] = {
	{"start_new_thread",	(method)thread_start_new_thread},
	{"start_new",		(method)thread_start_new_thread},
	{"allocate_lock",	(method)thread_allocate_lock},
	{"allocate",		(method)thread_allocate_lock},
	{"exit_thread",		(method)thread_exit_thread},
	{"exit",		(method)thread_exit_thread},
	{"get_ident",		(method)thread_get_ident},
#ifndef NO_EXIT_PROG
	{"exit_prog",		(method)thread_exit_prog},
#endif
	{NULL,			NULL}		/* sentinel */
};


/* Initialization function */

void
initthread()
{
	object *m, *d;

	/* Create the module and add the functions */
	m = initmodule("thread", thread_methods);

	/* Add a symbolic constant */
	d = getmoduledict(m);
	ThreadError = newstringobject("thread.error");
	INCREF(ThreadError);
	dictinsert(d, "error", ThreadError);

	/* Check for errors */
	if (err_occurred())
		fatal("can't initialize module thread");

	/* Initialize the C thread library */
	init_thread();
}