cpython/Python/thread.c

/* Thread package.
   This is intended to be usable independently from Python.
   The implementation for system foobar is in a file thread_foobar.h
   which is included by this file dependent on config settings.
   Stuff shared by all thread_*.h files is collected here. */

#include "Python.h"


#ifndef _POSIX_THREADS
/* This means pthreads are not implemented in libc headers, hence the macro
   not present in unistd.h. But they still can be implemented as an external
   library (e.g. gnu pth in pthread emulation) */
# ifdef HAVE_PTHREAD_H
#  include <pthread.h> /* _POSIX_THREADS */
# endif
#endif

#ifndef DONT_HAVE_STDIO_H
#include <stdio.h>
#endif

#include <stdlib.h>

#ifdef __sgi
#ifndef HAVE_PTHREAD_H /* XXX Need to check in configure.in */
#undef _POSIX_THREADS
#endif
#endif

#include "pythread.h"

#ifndef _POSIX_THREADS

#ifdef __sgi
#define SGI_THREADS
#endif

#ifdef HAVE_THREAD_H
#define SOLARIS_THREADS
#endif

#if defined(sun) && !defined(SOLARIS_THREADS)
#define SUN_LWP
#endif

#endif /* _POSIX_THREADS */


#ifdef Py_DEBUG
static int thread_debug = 0;
#define dprintf(args)	(void)((thread_debug & 1) && printf args)
#define d2printf(args)	((thread_debug & 8) && printf args)
#else
#define dprintf(args)
#define d2printf(args)
#endif

static int initialized;

static void PyThread__init_thread(void); /* Forward */

void PyThread_init_thread(void)
{
#ifdef Py_DEBUG
	char *p = getenv("THREADDEBUG");

	if (p) {
		if (*p)
			thread_debug = atoi(p);
		else
			thread_debug = 1;
	}
#endif /* Py_DEBUG */
	if (initialized)
		return;
	initialized = 1;
	dprintf(("PyThread_init_thread called\n"));
	PyThread__init_thread();
}

#ifdef SGI_THREADS
#include "thread_sgi.h"
#endif

#ifdef SOLARIS_THREADS
#include "thread_solaris.h"
#endif

#ifdef SUN_LWP
#include "thread_lwp.h"
#endif

#ifdef HAVE_PTH
#include "thread_pth.h"
#undef _POSIX_THREADS
#endif

#ifdef _POSIX_THREADS
#include "thread_pthread.h"
#endif

#ifdef C_THREADS
#include "thread_cthread.h"
#endif

#ifdef NT_THREADS
#include "thread_nt.h"
#endif

#ifdef OS2_THREADS
#include "thread_os2.h"
#endif

#ifdef BEOS_THREADS
#include "thread_beos.h"
#endif

#ifdef WINCE_THREADS
#include "thread_wince.h"
#endif

#ifdef PLAN9_THREADS
#include "thread_plan9.h"
#endif

#ifdef ATHEOS_THREADS
#include "thread_atheos.h"
#endif

/*
#ifdef FOOBAR_THREADS
#include "thread_foobar.h"
#endif
*/

#ifndef Py_HAVE_NATIVE_TLS
/* If the platform has not supplied a platform specific
   TLS implementation, provide our own.

   This code stolen from "thread_sgi.h", where it was the only
   implementation of an existing Python TLS API.
*/
/*
 * Per-thread data ("key") support.
 */

struct key {
	struct key *next;
	long id;
	int key;
	void *value;
};

static struct key *keyhead = NULL;
static int nkeys = 0;
static PyThread_type_lock keymutex = NULL;

static struct key *
find_key(int key, void *value)
{
	struct key *p;
	long id = PyThread_get_thread_ident();
	for (p = keyhead; p != NULL; p = p->next) {
		if (p->id == id && p->key == key)
			return p;
	}
	if (value == NULL)
		return NULL;
	p = (struct key *)malloc(sizeof(struct key));
	if (p != NULL) {
		p->id = id;
		p->key = key;
		p->value = value;
		PyThread_acquire_lock(keymutex, 1);
		p->next = keyhead;
		keyhead = p;
		PyThread_release_lock(keymutex);
	}
	return p;
}

int
PyThread_create_key(void)
{
	if (keymutex == NULL)
		keymutex = PyThread_allocate_lock();
	return ++nkeys;
}

void
PyThread_delete_key(int key)
{
	struct key *p, **q;
	PyThread_acquire_lock(keymutex, 1);
	q = &keyhead;
	while ((p = *q) != NULL) {
		if (p->key == key) {
			*q = p->next;
			free((void *)p);
			/* NB This does *not* free p->value! */
		}
		else
			q = &p->next;
	}
	PyThread_release_lock(keymutex);
}

int
PyThread_set_key_value(int key, void *value)
{
	struct key *p = find_key(key, value);
	if (p == NULL)
		return -1;
	else
		return 0;
}

void *
PyThread_get_key_value(int key)
{
	struct key *p = find_key(key, NULL);
	if (p == NULL)
		return NULL;
	else
		return p->value;
}

void
PyThread_delete_key_value(int key)
{
	long id = PyThread_get_thread_ident();
	struct key *p, **q;
	PyThread_acquire_lock(keymutex, 1);
	q = &keyhead;
	while ((p = *q) != NULL) {
		if (p->key == key && p->id == id) {
			*q = p->next;
			free((void *)p);
			/* NB This does *not* free p->value! */
			break;
		}
		else
			q = &p->next;
	}
	PyThread_release_lock(keymutex);
}

#endif /* Py_HAVE_NATIVE_TLS */