/*-
 * Copyright (c) 2014-2018 MongoDB, Inc.
 * Copyright (c) 2008-2014 WiredTiger, Inc.
 *	All rights reserved.
 *
 * See the file LICENSE for redistribution information.
 */

#include "wt_internal.h"

/*
 * __wt_thread_create --
 *	Create a new thread of control.
 */
int
__wt_thread_create(WT_SESSION_IMPL *session,
    wt_thread_t *tidret, WT_THREAD_CALLBACK(*func)(void *), void *arg)
    WT_GCC_FUNC_ATTRIBUTE((visibility("default")))
{
	WT_DECL_RET;

	/*
	 * Creating a thread isn't a memory barrier, but WiredTiger commonly
	 * sets flags and or state and then expects worker threads to start.
	 * Include a barrier to ensure safety in those cases.
	 */
	WT_FULL_BARRIER();

	/* Spawn a new thread of control. */
	WT_SYSCALL_RETRY(pthread_create(&tidret->id, NULL, func, arg), ret);
	if (ret == 0) {
		tidret->created = true;
		return (0);
	}
	WT_RET_MSG(session, ret, "pthread_create");
}

/*
 * __wt_thread_join --
 *	Wait for a thread of control to exit.
 */
int
__wt_thread_join(WT_SESSION_IMPL *session, wt_thread_t tid)
    WT_GCC_FUNC_ATTRIBUTE((visibility("default")))
{
	WT_DECL_RET;

	/* Only attempt to join if thread was created successfully */
	if (!tid.created)
		return (0);

	/*
	 * Joining a thread isn't a memory barrier, but WiredTiger commonly
	 * sets flags and or state and then expects worker threads to halt.
	 * Include a barrier to ensure safety in those cases.
	 */
	WT_FULL_BARRIER();

	WT_SYSCALL(pthread_join(tid.id, NULL), ret);
	if (ret == 0) {
		tid.created = false;
		return (0);
	}

	WT_RET_MSG(session, ret, "pthread_join");
}

/*
 * __wt_thread_id --
 *	Return an arithmetic representation of a thread ID on POSIX.
 */
void
__wt_thread_id(uintmax_t *id)
    WT_GCC_FUNC_ATTRIBUTE((visibility("default")))
{
	pthread_t self;

	/*
	 * POSIX 1003.1 allows pthread_t to be an opaque type; on systems where
	 * it's a pointer, print the pointer to match gdb output.
	 */
	self = pthread_self();
#ifdef __sun
	*id = (uintmax_t)self;
#else
	*id = (uintmax_t)(void *)self;
#endif
}

/*
 * __wt_thread_str --
 *	Fill in a printable version of the process and thread IDs.
 */
int
__wt_thread_str(char *buf, size_t buflen)
    WT_GCC_FUNC_ATTRIBUTE((visibility("default")))
{
	pthread_t self;

	/*
	 * POSIX 1003.1 allows pthread_t to be an opaque type; on systems where
	 * it's a pointer, print the pointer to match gdb output.
	 */
	self = pthread_self();
#ifdef __sun
	return (__wt_snprintf(buf, buflen,
	    "%" PRIuMAX ":%u", (uintmax_t)getpid(), self));
#else
	return (__wt_snprintf(buf, buflen,
	    "%" PRIuMAX ":%p", (uintmax_t)getpid(), (void *)self));
#endif
}

/*
 * __wt_process_id --
 *      Return the process ID assigned by the operating system.
 */
uintmax_t
__wt_process_id(void)
{
	return ((uintmax_t)getpid());
}
