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/******************************************************
The interface to the operating system
synchronization primitives.
(c) 1995 Innobase Oy
Created 9/6/1995 Heikki Tuuri
*******************************************************/
#ifndef os0sync_h
#define os0sync_h
#include "univ.i"
#include "ut0lst.h"
#ifdef __WIN__
#define os_fast_mutex_t CRITICAL_SECTION
typedef HANDLE os_native_event_t;
typedef struct os_event_struct os_event_struct_t;
typedef os_event_struct_t* os_event_t;
struct os_event_struct {
os_native_event_t handle;
/* Windows event */
UT_LIST_NODE_T(os_event_struct_t) os_event_list;
/* list of all created events */
};
#else
typedef pthread_mutex_t os_fast_mutex_t;
typedef struct os_event_struct os_event_struct_t;
typedef os_event_struct_t* os_event_t;
struct os_event_struct {
os_fast_mutex_t os_mutex; /* this mutex protects the next
fields */
ibool is_set; /* this is TRUE when the event is
in the signaled state, i.e., a thread
does not stop if it tries to wait for
this event */
ib_longlong signal_count; /* this is incremented each time
the event becomes signaled */
pthread_cond_t cond_var; /* condition variable is used in
waiting for the event */
UT_LIST_NODE_T(os_event_struct_t) os_event_list;
/* list of all created events */
};
#endif
typedef struct os_mutex_struct os_mutex_str_t;
typedef os_mutex_str_t* os_mutex_t;
#define OS_SYNC_INFINITE_TIME ((ulint)(-1))
#define OS_SYNC_TIME_EXCEEDED 1
/* Mutex protecting counts and the event and OS 'slow' mutex lists */
extern os_mutex_t os_sync_mutex;
/* This is incremented by 1 in os_thread_create and decremented by 1 in
os_thread_exit */
extern ulint os_thread_count;
extern ulint os_event_count;
extern ulint os_mutex_count;
extern ulint os_fast_mutex_count;
/*************************************************************
Initializes global event and OS 'slow' mutex lists. */
void
os_sync_init(void);
/*==============*/
/*************************************************************
Frees created events and OS 'slow' mutexes. */
void
os_sync_free(void);
/*==============*/
/*************************************************************
Creates an event semaphore, i.e., a semaphore which may just have two states:
signaled and nonsignaled. The created event is manual reset: it must be reset
explicitly by calling sync_os_reset_event. */
os_event_t
os_event_create(
/*============*/
/* out: the event handle */
const char* name); /* in: the name of the event, if NULL
the event is created without a name */
#ifdef __WIN__
/*************************************************************
Creates an auto-reset event semaphore, i.e., an event which is automatically
reset when a single thread is released. Works only in Windows. */
os_event_t
os_event_create_auto(
/*=================*/
/* out: the event handle */
const char* name); /* in: the name of the event, if NULL
the event is created without a name */
#endif
/**************************************************************
Sets an event semaphore to the signaled state: lets waiting threads
proceed. */
void
os_event_set(
/*=========*/
os_event_t event); /* in: event to set */
/**************************************************************
Resets an event semaphore to the nonsignaled state. Waiting threads will
stop to wait for the event. */
void
os_event_reset(
/*===========*/
os_event_t event); /* in: event to reset */
/**************************************************************
Frees an event object. */
void
os_event_free(
/*==========*/
os_event_t event); /* in: event to free */
/**************************************************************
Waits for an event object until it is in the signaled state. If
srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS this also exits the
waiting thread when the event becomes signaled (or immediately if the
event is already in the signaled state). */
void
os_event_wait(
/*==========*/
os_event_t event); /* in: event to wait */
/**************************************************************
Waits for an event object until it is in the signaled state or
a timeout is exceeded. In Unix the timeout is always infinite. */
ulint
os_event_wait_time(
/*===============*/
/* out: 0 if success,
OS_SYNC_TIME_EXCEEDED if timeout
was exceeded */
os_event_t event, /* in: event to wait */
ulint time); /* in: timeout in microseconds, or
OS_SYNC_INFINITE_TIME */
#ifdef __WIN__
/**************************************************************
Waits for any event in an OS native event array. Returns if even a single
one is signaled or becomes signaled. */
ulint
os_event_wait_multiple(
/*===================*/
/* out: index of the event
which was signaled */
ulint n, /* in: number of events in the
array */
os_native_event_t* native_event_array);
/* in: pointer to an array of event
handles */
#endif
/*************************************************************
Creates an operating system mutex semaphore. Because these are slow, the
mutex semaphore of InnoDB itself (mutex_t) should be used where possible. */
os_mutex_t
os_mutex_create(
/*============*/
/* out: the mutex handle */
const char* name); /* in: the name of the mutex, if NULL
the mutex is created without a name */
/**************************************************************
Acquires ownership of a mutex semaphore. */
void
os_mutex_enter(
/*===========*/
os_mutex_t mutex); /* in: mutex to acquire */
/**************************************************************
Releases ownership of a mutex. */
void
os_mutex_exit(
/*==========*/
os_mutex_t mutex); /* in: mutex to release */
/**************************************************************
Frees an mutex object. */
void
os_mutex_free(
/*==========*/
os_mutex_t mutex); /* in: mutex to free */
/**************************************************************
Acquires ownership of a fast mutex. Currently in Windows this is the same
as os_fast_mutex_lock! */
UNIV_INLINE
ulint
os_fast_mutex_trylock(
/*==================*/
/* out: 0 if success, != 0 if
was reserved by another
thread */
os_fast_mutex_t* fast_mutex); /* in: mutex to acquire */
/**************************************************************
Releases ownership of a fast mutex. */
void
os_fast_mutex_unlock(
/*=================*/
os_fast_mutex_t* fast_mutex); /* in: mutex to release */
/*************************************************************
Initializes an operating system fast mutex semaphore. */
void
os_fast_mutex_init(
/*===============*/
os_fast_mutex_t* fast_mutex); /* in: fast mutex */
/**************************************************************
Acquires ownership of a fast mutex. */
void
os_fast_mutex_lock(
/*===============*/
os_fast_mutex_t* fast_mutex); /* in: mutex to acquire */
/**************************************************************
Frees an mutex object. */
void
os_fast_mutex_free(
/*===============*/
os_fast_mutex_t* fast_mutex); /* in: mutex to free */
#ifndef UNIV_NONINL
#include "os0sync.ic"
#endif
#endif
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