Staging
v0.5.1
https://github.com/python/cpython
Revision d89cea15ad37e873003fc74ec2c77660ab620b00 authored by Daniel Andersson on 13 November 2019, 09:03:45 UTC, committed by Vinay Sajip on 13 November 2019, 09:03:45 UTC
This makes it easier to use a custom buffer when subclassing
MemoryHandler (by avoiding the explicity empty list literal
assignment in the flush method). For example, collection.deque
can now be used without any modifications to MemoryHandler.flush.

The same applies to BufferingHandler.
1 parent 9c28449
Raw File
Tip revision: d89cea15ad37e873003fc74ec2c77660ab620b00 authored by Daniel Andersson on 13 November 2019, 09:03:45 UTC
bpo-38781: Clear buffer in MemoryHandler flush (GH-17132)
Tip revision: d89cea1
thread_pthread.h

/* Posix threads interface */

#include <stdlib.h>
#include <string.h>
#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)
#define destructor xxdestructor
#endif
#include <pthread.h>
#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)
#undef destructor
#endif
#include <signal.h>

#if defined(__linux__)
#   include <sys/syscall.h>     /* syscall(SYS_gettid) */
#elif defined(__FreeBSD__)
#   include <pthread_np.h>      /* pthread_getthreadid_np() */
#elif defined(__OpenBSD__)
#   include <unistd.h>          /* getthrid() */
#elif defined(_AIX)
#   include <sys/thread.h>      /* thread_self() */
#elif defined(__NetBSD__)
#   include <lwp.h>             /* _lwp_self() */
#endif

/* The POSIX spec requires that use of pthread_attr_setstacksize
   be conditional on _POSIX_THREAD_ATTR_STACKSIZE being defined. */
#ifdef _POSIX_THREAD_ATTR_STACKSIZE
#ifndef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE       0       /* use default stack size */
#endif

/* The default stack size for new threads on OSX and BSD is small enough that
 * we'll get hard crashes instead of 'maximum recursion depth exceeded'
 * exceptions.
 *
 * The default stack sizes below are the empirically determined minimal stack
 * sizes where a simple recursive function doesn't cause a hard crash.
 */
#if defined(__APPLE__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef  THREAD_STACK_SIZE
/* Note: This matches the value of -Wl,-stack_size in configure.ac */
#define THREAD_STACK_SIZE       0x1000000
#endif
#if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef  THREAD_STACK_SIZE
#define THREAD_STACK_SIZE       0x400000
#endif
#if defined(_AIX) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef  THREAD_STACK_SIZE
#define THREAD_STACK_SIZE       0x200000
#endif
/* for safety, ensure a viable minimum stacksize */
#define THREAD_STACK_MIN        0x8000  /* 32 KiB */
#else  /* !_POSIX_THREAD_ATTR_STACKSIZE */
#ifdef THREAD_STACK_SIZE
#error "THREAD_STACK_SIZE defined but _POSIX_THREAD_ATTR_STACKSIZE undefined"
#endif
#endif

/* The POSIX spec says that implementations supporting the sem_*
   family of functions must indicate this by defining
   _POSIX_SEMAPHORES. */
#ifdef _POSIX_SEMAPHORES
/* On FreeBSD 4.x, _POSIX_SEMAPHORES is defined empty, so
   we need to add 0 to make it work there as well. */
#if (_POSIX_SEMAPHORES+0) == -1
#define HAVE_BROKEN_POSIX_SEMAPHORES
#else
#include <semaphore.h>
#include <errno.h>
#endif
#endif


/* Whether or not to use semaphores directly rather than emulating them with
 * mutexes and condition variables:
 */
#if (defined(_POSIX_SEMAPHORES) && !defined(HAVE_BROKEN_POSIX_SEMAPHORES) && \
     defined(HAVE_SEM_TIMEDWAIT))
#  define USE_SEMAPHORES
#else
#  undef USE_SEMAPHORES
#endif


/* On platforms that don't use standard POSIX threads pthread_sigmask()
 * isn't present.  DEC threads uses sigprocmask() instead as do most
 * other UNIX International compliant systems that don't have the full
 * pthread implementation.
 */
#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)
#  define SET_THREAD_SIGMASK pthread_sigmask
#else
#  define SET_THREAD_SIGMASK sigprocmask
#endif


#define MICROSECONDS_TO_TIMESPEC(microseconds, ts) \
do { \
    struct timeval tv; \
    gettimeofday(&tv, NULL); \
    tv.tv_usec += microseconds % 1000000; \
    tv.tv_sec += microseconds / 1000000; \
    tv.tv_sec += tv.tv_usec / 1000000; \
    tv.tv_usec %= 1000000; \
    ts.tv_sec = tv.tv_sec; \
    ts.tv_nsec = tv.tv_usec * 1000; \
} while(0)


/*
 * pthread_cond support
 */

#if defined(HAVE_PTHREAD_CONDATTR_SETCLOCK) && defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
// monotonic is supported statically.  It doesn't mean it works on runtime.
#define CONDATTR_MONOTONIC
#endif

// NULL when pthread_condattr_setclock(CLOCK_MONOTONIC) is not supported.
static pthread_condattr_t *condattr_monotonic = NULL;

static void
init_condattr()
{
#ifdef CONDATTR_MONOTONIC
    static pthread_condattr_t ca;
    pthread_condattr_init(&ca);
    if (pthread_condattr_setclock(&ca, CLOCK_MONOTONIC) == 0) {
        condattr_monotonic = &ca;  // Use monotonic clock
    }
#endif
}

int
_PyThread_cond_init(PyCOND_T *cond)
{
    return pthread_cond_init(cond, condattr_monotonic);
}

void
_PyThread_cond_after(long long us, struct timespec *abs)
{
#ifdef CONDATTR_MONOTONIC
    if (condattr_monotonic) {
        clock_gettime(CLOCK_MONOTONIC, abs);
        abs->tv_sec  += us / 1000000;
        abs->tv_nsec += (us % 1000000) * 1000;
        abs->tv_sec  += abs->tv_nsec / 1000000000;
        abs->tv_nsec %= 1000000000;
        return;
    }
#endif

    struct timespec ts;
    MICROSECONDS_TO_TIMESPEC(us, ts);
    *abs = ts;
}


/* A pthread mutex isn't sufficient to model the Python lock type
 * because, according to Draft 5 of the docs (P1003.4a/D5), both of the
 * following are undefined:
 *  -> a thread tries to lock a mutex it already has locked
 *  -> a thread tries to unlock a mutex locked by a different thread
 * pthread mutexes are designed for serializing threads over short pieces
 * of code anyway, so wouldn't be an appropriate implementation of
 * Python's locks regardless.
 *
 * The pthread_lock struct implements a Python lock as a "locked?" bit
 * and a <condition, mutex> pair.  In general, if the bit can be acquired
 * instantly, it is, else the pair is used to block the thread until the
 * bit is cleared.     9 May 1994 tim@ksr.com
 */

typedef struct {
    char             locked; /* 0=unlocked, 1=locked */
    /* a <cond, mutex> pair to handle an acquire of a locked lock */
    pthread_cond_t   lock_released;
    pthread_mutex_t  mut;
} pthread_lock;

#define CHECK_STATUS(name)  if (status != 0) { perror(name); error = 1; }
#define CHECK_STATUS_PTHREAD(name)  if (status != 0) { fprintf(stderr, \
    "%s: %s\n", name, strerror(status)); error = 1; }

/*
 * Initialization.
 */
static void
PyThread__init_thread(void)
{
#if defined(_AIX) && defined(__GNUC__)
    extern void pthread_init(void);
    pthread_init();
#endif
    init_condattr();
}

/*
 * Thread support.
 */

/* bpo-33015: pythread_callback struct and pythread_wrapper() cast
   "void func(void *)" to "void* func(void *)": always return NULL.

   PyThread_start_new_thread() uses "void func(void *)" type, whereas
   pthread_create() requires a void* return value. */
typedef struct {
    void (*func) (void *);
    void *arg;
} pythread_callback;

static void *
pythread_wrapper(void *arg)
{
    /* copy func and func_arg and free the temporary structure */
    pythread_callback *callback = arg;
    void (*func)(void *) = callback->func;
    void *func_arg = callback->arg;
    PyMem_RawFree(arg);

    func(func_arg);
    return NULL;
}

unsigned long
PyThread_start_new_thread(void (*func)(void *), void *arg)
{
    pthread_t th;
    int status;
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    pthread_attr_t attrs;
#endif
#if defined(THREAD_STACK_SIZE)
    size_t      tss;
#endif

    dprintf(("PyThread_start_new_thread called\n"));
    if (!initialized)
        PyThread_init_thread();

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    if (pthread_attr_init(&attrs) != 0)
        return PYTHREAD_INVALID_THREAD_ID;
#endif
#if defined(THREAD_STACK_SIZE)
    PyThreadState *tstate = _PyThreadState_GET();
    size_t stacksize = tstate ? tstate->interp->pythread_stacksize : 0;
    tss = (stacksize != 0) ? stacksize : THREAD_STACK_SIZE;
    if (tss != 0) {
        if (pthread_attr_setstacksize(&attrs, tss) != 0) {
            pthread_attr_destroy(&attrs);
            return PYTHREAD_INVALID_THREAD_ID;
        }
    }
#endif
#if defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    pthread_attr_setscope(&attrs, PTHREAD_SCOPE_SYSTEM);
#endif

    pythread_callback *callback = PyMem_RawMalloc(sizeof(pythread_callback));

    if (callback == NULL) {
      return PYTHREAD_INVALID_THREAD_ID;
    }

    callback->func = func;
    callback->arg = arg;

    status = pthread_create(&th,
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
                             &attrs,
#else
                             (pthread_attr_t*)NULL,
#endif
                             pythread_wrapper, callback);

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    pthread_attr_destroy(&attrs);
#endif

    if (status != 0) {
        PyMem_RawFree(callback);
        return PYTHREAD_INVALID_THREAD_ID;
    }

    pthread_detach(th);

#if SIZEOF_PTHREAD_T <= SIZEOF_LONG
    return (unsigned long) th;
#else
    return (unsigned long) *(unsigned long *) &th;
#endif
}

/* XXX This implementation is considered (to quote Tim Peters) "inherently
   hosed" because:
     - It does not guarantee the promise that a non-zero integer is returned.
     - The cast to unsigned long is inherently unsafe.
     - It is not clear that the 'volatile' (for AIX?) are any longer necessary.
*/
unsigned long
PyThread_get_thread_ident(void)
{
    volatile pthread_t threadid;
    if (!initialized)
        PyThread_init_thread();
    threadid = pthread_self();
    return (unsigned long) threadid;
}

#ifdef PY_HAVE_THREAD_NATIVE_ID
unsigned long
PyThread_get_thread_native_id(void)
{
    if (!initialized)
        PyThread_init_thread();
#ifdef __APPLE__
    uint64_t native_id;
    (void) pthread_threadid_np(NULL, &native_id);
#elif defined(__linux__)
    pid_t native_id;
    native_id = syscall(SYS_gettid);
#elif defined(__FreeBSD__)
    int native_id;
    native_id = pthread_getthreadid_np();
#elif defined(__OpenBSD__)
    pid_t native_id;
    native_id = getthrid();
#elif defined(_AIX)
    tid_t native_id;
    native_id = thread_self();
#elif defined(__NetBSD__)
    lwpid_t native_id;
    native_id = _lwp_self();
#endif
    return (unsigned long) native_id;
}
#endif

void _Py_NO_RETURN
PyThread_exit_thread(void)
{
    dprintf(("PyThread_exit_thread called\n"));
    if (!initialized)
        exit(0);
    pthread_exit(0);
}

#ifdef USE_SEMAPHORES

/*
 * Lock support.
 */

PyThread_type_lock
PyThread_allocate_lock(void)
{
    sem_t *lock;
    int status, error = 0;

    dprintf(("PyThread_allocate_lock called\n"));
    if (!initialized)
        PyThread_init_thread();

    lock = (sem_t *)PyMem_RawMalloc(sizeof(sem_t));

    if (lock) {
        status = sem_init(lock,0,1);
        CHECK_STATUS("sem_init");

        if (error) {
            PyMem_RawFree((void *)lock);
            lock = NULL;
        }
    }

    dprintf(("PyThread_allocate_lock() -> %p\n", (void *)lock));
    return (PyThread_type_lock)lock;
}

void
PyThread_free_lock(PyThread_type_lock lock)
{
    sem_t *thelock = (sem_t *)lock;
    int status, error = 0;

    (void) error; /* silence unused-but-set-variable warning */
    dprintf(("PyThread_free_lock(%p) called\n", lock));

    if (!thelock)
        return;

    status = sem_destroy(thelock);
    CHECK_STATUS("sem_destroy");

    PyMem_RawFree((void *)thelock);
}

/*
 * As of February 2002, Cygwin thread implementations mistakenly report error
 * codes in the return value of the sem_ calls (like the pthread_ functions).
 * Correct implementations return -1 and put the code in errno. This supports
 * either.
 */
static int
fix_status(int status)
{
    return (status == -1) ? errno : status;
}

PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,
                            int intr_flag)
{
    PyLockStatus success;
    sem_t *thelock = (sem_t *)lock;
    int status, error = 0;
    struct timespec ts;
    _PyTime_t deadline = 0;

    (void) error; /* silence unused-but-set-variable warning */
    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) called\n",
             lock, microseconds, intr_flag));

    if (microseconds > PY_TIMEOUT_MAX) {
        Py_FatalError("Timeout larger than PY_TIMEOUT_MAX");
    }

    if (microseconds > 0) {
        MICROSECONDS_TO_TIMESPEC(microseconds, ts);

        if (!intr_flag) {
            /* cannot overflow thanks to (microseconds > PY_TIMEOUT_MAX)
               check done above */
            _PyTime_t timeout = _PyTime_FromNanoseconds(microseconds * 1000);
            deadline = _PyTime_GetMonotonicClock() + timeout;
        }
    }

    while (1) {
        if (microseconds > 0) {
            status = fix_status(sem_timedwait(thelock, &ts));
        }
        else if (microseconds == 0) {
            status = fix_status(sem_trywait(thelock));
        }
        else {
            status = fix_status(sem_wait(thelock));
        }

        /* Retry if interrupted by a signal, unless the caller wants to be
           notified.  */
        if (intr_flag || status != EINTR) {
            break;
        }

        if (microseconds > 0) {
            /* wait interrupted by a signal (EINTR): recompute the timeout */
            _PyTime_t dt = deadline - _PyTime_GetMonotonicClock();
            if (dt < 0) {
                status = ETIMEDOUT;
                break;
            }
            else if (dt > 0) {
                _PyTime_t realtime_deadline = _PyTime_GetSystemClock() + dt;
                if (_PyTime_AsTimespec(realtime_deadline, &ts) < 0) {
                    /* Cannot occur thanks to (microseconds > PY_TIMEOUT_MAX)
                       check done above */
                    Py_UNREACHABLE();
                }
                /* no need to update microseconds value, the code only care
                   if (microseconds > 0 or (microseconds == 0). */
            }
            else {
                microseconds = 0;
            }
        }
    }

    /* Don't check the status if we're stopping because of an interrupt.  */
    if (!(intr_flag && status == EINTR)) {
        if (microseconds > 0) {
            if (status != ETIMEDOUT)
                CHECK_STATUS("sem_timedwait");
        }
        else if (microseconds == 0) {
            if (status != EAGAIN)
                CHECK_STATUS("sem_trywait");
        }
        else {
            CHECK_STATUS("sem_wait");
        }
    }

    if (status == 0) {
        success = PY_LOCK_ACQUIRED;
    } else if (intr_flag && status == EINTR) {
        success = PY_LOCK_INTR;
    } else {
        success = PY_LOCK_FAILURE;
    }

    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) -> %d\n",
             lock, microseconds, intr_flag, success));
    return success;
}

void
PyThread_release_lock(PyThread_type_lock lock)
{
    sem_t *thelock = (sem_t *)lock;
    int status, error = 0;

    (void) error; /* silence unused-but-set-variable warning */
    dprintf(("PyThread_release_lock(%p) called\n", lock));

    status = sem_post(thelock);
    CHECK_STATUS("sem_post");
}

#else /* USE_SEMAPHORES */

/*
 * Lock support.
 */
PyThread_type_lock
PyThread_allocate_lock(void)
{
    pthread_lock *lock;
    int status, error = 0;

    dprintf(("PyThread_allocate_lock called\n"));
    if (!initialized)
        PyThread_init_thread();

    lock = (pthread_lock *) PyMem_RawMalloc(sizeof(pthread_lock));
    if (lock) {
        memset((void *)lock, '\0', sizeof(pthread_lock));
        lock->locked = 0;

        status = pthread_mutex_init(&lock->mut, NULL);
        CHECK_STATUS_PTHREAD("pthread_mutex_init");
        /* Mark the pthread mutex underlying a Python mutex as
           pure happens-before.  We can't simply mark the
           Python-level mutex as a mutex because it can be
           acquired and released in different threads, which
           will cause errors. */
        _Py_ANNOTATE_PURE_HAPPENS_BEFORE_MUTEX(&lock->mut);

        status = _PyThread_cond_init(&lock->lock_released);
        CHECK_STATUS_PTHREAD("pthread_cond_init");

        if (error) {
            PyMem_RawFree((void *)lock);
            lock = 0;
        }
    }

    dprintf(("PyThread_allocate_lock() -> %p\n", (void *)lock));
    return (PyThread_type_lock) lock;
}

void
PyThread_free_lock(PyThread_type_lock lock)
{
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;

    (void) error; /* silence unused-but-set-variable warning */
    dprintf(("PyThread_free_lock(%p) called\n", lock));

    /* some pthread-like implementations tie the mutex to the cond
     * and must have the cond destroyed first.
     */
    status = pthread_cond_destroy( &thelock->lock_released );
    CHECK_STATUS_PTHREAD("pthread_cond_destroy");

    status = pthread_mutex_destroy( &thelock->mut );
    CHECK_STATUS_PTHREAD("pthread_mutex_destroy");

    PyMem_RawFree((void *)thelock);
}

PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,
                            int intr_flag)
{
    PyLockStatus success = PY_LOCK_FAILURE;
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;

    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) called\n",
             lock, microseconds, intr_flag));

    if (microseconds == 0) {
        status = pthread_mutex_trylock( &thelock->mut );
        if (status != EBUSY)
            CHECK_STATUS_PTHREAD("pthread_mutex_trylock[1]");
    }
    else {
        status = pthread_mutex_lock( &thelock->mut );
        CHECK_STATUS_PTHREAD("pthread_mutex_lock[1]");
    }
    if (status == 0) {
        if (thelock->locked == 0) {
            success = PY_LOCK_ACQUIRED;
        }
        else if (microseconds != 0) {
            struct timespec abs;
            if (microseconds > 0) {
                _PyThread_cond_after(microseconds, &abs);
            }
            /* continue trying until we get the lock */

            /* mut must be locked by me -- part of the condition
             * protocol */
            while (success == PY_LOCK_FAILURE) {
                if (microseconds > 0) {
                    status = pthread_cond_timedwait(
                        &thelock->lock_released,
                        &thelock->mut, &abs);
                    if (status == 1) {
                        break;
                    }
                    if (status == ETIMEDOUT)
                        break;
                    CHECK_STATUS_PTHREAD("pthread_cond_timedwait");
                }
                else {
                    status = pthread_cond_wait(
                        &thelock->lock_released,
                        &thelock->mut);
                    CHECK_STATUS_PTHREAD("pthread_cond_wait");
                }

                if (intr_flag && status == 0 && thelock->locked) {
                    /* We were woken up, but didn't get the lock.  We probably received
                     * a signal.  Return PY_LOCK_INTR to allow the caller to handle
                     * it and retry.  */
                    success = PY_LOCK_INTR;
                    break;
                }
                else if (status == 0 && !thelock->locked) {
                    success = PY_LOCK_ACQUIRED;
                }
            }
        }
        if (success == PY_LOCK_ACQUIRED) thelock->locked = 1;
        status = pthread_mutex_unlock( &thelock->mut );
        CHECK_STATUS_PTHREAD("pthread_mutex_unlock[1]");
    }

    if (error) success = PY_LOCK_FAILURE;
    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) -> %d\n",
             lock, microseconds, intr_flag, success));
    return success;
}

void
PyThread_release_lock(PyThread_type_lock lock)
{
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;

    (void) error; /* silence unused-but-set-variable warning */
    dprintf(("PyThread_release_lock(%p) called\n", lock));

    status = pthread_mutex_lock( &thelock->mut );
    CHECK_STATUS_PTHREAD("pthread_mutex_lock[3]");

    thelock->locked = 0;

    /* wake up someone (anyone, if any) waiting on the lock */
    status = pthread_cond_signal( &thelock->lock_released );
    CHECK_STATUS_PTHREAD("pthread_cond_signal");

    status = pthread_mutex_unlock( &thelock->mut );
    CHECK_STATUS_PTHREAD("pthread_mutex_unlock[3]");
}

#endif /* USE_SEMAPHORES */

int
PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
{
    return PyThread_acquire_lock_timed(lock, waitflag ? -1 : 0, /*intr_flag=*/0);
}

/* set the thread stack size.
 * Return 0 if size is valid, -1 if size is invalid,
 * -2 if setting stack size is not supported.
 */
static int
_pythread_pthread_set_stacksize(size_t size)
{
#if defined(THREAD_STACK_SIZE)
    pthread_attr_t attrs;
    size_t tss_min;
    int rc = 0;
#endif

    /* set to default */
    if (size == 0) {
        _PyInterpreterState_GET_UNSAFE()->pythread_stacksize = 0;
        return 0;
    }

#if defined(THREAD_STACK_SIZE)
#if defined(PTHREAD_STACK_MIN)
    tss_min = PTHREAD_STACK_MIN > THREAD_STACK_MIN ? PTHREAD_STACK_MIN
                                                   : THREAD_STACK_MIN;
#else
    tss_min = THREAD_STACK_MIN;
#endif
    if (size >= tss_min) {
        /* validate stack size by setting thread attribute */
        if (pthread_attr_init(&attrs) == 0) {
            rc = pthread_attr_setstacksize(&attrs, size);
            pthread_attr_destroy(&attrs);
            if (rc == 0) {
                _PyInterpreterState_GET_UNSAFE()->pythread_stacksize = size;
                return 0;
            }
        }
    }
    return -1;
#else
    return -2;
#endif
}

#define THREAD_SET_STACKSIZE(x) _pythread_pthread_set_stacksize(x)


/* Thread Local Storage (TLS) API

   This API is DEPRECATED since Python 3.7.  See PEP 539 for details.
*/

/* Issue #25658: On platforms where native TLS key is defined in a way that
   cannot be safely cast to int, PyThread_create_key returns immediately a
   failure status and other TLS functions all are no-ops.  This indicates
   clearly that the old API is not supported on platforms where it cannot be
   used reliably, and that no effort will be made to add such support.

   Note: PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT will be unnecessary after
   removing this API.
*/

int
PyThread_create_key(void)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
    pthread_key_t key;
    int fail = pthread_key_create(&key, NULL);
    if (fail)
        return -1;
    if (key > INT_MAX) {
        /* Issue #22206: handle integer overflow */
        pthread_key_delete(key);
        errno = ENOMEM;
        return -1;
    }
    return (int)key;
#else
    return -1;  /* never return valid key value. */
#endif
}

void
PyThread_delete_key(int key)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
    pthread_key_delete(key);
#endif
}

void
PyThread_delete_key_value(int key)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
    pthread_setspecific(key, NULL);
#endif
}

int
PyThread_set_key_value(int key, void *value)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
    int fail = pthread_setspecific(key, value);
    return fail ? -1 : 0;
#else
    return -1;
#endif
}

void *
PyThread_get_key_value(int key)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
    return pthread_getspecific(key);
#else
    return NULL;
#endif
}


void
PyThread_ReInitTLS(void)
{
}


/* Thread Specific Storage (TSS) API

   Platform-specific components of TSS API implementation.
*/

int
PyThread_tss_create(Py_tss_t *key)
{
    assert(key != NULL);
    /* If the key has been created, function is silently skipped. */
    if (key->_is_initialized) {
        return 0;
    }

    int fail = pthread_key_create(&(key->_key), NULL);
    if (fail) {
        return -1;
    }
    key->_is_initialized = 1;
    return 0;
}

void
PyThread_tss_delete(Py_tss_t *key)
{
    assert(key != NULL);
    /* If the key has not been created, function is silently skipped. */
    if (!key->_is_initialized) {
        return;
    }

    pthread_key_delete(key->_key);
    /* pthread has not provided the defined invalid value for the key. */
    key->_is_initialized = 0;
}

int
PyThread_tss_set(Py_tss_t *key, void *value)
{
    assert(key != NULL);
    int fail = pthread_setspecific(key->_key, value);
    return fail ? -1 : 0;
}

void *
PyThread_tss_get(Py_tss_t *key)
{
    assert(key != NULL);
    return pthread_getspecific(key->_key);
}
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