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bpo-30860: Consolidate stateful runtime globals. (#3397)

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* group the (stateful) runtime globals into various topical structs
* consolidate the topical structs under a single top-level _PyRuntimeState struct
* add a check-c-globals.py script that helps identify runtime globals

Other globals are excluded (see globals.txt and check-c-globals.py).
This commit is contained in:
Eric Snow 2017-09-07 23:51:28 -06:00 • committed by GitHub
parent bab21faded
commit 2ebc5ce42a
72 changed files with 2746 additions and 1312 deletions
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75
Python/condvar.h
View file

@ -37,27 +37,16 @@
* Condition Variable.
*/
#ifndef _CONDVAR_H_
#define _CONDVAR_H_
#ifndef _CONDVAR_IMPL_H_
#define _CONDVAR_IMPL_H_
#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
#include "internal/condvar.h"
#ifdef _POSIX_THREADS
/*
* POSIX support
*/
#define Py_HAVE_CONDVAR
#include <pthread.h>
#define PyCOND_ADD_MICROSECONDS(tv, interval) \
do { /* TODO: add overflow and truncation checks */ \
@ -74,13 +63,11 @@ do { /* TODO: add overflow and truncation checks */ \
#endif
/* The following functions return 0 on success, nonzero on error */
#define PyMUTEX_T pthread_mutex_t
#define PyMUTEX_INIT(mut) pthread_mutex_init((mut), NULL)
#define PyMUTEX_FINI(mut) pthread_mutex_destroy(mut)
#define PyMUTEX_LOCK(mut) pthread_mutex_lock(mut)
#define PyMUTEX_UNLOCK(mut) pthread_mutex_unlock(mut)
#define PyCOND_T pthread_cond_t
#define PyCOND_INIT(cond) pthread_cond_init((cond), NULL)
#define PyCOND_FINI(cond) pthread_cond_destroy(cond)
#define PyCOND_SIGNAL(cond) pthread_cond_signal(cond)
@ -116,45 +103,11 @@ PyCOND_TIMEDWAIT(PyCOND_T *cond, PyMUTEX_T *mut, long long us)
* Emulated condition variables ones that work with XP and later, plus
* example native support on VISTA and onwards.
*/
#define Py_HAVE_CONDVAR
/* include windows if it hasn't been done before */
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
/* options */
/* non-emulated condition variables are provided for those that want
* to target Windows Vista. Modify this macro to enable them.
*/
#ifndef _PY_EMULATED_WIN_CV
#define _PY_EMULATED_WIN_CV 1 /* use emulated condition variables */
#endif
/* fall back to emulation if not targeting Vista */
#if !defined NTDDI_VISTA || NTDDI_VERSION < NTDDI_VISTA
#undef _PY_EMULATED_WIN_CV
#define _PY_EMULATED_WIN_CV 1
#endif
#if _PY_EMULATED_WIN_CV
/* The mutex is a CriticalSection object and
The condition variables is emulated with the help of a semaphore.
Semaphores are available on Windows XP (2003 server) and later.
We use a Semaphore rather than an auto-reset event, because although
an auto-resent event might appear to solve the lost-wakeup bug (race
condition between releasing the outer lock and waiting) because it
maintains state even though a wait hasn't happened, there is still
a lost wakeup problem if more than one thread are interrupted in the
critical place. A semaphore solves that, because its state is counted,
not Boolean.
Because it is ok to signal a condition variable with no one
waiting, we need to keep track of the number of
waiting threads. Otherwise, the semaphore's state could rise
without bound. This also helps reduce the number of "spurious wakeups"
that would otherwise happen.
This implementation still has the problem that the threads woken
with a "signal" aren't necessarily those that are already
@ -168,8 +121,6 @@ PyCOND_TIMEDWAIT(PyCOND_T *cond, PyMUTEX_T *mut, long long us)
http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
*/
typedef CRITICAL_SECTION PyMUTEX_T;
Py_LOCAL_INLINE(int)
PyMUTEX_INIT(PyMUTEX_T *cs)
{
@ -198,15 +149,6 @@ PyMUTEX_UNLOCK(PyMUTEX_T *cs)
return 0;
}
/* The ConditionVariable object. From XP onwards it is easily emulated with
* a Semaphore
*/
typedef struct _PyCOND_T
{
HANDLE sem;
int waiting; /* to allow PyCOND_SIGNAL to be a no-op */
} PyCOND_T;
Py_LOCAL_INLINE(int)
PyCOND_INIT(PyCOND_T *cv)
@ -304,12 +246,7 @@ PyCOND_BROADCAST(PyCOND_T *cv)
return 0;
}
#else
/* Use native Win7 primitives if build target is Win7 or higher */
/* SRWLOCK is faster and better than CriticalSection */
typedef SRWLOCK PyMUTEX_T;
#else /* !_PY_EMULATED_WIN_CV */
Py_LOCAL_INLINE(int)
PyMUTEX_INIT(PyMUTEX_T *cs)
@ -339,8 +276,6 @@ PyMUTEX_UNLOCK(PyMUTEX_T *cs)
}
typedef CONDITION_VARIABLE PyCOND_T;
Py_LOCAL_INLINE(int)
PyCOND_INIT(PyCOND_T *cv)
{
@ -387,4 +322,4 @@ PyCOND_BROADCAST(PyCOND_T *cv)
#endif /* _POSIX_THREADS, NT_THREADS */
#endif /* _CONDVAR_H_ */
#endif /* _CONDVAR_IMPL_H_ */