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99400930ac
* Add definitions for "context", "current context", and "context
management protocol".
* Update related definitions to be consistent with the new
definitions.
* Restructure the documentation for the `contextvars.Context` class
to prepare for adding context manager support, and for consistency
with the definitions.
* Use `testcode` and `testoutput` to test the `Context.run` example.
* Expand the documentation for the `Py_CONTEXT_EVENT_ENTER` and
`Py_CONTEXT_EVENT_EXIT` events to clarify and to prepare for
planned changes.
116 lines
3.3 KiB
C
116 lines
3.3 KiB
C
#ifndef Py_LIMITED_API
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#ifndef Py_CONTEXT_H
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#define Py_CONTEXT_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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PyAPI_DATA(PyTypeObject) PyContext_Type;
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typedef struct _pycontextobject PyContext;
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PyAPI_DATA(PyTypeObject) PyContextVar_Type;
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typedef struct _pycontextvarobject PyContextVar;
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PyAPI_DATA(PyTypeObject) PyContextToken_Type;
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typedef struct _pycontexttokenobject PyContextToken;
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#define PyContext_CheckExact(o) Py_IS_TYPE((o), &PyContext_Type)
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#define PyContextVar_CheckExact(o) Py_IS_TYPE((o), &PyContextVar_Type)
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#define PyContextToken_CheckExact(o) Py_IS_TYPE((o), &PyContextToken_Type)
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PyAPI_FUNC(PyObject *) PyContext_New(void);
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PyAPI_FUNC(PyObject *) PyContext_Copy(PyObject *);
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PyAPI_FUNC(PyObject *) PyContext_CopyCurrent(void);
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PyAPI_FUNC(int) PyContext_Enter(PyObject *);
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PyAPI_FUNC(int) PyContext_Exit(PyObject *);
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typedef enum {
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/*
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* A context has been entered, causing the "current context" to switch to
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* it. The object passed to the watch callback is the now-current
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* contextvars.Context object. Each enter event will eventually have a
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* corresponding exit event for the same context object after any
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* subsequently entered contexts have themselves been exited.
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*/
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Py_CONTEXT_EVENT_ENTER,
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/*
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* A context is about to be exited, which will cause the "current context"
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* to switch back to what it was before the context was entered. The
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* object passed to the watch callback is the still-current
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* contextvars.Context object.
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*/
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Py_CONTEXT_EVENT_EXIT,
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} PyContextEvent;
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/*
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* Context object watcher callback function. The object passed to the callback
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* is event-specific; see PyContextEvent for details.
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*
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* if the callback returns with an exception set, it must return -1. Otherwise
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* it should return 0
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*/
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typedef int (*PyContext_WatchCallback)(PyContextEvent, PyContext *);
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/*
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* Register a per-interpreter callback that will be invoked for context object
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* enter/exit events.
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*
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* Returns a handle that may be passed to PyContext_ClearWatcher on success,
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* or -1 and sets and error if no more handles are available.
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*/
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PyAPI_FUNC(int) PyContext_AddWatcher(PyContext_WatchCallback callback);
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/*
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* Clear the watcher associated with the watcher_id handle.
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*
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* Returns 0 on success or -1 if no watcher exists for the provided id.
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*/
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PyAPI_FUNC(int) PyContext_ClearWatcher(int watcher_id);
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/* Create a new context variable.
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default_value can be NULL.
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*/
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PyAPI_FUNC(PyObject *) PyContextVar_New(
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const char *name, PyObject *default_value);
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/* Get a value for the variable.
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Returns -1 if an error occurred during lookup.
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Returns 0 if value either was or was not found.
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If value was found, *value will point to it.
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If not, it will point to:
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- default_value, if not NULL;
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- the default value of "var", if not NULL;
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- NULL.
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'*value' will be a new ref, if not NULL.
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*/
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PyAPI_FUNC(int) PyContextVar_Get(
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PyObject *var, PyObject *default_value, PyObject **value);
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/* Set a new value for the variable.
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Returns NULL if an error occurs.
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*/
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PyAPI_FUNC(PyObject *) PyContextVar_Set(PyObject *var, PyObject *value);
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/* Reset a variable to its previous value.
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Returns 0 on success, -1 on error.
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*/
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PyAPI_FUNC(int) PyContextVar_Reset(PyObject *var, PyObject *token);
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_CONTEXT_H */
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#endif /* !Py_LIMITED_API */
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