mirror of https://github.com/python/cpython
73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
#ifndef Py_INTERNAL_UNIQUEID_H
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#define Py_INTERNAL_UNIQUEID_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef Py_BUILD_CORE
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# error "this header requires Py_BUILD_CORE define"
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#endif
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#ifdef Py_GIL_DISABLED
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// This contains code for allocating unique ids to objects for per-thread
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// reference counting.
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//
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// Per-thread reference counting is used along with deferred reference
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// counting to avoid scaling bottlenecks due to reference count contention.
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//
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// An id of -1 is used to indicate that an object doesn't use per-thread
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// refcounting. This value is used when the object is finalized by the GC
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// and during interpreter shutdown to allow the object to be
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// deallocated promptly when the object's refcount reaches zero.
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//
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// Each entry implicitly represents a unique id based on its offset in the
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// table. Non-allocated entries form a free-list via the 'next' pointer.
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// Allocated entries store the corresponding PyObject.
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typedef union _Py_unique_id_entry {
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// Points to the next free type id, when part of the freelist
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union _Py_unique_id_entry *next;
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// Stores the object when the id is assigned
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PyObject *obj;
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} _Py_unique_id_entry;
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struct _Py_unique_id_pool {
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PyMutex mutex;
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// combined table of object with allocated unique ids and unallocated ids.
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_Py_unique_id_entry *table;
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// Next entry to allocate inside 'table' or NULL
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_Py_unique_id_entry *freelist;
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// size of 'table'
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Py_ssize_t size;
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};
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// Assigns the next id from the pool of ids.
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extern Py_ssize_t _PyObject_AssignUniqueId(PyObject *obj);
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// Releases the allocated id back to the pool.
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extern void _PyObject_DisablePerThreadRefcounting(PyObject *obj);
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// Merges the per-thread reference counts into the corresponding objects.
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extern void _PyObject_MergePerThreadRefcounts(_PyThreadStateImpl *tstate);
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// Like _PyObject_MergePerThreadRefcounts, but also frees the per-thread
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// array of refcounts.
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extern void _PyObject_FinalizePerThreadRefcounts(_PyThreadStateImpl *tstate);
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// Frees the interpreter's pool of type ids.
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extern void _PyObject_FinalizeUniqueIdPool(PyInterpreterState *interp);
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// Increfs the object, resizing the thread-local refcount array if necessary.
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PyAPI_FUNC(void) _PyObject_ThreadIncrefSlow(PyObject *obj, Py_ssize_t unique_id);
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#endif /* Py_GIL_DISABLED */
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_INTERNAL_UNIQUEID_H */
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