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bpo-40521: Make bytes singletons per interpreter (GH-21074)

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Each interpreter now has its own empty bytes string and single byte
character singletons.

Replace STRINGLIB_EMPTY macro with STRINGLIB_GET_EMPTY() macro.
This commit is contained in:
Victor Stinner 2020-06-23 15:54:35 +02:00 • committed by GitHub
parent 32f2eda859
commit c41eed1a87
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GPG key ID: 4AEE18F83AFDEB23
13 changed files with 96 additions and 53 deletions
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82
Objects/bytesobject.c
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@ -18,9 +18,6 @@ class bytes "PyBytesObject *" "&PyBytes_Type"
#include "clinic/bytesobject.c.h"
static PyBytesObject *characters[UCHAR_MAX + 1];
static PyBytesObject *nullstring;
_Py_IDENTIFIER(__bytes__);
/* PyBytesObject_SIZE gives the basic size of a string; any memory allocation
@ -35,6 +32,15 @@ _Py_IDENTIFIER(__bytes__);
Py_LOCAL_INLINE(Py_ssize_t) _PyBytesWriter_GetSize(_PyBytesWriter *writer,
char *str);
static struct _Py_bytes_state*
get_bytes_state(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
return &interp->bytes;
}
/*
For PyBytes_FromString(), the parameter `str' points to a null-terminated
string containing exactly `size' bytes.
@ -63,9 +69,13 @@ _PyBytes_FromSize(Py_ssize_t size, int use_calloc)
PyBytesObject *op;
assert(size >= 0);
if (size == 0 && (op = nullstring) != NULL) {
Py_INCREF(op);
return (PyObject *)op;
if (size == 0) {
struct _Py_bytes_state *state = get_bytes_state();
op = state->empty_string;
if (op != NULL) {
Py_INCREF(op);
return (PyObject *)op;
}
}
if ((size_t)size > (size_t)PY_SSIZE_T_MAX - PyBytesObject_SIZE) {
@ -88,8 +98,9 @@ _PyBytes_FromSize(Py_ssize_t size, int use_calloc)
op->ob_sval[size] = '\0';
/* empty byte string singleton */
if (size == 0) {
nullstring = op;
struct _Py_bytes_state *state = get_bytes_state();
Py_INCREF(op);
state->empty_string = op;
}
return (PyObject *) op;
}
@ -103,11 +114,13 @@ PyBytes_FromStringAndSize(const char *str, Py_ssize_t size)
"Negative size passed to PyBytes_FromStringAndSize");
return NULL;
}
if (size == 1 && str != NULL &&
(op = characters[*str & UCHAR_MAX]) != NULL)
{
Py_INCREF(op);
return (PyObject *)op;
if (size == 1 && str != NULL) {
struct _Py_bytes_state *state = get_bytes_state();
op = state->characters[*str & UCHAR_MAX];
if (op != NULL) {
Py_INCREF(op);
return (PyObject *)op;
}
}
op = (PyBytesObject *)_PyBytes_FromSize(size, 0);
@ -119,8 +132,9 @@ PyBytes_FromStringAndSize(const char *str, Py_ssize_t size)
memcpy(op->ob_sval, str, size);
/* share short strings */
if (size == 1) {
characters[*str & UCHAR_MAX] = op;
struct _Py_bytes_state *state = get_bytes_state();
Py_INCREF(op);
state->characters[*str & UCHAR_MAX] = op;
}
return (PyObject *) op;
}
@ -138,13 +152,21 @@ PyBytes_FromString(const char *str)
"byte string is too long");
return NULL;
}
if (size == 0 && (op = nullstring) != NULL) {
Py_INCREF(op);
return (PyObject *)op;
struct _Py_bytes_state *state = get_bytes_state();
if (size == 0) {
op = state->empty_string;
if (op != NULL) {
Py_INCREF(op);
return (PyObject *)op;
}
}
if (size == 1 && (op = characters[*str & UCHAR_MAX]) != NULL) {
Py_INCREF(op);
return (PyObject *)op;
else if (size == 1) {
op = state->characters[*str & UCHAR_MAX];
if (op != NULL) {
Py_INCREF(op);
return (PyObject *)op;
}
}
/* Inline PyObject_NewVar */
@ -157,11 +179,12 @@ PyBytes_FromString(const char *str)
memcpy(op->ob_sval, str, size+1);
/* share short strings */
if (size == 0) {
nullstring = op;
Py_INCREF(op);
} else if (size == 1) {
characters[*str & UCHAR_MAX] = op;
state->empty_string = op;
}
else if (size == 1) {
Py_INCREF(op);
state->characters[*str & UCHAR_MAX] = op;
}
return (PyObject *) op;
}
@ -1249,6 +1272,8 @@ PyBytes_AsStringAndSize(PyObject *obj,
/* -------------------------------------------------------------------- */
/* Methods */
#define STRINGLIB_GET_EMPTY() get_bytes_state()->empty_string
#include "stringlib/stringdefs.h"
#include "stringlib/fastsearch.h"
@ -1261,6 +1286,8 @@ PyBytes_AsStringAndSize(PyObject *obj,
#include "stringlib/transmogrify.h"
#undef STRINGLIB_GET_EMPTY
PyObject *
PyBytes_Repr(PyObject *obj, int smartquotes)
{
@ -3058,12 +3085,13 @@ error:
}
void
_PyBytes_Fini(void)
_PyBytes_Fini(PyThreadState *tstate)
{
int i;
for (i = 0; i < UCHAR_MAX + 1; i++)
Py_CLEAR(characters[i]);
Py_CLEAR(nullstring);
struct _Py_bytes_state* state = &tstate->interp->bytes;
for (int i = 0; i < UCHAR_MAX + 1; i++) {
Py_CLEAR(state->characters[i]);
}
Py_CLEAR(state->empty_string);
}
/*********************** Bytes Iterator ****************************/