https://github.com/python/cpython/commit/c1553bc34a537e00d6513da7df1c427df3570574
commit: c1553bc34a537e00d6513da7df1c427df3570574
branch: main
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2024-06-20T20:39:34+02:00
summary:
gh-119182: Use public PyUnicodeWriter API in union_repr() (#120797)
The public PyUnicodeWriter API enables overallocation by default and
so is more efficient.
Benchmark:
python -m pyperf timeit \
-s 't = int | float | complex | str | bytes | bytearray' \
' | memoryview | list | dict' \
'str(t)'
Result:
1.29 us +- 0.02 us -> 1.00 us +- 0.02 us: 1.29x faster
files:
M Objects/unionobject.c
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index bf5605686f8df7..49b01e0aeb5d83 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -182,15 +182,14 @@ _Py_union_type_or(PyObject* self, PyObject* other)
}
static int
-union_repr_item(_PyUnicodeWriter *writer, PyObject *p)
+union_repr_item(PyUnicodeWriter *writer, PyObject *p)
{
PyObject *qualname = NULL;
PyObject *module = NULL;
- PyObject *r = NULL;
int rc;
if (p == (PyObject *)&_PyNone_Type) {
- return _PyUnicodeWriter_WriteASCIIString(writer, "None", 4);
+ return PyUnicodeWriter_WriteUTF8(writer, "None", 4);
}
if ((rc = PyObject_HasAttrWithError(p, &_Py_ID(__origin__))) > 0 &&
@@ -200,17 +199,17 @@ union_repr_item(_PyUnicodeWriter *writer, PyObject *p)
goto use_repr;
}
if (rc < 0) {
- goto exit;
+ goto error;
}
if (PyObject_GetOptionalAttr(p, &_Py_ID(__qualname__), &qualname) < 0) {
- goto exit;
+ goto error;
}
if (qualname == NULL) {
goto use_repr;
}
if (PyObject_GetOptionalAttr(p, &_Py_ID(__module__), &module) < 0) {
- goto exit;
+ goto error;
}
if (module == NULL || module == Py_None) {
goto use_repr;
@@ -221,24 +220,25 @@ union_repr_item(_PyUnicodeWriter *writer, PyObject *p)
_PyUnicode_EqualToASCIIString(module, "builtins"))
{
// builtins don't need a module name
- r = PyObject_Str(qualname);
- goto exit;
+ rc = PyUnicodeWriter_WriteStr(writer, qualname);
+ goto done;
}
else {
- r = PyUnicode_FromFormat("%S.%S", module, qualname);
- goto exit;
+ rc = PyUnicodeWriter_Format(writer, "%S.%S", module, qualname);
+ goto done;
}
+error:
+ rc = -1;
+ goto done;
+
use_repr:
- r = PyObject_Repr(p);
-exit:
+ rc = PyUnicodeWriter_WriteRepr(writer, p);
+ goto done;
+
+done:
Py_XDECREF(qualname);
Py_XDECREF(module);
- if (r == NULL) {
- return -1;
- }
- rc = _PyUnicodeWriter_WriteStr(writer, r);
- Py_DECREF(r);
return rc;
}
@@ -248,20 +248,26 @@ union_repr(PyObject *self)
unionobject *alias = (unionobject *)self;
Py_ssize_t len = PyTuple_GET_SIZE(alias->args);
- _PyUnicodeWriter writer;
- _PyUnicodeWriter_Init(&writer);
- for (Py_ssize_t i = 0; i < len; i++) {
- if (i > 0 && _PyUnicodeWriter_WriteASCIIString(&writer, " | ", 3) < 0)
{
+ // Shortest type name "int" (3 chars) + " | " (3 chars) separator
+ Py_ssize_t estimate = (len <= PY_SSIZE_T_MAX / 6) ? len * 6 : len;
+ PyUnicodeWriter *writer = PyUnicodeWriter_Create(estimate);
+ if (writer == NULL) {
+ return NULL;
+ }
+
+ for (Py_ssize_t i = 0; i < len; i++) {
+ if (i > 0 && PyUnicodeWriter_WriteUTF8(writer, " | ", 3) < 0) {
goto error;
}
PyObject *p = PyTuple_GET_ITEM(alias->args, i);
- if (union_repr_item(&writer, p) < 0) {
+ if (union_repr_item(writer, p) < 0) {
goto error;
}
}
- return _PyUnicodeWriter_Finish(&writer);
+ return PyUnicodeWriter_Finish(writer);
+
error:
- _PyUnicodeWriter_Dealloc(&writer);
+ PyUnicodeWriter_Discard(writer);
return NULL;
}
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