630 lines
17 KiB
C
630 lines
17 KiB
C
// types.GenericAlias -- used to represent e.g. list[int].
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#include "Python.h"
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#include "pycore_object.h"
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#include "structmember.h" // PyMemberDef
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typedef struct {
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PyObject_HEAD
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PyObject *origin;
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PyObject *args;
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PyObject *parameters;
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} gaobject;
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static void
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ga_dealloc(PyObject *self)
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{
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gaobject *alias = (gaobject *)self;
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_PyObject_GC_UNTRACK(self);
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Py_XDECREF(alias->origin);
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Py_XDECREF(alias->args);
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Py_XDECREF(alias->parameters);
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self->ob_type->tp_free(self);
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}
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static int
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ga_traverse(PyObject *self, visitproc visit, void *arg)
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{
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gaobject *alias = (gaobject *)self;
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Py_VISIT(alias->origin);
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Py_VISIT(alias->args);
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Py_VISIT(alias->parameters);
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return 0;
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}
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static int
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ga_repr_item(_PyUnicodeWriter *writer, PyObject *p)
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{
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_Py_IDENTIFIER(__module__);
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_Py_IDENTIFIER(__qualname__);
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_Py_IDENTIFIER(__origin__);
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_Py_IDENTIFIER(__args__);
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PyObject *qualname = NULL;
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PyObject *module = NULL;
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PyObject *r = NULL;
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PyObject *tmp;
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int err;
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if (p == Py_Ellipsis) {
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// The Ellipsis object
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r = PyUnicode_FromString("...");
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goto done;
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}
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if (_PyObject_LookupAttrId(p, &PyId___origin__, &tmp) < 0) {
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goto done;
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}
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if (tmp != NULL) {
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Py_DECREF(tmp);
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if (_PyObject_LookupAttrId(p, &PyId___args__, &tmp) < 0) {
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goto done;
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}
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if (tmp != NULL) {
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Py_DECREF(tmp);
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// It looks like a GenericAlias
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goto use_repr;
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}
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}
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if (_PyObject_LookupAttrId(p, &PyId___qualname__, &qualname) < 0) {
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goto done;
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}
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if (qualname == NULL) {
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goto use_repr;
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}
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if (_PyObject_LookupAttrId(p, &PyId___module__, &module) < 0) {
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goto done;
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}
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if (module == NULL || module == Py_None) {
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goto use_repr;
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}
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// Looks like a class
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if (PyUnicode_Check(module) &&
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_PyUnicode_EqualToASCIIString(module, "builtins"))
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{
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// builtins don't need a module name
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r = PyObject_Str(qualname);
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goto done;
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}
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else {
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r = PyUnicode_FromFormat("%S.%S", module, qualname);
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goto done;
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}
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use_repr:
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r = PyObject_Repr(p);
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done:
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Py_XDECREF(qualname);
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Py_XDECREF(module);
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if (r == NULL) {
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// error if any of the above PyObject_Repr/PyUnicode_From* fail
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err = -1;
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}
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else {
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err = _PyUnicodeWriter_WriteStr(writer, r);
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Py_DECREF(r);
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}
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return err;
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}
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static PyObject *
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ga_repr(PyObject *self)
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{
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gaobject *alias = (gaobject *)self;
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Py_ssize_t len = PyTuple_GET_SIZE(alias->args);
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_PyUnicodeWriter writer;
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_PyUnicodeWriter_Init(&writer);
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if (ga_repr_item(&writer, alias->origin) < 0) {
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goto error;
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}
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if (_PyUnicodeWriter_WriteASCIIString(&writer, "[", 1) < 0) {
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goto error;
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}
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for (Py_ssize_t i = 0; i < len; i++) {
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if (i > 0) {
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if (_PyUnicodeWriter_WriteASCIIString(&writer, ", ", 2) < 0) {
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goto error;
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}
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}
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PyObject *p = PyTuple_GET_ITEM(alias->args, i);
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if (ga_repr_item(&writer, p) < 0) {
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goto error;
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}
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}
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if (len == 0) {
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// for something like tuple[()] we should print a "()"
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if (_PyUnicodeWriter_WriteASCIIString(&writer, "()", 2) < 0) {
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goto error;
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}
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}
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if (_PyUnicodeWriter_WriteASCIIString(&writer, "]", 1) < 0) {
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goto error;
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}
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return _PyUnicodeWriter_Finish(&writer);
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error:
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_PyUnicodeWriter_Dealloc(&writer);
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return NULL;
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}
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// isinstance(obj, TypeVar) without importing typing.py.
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// Returns -1 for errors.
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static int
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is_typevar(PyObject *obj)
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{
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PyTypeObject *type = Py_TYPE(obj);
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if (strcmp(type->tp_name, "TypeVar") != 0) {
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return 0;
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}
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PyObject *module = PyObject_GetAttrString((PyObject *)type, "__module__");
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if (module == NULL) {
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return -1;
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}
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int res = PyUnicode_Check(module)
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&& _PyUnicode_EqualToASCIIString(module, "typing");
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Py_DECREF(module);
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return res;
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}
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// Index of item in self[:len], or -1 if not found (self is a tuple)
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static Py_ssize_t
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tuple_index(PyObject *self, Py_ssize_t len, PyObject *item)
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{
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for (Py_ssize_t i = 0; i < len; i++) {
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if (PyTuple_GET_ITEM(self, i) == item) {
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return i;
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}
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}
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return -1;
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}
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static int
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tuple_add(PyObject *self, Py_ssize_t len, PyObject *item)
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{
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if (tuple_index(self, len, item) < 0) {
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Py_INCREF(item);
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PyTuple_SET_ITEM(self, len, item);
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return 1;
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}
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return 0;
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}
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static PyObject *
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make_parameters(PyObject *args)
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{
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Py_ssize_t nargs = PyTuple_GET_SIZE(args);
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Py_ssize_t len = nargs;
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PyObject *parameters = PyTuple_New(len);
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if (parameters == NULL)
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return NULL;
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Py_ssize_t iparam = 0;
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for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
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PyObject *t = PyTuple_GET_ITEM(args, iarg);
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int typevar = is_typevar(t);
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if (typevar < 0) {
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Py_DECREF(parameters);
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return NULL;
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}
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if (typevar) {
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iparam += tuple_add(parameters, iparam, t);
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}
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else {
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_Py_IDENTIFIER(__parameters__);
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PyObject *subparams;
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if (_PyObject_LookupAttrId(t, &PyId___parameters__, &subparams) < 0) {
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Py_DECREF(parameters);
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return NULL;
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}
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if (subparams && PyTuple_Check(subparams)) {
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Py_ssize_t len2 = PyTuple_GET_SIZE(subparams);
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Py_ssize_t needed = len2 - 1 - (iarg - iparam);
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if (needed > 0) {
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len += needed;
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if (_PyTuple_Resize(¶meters, len) < 0) {
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Py_DECREF(subparams);
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Py_DECREF(parameters);
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return NULL;
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}
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}
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for (Py_ssize_t j = 0; j < len2; j++) {
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PyObject *t2 = PyTuple_GET_ITEM(subparams, j);
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iparam += tuple_add(parameters, iparam, t2);
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}
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}
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Py_XDECREF(subparams);
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}
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}
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if (iparam < len) {
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if (_PyTuple_Resize(¶meters, iparam) < 0) {
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Py_XDECREF(parameters);
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return NULL;
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}
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}
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return parameters;
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}
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/* If obj is a generic alias, substitute type variables params
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with substitutions argitems. For example, if obj is list[T],
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params is (T, S), and argitems is (str, int), return list[str].
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If obj doesn't have a __parameters__ attribute or that's not
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a non-empty tuple, return a new reference to obj. */
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static PyObject *
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subs_tvars(PyObject *obj, PyObject *params, PyObject **argitems)
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{
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_Py_IDENTIFIER(__parameters__);
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PyObject *subparams;
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if (_PyObject_LookupAttrId(obj, &PyId___parameters__, &subparams) < 0) {
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return NULL;
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}
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if (subparams && PyTuple_Check(subparams) && PyTuple_GET_SIZE(subparams)) {
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Py_ssize_t nparams = PyTuple_GET_SIZE(params);
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Py_ssize_t nsubargs = PyTuple_GET_SIZE(subparams);
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PyObject *subargs = PyTuple_New(nsubargs);
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if (subargs == NULL) {
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Py_DECREF(subparams);
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return NULL;
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}
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for (Py_ssize_t i = 0; i < nsubargs; ++i) {
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PyObject *arg = PyTuple_GET_ITEM(subparams, i);
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Py_ssize_t iparam = tuple_index(params, nparams, arg);
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if (iparam >= 0) {
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arg = argitems[iparam];
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}
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Py_INCREF(arg);
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PyTuple_SET_ITEM(subargs, i, arg);
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}
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obj = PyObject_GetItem(obj, subargs);
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Py_DECREF(subargs);
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}
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else {
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Py_INCREF(obj);
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}
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Py_XDECREF(subparams);
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return obj;
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}
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static PyObject *
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ga_getitem(PyObject *self, PyObject *item)
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{
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gaobject *alias = (gaobject *)self;
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// do a lookup for __parameters__ so it gets populated (if not already)
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if (alias->parameters == NULL) {
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alias->parameters = make_parameters(alias->args);
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if (alias->parameters == NULL) {
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return NULL;
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}
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}
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Py_ssize_t nparams = PyTuple_GET_SIZE(alias->parameters);
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if (nparams == 0) {
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return PyErr_Format(PyExc_TypeError,
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"There are no type variables left in %R",
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self);
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}
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int is_tuple = PyTuple_Check(item);
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Py_ssize_t nitems = is_tuple ? PyTuple_GET_SIZE(item) : 1;
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PyObject **argitems = is_tuple ? &PyTuple_GET_ITEM(item, 0) : &item;
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if (nitems != nparams) {
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return PyErr_Format(PyExc_TypeError,
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"Too %s arguments for %R",
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nitems > nparams ? "many" : "few",
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self);
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}
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/* Replace all type variables (specified by alias->parameters)
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with corresponding values specified by argitems.
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t = list[T]; t[int] -> newargs = [int]
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t = dict[str, T]; t[int] -> newargs = [str, int]
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t = dict[T, list[S]]; t[str, int] -> newargs = [str, list[int]]
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*/
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Py_ssize_t nargs = PyTuple_GET_SIZE(alias->args);
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PyObject *newargs = PyTuple_New(nargs);
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if (newargs == NULL) {
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return NULL;
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}
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for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
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PyObject *arg = PyTuple_GET_ITEM(alias->args, iarg);
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int typevar = is_typevar(arg);
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if (typevar < 0) {
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Py_DECREF(newargs);
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return NULL;
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}
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if (typevar) {
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Py_ssize_t iparam = tuple_index(alias->parameters, nparams, arg);
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assert(iparam >= 0);
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arg = argitems[iparam];
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Py_INCREF(arg);
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}
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else {
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arg = subs_tvars(arg, alias->parameters, argitems);
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if (arg == NULL) {
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Py_DECREF(newargs);
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return NULL;
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}
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}
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PyTuple_SET_ITEM(newargs, iarg, arg);
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}
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PyObject *res = Py_GenericAlias(alias->origin, newargs);
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Py_DECREF(newargs);
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return res;
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}
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static PyMappingMethods ga_as_mapping = {
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.mp_subscript = ga_getitem,
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};
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static Py_hash_t
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ga_hash(PyObject *self)
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{
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gaobject *alias = (gaobject *)self;
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// TODO: Hash in the hash for the origin
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Py_hash_t h0 = PyObject_Hash(alias->origin);
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if (h0 == -1) {
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return -1;
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}
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Py_hash_t h1 = PyObject_Hash(alias->args);
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if (h1 == -1) {
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return -1;
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}
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return h0 ^ h1;
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}
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static PyObject *
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ga_call(PyObject *self, PyObject *args, PyObject *kwds)
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{
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gaobject *alias = (gaobject *)self;
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PyObject *obj = PyObject_Call(alias->origin, args, kwds);
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if (obj != NULL) {
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if (PyObject_SetAttrString(obj, "__orig_class__", self) < 0) {
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if (!PyErr_ExceptionMatches(PyExc_AttributeError) &&
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!PyErr_ExceptionMatches(PyExc_TypeError))
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{
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Py_DECREF(obj);
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return NULL;
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}
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PyErr_Clear();
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}
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}
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return obj;
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}
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static const char* const attr_exceptions[] = {
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"__origin__",
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"__args__",
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"__parameters__",
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"__mro_entries__",
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"__reduce_ex__", // needed so we don't look up object.__reduce_ex__
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"__reduce__",
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NULL,
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};
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static PyObject *
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ga_getattro(PyObject *self, PyObject *name)
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{
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gaobject *alias = (gaobject *)self;
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if (PyUnicode_Check(name)) {
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for (const char * const *p = attr_exceptions; ; p++) {
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if (*p == NULL) {
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return PyObject_GetAttr(alias->origin, name);
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}
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if (_PyUnicode_EqualToASCIIString(name, *p)) {
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break;
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}
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}
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}
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return PyObject_GenericGetAttr(self, name);
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}
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static PyObject *
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ga_richcompare(PyObject *a, PyObject *b, int op)
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{
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if (!Py_IS_TYPE(a, &Py_GenericAliasType) ||
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!Py_IS_TYPE(b, &Py_GenericAliasType) ||
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(op != Py_EQ && op != Py_NE))
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{
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Py_RETURN_NOTIMPLEMENTED;
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}
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if (op == Py_NE) {
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PyObject *eq = ga_richcompare(a, b, Py_EQ);
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if (eq == NULL)
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return NULL;
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Py_DECREF(eq);
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if (eq == Py_True) {
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Py_RETURN_FALSE;
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}
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else {
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Py_RETURN_TRUE;
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}
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}
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gaobject *aa = (gaobject *)a;
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gaobject *bb = (gaobject *)b;
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int eq = PyObject_RichCompareBool(aa->origin, bb->origin, Py_EQ);
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if (eq < 0) {
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return NULL;
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}
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if (!eq) {
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Py_RETURN_FALSE;
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}
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return PyObject_RichCompare(aa->args, bb->args, Py_EQ);
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}
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static PyObject *
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ga_mro_entries(PyObject *self, PyObject *args)
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{
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gaobject *alias = (gaobject *)self;
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return PyTuple_Pack(1, alias->origin);
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}
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|
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static PyObject *
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ga_instancecheck(PyObject *self, PyObject *Py_UNUSED(ignored))
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{
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PyErr_SetString(PyExc_TypeError,
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"isinstance() argument 2 cannot be a parameterized generic");
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return NULL;
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}
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|
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static PyObject *
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ga_subclasscheck(PyObject *self, PyObject *Py_UNUSED(ignored))
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{
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PyErr_SetString(PyExc_TypeError,
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"issubclass() argument 2 cannot be a parameterized generic");
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return NULL;
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}
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static PyObject *
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ga_reduce(PyObject *self, PyObject *Py_UNUSED(ignored))
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{
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gaobject *alias = (gaobject *)self;
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return Py_BuildValue("O(OO)", Py_TYPE(alias),
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alias->origin, alias->args);
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}
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|
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static PyObject *
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ga_dir(PyObject *self, PyObject *Py_UNUSED(ignored))
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{
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gaobject *alias = (gaobject *)self;
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PyObject *dir = PyObject_Dir(alias->origin);
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if (dir == NULL) {
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return NULL;
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}
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PyObject *dir_entry = NULL;
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for (const char * const *p = attr_exceptions; ; p++) {
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if (*p == NULL) {
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break;
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}
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else {
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dir_entry = PyUnicode_FromString(*p);
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if (dir_entry == NULL) {
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goto error;
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}
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int contains = PySequence_Contains(dir, dir_entry);
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if (contains < 0) {
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goto error;
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}
|
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if (contains == 0 && PyList_Append(dir, dir_entry) < 0) {
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goto error;
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}
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Py_CLEAR(dir_entry);
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}
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}
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return dir;
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|
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error:
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Py_DECREF(dir);
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Py_XDECREF(dir_entry);
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return NULL;
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}
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|
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static PyMethodDef ga_methods[] = {
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{"__mro_entries__", ga_mro_entries, METH_O},
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|
{"__instancecheck__", ga_instancecheck, METH_O},
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|
{"__subclasscheck__", ga_subclasscheck, METH_O},
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|
{"__reduce__", ga_reduce, METH_NOARGS},
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{"__dir__", ga_dir, METH_NOARGS},
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|
{0}
|
|
};
|
|
|
|
static PyMemberDef ga_members[] = {
|
|
{"__origin__", T_OBJECT, offsetof(gaobject, origin), READONLY},
|
|
{"__args__", T_OBJECT, offsetof(gaobject, args), READONLY},
|
|
{0}
|
|
};
|
|
|
|
static PyObject *
|
|
ga_parameters(PyObject *self, void *unused)
|
|
{
|
|
gaobject *alias = (gaobject *)self;
|
|
if (alias->parameters == NULL) {
|
|
alias->parameters = make_parameters(alias->args);
|
|
if (alias->parameters == NULL) {
|
|
return NULL;
|
|
}
|
|
}
|
|
Py_INCREF(alias->parameters);
|
|
return alias->parameters;
|
|
}
|
|
|
|
static PyGetSetDef ga_properties[] = {
|
|
{"__parameters__", ga_parameters, (setter)NULL, "Type variables in the GenericAlias.", NULL},
|
|
{0}
|
|
};
|
|
|
|
static PyObject *
|
|
ga_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
|
|
{
|
|
if (!_PyArg_NoKwnames("GenericAlias", kwds)) {
|
|
return NULL;
|
|
}
|
|
if (!_PyArg_CheckPositional("GenericAlias", PyTuple_GET_SIZE(args), 2, 2)) {
|
|
return NULL;
|
|
}
|
|
PyObject *origin = PyTuple_GET_ITEM(args, 0);
|
|
PyObject *arguments = PyTuple_GET_ITEM(args, 1);
|
|
return Py_GenericAlias(origin, arguments);
|
|
}
|
|
|
|
// TODO:
|
|
// - argument clinic?
|
|
// - __doc__?
|
|
// - cache?
|
|
PyTypeObject Py_GenericAliasType = {
|
|
PyVarObject_HEAD_INIT(&PyType_Type, 0)
|
|
.tp_name = "types.GenericAlias",
|
|
.tp_doc = "Represent a PEP 585 generic type\n"
|
|
"\n"
|
|
"E.g. for t = list[int], t.origin is list and t.args is (int,).",
|
|
.tp_basicsize = sizeof(gaobject),
|
|
.tp_dealloc = ga_dealloc,
|
|
.tp_repr = ga_repr,
|
|
.tp_as_mapping = &ga_as_mapping,
|
|
.tp_hash = ga_hash,
|
|
.tp_call = ga_call,
|
|
.tp_getattro = ga_getattro,
|
|
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
|
|
.tp_traverse = ga_traverse,
|
|
.tp_richcompare = ga_richcompare,
|
|
.tp_methods = ga_methods,
|
|
.tp_members = ga_members,
|
|
.tp_alloc = PyType_GenericAlloc,
|
|
.tp_new = ga_new,
|
|
.tp_free = PyObject_GC_Del,
|
|
.tp_getset = ga_properties,
|
|
};
|
|
|
|
PyObject *
|
|
Py_GenericAlias(PyObject *origin, PyObject *args)
|
|
{
|
|
if (!PyTuple_Check(args)) {
|
|
args = PyTuple_Pack(1, args);
|
|
if (args == NULL) {
|
|
return NULL;
|
|
}
|
|
}
|
|
else {
|
|
Py_INCREF(args);
|
|
}
|
|
|
|
gaobject *alias = PyObject_GC_New(gaobject, &Py_GenericAliasType);
|
|
if (alias == NULL) {
|
|
Py_DECREF(args);
|
|
return NULL;
|
|
}
|
|
|
|
Py_INCREF(origin);
|
|
alias->origin = origin;
|
|
alias->args = args;
|
|
alias->parameters = NULL;
|
|
_PyObject_GC_TRACK(alias);
|
|
return (PyObject *)alias;
|
|
}
|