#!/usr/bin/env python3
"""Focused Visual C++ 6.0 C89 regression checks for object.c."""

import re
import sys
from pathlib import Path

source = Path(sys.argv[1]).read_text()


def body(name):
    found = re.search(re.escape(name) + r"\s*\([^;]*\)\s*\{(?P<body>.*?)\n\}", source, re.S)
    assert found, name + " definition not found"
    return found.group("body")


def check(name, tokens, message):
    text = body(name)
    positions = [text.find(token) for token in tokens]
    assert all(position >= 0 for position in positions) and positions == sorted(positions), message
    return text


text = check("PyObject_CallFinalizerFromDealloc", (
    "Py_ssize_t refcnt;",
    "if (Py_REFCNT(self) != 0)",
    "refcnt = Py_REFCNT(self);",
    "_Py_NewReference(self);",
    "Py_SET_REFCNT(self, refcnt);",
), "PyObject_CallFinalizerFromDealloc must hoist refcnt while preserving resurrection order")
assert "Py_ssize_t refcnt =" not in text
print("object PyObject_CallFinalizerFromDealloc C89 local and refcount order: PASS")

text = check("_PyObject_Dump", (
    "PyTypeObject *type;",
    "PyGILState_STATE gil;",
    "PyObject *error_type, *error_value, *error_traceback;",
    "if (_PyObject_IsFreed(op))",
    "type = Py_TYPE(op);",
    "gil = PyGILState_Ensure();",
    "PyErr_Fetch(&error_type, &error_value, &error_traceback);",
), "_PyObject_Dump must hoist locals without changing diagnostics or exception preservation")
assert "PyTypeObject *type =" not in text and "PyGILState_STATE gil =" not in text
print("object _PyObject_Dump C89 locals and exception preservation: PASS")

text = check("PyObject_Repr", (
    "PyObject *res;",
    "PyThreadState *tstate;",
    "if (PyErr_CheckSignals())",
    "tstate = _PyThreadState_GET();",
), "PyObject_Repr must hoist tstate while preserving signal-check order")
assert "PyThreadState *tstate =" not in text
print("object PyObject_Repr C89 local and signal-check order: PASS")

text = body("_PyObject_DictPointer")
expected = '''
    Py_ssize_t dictoffset;
    PyTypeObject *tp = Py_TYPE(obj);

    if (tp->tp_flags & Py_TPFLAGS_MANAGED_DICT) {
        return _PyObject_ManagedDictPointer(obj);
    }
    dictoffset = tp->tp_dictoffset;
    if (dictoffset == 0)
        return NULL;
    if (dictoffset < 0) {
        Py_ssize_t tsize = Py_SIZE(obj);
        size_t size;
        if (tsize < 0) {
            tsize = -tsize;
        }
        size = _PyObject_VAR_SIZE(tp, tsize);
        assert(size <= (size_t)PY_SSIZE_T_MAX);
        dictoffset += (Py_ssize_t)size;

        _PyObject_ASSERT(obj, dictoffset > 0);
        _PyObject_ASSERT(obj, dictoffset % SIZEOF_VOID_P == 0);
    }
    return (PyObject **) ((char *)obj + dictoffset);
'''
assert text.split() == expected.split(), (
    "_PyObject_DictPointer must hoist only size to the block's opening declarations "
    "and preserve the size expression and statement order"
)
print("object _PyObject_DictPointer C89 size declaration and offset calculation order: PASS")