#!/usr/bin/env python3
"""Guard _PyObject_Calloc's C89 declarations and original operation order."""

import re
import sys
from pathlib import Path

source = Path(sys.argv[1]).read_text()
match = re.search(
    r"\n_PyObject_Calloc\(void \*ctx, size_t nelem, size_t elsize\)\s*\{(.*?)\n\}",
    source, re.S,
)
assert match, "_PyObject_Calloc definition not found"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
assert body.split()[:4] == ["size_t", "nbytes;", "void*", "ptr;"], (
    "_PyObject_Calloc must declare nbytes and ptr without initializers at function entry"
)

# Keep multiplication after the overflow assertion, allocation after the size
# calculation, and zeroing, fallback allocation, and accounting in their order.
expected = """
    size_t nbytes;
    void* ptr;
    assert(elsize == 0 || nelem <= (size_t)PY_SSIZE_T_MAX / elsize);
    nbytes = nelem * elsize;
    ptr = pymalloc_alloc(ctx, nbytes);
    if (LIKELY(ptr != NULL)) {
        memset(ptr, 0, nbytes);
        return ptr;
    }
    ptr = PyMem_RawCalloc(nelem, elsize);
    if (ptr != NULL) {
        raw_allocated_blocks++;
    }
    return ptr;
"""
assert body.split() == expected.split(), (
    "preserve _PyObject_Calloc assertion, evaluation, zeroing, fallback, and accounting order"
)
print("obmalloc _PyObject_Calloc nbytes/ptr entry declarations and original operation order: PASS")