#!/usr/bin/env python3
"""Compile the exact PickleBuffer buffer table as C89 and check both slots."""

import re
import subprocess
import sys
import tempfile
from pathlib import Path

source_path = Path(sys.argv[1])
source = source_path.read_text()
match = re.search(r"static PyBufferProcs picklebuf_as_buffer = \{.*?\n\};", source, re.S)
assert match, "picklebuf_as_buffer initializer not found"
header = (source_path.parent.parent / "Include/cpython/object.h").read_text()
layout = re.search(r"typedef struct \{([^{}]*)\} PyBufferProcs;", header, re.S)
assert layout, "PyBufferProcs layout not found"
body = re.sub(r"/\*.*?\*/", "", layout.group(1), flags=re.S)
assert re.findall(r"\b(bf_\w+)\s*;", body) == ["bf_getbuffer", "bf_releasebuffer"]
harness = r'''
#include <assert.h>
typedef struct { int unused; } PyObject;
typedef struct { int unused; } Py_buffer;
typedef int (*getbufferproc)(PyObject *, Py_buffer *, int);
typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
static int picklebuf_getbuf(PyObject *self, Py_buffer *view, int flags)
{
    (void)self; (void)view; return flags;
}
static void picklebuf_releasebuf(PyObject *self, Py_buffer *view)
{
    (void)self; (void)view;
}
'''
harness += "typedef struct {" + body + "} PyBufferProcs;\n"
harness += match.group(0)
harness += r'''
int main(void)
{
    assert(picklebuf_as_buffer.bf_getbuffer == (getbufferproc)picklebuf_getbuf);
    assert(picklebuf_as_buffer.bf_releasebuffer == (releasebufferproc)picklebuf_releasebuf);
    return 0;
}
'''
with tempfile.TemporaryDirectory(prefix="vc6-picklebuf-buffer-") as directory:
    path = Path(directory)
    (path / "test.c").write_text(harness)
    result = subprocess.run([
        "cc", "-std=c89", "-pedantic-errors", "-Wall", "-Wextra", "-Werror",
        str(path / "test.c"), "-o", str(path / "test"),
    ])
    if result.returncode:
        sys.exit(result.returncode)
    subprocess.run([str(path / "test")], check=True)
print("picklebuf_as_buffer C89 compile and both semantic field mappings: PASS")