#!/usr/bin/env python3
"""Guard insert_to_freepool's C89 locals and complete operation order."""

import re
import sys
from pathlib import Path

source = Path(sys.argv[1]).read_text()
match = re.search(
    r"\ninsert_to_freepool\(poolp pool\)\s*\{(.*?)\n\}",
    source, re.S,
)
assert match, "insert_to_freepool definition not found"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
declarations = """
    poolp next;
    poolp prev;
    struct arena_object *ao;
    uint nf;
    struct arena_object* lastnf;
    struct arena_object* p;
"""
assert body.split()[:len(declarations.split())] == declarations.split(), (
    "insert_to_freepool must declare all six locals without initializers at function entry"
)

# Assignments stay at the original evaluation points, including p inside its
# branch. Preserve every assertion, branch, return, and pointer update, as well
# as the radix-tree conditional, throughout all four arena-management cases.
expected = declarations + """
    next = pool->nextpool;
    prev = pool->prevpool;
    next->prevpool = prev;
    prev->nextpool = next;
    ao = &arenas[pool->arenaindex];
    pool->nextpool = ao->freepools;
    ao->freepools = pool;
    nf = ao->nfreepools;
    lastnf = nfp2lasta[nf];
    assert((nf == 0 && lastnf == NULL) ||
           (nf > 0 &&
            lastnf != NULL &&
            lastnf->nfreepools == nf &&
            (lastnf->nextarena == NULL ||
             nf < lastnf->nextarena->nfreepools)));
    if (lastnf == ao) {
        p = ao->prevarena;
        nfp2lasta[nf] = (p != NULL && p->nfreepools == nf) ? p : NULL;
    }
    ao->nfreepools = ++nf;
    if (nf == ao->ntotalpools && ao->nextarena != NULL) {
        assert(ao->prevarena == NULL ||
               ao->prevarena->address != 0);
        assert(ao ->nextarena == NULL ||
               ao->nextarena->address != 0);
        if (ao->prevarena == NULL) {
            usable_arenas = ao->nextarena;
            assert(usable_arenas == NULL ||
                   usable_arenas->address != 0);
        }
        else {
            assert(ao->prevarena->nextarena == ao);
            ao->prevarena->nextarena =
                ao->nextarena;
        }
        if (ao->nextarena != NULL) {
            assert(ao->nextarena->prevarena == ao);
            ao->nextarena->prevarena =
                ao->prevarena;
        }
        ao->nextarena = unused_arena_objects;
        unused_arena_objects = ao;
#if WITH_PYMALLOC_RADIX_TREE
        arena_map_mark_used(ao->address, 0);
#endif
        _PyObject_Arena.free(_PyObject_Arena.ctx,
                             (void *)ao->address, ARENA_SIZE);
        ao->address = 0;
        --narenas_currently_allocated;
        return;
    }
    if (nf == 1) {
        ao->nextarena = usable_arenas;
        ao->prevarena = NULL;
        if (usable_arenas)
            usable_arenas->prevarena = ao;
        usable_arenas = ao;
        assert(usable_arenas->address != 0);
        if (nfp2lasta[1] == NULL) {
            nfp2lasta[1] = ao;
        }
        return;
    }
    if (nfp2lasta[nf] == NULL) {
        nfp2lasta[nf] = ao;
    }
    if (ao == lastnf) {
        return;
    }
    assert(ao->nextarena != NULL);
    if (ao->prevarena != NULL) {
        assert(ao->prevarena->nextarena == ao);
        ao->prevarena->nextarena = ao->nextarena;
    }
    else {
        assert(usable_arenas == ao);
        usable_arenas = ao->nextarena;
    }
    ao->nextarena->prevarena = ao->prevarena;
    ao->prevarena = lastnf;
    ao->nextarena = lastnf->nextarena;
    if (ao->nextarena != NULL) {
        ao->nextarena->prevarena = ao;
    }
    lastnf->nextarena = ao;
    assert(ao->nextarena == NULL || nf <= ao->nextarena->nfreepools);
    assert(ao->prevarena == NULL || nf > ao->prevarena->nfreepools);
    assert(ao->nextarena == NULL || ao->nextarena->prevarena == ao);
    assert((usable_arenas == ao && ao->prevarena == NULL)
           || ao->prevarena->nextarena == ao);
"""
assert body.split() == expected.split(), (
    "preserve insert_to_freepool evaluation, assertion, control-flow, and pointer-update order"
)
print("obmalloc insert_to_freepool entry declarations and original operation order: PASS")