mypyc/lib-rt/random/librt_random_api.c

#include <string.h>

#include "librt_random_api.h"

void *LibRTRandom_API[LIBRT_RANDOM_API_LEN] = {0};

int
import_librt_random(void)
{
    PyObject *mod = PyImport_ImportModule("librt.random");
    if (mod == NULL)
        return -1;
    Py_DECREF(mod);  // we import just for the side effect of making the below work.
    void **capsule = (void **)PyCapsule_Import("librt.random._C_API", 0);
    if (capsule == NULL)
        return -1;

    // Only after version validation succeeds can we safely copy the full table.
    int (*abi_version)(void) = (int (*)(void))capsule[0];
    int (*api_version)(void) = (int (*)(void))capsule[1];
    if (abi_version() != LIBRT_RANDOM_ABI_VERSION) {
        char err[128];
        snprintf(err, sizeof(err), "ABI version conflict for librt.random, expected %d, found %d",
            LIBRT_RANDOM_ABI_VERSION,
            abi_version()
        );
        PyErr_SetString(PyExc_ValueError, err);
        return -1;
    }
    if (api_version() < LIBRT_RANDOM_API_VERSION) {
        char err[128];
        snprintf(err, sizeof(err),
                 "API version conflict for librt.random, expected %d or newer, found %d (hint: upgrade librt)",
            LIBRT_RANDOM_API_VERSION,
            api_version()
        );
        PyErr_SetString(PyExc_ValueError, err);
        return -1;
    }
    // Provider API version is >= our expected version, which (by the API
    // compatibility contract) means it has at least LIBRT_RANDOM_API_LEN
    // entries, so this copy is safe.
    memcpy(LibRTRandom_API, capsule, sizeof(LibRTRandom_API));
    return 0;
}