nix-super/src/libutil/c/nix_api_util.cc

#include "nix_api_util.h"
#include "config.hh"
#include "error.hh"
#include "nix_api_util_internal.h"
#include "util.hh"

#include <cxxabi.h>
#include <typeinfo>

nix_c_context * nix_c_context_create()
{
    return new nix_c_context();
}

void nix_c_context_free(nix_c_context * context)
{
    delete context;
}

nix_err nix_context_error(nix_c_context * context)
{
    if (context == nullptr) {
        throw;
    }
    try {
        throw;
    } catch (nix::Error & e) {
        /* Storing this exception is annoying, take what we need here */
        context->last_err = e.what();
        context->info = e.info();
        int status;
        const char * demangled = abi::__cxa_demangle(typeid(e).name(), 0, 0, &status);
        if (demangled) {
            context->name = demangled;
            // todo: free(demangled);
        } else {
            context->name = typeid(e).name();
        }
        context->last_err_code = NIX_ERR_NIX_ERROR;
        return context->last_err_code;
    } catch (const std::exception & e) {
        context->last_err = e.what();
        context->last_err_code = NIX_ERR_UNKNOWN;
        return context->last_err_code;
    }
    // unreachable
}

nix_err nix_set_err_msg(nix_c_context * context, nix_err err, const char * msg)
{
    if (context == nullptr) {
        // todo last_err_code
        throw nix::Error("Nix C api error: %s", msg);
    }
    context->last_err_code = err;
    context->last_err = msg;
    return err;
}

const char * nix_version_get()
{
    return PACKAGE_VERSION;
}

// Implementations
nix_err nix_setting_get(nix_c_context * context, const char * key, char * value, int n)
{
    if (context)
        context->last_err_code = NIX_OK;
    try {
        std::map<std::string, nix::AbstractConfig::SettingInfo> settings;
        nix::globalConfig.getSettings(settings);
        if (settings.contains(key))
            return nix_export_std_string(context, settings[key].value, value, n);
        else {
            return nix_set_err_msg(context, NIX_ERR_KEY, "Setting not found");
        }
    }
    NIXC_CATCH_ERRS
}

nix_err nix_setting_set(nix_c_context * context, const char * key, const char * value)
{
    if (context)
        context->last_err_code = NIX_OK;
    if (nix::globalConfig.set(key, value))
        return NIX_OK;
    else {
        return nix_set_err_msg(context, NIX_ERR_KEY, "Setting not found");
    }
}

nix_err nix_libutil_init(nix_c_context * context)
{
    if (context)
        context->last_err_code = NIX_OK;
    try {
        nix::initLibUtil();
        return NIX_OK;
    }
    NIXC_CATCH_ERRS
}

const char * nix_err_msg(nix_c_context * context, const nix_c_context * read_context, unsigned int * n)
{
    if (context)
        context->last_err_code = NIX_OK;
    if (read_context->last_err) {
        if (n)
            *n = read_context->last_err->size();
        return read_context->last_err->c_str();
    }
    nix_set_err_msg(context, NIX_ERR_UNKNOWN, "No error message");
    return nullptr;
}

nix_err nix_err_name(nix_c_context * context, const nix_c_context * read_context, char * value, int n)
{
    if (context)
        context->last_err_code = NIX_OK;
    if (read_context->last_err_code != NIX_ERR_NIX_ERROR) {
        return nix_set_err_msg(context, NIX_ERR_UNKNOWN, "Last error was not a nix error");
    }
    return nix_export_std_string(context, read_context->name, value, n);
}

nix_err nix_err_info_msg(nix_c_context * context, const nix_c_context * read_context, char * value, int n)
{
    if (context)
        context->last_err_code = NIX_OK;
    if (read_context->last_err_code != NIX_ERR_NIX_ERROR) {
        return nix_set_err_msg(context, NIX_ERR_UNKNOWN, "Last error was not a nix error");
    }
    return nix_export_std_string(context, read_context->info->msg.str(), value, n);
}

nix_err nix_err_code(const nix_c_context * read_context)
{
    return read_context->last_err_code;
}

// internal
nix_err nix_export_std_string(nix_c_context * context, const std::string_view str, char * dest, unsigned int n)
{
    size_t i = str.copy(dest, n - 1);
    dest[i] = 0;
    if (i == n - 1) {
        return nix_set_err_msg(context, NIX_ERR_OVERFLOW, "Provided buffer too short");
    } else
        return NIX_OK;
}