kea/src/lib/hooks/tests/load_callout_library.cc

// Copyright (C) 2013-2015 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

/// @file
/// @brief Basic library with load() function
///
/// This is source of a test library for various test (LibraryManager and
/// HooksManager).  The characteristics of the library produced from this
/// file are:
///
/// - The "version" and "load" framework functions are supplied.  One "standard"
///   callout is supplied ("hookpt_one") and two non-standard ones which are
///   registered during the call to "load" on the hooks "hookpt_two" and
///   "hookpt_three".
///
///   All callouts do trivial calculations, the result of all being called in
///   sequence being
///
///   @f[ ((5 * data_1) + data_2) * data_3 @f]
///
///   ...where data_1, data_2 and data_3 are the values passed in arguments of
///   the same name to the three callouts (data_1 passed to hookpt_one, data_2
///   to hookpt_two etc.) and the result is returned in the argument "result".

#include <config.h>
#include <hooks/hooks.h>

using namespace isc::hooks;

extern "C" {

// Callouts

int
context_create(CalloutHandle& handle) {
    handle.setContext("result", static_cast<int>(5));
    handle.setArgument("result", static_cast<int>(5));
    return (0);
}

// First callout adds the passed "data_1" argument to the initialized context
// value of 5. (Note that the value set by context_create is accessed through
// context and not the argument, so checking that context is correctly passed
// between callouts in the same library.)

int
hookpt_one(CalloutHandle& handle) {
    int data;
    handle.getArgument("data_1", data);

    int result;
    handle.getContext("result", result);

    result *= data;
    handle.setArgument("result", result);

    return (0);
}

// Second callout multiplies the current context value by the "data_2"
// argument.

static int
hook_nonstandard_two(CalloutHandle& handle) {
    int data;
    handle.getArgument("data_2", data);

    int result;
    handle.getArgument("result", result);

    result += data;
    handle.setArgument("result", result);

    return (0);
}

// Final callout adds "data_3" to the result.

static int
hook_nonstandard_three(CalloutHandle& handle) {
    int data;
    handle.getArgument("data_3", data);

    int result;
    handle.getArgument("result", result);

    result *= data;
    handle.setArgument("result", result);

    return (0);
}

// Framework functions

int
version() {
    return (KEA_HOOKS_VERSION);
}

int load(LibraryHandle& handle) {
    // Initialize the user library if the main image was statically linked
#ifdef USE_STATIC_LINK
    hooksStaticLinkInit();
#endif
    // Register the non-standard functions
    handle.registerCallout("hookpt_two", hook_nonstandard_two);
    handle.registerCallout("hookpt_three", hook_nonstandard_three);

    return (0);
}

};