LeOS-Genesis/external/badvpn/ncd/modules/backtrack.c

104 lines
3.4 KiB
C

/**
* @file backtrack.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Synopsis:
* backtrack_point()
* backtrack_point::go()
*
* Description:
* The backtrack_point() statement creates a backtrack point, going up immedietely.
* The go() method triggers backtracking to the backtrack point, i.e. makes the
* backtrack_point() statement go down and back up at atomically. The go() method
* itself goes up immedietely, but side effects of triggering backtracking have
* priority.
*/
#include <stddef.h>
#include <ncd/NCDModule.h>
#include <generated/blog_channel_ncd_backtrack.h>
#define ModuleLog(i, ...) NCDModuleInst_Backend_Log((i), BLOG_CURRENT_CHANNEL, __VA_ARGS__)
static void func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
// check arguments
if (!NCDVal_ListRead(params->args, 0)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
// go up
NCDModuleInst_Backend_Up(i);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void go_func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
// check arguments
if (!NCDVal_ListRead(params->args, 0)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
// get backtrack point
NCDModuleInst *backtrack_point_inst = params->method_user;
// go up (after toggling)
NCDModuleInst_Backend_Up(i);
// toggle backtrack point
NCDModuleInst_Backend_DownUp(backtrack_point_inst);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static struct NCDModule modules[] = {
{
.type = "backtrack_point",
.func_new2 = func_new
}, {
.type = "backtrack_point::go",
.func_new2 = go_func_new
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_backtrack = {
.modules = modules
};