badvpn/ncd/modules/call2.c

/**
 * @file call2.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:
 *   call(string template, list args)
 *   embcall2_multif(string cond1, string template1, ..., [string else_template])
 */

#include <stdlib.h>
#include <string.h>

#include <misc/debug.h>
#include <misc/offset.h>
#include <ncd/NCDModule.h>
#include <ncd/static_strings.h>
#include <ncd/extra/value_utils.h>

#include <generated/blog_channel_ncd_call2.h>

#define ModuleLog(i, ...) NCDModuleInst_Backend_Log((i), BLOG_CURRENT_CHANNEL, __VA_ARGS__)

#define STATE_WORKING 1
#define STATE_UP 2
#define STATE_WAITING 3
#define STATE_TERMINATING 4
#define STATE_NONE 5

struct instance {
    NCDModuleInst *i;
    NCDModuleProcess process;
    int embed;
    int state;
};

static void process_handler_event (NCDModuleProcess *process, int event);
static int process_func_getspecialobj (NCDModuleProcess *process, NCD_string_id_t name, NCDObject *out_object);
static int caller_obj_func_getobj (const NCDObject *obj, NCD_string_id_t name, NCDObject *out_object);
static void func_new_templ (void *vo, NCDModuleInst *i, NCDValRef template_name, NCDValRef args, int embed);
static void instance_free (struct instance *o);

enum {STRING_CALLER};

static struct NCD_string_request strings[] = {
    {"_caller"}, {NULL}
};

static void process_handler_event (NCDModuleProcess *process, int event)
{
    struct instance *o = UPPER_OBJECT(process, struct instance, process);
    
    switch (event) {
        case NCDMODULEPROCESS_EVENT_UP: {
            ASSERT(o->state == STATE_WORKING)
            
            // signal up
            NCDModuleInst_Backend_Up(o->i);
            
            // set state up
            o->state = STATE_UP;
        } break;
        
        case NCDMODULEPROCESS_EVENT_DOWN: {
            ASSERT(o->state == STATE_UP)
            
            // signal down
            NCDModuleInst_Backend_Down(o->i);
            
            // set state waiting
            o->state = STATE_WAITING;
        } break;
        
        case NCDMODULEPROCESS_EVENT_TERMINATED: {
            ASSERT(o->state == STATE_TERMINATING)
            
            // die finally
            instance_free(o);
            return;
        } break;
        
        default: ASSERT(0);
    }
}

static int process_func_getspecialobj (NCDModuleProcess *process, NCD_string_id_t name, NCDObject *out_object)
{
    struct instance *o = UPPER_OBJECT(process, struct instance, process);
    
    if (o->embed) {
        return NCDModuleInst_Backend_GetObj(o->i, name, out_object);
    }
    
    if (name == strings[STRING_CALLER].id) {
        *out_object = NCDObject_Build(-1, o, NCDObject_no_getvar, caller_obj_func_getobj);
        return 1;
    }
    
    return 0;
}

static int caller_obj_func_getobj (const NCDObject *obj, NCD_string_id_t name, NCDObject *out_object)
{
    struct instance *o = NCDObject_DataPtr(obj);
    
    return NCDModuleInst_Backend_GetObj(o->i, name, out_object);
}

static void func_new_templ (void *vo, NCDModuleInst *i, NCDValRef template_name, NCDValRef args, int embed)
{
    ASSERT(NCDVal_IsInvalid(template_name) || NCDVal_IsString(template_name))
    ASSERT(NCDVal_IsInvalid(args) || NCDVal_IsList(args))
    ASSERT(embed == !!embed)
    
    struct instance *o = vo;
    o->i = i;
    
    // remember embed
    o->embed = embed;
    
    if (NCDVal_IsInvalid(template_name) || ncd_is_none(template_name)) {
        // signal up
        NCDModuleInst_Backend_Up(o->i);
        
        // set state none
        o->state = STATE_NONE;
    } else {
        // create process
        if (!NCDModuleProcess_InitValue(&o->process, o->i, template_name, args, process_handler_event)) {
            ModuleLog(o->i, BLOG_ERROR, "NCDModuleProcess_Init failed");
            goto fail0;
        }
        
        // set special functions
        NCDModuleProcess_SetSpecialFuncs(&o->process, process_func_getspecialobj);
        
        // set state working
        o->state = STATE_WORKING;
    }
    
    return;
    
fail0:
    NCDModuleInst_Backend_DeadError(i);
}

static void instance_free (struct instance *o)
{
    // free process
    if (o->state != STATE_NONE) {
        NCDModuleProcess_Free(&o->process);
    }
    
    NCDModuleInst_Backend_Dead(o->i);
}

static void func_new_call (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
    NCDValRef template_arg;
    NCDValRef args_arg;
    if (!NCDVal_ListRead(params->args, 2, &template_arg, &args_arg)) {
        ModuleLog(i, BLOG_ERROR, "wrong arity");
        goto fail0;
    }
    if (!NCDVal_IsString(template_arg) || !NCDVal_IsList(args_arg)) {
        ModuleLog(i, BLOG_ERROR, "wrong type");
        goto fail0;
    }
    
    func_new_templ(vo, i, template_arg, args_arg, 0);
    return;
    
fail0:
    NCDModuleInst_Backend_DeadError(i);
}

static void func_new_embcall_multif (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
    NCDValRef args = params->args;
    
    NCDValRef template_value = NCDVal_NewInvalid();
    
    size_t count = NCDVal_ListCount(args);
    size_t j = 0;
    
    while (j < count) {
        NCDValRef arg = NCDVal_ListGet(args, j);
        
        if (j == count - 1) {
            if (!NCDVal_IsString(arg)) {
                ModuleLog(i, BLOG_ERROR, "bad arguments");
                goto fail0;
            }
            
            template_value = arg;
            break;
        }
        
        NCDValRef arg2 = NCDVal_ListGet(args, j + 1);
        
        if (!NCDVal_IsString(arg) || !NCDVal_IsString(arg2)) {
            ModuleLog(i, BLOG_ERROR, "bad arguments");
            goto fail0;
        }
        
        if (ncd_read_boolean(arg)) {
            template_value = arg2;
            break;
        }
        
        j += 2;
    }
    
    func_new_templ(vo, i, template_value, NCDVal_NewInvalid(), 1);
    return;
    
fail0:
    NCDModuleInst_Backend_DeadError(i);
}

static void func_die (void *vo)
{
    struct instance *o = vo;
    ASSERT(o->state != STATE_TERMINATING)
    
    // if none, die now
    if (o->state == STATE_NONE) {
        instance_free(o);
        return;
    }
    
    // request process to terminate
    NCDModuleProcess_Terminate(&o->process);
    
    // set state terminating
    o->state = STATE_TERMINATING;
}

static void func_clean (void *vo)
{
    struct instance *o = vo;
    if (o->state != STATE_WAITING) {
        return;
    }
    
    // allow process to continue
    NCDModuleProcess_Continue(&o->process);
    
    // set state working
    o->state = STATE_WORKING;
}

static int func_getobj (void *vo, NCD_string_id_t name, NCDObject *out_object)
{
    struct instance *o = vo;
    
    if (o->state == STATE_NONE) {
        return 0;
    }
    
    return NCDModuleProcess_GetObj(&o->process, name, out_object);
}

static struct NCDModule modules[] = {
    {
        .type = "call",
        .func_new2 = func_new_call,
        .func_die = func_die,
        .func_clean = func_clean,
        .func_getobj = func_getobj,
        .flags = NCDMODULE_FLAG_CAN_RESOLVE_WHEN_DOWN,
        .alloc_size = sizeof(struct instance)
    }, {
        .type = "embcall2_multif",
        .func_new2 = func_new_embcall_multif,
        .func_die = func_die,
        .func_clean = func_clean,
        .func_getobj = func_getobj,
        .flags = NCDMODULE_FLAG_CAN_RESOLVE_WHEN_DOWN,
        .alloc_size = sizeof(struct instance)
    }, {
        .type = NULL
    }
};

const struct NCDModuleGroup ncdmodule_call2 = {
    .modules = modules,
    .strings = strings
};