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/**
* @file spawn.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
*
* Module which starts a process from a process template on initialization, and
* stops it on deinitialization.
*
* Synopsis:
* spawn(string template_name, list args)
*
* Description:
* On initialization, creates a new process from the template named
* 'template_name', with arguments 'args'. On deinitialization, initiates termination
* of the process and waits for it to terminate. The process can access objects
* as seen from 'spawn' via the _caller special object.
*
* Synopsis:
* spawn::join()
*
* Description:
* A join() on a spawn() is like a depend() on a provide() which is located at the
* end of the spawned process.
*
* Variables:
* Exposes objects from the spawned process.
*/
#include <stdlib.h>
#include <string.h>
#include <misc/offset.h>
#include <misc/debug.h>
#include <structure/LinkedList0.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_spawn.h>
#define STATE_WORKING 1
#define STATE_UP 2
#define STATE_WAITING 3
#define STATE_WAITING_TERMINATING 4
#define STATE_TERMINATING 5
struct instance {
NCDModuleInst *i;
NCDModuleProcess process;
LinkedList0 clean_list;
LinkedList0 dirty_list;
int state;
};
struct join_instance {
NCDModuleInst *i;
struct instance *spawn;
LinkedList0Node list_node;
int is_dirty;
};
static void assert_dirty_state (struct instance *o);
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 bring_joins_down (struct instance *o);
static void continue_working (struct instance *o);
static void continue_terminating (struct instance *o);
static void instance_free (struct instance *o);
static void assert_dirty_state (struct instance *o)
{
ASSERT(!LinkedList0_IsEmpty(&o->dirty_list) == (o->state == STATE_WAITING || o->state == STATE_WAITING_TERMINATING))
}
static void process_handler_event (NCDModuleProcess *process, int event)
{
struct instance *o = UPPER_OBJECT(process, struct instance, process);
assert_dirty_state(o);
switch (event) {
case NCDMODULEPROCESS_EVENT_UP: {
ASSERT(o->state == STATE_WORKING)
ASSERT(LinkedList0_IsEmpty(&o->dirty_list))
// set state up
o->state = STATE_UP;
// bring joins up
for (LinkedList0Node *ln = LinkedList0_GetFirst(&o->clean_list); ln; ln = LinkedList0Node_Next(ln)) {
struct join_instance *join = UPPER_OBJECT(ln, struct join_instance, list_node);
ASSERT(join->spawn == o)
ASSERT(!join->is_dirty)
NCDModuleInst_Backend_Up(join->i);
}
} break;
case NCDMODULEPROCESS_EVENT_DOWN: {
ASSERT(o->state == STATE_UP)
ASSERT(LinkedList0_IsEmpty(&o->dirty_list))
// bring joins down, moving them to the dirty list
bring_joins_down(o);
// set state waiting
o->state = STATE_WAITING;
// if we have no joins, continue immediately
if (LinkedList0_IsEmpty(&o->dirty_list)) {
continue_working(o);
return;
}
} break;
case NCDMODULEPROCESS_EVENT_TERMINATED: {
ASSERT(o->state == STATE_TERMINATING)
ASSERT(LinkedList0_IsEmpty(&o->dirty_list))
// 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 (name == NCD_STRING_CALLER) {
*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 bring_joins_down (struct instance *o)
{
LinkedList0Node *ln;
while (ln = LinkedList0_GetFirst(&o->clean_list)) {
struct join_instance *join = UPPER_OBJECT(ln, struct join_instance, list_node);
ASSERT(join->spawn == o)
ASSERT(!join->is_dirty)
NCDModuleInst_Backend_Down(join->i);
LinkedList0_Remove(&o->clean_list, &join->list_node);
LinkedList0_Prepend(&o->dirty_list, &join->list_node);
join->is_dirty = 1;
}
}
static void continue_working (struct instance *o)
{
ASSERT(o->state == STATE_WAITING)
ASSERT(LinkedList0_IsEmpty(&o->dirty_list))
// continue process
NCDModuleProcess_Continue(&o->process);
// set state working
o->state = STATE_WORKING;
}
static void continue_terminating (struct instance *o)
{
ASSERT(o->state == STATE_WAITING_TERMINATING)
ASSERT(LinkedList0_IsEmpty(&o->dirty_list))
// request process to terminate
NCDModuleProcess_Terminate(&o->process);
// set state terminating
o->state = STATE_TERMINATING;
}
static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct instance *o = vo;
o->i = i;
// check arguments
NCDValRef template_name_arg;
NCDValRef args_arg;
if (!NCDVal_ListRead(params->args, 2, &template_name_arg, &args_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsString(template_name_arg) || !NCDVal_IsList(args_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail0;
}
// signal up.
// Do it before creating the process so that the process starts initializing before our own process continues.
NCDModuleInst_Backend_Up(o->i);
// create process
if (!NCDModuleProcess_InitValue(&o->process, o->i, template_name_arg, args_arg, process_handler_event)) {
ModuleLog(o->i, BLOG_ERROR, "NCDModuleProcess_Init failed");
goto fail0;
}
// set object resolution function
NCDModuleProcess_SetSpecialFuncs(&o->process, process_func_getspecialobj);
// init lists
LinkedList0_Init(&o->clean_list);
LinkedList0_Init(&o->dirty_list);
// set state working
o->state = STATE_WORKING;
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
void instance_free (struct instance *o)
{
ASSERT(LinkedList0_IsEmpty(&o->dirty_list))
// unlink joins
LinkedList0Node *ln;
while (ln = LinkedList0_GetFirst(&o->clean_list)) {
struct join_instance *join = UPPER_OBJECT(ln, struct join_instance, list_node);
ASSERT(join->spawn == o)
ASSERT(!join->is_dirty)
LinkedList0_Remove(&o->clean_list, &join->list_node);
join->spawn = NULL;
}
// free process
NCDModuleProcess_Free(&o->process);
NCDModuleInst_Backend_Dead(o->i);
}
static void func_die (void *vo)
{
struct instance *o = vo;
ASSERT(o->state != STATE_WAITING_TERMINATING)
ASSERT(o->state != STATE_TERMINATING)
assert_dirty_state(o);
// bring joins down
if (o->state == STATE_UP) {
bring_joins_down(o);
}
// set state waiting terminating
o->state = STATE_WAITING_TERMINATING;
// start terminating now if possible
if (LinkedList0_IsEmpty(&o->dirty_list)) {
continue_terminating(o);
return;
}
}
static void join_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct join_instance *o = vo;
o->i = i;
if (!NCDVal_ListRead(params->args, 0)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail0;
}
o->spawn = NCDModuleInst_Backend_GetUser((NCDModuleInst *)params->method_user);
assert_dirty_state(o->spawn);
LinkedList0_Prepend(&o->spawn->clean_list, &o->list_node);
o->is_dirty = 0;
if (o->spawn->state == STATE_UP) {
NCDModuleInst_Backend_Up(i);
}
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void join_func_die (void *vo)
{
struct join_instance *o = vo;
if (o->spawn) {
assert_dirty_state(o->spawn);
// remove from list
if (o->is_dirty) {
LinkedList0_Remove(&o->spawn->dirty_list, &o->list_node);
} else {
LinkedList0_Remove(&o->spawn->clean_list, &o->list_node);
}
if (o->is_dirty && LinkedList0_IsEmpty(&o->spawn->dirty_list)) {
ASSERT(o->spawn->state == STATE_WAITING || o->spawn->state == STATE_WAITING_TERMINATING)
if (o->spawn->state == STATE_WAITING) {
continue_working(o->spawn);
} else {
continue_terminating(o->spawn);
}
}
}
NCDModuleInst_Backend_Dead(o->i);
}
static int join_func_getobj (void *vo, NCD_string_id_t name, NCDObject *out)
{
struct join_instance *o = vo;
if (!o->spawn) {
return 0;
}
return NCDModuleProcess_GetObj(&o->spawn->process, name, out);
}
static void join_func_clean (void *vo)
{
struct join_instance *o = vo;
if (!(o->spawn && o->is_dirty)) {
return;
}
assert_dirty_state(o->spawn);
ASSERT(o->spawn->state == STATE_WAITING || o->spawn->state == STATE_WAITING_TERMINATING)
LinkedList0_Remove(&o->spawn->dirty_list, &o->list_node);
LinkedList0_Prepend(&o->spawn->clean_list, &o->list_node);
o->is_dirty = 0;
if (LinkedList0_IsEmpty(&o->spawn->dirty_list)) {
if (o->spawn->state == STATE_WAITING) {
continue_working(o->spawn);
} else {
continue_terminating(o->spawn);
}
}
}
static struct NCDModule modules[] = {
{
.type = "spawn",
.func_new2 = func_new,
.func_die = func_die,
.alloc_size = sizeof(struct instance)
}, {
.type = "synchronous_process", // deprecated name
.func_new2 = func_new,
.func_die = func_die,
.alloc_size = sizeof(struct instance)
}, {
.type = "spawn::join",
.func_new2 = join_func_new,
.func_die = join_func_die,
.func_getobj = join_func_getobj,
.func_clean = join_func_clean,
.alloc_size = sizeof(struct join_instance),
.flags = NCDMODULE_FLAG_CAN_RESOLVE_WHEN_DOWN
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_spawn = {
.modules = modules
};