372 lines
11 KiB
C
372 lines
11 KiB
C
/**
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* @file ondemand.c
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @section DESCRIPTION
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*
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* On-demand process manager.
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*
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* Synopsis:
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* ondemand(string template_name, list args)
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*
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* Description:
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* Manages an on-demand template process using a process template named
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* template_name.
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* On deinitialization, if the process is running, reqests its termination
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* and waits for it to terminate.
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*
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* Synopsis:
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* ondemand::demand()
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*
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* Description:
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* Demands the availability of an on-demand template process.
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* This statement is in UP state if and only if the template process of the
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* corresponding ondemand object is completely up.
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*
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* Variables:
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* Exposes variables and objects from the template process corresponding to
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* the ondemand object.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <misc/offset.h>
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#include <misc/debug.h>
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#include <structure/LinkedList1.h>
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#include <ncd/module_common.h>
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#include <generated/blog_channel_ncd_ondemand.h>
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struct ondemand {
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NCDModuleInst *i;
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NCDValRef template_name;
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NCDValRef args;
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LinkedList1 demands_list;
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int dying;
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int have_process;
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NCDModuleProcess process;
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int process_terminating;
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int process_up;
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};
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struct demand {
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NCDModuleInst *i;
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struct ondemand *od;
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LinkedList1Node demands_list_node;
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};
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static int ondemand_start_process (struct ondemand *o);
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static void ondemand_terminate_process (struct ondemand *o);
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static void ondemand_process_handler (NCDModuleProcess *process, int event);
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static void ondemand_free (struct ondemand *o);
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static void demand_free (struct demand *o, int is_error);
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static int ondemand_start_process (struct ondemand *o)
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{
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ASSERT(!o->dying)
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ASSERT(!o->have_process)
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// start process
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if (!NCDModuleProcess_InitValue(&o->process, o->i, o->template_name, o->args, ondemand_process_handler)) {
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ModuleLog(o->i, BLOG_ERROR, "NCDModuleProcess_Init failed");
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goto fail0;
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}
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// set have process
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o->have_process = 1;
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// set process not terminating
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o->process_terminating = 0;
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// set process not up
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o->process_up = 0;
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return 1;
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fail0:
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return 0;
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}
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static void ondemand_terminate_process (struct ondemand *o)
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{
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ASSERT(o->have_process)
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ASSERT(!o->process_terminating)
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// request termination
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NCDModuleProcess_Terminate(&o->process);
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// set process terminating
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o->process_terminating = 1;
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if (o->process_up) {
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// set process down
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o->process_up = 0;
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// signal demands down
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for (LinkedList1Node *n = LinkedList1_GetFirst(&o->demands_list); n; n = LinkedList1Node_Next(n)) {
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struct demand *demand = UPPER_OBJECT(n, struct demand, demands_list_node);
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ASSERT(demand->od == o)
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NCDModuleInst_Backend_Down(demand->i);
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}
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}
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}
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static void ondemand_process_handler (NCDModuleProcess *process, int event)
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{
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struct ondemand *o = UPPER_OBJECT(process, struct ondemand, process);
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ASSERT(o->have_process)
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switch (event) {
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case NCDMODULEPROCESS_EVENT_UP: {
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ASSERT(!o->process_terminating)
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ASSERT(!o->process_up)
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// set process up
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o->process_up = 1;
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// signal demands up
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for (LinkedList1Node *n = LinkedList1_GetFirst(&o->demands_list); n; n = LinkedList1Node_Next(n)) {
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struct demand *demand = UPPER_OBJECT(n, struct demand, demands_list_node);
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ASSERT(demand->od == o)
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NCDModuleInst_Backend_Up(demand->i);
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}
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} break;
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case NCDMODULEPROCESS_EVENT_DOWN: {
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ASSERT(!o->process_terminating)
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ASSERT(o->process_up)
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// continue process
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NCDModuleProcess_Continue(&o->process);
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// set process down
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o->process_up = 0;
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// signal demands down
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for (LinkedList1Node *n = LinkedList1_GetFirst(&o->demands_list); n; n = LinkedList1Node_Next(n)) {
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struct demand *demand = UPPER_OBJECT(n, struct demand, demands_list_node);
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ASSERT(demand->od == o)
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NCDModuleInst_Backend_Down(demand->i);
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}
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} break;
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case NCDMODULEPROCESS_EVENT_TERMINATED: {
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ASSERT(o->process_terminating)
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ASSERT(!o->process_up)
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// free process
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NCDModuleProcess_Free(&o->process);
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// set have no process
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o->have_process = 0;
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// if dying, die finally
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if (o->dying) {
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ondemand_free(o);
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return;
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}
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// if demands arrivied, restart process
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if (!LinkedList1_IsEmpty(&o->demands_list)) {
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if (!ondemand_start_process(o)) {
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// error demands
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while (!LinkedList1_IsEmpty(&o->demands_list)) {
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struct demand *demand = UPPER_OBJECT(LinkedList1_GetFirst(&o->demands_list), struct demand, demands_list_node);
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ASSERT(demand->od == o)
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demand_free(demand, 1);
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}
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}
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}
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} break;
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}
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}
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static void ondemand_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
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{
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struct ondemand *o = vo;
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o->i = i;
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// read arguments
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NCDValRef arg_template_name;
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NCDValRef arg_args;
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if (!NCDVal_ListRead(params->args, 2, &arg_template_name, &arg_args)) {
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ModuleLog(i, BLOG_ERROR, "wrong arity");
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goto fail0;
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}
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if (!NCDVal_IsString(arg_template_name) || !NCDVal_IsList(arg_args)) {
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ModuleLog(i, BLOG_ERROR, "wrong type");
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goto fail0;
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}
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o->template_name = arg_template_name;
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o->args = arg_args;
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// init demands list
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LinkedList1_Init(&o->demands_list);
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// set not dying
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o->dying = 0;
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// set have no process
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o->have_process = 0;
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// signal up
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NCDModuleInst_Backend_Up(i);
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return;
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fail0:
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NCDModuleInst_Backend_DeadError(i);
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}
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static void ondemand_free (struct ondemand *o)
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{
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ASSERT(!o->have_process)
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// die demands
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while (!LinkedList1_IsEmpty(&o->demands_list)) {
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struct demand *demand = UPPER_OBJECT(LinkedList1_GetFirst(&o->demands_list), struct demand, demands_list_node);
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ASSERT(demand->od == o)
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demand_free(demand, 0);
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}
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NCDModuleInst_Backend_Dead(o->i);
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}
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static void ondemand_func_die (void *vo)
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{
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struct ondemand *o = vo;
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ASSERT(!o->dying)
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// if not have process, die right away
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if (!o->have_process) {
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ondemand_free(o);
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return;
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}
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// set dying
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o->dying = 1;
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// request process termination if not already
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if (!o->process_terminating) {
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ondemand_terminate_process(o);
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}
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}
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static void demand_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
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{
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struct demand *o = vo;
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o->i = i;
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// read arguments
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if (!NCDVal_ListRead(params->args, 0)) {
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ModuleLog(i, BLOG_ERROR, "wrong arity");
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goto fail0;
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}
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// set ondemand
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o->od = NCDModuleInst_Backend_GetUser((NCDModuleInst *)params->method_user);
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// add to ondemand's demands list
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LinkedList1_Append(&o->od->demands_list, &o->demands_list_node);
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// start process if needed
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if (!o->od->have_process) {
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ASSERT(!o->od->dying)
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if (!ondemand_start_process(o->od)) {
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goto fail1;
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}
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}
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// if process is up, signal up
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if (o->od->process_up) {
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NCDModuleInst_Backend_Up(i);
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}
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return;
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fail1:
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LinkedList1_Remove(&o->od->demands_list, &o->demands_list_node);
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fail0:
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NCDModuleInst_Backend_DeadError(i);
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}
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static void demand_free (struct demand *o, int is_error)
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{
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// remove from ondemand's demands list
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LinkedList1_Remove(&o->od->demands_list, &o->demands_list_node);
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// request process termination if no longer needed
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if (o->od->have_process && !o->od->process_terminating && LinkedList1_IsEmpty(&o->od->demands_list)) {
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ondemand_terminate_process(o->od);
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}
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if (is_error) {
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NCDModuleInst_Backend_DeadError(o->i);
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} else {
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NCDModuleInst_Backend_Dead(o->i);
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}
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}
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static void demand_func_die (void *vo)
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{
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struct demand *o = vo;
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demand_free(o, 0);
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}
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static int demand_func_getobj (void *vo, NCD_string_id_t objname, NCDObject *out_object)
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{
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struct demand *o = vo;
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ASSERT(o->od->have_process)
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ASSERT(o->od->process_up)
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return NCDModuleProcess_GetObj(&o->od->process, objname, out_object);
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}
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static struct NCDModule modules[] = {
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{
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.type = "ondemand",
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.func_new2 = ondemand_func_new,
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.func_die = ondemand_func_die,
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.alloc_size = sizeof(struct ondemand)
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}, {
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.type = "ondemand::demand",
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.func_new2 = demand_func_new,
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.func_die = demand_func_die,
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.func_getobj = demand_func_getobj,
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.alloc_size = sizeof(struct demand)
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}, {
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.type = NULL
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}
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};
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const struct NCDModuleGroup ncdmodule_ondemand = {
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.modules = modules
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};
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