stasis-aries-wal/src/2pc/2pc.c

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---*/
#include "2pc.h"
#include <assert.h>
#include <string.h>
#include "../libdfa/callbacks.h"

#define TRUE  1
#define FALSE 0
/* #define _TWO_PC 1 */

const int transition_count_2pc = 14;
const int client_transition_count_2pc = 4;
const int state_count_2pc = 9;



callback_fcn check_veto_2pc;
callback_fcn tally_2pc;
callback_fcn send_ack_2pc;
callback_fcn coordinator_init_xact_2pc; 
callback_fcn veto_or_prepare_2pc;
callback_fcn abort_2pc;
callback_fcn commit_2pc;


/* Remember to update transition_count_2pc if you add/remove transitions */
Transition transitions_2pc[] = {

  /* Coordinator transitions */

  /* Library user must provide callback that init_xact_2pc calls. */
  { AWAIT_ARRIVAL,            NULL_STATE,                 COORDINATOR_START_2PC,      coordinator_init_xact_2pc,       FALSE },
  { AWAIT_COMMIT_POINT,       NULL_STATE,                 COORDINATOR_START_2PC,      coordinator_init_xact_2pc,       FALSE },
  { AWAIT_RESULT,             NULL_STATE,                 COORDINATOR_START_2PC,      coordinator_init_xact_2pc,       FALSE },
  { NULL_STATE,               NULL_STATE,                 COORDINATOR_START_2PC,      coordinator_init_xact_2pc,       FALSE },

  /* TODO: tally_2pc and check_veto_2pc should respond to initiator where applicable. */
  { SUBORDINATE_VETO_2PC,     COORDINATOR_START_2PC,      COORDINATOR_ABORTING_2PC,   &check_veto_2pc,      TRUE }, 
  { SUBORDINATE_PREPARED_2PC, COORDINATOR_START_2PC,      COORDINATOR_COMMITTING_2PC, &tally_2pc,           TRUE }, 
  { SUBORDINATE_ACKING_2PC,   COORDINATOR_ABORTING_2PC,   NULL_STATE,                 &tally_2pc,           FALSE},
  { SUBORDINATE_ACKING_2PC,   COORDINATOR_COMMITTING_2PC, NULL_STATE,                 &tally_2pc,           FALSE},

  /* Subordinate transitions */
      /* veto_or_prepare overrides target state. */

  /* Library user must provide the subordinate function pointers for these transitions */
  { COORDINATOR_START_2PC,      NULL_STATE,               OVERRIDDEN_STATE,           &veto_or_prepare_2pc, TRUE },
  { COORDINATOR_ABORTING_2PC,   SUBORDINATE_PREPARED_2PC, NULL_STATE,                 &abort_2pc,           FALSE}, 
  { COORDINATOR_COMMITTING_2PC, SUBORDINATE_PREPARED_2PC, NULL_STATE,                 &commit_2pc,          FALSE},
  { COORDINATOR_ABORTING_2PC,   SUBORDINATE_VETO_2PC,     NULL_STATE,                 NULL,                 FALSE},

  /* transition fcn always fails, but sends ack to coordinator */
  { COORDINATOR_COMMITTING_2PC, NULL_STATE,               OVERRIDDEN_STATE,           &send_ack_2pc,        TRUE}, 
  { COORDINATOR_ABORTING_2PC,   NULL_STATE,               OVERRIDDEN_STATE,           &send_ack_2pc,        TRUE}, 

  

   
};

Transition client_transitions_2pc[] = {

 /* Caller transitions */

  { COORDINATOR_START_2PC,      AWAIT_ARRIVAL,          NULL_STATE,   NULL, FALSE},

  { COORDINATOR_COMMITTING_2PC, AWAIT_COMMIT_POINT,     NULL_STATE,   NULL, FALSE},
  { COORDINATOR_ABORTING_2PC,   AWAIT_COMMIT_POINT,     NULL_STATE,   NULL, FALSE},
  
  { SUBORDINATE_ACKING_2PC,     AWAIT_RESULT,           NULL_STATE,   NULL, FALSE},
  


};


State states_2pc[MAX_STATE_COUNT] = {

/* Coordinator states */

  { COORDINATOR_START_2PC,      NULL, NULL },  /* Need abort fcn */
  { COORDINATOR_COMMITTING_2PC, NULL, NULL },
  { COORDINATOR_ABORTING_2PC,   NULL, NULL },

/* Subordinate states */

  { SUBORDINATE_VETO_2PC,       NULL, NULL },  /* Need to think about callback fcns */
  { SUBORDINATE_PREPARED_2PC,   NULL, NULL },
  { SUBORDINATE_ACKING_2PC,     NULL, NULL },

  /* Client states */

  { AWAIT_ARRIVAL,      NULL, NULL},
  { AWAIT_RESULT,       NULL, NULL},
  { AWAIT_COMMIT_POINT, NULL, NULL},

};




/* 

   - add broadcast to messages.h  (Done)
   - change libdfa so that it scans the states array (Done)
   - add support for OVERRIDDEN_STATE to libdfa (Done, test it)
   - add support for transactions to libdfa (Need to replace monotree)
   - write the callback fcns. (~Done, test it!)

*/


/* Probably should ack the client that called commit(), instead of
   hoping that UDP got it here for them... ;) So, they should have a
   state machine that initiated the transaction, and waits for an ACK
   or NAK from us. */
state_name coordinator_init_xact_2pc(void * dfaSet, StateMachine * stateMachine, Message * m, char * from) {
  TwoPCMachineState * state = (TwoPCMachineState*) &(stateMachine->app_state);
  TwoPCAppState * app_state = ((TwoPCAppState*)(((DfaSet*)dfaSet)->app_setup));
  short bc_group = app_state->get_broadcast_group(dfaSet, m);
  int ret;

  if(!app_state->is_coordinator) {
    return 0;
  }
  
  printf("bc_group %d\n", bc_group);

  /* Need to check for this somewhere... */
  assert(sizeof(TwoPCAppState) <= MAX_APP_STATE_SIZE);

  memset(state->subordinate_votes, 0, MAX_SUBORDINATES);
  /*  state->xid = m->from_machine_id; */
  state->xid = stateMachine->machine_id;
  printf("From: %s", from);
  /*strncpy(state->initiator, from, MAX_ADDRESS_LENGTH);*/

  sprintf(from, "bc:%d\n", bc_group);

  /* TODO:  (n)ack the client.  (Implies yes / no / already pending return values for callback on last line)
     Currently, this is handled by the library user.  It could be moved back into here.

  */
  if(app_state->init_xact_2pc != NULL) {
    ret = app_state->init_xact_2pc(dfaSet, stateMachine, m, from);
  } else {
    ret = 1;
  }

  if(m->type==AWAIT_ARRIVAL && ret) {
    // need to (n)ack the client:
    // Respond using the machine id expected by the client.
    m->from_machine_id = m->initiator_machine_id;

    printf("Responding\n");
    
    respond_once(&((DfaSet*)dfaSet)->networkSetup, 
    		 COORDINATOR_START_2PC, m, m->initiator);
  }

  m->from_machine_id = stateMachine->machine_id;

  return ret;


}
state_name send_ack_2pc(void * dfaSet, StateMachine * stateMachine, Message * m, char * from) {
  respond_once(&((DfaSet*)dfaSet)->networkSetup, SUBORDINATE_ACKING_2PC, m, from);
  return OVERRIDDEN_STATE;
}

/**
   TODO: Can this be done in a way that avoids blocking?
*/
state_name veto_or_prepare_2pc(void * dfaSet, StateMachine * stateMachine, Message * m, char * from) {
  TwoPCAppState * app_state = ((TwoPCAppState*)(((DfaSet*)dfaSet)->app_setup));

  int ret = app_state->veto_or_prepare_2pc(dfaSet, stateMachine, m, from);
  
  return ret;
}

/**
   TODO:  The next two functions should fork and immediately return true.
*/

state_name abort_2pc(void * dfaSet, StateMachine * stateMachine, Message * m, char * from) {
  TwoPCAppState * app_state = ((TwoPCAppState*)(((DfaSet*)dfaSet)->app_setup));
  send_ack_2pc(dfaSet, stateMachine, m, from);
  int ret = app_state->abort_2pc(dfaSet, stateMachine, m, from);

  //if((*responseType(m) == AWAIT_COMMIT_POINT || *responseType(m) == AWAIT_RESULT)) {
  if(m->response_type == AWAIT_COMMIT_POINT || m->response_type == AWAIT_RESULT) {
    state_machine_id tmp = m->from_machine_id;

    /* TODO:  Could the chages to from_machine_id be moved into libdfa (it does this anyway, but it does it too late.) */
    m->from_machine_id = m->initiator_machine_id; /*stateMachine->machine_id;*/

    printf("Response being sent to: %s:%ld\n", m->initiator, m->to_machine_id);
    respond_once(&((DfaSet*)dfaSet)->networkSetup, SUBORDINATE_VETO_2PC, m, m->initiator);
    m->from_machine_id = tmp;
  }
  return ret;
}

state_name commit_2pc(void * dfaSet, StateMachine * stateMachine, Message * m, char * from) {
  TwoPCAppState * app_state = ((TwoPCAppState*)(((DfaSet*)dfaSet)->app_setup));

  send_ack_2pc(dfaSet, stateMachine, m, from);
  return app_state->commit_2pc(dfaSet, stateMachine, m, from);
}

state_name check_veto_2pc(void * dfaSet, StateMachine * stateMachine, Message * m, char * from) {
  /* Clear subordinate_votes array, so that it can be used to
     tally acks after the votes are tallied. */

  TwoPCAppState * app_state = ((TwoPCAppState*)(((DfaSet*)dfaSet)->app_setup));
  TwoPCMachineState * machine_state = (TwoPCMachineState*)&(stateMachine->app_state);

  /* if (!check_from()) { return 0; } */
  short bc_group = app_state->get_broadcast_group(dfaSet, m);
  
  printf("bc_group:veto %d\n", bc_group);

  memset(machine_state->subordinate_votes, 0, MAX_SUBORDINATES);
  sprintf(from, "bc:%d", bc_group);

  return 1;
}

state_name tally_2pc(void * dfaSetPtr, StateMachine * stateMachine, Message * m, char * from) {

  TwoPCMachineState * machine_state = (TwoPCMachineState*)&(stateMachine->app_state);
  DfaSet * dfaSet = (DfaSet*) dfaSetPtr;

  TwoPCAppState * app_state = ((TwoPCAppState*)(((DfaSet*)dfaSet)->app_setup));

  /* if (!check_from()) { return 0; } */
  short bc_group = app_state->get_broadcast_group(dfaSet, m);

  if(bc_group < dfaSet->networkSetup.broadcast_lists_count) {
    state_name ret = tally(dfaSet->networkSetup.broadcast_lists[bc_group],
		 dfaSet->networkSetup.broadcast_list_host_count[bc_group],
		 (char*)(machine_state->subordinate_votes), from);
    if(ret) {
      /* Clear subordinate_votes array, so that it can be used to
	 tally acks after the votes are tallied. */
      memset(machine_state->subordinate_votes, 0, MAX_SUBORDINATES);
    }


    /* Needed to use the from variable to do the tally, so this
       sprintf needs to be down here. */

    sprintf(from, "bc:%d", bc_group);

    if(ret && app_state->tally_2pc != NULL) {  
      ret = app_state->tally_2pc(dfaSet, stateMachine, m, from);
    }
  /* TODO: CORRECTNESS BUG Make sure this is after tally forces the log. Also, need to
     make sure that it increments the (currently unimplemented)
     sequence number before flushing... */

    if(ret && (m->response_type == AWAIT_COMMIT_POINT && m->response_type == COORDINATOR_START_2PC)) { 
//    if(ret && (*responseType(m) == AWAIT_COMMIT_POINT && stateMachine->current_state==COORDINATOR_START_2PC)) {
	state_machine_id tmp = m->from_machine_id;
	m->from_machine_id = m->initiator_machine_id;
	//printf("Coordinator responding: ? ht=? (key length %d) %d ->   to %s:%ld\n",  getKeyLength(m), *(int*)getKeyAddr(m), /*getValAddr(m),*/ m->initiator, m->initiator_machine_id );
	respond_once(&((DfaSet*)dfaSet)->networkSetup, COORDINATOR_COMMITTING_2PC, m, m->initiator);
	m->from_machine_id = tmp;
    }
    return ret; 
  } else {
    sprintf(from, "bc:%d", bc_group);
  
    return FALSE;
  }
  
}