msgpass.c

clips源代码

   /*******************************************************/
   /*      "C" Language Integrated Production System      */
   /*                                                     */
   /*               CLIPS Version 6.24  05/17/06          */
   /*                                                     */
   /*              OBJECT MESSAGE DISPATCH CODE           */
   /*******************************************************/

/*************************************************************/
/* Purpose:                                                  */
/*                                                           */
/* Principal Programmer(s):                                  */
/*      Brian L. Donnell                                     */
/*                                                           */
/* Contributing Programmer(s):                               */
/*                                                           */
/* Revision History:                                         */
/*      6.23: Correction for FalseSymbol/TrueSymbol. DR0859  */
/*                                                           */
/*      6.24: Removed IMPERATIVE_MESSAGE_HANDLERS and        */
/*            AUXILIARY_MESSAGE_HANDLERS compilation flags.  */
/*                                                           */
/*            Renamed BOOLEAN macro type to intBool.         */
/*                                                           */
/*************************************************************/

/* =========================================
   *****************************************
               EXTERNAL DEFINITIONS
   =========================================
   ***************************************** */
#include "setup.h"

#if OBJECT_SYSTEM

#ifndef _STDIO_INCLUDED_
#include <stdio.h>
#define _STDIO_INCLUDED_
#endif
#include <stdlib.h>

#include "argacces.h"
#include "classcom.h"
#include "classfun.h"
#include "memalloc.h"
#include "constrct.h"
#include "envrnmnt.h"
#include "exprnpsr.h"
#include "insfun.h"
#include "msgcom.h"
#include "msgfun.h"
#include "multifld.h"
#include "prcdrfun.h"
#include "prccode.h"
#include "proflfun.h"
#include "router.h"
#include "strngfun.h"
#include "utility.h"
#include "commline.h"

#define _MSGPASS_SOURCE_
#include "msgpass.h"

#include "inscom.h"

/* =========================================
   *****************************************
      INTERNALLY VISIBLE FUNCTION HEADERS
   =========================================
   ***************************************** */

static void PerformMessage(void *,DATA_OBJECT *,EXPRESSION *,SYMBOL_HN *);
static HANDLER_LINK *FindApplicableHandlers(void *,DEFCLASS *,SYMBOL_HN *);
static void CallHandlers(void *,DATA_OBJECT *);
static void EarlySlotBindError(void *,INSTANCE_TYPE *,DEFCLASS *,unsigned);

/* =========================================
   *****************************************
          EXTERNALLY VISIBLE FUNCTIONS
   =========================================
   ***************************************** */

/*****************************************************
  NAME         : DirectMessage
  DESCRIPTION  : Plugs in given instance and
                  performs specified message
  INPUTS       : 1) Message symbolic name
                 2) The instance address
                 3) Address of DATA_OBJECT buffer
                    (NULL if don't care)
                 4) Message argument expressions
  RETURNS      : Nothing useful
  SIDE EFFECTS : Side effects of message execution
  NOTES        : None
 *****************************************************/
globle void DirectMessage(
  void *theEnv,
  SYMBOL_HN *msg,
  INSTANCE_TYPE *ins,
  DATA_OBJECT *resultbuf,
  EXPRESSION *remargs)
  {
   EXPRESSION args;
   DATA_OBJECT temp;

   if (resultbuf == NULL)
     resultbuf = &temp;
   args.nextArg = remargs;
   args.argList = NULL;
   args.type = INSTANCE_ADDRESS;
   args.value = (void *) ins;
   PerformMessage(theEnv,resultbuf,&args,msg);
  }

/***************************************************
  NAME         : EnvSend
  DESCRIPTION  : C Interface for sending messages to
                  instances
  INPUTS       : 1) The data object of the instance
                 2) The message name-string
                 3) The message arguments string
                    (Constants only)
                 4) Caller's buffer for result
  RETURNS      : Nothing useful
  SIDE EFFECTS : Executes message and stores result
                   caller's buffer
  NOTES        : None
 ***************************************************/
globle void EnvSend(
  void *theEnv,
  DATA_OBJECT *idata,
  char *msg,
  char *args,
  DATA_OBJECT *result)
  {
   int error;
   EXPRESSION *iexp;
   SYMBOL_HN *msym;

   if ((EvaluationData(theEnv)->CurrentEvaluationDepth == 0) && (! CommandLineData(theEnv)->EvaluatingTopLevelCommand) &&
       (EvaluationData(theEnv)->CurrentExpression == NULL))
     { PeriodicCleanup(theEnv,TRUE,FALSE); }

   SetEvaluationError(theEnv,FALSE);
   result->type = SYMBOL;
   result->value = EnvFalseSymbol(theEnv);
   msym = FindSymbolHN(theEnv,msg);
   if (msym == NULL)
     {
      PrintNoHandlerError(theEnv,msg);
      SetEvaluationError(theEnv,TRUE);
      return;
     }
   iexp = GenConstant(theEnv,idata->type,idata->value);
   iexp->nextArg = ParseConstantArguments(theEnv,args,&error);
   if (error == TRUE)
     {
      ReturnExpression(theEnv,iexp);
      SetEvaluationError(theEnv,TRUE);
      return;
     }
   PerformMessage(theEnv,result,iexp,msym);
   ReturnExpression(theEnv,iexp);
  }

/*****************************************************
  NAME         : DestroyHandlerLinks
  DESCRIPTION  : Iteratively deallocates handler-links
  INPUTS       : The handler-link list
  RETURNS      : Nothing useful
  SIDE EFFECTS : Deallocation of links
  NOTES        : None
 *****************************************************/
globle void DestroyHandlerLinks(
  void *theEnv,
  HANDLER_LINK *mhead)
  {
   HANDLER_LINK *tmp;

   while (mhead != NULL)
     {
      tmp = mhead;
      mhead = mhead->nxt;
      tmp->hnd->busy--;
      DecrementDefclassBusyCount(theEnv,(void *) tmp->hnd->cls);
      rtn_struct(theEnv,messageHandlerLink,tmp);
     }
  }

/***********************************************************************
  NAME         : SendCommand
  DESCRIPTION  : Determines the applicable handler(s) and sets up the
                   core calling frame.  Then calls the core frame.
  INPUTS       : Caller's space for storing the result of the handler(s)
  RETURNS      : Nothing useful
  SIDE EFFECTS : Any side-effects caused by the execution of handlers in
                   the core framework
  NOTES        : H/L Syntax : (send <instance> <hnd> <args>*)
 ***********************************************************************/
globle void SendCommand(
  void *theEnv,
  DATA_OBJECT *result)
  {
   EXPRESSION args;
   SYMBOL_HN *msg;
   DATA_OBJECT temp;

   result->type = SYMBOL;
   result->value = EnvFalseSymbol(theEnv);
   if (EnvArgTypeCheck(theEnv,"send",2,SYMBOL,&temp) == FALSE)
     return;
   msg = (SYMBOL_HN *) temp.value;

   /* =============================================
      Get the instance or primitive for the message
      ============================================= */
   args.type = GetFirstArgument()->type;
   args.value = GetFirstArgument()->value;
   args.argList = GetFirstArgument()->argList;
   args.nextArg = GetFirstArgument()->nextArg->nextArg;

   PerformMessage(theEnv,result,&args,msg);
  }

/***************************************************
  NAME         : GetNthMessageArgument
  DESCRIPTION  : Returns the address of the nth
                 (starting at 1) which is an
                 argument of the current message
                 dispatch
  INPUTS       : None
  RETURNS      : The message argument
  SIDE EFFECTS : None
  NOTES        : The active instance is always
                 stored as the first argument (0) in
                 the call frame of the message
 ***************************************************/
globle DATA_OBJECT *GetNthMessageArgument(
  void *theEnv,
  int n)
  {
   return(&ProceduralPrimitiveData(theEnv)->ProcParamArray[n]);
  }

/*****************************************************
  NAME         : NextHandlerAvailable
  DESCRIPTION  : Determines if there the currently
                   executing handler can call a
                   shadowed handler
                 Used before calling call-next-handler
  INPUTS       : None
  RETURNS      : TRUE if shadow ready, FALSE otherwise
  SIDE EFFECTS : None
  NOTES        : H/L Syntax: (next-handlerp)
 *****************************************************/
globle int NextHandlerAvailable(
  void *theEnv)
  {
   if (MessageHandlerData(theEnv)->CurrentCore == NULL)
     return(FALSE);
   if (MessageHandlerData(theEnv)->CurrentCore->hnd->type == MAROUND)
     return((MessageHandlerData(theEnv)->NextInCore != NULL) ? TRUE : FALSE);
   if ((MessageHandlerData(theEnv)->CurrentCore->hnd->type == MPRIMARY) && (MessageHandlerData(theEnv)->NextInCore != NULL))
     return((MessageHandlerData(theEnv)->NextInCore->hnd->type == MPRIMARY) ? TRUE : FALSE);
   return(FALSE);
  }

/********************************************************
  NAME         : CallNextHandler
  DESCRIPTION  : This function allows around-handlers
                   to execute the rest of the core frame.
                 It also allows primary handlers
                   to execute shadowed primaries.

                 The original handler arguments are
                   left intact.
  INPUTS       : The caller's result-value buffer
  RETURNS      : Nothing useful
  SIDE EFFECTS : The core frame is called and any
                   appropriate changes are made when
                   used in an around handler
                   See CallHandlers()
                 But when call-next-handler is called
                   from a primary, the same shadowed
                   primary is called over and over
                   again for repeated calls to
                   call-next-handler.
  NOTES        : H/L Syntax: (call-next-handler) OR
                    (override-next-handler <arg> ...)
 ********************************************************/
globle void CallNextHandler(
  void *theEnv,
  DATA_OBJECT *result)
  {
   EXPRESSION args;
   int overridep;
   HANDLER_LINK *oldNext,*oldCurrent;
#if PROFILING_FUNCTIONS
   struct profileFrameInfo profileFrame;
#endif

   SetpType(result,SYMBOL);
   SetpValue(result,EnvFalseSymbol(theEnv));
   EvaluationData(theEnv)->EvaluationError = FALSE;
   if (EvaluationData(theEnv)->HaltExecution)
     return;
   if (NextHandlerAvailable(theEnv) == FALSE)
     {
      PrintErrorID(theEnv,"MSGPASS",1,FALSE);
      EnvPrintRouter(theEnv,WERROR,"Shadowed message-handlers not applicable in current context.\n");
      SetEvaluationError(theEnv,TRUE);
      return;
     }
   if (EvaluationData(theEnv)->CurrentExpression->value == (void *) FindFunction(theEnv,"override-next-handler"))
     {
      overridep = 1;
      args.type = ProceduralPrimitiveData(theEnv)->ProcParamArray[0].type;
      if (args.type != MULTIFIELD)
        args.value = (void *) ProceduralPrimitiveData(theEnv)->ProcParamArray[0].value;
      else
        args.value = (void *) &ProceduralPrimitiveData(theEnv)->ProcParamArray[0];
      args.nextArg = GetFirstArgument();
      args.argList = NULL;
      PushProcParameters(theEnv,&args,CountArguments(&args),
                          ValueToString(MessageHandlerData(theEnv)->CurrentMessageName),"message",
                          UnboundHandlerErr);
      if (EvaluationData(theEnv)->EvaluationError)
        {
         ProcedureFunctionData(theEnv)->ReturnFlag = FALSE;
         return;
        }
     }
   else
     overridep = 0;
   oldNext = MessageHandlerData(theEnv)->NextInCore;
   oldCurrent = MessageHandlerData(theEnv)->CurrentCore;
   if (MessageHandlerData(theEnv)->CurrentCore->hnd->type == MAROUND)
     {
      if (MessageHandlerData(theEnv)->NextInCore->hnd->type == MAROUND)
        {
         MessageHandlerData(theEnv)->CurrentCore = MessageHandlerData(theEnv)->NextInCore;
         MessageHandlerData(theEnv)->NextInCore = MessageHandlerData(theEnv)->NextInCore->nxt;
#if DEBUGGING_FUNCTIONS
         if (MessageHandlerData(theEnv)->CurrentCore->hnd->trace)