path: root/contrib/tools/swig/Source/Modules/emit.cxx

/* -----------------------------------------------------------------------------
 * This file is part of SWIG, which is licensed as a whole under version 3 
 * (or any later version) of the GNU General Public License. Some additional
 * terms also apply to certain portions of SWIG. The full details of the SWIG
 * license and copyrights can be found in the LICENSE and COPYRIGHT files
 * included with the SWIG source code as distributed by the SWIG developers
 * and at https://www.swig.org/legal.html.
 *
 * emit.cxx
 *
 * Useful functions for emitting various pieces of code.
 * ----------------------------------------------------------------------------- */

#include "swigmod.h"
#include "cparse.h"

/* -----------------------------------------------------------------------------
 * emit_return_variable()
 *
 * Emits a variable declaration for a function return value.
 * The variable name is always called result.
 * n => Node of the method being wrapped
 * rt => the return type
 * f => the wrapper to generate code into
 * ----------------------------------------------------------------------------- */

void emit_return_variable(Node *n, SwigType *rt, Wrapper *f) {

  if (!GetFlag(n, "tmap:out:optimal")) {
    if (rt && (SwigType_type(rt) != T_VOID)) {
      SwigType *vt = cplus_value_type(rt);
      SwigType *tt = vt ? vt : rt;
      SwigType *lt = SwigType_ltype(tt);
      String *lstr = SwigType_str(lt, Swig_cresult_name());
      if (SwigType_ispointer(lt)) {
        Wrapper_add_localv(f, Swig_cresult_name(), lstr, "= 0", NULL);
      } else {
        Wrapper_add_local(f, Swig_cresult_name(), lstr);
      }
      if (vt) {
        Delete(vt);
      }
      Delete(lt);
      Delete(lstr);
    }
  }
}

/* -----------------------------------------------------------------------------
 * emit_parameter_variables()
 *
 * Emits a list of variable declarations for function parameters.
 * The variable names are always called arg1, arg2, etc...
 * l => the parameter list
 * f => the wrapper to generate code into
 * ----------------------------------------------------------------------------- */

void emit_parameter_variables(ParmList *l, Wrapper *f) {

  Parm *p;
  String *tm;

  /* Emit function arguments */
  Swig_cargs(f, l);

  /* Attach typemaps to parameters */
  /*  Swig_typemap_attach_parms("ignore",l,f); */

  Swig_typemap_attach_parms("default", l, f);
  Swig_typemap_attach_parms("arginit", l, f);

  /* Apply the arginit and default */
  p = l;
  while (p) {
    tm = Getattr(p, "tmap:arginit");
    if (tm) {
      Printv(f->code, tm, "\n", NIL);
      p = Getattr(p, "tmap:arginit:next");
    } else {
      p = nextSibling(p);
    }
  }

  /* Apply the default typemap */
  p = l;
  while (p) {
    tm = Getattr(p, "tmap:default");
    if (tm) {
      Printv(f->code, tm, "\n", NIL);
      p = Getattr(p, "tmap:default:next");
    } else {
      p = nextSibling(p);
    }
  }
}

/* -----------------------------------------------------------------------------
 * emit_attach_parmmaps()
 *
 * Attach the standard parameter related typemaps.
 * ----------------------------------------------------------------------------- */

void emit_attach_parmmaps(ParmList *l, Wrapper *f) {
  Swig_typemap_attach_parms("in", l, f);
  Swig_typemap_attach_parms("typecheck", l, 0);
  Swig_typemap_attach_parms("argout", l, f);
  Swig_typemap_attach_parms("check", l, f);
  Swig_typemap_attach_parms("freearg", l, f);

  {
    /* This is compatibility code to deal with the deprecated "ignore" typemap */
    Parm *p = l;
    Parm *np;
    while (p) {
      String *tm = Getattr(p, "tmap:in");
      if (tm && checkAttribute(p, "tmap:in:numinputs", "0")) {
	Printv(f->code, tm, "\n", NIL);
	np = Getattr(p, "tmap:in:next");
	while (p && (p != np)) {
	  /*	  Setattr(p,"ignore","1");    Deprecate */
	  p = nextSibling(p);
	}
      } else if (tm) {
	p = Getattr(p, "tmap:in:next");
      } else {
	p = nextSibling(p);
      }
    }
  }

  /* Perform a sanity check on "in" and "freearg" typemaps.  These
     must exactly match to avoid chaos.  If a mismatch occurs, we
     nuke the freearg typemap */
  {
    Parm *p = l;
    Parm *npin, *npfreearg;
    while (p) {
      npin = Getattr(p, "tmap:in:next");

      /*
         if (Getattr(p,"tmap:ignore")) {
         npin = Getattr(p,"tmap:ignore:next");
         } else if (Getattr(p,"tmap:in")) {
         npin = Getattr(p,"tmap:in:next");
         }
       */

      if (Getattr(p, "tmap:freearg")) {
	npfreearg = Getattr(p, "tmap:freearg:next");
	if (npin != npfreearg) {
	  while (p != npin) {
	    Delattr(p, "tmap:freearg");
	    Delattr(p, "tmap:freearg:next");
	    p = nextSibling(p);
	  }
	}
      }
      p = npin;
    }
  }

  /* Check for variable length arguments with no input typemap.
     If no input is defined, we set this to ignore and print a
     message.
   */
  {
    Parm *p = l;
    Parm *lp = 0;
    while (p) {
      if (!checkAttribute(p, "tmap:in:numinputs", "0")) {
	lp = p;
	p = Getattr(p, "tmap:in:next");
	continue;
      }
      if (SwigType_isvarargs(Getattr(p, "type"))) {
	Swig_warning(WARN_LANG_VARARGS, input_file, line_number, "Variable length arguments discarded.\n");
	Setattr(p, "tmap:in", "");
      }
      lp = 0;
      p = nextSibling(p);
    }

    /* Check if last input argument is variable length argument */
    if (lp) {
      p = lp;
      while (p) {
	if (SwigType_isvarargs(Getattr(p, "type"))) {
	  // Mark the head of the ParmList that it has varargs
	  Setattr(l, "emit:varargs", lp);
//Printf(stdout, "setting emit:varargs %s ... %s +++ %s\n", Getattr(l, "emit:varargs"), Getattr(l, "type"), Getattr(p, "type"));
	  break;
	}
	p = nextSibling(p);
      }
    }
  }

  /* 
   * An equivalent type can be used in the typecheck typemap for SWIG to detect the overloading of equivalent
   * target language types. This is primarily for the smartptr feature, where a pointer and a smart pointer
   * are seen as equivalent types in the target language.
   */
  {
    Parm *p = l;
    while (p) {
      String *tm = Getattr(p, "tmap:typecheck");
      if (tm) {
	String *equivalent = Getattr(p, "tmap:typecheck:equivalent");
	if (equivalent) {
	  String *precedence = Getattr(p, "tmap:typecheck:precedence");
	  if (precedence && Strcmp(precedence, "0") != 0)
	    Swig_error(Getfile(tm), Getline(tm), "The 'typecheck' typemap for %s contains an 'equivalent' attribute for a 'precedence' that is not set to SWIG_TYPECHECK_POINTER or 0.\n", SwigType_str(Getattr(p, "type"), 0));
	  SwigType *cpt = Swig_cparse_type(equivalent);
	  if (cpt) {
	    Setattr(p, "equivtype", cpt);
	    Delete(cpt);
	  } else {
	    Swig_error(Getfile(tm), Getline(tm), "Invalid type (%s) in 'equivalent' attribute in 'typecheck' typemap for type %s.\n", equivalent, SwigType_str(Getattr(p, "type"), 0));
	  }
	}
	p = Getattr(p, "tmap:typecheck:next");
      } else {
	p = nextSibling(p);
      }
    }
  }
}

/* -----------------------------------------------------------------------------
 * emit_num_arguments()
 *
 * Calculate the total number of arguments.   This function is safe for use
 * with multi-argument typemaps which may change the number of arguments in
 * strange ways.
 * ----------------------------------------------------------------------------- */

int emit_num_arguments(ParmList *parms) {
  Parm *p = parms;
  int nargs = 0;

  while (p) {
    if (Getattr(p, "tmap:in")) {
      nargs += GetInt(p, "tmap:in:numinputs");
      p = Getattr(p, "tmap:in:next");
    } else {
      p = nextSibling(p);
    }
  }

  /* DB 04/02/2003: Not sure this is necessary with tmap:in:numinputs */
  /*
     if (parms && (p = Getattr(parms,"emit:varargs"))) {
     if (!nextSibling(p)) {
     nargs--;
     }
     }
   */
  return nargs;
}

/* -----------------------------------------------------------------------------
 * emit_num_required()
 *
 * Computes the number of required arguments.  This function is safe for
 * use with multi-argument typemaps and knows how to skip over everything
 * properly. Note that parameters with default values are counted unless
 * the compact default args option is on.
 * ----------------------------------------------------------------------------- */

int emit_num_required(ParmList *parms) {
  Parm *p = parms;
  int nargs = 0;
  Parm *first_default_arg = 0;
  int compactdefargs = ParmList_is_compactdefargs(p);

  while (p) {
    if (Getattr(p, "tmap:in") && checkAttribute(p, "tmap:in:numinputs", "0")) {
      p = Getattr(p, "tmap:in:next");
    } else {
      if (Getattr(p, "tmap:default"))
	break;
      if (Getattr(p, "value")) {
	if (!first_default_arg)
	  first_default_arg = p;
	if (compactdefargs)
	  break;
      }
      nargs += GetInt(p, "tmap:in:numinputs");
      if (Getattr(p, "tmap:in")) {
	p = Getattr(p, "tmap:in:next");
      } else {
	p = nextSibling(p);
      }
    }
  }

  /* Print error message for non-default arguments following default arguments */
  /* The error message is printed more than once with most language modules, this ought to be fixed */
  if (first_default_arg) {
    p = first_default_arg;
    while (p) {
      if (Getattr(p, "tmap:in") && checkAttribute(p, "tmap:in:numinputs", "0")) {
	p = Getattr(p, "tmap:in:next");
      } else {
	if (!Getattr(p, "value") && (!Getattr(p, "tmap:default"))) {
	  Swig_error(Getfile(p), Getline(p), "Non-optional argument '%s' follows an optional argument.\n", Getattr(p, "name"));
	}
	if (Getattr(p, "tmap:in")) {
	  p = Getattr(p, "tmap:in:next");
	} else {
	  p = nextSibling(p);
	}
      }
    }
  }

  /* DB 04/02/2003: Not sure this is necessary with tmap:in:numinputs */
  /*
     if (parms && (p = Getattr(parms,"emit:varargs"))) {
     if (!nextSibling(p)) {
     nargs--;
     }
     }
   */
  return nargs;
}

/* -----------------------------------------------------------------------------
 * emit_isvarargs()
 *
 * Checks if a ParmList is a parameter list containing varargs.
 * This function requires emit_attach_parmmaps to have been called beforehand.
 * ----------------------------------------------------------------------------- */

int emit_isvarargs(ParmList *p) {
  if (!p)
    return 0;
  if (Getattr(p, "emit:varargs"))
    return 1;
  return 0;
}

/* -----------------------------------------------------------------------------
 * emit_isvarargs_function()
 *
 * Checks for varargs in a function/constructor (can be overloaded)
 * ----------------------------------------------------------------------------- */

bool emit_isvarargs_function(Node *n) {
  bool has_varargs = false;
  Node *over = Getattr(n, "sym:overloaded");
  if (over) {
    for (Node *sibling = over; sibling; sibling = Getattr(sibling, "sym:nextSibling")) {
      if (ParmList_has_varargs(Getattr(sibling, "parms"))) {
	has_varargs = true;
	break;
      }
    }
  } else {
    has_varargs = ParmList_has_varargs(Getattr(n, "parms")) ? true : false;
  }
  return has_varargs;
}

/* -----------------------------------------------------------------------------
 * void emit_mark_vararg_parms()
 *
 * Marks the vararg parameters which are to be ignored.
 * Vararg parameters are marked as ignored if there is no 'in' varargs (...) 
 * typemap.
 * ----------------------------------------------------------------------------- */

void emit_mark_varargs(ParmList *l) {
  Parm *p = l;
  while (p) {
    if (SwigType_isvarargs(Getattr(p, "type")))
      if (!Getattr(p, "tmap:in"))
	Setattr(p, "varargs:ignore", "1");
    p = nextSibling(p);
  }
}

#if 0
/* replace_contract_args.  This function replaces argument names in contract
   specifications.   Used in conjunction with the %contract directive. */

static void replace_contract_args(Parm *cp, Parm *rp, String *s) {
  while (cp && rp) {
    String *n = Getattr(cp, "name");
    if (n) {
      Replace(s, n, Getattr(rp, "lname"), DOH_REPLACE_ID);
    }
    cp = nextSibling(cp);
    rp = nextSibling(rp);
  }
}
#endif

/* -----------------------------------------------------------------------------
 * int emit_action_code()
 *
 * Emits action code for a wrapper. Adds in exception handling code (%exception).
 * eaction -> the action code to emit
 * wrappercode -> the emitted code (output)
 * ----------------------------------------------------------------------------- */
int emit_action_code(Node *n, String *wrappercode, String *eaction) {
  assert(Getattr(n, "wrap:name"));

  /* Look for except feature (%exception) */
  String *tm = GetFlagAttr(n, "feature:except");
  if (tm)
    tm = Copy(tm);
  if ((tm) && Len(tm) && (Strcmp(tm, "1") != 0)) {
    if (Strstr(tm, "$")) {
      Swig_replace_special_variables(n, parentNode(n), tm);
      Replaceall(tm, "$function", eaction); // deprecated
      Replaceall(tm, "$action", eaction);
    }
    Printv(wrappercode, tm, "\n", NIL);
    Delete(tm);
    return 1;
  } else {
    Printv(wrappercode, eaction, "\n", NIL);
    return 0;
  }
}

/* -----------------------------------------------------------------------------
 * int emit_action()
 *
 * Emits the call to the wrapped function. 
 * Adds in exception specification exception handling and %exception code.
 * ----------------------------------------------------------------------------- */
String *emit_action(Node *n) {
  String *actioncode = NewStringEmpty();
  String *tm;
  String *action;
  String *wrap;
  ParmList *catchlist = Getattr(n, "catchlist");

  /* Look for fragments */
  {
    String *fragment = Getattr(n, "feature:fragment");
    if (fragment) {
      char *c, *tok;
      String *t = Copy(fragment);
      c = Char(t);
      tok = strtok(c, ",");
      while (tok) {
	String *fname = NewString(tok);
	Setfile(fname, Getfile(n));
	Setline(fname, Getline(n));
	Swig_fragment_emit(fname);
	Delete(fname);
	tok = strtok(NULL, ",");
      }
      Delete(t);
    }
  }

  /* Emit wrapper code (if any) */
  wrap = Getattr(n, "wrap:code");
  if (wrap && Swig_filebyname("header") != Getattr(n, "wrap:code:done")) {
    File *f_code = Swig_filebyname("header");
    if (f_code) {
      Printv(f_code, wrap, NIL);
    }
    Setattr(n, "wrap:code:done", f_code);
  }

  action = Getattr(n, "feature:action");
  if (!action)
    action = Getattr(n, "wrap:action");
  assert(action != 0);

  /* Emit contract code (if any) */
  if (Swig_contract_mode_get()) {
    /* Preassertion */
    tm = Getattr(n, "contract:preassert");
    if (Len(tm)) {
      Printv(actioncode, tm, "\n", NIL);
    }
  }
  /* Exception handling code */

  /* saves action -> eaction for postcatching exception */
  String *eaction = NewString("");

  /* If we are in C++ mode and there is an exception specification. We're going to
     enclose the block in a try block */
  if (catchlist) {
    Printf(eaction, "try {\n");
  }

  String *preaction = Getattr(n, "wrap:preaction");
  if (preaction)
    Printv(eaction, preaction, NIL);

  Printv(eaction, action, NIL);

  String *postaction = Getattr(n, "wrap:postaction");
  if (postaction)
    Printv(eaction, postaction, NIL);

  if (catchlist) {
    int unknown_catch = 0;
    int has_varargs = 0;
    Printf(eaction, "}");
    for (Parm *ep = catchlist; ep; ep = nextSibling(ep)) {
      String *em = Swig_typemap_lookup("throws", ep, "_e", 0);
      if (em) {
        SwigType *et = Getattr(ep, "type");
        SwigType *etr = SwigType_typedef_resolve_all(et);
        if (SwigType_isreference(etr) || SwigType_ispointer(etr) || SwigType_isarray(etr)) {
          Printf(eaction, " catch(%s) {", SwigType_str(et, "_e"));
        } else if (SwigType_isvarargs(etr)) {
          Printf(eaction, " catch(...) {");
          has_varargs = 1;
        } else {
          Printf(eaction, " catch(%s) {", SwigType_str(et, "&_e"));
        }
        Printv(eaction, em, "\n", NIL);
        Printf(eaction, "}");
      } else {
	Swig_warning(WARN_TYPEMAP_THROW, Getfile(n), Getline(n), "No 'throws' typemap defined for exception type '%s'\n", SwigType_str(Getattr(ep, "type"), 0));
        unknown_catch = 1;
      }
    }
    if (unknown_catch && !has_varargs) {
      Printf(eaction, " catch(...) {\nthrow;\n}");
    }
  }

  /* Look for except typemap (Deprecated) */
  tm = Swig_typemap_lookup("except", n, Swig_cresult_name(), 0);
  if (tm) {
    Setattr(n, "feature:except", tm);
    tm = 0;
  }

  /* emit the except feature code */
  emit_action_code(n, actioncode, eaction);

  Delete(eaction);

  /* Emit contract code (if any) */
  if (Swig_contract_mode_get()) {
    /* Postassertion */
    tm = Getattr(n, "contract:postassert");
    if (Len(tm)) {
      Printv(actioncode, tm, "\n", NIL);
    }
  }

  return actioncode;
}