---

dtool/src/interrogate/interfaceMaker.cxx

Go to the documentation of this file.

// Filename: interfaceMaker.cxx
// Created by:  drose (19Sep01)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001, Disney Enterprises, Inc.  All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license.  You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://www.panda3d.org/license.txt .
//
// To contact the maintainers of this program write to
// panda3d@yahoogroups.com .
//
////////////////////////////////////////////////////////////////////

#include "interfaceMaker.h"
#include "interrogateBuilder.h"
#include "typeManager.h"
#include "interrogate.h"
#include "functionRemap.h"
#include "parameterRemap.h"
#include "parameterRemapThis.h"
#include "parameterRemapUnchanged.h"
#include "parameterRemapReferenceToPointer.h"
#include "parameterRemapConcreteToPointer.h"
#include "parameterRemapEnumToInt.h"
#include "parameterRemapConstToNonConst.h"
#include "parameterRemapReferenceToConcrete.h"
#include "parameterRemapCharStarToString.h"
#include "parameterRemapBasicStringToString.h"
#include "parameterRemapBasicStringRefToString.h"
#include "parameterRemapPTToPointer.h"

#include "interrogateDatabase.h"
#include "interrogateManifest.h"
#include "interrogateElement.h"
#include "cppFunctionType.h"
#include "cppParameterList.h"
#include "notify.h"

static InterrogateType dummy_type;

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::Function::Constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
InterfaceMaker::Function::
Function(const string &name,
         const InterrogateType &itype,
         const InterrogateFunction &ifunc) :
  _name(name),
  _itype(itype),
  _ifunc(ifunc)
{
  _has_this = false;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::Function::Destructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
InterfaceMaker::Function::
~Function() {
  Remaps::iterator ri;
  for (ri = _remaps.begin(); ri != _remaps.end(); ++ri) {
    delete (*ri);
  }
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::Object::Constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
InterfaceMaker::Object::
Object(const InterrogateType &itype) :
  _itype(itype)
{
  _destructor = (Function *)NULL;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::Object::Destructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
InterfaceMaker::Object::
~Object() {
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::Constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
InterfaceMaker::
InterfaceMaker(InterrogateModuleDef *def) :
  _def(def)
{
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::Destructor
//       Access: Public, Virtual
//  Description:
////////////////////////////////////////////////////////////////////
InterfaceMaker::
~InterfaceMaker() {
  Objects::iterator oi;
  for (oi = _objects.begin(); oi != _objects.end(); ++oi) {
    Object *object = (*oi).second;
    delete object;
  }
  Functions::iterator fi;
  for (fi = _functions.begin(); fi != _functions.end(); ++fi) {
    delete (*fi);
  }
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::generate_wrappers
//       Access: Public, Virtual
//  Description: Walks through the set of functions in the database
//               and generates wrappers for each function, storing
//               these in the database.  No actual code should be
//               output yet; this just updates the database with the
//               wrapper information.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
generate_wrappers() {
  InterrogateDatabase *idb = InterrogateDatabase::get_ptr();

  // We use a while loop rather than a simple for loop, because we
  // might increase the number of types recursively during the
  // traversal.
  int ti = 0;
  while (ti < idb->get_num_all_types()) {
    TypeIndex type_index = idb->get_all_type(ti);
    record_object(type_index);
    ++ti;
  }

  int num_functions = idb->get_num_global_functions();
  for (int fi = 0; fi < num_functions; fi++) {
    FunctionIndex func_index = idb->get_global_function(fi);
    record_function(dummy_type, func_index);
  }    

  int num_manifests = idb->get_num_global_manifests();
  for (int mi = 0; mi < num_manifests; mi++) {
    ManifestIndex manifest_index = idb->get_global_manifest(mi);
    const InterrogateManifest &iman = idb->get_manifest(manifest_index);
    if (iman.has_getter()) {
      FunctionIndex func_index = iman.get_getter();
      record_function(dummy_type, func_index);
    }
  }    

  int num_elements = idb->get_num_global_elements();
  for (int ei = 0; ei < num_elements; ei++) {
    ElementIndex element_index = idb->get_global_element(ei);
    const InterrogateElement &ielement = idb->get_element(element_index);
    if (ielement.has_getter()) {
      FunctionIndex func_index = ielement.get_getter();
      record_function(dummy_type, func_index);
    }
    if (ielement.has_setter()) {
      FunctionIndex func_index = ielement.get_setter();
      record_function(dummy_type, func_index);
    }
  }    
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::write_includes
//       Access: Public, Virtual
//  Description: Generates the list of #include ... whatever that's
//               required by this particular interface to the
//               indicated output stream.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
write_includes(ostream &) {
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::write_prototypes
//       Access: Public, Virtual
//  Description: Generates the list of function prototypes
//               corresponding to the functions that will be output in
//               write_functions().
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
write_prototypes(ostream &out) {
  _function_writers.write_prototypes(out);
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::write_functions
//       Access: Public, Virtual
//  Description: Generates the list of functions that are appropriate
//               for this interface.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
write_functions(ostream &out) {
  _function_writers.write_code(out);
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::write_module
//       Access: Public, Virtual
//  Description: Generates whatever additional code is required to
//               support a module file.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
write_module(ostream &, InterrogateModuleDef *) {
}


////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::remap_parameter
//       Access: Public, Virtual
//  Description: Allocates a new ParameterRemap object suitable to the
//               indicated parameter type.  If struct_type is
//               non-NULL, it is the type of the enclosing class for
//               the function (method) in question.
//
//               The return value is a newly-allocated ParameterRemap
//               object, if the parameter type is acceptable, or NULL
//               if the parameter type cannot be handled.
////////////////////////////////////////////////////////////////////
ParameterRemap *InterfaceMaker::
remap_parameter(CPPType *struct_type, CPPType *param_type) {
  if (convert_strings) {
    if (TypeManager::is_char_pointer(param_type)) {
      return new ParameterRemapCharStarToString(param_type);
    }

    // If we're exporting a method of basic_string<char> itself, don't
    // convert basic_string<char>'s to atomic strings.

    if (struct_type == (CPPType *)NULL ||
        !TypeManager::is_basic_string_char(struct_type)) {
      if (TypeManager::is_basic_string_char(param_type)) {
        return new ParameterRemapBasicStringToString(param_type);

      } else if (TypeManager::is_const_ref_to_basic_string_char(param_type)) {
        return new ParameterRemapBasicStringRefToString(param_type);
      }
    }
  }

  if (manage_reference_counts) {
    if (TypeManager::is_pointer_to_base(param_type) ||
        TypeManager::is_const_ref_to_pointer_to_base(param_type)) {
      CPPType *pt_type = TypeManager::unwrap_reference(param_type);

      // Don't convert PointerTo<>'s to pointers for methods of the
      // PointerTo itself!
      if (struct_type == (CPPType *)NULL ||
          !(pt_type->get_local_name(&parser) == struct_type->get_local_name(&parser))) {
        return new ParameterRemapPTToPointer(param_type);
      }
    }
  }

  if (TypeManager::is_reference(param_type)) {
    return new ParameterRemapReferenceToPointer(param_type);

  } else if (TypeManager::is_struct(param_type)) {
    return new ParameterRemapConcreteToPointer(param_type);

    /*
  } else if (TypeManager::is_enum(param_type) || TypeManager::is_const_ref_to_enum(param_type)) {
    return new ParameterRemapEnumToInt(param_type);
    */

  } else if (TypeManager::is_const_simple(param_type)) {
    return new ParameterRemapConstToNonConst(param_type);

  } else if (TypeManager::is_const_ref_to_simple(param_type)) {
    return new ParameterRemapReferenceToConcrete(param_type);

  } else if (TypeManager::is_pointer(param_type) || TypeManager::is_simple(param_type)) {
    return new ParameterRemapUnchanged(param_type);

  } else {
    // Here's something we have a problem with.
    return (ParameterRemap *)NULL;
  }
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::synthesize_this_parameter
//       Access: Public, Virtual
//  Description: This method should be overridden and redefined to
//               return true for interfaces that require the implicit
//               "this" parameter, if present, to be passed as the
//               first parameter to any wrapper functions.
////////////////////////////////////////////////////////////////////
bool InterfaceMaker::
synthesize_this_parameter() {
  return false;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::separate_overloading
//       Access: Public, Virtual
//  Description: This method should be overridden and redefined to
//               return true for interfaces that require overloaded
//               instances of a function to be defined as separate
//               functions (each with its own hashed name), or false
//               for interfaces that can support overloading natively,
//               and thus only require one wrapper function per each
//               overloaded input function.
////////////////////////////////////////////////////////////////////
bool InterfaceMaker::
separate_overloading() {
  return true;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::get_function_remaps
//       Access: Public
//  Description: Fills up the indicated vector with all of the
//               FunctionRemap pointers created by this
//               InterfaceMaker.  It is the user's responsibility to
//               empty the vector before calling this function; the
//               new pointers will simply be added to the end.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
get_function_remaps(vector<FunctionRemap *> &remaps) {
  Functions::iterator fi;
  for (fi = _functions.begin(); fi != _functions.end(); ++fi) {
    Function *func = (*fi);
    Function::Remaps::const_iterator ri;
    for (ri = func->_remaps.begin(); ri != func->_remaps.end(); ++ri) {
      FunctionRemap *remap = (*ri);
      remaps.push_back(remap);
    }
  }
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::indent
//       Access: Public, Static
//  Description:
////////////////////////////////////////////////////////////////////
ostream &InterfaceMaker::
indent(ostream &out, int indent_level) {
  for (int i = 0; i < indent_level; i++) {
    out << ' ';
  }
  return out;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::make_function_remap
//       Access: Protected, Virtual
//  Description: Creates a FunctionRemap object corresponding to the
//               particular function wrapper.
////////////////////////////////////////////////////////////////////
FunctionRemap *InterfaceMaker::
make_function_remap(const InterrogateType &itype,
                    const InterrogateFunction &ifunc,
                    CPPInstance *cppfunc, int num_default_parameters) {
  FunctionRemap *remap = 
    new FunctionRemap(itype, ifunc, cppfunc, num_default_parameters, this);
  if (remap->_is_valid) {
    if (separate_overloading()) {
      hash_function_signature(remap);
      remap->_unique_name =
        get_unique_prefix() + _def->library_hash_name + remap->_hash;
      remap->_wrapper_name = 
        get_wrapper_prefix() + _def->library_hash_name + remap->_hash;
    }
    return remap;
  }

  // No such FunctionRemap is valid.  Return NULL.
  delete remap;
  return (FunctionRemap *)NULL;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::get_wrapper_name
//       Access: Protected, Virtual
//  Description: Returns the function name that will be used to wrap
//               the indicated function.
//
//               This is the name for the overall wrapper function,
//               including all of the overloaded instances.
//               Interfaces that must define a different wrapper for
//               each FunctionRemap object (i.e. for each instance of
//               an overloaded function) need not define a name here.
////////////////////////////////////////////////////////////////////
string InterfaceMaker::
get_wrapper_name(const InterrogateType &itype, 
                 const InterrogateFunction &ifunc,
                 FunctionIndex func_index) {
  string func_name = ifunc.get_scoped_name();
  string clean_name = InterrogateBuilder::clean_identifier(func_name);

  ostringstream new_name;
  new_name << get_wrapper_prefix() << clean_name << "_" << func_index;
  return new_name.str();
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::get_wrapper_prefix
//       Access: Protected, Virtual
//  Description: Returns the prefix string used to generate wrapper
//               function names.
////////////////////////////////////////////////////////////////////
string InterfaceMaker::
get_wrapper_prefix() {
  return "xx_";
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::get_unique_prefix
//       Access: Protected, Virtual
//  Description: Returns the prefix string used to generate unique
//               symbolic names, which are not necessarily C-callable
//               function names.
////////////////////////////////////////////////////////////////////
string InterfaceMaker::
get_unique_prefix() {
  return "x";
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::record_function
//       Access: Protected
//  Description: Records the indicated function, along with all of its
//               FunctionRemap flavors and FunctionWriter helpers, for
//               future output.  Returns the new Function pointer.
////////////////////////////////////////////////////////////////////
InterfaceMaker::Function *InterfaceMaker::
record_function(const InterrogateType &itype, FunctionIndex func_index) {
  InterrogateDatabase *idb = InterrogateDatabase::get_ptr();
  const InterrogateFunction &ifunc = idb->get_function(func_index);

  string wrapper_name = get_wrapper_name(itype, ifunc, func_index);
  Function *func = new Function(wrapper_name, itype, ifunc);
  _functions.push_back(func);

  // Now get all the valid FunctionRemaps for the function.
  if (ifunc._instances != (InterrogateFunction::Instances *)NULL) {
    InterrogateFunction::Instances::const_iterator ii;
    for (ii = ifunc._instances->begin();
         ii != ifunc._instances->end();
         ++ii) {
      CPPInstance *cppfunc = (*ii).second;
      CPPFunctionType *ftype = cppfunc->_type->as_function_type();
      int max_default_parameters = 0;
      
      if (separate_overloading()) {
        // Count up the number of default parameters this function might
        // take.
        CPPParameterList *parameters = ftype->_parameters;
        CPPParameterList::Parameters::reverse_iterator pi;
        for (pi = parameters->_parameters.rbegin(); 
             pi != parameters->_parameters.rend();
             ++pi) {
          CPPInstance *param = (*pi);
          if (param->_initializer != (CPPExpression *)NULL) {
            // This parameter has a default value.
            max_default_parameters++;
          } else {
            // The first parameter without a default value ends the search.
            break;
          }
        }
      }
      
      // Now make a different wrapper for each combination of default
      // parameters.  This will happen only if separate_overloading(),
      // tested above, returned true; otherwise, max_default_parameters
      // will be 0 and the loop will only be traversed once.
      for (int num_default_parameters = 0; 
           num_default_parameters <= max_default_parameters;
           num_default_parameters++) {
        FunctionRemap *remap = 
          make_function_remap(itype, ifunc, cppfunc, num_default_parameters);
        if (remap != (FunctionRemap *)NULL) {
          func->_remaps.push_back(remap);
          
          // If *any* of the variants of this function has a "this"
          // pointer, the entire set of functions is deemed to have a
          // "this" pointer.
          if (remap->_has_this) {
            func->_has_this = true;
          }
          
          // Make a wrapper for the function.
          FunctionWrapperIndex wrapper_index = 
            remap->make_wrapper_entry(func_index);
          if (wrapper_index != 0) {
            InterrogateFunction &mod_ifunc = idb->update_function(func_index);
            record_function_wrapper(mod_ifunc, wrapper_index);
          }
        }
      }
    }
  }

  return func;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::record_function_wrapper
//       Access: Protected, Virtual
//  Description: Associates the function wrapper with its function in
//               the appropriate structures in the database.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
record_function_wrapper(InterrogateFunction &, FunctionWrapperIndex) {
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::record_object
//       Access: Protected
//  Description: Records the indicated type, which may be a struct
//               type, along with all of its associated methods, if
//               any.
////////////////////////////////////////////////////////////////////
InterfaceMaker::Object *InterfaceMaker::
record_object(TypeIndex type_index) {
  if (type_index == 0) {
    // An invalid type.
    return (Object *)NULL;
  }

  Objects::iterator oi = _objects.find(type_index);
  if (oi != _objects.end()) {
    // The object has previously been recorded.
    return (*oi).second;
  }

  InterrogateDatabase *idb = InterrogateDatabase::get_ptr();
  const InterrogateType &itype = idb->get_type(type_index);    

  Object *object = new Object(itype);
  bool inserted = _objects.insert(Objects::value_type(type_index, object)).second;
  assert(inserted);

  Function *function;

  int num_constructors = itype.number_of_constructors();
  for (int ci = 0; ci < num_constructors; ci++) {
    function = record_function(itype, itype.get_constructor(ci));
    object->_constructors.push_back(function);
  }

  if (itype.has_destructor() && !itype.destructor_is_inherited()) {
    function = record_function(itype, itype.get_destructor());
    object->_destructor = function;
  }
  
  int num_methods = itype.number_of_methods();
  int mi;
  for (mi = 0; mi < num_methods; mi++) {
    function = record_function(itype, itype.get_method(mi));
    object->_methods.push_back(function);
  }
  
  int num_casts = itype.number_of_casts();
  for (mi = 0; mi < num_casts; mi++) {
    function = record_function(itype, itype.get_cast(mi));
    object->_methods.push_back(function);
  }
  
  int num_derivations = itype.number_of_derivations();
  for (int di = 0; di < num_derivations; di++) {
    if (itype.derivation_has_upcast(di)) {
      record_function(itype, itype.derivation_get_upcast(di));
    }
    if (itype.derivation_has_downcast(di)) {
      // Downcasts are methods of the base class, not the child class.
      TypeIndex base_type_index = itype.get_derivation(di);
      const InterrogateType &base_type = idb->get_type(base_type_index);
      record_function(base_type, itype.derivation_get_downcast(di));
    }
  }

  int num_elements = itype.number_of_elements();
  for (int ei = 0; ei < num_elements; ei++) {
    ElementIndex element_index = itype.get_element(ei);
    const InterrogateElement &ielement = idb->get_element(element_index);
    if (ielement.has_getter()) {
      FunctionIndex func_index = ielement.get_getter();
      record_function(itype, func_index);
    }
    if (ielement.has_setter()) {
      FunctionIndex func_index = ielement.get_setter();
      record_function(itype, func_index);
    }
  }    

  int num_nested = itype.number_of_nested_types();
  for (int ni = 0; ni < num_nested; ni++) {
    TypeIndex nested_index = itype.get_nested_type(ni);
    record_object(nested_index);
  }

  return object;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::manage_return_value
//       Access: Protected
//  Description: Does any additional processing that we might want to
//               do on the return value for the function, just before
//               we return it.  Returns the string representing the
//               new return value after processing.
////////////////////////////////////////////////////////////////////
string InterfaceMaker::
manage_return_value(ostream &out, int indent_level,
                    FunctionRemap *remap, const string &return_expr) const {
  if (remap->_manage_reference_count) {
    // If we're managing reference counts, and we're about to return a
    // reference countable object, then increment its count.
    if (return_expr == "return_value") {
      // If the expression is just a variable name, we can just ref it
      // directly.
      output_ref(out, indent_level, remap, return_expr);
      return return_expr;

    } else {
      // Otherwise, we should probably assign it to a temporary first,
      // so we don't invoke the function twice or something.
      CPPType *type = remap->_return_type->get_temporary_type();
      indent(out, indent_level);
      type->output_instance(out, "refcount", &parser);
      out << " = " << return_expr << ";\n";

      indent(out, indent_level)
        << "if (" << return_expr << " != ("
        << remap->_return_type->get_new_type()->get_local_name(&parser) << ")0) {\n";
      indent(out, indent_level + 2)
        << return_expr << "->ref();\n";
      indent(out, indent_level)
        << "}\n";
      output_ref(out, indent_level, remap, "refcount");
      return remap->_return_type->temporary_to_return("refcount");
    }
  }

  // Otherwise, just return the expression unchanged.
  return return_expr;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::output_ref
//       Access: Protected
//  Description: Outputs the code to increment the reference count for
//               the indicated variable name.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
output_ref(ostream &out, int indent_level, FunctionRemap *remap, 
           const string &varname) const {
  if (remap->_type == FunctionRemap::T_constructor ||
      remap->_type == FunctionRemap::T_typecast) {
    // In either of these cases, we can safely assume the pointer will
    // never be NULL.
    indent(out, indent_level)
      << varname << "->ref();\n";

  } else {
    // However, in the general case, we have to check for that before
    // we attempt to ref it.

    indent(out, indent_level)
      << "if (" << varname << " != ("
      << remap->_return_type->get_new_type()->get_local_name(&parser) << ")0) {\n";
    indent(out, indent_level + 2)
      << varname << "->ref();\n";
    indent(out, indent_level)
      << "}\n";
  }
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::hash_function_signature
//       Access: Protected
//  Description: Generates a unique string that corresponds to the
//               function signature for the indicated FunctionRemap
//               object, and stores the generated string in the _hash
//               member of the FunctionRemap.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
hash_function_signature(FunctionRemap *remap) {
  string hash = InterrogateBuilder::hash_string(remap->_function_signature, 5);

  // Now make sure we don't have another function with the same hash.
  WrappersByHash::iterator hi;
  hi = _wrappers_by_hash.find(hash);
  if (hi == _wrappers_by_hash.end()) {
    // No other name; we're in the clear.
    _wrappers_by_hash[hash] = remap;
    remap->_hash = hash;
    return;
  }

  if ((*hi).second != (FunctionRemap *)NULL &&
      (*hi).second->_function_signature == remap->_function_signature) {
    // The same function signature has already appeared.  This
    // shouldn't happen.
    nout << "Internal error!  Function signature "
         << remap->_function_signature << " repeated!\n";
    remap->_hash = hash;
    abort(); 
    return;
  }

  // We have a conflict.  Extend both strings to resolve the
  // ambiguity.
  if ((*hi).second != (FunctionRemap *)NULL) {
    FunctionRemap *other_remap = (*hi).second;
    (*hi).second = (FunctionRemap *)NULL;
    other_remap->_hash +=
      InterrogateBuilder::hash_string(other_remap->_function_signature, 11);
    bool inserted = _wrappers_by_hash.insert
      (WrappersByHash::value_type(other_remap->_hash, other_remap)).second;
    if (!inserted) {
      nout << "Internal error!  Hash " << other_remap->_hash
           << " already appears!\n";
    }
  }

  hash += InterrogateBuilder::hash_string(remap->_function_signature, 11);
  bool inserted = _wrappers_by_hash.insert
    (WrappersByHash::value_type(hash, remap)).second;

  if (!inserted) {
    // Huh.  We still have a conflict.  This should be extremely rare.
    // Well, just tack on a letter until it's resolved.
    string old_hash = hash;
    for (char ch = 'a'; ch <= 'z' && !inserted; ch++) {
      hash = old_hash + ch;
      inserted = _wrappers_by_hash.insert
        (WrappersByHash::value_type(hash, remap)).second;
    }
    if (!inserted) {
      nout << "Internal error!  Too many conflicts with hash "
           << hash << "\n";
    }
  }

  remap->_hash = hash;
}

////////////////////////////////////////////////////////////////////
//     Function: InterfaceMaker::write_spam_message
//       Access: Protected
//  Description: Generates a string to output a spammy message to
//               notify indicating we have just called this function.
////////////////////////////////////////////////////////////////////
void InterfaceMaker::
write_spam_message(ostream &out, FunctionRemap *remap) const {
  ostringstream strm;
  remap->write_orig_prototype(strm, 0);
  string prototype = strm.str();

  out <<
    "  if (interrogatedb_cat.is_spam()) {\n"
    "    interrogatedb_cat.spam() << \"";

  for (string::const_iterator si = prototype.begin();
       si != prototype.end();
       ++si) {
    switch (*si) {
    case '"':
      out << "\\\"";
      break;

    case '\\':
      out << "\\\\";
      break;

    default:
      out << *si;
    }
  }

  out << "\\n\";\n"
    "  }\n";
}

---