/*

 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_VM_RUNTIME_REFLECTIONUTILS_HPP

#define SHARE_VM_RUNTIME_REFLECTIONUTILS_HPP

#include "memory/allocation.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/objArrayOop.hpp"

#include "oops/oopsHierarchy.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/reflection.hpp"

#include "utilities/accessFlags.hpp"

#include "utilities/globalDefinitions.hpp"

// A KlassStream is an abstract stream for streaming over self, superclasses

// and (super)interfaces. Streaming is done in reverse order (subclasses first,

// interfaces last).

//

//    for (KlassStream st(k, false, false, false); !st.eos(); st.next()) {

//      Klass* k = st.klass();

//      ...

//    }

class KlassStream VALUE_OBJ_CLASS_SPEC {

 protected:

  InstanceKlass*      _klass;           // current klass/interface iterated over

  InstanceKlass*      _base_klass;      // initial klass/interface to iterate over

  Array<Klass*>*      _interfaces;      // transitive interfaces for initial class

  int                 _interface_index; // current interface being processed

  bool                _local_only;      // process initial class/interface only

  bool                _classes_only;    // process classes only (no interfaces)

  bool                _walk_defaults;   // process default methods

  bool                _base_class_search_defaults; // time to process default methods

  bool                _defaults_checked; // already checked for default methods

  int                 _index;

  virtual int length() = 0;

 public:

  // constructor

  KlassStream(InstanceKlass* klass, bool local_only, bool classes_only, bool walk_defaults);

  // testing

  bool eos();

  // iterating

  virtual void next() = 0;

  // accessors

  InstanceKlass* klass() const      { return _klass; }

  int index() const                 { return _index; }

  bool base_class_search_defaults() const { return _base_class_search_defaults; }

  void base_class_search_defaults(bool b) { _base_class_search_defaults = b; }

};

// A MethodStream streams over all methods in a class, superclasses and (super)interfaces.

// Streaming is done in reverse order (subclasses first, methods in reverse order)

// Usage:

//

//    for (MethodStream st(k, false, false); !st.eos(); st.next()) {

//      Method* m = st.method();

//      ...

//    }

class MethodStream : public KlassStream {

 private:

  int length()                    { return methods()->length(); }

  Array<Method*>* methods() {

    if (base_class_search_defaults()) {

      base_class_search_defaults(false);

      return _klass->default_methods();

    } else {

      return _klass->methods();

    }

  }

 public:

  MethodStream(InstanceKlass* klass, bool local_only, bool classes_only)

    : KlassStream(klass, local_only, classes_only, true) {

    _index = length();

    next();

  }

  void next() { _index--; }

  Method* method() { return methods()->at(index()); }

};

// A FieldStream streams over all fields in a class, superclasses and (super)interfaces.

// Streaming is done in reverse order (subclasses first, fields in reverse order)

// Usage:

//

//    for (FieldStream st(k, false, false); !st.eos(); st.next()) {

//      Symbol* field_name = st.name();

//      ...

//    }

class FieldStream : public KlassStream {

 private:

  int length() { return _klass->java_fields_count(); }

  fieldDescriptor _fd_buf;

 public:

  FieldStream(InstanceKlass* klass, bool local_only, bool classes_only)

    : KlassStream(klass, local_only, classes_only, false) {

    _index = length();

    next();

  }

  void next() { _index -= 1; }

  // Accessors for current field

  AccessFlags access_flags() const {

    AccessFlags flags;

    flags.set_flags(_klass->field_access_flags(_index));

    return flags;

  }

  Symbol* name() const {

    return _klass->field_name(_index);

  }

  Symbol* signature() const {

    return _klass->field_signature(_index);

  }

  // missing: initval()

  int offset() const {

    return _klass->field_offset( index() );

  }

  // bridge to a heavier API:

  fieldDescriptor& field_descriptor() const {

    fieldDescriptor& field = const_cast<fieldDescriptor&>(_fd_buf);

    field.reinitialize(_klass, _index);

    return field;

  }

};

class FilteredField : public CHeapObj<mtInternal>  {

 private:

  Klass* _klass;

  int    _field_offset;

 public:

  FilteredField(Klass* klass, int field_offset) {

    _klass = klass;

    _field_offset = field_offset;

  }

  Klass* klass() { return _klass; }

  int  field_offset() { return _field_offset; }

};

class FilteredFieldsMap : AllStatic {

 private:

  static GrowableArray<FilteredField *> *_filtered_fields;

 public:

  static void initialize();

  static bool is_filtered_field(Klass* klass, int field_offset) {

    for (int i=0; i < _filtered_fields->length(); i++) {

      if (klass == _filtered_fields->at(i)->klass() &&

        field_offset == _filtered_fields->at(i)->field_offset()) {

        return true;

      }

    }

    return false;

  }

  static int  filtered_fields_count(Klass* klass, bool local_only) {

    int nflds = 0;

    for (int i=0; i < _filtered_fields->length(); i++) {

      if (local_only && klass == _filtered_fields->at(i)->klass()) {

        nflds++;

      } else if (klass->is_subtype_of(_filtered_fields->at(i)->klass())) {

        nflds++;

      }

    }

    return nflds;

  }

};

// A FilteredFieldStream streams over all fields in a class, superclasses and

// (super)interfaces. Streaming is done in reverse order (subclasses first,

// fields in reverse order)

//

// Usage:

//

//    for (FilteredFieldStream st(k, false, false); !st.eos(); st.next()) {

//      Symbol* field_name = st.name();

//      ...

//    }

class FilteredFieldStream : public FieldStream {

 private:

  int  _filtered_fields_count;

  bool has_filtered_field() { return (_filtered_fields_count > 0); }

 public:

  FilteredFieldStream(InstanceKlass* klass, bool local_only, bool classes_only)

    : FieldStream(klass, local_only, classes_only) {

    _filtered_fields_count = FilteredFieldsMap::filtered_fields_count(klass, local_only);

  }

  int field_count();

  void next() {

    _index -= 1;

    if (has_filtered_field()) {

      while (_index >=0 && FilteredFieldsMap::is_filtered_field((Klass*)_klass, offset())) {

        _index -= 1;

      }

    }

  }

};

#endif // SHARE_VM_RUNTIME_REFLECTIONUTILS_HPP