1 /*
   2  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_REFLECTIONUTILS_HPP
  26 #define SHARE_VM_RUNTIME_REFLECTIONUTILS_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "oops/instanceKlass.hpp"
  30 #include "oops/objArrayOop.hpp"
  31 #include "oops/oopsHierarchy.hpp"
  32 #include "runtime/handles.inline.hpp"
  33 #include "runtime/reflection.hpp"
  34 #include "utilities/accessFlags.hpp"
  35 #include "utilities/globalDefinitions.hpp"
  36 
  37 // A KlassStream is an abstract stream for streaming over self, superclasses
  38 // and (super)interfaces. Streaming is done in reverse order (subclasses first,
  39 // interfaces last).
  40 //
  41 //    for (KlassStream st(k, false, false); !st.eos(); st.next()) {
  42 //      Klass* k = st.klass();
  43 //      ...
  44 //    }
  45 
  46 class KlassStream VALUE_OBJ_CLASS_SPEC {
  47  protected:
  48   instanceKlassHandle _klass;           // current klass/interface iterated over
  49   Array<Klass*>*    _interfaces;      // transitive interfaces for initial class
  50   int                 _interface_index; // current interface being processed
  51   bool                _local_only;      // process initial class/interface only
  52   bool                _classes_only;    // process classes only (no interfaces)
  53   int                 _index;
  54 
  55   virtual int length() const = 0;
  56 
  57  public:
  58   // constructor
  59   KlassStream(instanceKlassHandle klass, bool local_only, bool classes_only);
  60 
  61   // testing
  62   bool eos();
  63 
  64   // iterating
  65   virtual void next() = 0;
  66 
  67   // accessors
  68   instanceKlassHandle klass() const { return _klass; }
  69   int index() const                 { return _index; }
  70 };
  71 
  72 
  73 // A MethodStream streams over all methods in a class, superclasses and (super)interfaces.
  74 // Streaming is done in reverse order (subclasses first, methods in reverse order)
  75 // Usage:
  76 //
  77 //    for (MethodStream st(k, false, false); !st.eos(); st.next()) {
  78 //      Method* m = st.method();
  79 //      ...
  80 //    }
  81 
  82 class MethodStream : public KlassStream {
  83  private:
  84   int length() const          { return methods()->length(); }
  85   Array<Method*>* methods() const { return _klass->methods(); }
  86  public:
  87   MethodStream(instanceKlassHandle klass, bool local_only, bool classes_only)
  88     : KlassStream(klass, local_only, classes_only) {
  89     _index = length();
  90     next();
  91   }
  92 
  93   void next() { _index--; }
  94   Method* method() const { return methods()->at(index()); }
  95 };
  96 
  97 
  98 // A FieldStream streams over all fields in a class, superclasses and (super)interfaces.
  99 // Streaming is done in reverse order (subclasses first, fields in reverse order)
 100 // Usage:
 101 //
 102 //    for (FieldStream st(k, false, false); !st.eos(); st.next()) {
 103 //      Symbol* field_name = st.name();
 104 //      ...
 105 //    }
 106 
 107 
 108 class FieldStream : public KlassStream {
 109  private:
 110   int length() const                { return _klass->java_fields_count(); }
 111 
 112  public:
 113   FieldStream(instanceKlassHandle klass, bool local_only, bool classes_only)
 114     : KlassStream(klass, local_only, classes_only) {
 115     _index = length();
 116     next();
 117   }
 118 
 119   void next() { _index -= 1; }
 120 
 121   // Accessors for current field
 122   AccessFlags access_flags() const {
 123     AccessFlags flags;
 124     flags.set_flags(_klass->field_access_flags(_index));
 125     return flags;
 126   }
 127   Symbol* name() const {
 128     return _klass->field_name(_index);
 129   }
 130   Symbol* signature() const {
 131     return _klass->field_signature(_index);
 132   }
 133   // missing: initval()
 134   int offset() const {
 135     return _klass->field_offset( index() );
 136   }
 137 };
 138 
 139 class FilteredField : public CHeapObj<mtInternal>  {
 140  private:
 141   Klass* _klass;
 142   int    _field_offset;
 143 
 144  public:
 145   FilteredField(Klass* klass, int field_offset) {
 146     _klass = klass;
 147     _field_offset = field_offset;
 148   }
 149   Klass* klass() { return _klass; }
 150   int  field_offset() { return _field_offset; }
 151 };
 152 
 153 class FilteredFieldsMap : AllStatic {
 154  private:
 155   static GrowableArray<FilteredField *> *_filtered_fields;
 156  public:
 157   static void initialize();
 158   static bool is_filtered_field(Klass* klass, int field_offset) {
 159     for (int i=0; i < _filtered_fields->length(); i++) {
 160       if (klass == _filtered_fields->at(i)->klass() &&
 161         field_offset == _filtered_fields->at(i)->field_offset()) {
 162         return true;
 163       }
 164     }
 165     return false;
 166   }
 167   static int  filtered_fields_count(Klass* klass, bool local_only) {
 168     int nflds = 0;
 169     for (int i=0; i < _filtered_fields->length(); i++) {
 170       if (local_only && klass == _filtered_fields->at(i)->klass()) {
 171         nflds++;
 172       } else if (klass->is_subtype_of(_filtered_fields->at(i)->klass())) {
 173         nflds++;
 174       }
 175     }
 176     return nflds;
 177   }
 178   // Enhance Class Redefinition Support
 179   static void classes_do(KlassClosure* f) {
 180     for (int i = 0; i < _filtered_fields->length(); i++) {
 181       f->do_klass(_filtered_fields->at(i)->klass());
 182     }
 183   }
 184 };
 185 
 186 
 187 // A FilteredFieldStream streams over all fields in a class, superclasses and
 188 // (super)interfaces. Streaming is done in reverse order (subclasses first,
 189 // fields in reverse order)
 190 //
 191 // Usage:
 192 //
 193 //    for (FilteredFieldStream st(k, false, false); !st.eos(); st.next()) {
 194 //      Symbol* field_name = st.name();
 195 //      ...
 196 //    }
 197 
 198 class FilteredFieldStream : public FieldStream {
 199  private:
 200   int  _filtered_fields_count;
 201   bool has_filtered_field() { return (_filtered_fields_count > 0); }
 202 
 203  public:
 204   FilteredFieldStream(instanceKlassHandle klass, bool local_only, bool classes_only)
 205     : FieldStream(klass, local_only, classes_only) {
 206     _filtered_fields_count = FilteredFieldsMap::filtered_fields_count((Klass*)klass(), local_only);
 207   }
 208   int field_count();
 209   void next() {
 210     _index -= 1;
 211     if (has_filtered_field()) {
 212       while (_index >=0 && FilteredFieldsMap::is_filtered_field((Klass*)_klass(), offset())) {
 213         _index -= 1;
 214       }
 215     }
 216   }
 217 };
 218 
 219 #endif // SHARE_VM_RUNTIME_REFLECTIONUTILS_HPP