/*

 * Copyright (c) 2003, 2018, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/symbolTable.hpp"

#include "classfile/systemDictionaryShared.hpp"

#include "classfile/verificationType.hpp"

#include "classfile/verifier.hpp"

#include "logging/log.hpp"

#include "runtime/handles.inline.hpp"

VerificationType VerificationType::from_tag(u1 tag) {

  switch (tag) {

    case ITEM_Top:     return bogus_type();

    case ITEM_Integer: return integer_type();

    case ITEM_Float:   return float_type();

    case ITEM_Double:  return double_type();

    case ITEM_Long:    return long_type();

    case ITEM_Null:    return null_type();

    default:

      ShouldNotReachHere();

      return bogus_type();

  }

}

bool VerificationType::resolve_and_check_assignability(InstanceKlass* klass, Symbol* name,

         Symbol* from_name, bool from_field_is_protected, bool from_is_array, bool from_is_object, TRAPS) {

  HandleMark hm(THREAD);

  Klass* this_class = SystemDictionary::resolve_or_fail(

      name, Handle(THREAD, klass->class_loader()),

      Handle(THREAD, klass->protection_domain()), true, CHECK_false);

  klass->class_loader_data()->record_dependency(this_class);

  if (log_is_enabled(Debug, class, resolve)) {

    Verifier::trace_class_resolution(this_class, klass);

  }

  if (this_class->is_interface() && (!from_field_is_protected ||

      from_name != vmSymbols::java_lang_Object())) {

    // If we are not trying to access a protected field or method in

    // java.lang.Object then, for arrays, we only allow assignability

    // to interfaces java.lang.Cloneable and java.io.Serializable.

    // Otherwise, we treat interfaces as java.lang.Object.

    return !from_is_array ||

      this_class == SystemDictionary::Cloneable_klass() ||

      this_class == SystemDictionary::Serializable_klass();

  } else if (from_is_object) {

    Klass* from_class = SystemDictionary::resolve_or_fail(

        from_name, Handle(THREAD, klass->class_loader()),

        Handle(THREAD, klass->protection_domain()), true, CHECK_false);

    klass->class_loader_data()->record_dependency(from_class);

    if (log_is_enabled(Debug, class, resolve)) {

      Verifier::trace_class_resolution(from_class, klass);

    }

    return InstanceKlass::cast(from_class)->is_subclass_of(this_class);

  }

  return false;

}

bool VerificationType::is_reference_assignable_from(

    const VerificationType& from, ClassVerifier* context,

    bool from_field_is_protected, TRAPS) const {

  InstanceKlass* klass = context->current_class();

  if (from.is_null()) {

    // null is assignable to any reference

    return true;

  } else if (is_null()) {

    return false;

  } else if (name() == from.name()) {

    return true;

  } else if (is_object()) {

    // We need check the class hierarchy to check assignability

    if (name() == vmSymbols::java_lang_Object()) {

      // any object or array is assignable to java.lang.Object

      return true;

    }

    if (DumpSharedSpaces && SystemDictionaryShared::add_verification_constraint(klass,

              name(), from.name(), from_field_is_protected, from.is_array(),

              from.is_object())) {

      // If add_verification_constraint() returns true, the resolution/check should be

      // delayed until runtime.

      return true;

    }

    return resolve_and_check_assignability(klass, name(), from.name(),

          from_field_is_protected, from.is_array(), from.is_object(), THREAD);

  } else if (is_array() && from.is_array()) {

    VerificationType comp_this = get_component(context, CHECK_false);

    VerificationType comp_from = from.get_component(context, CHECK_false);

    if (!comp_this.is_bogus() && !comp_from.is_bogus()) {

      return comp_this.is_component_assignable_from(comp_from, context,

                                          from_field_is_protected, CHECK_false);

    }

  }

  return false;

}

VerificationType VerificationType::get_component(ClassVerifier *context, TRAPS) const {

  assert(is_array() && name()->utf8_length() >= 2, "Must be a valid array");

  Symbol* component;

  switch (name()->byte_at(1)) {

    case 'Z': return VerificationType(Boolean);

    case 'B': return VerificationType(Byte);

    case 'C': return VerificationType(Char);

    case 'S': return VerificationType(Short);

    case 'I': return VerificationType(Integer);

    case 'J': return VerificationType(Long);

    case 'F': return VerificationType(Float);

    case 'D': return VerificationType(Double);

    case '[':

      component = context->create_temporary_symbol(

        name(), 1, name()->utf8_length(),

        CHECK_(VerificationType::bogus_type()));

      return VerificationType::reference_type(component);

    case 'L':

      component = context->create_temporary_symbol(

        name(), 2, name()->utf8_length() - 1,

        CHECK_(VerificationType::bogus_type()));

      return VerificationType::reference_type(component);

    default:

      // Met an invalid type signature, e.g. [X

      return VerificationType::bogus_type();

  }

}

void VerificationType::print_on(outputStream* st) const {

  switch (_u._data) {

    case Bogus:            st->print("top"); break;

    case Category1:        st->print("category1"); break;

    case Category2:        st->print("category2"); break;

    case Category2_2nd:    st->print("category2_2nd"); break;

    case Boolean:          st->print("boolean"); break;

    case Byte:             st->print("byte"); break;

    case Short:            st->print("short"); break;

    case Char:             st->print("char"); break;

    case Integer:          st->print("integer"); break;

    case Float:            st->print("float"); break;

    case Long:             st->print("long"); break;

    case Double:           st->print("double"); break;

    case Long_2nd:         st->print("long_2nd"); break;

    case Double_2nd:       st->print("double_2nd"); break;

    case Null:             st->print("null"); break;

    case ReferenceQuery:   st->print("reference type"); break;

    case Category1Query:   st->print("category1 type"); break;

    case Category2Query:   st->print("category2 type"); break;

    case Category2_2ndQuery: st->print("category2_2nd type"); break;

    default:

      if (is_uninitialized_this()) {

        st->print("uninitializedThis");

      } else if (is_uninitialized()) {

        st->print("uninitialized %d", bci());

      } else {

        name()->print_value_on(st);

      }

  }

}