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Java example source code file (verificationType.cpp)

This example Java source code file (verificationType.cpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

byte, check_false, handle, instanceklass\:\:cast, item_null, klass, null, shouldnotreachhere, systemdictionary\:\:resolve_or_fail, traps, verificationtype, verificationtype\:\:bogus_type, verificationtype\:\:reference_type

The verificationType.cpp Java example source code

/*
 * Copyright (c) 2003, 2012, 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/verificationType.hpp"
#include "classfile/verifier.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::is_reference_assignable_from(
    const VerificationType& from, ClassVerifier* context, TRAPS) const {
  instanceKlassHandle 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;
    }
    Klass* obj = SystemDictionary::resolve_or_fail(
        name(), Handle(THREAD, klass->class_loader()),
        Handle(THREAD, klass->protection_domain()), true, CHECK_false);
    KlassHandle this_class(THREAD, obj);

    if (this_class->is_interface()) {
      // We treat interfaces as java.lang.Object, including
      // java.lang.Cloneable and java.io.Serializable
      return true;
    } 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);
      return InstanceKlass::cast(from_class)->is_subclass_of(this_class());
    }
  } 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_assignable_from(comp_from, context, 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);
      }
  }
}

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