1 /*
   2  * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved.
   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  */
  25 package sun.jvm.hotspot.types;
  27 import java.util.Iterator;
  28 import sun.jvm.hotspot.debugger.Address;
  30 public interface TypeDataBase {
  31   /** Equivalent to lookupType(cTypeName, true) */
  32   public Type lookupType(String cTypeName);
  34   /** For simplicity of the initial implementation, this is not
  35       guaranteed to work for primitive types. If throwException is
  36       true, throws an (unspecified) run-time exception if the type is
  37       not found. */
  38   public Type lookupType(String cTypeName, boolean throwException);
  40   /** Equivalent to lookupIntConstant(constantName, true) */
  41   public Integer lookupIntConstant(String constantName);
  43   /* For convenience, this interface also encapsulates the fetching of
  44      integer constants, i.e., enums. If no constant of this name was
  45      present, either throws an (unspecified) run-time exception or
  46      returns null. */
  47   public Integer lookupIntConstant(String constantName, boolean throwException);
  49   /** Equivalent to lookupLongConstant(constantName, true) */
  50   public Long lookupLongConstant(String constantName);
  52   /* For convenience, this interface also encapsulates the fetching of
  53      long constants (those requiring 64 bits on 64-bit platforms). If
  54      no constant of this name was present, either throws an
  55      (unspecified) run-time exception or returns null. */
  56   public Long lookupLongConstant(String constantName, boolean throwException);
  58   /** Accessors for types representing the Java primitive types; used
  59       for both proper type checking and for walking down Java arrays. */
  60   public Type getJBooleanType();
  61   public Type getJByteType();
  62   public Type getJCharType();
  63   public Type getJDoubleType();
  64   public Type getJFloatType();
  65   public Type getJIntType();
  66   public Type getJLongType();
  67   public Type getJShortType();
  69   /** Returns the size of a C address in bytes. This is currently
  70       needed in order to properly traverse an array of pointers.
  71       Traversing an array of structs, for example, is possible by
  72       looking up the type of the struct and multiplying the index by
  73       its size when indexing off of a base Address. (FIXME: what about
  74       alignment?) */
  75   public long getAddressSize();
  77   /** Returns the size of an oop in bytes. This is currently needed in
  78       order to properly traverse an array of oops; it is distinguished
  79       from the address size, above, because object pointers could
  80       conceivably have a different representation than direct
  81       pointers. Traversing an array of structs, for example, is
  82       possible by looking up the type of the struct and multiplying
  83       the index by its size when indexing off of a base Address. */
  84   public long getOopSize();
  86   /** <P> This is an experimental interface emulating C++'s run-time
  87       type information (RTTI) mechanism: determines whether the given
  88       address is a pointer to the start of a C++ object of precisely
  89       the given type -- it does not search superclasses of the type.
  90       The convention is that this returns false for the null pointer.
  91       It is needed to allow wrapper Java objects of the appropriate
  92       type to be constructed for existing C++ objects of polymorphic
  93       type. This method is only intended to work for C++ types
  94       (implying that we should rename this package and the classes
  95       contained within back to "ctypes"). Further, since the vptr
  96       offset in an object is known at compile time but not necessarily
  97       at runtime (unless debugging information is available), it is
  98       reasonable for an implementation of this method to search nearby
  99       memory for the (known) vtbl value for the given type. For this
 100       reason, this method is not intended to support scans through
 101       memory finding C++ objects, but is instead targeted towards
 102       discovering the true type of a pointer assumed to be
 103       intact. </P>
 105       <P> The reason this method was placed in the type database is
 106       that the latter is the first level at which it could be exposed,
 107       and placing it here could avoid modifying the Type interface. It
 108       is unclear what other, if any, vtbl access would be useful (or
 109       implementable), so we are trying to avoid changing interfaces at
 110       this point to support this kind of functionality. </P>
 112       <P> This method necessarily does not support multiple
 113       inheritance. </P> */
 114   public boolean addressTypeIsEqualToType(Address addr, Type type);
 116   /** Helper routine for guessing the most derived type of a
 117       polymorphic C++ object. Iterates the type database calling
 118       addressTypeIsEqualToType for all known types. Returns a matching
 119       Type for the given address if one was found, or null if none was
 120       found. */
 121   public Type guessTypeForAddress(Address addr);
 123   /** Returns an Iterator over the Types in the database. */
 124   public Iterator getTypes();
 126   /** Returns an Iterator over the String names of the integer
 127       constants in the database. */
 128   public Iterator getIntConstants();
 130   /** Returns an Iterator over the String names of the long constants
 131       in the database. */
 132   public Iterator getLongConstants();
 133 }