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

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 * published by the Free Software Foundation.

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 * 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.

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package sun.jvm.hotspot.debugger;

/** <P> This is the bottom-most interface which abstracts address

    access for both debugging and introspection. In the situation of

    debugging a target VM, these routines can throw the specified

    RuntimeExceptions to indicate failure and allow recovery of the

    debugging system. If these are used for introspecting the current

    VM and implementing functionality in it, however, it is expected

    that these kinds of failures will not occur and, in fact, a crash

    will occur if the situation arises where they would have been

    thrown. </P>

    <P> Addresses are immutable. Further, it was decided not to expose

    the representation of the Address (and provide a corresponding

    factory method from, for example, long to Address). Unfortunately,

    because of the existence of C and "reuse" of low bits of pointers,

    it is occasionally necessary to perform logical operations like

    masking off the low bits of an "address". While these operations

    could be used to generate arbitrary Address objects, allowing this

    is not the intent of providing these operations. </P>

    <P> This interface is able to fetch all Java primitive types,

    addresses, oops, and C integers of arbitrary size (see @see

    sun.jvm.hotspot.types.CIntegerType for further discussion). Note

    that the result of the latter is restricted to fitting into a

    64-bit value and the high-order bytes will be silently discarded

    if too many bytes are requested. </P>

    <P> Implementations may have restrictions, for example that the

    Java-related routines may not be called until a certain point in

    the bootstrapping process once the sizes of the Java primitive

    types are known. (The current implementation has that property.)

    </P>

    <P> A note of warning: in C addresses, when represented as

    integers, are usually represented with unsigned types.

    Unfortunately, there are no unsigned primitive types in Java, so

    care will have to be taken in the implementation of this interface

    if using longs as the representation for 64-bit correctness. This

    is not so simple for the comparison operators. </P> */

public interface Address {

  /** This is stated explicitly here because it is important for

      implementations to understand that equals() and hashCode() must

      absolutely, positively work properly -- i.e., two Address

      objects representing the same address are both equal (via

      equals()) and have the same hash code. */

  public boolean equals(Object arg);

  /** This is stated explicitly here because it is important for

      implementations to understand that equals() and hashCode() must

      absolutely, positively work properly -- i.e., two Address

      objects representing the same address are both equal (via

      equals()) and have the same hash code. */

  public int hashCode();

  //

  // C/C++-related routines

  //

  public long       getCIntegerAt      (long offset, long numBytes, boolean isUnsigned)

    throws UnmappedAddressException, UnalignedAddressException;

  /** This returns null if the address at the given offset is NULL. */

  public Address    getAddressAt       (long offset) throws UnmappedAddressException, UnalignedAddressException;

  /** Returns the decoded address at the given offset */

  public Address    getCompOopAddressAt (long offset) throws UnmappedAddressException, UnalignedAddressException;

  //

  // Java-related routines

  //

  public boolean    getJBooleanAt      (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public byte       getJByteAt         (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public char       getJCharAt         (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public double     getJDoubleAt       (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public float      getJFloatAt        (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public int        getJIntAt          (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public long       getJLongAt         (long offset) throws UnmappedAddressException, UnalignedAddressException;

  public short      getJShortAt        (long offset) throws UnmappedAddressException, UnalignedAddressException;

  /** This returns null if the address at the given offset is NULL. */

  public OopHandle  getOopHandleAt     (long offset)

    throws UnmappedAddressException, UnalignedAddressException, NotInHeapException;

  public OopHandle  getCompOopHandleAt (long offset)

    throws UnmappedAddressException, UnalignedAddressException, NotInHeapException;

  //

  // C/C++-related mutators. These throw UnmappedAddressException if

  // the target is read-only (for example, a core file rather than an

  // active process), if the target address is unmapped, or if it is

  // read-only. The implementation may supply extra detail messages.

  //

  /** Sets a C integer numBytes in size at the specified offset. Note

      that there is no "unsigned" flag for the accessor since the

      value will not be sign-extended; the number of bytes are simply

      copied from the value into the target address space. */

  public void setCIntegerAt(long offset, long numBytes, long value);

  /** Sets an Address at the specified location. */

  public void setAddressAt(long offset, Address value);

  //

  // Java-related mutators -- see above.

  //

  public void       setJBooleanAt      (long offset, boolean value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJByteAt         (long offset, byte value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJCharAt         (long offset, char value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJDoubleAt       (long offset, double value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJFloatAt        (long offset, float value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJIntAt          (long offset, int value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJLongAt         (long offset, long value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setJShortAt        (long offset, short value)

    throws UnmappedAddressException, UnalignedAddressException;

  public void       setOopHandleAt     (long offset, OopHandle value)

    throws UnmappedAddressException, UnalignedAddressException;

  //

  // Arithmetic operations -- necessary evil.

  //

  /** This throws an UnsupportedOperationException if this address happens

      to actually be an OopHandle, because interior object pointers

      are not allowed. Negative offsets are allowed and handle the

      subtraction case. */

  public Address    addOffsetTo        (long offset) throws UnsupportedOperationException;

  /** This method had to be added in order to support heap iteration

      in the debugging system, and is effectively the dangerous

      operation of allowing interior object pointers. For this reason

      it was kept as a separate API and its use is forbidden in the

      non-debugging (i.e., reflective system) case. It is strongly

      recommended that this not be called by clients: it is currently

      wrapped up in the Space's iteration mechanism. */

  public OopHandle  addOffsetToAsOopHandle(long offset) throws UnsupportedOperationException;

  /** Performs the subtraction "this - arg", returning the resulting

      offset in bytes. Note that this must handle a null argument

      properly, and can be used to convert an Address into a long for

      further manipulation, but that the reverse conversion is not

      possible. (FIXME: any signed/unsigned issues? Should this work

      for OopHandles?) */

  public long       minus(Address arg);

  /** Performs unsigned comparison "this < arg".

      (FIXME: should this work for OopHandles?) */

  public boolean    lessThan          (Address arg);

  /** Performs unsigned comparison "this <= arg".

      (FIXME: should this work for OopHandles?) */

  public boolean    lessThanOrEqual   (Address arg);

  /** Performs unsigned comparison "this > arg".

      (FIXME: should this work for OopHandles?) */

  public boolean    greaterThan       (Address arg);

  /** Performs unsigned comparison "this >= arg".

      (FIXME: should this work for OopHandles?) */

  public boolean    greaterThanOrEqual(Address arg);

  /** This throws an UnsupportedOperationException if this address happens

      to actually be an OopHandle. Performs a logical "and" operation

      of the bits of the address and the mask (least significant bits

      of the Address and the mask are aligned) and returns the result

      as an Address. Returns null if the result was zero. */

  public Address    andWithMask(long mask) throws UnsupportedOperationException;

  /** This throws an UnsupportedOperationException if this address happens

      to actually be an OopHandle. Performs a logical "or" operation

      of the bits of the address and the mask (least significant bits

      of the Address and the mask are aligned) and returns the result

      as an Address. Returns null if the result was zero. */

  public Address    orWithMask(long mask) throws UnsupportedOperationException;

  /** This throws an UnsupportedOperationException if this address happens

      to actually be an OopHandle. Performs a logical "exclusive or"

      operation of the bits of the address and the mask (least

      significant bits of the Address and the mask are aligned) and

      returns the result as an Address. Returns null if the result was

      zero. */

  public Address    xorWithMask(long mask) throws UnsupportedOperationException;

}