/*

 * Copyright (c) 1997, 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.

 *

 */

#ifndef SHARE_VM_UTILITIES_DECODER_HPP

#define SHARE_VM_UTILITIES_DECODER_HPP

#include "memory/allocation.hpp"

#include "runtime/mutex.hpp"

class AbstractDecoder : public CHeapObj<mtInternal> {

public:

  // status code for decoding native C frame

  enum decoder_status {

         not_available = -10,  // real decoder is not available

         no_error = 0,         // successfully decoded frames

         out_of_memory,        // out of memory

         file_invalid,         // invalid elf file

         file_not_found,       // could not found symbol file (on windows), such as jvm.pdb or jvm.map

         helper_not_found,     // could not load dbghelp.dll (Windows only)

         helper_func_error,    // decoding functions not found (Windows only)

         helper_init_error     // SymInitialize failed (Windows only)

  };

  // decode an pc address to corresponding function name and an offset from the beginning of

  // the function

  virtual bool decode(address pc, char* buf, int buflen, int* offset,

    const char* modulepath = NULL) = 0;

  // demangle a C++ symbol

  virtual bool demangle(const char* symbol, char* buf, int buflen) = 0;

  // if the decoder can decode symbols in vm

  virtual bool can_decode_C_frame_in_vm() const = 0;

  virtual decoder_status status() const {

    return _decoder_status;

  }

  virtual bool has_error() const {

    return is_error(_decoder_status);

  }

  static bool is_error(decoder_status status) {

    return (status > 0);

  }

protected:

  decoder_status  _decoder_status;

};

// Do nothing decoder

class NullDecoder : public AbstractDecoder {

public:

  NullDecoder() {

    _decoder_status = not_available;

  }

  ~NullDecoder() {};

  virtual bool decode(address pc, char* buf, int buflen, int* offset,

    const char* modulepath = NULL) {

    return false;

  }

  virtual bool demangle(const char* symbol, char* buf, int buflen) {

    return false;

  }

  virtual bool can_decode_C_frame_in_vm() const {

    return false;

  }

};

class Decoder : AllStatic {

public:

  static bool decode(address pc, char* buf, int buflen, int* offset, const char* modulepath = NULL);

  static bool demangle(const char* symbol, char* buf, int buflen);

  static bool can_decode_C_frame_in_vm();

  // shutdown shared instance

  static void shutdown();

protected:

  // shared decoder instance, _shared_instance_lock is needed

  static AbstractDecoder* get_shared_instance();

  // a private instance for error handler. Error handler can be

  // triggered almost everywhere, including signal handler, where

  // no lock can be taken. So the shared decoder can not be used

  // in this scenario.

  static AbstractDecoder* get_error_handler_instance();

  static AbstractDecoder* create_decoder();

private:

  static AbstractDecoder*     _shared_decoder;

  static AbstractDecoder*     _error_handler_decoder;

  static NullDecoder          _do_nothing_decoder;

protected:

  static Mutex*               _shared_decoder_lock;

};

#endif // SHARE_VM_UTILITIES_DECODER_HPP