Java example source code file (decoder.cpp)

This example Java source code file (decoder.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

abstractdecoder, decoder\:\:create_decoder, decoder\:\:decode, decoder\:\:get_error_handler_instance, decoder\:\:get_shared_instance, decoder\:\:shared_decoder_lock, decoderlocker\:\:decoderlocker, decoderlocker\:\:is_first_error_thread, just, mutexlockerex, null, nulldecoder, vmerror\:\:first_error_tid, windowsdecoder

The decoder.cpp Java example source code

/*
 * Copyright (c) 1997, 2013, 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 "prims/jvm.h"
#include "runtime/os.hpp"
#include "utilities/decoder.hpp"
#include "utilities/vmError.hpp"

#if defined(_WINDOWS)
  #include "decoder_windows.hpp"
#elif defined(__APPLE__)
  #include "decoder_machO.hpp"
#else
  #include "decoder_elf.hpp"
#endif

AbstractDecoder*  Decoder::_shared_decoder = NULL;
AbstractDecoder*  Decoder::_error_handler_decoder = NULL;
NullDecoder       Decoder::_do_nothing_decoder;
Mutex*            Decoder::_shared_decoder_lock = new Mutex(Mutex::native,
                                "SharedDecoderLock");

AbstractDecoder* Decoder::get_shared_instance() {
  assert(_shared_decoder_lock != NULL && _shared_decoder_lock->owned_by_self(),
    "Require DecoderLock to enter");

  if (_shared_decoder == NULL) {
    _shared_decoder = create_decoder();
  }
  return _shared_decoder;
}

AbstractDecoder* Decoder::get_error_handler_instance() {
  if (_error_handler_decoder == NULL) {
    _error_handler_decoder = create_decoder();
  }
  return _error_handler_decoder;
}


AbstractDecoder* Decoder::create_decoder() {
  AbstractDecoder* decoder;
#if defined(_WINDOWS)
  decoder = new (std::nothrow) WindowsDecoder();
#elif defined (__APPLE__)
  decoder = new (std::nothrow)MachODecoder();
#else
  decoder = new (std::nothrow)ElfDecoder();
#endif

  if (decoder == NULL || decoder->has_error()) {
    if (decoder != NULL) {
      delete decoder;
    }
    decoder = &_do_nothing_decoder;
  }
  return decoder;
}

inline bool DecoderLocker::is_first_error_thread() {
  return (os::current_thread_id() == VMError::get_first_error_tid());
}

DecoderLocker::DecoderLocker() :
  MutexLockerEx(DecoderLocker::is_first_error_thread() ?
                NULL : Decoder::shared_decoder_lock(), true) {
  _decoder = is_first_error_thread() ?
    Decoder::get_error_handler_instance() : Decoder::get_shared_instance();
  assert(_decoder != NULL, "null decoder");
}

Mutex* Decoder::shared_decoder_lock() {
  assert(_shared_decoder_lock != NULL, "Just check");
  return _shared_decoder_lock;
}

bool Decoder::decode(address addr, char* buf, int buflen, int* offset, const char* modulepath) {
  assert(_shared_decoder_lock != NULL, "Just check");
  bool error_handling_thread = os::current_thread_id() == VMError::first_error_tid;
  MutexLockerEx locker(error_handling_thread ? NULL : _shared_decoder_lock, true);
  AbstractDecoder* decoder = error_handling_thread ?
    get_error_handler_instance(): get_shared_instance();
  assert(decoder != NULL, "null decoder");

  return decoder->decode(addr, buf, buflen, offset, modulepath);
}

bool Decoder::decode(address addr, char* buf, int buflen, int* offset, const void* base) {
  assert(_shared_decoder_lock != NULL, "Just check");
  bool error_handling_thread = os::current_thread_id() == VMError::first_error_tid;
  MutexLockerEx locker(error_handling_thread ? NULL : _shared_decoder_lock, true);
  AbstractDecoder* decoder = error_handling_thread ?
    get_error_handler_instance(): get_shared_instance();
  assert(decoder != NULL, "null decoder");

  return decoder->decode(addr, buf, buflen, offset, base);
}


bool Decoder::demangle(const char* symbol, char* buf, int buflen) {
  assert(_shared_decoder_lock != NULL, "Just check");
  bool error_handling_thread = os::current_thread_id() == VMError::first_error_tid;
  MutexLockerEx locker(error_handling_thread ? NULL : _shared_decoder_lock, true);
  AbstractDecoder* decoder = error_handling_thread ?
    get_error_handler_instance(): get_shared_instance();
  assert(decoder != NULL, "null decoder");
  return decoder->demangle(symbol, buf, buflen);
}

bool Decoder::can_decode_C_frame_in_vm() {
  assert(_shared_decoder_lock != NULL, "Just check");
  bool error_handling_thread = os::current_thread_id() == VMError::first_error_tid;
  MutexLockerEx locker(error_handling_thread ? NULL : _shared_decoder_lock, true);
  AbstractDecoder* decoder = error_handling_thread ?
    get_error_handler_instance(): get_shared_instance();
  assert(decoder != NULL, "null decoder");
  return decoder->can_decode_C_frame_in_vm();
}

/*
 * Shutdown shared decoder and replace it with
 * _do_nothing_decoder. Do nothing with error handler
 * instance, since the JVM is going down.
 */
void Decoder::shutdown() {
  assert(_shared_decoder_lock != NULL, "Just check");
  MutexLockerEx locker(_shared_decoder_lock, true);

  if (_shared_decoder != NULL &&
    _shared_decoder != &_do_nothing_decoder) {
    delete _shared_decoder;
  }

  _shared_decoder = &_do_nothing_decoder;
}