/*

 * Copyright (c) 2014, 2019, 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_CLASSFILE_SHAREDPATHSMISCINFO_HPP

#define SHARE_CLASSFILE_SHAREDPATHSMISCINFO_HPP

#include "classfile/classLoader.hpp"

#include "runtime/os.hpp"

class outputStream;

// During dumping time, when processing class paths, we build up the dump-time

// classpath. The JAR files that exist are stored in the list ClassLoader::_first_append_entry.

// However, we need to store other "misc" information for run-time checking, such as

//

// + The values of Arguments::get_sysclasspath() used during dumping.

//

// + The class path elements specified during dumping but did not exist --

//   these elements must also be specified at run time, and they also must not

//   exist at run time.

//

// These misc items are stored in a linear buffer in SharedPathsMiscInfo.

// The storage format is stream oriented to minimize its size.

//

// When writing the information to the archive file, SharedPathsMiscInfo is stored in

// the archive file header. At run-time, this information is used only during initialization

// (accessed using read() instead of mmap()), and is deallocated afterwards to save space.

//

// The SharedPathsMiscInfo class is used for both creating the the information (during

// dumping time) and validation (at run time). Different constructors are used in the

// two situations. See below.

class SharedPathsMiscInfo : public CHeapObj<mtClass> {

private:

  int   _app_offset;

protected:

  char* _buf_start;

  char* _cur_ptr;

  char* _end_ptr;

  int   _buf_size;

  bool  _allocated;   // was _buf_start allocated by me?

  void ensure_size(size_t needed_bytes);

  void add_path(const char* path, int type);

  void write(const void* ptr, size_t size);

  bool read(void* ptr, size_t size);

protected:

  static bool fail(const char* msg, const char* name = NULL);

public:

  enum {

    INITIAL_BUF_SIZE = 128

  };

  // This constructor is used when creating the misc information (during dump)

  SharedPathsMiscInfo();

  // This constructor is used when validating the misc info (during run time)

  SharedPathsMiscInfo(char *buff, int size) {

    _app_offset = 0;

    _cur_ptr = _buf_start = buff;

    _end_ptr = _buf_start + size;

    _buf_size = size;

    _allocated = false;

  }

  ~SharedPathsMiscInfo();

  int get_used_bytes() {

    return _cur_ptr - _buf_start;

  }

  void* buffer() {

    return _buf_start;

  }

  // writing --

  // The path must not exist at run-time

  void add_nonexist_path(const char* path) {

    add_path(path, NON_EXIST);

  }

  // The path must exist, and must contain exactly <num_entries> files/dirs

  void add_boot_classpath(const char* path) {

    add_path(path, BOOT_PATH);

  }

  void add_app_classpath(const char* path) {

    add_path(path, APP_PATH);

  }

  void record_app_offset() {

    _app_offset = get_used_bytes();

  }

  void pop_app() {

    _cur_ptr = _buf_start + _app_offset;

    write_jint(0);

  }

  int write_jint(jint num) {

    write(&num, sizeof(num));

    return 0;

  }

  void write_time(time_t t) {

    write(&t, sizeof(t));

  }

  void write_long(long l) {

    write(&l, sizeof(l));

  }

  bool dump_to_file(int fd) {

    int n = get_used_bytes();

    return (os::write(fd, _buf_start, n) == (size_t)n);

  }

  // reading --

private:

  enum {

    BOOT_PATH      = 1,

    APP_PATH       = 2,

    NON_EXIST      = 3

  };

  const char* type_name(int type) {

    switch (type) {

    case BOOT_PATH:   return "BOOT";

    case APP_PATH:    return "APP";

    case NON_EXIST:   return "NON_EXIST";

    default:          ShouldNotReachHere(); return "?";

    }

  }

  void print_path(outputStream* os, int type, const char* path);

  bool read_jint(jint *ptr) {

    return read(ptr, sizeof(jint));

  }

  bool read_long(long *ptr) {

    return read(ptr, sizeof(long));

  }

  bool read_time(time_t *ptr) {

    return read(ptr, sizeof(time_t));

  }

public:

};

#endif // SHARE_CLASSFILE_SHAREDPATHSMISCINFO_HPP