/*

 * Copyright (c) 2003, 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_MEMORY_FILEMAP_HPP

#define SHARE_VM_MEMORY_FILEMAP_HPP

#include "memory/metaspaceShared.hpp"

// Layout of the file:

//  header: dump of archive instance plus versioning info, datestamp, etc.

//   [magic # = 0xF00BABA2]

//  ... padding to align on page-boundary

//  read-write space from CompactingPermGenGen

//  read-only space from CompactingPermGenGen

//  misc data (block offset table, string table, symbols, dictionary, etc.)

//  tag(666)

static const int JVM_SHARED_JARS_MAX = 128;

static const int JVM_SPACENAME_MAX = 128;

static const int JVM_IDENT_MAX = 256;

static const int JVM_ARCH_MAX = 12;

class Metaspace;

class FileMapInfo : public CHeapObj<mtInternal> {

private:

  enum {

    _invalid_version = -1,

    _current_version = 1

  };

  bool  _file_open;

  int   _fd;

  long  _file_offset;

  // FileMapHeader describes the shared space data in the file to be

  // mapped.  This structure gets written to a file.  It is not a class, so

  // that the compilers don't add any compiler-private data to it.

  struct FileMapHeader {

    int    _magic;                    // identify file type.

    int    _version;                  // (from enum, above.)

    size_t _alignment;                // how shared archive should be aligned

    int    _obj_alignment;            // value of ObjectAlignmentInBytes

    struct space_info {

      int    _file_offset;   // sizeof(this) rounded to vm page size

      char*  _base;          // copy-on-write base address

      size_t _capacity;      // for validity checking

      size_t _used;          // for setting space top on read

      bool   _read_only;     // read only space?

      bool   _allow_exec;    // executable code in space?

    } _space[MetaspaceShared::n_regions];

    // The following fields are all sanity checks for whether this archive

    // will function correctly with this JVM and the bootclasspath it's

    // invoked with.

    char  _arch[JVM_ARCH_MAX];            // architecture

    char  _jvm_ident[JVM_IDENT_MAX];      // identifier for jvm

    int   _num_jars;              // Number of jars in bootclasspath

    // Per jar file data:  timestamp, size.

    struct {

      time_t _timestamp;          // jar timestamp.

      long   _filesize;           // jar file size.

    } _jar[JVM_SHARED_JARS_MAX];

  } _header;

  const char* _full_path;

  static FileMapInfo* _current_info;

  bool  init_from_file(int fd);

  void  align_file_position();

public:

  FileMapInfo() {

    _file_offset = 0;

    _file_open = false;

    _header._version = _invalid_version;

  }

  static int current_version()        { return _current_version; }

  void   populate_header(size_t alignment);

  bool   validate();

  void   invalidate();

  int    version()                    { return _header._version; }

  size_t alignment()                  { return _header._alignment; }

  size_t space_capacity(int i)        { return _header._space[i]._capacity; }

  char*  region_base(int i)           { return _header._space[i]._base; }

  struct FileMapHeader* header()      { return &_header; }

  static void set_current_info(FileMapInfo* info) {

    CDS_ONLY(_current_info = info;)

  }

  static FileMapInfo* current_info() {

    CDS_ONLY(return _current_info;)

    NOT_CDS(return NULL;)

  }

  static void assert_mark(bool check);

  // File manipulation.

  bool  initialize() NOT_CDS_RETURN_(false);

  bool  open_for_read();

  void  open_for_write();

  void  write_header();

  void  write_space(int i, Metaspace* space, bool read_only);

  void  write_region(int region, char* base, size_t size,

                     size_t capacity, bool read_only, bool allow_exec);

  void  write_bytes(const void* buffer, int count);

  void  write_bytes_aligned(const void* buffer, int count);

  char* map_region(int i);

  void  unmap_region(int i);

  void  close();

  bool  is_open() { return _file_open; }

  ReservedSpace reserve_shared_memory();

  // JVM/TI RedefineClasses() support:

  // Remap the shared readonly space to shared readwrite, private.

  bool  remap_shared_readonly_as_readwrite();

  // Errors.

  static void fail_stop(const char *msg, ...);

  void fail_continue(const char *msg, ...);

  // Return true if given address is in the mapped shared space.

  bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);

  void print_shared_spaces() NOT_CDS_RETURN;

};

#endif // SHARE_VM_MEMORY_FILEMAP_HPP