/*

 * Copyright (c) 2003, 2014, 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"

#include "memory/metaspace.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

//  read-only space

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

//  tag(666)

static const int JVM_IDENT_MAX = 256;

class Metaspace;

class SharedClassPathEntry VALUE_OBJ_CLASS_SPEC {

public:

  const char *_name;

  bool is_dir() {

    return _filesize == -1;

  }

};

class FileMapInfo : public CHeapObj<mtInternal> {

private:

  friend class ManifestStream;

  enum {

    _invalid_version = -1,

    _current_version = 2

  };

  bool  _file_open;

  int   _fd;

  size_t  _file_offset;

private:

  static SharedClassPathEntry* _classpath_entry_table;

  static int                   _classpath_entry_table_size;

  static size_t                _classpath_entry_size;

  static bool                  _validating_classpath_entry_table;

  // 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.

public:

  struct FileMapHeaderBase : public CHeapObj<mtClass> {

    virtual bool validate() = 0;

    virtual void populate(FileMapInfo* info, size_t alignment) = 0;

  };

  struct FileMapHeader : FileMapHeaderBase {

    // Use data() and data_size() to memcopy to/from the FileMapHeader. We need to

    // avoid read/writing the C++ vtable pointer.

    static size_t data_size();

    char* data() {

      return ((char*)this) + sizeof(FileMapHeaderBase);

    }

    int    _magic;                    // identify file type.

    int    _crc;                      // header crc checksum.

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

    size_t _alignment;                // how shared archive should be aligned

    int    _obj_alignment;            // value of ObjectAlignmentInBytes

    struct space_info {

      int    _crc;           // crc checksum of the current space

      size_t _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  _jvm_ident[JVM_IDENT_MAX];      // identifier for jvm

    // The _paths_misc_info is a variable-size structure that records "miscellaneous"

    // information during dumping. It is generated and validated by the

    // SharedPathsMiscInfo class. See SharedPathsMiscInfo.hpp and sharedClassUtil.hpp for

    // detailed description.

    //

    // The _paths_misc_info data is stored as a byte array in the archive file header,

    // immediately after the _header field. This information is used only when

    // checking the validity of the archive and is deallocated after the archive is loaded.

    //

    // Note that the _paths_misc_info does NOT include information for JAR files

    // that existed during dump time. Their information is stored in _classpath_entry_table.

    int _paths_misc_info_size;

    // The following is a table of all the class path entries that were used

    // during dumping. At run time, we require these files to exist and have the same

    // size/modification time, or else the archive will refuse to load.

    //

    // All of these entries must be JAR files. The dumping process would fail if a non-empty

    // directory was specified in the classpaths. If an empty directory was specified

    // it is checked by the _paths_misc_info as described above.

    //

    // FIXME -- if JAR files in the tail of the list were specified but not used during dumping,

    // they should be removed from this table, to save space and to avoid spurious

    // loading failures during runtime.

    int _classpath_entry_table_size;

    size_t _classpath_entry_size;

    SharedClassPathEntry* _classpath_entry_table;

    virtual bool validate();

    virtual void populate(FileMapInfo* info, size_t alignment);

    int compute_crc();

  };

  FileMapHeader * _header;

  const char* _full_path;

  char* _paths_misc_info;

  static FileMapInfo* _current_info;

  bool  init_from_file(int fd);

  void  align_file_position();

  bool  validate_header_impl();

public:

  FileMapInfo();

  ~FileMapInfo();

  static int current_version()        { return _current_version; }

  int    compute_header_crc()         { return _header->compute_crc(); }

  void   set_header_crc(int crc)      { _header->_crc = crc; }

  void   populate_header(size_t alignment);

  bool   validate_header();

  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 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);

  bool  verify_region_checksum(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, ...) ATTRIBUTE_PRINTF(1, 2);

  static void fail_continue(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);

  // 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;

  static size_t shared_spaces_size() {

    return align_size_up(SharedReadOnlySize + SharedReadWriteSize +

                         SharedMiscDataSize + SharedMiscCodeSize,

                         os::vm_allocation_granularity());

  }

  // Stop CDS sharing and unmap CDS regions.

  static void stop_sharing_and_unmap(const char* msg);

  static void allocate_classpath_entry_table();

  bool validate_classpath_entry_table();

  static SharedClassPathEntry* shared_classpath(int index) {

    char* p = (char*)_classpath_entry_table;

    p += _classpath_entry_size * index;

    return (SharedClassPathEntry*)p;

  }

  static const char* shared_classpath_name(int index) {

    return shared_classpath(index)->_name;

  }

  static int get_number_of_share_classpaths() {

    return _classpath_entry_table_size;

  }

};

#endif // SHARE_VM_MEMORY_FILEMAP_HPP