src/ipc/mem/Page.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_IPC_MEM_PAGE_H
  10 #define SQUID_IPC_MEM_PAGE_H
  11
  12 #include <iosfwd>
  13
  14 namespace Ipc
  15 {
  16
  17 namespace Mem
  18 {
  19
  20 /// Shared memory page identifier, address, or handler
  21 class PageId
  22 {
  23 public:
  24     PageId(): pool(0), number(0), purpose(maxPurpose) {}
  25
  26     /// true if and only if both critical components have been initialized
  27     bool set() const { return pool && number; }
  28
  29     // safer than bool which would enable silent casts to int
  30     typedef const uint32_t PageId::*SaferBool;
  31     operator SaferBool() const { return set() ? &PageId::number : NULL; }
  32
  33     uint32_t pool; ///< page pool ID within Squid
  34     // uint32_t segment; ///< memory segment ID within the pool; unused for now
  35     uint32_t number; ///< page number within the segment
  36
  37     enum Purpose { cachePage, ioPage, maxPurpose };
  38     Purpose purpose; ///< page purpose
  39 };
  40
  41 /// writes page address (e.g., "sh_page5.3"), for debugging
  42 std::ostream &operator <<(std::ostream &os, const PageId &page);
  43
  44 } // namespace Mem
  45
  46 } // namespace Ipc
  47
  48 #endif // SQUID_IPC_MEM_PAGE_H
  49