widget/nsCUPSShim.h

   1 /* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ex: set tabstop=8 softtabstop=2 shiftwidth=2 expandtab: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsCUPSShim_h___
   8 #define nsCUPSShim_h___
   9
  10 #include <cups/cups.h>
  11 #include "mozilla/Atomics.h"
  12 #include "mozilla/Mutex.h"
  13
  14 // TODO: This should be a configure option, ideally.
  15 #ifndef XP_MACOSX
  16 #  define CUPS_SHIM_RUNTIME_LINK
  17 #endif
  18
  19 struct PRLibrary;
  20
  21 class nsCUPSShim {
  22  public:
  23 #ifdef CUPS_SHIM_RUNTIME_LINK
  24   nsCUPSShim();
  25   bool InitOkay() { return mInitOkay; }
  26 #else
  27   nsCUPSShim() = default;
  28   bool InitOkay() { return true; }
  29 #endif
  30
  31   // We allow some functions to be missing, to degrade as gracefully as possible
  32   // for older versions of CUPS.
  33   //
  34   // The current target is CUPS 1.6 (bug 1701019).
  35   enum class Optional : bool { No, Yes };
  36
  37   /**
  38    * Function pointers for supported functions. These are only
  39    * valid after successful initialization.
  40    */
  41 #define CUPS_SHIM_ALL_FUNCS(X)              \
  42   X(Optional::No, cupsAddOption)            \
  43   X(Optional::No, cupsCheckDestSupported)   \
  44   X(Optional::No, cupsConnectDest)          \
  45   X(Optional::No, cupsCopyDest)             \
  46   X(Optional::No, cupsCopyDestInfo)         \
  47   X(Optional::No, cupsDoRequest)            \
  48   X(Optional::No, cupsEnumDests)            \
  49   X(Optional::No, cupsFreeDestInfo)         \
  50   X(Optional::No, cupsFreeDests)            \
  51   X(Optional::No, cupsGetDestMediaByName)   \
  52   X(Optional::Yes, cupsFindDestDefault)     \
  53   X(Optional::Yes, cupsGetDestMediaDefault) \
  54   X(Optional::Yes, cupsGetDestMediaCount)   \
  55   X(Optional::Yes, cupsGetDestMediaByIndex) \
  56   X(Optional::Yes, cupsLocalizeDestMedia)   \
  57   X(Optional::No, cupsGetDest)              \
  58   X(Optional::No, cupsGetDests)             \
  59   X(Optional::No, cupsGetDests2)            \
  60   X(Optional::No, cupsGetNamedDest)         \
  61   X(Optional::No, cupsGetOption)            \
  62   X(Optional::No, cupsServer)               \
  63   X(Optional::Yes, httpAddrPort)            \
  64   X(Optional::No, httpClose)                \
  65   X(Optional::No, httpGetHostname)          \
  66   X(Optional::Yes, httpGetAddress)          \
  67   X(Optional::No, ippAddString)             \
  68   X(Optional::No, ippAddStrings)            \
  69   X(Optional::No, ippDelete)                \
  70   X(Optional::No, ippFindAttribute)         \
  71   X(Optional::No, ippGetCount)              \
  72   X(Optional::No, ippGetString)             \
  73   X(Optional::No, ippNewRequest)            \
  74   X(Optional::No, ippPort)
  75
  76 #ifdef CUPS_SHIM_RUNTIME_LINK
  77   // Define a single field which holds a function pointer.
  78 #  define CUPS_SHIM_FUNC_DECL(opt_, fn_) decltype(::fn_)* fn_ = nullptr;
  79 #else
  80   // Define a static constexpr function pointer. GCC can sometimes optimize
  81   // away the pointer fetch for this.
  82 #  define CUPS_SHIM_FUNC_DECL(opt_, fn_) \
  83     static constexpr decltype(::fn_)* const fn_ = ::fn_;
  84 #endif
  85
  86   CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_FUNC_DECL)
  87 #undef CUPS_SHIM_FUNC_DECL
  88
  89 #ifdef CUPS_SHIM_RUNTIME_LINK
  90  private:
  91   bool mInitOkay = false;
  92   PRLibrary* mCupsLib = nullptr;
  93 #endif
  94 };
  95
  96 #endif /* nsCUPSShim_h___ */