1 files changed, 96 insertions, 0 deletions
diff --git a/widget/nsCUPSShim.h b/widget/nsCUPSShim.h
new file mode 100644
index 0000000000..8ab00a48ad
--- /dev/null
+++ b/widget/nsCUPSShim.h
@@ -0,0 +1,96 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ex: set tabstop=8 softtabstop=2 shiftwidth=2 expandtab: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCUPSShim_h___
+#define nsCUPSShim_h___
+
+#include <cups/cups.h>
+#include "mozilla/Atomics.h"
+#include "mozilla/Mutex.h"
+
+// TODO: This should be a configure option, ideally.
+#ifndef XP_MACOSX
+#  define CUPS_SHIM_RUNTIME_LINK
+#endif
+
+struct PRLibrary;
+
+class nsCUPSShim {
+ public:
+#ifdef CUPS_SHIM_RUNTIME_LINK
+  nsCUPSShim();
+  bool InitOkay() { return mInitOkay; }
+#else
+  nsCUPSShim() = default;
+  bool InitOkay() { return true; }
+#endif
+
+  // We allow some functions to be missing, to degrade as gracefully as possible
+  // for older versions of CUPS.
+  //
+  // The current target is CUPS 1.6 (bug 1701019).
+  enum class Optional : bool { No, Yes };
+
+  /**
+   * Function pointers for supported functions. These are only
+   * valid after successful initialization.
+   */
+#define CUPS_SHIM_ALL_FUNCS(X)              \
+  X(Optional::No, cupsAddOption)            \
+  X(Optional::No, cupsCheckDestSupported)   \
+  X(Optional::No, cupsConnectDest)          \
+  X(Optional::No, cupsCopyDest)             \
+  X(Optional::No, cupsCopyDestInfo)         \
+  X(Optional::No, cupsDoRequest)            \
+  X(Optional::No, cupsEnumDests)            \
+  X(Optional::No, cupsFreeDestInfo)         \
+  X(Optional::No, cupsFreeDests)            \
+  X(Optional::No, cupsGetDestMediaByName)   \
+  X(Optional::Yes, cupsFindDestDefault)     \
+  X(Optional::Yes, cupsGetDestMediaDefault) \
+  X(Optional::Yes, cupsGetDestMediaCount)   \
+  X(Optional::Yes, cupsGetDestMediaByIndex) \
+  X(Optional::Yes, cupsLocalizeDestMedia)   \
+  X(Optional::No, cupsGetDest)              \
+  X(Optional::No, cupsGetDests)             \
+  X(Optional::No, cupsGetDests2)            \
+  X(Optional::No, cupsGetNamedDest)         \
+  X(Optional::No, cupsGetOption)            \
+  X(Optional::No, cupsServer)               \
+  X(Optional::Yes, httpAddrPort)            \
+  X(Optional::No, httpClose)                \
+  X(Optional::No, httpGetHostname)          \
+  X(Optional::Yes, httpGetAddress)          \
+  X(Optional::No, ippAddString)             \
+  X(Optional::No, ippAddStrings)            \
+  X(Optional::No, ippDelete)                \
+  X(Optional::No, ippFindAttribute)         \
+  X(Optional::No, ippGetCount)              \
+  X(Optional::No, ippGetString)             \
+  X(Optional::No, ippNewRequest)            \
+  X(Optional::No, ippPort)
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+  // Define a single field which holds a function pointer.
+#  define CUPS_SHIM_FUNC_DECL(opt_, fn_) decltype(::fn_)* fn_ = nullptr;
+#else
+  // Define a static constexpr function pointer. GCC can sometimes optimize
+  // away the pointer fetch for this.
+#  define CUPS_SHIM_FUNC_DECL(opt_, fn_) \
+    static constexpr decltype(::fn_)* const fn_ = ::fn_;
+#endif
+
+  CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_FUNC_DECL)
+#undef CUPS_SHIM_FUNC_DECL
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+ private:
+  bool mInitOkay = false;
+  PRLibrary* mCupsLib = nullptr;
+#endif
+};
+
+#endif /* nsCUPSShim_h___ */