1 files changed, 64 insertions, 0 deletions
diff --git a/widget/nsCUPSShim.cpp b/widget/nsCUPSShim.cpp
new file mode 100644
index 0000000000..1da189c725
--- /dev/null
+++ b/widget/nsCUPSShim.cpp
@@ -0,0 +1,64 @@
+/* -*- Mode: C; tab-width: 4; 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/. */
+
+#include "nsDebug.h"
+#include "nsString.h"
+#include "nsCUPSShim.h"
+#include "mozilla/ArrayUtils.h"
+#include "prlink.h"
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+
+// TODO: This is currently pointless as we always use the compile-time linked
+// version of CUPS, but in the future this may become a configure option.
+// We also cannot use NSPR's library suffix support, since that cannot handle
+// version number suffixes.
+#  ifdef XP_MACOSX
+static const char gCUPSLibraryName[] = "libcups.2.dylib";
+#  else
+static const char gCUPSLibraryName[] = "libcups.so.2";
+#  endif
+
+template <typename FuncT>
+static bool LoadCupsFunc(PRLibrary*& lib, FuncT*& dest,
+                         const char* const name) {
+  dest = (FuncT*)PR_FindSymbol(lib, name);
+  if (MOZ_UNLIKELY(!dest)) {
+#  ifdef DEBUG
+    nsAutoCString msg(name);
+    msg.AppendLiteral(" not found in CUPS library");
+    NS_WARNING(msg.get());
+#  endif
+#  ifndef MOZ_TSAN
+    // With TSan, we cannot unload libcups once we have loaded it because
+    // TSan does not support unloading libraries that are matched from its
+    // suppression list. Hence we just keep the library loaded in TSan builds.
+    PR_UnloadLibrary(lib);
+#  endif
+    lib = nullptr;
+    return false;
+  }
+  return true;
+}
+
+nsCUPSShim::nsCUPSShim() {
+  mCupsLib = PR_LoadLibrary(gCUPSLibraryName);
+  if (!mCupsLib) {
+    return;
+  }
+
+  // This is a macro so that it could also load from libcups if we are
+  // configured to use it as a compile-time dependency.
+#  define CUPS_SHIM_LOAD(NAME) \
+    if (!LoadCupsFunc(mCupsLib, NAME, #NAME)) return;
+  CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_LOAD)
+#  undef CUPS_SHIM_LOAD
+
+  // Set mInitOkay only if all cups functions are loaded successfully.
+  mInitOkay = true;
+}
+
+#endif