1 files changed, 76 insertions, 0 deletions
diff --git a/widget/nsCUPSShim.cpp b/widget/nsCUPSShim.cpp
new file mode 100644
index 0000000000..d999a1be17
--- /dev/null
+++ b/widget/nsCUPSShim.cpp
@@ -0,0 +1,76 @@
+/* -*- 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 "mozilla/Logging.h"
+#include "prlink.h"
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+
+mozilla::LazyLogModule gCupsLinkLog("CupsLink");
+
+#  define DEBUG_LOG(...) \
+    MOZ_LOG(gCupsLinkLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+
+// 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
+
+static bool LoadCupsFunc(PRLibrary* aLib, void** aDest, const char* const aName,
+                         nsCUPSShim::Optional aOptional) {
+  *aDest = PR_FindSymbol(aLib, aName);
+  if (!*aDest) {
+    DEBUG_LOG("%s not found in CUPS library", aName);
+    return bool(aOptional);
+  }
+  return true;
+}
+
+nsCUPSShim::nsCUPSShim() {
+  mCupsLib = PR_LoadLibrary(gCUPSLibraryName);
+  if (!mCupsLib) {
+    DEBUG_LOG("CUPS library not found");
+    return;
+  }
+
+  bool success = true;
+
+  // This is a macro so that it could also load from libcups if we are
+  // configured to use it as a compile-time dependency.
+  //
+  // We try to load all functions even if some fail so that we get the debug log
+  // unconditionally.
+#  define CUPS_SHIM_LOAD(opt_, fn_) \
+    success |=                      \
+        LoadCupsFunc(mCupsLib, reinterpret_cast<void**>(&fn_), #fn_, opt_);
+  CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_LOAD)
+#  undef CUPS_SHIM_LOAD
+
+  if (!success) {
+#  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(mCupsLib);
+#  endif
+    mCupsLib = nullptr;
+    return;
+  }
+
+  // Set mInitOkay only if all cups functions are loaded successfully.
+  mInitOkay = true;
+}
+
+#endif