1 files changed, 66 insertions, 0 deletions
diff --git a/third_party/drm/libdrm/mozdrm.cpp b/third_party/drm/libdrm/mozdrm.cpp
new file mode 100644
index 0000000000..b2fb59be64
--- /dev/null
+++ b/third_party/drm/libdrm/mozdrm.cpp
@@ -0,0 +1,66 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* 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 "mozilla/Types.h"
+#include "prlink.h"
+
+#include <drm/xf86drm.h>
+
+#define GET_FUNC(func, lib)                                  \
+    func##_fn =                                              \
+      (decltype(func##_fn))PR_FindFunctionSymbol(lib, #func) \
+
+#define IS_FUNC_LOADED(func)                                          \
+    (func != nullptr)                                                 \
+
+static int (*drmGetDevices2_fn)(uint32_t flags, drmDevicePtr devices[], int max_devices);
+static void (*drmFreeDevices_fn)(drmDevicePtr devices[], int count);
+
+bool IsDRMLibraryLoaded() {
+  static bool isLoaded =
+         (IS_FUNC_LOADED(drmGetDevices2_fn) &&
+          IS_FUNC_LOADED(drmFreeDevices_fn));
+
+  return isLoaded;
+}
+
+bool LoadDRMLibrary() {
+  static PRLibrary* drmLib = nullptr;
+  static bool drmInitialized = false;
+
+  //TODO Thread safe
+  if (!drmInitialized) {
+    drmInitialized = true;
+    drmLib = PR_LoadLibrary("libdrm.so.2");
+    if (!drmLib) {
+      return false;
+    }
+
+    GET_FUNC(drmGetDevices2, drmLib);
+    GET_FUNC(drmFreeDevices, drmLib);
+  }
+
+  return IsDRMLibraryLoaded();
+}
+
+int
+drmGetDevices2(uint32_t flags, drmDevicePtr devices[], int max_devices)
+{
+  if (!LoadDRMLibrary()) {
+    return 0;
+  }
+  return drmGetDevices2_fn(flags, devices, max_devices);
+}
+
+void
+drmFreeDevices(drmDevicePtr devices[], int count)
+{
+  if (!LoadDRMLibrary()) {
+    return;
+  }
+  return drmFreeDevices_fn(devices, count);
+}