1 files changed, 150 insertions, 0 deletions
diff --git a/dom/gamepad/linux/udev.h b/dom/gamepad/linux/udev.h
new file mode 100644
index 0000000000..4e3f0b7865
--- /dev/null
+++ b/dom/gamepad/linux/udev.h
@@ -0,0 +1,150 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/*
+ * This file defines a wrapper around libudev so we can avoid
+ * linking directly to it and use dlopen instead.
+ */
+
+#ifndef HAL_LINUX_UDEV_H_
+#define HAL_LINUX_UDEV_H_
+
+#include <dlfcn.h>
+
+#include "mozilla/ArrayUtils.h"
+
+namespace mozilla {
+
+struct udev;
+struct udev_device;
+struct udev_enumerate;
+struct udev_list_entry;
+struct udev_monitor;
+
+class udev_lib {
+ public:
+  udev_lib() : lib(nullptr), udev(nullptr) {
+    // Be careful about ABI compat! 0 -> 1 didn't change any
+    // symbols this code relies on, per:
+    // https://lists.fedoraproject.org/pipermail/devel/2012-June/168227.html
+    const char* lib_names[] = {"libudev.so.0", "libudev.so.1"};
+    // Check whether a library is already loaded so we don't load two
+    // conflicting libs.
+    for (unsigned i = 0; i < ArrayLength(lib_names); i++) {
+      lib = dlopen(lib_names[i], RTLD_NOLOAD | RTLD_LAZY | RTLD_GLOBAL);
+      if (lib) {
+        break;
+      }
+    }
+    // If nothing loads the first time through, it means no version of libudev
+    // was already loaded.
+    if (!lib) {
+      for (unsigned i = 0; i < ArrayLength(lib_names); i++) {
+        lib = dlopen(lib_names[i], RTLD_LAZY | RTLD_GLOBAL);
+        if (lib) {
+          break;
+        }
+      }
+    }
+    if (lib && LoadSymbols()) {
+      udev = udev_new();
+    }
+  }
+
+  ~udev_lib() {
+    if (udev) {
+      udev_unref(udev);
+    }
+
+    if (lib) {
+      dlclose(lib);
+    }
+  }
+
+  explicit operator bool() { return udev; }
+
+ private:
+#define DLSYM(s)                       \
+  do {                                 \
+    (s) = (decltype(s))dlsym(lib, #s); \
+    if (!(s)) return false;            \
+  } while (0)
+
+  bool LoadSymbols() {
+    DLSYM(udev_new);
+    DLSYM(udev_unref);
+    DLSYM(udev_device_unref);
+    DLSYM(udev_device_new_from_syspath);
+    DLSYM(udev_device_get_devnode);
+    DLSYM(udev_device_get_parent_with_subsystem_devtype);
+    DLSYM(udev_device_get_property_value);
+    DLSYM(udev_device_get_action);
+    DLSYM(udev_device_get_sysattr_value);
+    DLSYM(udev_enumerate_new);
+    DLSYM(udev_enumerate_unref);
+    DLSYM(udev_enumerate_add_match_subsystem);
+    DLSYM(udev_enumerate_scan_devices);
+    DLSYM(udev_enumerate_get_list_entry);
+    DLSYM(udev_list_entry_get_next);
+    DLSYM(udev_list_entry_get_name);
+    DLSYM(udev_monitor_new_from_netlink);
+    DLSYM(udev_monitor_filter_add_match_subsystem_devtype);
+    DLSYM(udev_monitor_enable_receiving);
+    DLSYM(udev_monitor_get_fd);
+    DLSYM(udev_monitor_receive_device);
+    DLSYM(udev_monitor_unref);
+
+    return true;
+  }
+
+#undef DLSYM
+
+  void* lib;
+
+ public:
+  struct udev* udev;
+
+  // Function pointers returned from dlsym.
+  struct udev* (*udev_new)(void);
+  void (*udev_unref)(struct udev*);
+
+  void (*udev_device_unref)(struct udev_device*);
+  struct udev_device* (*udev_device_new_from_syspath)(struct udev*,
+                                                      const char*);
+  const char* (*udev_device_get_devnode)(struct udev_device*);
+  struct udev_device* (*udev_device_get_parent_with_subsystem_devtype)(
+      struct udev_device*, const char*, const char*);
+  const char* (*udev_device_get_property_value)(struct udev_device*,
+                                                const char*);
+  const char* (*udev_device_get_action)(struct udev_device*);
+  const char* (*udev_device_get_sysattr_value)(struct udev_device*,
+                                               const char*);
+
+  struct udev_enumerate* (*udev_enumerate_new)(struct udev*);
+  void (*udev_enumerate_unref)(struct udev_enumerate*);
+  int (*udev_enumerate_add_match_subsystem)(struct udev_enumerate*,
+                                            const char*);
+  int (*udev_enumerate_scan_devices)(struct udev_enumerate*);
+  struct udev_list_entry* (*udev_enumerate_get_list_entry)(
+      struct udev_enumerate*);
+
+  struct udev_list_entry* (*udev_list_entry_get_next)(struct udev_list_entry*);
+  const char* (*udev_list_entry_get_name)(struct udev_list_entry*);
+
+  struct udev_monitor* (*udev_monitor_new_from_netlink)(struct udev*,
+                                                        const char*);
+  int (*udev_monitor_filter_add_match_subsystem_devtype)(struct udev_monitor*,
+                                                         const char*,
+                                                         const char*);
+  int (*udev_monitor_enable_receiving)(struct udev_monitor*);
+  int (*udev_monitor_get_fd)(struct udev_monitor*);
+  struct udev_device* (*udev_monitor_receive_device)(struct udev_monitor*);
+  void (*udev_monitor_unref)(struct udev_monitor*);
+};
+
+}  // namespace mozilla
+
+#endif  // HAL_LINUX_UDEV_H_