bug 604039 - Linux gamepad backend. r=karlt

--HG--
extra : rebase_source : 32d47af727b9a6209d321a8622a2f3ecb7a44d25

configure.in

@@ -5968,6 +5968,13 @@ if test "$MOZ_GAMEPAD"; then
         fi
         MOZ_GAMEPAD_BACKEND=windows
         ;;
+    Linux)
+        MOZ_CHECK_HEADER([linux/joystick.h])
+        if test "$ac_cv_header_linux_joystick_h" != "yes"; then
+          AC_MSG_ERROR([Can't find header linux/joystick.h, needed for gamepad support. Please install Linux kernel headers or reconfigure with --disable-gamepad to disable gamepad support.])
+        fi
+        MOZ_GAMEPAD_BACKEND=linux
+        ;;
     *)
         ;;
    esac

hal/Makefile.in

@@ -51,6 +51,9 @@ endif
 ifeq (windows,$(MOZ_GAMEPAD_BACKEND))
 CPPSRCS += WindowsGamepad.cpp
 endif
+ifeq (linux,$(MOZ_GAMEPAD_BACKEND))
+CPPSRCS += LinuxGamepad.cpp
+endif
 
 ifeq (android,$(MOZ_WIDGET_TOOLKIT))
 CPPSRCS += \

hal/linux/LinuxGamepad.cpp

@@ -0,0 +1,364 @@
+/* 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/. */
+
+/*
+ * LinuxGamepadService: A Linux backend for the GamepadService.
+ * Derived from the kernel documentation at
+ * http://www.kernel.org/doc/Documentation/input/joystick-api.txt
+ */
+#include <algorithm>
+#include <cstddef>
+
+#include <glib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "nscore.h"
+#include "mozilla/dom/GamepadService.h"
+#include "udev.h"
+
+// Include this later because it also does #define JS_VERSION
+#include <linux/joystick.h>
+
+namespace {
+
+using mozilla::dom::GamepadService;
+using mozilla::udev_lib;
+using mozilla::udev_device;
+using mozilla::udev_list_entry;
+using mozilla::udev_enumerate;
+using mozilla::udev_monitor;
+
+static const float kMaxAxisValue = 32767.0;
+static const char kJoystickPath[] = "/dev/input/js";
+
+//TODO: should find a USB identifier for each device so we can
+// provide something that persists across connect/disconnect cycles.
+typedef struct {
+  int index;
+  guint source_id;
+  int numAxes;
+  int numButtons;
+  char idstring[128];
+  char devpath[PATH_MAX];
+} Gamepad;
+
+class LinuxGamepadService {
+public:
+  LinuxGamepadService() : mMonitor(nullptr),
+                          mMonitorSourceID(0) {
+  }
+
+  void Startup();
+  void Shutdown();
+
+private:
+  void AddDevice(struct udev_device* dev);
+  void RemoveDevice(struct udev_device* dev);
+  void ScanForDevices();
+  void AddMonitor();
+  void RemoveMonitor();
+  bool is_gamepad(struct udev_device* dev);
+  void ReadUdevChange();
+
+  // handler for data from /dev/input/jsN
+  static gboolean OnGamepadData(GIOChannel *source,
+                                GIOCondition condition,
+                                gpointer data);
+
+  // handler for data from udev monitor
+  static gboolean OnUdevMonitor(GIOChannel *source,
+                                GIOCondition condition,
+                                gpointer data);
+
+  udev_lib mUdev;
+  struct udev_monitor* mMonitor;
+  guint mMonitorSourceID;
+  // Information about currently connected gamepads.
+  nsAutoTArray<Gamepad,4> mGamepads;
+};
+
+// singleton instance
+LinuxGamepadService* gService = nullptr;
+
+void
+LinuxGamepadService::AddDevice(struct udev_device* dev)
+{
+  const char* devpath = mUdev.udev_device_get_devnode(dev);
+  if (!devpath) {
+    return;
+  }
+
+  // Ensure that this device hasn't already been added.
+  for (unsigned int i = 0; i < mGamepads.Length(); i++) {
+    if (strcmp(mGamepads[i].devpath, devpath) == 0) {
+      return;
+    }
+  }
+
+  Gamepad gamepad;
+  snprintf(gamepad.devpath, sizeof(gamepad.devpath), "%s", devpath);
+  GIOChannel* channel = g_io_channel_new_file(devpath, "r", nullptr);
+  if (!channel) {
+    return;
+  }
+
+  g_io_channel_set_flags(channel, G_IO_FLAG_NONBLOCK, nullptr);
+  g_io_channel_set_encoding(channel, nullptr, nullptr);
+  g_io_channel_set_buffered(channel, FALSE);
+  int fd = g_io_channel_unix_get_fd(channel);
+  char name[128];
+  if (ioctl(fd, JSIOCGNAME(sizeof(name)), &name) == -1) {
+    strcpy(name, "unknown");
+  }
+  const char* vendor_id =
+    mUdev.udev_device_get_property_value(dev, "ID_VENDOR_ID");
+  const char* model_id =
+    mUdev.udev_device_get_property_value(dev, "ID_MODEL_ID");
+  snprintf(gamepad.idstring, sizeof(gamepad.idstring),
+           "%s-%s-%s",
+           vendor_id ? vendor_id : "unknown",
+           model_id ? model_id : "unknown",
+           name);
+
+  char numAxes = 0, numButtons = 0;
+  ioctl(fd, JSIOCGAXES, &numAxes);
+  gamepad.numAxes = numAxes;
+  ioctl(fd, JSIOCGBUTTONS, &numButtons);
+  gamepad.numButtons = numButtons;
+
+  nsRefPtr<GamepadService> service(GamepadService::GetService());
+  gamepad.index = service->AddGamepad(gamepad.idstring,
+                                      gamepad.numButtons,
+                                      gamepad.numAxes);
+
+  gamepad.source_id =
+    g_io_add_watch(channel,
+                   GIOCondition(G_IO_IN | G_IO_ERR | G_IO_HUP),
+                   OnGamepadData,
+                   GINT_TO_POINTER(gamepad.index));
+  g_io_channel_unref(channel);
+
+  mGamepads.AppendElement(gamepad);
+}
+
+void
+LinuxGamepadService::RemoveDevice(struct udev_device* dev)
+{
+  const char* devpath = mUdev.udev_device_get_devnode(dev);
+  if (!devpath) {
+    return;
+  }
+
+  nsRefPtr<GamepadService> service(GamepadService::GetService());
+  for (unsigned int i = 0; i < mGamepads.Length(); i++) {
+    if (strcmp(mGamepads[i].devpath, devpath) == 0) {
+      g_source_remove(mGamepads[i].source_id);
+      service->RemoveGamepad(mGamepads[i].index);
+      mGamepads.RemoveElementAt(i);
+      break;
+    }
+  }
+}
+
+void
+LinuxGamepadService::ScanForDevices()
+{
+  struct udev_enumerate* en = mUdev.udev_enumerate_new(mUdev.udev);
+  mUdev.udev_enumerate_add_match_subsystem(en, "input");
+  mUdev.udev_enumerate_scan_devices(en);
+
+  struct udev_list_entry* dev_list_entry;
+  for (dev_list_entry = mUdev.udev_enumerate_get_list_entry(en);
+       dev_list_entry != nullptr;
+       dev_list_entry = mUdev.udev_list_entry_get_next(dev_list_entry)) {
+    const char* path = mUdev.udev_list_entry_get_name(dev_list_entry);
+    struct udev_device* dev = mUdev.udev_device_new_from_syspath(mUdev.udev,
+                                                                 path);
+    if (is_gamepad(dev)) {
+      AddDevice(dev);
+    }
+
+    mUdev.udev_device_unref(dev);
+  }
+
+  mUdev.udev_enumerate_unref(en);
+}
+
+void
+LinuxGamepadService::AddMonitor()
+{
+  // Add a monitor to watch for device changes
+  mMonitor =
+    mUdev.udev_monitor_new_from_netlink(mUdev.udev, "udev");
+  if (!mMonitor) {
+    // Not much we can do here.
+    return;
+  }
+  mUdev.udev_monitor_filter_add_match_subsystem_devtype(mMonitor,
+                                                        "input",
+							nullptr);
+
+  int monitor_fd = mUdev.udev_monitor_get_fd(mMonitor);
+  GIOChannel* monitor_channel = g_io_channel_unix_new(monitor_fd);
+  mMonitorSourceID =
+    g_io_add_watch(monitor_channel,
+                   GIOCondition(G_IO_IN | G_IO_ERR | G_IO_HUP),
+                   OnUdevMonitor,
+                   nullptr);
+  g_io_channel_unref(monitor_channel);
+
+  mUdev.udev_monitor_enable_receiving(mMonitor);
+}
+
+void
+LinuxGamepadService::RemoveMonitor()
+{
+  if (mMonitorSourceID) {
+    g_source_remove(mMonitorSourceID);
+    mMonitorSourceID = 0;
+  }
+  if (mMonitor) {
+    mUdev.udev_monitor_unref(mMonitor);
+    mMonitor = nullptr;
+  }
+}
+
+void
+LinuxGamepadService::Startup()
+{
+  // Don't bother starting up if libudev couldn't be loaded or initialized.
+  if (!mUdev)
+    return;
+
+  AddMonitor();
+  ScanForDevices();
+}
+
+void
+LinuxGamepadService::Shutdown()
+{
+  for (unsigned int i = 0; i < mGamepads.Length(); i++) {
+    g_source_remove(mGamepads[i].source_id);
+  }
+  mGamepads.Clear();
+  RemoveMonitor();
+}
+
+bool
+LinuxGamepadService::is_gamepad(struct udev_device* dev)
+{
+  if (!mUdev.udev_device_get_property_value(dev, "ID_INPUT_JOYSTICK"))
+    return false;
+
+  const char* devpath = mUdev.udev_device_get_devnode(dev);
+  if (!devpath) {
+    return false;
+  }
+  if (strncmp(kJoystickPath, devpath, sizeof(kJoystickPath) - 1) != 0) {
+    return false;
+  }
+
+  return true;
+}
+
+void
+LinuxGamepadService::ReadUdevChange()
+{
+  struct udev_device* dev =
+    mUdev.udev_monitor_receive_device(mMonitor);
+  const char* action = mUdev.udev_device_get_action(dev);
+  if (is_gamepad(dev)) {
+    if (strcmp(action, "add") == 0) {
+      AddDevice(dev);
+    } else if (strcmp(action, "remove") == 0) {
+      RemoveDevice(dev);
+    }
+  }
+  mUdev.udev_device_unref(dev);
+}
+
+// static
+gboolean
+LinuxGamepadService::OnGamepadData(GIOChannel* source,
+                                   GIOCondition condition,
+                                   gpointer data)
+{
+  int index = GPOINTER_TO_INT(data);
+  //TODO: remove gamepad?
+  if (condition & G_IO_ERR || condition & G_IO_HUP)
+    return FALSE;
+
+  while (true) {
+    struct js_event event;
+    gsize count;
+    GError* err = nullptr;
+    if (g_io_channel_read_chars(source,
+				(gchar*)&event,
+				sizeof(event),
+				&count,
+				&err) != G_IO_STATUS_NORMAL ||
+	count == 0) {
+      break;
+    }
+
+    //TODO: store device state?
+    if (event.type & JS_EVENT_INIT) {
+      continue;
+    }
+
+    nsRefPtr<GamepadService> service(GamepadService::GetService());
+    switch (event.type) {
+    case JS_EVENT_BUTTON:
+      service->NewButtonEvent(index, event.number, !!event.value);
+      break;
+    case JS_EVENT_AXIS:
+      service->NewAxisMoveEvent(index, event.number,
+                                ((float)event.value) / kMaxAxisValue);
+      break;
+    }
+  }
+
+  return TRUE;
+}
+
+// static
+gboolean
+LinuxGamepadService::OnUdevMonitor(GIOChannel* source,
+                                   GIOCondition condition,
+                                   gpointer data)
+{
+  if (condition & G_IO_ERR || condition & G_IO_HUP)
+    return FALSE;
+
+  gService->ReadUdevChange();
+  return TRUE;
+}
+
+} // namespace
+
+namespace mozilla {
+namespace hal_impl {
+
+void StartMonitoringGamepadStatus()
+{
+  if (!gService) {
+    gService = new LinuxGamepadService();
+    gService->Startup();
+  }
+}
+
+void StopMonitoringGamepadStatus()
+{
+  if (gService) {
+    gService->Shutdown();
+    delete gService;
+    gService = nullptr;
+  }
+}
+
+} // namespace hal_impl
+} // namespace mozilla

hal/linux/udev.h

@@ -0,0 +1,117 @@
+/* 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>
+
+namespace mozilla {
+
+struct udev;
+struct udev_device;
+struct udev_enumerate;
+struct udev_list_entry;
+struct udev_monitor;
+
+class udev_lib {
+ public:
+  udev_lib() : lib(dlopen("libudev.so.0", RTLD_LAZY | RTLD_GLOBAL)),
+               udev(NULL) {
+    if (lib && LoadSymbols())
+      udev = udev_new();
+  }
+
+  ~udev_lib() {
+    if (udev) {
+      udev_unref(udev);
+    }
+
+    if (lib) {
+      dlclose(lib);
+    }
+  }
+
+  operator bool() {
+    return udev;
+  }
+
+ private:
+  bool LoadSymbols() {
+#define DLSYM(s) \
+  do { \
+    s = (typeof(s))dlsym(lib, #s); \
+    if (!s) return false; \
+  } while (0)
+
+    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_property_value);
+    DLSYM(udev_device_get_action);
+    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);
+#undef DLSYM
+    return true;
+  }
+
+  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*);
+  const char* (*udev_device_get_property_value)(struct udev_device*,
+                                                const char*);
+  const char* (*udev_device_get_action)(struct udev_device*);
+
+  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_