gecko-dev/dom/gamepad/linux/LinuxGamepad.cpp

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9.4 KiB
C++

/* -*- 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/. */
/*
* 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 <linux/joystick.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include "nscore.h"
#include "mozilla/dom/GamepadFunctions.h"
#include "udev.h"
namespace {
using namespace mozilla::dom::GamepadFunctions;
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");
if (!vendor_id || !model_id) {
struct udev_device* parent =
mUdev.udev_device_get_parent_with_subsystem_devtype(dev,
"input",
nullptr);
if (parent) {
vendor_id = mUdev.udev_device_get_sysattr_value(parent, "id/vendor");
model_id = mUdev.udev_device_get_sysattr_value(parent, "id/product");
}
}
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;
gamepad.index = AddGamepad(gamepad.idstring,
mozilla::dom::GamepadMappingType::_empty,
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;
}
for (unsigned int i = 0; i < mGamepads.Length(); i++) {
if (strcmp(mGamepads[i].devpath, devpath) == 0) {
g_source_remove(mGamepads[i].source_id);
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;
}
switch (event.type) {
case JS_EVENT_BUTTON:
NewButtonEvent(index, event.number, !!event.value);
break;
case JS_EVENT_AXIS:
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 dom {
void StartGamepadMonitoring()
{
if (gService) {
return;
}
gService = new LinuxGamepadService();
gService->Startup();
}
void StopGamepadMonitoring()
{
if (!gService) {
return;
}
gService->Shutdown();
delete gService;
gService = nullptr;
}
} // namespace dom
} // namespace mozilla