/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ANDROID_INPUT_HUB_H_
#define ANDROID_INPUT_HUB_H_
#include <memory>
#include <string>
#include <unordered_map>
#include <utils/String8.h>
#include <utils/Timers.h>
namespace android {
/**
* InputEvent represents an event from the kernel. The fields largely mirror
* those found in linux/input.h.
*/
struct InputEvent {
nsecs_t when;
int32_t type;
int32_t code;
int32_t value;
};
/** Describes an absolute axis. */
struct AbsoluteAxisInfo {
int32_t minValue = 0; // minimum value
int32_t maxValue = 0; // maximum value
int32_t flat = 0; // center flat position, e.g. flat == 8 means center is between -8 and 8
int32_t fuzz = 0; // error tolerance, e.g. fuzz == 4 means value is +/- 4 due to noise
int32_t resolution = 0; // resolution in units per mm or radians per mm
};
/**
* An InputDeviceNode represents a device node in the Linux system. It can be
* used to interact with the device, setting and getting property values.
*
* An InputDeviceNode should only be used on the same thread that is polling for
* input events.
*/
class InputDeviceNode {
public:
virtual const std::string& getPath() const = 0;
virtual const std::string& getName() const = 0;
virtual const std::string& getLocation() const = 0;
virtual const std::string& getUniqueId() const = 0;
virtual uint16_t getBusType() const = 0;
virtual uint16_t getVendorId() const = 0;
virtual uint16_t getProductId() const = 0;
virtual uint16_t getVersion() const = 0;
virtual bool hasKey(int32_t key) const = 0;
virtual bool hasRelativeAxis(int axis) const = 0;
virtual const AbsoluteAxisInfo* getAbsoluteAxisInfo(int32_t axis) const = 0;
virtual bool hasInputProperty(int property) const = 0;
virtual int32_t getKeyState(int32_t key) const = 0;
virtual int32_t getSwitchState(int32_t sw) const = 0;
virtual status_t getAbsoluteAxisValue(int32_t axis, int32_t* outValue) const = 0;
virtual void vibrate(nsecs_t duration) = 0;
virtual void cancelVibrate(int32_t deviceId) = 0;
virtual void disableDriverKeyRepeat() = 0;
protected:
InputDeviceNode() = default;
virtual ~InputDeviceNode() = default;
};
/** Callback interface for receiving input events, including device changes. */
class InputCallbackInterface {
public:
virtual void onInputEvent(std::shared_ptr<InputDeviceNode> node, InputEvent& event,
nsecs_t event_time) = 0;
virtual void onDeviceAdded(std::shared_ptr<InputDeviceNode> node) = 0;
virtual void onDeviceRemoved(std::shared_ptr<InputDeviceNode> node) = 0;
protected:
InputCallbackInterface() = default;
virtual ~InputCallbackInterface() = default;
};
/**
* InputHubInterface is responsible for monitoring a set of device paths and
* executing callbacks when events occur. Before calling poll(), you should set
* the device and input callbacks, and register your device path(s).
*/
class InputHubInterface {
public:
virtual status_t registerDevicePath(const std::string& path) = 0;
virtual status_t unregisterDevicePath(const std::string& path) = 0;
virtual status_t poll() = 0;
virtual status_t wake() = 0;
virtual void dump(String8& dump) = 0;
protected:
InputHubInterface() = default;
virtual ~InputHubInterface() = default;
};
/**
* An implementation of InputHubInterface that uses epoll to wait for events.
*
* This class is not threadsafe. Any functions called on the InputHub should be
* called on the same thread that is used to call poll(). The only exception is
* wake(), which may be used to return from poll() before an input or device
* event occurs.
*/
class InputHub : public InputHubInterface {
public:
explicit InputHub(std::shared_ptr<InputCallbackInterface> cb);
virtual ~InputHub() override;
virtual status_t registerDevicePath(const std::string& path) override;
virtual status_t unregisterDevicePath(const std::string& path) override;
virtual status_t poll() override;
virtual status_t wake() override;
virtual void dump(String8& dump) override;
private:
status_t readNotify();
status_t scanDir(const std::string& path);
status_t openNode(const std::string& path, std::shared_ptr<InputDeviceNode>* outNode);
status_t closeNode(const std::shared_ptr<InputDeviceNode>& node);
status_t closeNodeByFd(int fd);
std::shared_ptr<InputDeviceNode> findNodeByPath(const std::string& path);
enum class WakeMechanism {
/**
* The kernel supports the EPOLLWAKEUP flag for epoll_ctl.
*
* When using this mechanism, epoll_wait will internally acquire a wake
* lock whenever one of the FDs it is monitoring becomes ready. The wake
* lock is held automatically by the kernel until the next call to
* epoll_wait.
*
* This mechanism only exists in Linux kernel 3.5+.
*/
EPOLL_WAKEUP,
/**
* The kernel evdev driver supports the EVIOCSSUSPENDBLOCK ioctl.
*
* When using this mechanism, the InputHub asks evdev to acquire and
* hold a wake lock whenever its buffer is non-empty. We must take care
* to acquire our own userspace wake lock before draining the buffer to
* prevent actually going back into suspend before we have fully
* processed all of the events.
*
* This mechanism only exists in older Android Linux kernels.
*/
LEGACY_EVDEV_SUSPENDBLOCK_IOCTL,
/**
* The kernel doesn't seem to support any special wake mechanism.
*
* We explicitly acquire and release wake locks when processing input
* events.
*/
LEGACY_EVDEV_EXPLICIT_WAKE_LOCKS,
};
WakeMechanism mWakeupMechanism = WakeMechanism::LEGACY_EVDEV_EXPLICIT_WAKE_LOCKS;
bool manageWakeLocks() const;
bool mNeedToCheckSuspendBlockIoctl = true;
int mEpollFd;
int mINotifyFd;
int mWakeEventFd;
int mWakeReadPipeFd;
int mWakeWritePipeFd;
// Callback for input events
std::shared_ptr<InputCallbackInterface> mInputCallback;
// Map from watch descriptors to watched paths
std::unordered_map<int, std::string> mWatchedPaths;
// Map from file descriptors to InputDeviceNodes
std::unordered_map<int, std::shared_ptr<InputDeviceNode>> mDeviceNodes;
};
} // namespace android
#endif // ANDROID_INPUT_HUB_H_