services/inputflinger/PointerChoreographer.h

/*
 * Copyright 2023 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.
 */

#pragma once

#include "InputListener.h"
#include "NotifyArgs.h"
#include "PointerChoreographerPolicyInterface.h"

#include <android-base/thread_annotations.h>
#include <gui/WindowInfosListener.h>
#include <type_traits>
#include <unordered_set>

namespace android {

struct SpriteIcon;

/**
 * A helper class that wraps a factory method that acts as a constructor for the type returned
 * by the factory method.
 */
template <typename Factory>
struct ConstructorDelegate {
    constexpr ConstructorDelegate(Factory&& factory) : mFactory(std::move(factory)) {}

    using ConstructedType = std::invoke_result_t<const Factory&>;
    constexpr operator ConstructedType() const { return mFactory(); }

    Factory mFactory;
};

/**
 * PointerChoreographer manages the icons shown by the system for input interactions.
 * This includes showing the mouse cursor, stylus hover icons, and touch spots.
 * It is responsible for accumulating the location of the mouse cursor, and populating
 * the cursor position for incoming events, if necessary.
 */
class PointerChoreographerInterface : public InputListenerInterface {
public:
    /**
     * Set the display that pointers, like the mouse cursor and drawing tablets,
     * should be drawn on.
     */
    virtual void setDefaultMouseDisplayId(ui::LogicalDisplayId displayId) = 0;
    virtual void setDisplayViewports(const std::vector<DisplayViewport>& viewports) = 0;
    virtual std::optional<DisplayViewport> getViewportForPointerDevice(
            ui::LogicalDisplayId associatedDisplayId = ui::LogicalDisplayId::INVALID) = 0;
    virtual FloatPoint getMouseCursorPosition(ui::LogicalDisplayId displayId) = 0;
    virtual void setShowTouchesEnabled(bool enabled) = 0;
    virtual void setStylusPointerIconEnabled(bool enabled) = 0;
    /**
     * Set the icon that is shown for the given pointer. The request may fail in some cases, such
     * as if the device or display was removed, or if the cursor was moved to a different display.
     * Returns true if the icon was changed successfully, false otherwise.
     */
    virtual bool setPointerIcon(std::variant<std::unique_ptr<SpriteIcon>, PointerIconStyle> icon,
                                ui::LogicalDisplayId displayId, DeviceId deviceId) = 0;
    /**
     * Set whether pointer icons for mice, touchpads, and styluses should be visible on the
     * given display.
     */
    virtual void setPointerIconVisibility(ui::LogicalDisplayId displayId, bool visible) = 0;

    /**
     * Used by Dispatcher to notify changes in the current focused display.
     */
    virtual void setFocusedDisplay(ui::LogicalDisplayId displayId) = 0;

    /**
     * This method may be called on any thread (usually by the input manager on a binder thread).
     */
    virtual void dump(std::string& dump) = 0;
};

class PointerChoreographer : public PointerChoreographerInterface {
public:
    explicit PointerChoreographer(InputListenerInterface& listener,
                                  PointerChoreographerPolicyInterface&);
    ~PointerChoreographer() override;

    void setDefaultMouseDisplayId(ui::LogicalDisplayId displayId) override;
    void setDisplayViewports(const std::vector<DisplayViewport>& viewports) override;
    std::optional<DisplayViewport> getViewportForPointerDevice(
            ui::LogicalDisplayId associatedDisplayId) override;
    FloatPoint getMouseCursorPosition(ui::LogicalDisplayId displayId) override;
    void setShowTouchesEnabled(bool enabled) override;
    void setStylusPointerIconEnabled(bool enabled) override;
    bool setPointerIcon(std::variant<std::unique_ptr<SpriteIcon>, PointerIconStyle> icon,
                        ui::LogicalDisplayId displayId, DeviceId deviceId) override;
    void setPointerIconVisibility(ui::LogicalDisplayId displayId, bool visible) override;
    void setFocusedDisplay(ui::LogicalDisplayId displayId) override;

    void notifyInputDevicesChanged(const NotifyInputDevicesChangedArgs& args) override;
    void notifyKey(const NotifyKeyArgs& args) override;
    void notifyMotion(const NotifyMotionArgs& args) override;
    void notifySwitch(const NotifySwitchArgs& args) override;
    void notifySensor(const NotifySensorArgs& args) override;
    void notifyVibratorState(const NotifyVibratorStateArgs& args) override;
    void notifyDeviceReset(const NotifyDeviceResetArgs& args) override;
    void notifyPointerCaptureChanged(const NotifyPointerCaptureChangedArgs& args) override;

    // TODO(b/362719483) remove these when real topology is available
    enum class DisplayPosition {
        RIGHT,
        TOP,
        LEFT,
        BOTTOM,
        ftl_last = BOTTOM,
    };

    struct AdjacentDisplay {
        ui::LogicalDisplayId displayId;
        DisplayPosition position;
        float offsetPx;
    };
    void setDisplayTopology(
            const std::unordered_map<ui::LogicalDisplayId, std::vector<AdjacentDisplay>>&
                    displayTopology);

    void dump(std::string& dump) override;

private:
    using PointerDisplayChange = std::optional<
            std::tuple<ui::LogicalDisplayId /*displayId*/, FloatPoint /*cursorPosition*/>>;

    // PointerChoreographer's DisplayInfoListener can outlive the PointerChoreographer because when
    // the listener is registered and called from display thread, a strong pointer to the listener
    // (which can extend its lifecycle) is given away.
    // If we use two locks it can also cause deadlocks due to race in acquiring them between the
    // display and reader thread.
    // To avoid these problems we use DisplayInfoListener's lock in PointerChoreographer.
    std::mutex& getLock() const;

    [[nodiscard]] PointerDisplayChange updatePointerControllersLocked() REQUIRES(getLock());
    [[nodiscard]] PointerDisplayChange calculatePointerDisplayChangeToNotify() REQUIRES(getLock());
    const DisplayViewport* findViewportByIdLocked(ui::LogicalDisplayId displayId) const
            REQUIRES(getLock());
    ui::LogicalDisplayId getTargetMouseDisplayLocked(ui::LogicalDisplayId associatedDisplayId) const
            REQUIRES(getLock());
    std::pair<ui::LogicalDisplayId /*displayId*/, PointerControllerInterface&>
    ensureMouseControllerLocked(ui::LogicalDisplayId associatedDisplayId) REQUIRES(getLock());
    InputDeviceInfo* findInputDeviceLocked(DeviceId deviceId) REQUIRES(getLock());
    bool canUnfadeOnDisplay(ui::LogicalDisplayId displayId) REQUIRES(getLock());

    void fadeMouseCursorOnKeyPress(const NotifyKeyArgs& args);
    NotifyMotionArgs processMotion(const NotifyMotionArgs& args);
    NotifyMotionArgs processMouseEventLocked(const NotifyMotionArgs& args) REQUIRES(getLock());
    NotifyMotionArgs processTouchpadEventLocked(const NotifyMotionArgs& args) REQUIRES(getLock());
    void processDrawingTabletEventLocked(const NotifyMotionArgs& args) REQUIRES(getLock());
    void processTouchscreenAndStylusEventLocked(const NotifyMotionArgs& args) REQUIRES(getLock());
    void processStylusHoverEventLocked(const NotifyMotionArgs& args) REQUIRES(getLock());
    void processPointerDeviceMotionEventLocked(NotifyMotionArgs& newArgs,
                                               PointerControllerInterface& pc) REQUIRES(getLock());
    void processDeviceReset(const NotifyDeviceResetArgs& args);
    void onControllerAddedOrRemovedLocked() REQUIRES(getLock());
    void onPrivacySensitiveDisplaysChangedLocked(
            const std::unordered_set<ui::LogicalDisplayId>& privacySensitiveDisplays)
            REQUIRES(getLock());

    void handleUnconsumedDeltaLocked(PointerControllerInterface& pc,
                                     const FloatPoint& unconsumedDelta) REQUIRES(getLock());

    void populateFakeDisplayTopologyLocked(const std::vector<gui::DisplayInfo>& displayInfos)
            REQUIRES(getLock());

    std::optional<std::pair<const DisplayViewport*, float /*offset*/>> findDestinationDisplayLocked(
            const ui::LogicalDisplayId sourceDisplayId, const DisplayPosition sourceBoundary,
            float cursorOffset) const REQUIRES(getLock());

    static vec2 calculateDestinationPosition(const DisplayViewport& destinationViewport,
                                             float pointerOffset, DisplayPosition sourceBoundary);

    std::unordered_map<ui::LogicalDisplayId, std::vector<AdjacentDisplay>> mTopology
            GUARDED_BY(getLock());

    /* This listener keeps tracks of visible privacy sensitive displays and updates the
     * choreographer if there are any changes.
     *
     * Listener uses mListenerLock to guard all private data as choreographer and SurfaceComposer
     * both can call into the listener. To prevent deadlocks Choreographer can call listener with
     * its lock held, but listener must not call choreographer with its lock.
     */
    class PointerChoreographerDisplayInfoListener : public gui::WindowInfosListener {
    public:
        explicit PointerChoreographerDisplayInfoListener(PointerChoreographer* pc)
              : mPointerChoreographer(pc){};
        void onWindowInfosChanged(const gui::WindowInfosUpdate&) override;
        void setInitialDisplayInfosLocked(const std::vector<gui::WindowInfo>& windowInfos)
                REQUIRES(mLock);
        std::unordered_set<ui::LogicalDisplayId> getPrivacySensitiveDisplaysLocked()
                REQUIRES(mLock);
        void onPointerChoreographerDestroyed();

        // This lock is also used by PointerChoreographer. See PointerChoreographer::getLock().
        std::mutex mLock;

    private:
        PointerChoreographer* mPointerChoreographer GUARDED_BY(mLock);
        std::unordered_set<ui::LogicalDisplayId /*displayId*/> mPrivacySensitiveDisplays
                GUARDED_BY(mLock);
    };

    using ControllerConstructor =
            ConstructorDelegate<std::function<std::shared_ptr<PointerControllerInterface>()>>;
    ControllerConstructor mTouchControllerConstructor GUARDED_BY(getLock());
    ControllerConstructor getMouseControllerConstructor(ui::LogicalDisplayId displayId)
            REQUIRES(getLock());
    ControllerConstructor getStylusControllerConstructor(ui::LogicalDisplayId displayId)
            REQUIRES(getLock());

    InputListenerInterface& mNextListener;
    PointerChoreographerPolicyInterface& mPolicy;

    std::map<ui::LogicalDisplayId, std::shared_ptr<PointerControllerInterface>>
            mMousePointersByDisplay GUARDED_BY(getLock());
    std::map<DeviceId, std::shared_ptr<PointerControllerInterface>> mTouchPointersByDevice
            GUARDED_BY(getLock());
    std::map<DeviceId, std::shared_ptr<PointerControllerInterface>> mStylusPointersByDevice
            GUARDED_BY(getLock());
    std::map<DeviceId, std::shared_ptr<PointerControllerInterface>> mDrawingTabletPointersByDevice
            GUARDED_BY(getLock());

    ui::LogicalDisplayId mDefaultMouseDisplayId GUARDED_BY(getLock());
    ui::LogicalDisplayId mNotifiedPointerDisplayId GUARDED_BY(getLock());
    std::vector<InputDeviceInfo> mInputDeviceInfos GUARDED_BY(getLock());
    std::set<DeviceId> mMouseDevices GUARDED_BY(getLock());
    std::vector<DisplayViewport> mViewports GUARDED_BY(getLock());
    bool mShowTouchesEnabled GUARDED_BY(getLock());
    bool mStylusPointerIconEnabled GUARDED_BY(getLock());
    std::set<ui::LogicalDisplayId /*displayId*/> mDisplaysWithPointersHidden;
    ui::LogicalDisplayId mCurrentFocusedDisplay GUARDED_BY(getLock());

protected:
    using WindowListenerRegisterConsumer = std::function<std::vector<gui::WindowInfo>(
            const sp<android::gui::WindowInfosListener>&)>;
    using WindowListenerUnregisterConsumer =
            std::function<void(const sp<android::gui::WindowInfosListener>&)>;
    explicit PointerChoreographer(InputListenerInterface& listener,
                                  PointerChoreographerPolicyInterface&,
                                  const WindowListenerRegisterConsumer& registerListener,
                                  const WindowListenerUnregisterConsumer& unregisterListener);

private:
    // WindowInfoListener object should always exist while PointerChoreographer exists, because we
    // need to use the lock from it. But we don't always need to register the listener.
    bool mIsWindowInfoListenerRegistered GUARDED_BY(getLock());
    const sp<PointerChoreographerDisplayInfoListener> mWindowInfoListener;
    const WindowListenerRegisterConsumer mRegisterListener;
    const WindowListenerUnregisterConsumer mUnregisterListener;
};

} // namespace android