Support high-resolution scroll

VirtualMouse currently supports -1f to 1f float scroll values,
but it worked for integer values only as input framework supported
only REL_HWHEEL and REL_WHEEL events. With the introduction of
high-res scroll event support (REL_HWHEEL_HI_RES and REL_WHEEL_HI_RES),
granular mouse scrolling can be done, and VirtualMouse scroll API
would work for all float values.

Flag: android.companion.virtualdevice.flags.high_resolution_scroll
Test: atest VirtualMouseTest
Bug: 335160780
Change-Id: I7b13ac1722b6fd31736fe1c0117d4de6e838261a
diff --git a/services/inputflinger/reader/mapper/TouchInputMapper.h b/services/inputflinger/reader/mapper/TouchInputMapper.h
index beab6e7..87b72af 100644
--- a/services/inputflinger/reader/mapper/TouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/TouchInputMapper.h
@@ -339,8 +339,8 @@
         int32_t buttonState{};
 
         // Scroll state.
-        int32_t rawVScroll{};
-        int32_t rawHScroll{};
+        float rawVScroll{};
+        float rawHScroll{};
 
         inline void clear() { *this = RawState(); }
     };
diff --git a/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.cpp b/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.cpp
index f85cab2..06315e2 100644
--- a/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.cpp
+++ b/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.cpp
@@ -16,18 +16,29 @@
 
 #include "CursorScrollAccumulator.h"
 
+#include <android_companion_virtualdevice_flags.h>
 #include "EventHub.h"
 #include "InputDevice.h"
 
 namespace android {
 
-CursorScrollAccumulator::CursorScrollAccumulator() : mHaveRelWheel(false), mHaveRelHWheel(false) {
+namespace vd_flags = android::companion::virtualdevice::flags;
+
+CursorScrollAccumulator::CursorScrollAccumulator()
+      : mHaveRelWheel(false),
+        mHaveRelHWheel(false),
+        mHaveRelWheelHighRes(false),
+        mHaveRelHWheelHighRes(false) {
     clearRelativeAxes();
 }
 
 void CursorScrollAccumulator::configure(InputDeviceContext& deviceContext) {
     mHaveRelWheel = deviceContext.hasRelativeAxis(REL_WHEEL);
     mHaveRelHWheel = deviceContext.hasRelativeAxis(REL_HWHEEL);
+    if (vd_flags::high_resolution_scroll()) {
+        mHaveRelWheelHighRes = deviceContext.hasRelativeAxis(REL_WHEEL_HI_RES);
+        mHaveRelHWheelHighRes = deviceContext.hasRelativeAxis(REL_HWHEEL_HI_RES);
+    }
 }
 
 void CursorScrollAccumulator::reset(InputDeviceContext& deviceContext) {
@@ -42,11 +53,31 @@
 void CursorScrollAccumulator::process(const RawEvent& rawEvent) {
     if (rawEvent.type == EV_REL) {
         switch (rawEvent.code) {
+            case REL_WHEEL_HI_RES:
+                if (mHaveRelWheelHighRes) {
+                    mRelWheel = rawEvent.value /
+                            static_cast<float>(kEvdevMouseHighResScrollUnitsPerDetent);
+                }
+                break;
+            case REL_HWHEEL_HI_RES:
+                if (mHaveRelHWheelHighRes) {
+                    mRelHWheel = rawEvent.value /
+                            static_cast<float>(kEvdevMouseHighResScrollUnitsPerDetent);
+                }
+                break;
             case REL_WHEEL:
-                mRelWheel = rawEvent.value;
+                // We should ignore regular scroll events, if we have already have high-res scroll
+                // enabled.
+                if (!mHaveRelWheelHighRes) {
+                    mRelWheel = rawEvent.value;
+                }
                 break;
             case REL_HWHEEL:
-                mRelHWheel = rawEvent.value;
+                // We should ignore regular scroll events, if we have already have high-res scroll
+                // enabled.
+                if (!mHaveRelHWheelHighRes) {
+                    mRelHWheel = rawEvent.value;
+                }
                 break;
         }
     }
diff --git a/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.h b/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.h
index e563620..6990d20 100644
--- a/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.h
+++ b/services/inputflinger/reader/mapper/accumulator/CursorScrollAccumulator.h
@@ -24,7 +24,6 @@
 struct RawEvent;
 
 /* Keeps track of cursor scrolling motions. */
-
 class CursorScrollAccumulator {
 public:
     CursorScrollAccumulator();
@@ -39,17 +38,19 @@
 
     inline int32_t getRelativeX() const { return mRelX; }
     inline int32_t getRelativeY() const { return mRelY; }
-    inline int32_t getRelativeVWheel() const { return mRelWheel; }
-    inline int32_t getRelativeHWheel() const { return mRelHWheel; }
+    inline float getRelativeVWheel() const { return mRelWheel; }
+    inline float getRelativeHWheel() const { return mRelHWheel; }
 
 private:
     bool mHaveRelWheel;
     bool mHaveRelHWheel;
+    bool mHaveRelWheelHighRes;
+    bool mHaveRelHWheelHighRes;
 
     int32_t mRelX;
     int32_t mRelY;
-    int32_t mRelWheel;
-    int32_t mRelHWheel;
+    float mRelWheel;
+    float mRelHWheel;
 
     void clearRelativeAxes();
 };