Virtual rotary encoder native support

 - detect rotary encoder input devices if they have a single scroll
   axis and nothing else

 - make the rotary mapper display-aware as the virtual rotary is
   constrained to a single virtual display, just like the other
   virtual input devices

Fix: 320328752
Test: atest inputflinger_tests
Test: see CTS in topic
Flag: android.companion.virtualdevice.flags.virtual_rotary

Change-Id: I5581013d06708cbcc2c3ac8a622cd259aea8a9b4
diff --git a/services/inputflinger/reader/Android.bp b/services/inputflinger/reader/Android.bp
index e76b648..b2f15b4 100644
--- a/services/inputflinger/reader/Android.bp
+++ b/services/inputflinger/reader/Android.bp
@@ -78,6 +78,7 @@
     name: "libinputreader_defaults",
     srcs: [":libinputreader_sources"],
     shared_libs: [
+        "android.companion.virtualdevice.flags-aconfig-cc-host",
         "libbase",
         "libcap",
         "libcrypto",
diff --git a/services/inputflinger/reader/EventHub.cpp b/services/inputflinger/reader/EventHub.cpp
index fe70a51..540f55d 100644
--- a/services/inputflinger/reader/EventHub.cpp
+++ b/services/inputflinger/reader/EventHub.cpp
@@ -33,6 +33,8 @@
 #include <sys/sysmacros.h>
 #include <unistd.h>
 
+#include <android_companion_virtualdevice_flags.h>
+
 #define LOG_TAG "EventHub"
 
 // #define LOG_NDEBUG 0
@@ -68,6 +70,8 @@
 
 namespace android {
 
+namespace vd_flags = android::companion::virtualdevice::flags;
+
 using namespace ftl::flag_operators;
 
 static const char* DEVICE_INPUT_PATH = "/dev/input";
@@ -2503,6 +2507,12 @@
         }
     }
 
+    // See if the device is a rotary encoder with a single scroll axis and nothing else.
+    if (vd_flags::virtual_rotary() && device->classes == ftl::Flags<InputDeviceClass>(0) &&
+        device->relBitmask.test(REL_WHEEL) && !device->relBitmask.test(REL_HWHEEL)) {
+        device->classes |= InputDeviceClass::ROTARY_ENCODER;
+    }
+
     // If the device isn't recognized as something we handle, don't monitor it.
     if (device->classes == ftl::Flags<InputDeviceClass>(0)) {
         ALOGV("Dropping device: id=%d, path='%s', name='%s'", deviceId, devicePath.c_str(),
diff --git a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp
index 27ff52f..20fd359 100644
--- a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp
@@ -84,12 +84,18 @@
         }
     }
     if (!changes.any() || changes.test(InputReaderConfiguration::Change::DISPLAY_INFO)) {
-        std::optional<DisplayViewport> internalViewport =
-                config.getDisplayViewportByType(ViewportType::INTERNAL);
-        if (internalViewport) {
-            mOrientation = internalViewport->orientation;
+        if (getDeviceContext().getAssociatedViewport()) {
+            mDisplayId = getDeviceContext().getAssociatedViewport()->displayId;
+            mOrientation = getDeviceContext().getAssociatedViewport()->orientation;
         } else {
-            mOrientation = ui::ROTATION_0;
+            mDisplayId = ui::LogicalDisplayId::INVALID;
+            std::optional<DisplayViewport> internalViewport =
+                    config.getDisplayViewportByType(ViewportType::INTERNAL);
+            if (internalViewport) {
+                mOrientation = internalViewport->orientation;
+            } else {
+                mOrientation = ui::ROTATION_0;
+            }
         }
     }
     return out;
@@ -124,8 +130,6 @@
     // Send motion event.
     if (scrolled) {
         int32_t metaState = getContext()->getGlobalMetaState();
-        // This is not a pointer, so it's not associated with a display.
-        ui::LogicalDisplayId displayId = ui::LogicalDisplayId::INVALID;
 
         if (mOrientation == ui::ROTATION_180) {
             scroll = -scroll;
@@ -147,7 +151,7 @@
 
         out.push_back(
                 NotifyMotionArgs(getContext()->getNextId(), when, readTime, getDeviceId(), mSource,
-                                 displayId, policyFlags, AMOTION_EVENT_ACTION_SCROLL, 0, 0,
+                                 mDisplayId, policyFlags, AMOTION_EVENT_ACTION_SCROLL, 0, 0,
                                  metaState, /*buttonState=*/0, MotionClassification::NONE,
                                  AMOTION_EVENT_EDGE_FLAG_NONE, 1, &pointerProperties,
                                  &pointerCoords, 0, 0, AMOTION_EVENT_INVALID_CURSOR_POSITION,
diff --git a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h
index 14c540b..7e80415 100644
--- a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h
+++ b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h
@@ -47,6 +47,7 @@
     int32_t mSource;
     float mScalingFactor;
     ui::Rotation mOrientation;
+    ui::LogicalDisplayId mDisplayId = ui::LogicalDisplayId::INVALID;
     std::unique_ptr<SlopController> mSlopController;
 
     explicit RotaryEncoderInputMapper(InputDeviceContext& deviceContext,