Define MotionEventFlag as an AIDL enum

This allows us to loop through all enum values defined in AIDL in native
code in a unit test to verify that they are all redefined in various
languages. This will help catch missed flag redefinitions in presubmit
rather than as runtime crashes.

Bug: 346613247
Test: libinput_rust_test
Flag: NONE no behavior change
Change-Id: I48c5119e28a91315c3bbc561616eb48750bfb804

5 files changed, 203 insertions, 135 deletions

diff --git a/include/input/Input.h b/include/input/Input.h
index ec08cdd163..456977bb34 100644
--- a/include/input/Input.h
+++ b/include/input/Input.h
@@ -25,6 +25,7 @@
 #include <android/input.h>
 #ifdef __linux__
 #include <android/os/IInputConstants.h>
+#include <android/os/MotionEventFlag.h>
 #endif
 #include <android/os/PointerIconType.h>
 #include <math.h>
@@ -69,15 +70,17 @@ enum {
      * actual intent.
      */
     AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED =
-            android::os::IInputConstants::MOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED,
+            static_cast<int32_t>(android::os::MotionEventFlag::WINDOW_IS_PARTIALLY_OBSCURED),
+
     AMOTION_EVENT_FLAG_HOVER_EXIT_PENDING =
-            android::os::IInputConstants::MOTION_EVENT_FLAG_HOVER_EXIT_PENDING,
+            static_cast<int32_t>(android::os::MotionEventFlag::HOVER_EXIT_PENDING),
+
     /**
      * This flag indicates that the event has been generated by a gesture generator. It
      * provides a hint to the GestureDetector to not apply any touch slop.
      */
     AMOTION_EVENT_FLAG_IS_GENERATED_GESTURE =
-            android::os::IInputConstants::MOTION_EVENT_FLAG_IS_GENERATED_GESTURE,
+            static_cast<int32_t>(android::os::MotionEventFlag::IS_GENERATED_GESTURE),
 
     /**
      * This flag indicates that the event will not cause a focus change if it is directed to an
@@ -86,27 +89,27 @@ enum {
      * into focus.
      */
     AMOTION_EVENT_FLAG_NO_FOCUS_CHANGE =
-            android::os::IInputConstants::MOTION_EVENT_FLAG_NO_FOCUS_CHANGE,
+            static_cast<int32_t>(android::os::MotionEventFlag::NO_FOCUS_CHANGE),
 
     /**
      * This event was generated or modified by accessibility service.
      */
     AMOTION_EVENT_FLAG_IS_ACCESSIBILITY_EVENT =
-            android::os::IInputConstants::INPUT_EVENT_FLAG_IS_ACCESSIBILITY_EVENT,
+            static_cast<int32_t>(android::os::MotionEventFlag::IS_ACCESSIBILITY_EVENT),
 
     AMOTION_EVENT_FLAG_TARGET_ACCESSIBILITY_FOCUS =
-            android::os::IInputConstants::MOTION_EVENT_FLAG_TARGET_ACCESSIBILITY_FOCUS,
+            static_cast<int32_t>(android::os::MotionEventFlag::TARGET_ACCESSIBILITY_FOCUS),
 
     /* Motion event is inconsistent with previously sent motion events. */
-    AMOTION_EVENT_FLAG_TAINTED = android::os::IInputConstants::INPUT_EVENT_FLAG_TAINTED,
+    AMOTION_EVENT_FLAG_TAINTED = static_cast<int32_t>(android::os::MotionEventFlag::TAINTED),
 
     /** Private flag, not used in Java. */
     AMOTION_EVENT_PRIVATE_FLAG_SUPPORTS_ORIENTATION =
-            android::os::IInputConstants::MOTION_EVENT_PRIVATE_FLAG_SUPPORTS_ORIENTATION,
+            static_cast<int32_t>(android::os::MotionEventFlag::PRIVATE_FLAG_SUPPORTS_ORIENTATION),
 
     /** Private flag, not used in Java. */
-    AMOTION_EVENT_PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION = android::os::IInputConstants::
-            MOTION_EVENT_PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION,
+    AMOTION_EVENT_PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION = static_cast<int32_t>(
+            android::os::MotionEventFlag::PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION),
 
     /** Mask for all private flags that are not used in Java. */
     AMOTION_EVENT_PRIVATE_FLAG_MASK = AMOTION_EVENT_PRIVATE_FLAG_SUPPORTS_ORIENTATION |
diff --git a/libs/input/Android.bp b/libs/input/Android.bp
index d782f42071..c2a7ebb614 100644
--- a/libs/input/Android.bp
+++ b/libs/input/Android.bp
@@ -30,6 +30,7 @@ filegroup {
         "android/os/InputEventInjectionResult.aidl",
         "android/os/InputEventInjectionSync.aidl",
         "android/os/InputConfig.aidl",
+        "android/os/MotionEventFlag.aidl",
         "android/os/PointerIconType.aidl",
     ],
 }
diff --git a/libs/input/android/os/IInputConstants.aidl b/libs/input/android/os/IInputConstants.aidl
index a77dfa59fe..e23fc94c5e 100644
--- a/libs/input/android/os/IInputConstants.aidl
+++ b/libs/input/android/os/IInputConstants.aidl
@@ -49,130 +49,24 @@ interface IInputConstants
     const int POLICY_FLAG_INJECTED_FROM_ACCESSIBILITY = 0x20000;
 
     /**
-     * This flag indicates that the window that received this motion event is partly
-     * or wholly obscured by another visible window above it and the event directly passed through
-     * the obscured area.
-     *
-     * A security sensitive application can check this flag to identify situations in which
-     * a malicious application may have covered up part of its content for the purpose
-     * of misleading the user or hijacking touches.  An appropriate response might be
-     * to drop the suspect touches or to take additional precautions to confirm the user's
-     * actual intent.
-     */
-    const int MOTION_EVENT_FLAG_WINDOW_IS_OBSCURED = 0x1;
-
-    /**
-     * This flag indicates that the window that received this motion event is partly
-     * or wholly obscured by another visible window above it and the event did not directly pass
-     * through the obscured area.
-     *
-     * A security sensitive application can check this flag to identify situations in which
-     * a malicious application may have covered up part of its content for the purpose
-     * of misleading the user or hijacking touches.  An appropriate response might be
-     * to drop the suspect touches or to take additional precautions to confirm the user's
-     * actual intent.
-     *
-     * Unlike FLAG_WINDOW_IS_OBSCURED, this is only true if the window that received this event is
-     * obstructed in areas other than the touched location.
-     */
-    const int MOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED = 0x2;
-
-    /**
-     * This private flag is only set on {@link #ACTION_HOVER_MOVE} events and indicates that
-     * this event will be immediately followed by a {@link #ACTION_HOVER_EXIT}. It is used to
-     * prevent generating redundant {@link #ACTION_HOVER_ENTER} events.
-     * @hide
-     */
-    const int MOTION_EVENT_FLAG_HOVER_EXIT_PENDING = 0x4;
-
-    /**
-     * This flag indicates that the event has been generated by a gesture generator. It
-     * provides a hint to the GestureDetector to not apply any touch slop.
-     *
-     * @hide
-     */
-    const int MOTION_EVENT_FLAG_IS_GENERATED_GESTURE = 0x8;
-
-    /**
-     * This flag is only set for events with {@link #ACTION_POINTER_UP} and {@link #ACTION_CANCEL}.
-     * It indicates that the pointer going up was an unintentional user touch. When FLAG_CANCELED
-     * is set, the typical actions that occur in response for a pointer going up (such as click
-     * handlers, end of drawing) should be aborted. This flag is typically set when the user was
-     * accidentally touching the screen, such as by gripping the device, or placing the palm on the
-     * screen.
-     *
-     * @see #ACTION_POINTER_UP
-     * @see #ACTION_CANCEL
+     * Common input event flag used for both motion and key events for a gesture or pointer being
+     * canceled.
      */
     const int INPUT_EVENT_FLAG_CANCELED = 0x20;
 
     /**
-     * This flag indicates that the event will not cause a focus change if it is directed to an
-     * unfocused window, even if it an {@link #ACTION_DOWN}. This is typically used with pointer
-     * gestures to allow the user to direct gestures to an unfocused window without bringing the
-     * window into focus.
-     * @hide
-     */
-    const int MOTION_EVENT_FLAG_NO_FOCUS_CHANGE = 0x40;
-
-    /**
-     * This flag indicates that the event has a valid value for AXIS_ORIENTATION.
-     *
-     * This is a private flag that is not used in Java.
-     * @hide
-     */
-    const int MOTION_EVENT_PRIVATE_FLAG_SUPPORTS_ORIENTATION = 0x80;
-
-    /**
-     * This flag indicates that the pointers' AXIS_ORIENTATION can be used to precisely determine
-     * the direction in which the tool is pointing. The value of the orientation axis will be in
-     * the range [-pi, pi], which represents a full circle. This is usually supported by devices
-     * like styluses.
-     *
-     * Conversely, AXIS_ORIENTATION cannot be used to tell which direction the tool is pointing
-     * when this flag is not set. In this case, the axis value will have a range of [-pi/2, pi/2],
-     * which represents half a circle. This is usually the case for devices like touchscreens and
-     * touchpads, for which it is difficult to tell which direction along the major axis of the
-     * touch ellipse the finger is pointing.
-     *
-     * This is a private flag that is not used in Java.
-     * @hide
-     */
-    const int MOTION_EVENT_PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION = 0x100;
-
-    /**
-     * The input event was generated or modified by accessibility service.
-     * Shared by both KeyEvent and MotionEvent flags, so this value should not overlap with either
-     * set of flags, including in input/Input.h and in android/input.h.
+     * Common input event flag used for both motion and key events, indicating that the event
+     * was generated or modified by accessibility service.
      */
     const int INPUT_EVENT_FLAG_IS_ACCESSIBILITY_EVENT = 0x800;
 
     /**
-     * Private flag that indicates when the system has detected that this motion event
-     * may be inconsistent with respect to the sequence of previously delivered motion events,
-     * such as when a pointer move event is sent but the pointer is not down.
-     *
-     * @hide
-     * @see #isTainted
-     * @see #setTainted
+     * Common input event flag used for both motion and key events, indicating that the system has
+     * detected this event may be inconsistent with the current event sequence or gesture, such as
+     * when a pointer move event is sent but the pointer is not down.
      */
     const int INPUT_EVENT_FLAG_TAINTED = 0x80000000;
 
-    /**
-     * Private flag indicating that this event was synthesized by the system and should be delivered
-     * to the accessibility focused view first. When being dispatched such an event is not handled
-     * by predecessors of the accessibility focused view and after the event reaches that view the
-     * flag is cleared and normal event dispatch is performed. This ensures that the platform can
-     * click on any view that has accessibility focus which is semantically equivalent to asking the
-     * view to perform a click accessibility action but more generic as views not implementing click
-     * action correctly can still be activated.
-     *
-     * @hide
-     * @see #isTargetAccessibilityFocus()
-     * @see #setTargetAccessibilityFocus(boolean)
-     */
-    const int MOTION_EVENT_FLAG_TARGET_ACCESSIBILITY_FOCUS = 0x40000000;
-
     /* The default pointer acceleration value. */
     const int DEFAULT_POINTER_ACCELERATION = 3;
 
diff --git a/libs/input/android/os/MotionEventFlag.aidl b/libs/input/android/os/MotionEventFlag.aidl
new file mode 100644
index 0000000000..2093b0636a
--- /dev/null
+++ b/libs/input/android/os/MotionEventFlag.aidl
@@ -0,0 +1,152 @@
+/**
+ * Copyright 2024, 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.
+ */
+
+package android.os;
+
+import android.os.IInputConstants;
+
+/**
+ * Flag definitions for MotionEvents.
+ * @hide
+ */
+@Backing(type="int")
+enum MotionEventFlag {
+
+    /**
+     * This flag indicates that the window that received this motion event is partly
+     * or wholly obscured by another visible window above it and the event directly passed through
+     * the obscured area.
+     *
+     * A security sensitive application can check this flag to identify situations in which
+     * a malicious application may have covered up part of its content for the purpose
+     * of misleading the user or hijacking touches.  An appropriate response might be
+     * to drop the suspect touches or to take additional precautions to confirm the user's
+     * actual intent.
+     */
+    WINDOW_IS_OBSCURED = 0x1,
+
+    /**
+     * This flag indicates that the window that received this motion event is partly
+     * or wholly obscured by another visible window above it and the event did not directly pass
+     * through the obscured area.
+     *
+     * A security sensitive application can check this flag to identify situations in which
+     * a malicious application may have covered up part of its content for the purpose
+     * of misleading the user or hijacking touches.  An appropriate response might be
+     * to drop the suspect touches or to take additional precautions to confirm the user's
+     * actual intent.
+     *
+     * Unlike FLAG_WINDOW_IS_OBSCURED, this is only true if the window that received this event is
+     * obstructed in areas other than the touched location.
+     */
+    WINDOW_IS_PARTIALLY_OBSCURED = 0x2,
+
+    /**
+     * This private flag is only set on {@link #ACTION_HOVER_MOVE} events and indicates that
+     * this event will be immediately followed by a {@link #ACTION_HOVER_EXIT}. It is used to
+     * prevent generating redundant {@link #ACTION_HOVER_ENTER} events.
+     * @hide
+     */
+    HOVER_EXIT_PENDING = 0x4,
+
+    /**
+     * This flag indicates that the event has been generated by a gesture generator. It
+     * provides a hint to the GestureDetector to not apply any touch slop.
+     *
+     * @hide
+     */
+    IS_GENERATED_GESTURE = 0x8,
+
+    /**
+     * This flag is only set for events with {@link #ACTION_POINTER_UP} and {@link #ACTION_CANCEL}.
+     * It indicates that the pointer going up was an unintentional user touch. When FLAG_CANCELED
+     * is set, the typical actions that occur in response for a pointer going up (such as click
+     * handlers, end of drawing) should be aborted. This flag is typically set when the user was
+     * accidentally touching the screen, such as by gripping the device, or placing the palm on the
+     * screen.
+     *
+     * @see #ACTION_POINTER_UP
+     * @see #ACTION_CANCEL
+     */
+    CANCELED = IInputConstants.INPUT_EVENT_FLAG_CANCELED,
+
+    /**
+     * This flag indicates that the event will not cause a focus change if it is directed to an
+     * unfocused window, even if it an {@link #ACTION_DOWN}. This is typically used with pointer
+     * gestures to allow the user to direct gestures to an unfocused window without bringing the
+     * window into focus.
+     * @hide
+     */
+    NO_FOCUS_CHANGE = 0x40,
+
+    /**
+     * This flag indicates that the event has a valid value for AXIS_ORIENTATION.
+     *
+     * This is a private flag that is not used in Java.
+     * @hide
+     */
+    PRIVATE_FLAG_SUPPORTS_ORIENTATION = 0x80,
+
+    /**
+     * This flag indicates that the pointers' AXIS_ORIENTATION can be used to precisely determine
+     * the direction in which the tool is pointing. The value of the orientation axis will be in
+     * the range [-pi, pi], which represents a full circle. This is usually supported by devices
+     * like styluses.
+     *
+     * Conversely, AXIS_ORIENTATION cannot be used to tell which direction the tool is pointing
+     * when this flag is not set. In this case, the axis value will have a range of [-pi/2, pi/2],
+     * which represents half a circle. This is usually the case for devices like touchscreens and
+     * touchpads, for which it is difficult to tell which direction along the major axis of the
+     * touch ellipse the finger is pointing.
+     *
+     * This is a private flag that is not used in Java.
+     * @hide
+     */
+    PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION = 0x100,
+
+    /**
+     * The input event was generated or modified by accessibility service.
+     * Shared by both KeyEvent and MotionEvent flags, so this value should not overlap with either
+     * set of flags, including in input/Input.h and in android/input.h.
+     */
+    IS_ACCESSIBILITY_EVENT = IInputConstants.INPUT_EVENT_FLAG_IS_ACCESSIBILITY_EVENT,
+
+    /**
+     * Private flag that indicates when the system has detected that this motion event
+     * may be inconsistent with respect to the sequence of previously delivered motion events,
+     * such as when a pointer move event is sent but the pointer is not down.
+     *
+     * @hide
+     * @see #isTainted
+     * @see #setTainted
+     */
+    TAINTED = IInputConstants.INPUT_EVENT_FLAG_TAINTED,
+
+    /**
+     * Private flag indicating that this event was synthesized by the system and should be delivered
+     * to the accessibility focused view first. When being dispatched such an event is not handled
+     * by predecessors of the accessibility focused view and after the event reaches that view the
+     * flag is cleared and normal event dispatch is performed. This ensures that the platform can
+     * click on any view that has accessibility focus which is semantically equivalent to asking the
+     * view to perform a click accessibility action but more generic as views not implementing click
+     * action correctly can still be activated.
+     *
+     * @hide
+     * @see #isTargetAccessibilityFocus()
+     * @see #setTargetAccessibilityFocus(boolean)
+     */
+    TARGET_ACCESSIBILITY_FOCUS = 0x40000000,
+}
diff --git a/libs/input/rust/input.rs b/libs/input/rust/input.rs
index 564d94dbb4..c46b7bb85c 100644
--- a/libs/input/rust/input.rs
+++ b/libs/input/rust/input.rs
@@ -19,6 +19,7 @@
 use crate::ffi::RustInputDeviceIdentifier;
 use bitflags::bitflags;
 use inputconstants::aidl::android::os::IInputConstants;
+use inputconstants::aidl::android::os::MotionEventFlag::MotionEventFlag;
 use std::fmt;
 
 /// The InputDevice ID.
@@ -193,31 +194,34 @@ impl MotionAction {
 
 bitflags! {
     /// MotionEvent flags.
+    /// The source of truth for the flag definitions are the MotionEventFlag AIDL enum.
+    /// The flag values are redefined here as a bitflags API.
     #[derive(Debug)]
     pub struct MotionFlags: u32 {
         /// FLAG_WINDOW_IS_OBSCURED
-        const WINDOW_IS_OBSCURED = IInputConstants::MOTION_EVENT_FLAG_WINDOW_IS_OBSCURED as u32;
+        const WINDOW_IS_OBSCURED = MotionEventFlag::WINDOW_IS_OBSCURED.0 as u32;
         /// FLAG_WINDOW_IS_PARTIALLY_OBSCURED
-        const WINDOW_IS_PARTIALLY_OBSCURED = IInputConstants::MOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED as u32;
+        const WINDOW_IS_PARTIALLY_OBSCURED = MotionEventFlag::WINDOW_IS_PARTIALLY_OBSCURED.0 as u32;
         /// FLAG_HOVER_EXIT_PENDING
-        const HOVER_EXIT_PENDING = IInputConstants::MOTION_EVENT_FLAG_HOVER_EXIT_PENDING as u32;
+        const HOVER_EXIT_PENDING = MotionEventFlag::HOVER_EXIT_PENDING.0 as u32;
         /// FLAG_IS_GENERATED_GESTURE
-        const IS_GENERATED_GESTURE = IInputConstants::MOTION_EVENT_FLAG_IS_GENERATED_GESTURE as u32;
+        const IS_GENERATED_GESTURE = MotionEventFlag::IS_GENERATED_GESTURE.0 as u32;
         /// FLAG_CANCELED
-        const CANCELED = IInputConstants::INPUT_EVENT_FLAG_CANCELED as u32;
+        const CANCELED = MotionEventFlag::CANCELED.0 as u32;
         /// FLAG_NO_FOCUS_CHANGE
-        const NO_FOCUS_CHANGE = IInputConstants::MOTION_EVENT_FLAG_NO_FOCUS_CHANGE as u32;
+        const NO_FOCUS_CHANGE = MotionEventFlag::NO_FOCUS_CHANGE.0 as u32;
         /// PRIVATE_FLAG_SUPPORTS_ORIENTATION
-        const PRIVATE_SUPPORTS_ORIENTATION = IInputConstants::MOTION_EVENT_PRIVATE_FLAG_SUPPORTS_ORIENTATION as u32;
+        const PRIVATE_FLAG_SUPPORTS_ORIENTATION =
+                MotionEventFlag::PRIVATE_FLAG_SUPPORTS_ORIENTATION.0 as u32;
         /// PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION
-        const PRIVATE_SUPPORTS_DIRECTIONAL_ORIENTATION =
-                IInputConstants::MOTION_EVENT_PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION as u32;
+        const PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION =
+                MotionEventFlag::PRIVATE_FLAG_SUPPORTS_DIRECTIONAL_ORIENTATION.0 as u32;
         /// FLAG_IS_ACCESSIBILITY_EVENT
-        const IS_ACCESSIBILITY_EVENT = IInputConstants::INPUT_EVENT_FLAG_IS_ACCESSIBILITY_EVENT as u32;
+        const IS_ACCESSIBILITY_EVENT = MotionEventFlag::IS_ACCESSIBILITY_EVENT.0 as u32;
         /// FLAG_TAINTED
-        const TAINTED = IInputConstants::INPUT_EVENT_FLAG_TAINTED as u32;
+        const TAINTED = MotionEventFlag::TAINTED.0 as u32;
         /// FLAG_TARGET_ACCESSIBILITY_FOCUS
-        const TARGET_ACCESSIBILITY_FOCUS = IInputConstants::MOTION_EVENT_FLAG_TARGET_ACCESSIBILITY_FOCUS as u32;
+        const TARGET_ACCESSIBILITY_FOCUS = MotionEventFlag::TARGET_ACCESSIBILITY_FOCUS.0 as u32;
     }
 }
 
@@ -333,10 +337,24 @@ pub enum KeyboardType {
 #[cfg(test)]
 mod tests {
     use crate::input::SourceClass;
+    use crate::MotionFlags;
     use crate::Source;
+    use inputconstants::aidl::android::os::MotionEventFlag::MotionEventFlag;
+
     #[test]
     fn convert_source_class_pointer() {
         let source = Source::from_bits(input_bindgen::AINPUT_SOURCE_CLASS_POINTER).unwrap();
         assert!(source.is_from_class(SourceClass::Pointer));
     }
+
+    /// Ensure all MotionEventFlag constants are re-defined in rust.
+    #[test]
+    fn all_motion_event_flags_defined() {
+        for flag in MotionEventFlag::enum_values() {
+            assert!(
+                MotionFlags::from_bits(flag.0 as u32).is_some(),
+                "MotionEventFlag value {flag:?} is not redefined as a rust MotionFlags"
+            );
+        }
+    }
 }