Call Filter from a separate function

The function 'processMotion' has gotten too long. To make it easier to
reason about, separate some code from the center of the function into a
new function.

Unfortunately, this new function will have side-effects, but it's still
easier to understand and reduces the number of local vars.

There's no functional change in this CL.

Bug: 241935838
Test: atest inputflinger_tests
Change-Id: I2157798b70299659791ae6ef85b2394e9130b4b3

2 files changed, 37 insertions, 20 deletions

diff --git a/services/inputflinger/UnwantedInteractionBlocker.cpp b/services/inputflinger/UnwantedInteractionBlocker.cpp
index 1c27a52d2e..fc8dfe678b 100644
--- a/services/inputflinger/UnwantedInteractionBlocker.cpp
+++ b/services/inputflinger/UnwantedInteractionBlocker.cpp
@@ -616,23 +616,7 @@ std::vector<::ui::InProgressTouchEvdev> getTouches(const NotifyMotionArgs& args,
     return touches;
 }
 
-std::vector<NotifyMotionArgs> PalmRejector::processMotion(const NotifyMotionArgs& args) {
-    if (mPalmDetectionFilter == nullptr) {
-        return {args};
-    }
-    const bool skipThisEvent = args.action == AMOTION_EVENT_ACTION_HOVER_ENTER ||
-            args.action == AMOTION_EVENT_ACTION_HOVER_MOVE ||
-            args.action == AMOTION_EVENT_ACTION_HOVER_EXIT ||
-            args.action == AMOTION_EVENT_ACTION_BUTTON_PRESS ||
-            args.action == AMOTION_EVENT_ACTION_BUTTON_RELEASE ||
-            args.action == AMOTION_EVENT_ACTION_SCROLL;
-    if (skipThisEvent) {
-        // Lets not process hover events, button events, or scroll for now.
-        return {args};
-    }
-    if (args.action == AMOTION_EVENT_ACTION_DOWN) {
-        mSuppressedPointerIds.clear();
-    }
+std::set<int32_t> PalmRejector::detectPalmPointers(const NotifyMotionArgs& args) {
     std::bitset<::ui::kNumTouchEvdevSlots> slotsToHold;
     std::bitset<::ui::kNumTouchEvdevSlots> slotsToSuppress;
 
@@ -640,6 +624,7 @@ std::vector<NotifyMotionArgs> PalmRejector::processMotion(const NotifyMotionArgs
     // the slots that have been removed due to the incoming event.
     SlotState oldSlotState = mSlotState;
     mSlotState.update(args);
+
     std::vector<::ui::InProgressTouchEvdev> touches =
             getTouches(args, mDeviceInfo, oldSlotState, mSlotState);
     ::base::TimeTicks chromeTimestamp = toChromeTimestamp(args.eventTime);
@@ -651,14 +636,14 @@ std::vector<NotifyMotionArgs> PalmRejector::processMotion(const NotifyMotionArgs
         }
         ALOGD("Filter: touches = %s", touchesStream.str().c_str());
     }
+
     mPalmDetectionFilter->Filter(touches, chromeTimestamp, &slotsToHold, &slotsToSuppress);
 
     ALOGD_IF(DEBUG_MODEL, "Response: slotsToHold = %s, slotsToSuppress = %s",
              slotsToHold.to_string().c_str(), slotsToSuppress.to_string().c_str());
 
     // Now that we know which slots should be suppressed, let's convert those to pointer id's.
-    std::set<int32_t> oldSuppressedIds;
-    std::swap(oldSuppressedIds, mSuppressedPointerIds);
+    std::set<int32_t> newSuppressedIds;
     for (size_t i = 0; i < args.pointerCount; i++) {
         const int32_t pointerId = args.pointerProperties[i].id;
         std::optional<size_t> slot = oldSlotState.getSlotForPointerId(pointerId);
@@ -667,9 +652,33 @@ std::vector<NotifyMotionArgs> PalmRejector::processMotion(const NotifyMotionArgs
             LOG_ALWAYS_FATAL_IF(!slot, "Could not find slot for pointer id %" PRId32, pointerId);
         }
         if (slotsToSuppress.test(*slot)) {
-            mSuppressedPointerIds.insert(pointerId);
+            newSuppressedIds.insert(pointerId);
         }
     }
+    return newSuppressedIds;
+}
+
+std::vector<NotifyMotionArgs> PalmRejector::processMotion(const NotifyMotionArgs& args) {
+    if (mPalmDetectionFilter == nullptr) {
+        return {args};
+    }
+    const bool skipThisEvent = args.action == AMOTION_EVENT_ACTION_HOVER_ENTER ||
+            args.action == AMOTION_EVENT_ACTION_HOVER_MOVE ||
+            args.action == AMOTION_EVENT_ACTION_HOVER_EXIT ||
+            args.action == AMOTION_EVENT_ACTION_BUTTON_PRESS ||
+            args.action == AMOTION_EVENT_ACTION_BUTTON_RELEASE ||
+            args.action == AMOTION_EVENT_ACTION_SCROLL;
+    if (skipThisEvent) {
+        // Lets not process hover events, button events, or scroll for now.
+        return {args};
+    }
+    if (args.action == AMOTION_EVENT_ACTION_DOWN) {
+        mSuppressedPointerIds.clear();
+    }
+
+    std::set<int32_t> oldSuppressedIds;
+    std::swap(oldSuppressedIds, mSuppressedPointerIds);
+    mSuppressedPointerIds = detectPalmPointers(args);
 
     std::vector<NotifyMotionArgs> argsWithoutUnwantedPointers =
             cancelSuppressedPointers(args, oldSuppressedIds, mSuppressedPointerIds);
diff --git a/services/inputflinger/UnwantedInteractionBlocker.h b/services/inputflinger/UnwantedInteractionBlocker.h
index 1878849452..a176a985c2 100644
--- a/services/inputflinger/UnwantedInteractionBlocker.h
+++ b/services/inputflinger/UnwantedInteractionBlocker.h
@@ -154,6 +154,14 @@ private:
     PalmRejector(const PalmRejector&) = delete;
     PalmRejector& operator=(const PalmRejector&) = delete;
 
+    /**
+     * Update the slot state and send this event to the palm rejection model for palm detection.
+     * Return the pointer ids that should be suppressed.
+     *
+     * This function is not const because it has side-effects. It will update the slot state using
+     * the incoming args! Also, it will call Filter(..), which has side-effects.
+     */
+    std::set<int32_t> detectPalmPointers(const NotifyMotionArgs& args);
     std::unique_ptr<::ui::SharedPalmDetectionFilterState> mSharedPalmState;
     AndroidPalmFilterDeviceInfo mDeviceInfo;
     std::unique_ptr<::ui::PalmDetectionFilter> mPalmDetectionFilter;