Add fixed read only flag to enable jerk prediction pruning

For now this flag will simply allow all motion predictions (no-op).

Test: atest libinput_tests
Bug: 266747654
Change-Id: If54b924223255c068fff26f8b6f21cdd31799aea

2 files changed, 21 insertions, 1 deletions

diff --git a/libs/input/MotionPredictor.cpp b/libs/input/MotionPredictor.cpp
index c4e3ff6dee..1df88dd497 100644
--- a/libs/input/MotionPredictor.cpp
+++ b/libs/input/MotionPredictor.cpp
@@ -22,17 +22,21 @@
 #include <cmath>
 #include <cstddef>
 #include <cstdint>
+#include <limits>
 #include <string>
 #include <vector>
 
 #include <android-base/logging.h>
 #include <android-base/strings.h>
 #include <android/input.h>
+#include <com_android_input_flags.h>
 
 #include <attestation/HmacKeyManager.h>
 #include <ftl/enum.h>
 #include <input/TfLiteMotionPredictor.h>
 
+namespace input_flags = com::android::input::flags;
+
 namespace android {
 namespace {
 
@@ -197,7 +201,14 @@ std::unique_ptr<MotionEvent> MotionPredictor::predict(nsecs_t timestamp) {
             // device starts to speed up, but avoids producing noisy predictions as it slows down.
             break;
         }
-        // TODO(b/266747654): Stop predictions if confidence is < some threshold.
+        if (input_flags::enable_prediction_pruning_via_jerk_thresholding()) {
+            // TODO(b/266747654): Stop predictions if confidence is < some threshold
+            // Arbitrarily high pruning index, will correct once jerk thresholding is implemented.
+            const size_t upperBoundPredictionIndex = std::numeric_limits<size_t>::max();
+            if (i > upperBoundPredictionIndex) {
+                break;
+            }
+        }
 
         const TfLiteMotionPredictorSample::Point predictedPoint =
                 convertPrediction(axisFrom, axisTo, predictedR[i], predictedPhi[i]);
diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
index b48b0fb924..e041c51cc9 100644
--- a/libs/input/input_flags.aconfig
+++ b/libs/input/input_flags.aconfig
@@ -128,3 +128,12 @@ flag {
   description: "Enable fling scrolling to be stopped by putting a finger on the touchpad again"
   bug: "281106755"
 }
+
+flag {
+  name: "enable_prediction_pruning_via_jerk_thresholding"
+  namespace: "input"
+  description: "Enable prediction pruning based on jerk thresholds."
+  bug: "266747654"
+  is_fixed_read_only: true
+
+}