Rotary encoder rotation count telemetry

Implements a telemetry using the Telemetry Express API to log full
rotations on rotary encoder devices. By default, logs are disabled for
rotations. A rotary input device can change the minimum logged rotation
value via the `rotary_encoder.min_rotations_to_log` IDC property, by
setting it to a positive integer value.

Bug: 370353565
Test: atest RotaryEncoderInputMapperTest
Test: manual with custom logs
Flag: com.android.input.flags.rotary_input_telemetry

Change-Id: I5162b0d343936ac8049c24835cd8e57d44643516

5 files changed, 237 insertions, 2 deletions

diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
index 60fb00e128..701fb43c1f 100644
--- a/libs/input/input_flags.aconfig
+++ b/libs/input/input_flags.aconfig
@@ -207,3 +207,10 @@ flag {
   description: "Allow user to enable key repeats or configure timeout before key repeat and key repeat delay rates."
   bug: "336585002"
 }
+
+flag {
+  name: "rotary_input_telemetry"
+  namespace: "wear_frameworks"
+  description: "Enable telemetry for rotary input"
+  bug: "370353565"
+}
diff --git a/services/inputflinger/reader/Android.bp b/services/inputflinger/reader/Android.bp
index b76e8c515f..b3cd35c936 100644
--- a/services/inputflinger/reader/Android.bp
+++ b/services/inputflinger/reader/Android.bp
@@ -90,10 +90,14 @@ cc_defaults {
         "libstatslog",
         "libstatspull",
         "libutils",
+        "libstatssocket",
     ],
     static_libs: [
         "libchrome-gestures",
         "libui-types",
+        "libexpresslog",
+        "libtextclassifier_hash_static",
+        "libstatslog_express",
     ],
     header_libs: [
         "libbatteryservice_headers",
diff --git a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp
index b72cc6e060..c633b495e4 100644
--- a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.cpp
@@ -20,6 +20,8 @@
 
 #include "RotaryEncoderInputMapper.h"
 
+#include <Counter.h>
+#include <com_android_input_flags.h>
 #include <utils/Timers.h>
 #include <optional>
 
@@ -27,14 +29,26 @@
 
 namespace android {
 
+using android::expresslog::Counter;
+
+constexpr float kDefaultResolution = 0;
 constexpr float kDefaultScaleFactor = 1.0f;
+constexpr int32_t kDefaultMinRotationsToLog = 3;
 
 RotaryEncoderInputMapper::RotaryEncoderInputMapper(InputDeviceContext& deviceContext,
                                                    const InputReaderConfiguration& readerConfig)
+      : RotaryEncoderInputMapper(deviceContext, readerConfig,
+                                 Counter::logIncrement /* telemetryLogCounter */) {}
+
+RotaryEncoderInputMapper::RotaryEncoderInputMapper(
+        InputDeviceContext& deviceContext, const InputReaderConfiguration& readerConfig,
+        std::function<void(const char*, int64_t)> telemetryLogCounter)
       : InputMapper(deviceContext, readerConfig),
         mSource(AINPUT_SOURCE_ROTARY_ENCODER),
         mScalingFactor(kDefaultScaleFactor),
-        mOrientation(ui::ROTATION_0) {}
+        mResolution(kDefaultResolution),
+        mOrientation(ui::ROTATION_0),
+        mTelemetryLogCounter(telemetryLogCounter) {}
 
 RotaryEncoderInputMapper::~RotaryEncoderInputMapper() {}
 
@@ -51,6 +65,7 @@ void RotaryEncoderInputMapper::populateDeviceInfo(InputDeviceInfo& info) {
         if (!res.has_value()) {
             ALOGW("Rotary Encoder device configuration file didn't specify resolution!\n");
         }
+        mResolution = res.value_or(kDefaultResolution);
         std::optional<float> scalingFactor = config.getFloat("device.scalingFactor");
         if (!scalingFactor.has_value()) {
             ALOGW("Rotary Encoder device configuration file didn't specify scaling factor,"
@@ -59,7 +74,22 @@ void RotaryEncoderInputMapper::populateDeviceInfo(InputDeviceInfo& info) {
         }
         mScalingFactor = scalingFactor.value_or(kDefaultScaleFactor);
         info.addMotionRange(AMOTION_EVENT_AXIS_SCROLL, mSource, -1.0f, 1.0f, 0.0f, 0.0f,
-                            res.value_or(0.0f) * mScalingFactor);
+                            mResolution * mScalingFactor);
+
+        if (com::android::input::flags::rotary_input_telemetry()) {
+            mMinRotationsToLog = config.getInt("rotary_encoder.min_rotations_to_log");
+            if (!mMinRotationsToLog.has_value()) {
+                ALOGI("Rotary Encoder device configuration file didn't specify min log rotation.");
+            } else if (*mMinRotationsToLog <= 0) {
+                ALOGE("Rotary Encoder device configuration specified non-positive min log rotation "
+                      ": %d. Telemetry logging of rotations disabled.",
+                      *mMinRotationsToLog);
+                mMinRotationsToLog = {};
+            } else {
+                ALOGD("Rotary Encoder telemetry enabled. mMinRotationsToLog=%d",
+                      *mMinRotationsToLog);
+            }
+        }
     }
 }
 
@@ -121,10 +151,29 @@ std::list<NotifyArgs> RotaryEncoderInputMapper::process(const RawEvent& rawEvent
     return out;
 }
 
+void RotaryEncoderInputMapper::logScroll(float scroll) {
+    if (mResolution <= 0 || !mMinRotationsToLog) return;
+
+    mUnloggedScrolls += fabs(scroll);
+
+    // unitsPerRotation = (2 * PI * radians) * (units per radian (i.e. resolution))
+    const float unitsPerRotation = 2 * M_PI * mResolution;
+    const float scrollsPerMinRotationsToLog = *mMinRotationsToLog * unitsPerRotation;
+    const int32_t numMinRotationsToLog =
+            static_cast<int32_t>(mUnloggedScrolls / scrollsPerMinRotationsToLog);
+    mUnloggedScrolls = std::fmod(mUnloggedScrolls, scrollsPerMinRotationsToLog);
+    if (numMinRotationsToLog) {
+        mTelemetryLogCounter("input.value_rotary_input_device_full_rotation_count",
+                             numMinRotationsToLog * (*mMinRotationsToLog));
+    }
+}
+
 std::list<NotifyArgs> RotaryEncoderInputMapper::sync(nsecs_t when, nsecs_t readTime) {
     std::list<NotifyArgs> out;
 
     float scroll = mRotaryEncoderScrollAccumulator.getRelativeVWheel();
+    logScroll(scroll);
+
     if (mSlopController) {
         scroll = mSlopController->consumeEvent(when, scroll);
     }
diff --git a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h
index 7e804150b1..d74ced180e 100644
--- a/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h
+++ b/services/inputflinger/reader/mapper/RotaryEncoderInputMapper.h
@@ -46,13 +46,39 @@ private:
 
     int32_t mSource;
     float mScalingFactor;
+    /** Units per rotation, provided via the `device.res` IDC property. */
+    float mResolution;
     ui::Rotation mOrientation;
+    /**
+     * The minimum number of rotations to log for telemetry.
+     * Provided via `rotary_encoder.min_rotations_to_log` IDC property. If no value is provided in
+     * the IDC file, or if a non-positive value is provided, the telemetry will be disabled, and
+     * this value is set to the empty optional.
+     */
+    std::optional<int32_t> mMinRotationsToLog;
+    /**
+     * A function to log count for telemetry.
+     * The char* is the logging key, and the int64_t is the value to log.
+     * Abstracting the actual logging APIs via this function is helpful for simple unit testing.
+     */
+    std::function<void(const char*, int64_t)> mTelemetryLogCounter;
     ui::LogicalDisplayId mDisplayId = ui::LogicalDisplayId::INVALID;
     std::unique_ptr<SlopController> mSlopController;
 
+    /** Amount of raw scrolls (pre-slop) not yet logged for telemetry. */
+    float mUnloggedScrolls = 0;
+
     explicit RotaryEncoderInputMapper(InputDeviceContext& deviceContext,
                                       const InputReaderConfiguration& readerConfig);
+
+    /** This is a test constructor that allows injecting the expresslog Counter logic. */
+    RotaryEncoderInputMapper(InputDeviceContext& deviceContext,
+                             const InputReaderConfiguration& readerConfig,
+                             std::function<void(const char*, int64_t)> expressLogCounter);
     [[nodiscard]] std::list<NotifyArgs> sync(nsecs_t when, nsecs_t readTime);
+
+    /** Logs a given amount of scroll for telemetry. */
+    void logScroll(float scroll);
 };
 
 } // namespace android
diff --git a/services/inputflinger/tests/RotaryEncoderInputMapper_test.cpp b/services/inputflinger/tests/RotaryEncoderInputMapper_test.cpp
index 6607bc7972..486d893944 100644
--- a/services/inputflinger/tests/RotaryEncoderInputMapper_test.cpp
+++ b/services/inputflinger/tests/RotaryEncoderInputMapper_test.cpp
@@ -23,6 +23,8 @@
 
 #include <android-base/logging.h>
 #include <android_companion_virtualdevice_flags.h>
+#include <com_android_input_flags.h>
+#include <flag_macros.h>
 #include <gtest/gtest.h>
 #include <input/DisplayViewport.h>
 #include <linux/input-event-codes.h>
@@ -100,6 +102,15 @@ protected:
         EXPECT_CALL(mMockEventHub, hasRelativeAxis(EVENTHUB_ID, REL_HWHEEL_HI_RES))
                 .WillRepeatedly(Return(false));
     }
+
+    std::map<const char*, int64_t> mTelemetryLogCounts;
+
+    /**
+     * A fake function for telemetry logging.
+     * Records the log counts in the `mTelemetryLogCounts` map.
+     */
+    std::function<void(const char*, int64_t)> mTelemetryLogCounter =
+            [this](const char* key, int64_t value) { mTelemetryLogCounts[key] += value; };
 };
 
 TEST_F(RotaryEncoderInputMapperTest, ConfigureDisplayIdWithAssociatedViewport) {
@@ -187,4 +198,142 @@ TEST_F(RotaryEncoderInputMapperTest, HighResScrollIgnoresRegularScroll) {
                               WithMotionAction(AMOTION_EVENT_ACTION_SCROLL), WithScroll(0.5f)))));
 }
 
+TEST_F_WITH_FLAGS(RotaryEncoderInputMapperTest, RotaryInputTelemetryFlagOff_NoRotationLogging,
+                  REQUIRES_FLAGS_DISABLED(ACONFIG_FLAG(com::android::input::flags,
+                                                       rotary_input_telemetry))) {
+    mPropertyMap.addProperty("device.res", "3");
+    mMapper = createInputMapper<RotaryEncoderInputMapper>(*mDeviceContext, mReaderConfiguration,
+                                                          mTelemetryLogCounter);
+    InputDeviceInfo info;
+    mMapper->populateDeviceInfo(info);
+
+    std::list<NotifyArgs> args;
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 70);
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+}
+
+TEST_F_WITH_FLAGS(RotaryEncoderInputMapperTest, ZeroResolution_NoRotationLogging,
+                  REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(com::android::input::flags,
+                                                      rotary_input_telemetry))) {
+    mPropertyMap.addProperty("device.res", "-3");
+    mPropertyMap.addProperty("rotary_encoder.min_rotations_to_log", "2");
+    mMapper = createInputMapper<RotaryEncoderInputMapper>(*mDeviceContext, mReaderConfiguration,
+                                                          mTelemetryLogCounter);
+    InputDeviceInfo info;
+    mMapper->populateDeviceInfo(info);
+
+    std::list<NotifyArgs> args;
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 700);
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+}
+
+TEST_F_WITH_FLAGS(RotaryEncoderInputMapperTest, NegativeMinLogRotation_NoRotationLogging,
+                  REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(com::android::input::flags,
+                                                      rotary_input_telemetry))) {
+    mPropertyMap.addProperty("device.res", "3");
+    mPropertyMap.addProperty("rotary_encoder.min_rotations_to_log", "-2");
+    mMapper = createInputMapper<RotaryEncoderInputMapper>(*mDeviceContext, mReaderConfiguration,
+                                                          mTelemetryLogCounter);
+    InputDeviceInfo info;
+    mMapper->populateDeviceInfo(info);
+
+    std::list<NotifyArgs> args;
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 700);
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+}
+
+TEST_F_WITH_FLAGS(RotaryEncoderInputMapperTest, ZeroMinLogRotation_NoRotationLogging,
+                  REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(com::android::input::flags,
+                                                      rotary_input_telemetry))) {
+    mPropertyMap.addProperty("device.res", "3");
+    mPropertyMap.addProperty("rotary_encoder.min_rotations_to_log", "0");
+    mMapper = createInputMapper<RotaryEncoderInputMapper>(*mDeviceContext, mReaderConfiguration,
+                                                          mTelemetryLogCounter);
+    InputDeviceInfo info;
+    mMapper->populateDeviceInfo(info);
+
+    std::list<NotifyArgs> args;
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 700);
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+}
+
+TEST_F_WITH_FLAGS(RotaryEncoderInputMapperTest, NoMinLogRotation_NoRotationLogging,
+                  REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(com::android::input::flags,
+                                                      rotary_input_telemetry))) {
+    // 3 units per radian, 2 * M_PI * 3 = ~18.85 units per rotation.
+    mPropertyMap.addProperty("device.res", "3");
+    mMapper = createInputMapper<RotaryEncoderInputMapper>(*mDeviceContext, mReaderConfiguration,
+                                                          mTelemetryLogCounter);
+    InputDeviceInfo info;
+    mMapper->populateDeviceInfo(info);
+
+    std::list<NotifyArgs> args;
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 700);
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+}
+
+TEST_F_WITH_FLAGS(RotaryEncoderInputMapperTest, RotationLogging,
+                  REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(com::android::input::flags,
+                                                      rotary_input_telemetry))) {
+    // 3 units per radian, 2 * M_PI * 3 = ~18.85 units per rotation.
+    // Multiples of `unitsPerRoation`, to easily follow the assertions below.
+    // [18.85, 37.7, 56.55, 75.4, 94.25, 113.1, 131.95, 150.8]
+    mPropertyMap.addProperty("device.res", "3");
+    mPropertyMap.addProperty("rotary_encoder.min_rotations_to_log", "2");
+
+    mMapper = createInputMapper<RotaryEncoderInputMapper>(*mDeviceContext, mReaderConfiguration,
+                                                          mTelemetryLogCounter);
+    InputDeviceInfo info;
+    mMapper->populateDeviceInfo(info);
+
+    std::list<NotifyArgs> args;
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 15); // total scroll = 15
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 13); // total scroll = 28
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+    // Expect 0 since `min_rotations_to_log` = 2, and total scroll 28 only has 1 rotation.
+    ASSERT_EQ(mTelemetryLogCounts.find("input.value_rotary_input_device_full_rotation_count"),
+              mTelemetryLogCounts.end());
+
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, 10); // total scroll = 38
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+    // Total scroll includes >= `min_rotations_to_log` (2), expect log.
+    ASSERT_EQ(mTelemetryLogCounts["input.value_rotary_input_device_full_rotation_count"], 2);
+
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, -22); // total scroll = 60
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+    // Expect no additional telemetry. Total rotation is 3, and total unlogged rotation is 1, which
+    // is less than `min_rotations_to_log`.
+    ASSERT_EQ(mTelemetryLogCounts["input.value_rotary_input_device_full_rotation_count"], 2);
+
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, -16); // total scroll = 76
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+    // Total unlogged rotation >= `min_rotations_to_log` (2), so expect 2 more logged rotation.
+    ASSERT_EQ(mTelemetryLogCounts["input.value_rotary_input_device_full_rotation_count"], 4);
+
+    args += process(ARBITRARY_TIME, EV_REL, REL_WHEEL, -76); // total scroll = 152
+    args += process(ARBITRARY_TIME, EV_SYN, SYN_REPORT, 0);
+    // Total unlogged scroll >= 4*`min_rotations_to_log`. Expect *all* unlogged rotations to be
+    // logged, even if that's more than multiple of `min_rotations_to_log`.
+    ASSERT_EQ(mTelemetryLogCounts["input.value_rotary_input_device_full_rotation_count"], 8);
+}
+
 } // namespace android
\ No newline at end of file