Refactor input reader to add stylus support.

Bug: 5064702

Introduced the concept of an InputListener to further decouple
the InputReader from the InputDispatcher.  The InputListener
exposes just the minimum interface that the InputReader needs
to communicate with the outside world.  The InputReader
passes arguments to the InputListener by reference, which makes
it easy to queue them up.

Consolidated all of the InputReader locks into one simple global
Mutex.  The reason this wasn't done before was due to potential
re-entrance in outbound calls to the InputDispatcher.  To fix this,
the InputReader now queues up all of the events it wants to send
using a QueuedInputListener, then flushes them outside of the
critical section after all of the event processing is finished.
Removing all of the InputMapper locks greatly simplifies the
implementation.

Added tests for new stylus features such as buttons, tool types,
and hovering.

Added some helpers to BitSet32 to handle common code patterns
like finding the first marked bit and clearing it.

Fixed a bug in VelocityTracker where the wrong pointer trace
could get cleared when handling ACTION_POINTER_DOWN.  Oops.

Changed PointerCoords so it no longer stores useless zero
axis values.  Removed editAxisValue because it is not very
useful when all zero value axes are absent and therefore
cannot be edited in place.

Added dispatch of stylus hover events.

Added support for distance and tool types.

Change-Id: I4cf14d134fcb1db7d10be5f2af7b37deef8f8468

4 files changed, 49 insertions, 46 deletions

diff --git a/include/ui/Input.h b/include/ui/Input.h
index c9f694a8f0..f1385a0394 100644
--- a/include/ui/Input.h
+++ b/include/ui/Input.h
@@ -206,10 +206,17 @@ struct PointerCoords {
 
     float getAxisValue(int32_t axis) const;
     status_t setAxisValue(int32_t axis, float value);
-    float* editAxisValue(int32_t axis);
 
     void scale(float scale);
 
+    inline float getX() const {
+        return getAxisValue(AMOTION_EVENT_AXIS_X);
+    }
+
+    inline float getY() const {
+        return getAxisValue(AMOTION_EVENT_AXIS_Y);
+    }
+
 #ifdef HAVE_ANDROID_OS
     status_t readFromParcel(Parcel* parcel);
     status_t writeToParcel(Parcel* parcel) const;
diff --git a/include/utils/BitSet.h b/include/utils/BitSet.h
index 600017e89c..9452e86d61 100644
--- a/include/utils/BitSet.h
+++ b/include/utils/BitSet.h
@@ -68,6 +68,30 @@ struct BitSet32 {
     // Result is undefined if all bits are unmarked.
     inline uint32_t lastMarkedBit() const { return 31 - __builtin_ctz(value); }
 
+    // Finds the first marked bit in the set and clears it.  Returns the bit index.
+    // Result is undefined if all bits are unmarked.
+    inline uint32_t clearFirstMarkedBit() {
+        uint32_t n = firstMarkedBit();
+        clearBit(n);
+        return n;
+    }
+
+    // Finds the first unmarked bit in the set and marks it.  Returns the bit index.
+    // Result is undefined if all bits are marked.
+    inline uint32_t markFirstUnmarkedBit() {
+        uint32_t n = firstUnmarkedBit();
+        markBit(n);
+        return n;
+    }
+
+    // Finds the last marked bit in the set and clears it.  Returns the bit index.
+    // Result is undefined if all bits are unmarked.
+    inline uint32_t clearLastMarkedBit() {
+        uint32_t n = lastMarkedBit();
+        clearBit(n);
+        return n;
+    }
+
     // Gets the index of the specified bit in the set, which is the number of
     // marked bits that appear before the specified bit.
     inline uint32_t getIndexOfBit(uint32_t n) const {
diff --git a/libs/ui/Input.cpp b/libs/ui/Input.cpp
index 0af7f8043c..688b99892b 100644
--- a/libs/ui/Input.cpp
+++ b/libs/ui/Input.cpp
@@ -280,6 +280,9 @@ status_t PointerCoords::setAxisValue(int32_t axis, float value) {
     uint64_t axisBit = 1LL << axis;
     uint32_t index = __builtin_popcountll(bits & (axisBit - 1LL));
     if (!(bits & axisBit)) {
+        if (value == 0) {
+            return OK; // axes with value 0 do not need to be stored
+        }
         uint32_t count = __builtin_popcountll(bits);
         if (count >= MAX_AXES) {
             tooManyAxes(axis);
@@ -294,23 +297,10 @@ status_t PointerCoords::setAxisValue(int32_t axis, float value) {
     return OK;
 }
 
-float* PointerCoords::editAxisValue(int32_t axis) {
-    if (axis < 0 || axis > 63) {
-        return NULL;
-    }
-
-    uint64_t axisBit = 1LL << axis;
-    if (!(bits & axisBit)) {
-        return NULL;
-    }
-    uint32_t index = __builtin_popcountll(bits & (axisBit - 1LL));
-    return &values[index];
-}
-
 static inline void scaleAxisValue(PointerCoords& c, int axis, float scaleFactor) {
-    float* value = c.editAxisValue(axis);
-    if (value) {
-        *value *= scaleFactor;
+    float value = c.getAxisValue(axis);
+    if (value != 0) {
+        c.setAxisValue(axis, value * scaleFactor);
     }
 }
 
@@ -574,20 +564,14 @@ void MotionEvent::transform(const SkMatrix* matrix) {
     size_t numSamples = mSamplePointerCoords.size();
     for (size_t i = 0; i < numSamples; i++) {
         PointerCoords& c = mSamplePointerCoords.editItemAt(i);
-        float* xPtr = c.editAxisValue(AMOTION_EVENT_AXIS_X);
-        float* yPtr = c.editAxisValue(AMOTION_EVENT_AXIS_Y);
-        if (xPtr && yPtr) {
-            float x = *xPtr + oldXOffset;
-            float y = *yPtr + oldYOffset;
-            matrix->mapXY(SkFloatToScalar(x), SkFloatToScalar(y), & point);
-            *xPtr = SkScalarToFloat(point.fX) - newXOffset;
-            *yPtr = SkScalarToFloat(point.fY) - newYOffset;
-        }
+        float x = c.getAxisValue(AMOTION_EVENT_AXIS_X) + oldXOffset;
+        float y = c.getAxisValue(AMOTION_EVENT_AXIS_Y) + oldYOffset;
+        matrix->mapXY(SkFloatToScalar(x), SkFloatToScalar(y), &point);
+        c.setAxisValue(AMOTION_EVENT_AXIS_X, SkScalarToFloat(point.fX) - newXOffset);
+        c.setAxisValue(AMOTION_EVENT_AXIS_Y, SkScalarToFloat(point.fY) - newYOffset);
 
-        float* orientationPtr = c.editAxisValue(AMOTION_EVENT_AXIS_ORIENTATION);
-        if (orientationPtr) {
-            *orientationPtr = transformAngle(matrix, *orientationPtr);
-        }
+        float orientation = c.getAxisValue(AMOTION_EVENT_AXIS_ORIENTATION);
+        c.setAxisValue(AMOTION_EVENT_AXIS_ORIENTATION, transformAngle(matrix, orientation));
     }
 }
 
@@ -727,7 +711,7 @@ void VelocityTracker::addMovement(nsecs_t eventTime, BitSet32 idBits, const Posi
     }
 
     while (idBits.count() > MAX_POINTERS) {
-        idBits.clearBit(idBits.lastMarkedBit());
+        idBits.clearLastMarkedBit();
     }
 
     Movement& movement = mMovements[mIndex];
@@ -776,7 +760,7 @@ void VelocityTracker::addMovement(const MotionEvent* event) {
         // We do this on down instead of on up because the client may want to query the
         // final velocity for a pointer that just went up.
         BitSet32 downIdBits;
-        downIdBits.markBit(event->getActionIndex());
+        downIdBits.markBit(event->getPointerId(event->getActionIndex()));
         clearPointers(downIdBits);
         break;
     }
diff --git a/libs/ui/tests/InputEvent_test.cpp b/libs/ui/tests/InputEvent_test.cpp
index e48d5b7dc5..e21c464a19 100644
--- a/libs/ui/tests/InputEvent_test.cpp
+++ b/libs/ui/tests/InputEvent_test.cpp
@@ -52,9 +52,6 @@ TEST_F(PointerCoordsTest, AxisValues) {
     ASSERT_EQ(0, coords.getAxisValue(1))
             << "getAxisValue should return zero because axis is not present";
 
-    ASSERT_EQ(NULL, coords.editAxisValue(0))
-            << "editAxisValue should return null because axis is not present";
-
     // Set first axis.
     ASSERT_EQ(OK, coords.setAxisValue(1, 5));
     ASSERT_EQ(0x00000002ULL, coords.bits);
@@ -96,26 +93,17 @@ TEST_F(PointerCoordsTest, AxisValues) {
     ASSERT_EQ(2, coords.getAxisValue(3))
             << "getAxisValue should return value of axis";
 
-    // Edit an existing axis value in place.
-    valuePtr = coords.editAxisValue(1);
-    ASSERT_EQ(5, *valuePtr)
-            << "editAxisValue should return pointer to axis value";
-
-    *valuePtr = 7;
-    ASSERT_EQ(7, coords.getAxisValue(1))
-            << "getAxisValue should return value of axis";
-
     // Set an axis with an id between the others.  (inserting value in the middle)
     ASSERT_EQ(OK, coords.setAxisValue(2, 1));
     ASSERT_EQ(0x0000000fULL, coords.bits);
     ASSERT_EQ(4, coords.values[0]);
-    ASSERT_EQ(7, coords.values[1]);
+    ASSERT_EQ(5, coords.values[1]);
     ASSERT_EQ(1, coords.values[2]);
     ASSERT_EQ(2, coords.values[3]);
 
     ASSERT_EQ(4, coords.getAxisValue(0))
             << "getAxisValue should return value of axis";
-    ASSERT_EQ(7, coords.getAxisValue(1))
+    ASSERT_EQ(5, coords.getAxisValue(1))
             << "getAxisValue should return value of axis";
     ASSERT_EQ(1, coords.getAxisValue(2))
             << "getAxisValue should return value of axis";