Ensure channel receives a consistent touch stream

Add an event verifier to check the touch streams that are being sent to
the input channel.

If a stream is inconsistent, crash.

For now, only touch streams are being verified. Disable the feature
while the bugs are being fixed.

Bug: 267082966
Test: m inputflinger_tests && $ANDROID_HOST_OUT/nativetest64/inputflinger_tests/inputflinger_tests
Merged-In: Ibb8ab70b0019789c1a17dae0077be6b23d3d9139
Change-Id: Ibb8ab70b0019789c1a17dae0077be6b23d3d9139
(cherry picked from commit f06b672b3e433121037398c7255098ed0130c649)

2 files changed, 51 insertions, 0 deletions

diff --git a/include/input/InputTransport.h b/include/input/InputTransport.h
index 1c52792cf6..a1be542d7b 100644
--- a/include/input/InputTransport.h
+++ b/include/input/InputTransport.h
@@ -38,6 +38,7 @@
 #include <binder/IBinder.h>
 #include <binder/Parcelable.h>
 #include <input/Input.h>
+#include <input/InputVerifier.h>
 #include <sys/stat.h>
 #include <ui/Transform.h>
 #include <utils/BitSet.h>
@@ -444,6 +445,7 @@ public:
 
 private:
     std::shared_ptr<InputChannel> mChannel;
+    InputVerifier mInputVerifier;
 };
 
 /*
diff --git a/include/input/InputVerifier.h b/include/input/InputVerifier.h
new file mode 100644
index 0000000000..d4589f53b5
--- /dev/null
+++ b/include/input/InputVerifier.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2023 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.
+ */
+
+#pragma once
+
+#include <input/Input.h>
+#include <map>
+
+namespace android {
+
+/*
+ * Crash if the provided touch stream is inconsistent.
+ *
+ * TODO(b/211379801): Add support for hover events:
+ * - No hover move without enter
+ * - No touching pointers when hover enter
+ * - No hovering pointers when touching
+ * - Only 1 hovering pointer max
+ */
+class InputVerifier {
+public:
+    InputVerifier(const std::string& name);
+
+    void processMovement(int32_t deviceId, int32_t action, uint32_t pointerCount,
+                         const PointerProperties* pointerProperties,
+                         const PointerCoords* pointerCoords, int32_t flags);
+
+private:
+    const std::string mName;
+    std::map<int32_t /*deviceId*/, std::bitset<MAX_POINTER_ID + 1>> mTouchingPointerIdsByDevice;
+    void ensureTouchingPointersMatch(int32_t deviceId, uint32_t pointerCount,
+                                     const PointerProperties* pointerProperties,
+                                     const char* action) const;
+};
+
+} // namespace android