Add event ID generator. (84b087ec) · Commits · e / os / android_frameworks_native-old

include/input/Input.h

+32 −0

Original line number	Diff line number	Diff line
		@@ -265,6 +265,38 @@ enum class MotionClassification : uint8_t {
		*/
		const char* motionClassificationToString(MotionClassification classification);

		/**
		* Generator of unique numbers used to identify input events.
		*
		* Layout of ID:
		* \|--------------------------\|---------------------------\|
		* \| 2 bits for source \| 30 bits for random number \|
		* \|--------------------------\|---------------------------\|
		*/
		class IdGenerator {
		private:
		static constexpr uint32_t SOURCE_SHIFT = 30;

		public:
		// Used to divide integer space to ensure no conflict among these sources./
		enum class Source : int32_t {
		INPUT_READER = 0x0 << SOURCE_SHIFT,
		INPUT_DISPATCHER = 0x1 << SOURCE_SHIFT,
		OTHER = 0x3 << SOURCE_SHIFT, // E.g. app injected events
		};
		IdGenerator(Source source);

		int32_t nextId() const;

		// Extract source from given id.
		static inline Source getSource(int32_t id) { return static_cast<Source>(SOURCE_MASK & id); }

		private:
		const Source mSource;

		static constexpr int32_t SOURCE_MASK = 0x3 << SOURCE_SHIFT;
		};

		/**
		* Invalid value for cursor position. Used for non-mouse events, tests and injected events. Don't
		* use it for direct comparison with any other value, because NaN isn't equal to itself according to

libs/input/Input.cpp

+29 −0

Original line number	Diff line number	Diff line
		@@ -17,7 +17,9 @@
		#define LOG_TAG "Input"
		//#define LOG_NDEBUG 0

		#include <cutils/compiler.h>
		#include <limits.h>
		#include <string.h>

		#include <input/Input.h>
		#include <input/InputDevice.h>
		@@ -25,6 +27,7 @@

		#ifdef __ANDROID__
		#include <binder/Parcel.h>
		#include <sys/random.h>
		#endif

		namespace android {
		@@ -40,6 +43,32 @@ const char* motionClassificationToString(MotionClassification classification) {
		}
		}

		// --- IdGenerator ---
		IdGenerator::IdGenerator(Source source) : mSource(source) {}

		int32_t IdGenerator::nextId() const {
		constexpr uint32_t SEQUENCE_NUMBER_MASK = ~SOURCE_MASK;
		int32_t id = 0;

		// Avoid building against syscall getrandom(2) on host, which will fail build on Mac. Host doesn't
		// use sequence number so just always return mSource.
		#ifdef __ANDROID__
		constexpr size_t BUF_LEN = sizeof(id);
		size_t totalBytes = 0;
		while (totalBytes < BUF_LEN) {
		ssize_t bytes = TEMP_FAILURE_RETRY(getrandom(&id, BUF_LEN, GRND_NONBLOCK));
		if (CC_UNLIKELY(bytes < 0)) {
		ALOGW("Failed to fill in random number for sequence number: %s.", strerror(errno));
		id = 0;
		break;
		}
		totalBytes += bytes;
		}
		#endif // __ANDROID__

		return (id & SEQUENCE_NUMBER_MASK) \| static_cast<int32_t>(mSource);
		}

		// --- InputEvent ---

		const char* inputEventTypeToString(int32_t type) {

libs/input/tests/Android.bp

+1 −0

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		@@ -2,6 +2,7 @@
		cc_test {
		name: "libinput_tests",
		srcs: [
		"IdGenerator_test.cpp",
		"InputChannel_test.cpp",
		"InputDevice_test.cpp",
		"InputEvent_test.cpp",

libs/input/tests/IdGenerator_test.cpp

0 → 100644

+52 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2020 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.
		*/

		#include <gtest/gtest.h>
		#include <input/Input.h>
		#include <ios>
		#include <memory>
		#include <unordered_set>

		namespace android::test {

		class IdGeneratorTest : public testing::TestWithParam<IdGenerator::Source> {
		protected:
		void SetUp() override { mGenerator.reset(new IdGenerator(GetParam())); }

		std::unique_ptr<IdGenerator> mGenerator;
		};

		TEST_P(IdGeneratorTest, GenerateRandomNumber) {
		for (int i = 0; i < 500; ++i) {
		mGenerator->nextId();
		}
		}

		TEST_P(IdGeneratorTest, GenerateRandomNumberWithProperFlag) {
		for (int i = 0; i < 500; ++i) {
		int32_t id = mGenerator->nextId();
		IdGenerator::Source source = IdGenerator::getSource(id);
		EXPECT_EQ(source, GetParam())
		<< std::hex << "Generator generated a value with wrong source. Value: 0x" << id
		<< " Source: 0x" << static_cast<int32_t>(source);
		}
		}

		INSTANTIATE_TEST_SUITE_P(SourceInstantiation, IdGeneratorTest,
		testing::Values(IdGenerator::Source::INPUT_READER,
		IdGenerator::Source::INPUT_DISPATCHER,
		IdGenerator::Source::OTHER));
		} // namespace android::test