Implement KeyboardClassifier interface in rust

DD: go/project-imposter-android
This CL includes:
- Rust interface setup

Next CL to include:
- Basic categorization into alphabetic and non-alphabetic
- Updating categorization based on key presses

Test: atest --host libinput_rust_test
Test: atest inputflinger_tests
Bug: 263559234
Flag: com.android.input.flags.enable_keyboard_classifier_rust_impl
Change-Id: I52773be992ddd8efaa9546e0af8b0a78515d931c

1 files changed, 89 insertions, 0 deletions

diff --git a/libs/input/KeyboardClassifier.cpp b/libs/input/KeyboardClassifier.cpp
new file mode 100644
index 0000000000..0c2c7be582
--- /dev/null
+++ b/libs/input/KeyboardClassifier.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2024 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.
+ */
+
+#define LOG_TAG "KeyboardClassifier"
+
+#include <android-base/logging.h>
+#include <com_android_input_flags.h>
+#include <ftl/flags.h>
+#include <input/KeyboardClassifier.h>
+
+#include "input_cxx_bridge.rs.h"
+
+namespace input_flags = com::android::input::flags;
+
+using android::input::RustInputDeviceIdentifier;
+
+namespace android {
+
+KeyboardClassifier::KeyboardClassifier() {
+    if (input_flags::enable_keyboard_classifier()) {
+        mRustClassifier = android::input::keyboardClassifier::create();
+    }
+}
+
+KeyboardType KeyboardClassifier::getKeyboardType(DeviceId deviceId) {
+    if (mRustClassifier) {
+        return static_cast<KeyboardType>(
+                android::input::keyboardClassifier::getKeyboardType(**mRustClassifier, deviceId));
+    } else {
+        auto it = mKeyboardTypeMap.find(deviceId);
+        if (it == mKeyboardTypeMap.end()) {
+            return KeyboardType::NONE;
+        }
+        return it->second;
+    }
+}
+
+// Copied from EventHub.h
+const uint32_t DEVICE_CLASS_KEYBOARD = android::os::IInputConstants::DEVICE_CLASS_KEYBOARD;
+const uint32_t DEVICE_CLASS_ALPHAKEY = android::os::IInputConstants::DEVICE_CLASS_ALPHAKEY;
+
+void KeyboardClassifier::notifyKeyboardChanged(DeviceId deviceId,
+                                               const InputDeviceIdentifier& identifier,
+                                               uint32_t deviceClasses) {
+    if (mRustClassifier) {
+        RustInputDeviceIdentifier rustIdentifier;
+        rustIdentifier.name = identifier.name;
+        rustIdentifier.location = identifier.location;
+        rustIdentifier.unique_id = identifier.uniqueId;
+        rustIdentifier.bus = identifier.bus;
+        rustIdentifier.vendor = identifier.vendor;
+        rustIdentifier.product = identifier.product;
+        rustIdentifier.version = identifier.version;
+        rustIdentifier.descriptor = identifier.descriptor;
+        android::input::keyboardClassifier::notifyKeyboardChanged(**mRustClassifier, deviceId,
+                                                                  rustIdentifier, deviceClasses);
+    } else {
+        bool isKeyboard = (deviceClasses & DEVICE_CLASS_KEYBOARD) != 0;
+        bool hasAlphabeticKey = (deviceClasses & DEVICE_CLASS_ALPHAKEY) != 0;
+        mKeyboardTypeMap.insert_or_assign(deviceId,
+                                          isKeyboard ? (hasAlphabeticKey
+                                                                ? KeyboardType::ALPHABETIC
+                                                                : KeyboardType::NON_ALPHABETIC)
+                                                     : KeyboardType::NONE);
+    }
+}
+
+void KeyboardClassifier::processKey(DeviceId deviceId, int32_t evdevCode, uint32_t metaState) {
+    if (mRustClassifier &&
+        !android::input::keyboardClassifier::isFinalized(**mRustClassifier, deviceId)) {
+        android::input::keyboardClassifier::processKey(**mRustClassifier, deviceId, evdevCode,
+                                                       metaState);
+    }
+}
+
+} // namespace android