Merge "Add slow_keys input filter" into main

14 files changed, 1131 insertions, 29 deletions

diff --git a/services/inputflinger/InputFilter.cpp b/services/inputflinger/InputFilter.cpp
index 72c6f1a73b..1ada5e5678 100644
--- a/services/inputflinger/InputFilter.cpp
+++ b/services/inputflinger/InputFilter.cpp
@@ -118,6 +118,15 @@ void InputFilter::setAccessibilityBounceKeysThreshold(nsecs_t threshold) {
     }
 }
 
+void InputFilter::setAccessibilitySlowKeysThreshold(nsecs_t threshold) {
+    std::scoped_lock _l(mLock);
+
+    if (mConfig.slowKeysThresholdNs != threshold) {
+        mConfig.slowKeysThresholdNs = threshold;
+        notifyConfigurationChangedLocked();
+    }
+}
+
 void InputFilter::setAccessibilityStickyKeysEnabled(bool enabled) {
     std::scoped_lock _l(mLock);
 
diff --git a/services/inputflinger/InputFilter.h b/services/inputflinger/InputFilter.h
index 153d29dd53..4ddc9f4f6b 100644
--- a/services/inputflinger/InputFilter.h
+++ b/services/inputflinger/InputFilter.h
@@ -35,6 +35,7 @@ public:
      */
     virtual void dump(std::string& dump) = 0;
     virtual void setAccessibilityBounceKeysThreshold(nsecs_t threshold) = 0;
+    virtual void setAccessibilitySlowKeysThreshold(nsecs_t threshold) = 0;
     virtual void setAccessibilityStickyKeysEnabled(bool enabled) = 0;
 };
 
@@ -61,6 +62,7 @@ public:
     void notifyDeviceReset(const NotifyDeviceResetArgs& args) override;
     void notifyPointerCaptureChanged(const NotifyPointerCaptureChangedArgs& args) override;
     void setAccessibilityBounceKeysThreshold(nsecs_t threshold) override;
+    void setAccessibilitySlowKeysThreshold(nsecs_t threshold) override;
     void setAccessibilityStickyKeysEnabled(bool enabled) override;
     void dump(std::string& dump) override;
 
diff --git a/services/inputflinger/InputFilterCallbacks.cpp b/services/inputflinger/InputFilterCallbacks.cpp
index a8759b7cbd..6c3144230f 100644
--- a/services/inputflinger/InputFilterCallbacks.cpp
+++ b/services/inputflinger/InputFilterCallbacks.cpp
@@ -17,6 +17,11 @@
 #define LOG_TAG "InputFilterCallbacks"
 
 #include "InputFilterCallbacks.h"
+#include <aidl/com/android/server/inputflinger/BnInputThread.h>
+#include <android/binder_auto_utils.h>
+#include <utils/StrongPointer.h>
+#include <utils/Thread.h>
+#include <functional>
 
 namespace android {
 
@@ -29,6 +34,47 @@ NotifyKeyArgs keyEventToNotifyKeyArgs(const AidlKeyEvent& event) {
                          event.scanCode, event.metaState, event.downTime);
 }
 
+namespace {
+
+using namespace aidl::com::android::server::inputflinger;
+
+class InputFilterThreadImpl : public Thread {
+public:
+    explicit InputFilterThreadImpl(std::function<void()> loop)
+          : Thread(/*canCallJava=*/true), mThreadLoop(loop) {}
+
+    ~InputFilterThreadImpl() {}
+
+private:
+    std::function<void()> mThreadLoop;
+
+    bool threadLoop() override {
+        mThreadLoop();
+        return true;
+    }
+};
+
+class InputFilterThread : public BnInputThread {
+public:
+    InputFilterThread(std::shared_ptr<IInputThreadCallback> callback) : mCallback(callback) {
+        mThread = sp<InputFilterThreadImpl>::make([this]() { loopOnce(); });
+        mThread->run("InputFilterThread", ANDROID_PRIORITY_URGENT_DISPLAY);
+    }
+
+    ndk::ScopedAStatus finish() override {
+        mThread->requestExit();
+        return ndk::ScopedAStatus::ok();
+    }
+
+private:
+    sp<Thread> mThread;
+    std::shared_ptr<IInputThreadCallback> mCallback;
+
+    void loopOnce() { LOG_ALWAYS_FATAL_IF(!mCallback->loopOnce().isOk()); }
+};
+
+} // namespace
+
 InputFilterCallbacks::InputFilterCallbacks(InputListenerInterface& listener,
                                            InputFilterPolicyInterface& policy)
       : mNextListener(listener), mPolicy(policy) {}
@@ -49,6 +95,13 @@ ndk::ScopedAStatus InputFilterCallbacks::onModifierStateChanged(int32_t modifier
     return ndk::ScopedAStatus::ok();
 }
 
+ndk::ScopedAStatus InputFilterCallbacks::createInputFilterThread(
+        const std::shared_ptr<IInputThreadCallback>& callback,
+        std::shared_ptr<IInputThread>* aidl_return) {
+    *aidl_return = ndk::SharedRefBase::make<InputFilterThread>(callback);
+    return ndk::ScopedAStatus::ok();
+}
+
 uint32_t InputFilterCallbacks::getModifierState() {
     std::scoped_lock _l(mLock);
     return mStickyModifierState.modifierState;
diff --git a/services/inputflinger/InputFilterCallbacks.h b/services/inputflinger/InputFilterCallbacks.h
index 31c160aeb9..a74955b5c6 100644
--- a/services/inputflinger/InputFilterCallbacks.h
+++ b/services/inputflinger/InputFilterCallbacks.h
@@ -19,6 +19,7 @@
 #include <aidl/com/android/server/inputflinger/IInputFlingerRust.h>
 #include <android/binder_auto_utils.h>
 #include <utils/Mutex.h>
+#include <memory>
 #include <mutex>
 #include "InputFilterPolicyInterface.h"
 #include "InputListener.h"
@@ -31,6 +32,9 @@ namespace android {
 
 using IInputFilter = aidl::com::android::server::inputflinger::IInputFilter;
 using AidlKeyEvent = aidl::com::android::server::inputflinger::KeyEvent;
+using aidl::com::android::server::inputflinger::IInputThread;
+using IInputThreadCallback =
+        aidl::com::android::server::inputflinger::IInputThread::IInputThreadCallback;
 
 class InputFilterCallbacks : public IInputFilter::BnInputFilterCallbacks {
 public:
@@ -53,6 +57,9 @@ private:
     ndk::ScopedAStatus sendKeyEvent(const AidlKeyEvent& event) override;
     ndk::ScopedAStatus onModifierStateChanged(int32_t modifierState,
                                               int32_t lockedModifierState) override;
+    ndk::ScopedAStatus createInputFilterThread(
+            const std::shared_ptr<IInputThreadCallback>& callback,
+            std::shared_ptr<IInputThread>* aidl_return) override;
 };
 
 } // namespace android
\ No newline at end of file
diff --git a/services/inputflinger/aidl/com/android/server/inputflinger/IInputFilter.aidl b/services/inputflinger/aidl/com/android/server/inputflinger/IInputFilter.aidl
index 2921d30b22..994d1c4b1a 100644
--- a/services/inputflinger/aidl/com/android/server/inputflinger/IInputFilter.aidl
+++ b/services/inputflinger/aidl/com/android/server/inputflinger/IInputFilter.aidl
@@ -17,6 +17,8 @@
 package com.android.server.inputflinger;
 
 import com.android.server.inputflinger.DeviceInfo;
+import com.android.server.inputflinger.IInputThread;
+import com.android.server.inputflinger.IInputThread.IInputThreadCallback;
 import com.android.server.inputflinger.InputFilterConfiguration;
 import com.android.server.inputflinger.KeyEvent;
 
@@ -36,6 +38,9 @@ interface IInputFilter {
 
         /** Sends back modifier state */
         void onModifierStateChanged(int modifierState, int lockedModifierState);
+
+        /** Creates an Input filter thread */
+        IInputThread createInputFilterThread(in IInputThreadCallback callback);
     }
 
     /** Returns if InputFilter is enabled */
diff --git a/services/inputflinger/aidl/com/android/server/inputflinger/IInputThread.aidl b/services/inputflinger/aidl/com/android/server/inputflinger/IInputThread.aidl
new file mode 100644
index 0000000000..2f6b8fc6ff
--- /dev/null
+++ b/services/inputflinger/aidl/com/android/server/inputflinger/IInputThread.aidl
@@ -0,0 +1,45 @@
+/*
+ * 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.
+ */
+
+package com.android.server.inputflinger;
+
+/** Interface to handle and run things on an InputThread
+  * Exposes main functionality of InputThread.h to rust which internally used system/core/libutils
+  * infrastructure.
+  *
+  * <p>
+  * NOTE: Tried using rust provided threading infrastructure but that uses std::thread which doesn't
+  * have JNI support and can't call into Java policy that we use currently. libutils provided
+  * Thread.h also recommends against using std::thread and using the provided infrastructure that
+  * already provides way of attaching JniEnv to the created thread. So, we are using this interface
+  * to expose the InputThread infrastructure to rust.
+  * </p>
+  * TODO(b/321769871): Implement the threading infrastructure with JniEnv support in rust
+  */
+interface IInputThread {
+    /** Finish input thread (if not running, this call does nothing) */
+    void finish();
+
+    /** Callbacks from C++ to call into inputflinger rust components */
+    interface IInputThreadCallback {
+        /**
+          * The created thread will keep looping and calling this function.
+          * It's the responsibility of RUST component to appropriately put the thread to sleep and
+          * wake according to the use case.
+          */
+        void loopOnce();
+    }
+}
\ No newline at end of file
diff --git a/services/inputflinger/aidl/com/android/server/inputflinger/InputFilterConfiguration.aidl b/services/inputflinger/aidl/com/android/server/inputflinger/InputFilterConfiguration.aidl
index 38b161203b..9984a6a9ea 100644
--- a/services/inputflinger/aidl/com/android/server/inputflinger/InputFilterConfiguration.aidl
+++ b/services/inputflinger/aidl/com/android/server/inputflinger/InputFilterConfiguration.aidl
@@ -22,6 +22,8 @@ package com.android.server.inputflinger;
 parcelable InputFilterConfiguration {
     // Threshold value for Bounce keys filter (check bounce_keys_filter.rs)
     long bounceKeysThresholdNs;
-    // If sticky keys filter is enabled
+    // If sticky keys filter is enabled (check sticky_keys_filter.rs)
     boolean stickyKeysEnabled;
+    // Threshold value for Slow keys filter (check slow_keys_filter.rs)
+    long slowKeysThresholdNs;
 }
\ No newline at end of file
diff --git a/services/inputflinger/rust/Android.bp b/services/inputflinger/rust/Android.bp
index 2803805619..9e6dbe432d 100644
--- a/services/inputflinger/rust/Android.bp
+++ b/services/inputflinger/rust/Android.bp
@@ -42,6 +42,7 @@ rust_defaults {
         "libbinder_rs",
         "liblog_rust",
         "liblogger",
+        "libnix",
     ],
     host_supported: true,
 }
diff --git a/services/inputflinger/rust/bounce_keys_filter.rs b/services/inputflinger/rust/bounce_keys_filter.rs
index 894b881638..2d5039a1b1 100644
--- a/services/inputflinger/rust/bounce_keys_filter.rs
+++ b/services/inputflinger/rust/bounce_keys_filter.rs
@@ -118,6 +118,10 @@ impl Filter for BounceKeysFilter {
         }
         self.next.notify_devices_changed(device_infos);
     }
+
+    fn destroy(&mut self) {
+        self.next.destroy();
+    }
 }
 
 #[cfg(test)]
diff --git a/services/inputflinger/rust/input_filter.rs b/services/inputflinger/rust/input_filter.rs
index e94a71fbf8..a544fa36ae 100644
--- a/services/inputflinger/rust/input_filter.rs
+++ b/services/inputflinger/rust/input_filter.rs
@@ -22,11 +22,14 @@ use binder::{Interface, Strong};
 use com_android_server_inputflinger::aidl::com::android::server::inputflinger::{
     DeviceInfo::DeviceInfo,
     IInputFilter::{IInputFilter, IInputFilterCallbacks::IInputFilterCallbacks},
+    IInputThread::{IInputThread, IInputThreadCallback::IInputThreadCallback},
     InputFilterConfiguration::InputFilterConfiguration,
     KeyEvent::KeyEvent,
 };
 
 use crate::bounce_keys_filter::BounceKeysFilter;
+use crate::input_filter_thread::InputFilterThread;
+use crate::slow_keys_filter::SlowKeysFilter;
 use crate::sticky_keys_filter::StickyKeysFilter;
 use log::{error, info};
 use std::sync::{Arc, Mutex, RwLock};
@@ -35,6 +38,7 @@ use std::sync::{Arc, Mutex, RwLock};
 pub trait Filter {
     fn notify_key(&mut self, event: &KeyEvent);
     fn notify_devices_changed(&mut self, device_infos: &[DeviceInfo]);
+    fn destroy(&mut self);
 }
 
 struct InputFilterState {
@@ -50,6 +54,7 @@ pub struct InputFilter {
     // Access to mutable references to mutable state (includes access to filters, enabled, etc.) is
     // guarded by Mutex for thread safety
     state: Mutex<InputFilterState>,
+    input_filter_thread: InputFilterThread,
 }
 
 impl Interface for InputFilter {}
@@ -67,7 +72,11 @@ impl InputFilter {
         first_filter: Box<dyn Filter + Send + Sync>,
         callbacks: Arc<RwLock<Strong<dyn IInputFilterCallbacks>>>,
     ) -> InputFilter {
-        Self { callbacks, state: Mutex::new(InputFilterState { first_filter, enabled: false }) }
+        Self {
+            callbacks: callbacks.clone(),
+            state: Mutex::new(InputFilterState { first_filter, enabled: false }),
+            input_filter_thread: InputFilterThread::new(InputFilterThreadCreator::new(callbacks)),
+        }
     }
 }
 
@@ -89,24 +98,36 @@ impl IInputFilter for InputFilter {
     }
 
     fn notifyConfigurationChanged(&self, config: &InputFilterConfiguration) -> binder::Result<()> {
-        let mut state = self.state.lock().unwrap();
-        let mut first_filter: Box<dyn Filter + Send + Sync> =
-            Box::new(BaseFilter::new(self.callbacks.clone()));
-        if config.stickyKeysEnabled {
-            first_filter = Box::new(StickyKeysFilter::new(
-                first_filter,
-                ModifierStateListener::new(self.callbacks.clone()),
-            ));
-            state.enabled = true;
-            info!("Sticky keys filter is installed");
-        }
-        if config.bounceKeysThresholdNs > 0 {
-            first_filter =
-                Box::new(BounceKeysFilter::new(first_filter, config.bounceKeysThresholdNs));
-            state.enabled = true;
-            info!("Bounce keys filter is installed");
+        {
+            let mut state = self.state.lock().unwrap();
+            state.first_filter.destroy();
+            let mut first_filter: Box<dyn Filter + Send + Sync> =
+                Box::new(BaseFilter::new(self.callbacks.clone()));
+            if config.stickyKeysEnabled {
+                first_filter = Box::new(StickyKeysFilter::new(
+                    first_filter,
+                    ModifierStateListener::new(self.callbacks.clone()),
+                ));
+                state.enabled = true;
+                info!("Sticky keys filter is installed");
+            }
+            if config.slowKeysThresholdNs > 0 {
+                first_filter = Box::new(SlowKeysFilter::new(
+                    first_filter,
+                    config.slowKeysThresholdNs,
+                    self.input_filter_thread.clone(),
+                ));
+                state.enabled = true;
+                info!("Slow keys filter is installed");
+            }
+            if config.bounceKeysThresholdNs > 0 {
+                first_filter =
+                    Box::new(BounceKeysFilter::new(first_filter, config.bounceKeysThresholdNs));
+                state.enabled = true;
+                info!("Bounce keys filter is installed");
+            }
+            state.first_filter = first_filter;
         }
-        state.first_filter = first_filter;
         Result::Ok(())
     }
 }
@@ -132,27 +153,51 @@ impl Filter for BaseFilter {
     fn notify_devices_changed(&mut self, _device_infos: &[DeviceInfo]) {
         // do nothing
     }
-}
 
-pub struct ModifierStateListener {
-    callbacks: Arc<RwLock<Strong<dyn IInputFilterCallbacks>>>,
+    fn destroy(&mut self) {
+        // do nothing
+    }
 }
 
+/// This struct wraps around IInputFilterCallbacks restricting access to only
+/// {@code onModifierStateChanged()} method of the callback.
+#[derive(Clone)]
+pub struct ModifierStateListener(Arc<RwLock<Strong<dyn IInputFilterCallbacks>>>);
+
 impl ModifierStateListener {
-    /// Create a new InputFilter instance.
     pub fn new(callbacks: Arc<RwLock<Strong<dyn IInputFilterCallbacks>>>) -> ModifierStateListener {
-        Self { callbacks }
+        Self(callbacks)
     }
 
     pub fn modifier_state_changed(&self, modifier_state: u32, locked_modifier_state: u32) {
         let _ = self
-            .callbacks
+            .0
             .read()
             .unwrap()
             .onModifierStateChanged(modifier_state as i32, locked_modifier_state as i32);
     }
 }
 
+/// This struct wraps around IInputFilterCallbacks restricting access to only
+/// {@code createInputFilterThread()} method of the callback.
+#[derive(Clone)]
+pub struct InputFilterThreadCreator(Arc<RwLock<Strong<dyn IInputFilterCallbacks>>>);
+
+impl InputFilterThreadCreator {
+    pub fn new(
+        callbacks: Arc<RwLock<Strong<dyn IInputFilterCallbacks>>>,
+    ) -> InputFilterThreadCreator {
+        Self(callbacks)
+    }
+
+    pub fn create(
+        &self,
+        input_thread_callback: &Strong<dyn IInputThreadCallback>,
+    ) -> Strong<dyn IInputThread> {
+        self.0.read().unwrap().createInputFilterThread(input_thread_callback).unwrap()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::input_filter::{
@@ -218,7 +263,7 @@ mod tests {
         let input_filter = InputFilter::new(Strong::new(Box::new(test_callbacks)));
         let result = input_filter.notifyConfigurationChanged(&InputFilterConfiguration {
             bounceKeysThresholdNs: 100,
-            stickyKeysEnabled: false,
+            ..Default::default()
         });
         assert!(result.is_ok());
         let result = input_filter.isEnabled();
@@ -231,8 +276,8 @@ mod tests {
         let test_callbacks = TestCallbacks::new();
         let input_filter = InputFilter::new(Strong::new(Box::new(test_callbacks)));
         let result = input_filter.notifyConfigurationChanged(&InputFilterConfiguration {
-            bounceKeysThresholdNs: 0,
             stickyKeysEnabled: true,
+            ..Default::default()
         });
         assert!(result.is_ok());
         let result = input_filter.isEnabled();
@@ -240,6 +285,33 @@ mod tests {
         assert!(result.unwrap());
     }
 
+    #[test]
+    fn test_notify_configuration_changed_enabled_slow_keys() {
+        let test_callbacks = TestCallbacks::new();
+        let input_filter = InputFilter::new(Strong::new(Box::new(test_callbacks)));
+        let result = input_filter.notifyConfigurationChanged(&InputFilterConfiguration {
+            slowKeysThresholdNs: 100,
+            ..Default::default()
+        });
+        assert!(result.is_ok());
+        let result = input_filter.isEnabled();
+        assert!(result.is_ok());
+        assert!(result.unwrap());
+    }
+
+    #[test]
+    fn test_notify_configuration_changed_destroys_existing_filters() {
+        let test_filter = TestFilter::new();
+        let test_callbacks = TestCallbacks::new();
+        let input_filter = InputFilter::create_input_filter(
+            Box::new(test_filter.clone()),
+            Arc::new(RwLock::new(Strong::new(Box::new(test_callbacks)))),
+        );
+        let _ = input_filter
+            .notifyConfigurationChanged(&InputFilterConfiguration { ..Default::default() });
+        assert!(test_filter.is_destroy_called());
+    }
+
     fn create_key_event() -> KeyEvent {
         KeyEvent {
             id: 1,
@@ -271,6 +343,7 @@ pub mod test_filter {
     struct TestFilterInner {
         is_device_changed_called: bool,
         last_event: Option<KeyEvent>,
+        is_destroy_called: bool,
     }
 
     #[derive(Default, Clone)]
@@ -296,6 +369,10 @@ pub mod test_filter {
         pub fn is_device_changed_called(&self) -> bool {
             self.0.read().unwrap().is_device_changed_called
         }
+
+        pub fn is_destroy_called(&self) -> bool {
+            self.0.read().unwrap().is_destroy_called
+        }
     }
 
     impl Filter for TestFilter {
@@ -305,14 +382,19 @@ pub mod test_filter {
         fn notify_devices_changed(&mut self, _device_infos: &[DeviceInfo]) {
             self.inner().is_device_changed_called = true;
         }
+        fn destroy(&mut self) {
+            self.inner().is_destroy_called = true;
+        }
     }
 }
 
 #[cfg(test)]
 pub mod test_callbacks {
-    use binder::Interface;
+    use binder::{BinderFeatures, Interface, Strong};
     use com_android_server_inputflinger::aidl::com::android::server::inputflinger::{
-        IInputFilter::IInputFilterCallbacks::IInputFilterCallbacks, KeyEvent::KeyEvent,
+        IInputFilter::IInputFilterCallbacks::IInputFilterCallbacks,
+        IInputThread::{BnInputThread, IInputThread, IInputThreadCallback::IInputThreadCallback},
+        KeyEvent::KeyEvent,
     };
     use std::sync::{Arc, RwLock, RwLockWriteGuard};
 
@@ -321,6 +403,7 @@ pub mod test_callbacks {
         last_modifier_state: u32,
         last_locked_modifier_state: u32,
         last_event: Option<KeyEvent>,
+        test_thread: Option<TestThread>,
     }
 
     #[derive(Default, Clone)]
@@ -354,6 +437,17 @@ pub mod test_callbacks {
         pub fn get_last_locked_modifier_state(&self) -> u32 {
             self.0.read().unwrap().last_locked_modifier_state
         }
+
+        pub fn is_thread_created(&self) -> bool {
+            self.0.read().unwrap().test_thread.is_some()
+        }
+
+        pub fn is_thread_finished(&self) -> bool {
+            if let Some(test_thread) = &self.0.read().unwrap().test_thread {
+                return test_thread.is_finish_called();
+            }
+            false
+        }
     }
 
     impl IInputFilterCallbacks for TestCallbacks {
@@ -371,5 +465,45 @@ pub mod test_callbacks {
             self.inner().last_locked_modifier_state = locked_modifier_state as u32;
             Result::Ok(())
         }
+
+        fn createInputFilterThread(
+            &self,
+            _callback: &Strong<dyn IInputThreadCallback>,
+        ) -> std::result::Result<Strong<dyn IInputThread>, binder::Status> {
+            let test_thread = TestThread::new();
+            self.inner().test_thread = Some(test_thread.clone());
+            Result::Ok(BnInputThread::new_binder(test_thread, BinderFeatures::default()))
+        }
+    }
+
+    #[derive(Default)]
+    struct TestThreadInner {
+        is_finish_called: bool,
+    }
+
+    #[derive(Default, Clone)]
+    struct TestThread(Arc<RwLock<TestThreadInner>>);
+
+    impl Interface for TestThread {}
+
+    impl TestThread {
+        pub fn new() -> Self {
+            Default::default()
+        }
+
+        fn inner(&self) -> RwLockWriteGuard<'_, TestThreadInner> {
+            self.0.write().unwrap()
+        }
+
+        pub fn is_finish_called(&self) -> bool {
+            self.0.read().unwrap().is_finish_called
+        }
+    }
+
+    impl IInputThread for TestThread {
+        fn finish(&self) -> binder::Result<()> {
+            self.inner().is_finish_called = true;
+            Result::Ok(())
+        }
     }
 }
diff --git a/services/inputflinger/rust/input_filter_thread.rs b/services/inputflinger/rust/input_filter_thread.rs
new file mode 100644
index 0000000000..2d503aee70
--- /dev/null
+++ b/services/inputflinger/rust/input_filter_thread.rs
@@ -0,0 +1,452 @@
+/*
+ * 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.
+ */
+
+//! Input filter thread implementation in rust.
+//! Using IInputFilter.aidl interface to create ever looping thread with JNI support, rest of
+//! thread handling is done from rust side.
+//!
+//! NOTE: Tried using rust provided threading infrastructure but that uses std::thread which doesn't
+//! have JNI support and can't call into Java policy that we use currently. libutils provided
+//! Thread.h also recommends against using std::thread and using the provided infrastructure that
+//! already provides way of attaching JniEnv to the created thread. So, we are using an AIDL
+//! interface to expose the InputThread infrastructure to rust.
+
+use crate::input_filter::InputFilterThreadCreator;
+use binder::{BinderFeatures, Interface, Strong};
+use com_android_server_inputflinger::aidl::com::android::server::inputflinger::IInputThread::{
+    IInputThread, IInputThreadCallback::BnInputThreadCallback,
+    IInputThreadCallback::IInputThreadCallback,
+};
+use log::{debug, error};
+use nix::{sys::time::TimeValLike, time::clock_gettime, time::ClockId};
+use std::sync::{Arc, RwLock, RwLockWriteGuard};
+use std::time::Duration;
+use std::{thread, thread::Thread};
+
+/// Interface to receive callback from Input filter thread
+pub trait ThreadCallback {
+    /// Calls back after the requested timeout expires.
+    /// {@see InputFilterThread.request_timeout_at_time(...)}
+    ///
+    /// NOTE: In case of multiple requests, the timeout request which is earliest in time, will be
+    /// fulfilled and notified to all the listeners. It's up to the listeners to re-request another
+    /// timeout in the future.
+    fn notify_timeout_expired(&self, when_nanos: i64);
+    /// Unique name for the listener, which will be used to uniquely identify the listener.
+    fn name(&self) -> &str;
+}
+
+#[derive(Clone)]
+pub struct InputFilterThread {
+    thread_creator: InputFilterThreadCreator,
+    thread_callback_handler: ThreadCallbackHandler,
+    inner: Arc<RwLock<InputFilterThreadInner>>,
+}
+
+struct InputFilterThreadInner {
+    cpp_thread: Option<Strong<dyn IInputThread>>,
+    looper: Option<Thread>,
+    next_timeout: i64,
+    is_finishing: bool,
+}
+
+impl InputFilterThread {
+    /// Create a new InputFilterThread instance.
+    /// NOTE: This will create a new thread. Clone the existing instance to reuse the same thread.
+    pub fn new(thread_creator: InputFilterThreadCreator) -> InputFilterThread {
+        Self {
+            thread_creator,
+            thread_callback_handler: ThreadCallbackHandler::new(),
+            inner: Arc::new(RwLock::new(InputFilterThreadInner {
+                cpp_thread: None,
+                looper: None,
+                next_timeout: i64::MAX,
+                is_finishing: false,
+            })),
+        }
+    }
+
+    /// Listener requesting a timeout in future will receive a callback at or before the requested
+    /// time on the input filter thread.
+    /// {@see ThreadCallback.notify_timeout_expired(...)}
+    pub fn request_timeout_at_time(&self, when_nanos: i64) {
+        let filter_thread = &mut self.filter_thread();
+        if when_nanos < filter_thread.next_timeout {
+            filter_thread.next_timeout = when_nanos;
+            if let Some(looper) = &filter_thread.looper {
+                looper.unpark();
+            }
+        }
+    }
+
+    /// Registers a callback listener.
+    ///
+    /// NOTE: If a listener with the same name already exists when registering using
+    /// {@see InputFilterThread.register_thread_callback(...)}, we will ignore the listener. You
+    /// must clear any previously registered listeners using
+    /// {@see InputFilterThread.unregister_thread_callback(...) before registering the new listener.
+    ///
+    /// NOTE: Also, registering a callback will start the looper if not already started.
+    pub fn register_thread_callback(&self, callback: Box<dyn ThreadCallback + Send + Sync>) {
+        self.thread_callback_handler.register_thread_callback(callback);
+        self.start();
+    }
+
+    /// Unregisters a callback listener.
+    ///
+    /// NOTE: Unregistering a callback will stop the looper if not other callback registered.
+    pub fn unregister_thread_callback(&self, callback: Box<dyn ThreadCallback + Send + Sync>) {
+        self.thread_callback_handler.unregister_thread_callback(callback);
+        // Stop the thread if no registered callbacks exist. We will recreate the thread when new
+        // callbacks are registered.
+        let has_callbacks = self.thread_callback_handler.has_callbacks();
+        if !has_callbacks {
+            self.stop();
+        }
+    }
+
+    fn start(&self) {
+        debug!("InputFilterThread: start thread");
+        let filter_thread = &mut self.filter_thread();
+        if filter_thread.cpp_thread.is_none() {
+            filter_thread.cpp_thread = Some(self.thread_creator.create(
+                &BnInputThreadCallback::new_binder(self.clone(), BinderFeatures::default()),
+            ));
+            filter_thread.looper = None;
+            filter_thread.is_finishing = false;
+        }
+    }
+
+    fn stop(&self) {
+        debug!("InputFilterThread: stop thread");
+        let filter_thread = &mut self.filter_thread();
+        filter_thread.is_finishing = true;
+        if let Some(looper) = &filter_thread.looper {
+            looper.unpark();
+        }
+        if let Some(cpp_thread) = &filter_thread.cpp_thread {
+            let _ = cpp_thread.finish();
+        }
+        // Clear all references
+        filter_thread.cpp_thread = None;
+        filter_thread.looper = None;
+    }
+
+    fn loop_once(&self, now: i64) {
+        let mut wake_up_time = i64::MAX;
+        let mut timeout_expired = false;
+        {
+            // acquire thread lock
+            let filter_thread = &mut self.filter_thread();
+            if filter_thread.is_finishing {
+                // Thread is finishing so don't block processing on it and let it loop.
+                return;
+            }
+            if filter_thread.next_timeout != i64::MAX {
+                if filter_thread.next_timeout <= now {
+                    timeout_expired = true;
+                    filter_thread.next_timeout = i64::MAX;
+                } else {
+                    wake_up_time = filter_thread.next_timeout;
+                }
+            }
+            if filter_thread.looper.is_none() {
+                filter_thread.looper = Some(std::thread::current());
+            }
+        } // release thread lock
+        if timeout_expired {
+            self.thread_callback_handler.notify_timeout_expired(now);
+        }
+        if wake_up_time == i64::MAX {
+            thread::park();
+        } else {
+            let duration_now = Duration::from_nanos(now as u64);
+            let duration_wake_up = Duration::from_nanos(wake_up_time as u64);
+            thread::park_timeout(duration_wake_up - duration_now);
+        }
+    }
+
+    fn filter_thread(&self) -> RwLockWriteGuard<'_, InputFilterThreadInner> {
+        self.inner.write().unwrap()
+    }
+}
+
+impl Interface for InputFilterThread {}
+
+impl IInputThreadCallback for InputFilterThread {
+    fn loopOnce(&self) -> binder::Result<()> {
+        self.loop_once(clock_gettime(ClockId::CLOCK_MONOTONIC).unwrap().num_nanoseconds());
+        Result::Ok(())
+    }
+}
+
+#[derive(Default, Clone)]
+struct ThreadCallbackHandler(Arc<RwLock<ThreadCallbackHandlerInner>>);
+
+#[derive(Default)]
+struct ThreadCallbackHandlerInner {
+    callbacks: Vec<Box<dyn ThreadCallback + Send + Sync>>,
+}
+
+impl ThreadCallbackHandler {
+    fn new() -> Self {
+        Default::default()
+    }
+
+    fn has_callbacks(&self) -> bool {
+        !&self.0.read().unwrap().callbacks.is_empty()
+    }
+
+    fn register_thread_callback(&self, callback: Box<dyn ThreadCallback + Send + Sync>) {
+        let callbacks = &mut self.0.write().unwrap().callbacks;
+        if callbacks.iter().any(|x| x.name() == callback.name()) {
+            error!(
+                "InputFilterThread: register_thread_callback, callback {:?} already exists!",
+                callback.name()
+            );
+            return;
+        }
+        debug!(
+            "InputFilterThread: register_thread_callback, callback {:?} added!",
+            callback.name()
+        );
+        callbacks.push(callback);
+    }
+
+    fn unregister_thread_callback(&self, callback: Box<dyn ThreadCallback + Send + Sync>) {
+        let callbacks = &mut self.0.write().unwrap().callbacks;
+        if let Some(index) = callbacks.iter().position(|x| x.name() == callback.name()) {
+            callbacks.remove(index);
+            debug!(
+                "InputFilterThread: unregister_thread_callback, callback {:?} removed!",
+                callback.name()
+            );
+            return;
+        }
+        error!(
+            "InputFilterThread: unregister_thread_callback, callback {:?} doesn't exist",
+            callback.name()
+        );
+    }
+
+    fn notify_timeout_expired(&self, when_nanos: i64) {
+        let callbacks = &self.0.read().unwrap().callbacks;
+        for callback in callbacks.iter() {
+            callback.notify_timeout_expired(when_nanos);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::input_filter::test_callbacks::TestCallbacks;
+    use crate::input_filter_thread::{
+        test_thread::TestThread, test_thread_callback::TestThreadCallback,
+    };
+
+    #[test]
+    fn test_register_callback_creates_cpp_thread() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let test_thread_callback = TestThreadCallback::new();
+        test_thread.register_thread_callback(test_thread_callback);
+        assert!(test_callbacks.is_thread_created());
+    }
+
+    #[test]
+    fn test_unregister_callback_finishes_cpp_thread() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let test_thread_callback = TestThreadCallback::new();
+        test_thread.register_thread_callback(test_thread_callback.clone());
+        test_thread.unregister_thread_callback(test_thread_callback);
+        assert!(test_callbacks.is_thread_finished());
+    }
+
+    #[test]
+    fn test_notify_timeout_called_after_timeout_expired() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let test_thread_callback = TestThreadCallback::new();
+        test_thread.register_thread_callback(test_thread_callback.clone());
+        test_thread.start_looper();
+
+        test_thread.request_timeout_at_time(500);
+        test_thread.dispatch_next();
+
+        test_thread.move_time_forward(500);
+
+        test_thread.stop_looper();
+        assert!(test_thread_callback.is_notify_timeout_called());
+    }
+
+    #[test]
+    fn test_notify_timeout_not_called_before_timeout_expired() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let test_thread_callback = TestThreadCallback::new();
+        test_thread.register_thread_callback(test_thread_callback.clone());
+        test_thread.start_looper();
+
+        test_thread.request_timeout_at_time(500);
+        test_thread.dispatch_next();
+
+        test_thread.move_time_forward(100);
+
+        test_thread.stop_looper();
+        assert!(!test_thread_callback.is_notify_timeout_called());
+    }
+}
+
+#[cfg(test)]
+pub mod test_thread {
+
+    use crate::input_filter::{test_callbacks::TestCallbacks, InputFilterThreadCreator};
+    use crate::input_filter_thread::{test_thread_callback::TestThreadCallback, InputFilterThread};
+    use binder::Strong;
+    use std::sync::{
+        atomic::AtomicBool, atomic::AtomicI64, atomic::Ordering, Arc, RwLock, RwLockWriteGuard,
+    };
+    use std::time::Duration;
+
+    #[derive(Clone)]
+    pub struct TestThread {
+        input_thread: InputFilterThread,
+        inner: Arc<RwLock<TestThreadInner>>,
+        exit_flag: Arc<AtomicBool>,
+        now: Arc<AtomicI64>,
+    }
+
+    struct TestThreadInner {
+        join_handle: Option<std::thread::JoinHandle<()>>,
+    }
+
+    impl TestThread {
+        pub fn new(callbacks: TestCallbacks) -> TestThread {
+            Self {
+                input_thread: InputFilterThread::new(InputFilterThreadCreator::new(Arc::new(
+                    RwLock::new(Strong::new(Box::new(callbacks))),
+                ))),
+                inner: Arc::new(RwLock::new(TestThreadInner { join_handle: None })),
+                exit_flag: Arc::new(AtomicBool::new(false)),
+                now: Arc::new(AtomicI64::new(0)),
+            }
+        }
+
+        fn inner(&self) -> RwLockWriteGuard<'_, TestThreadInner> {
+            self.inner.write().unwrap()
+        }
+
+        pub fn get_input_thread(&self) -> InputFilterThread {
+            self.input_thread.clone()
+        }
+
+        pub fn register_thread_callback(&self, thread_callback: TestThreadCallback) {
+            self.input_thread.register_thread_callback(Box::new(thread_callback));
+        }
+
+        pub fn unregister_thread_callback(&self, thread_callback: TestThreadCallback) {
+            self.input_thread.unregister_thread_callback(Box::new(thread_callback));
+        }
+
+        pub fn start_looper(&self) {
+            self.exit_flag.store(false, Ordering::Relaxed);
+            let clone = self.clone();
+            let join_handle = std::thread::Builder::new()
+                .name("test_thread".to_string())
+                .spawn(move || {
+                    while !clone.exit_flag.load(Ordering::Relaxed) {
+                        clone.loop_once();
+                    }
+                })
+                .unwrap();
+            self.inner().join_handle = Some(join_handle);
+            // Sleep until the looper thread starts
+            std::thread::sleep(Duration::from_millis(10));
+        }
+
+        pub fn stop_looper(&self) {
+            self.exit_flag.store(true, Ordering::Relaxed);
+            {
+                let mut inner = self.inner();
+                if let Some(join_handle) = &inner.join_handle {
+                    join_handle.thread().unpark();
+                }
+                inner.join_handle.take().map(std::thread::JoinHandle::join);
+                inner.join_handle = None;
+            }
+            self.exit_flag.store(false, Ordering::Relaxed);
+        }
+
+        pub fn move_time_forward(&self, value: i64) {
+            let _ = self.now.fetch_add(value, Ordering::Relaxed);
+            self.dispatch_next();
+        }
+
+        pub fn dispatch_next(&self) {
+            if let Some(join_handle) = &self.inner().join_handle {
+                join_handle.thread().unpark();
+            }
+            // Sleep until the looper thread runs a loop
+            std::thread::sleep(Duration::from_millis(10));
+        }
+
+        fn loop_once(&self) {
+            self.input_thread.loop_once(self.now.load(Ordering::Relaxed));
+        }
+
+        pub fn request_timeout_at_time(&self, when_nanos: i64) {
+            self.input_thread.request_timeout_at_time(when_nanos);
+        }
+    }
+}
+
+#[cfg(test)]
+pub mod test_thread_callback {
+    use crate::input_filter_thread::ThreadCallback;
+    use std::sync::{Arc, RwLock, RwLockWriteGuard};
+
+    #[derive(Default)]
+    struct TestThreadCallbackInner {
+        is_notify_timeout_called: bool,
+    }
+
+    #[derive(Default, Clone)]
+    pub struct TestThreadCallback(Arc<RwLock<TestThreadCallbackInner>>);
+
+    impl TestThreadCallback {
+        pub fn new() -> Self {
+            Default::default()
+        }
+
+        fn inner(&self) -> RwLockWriteGuard<'_, TestThreadCallbackInner> {
+            self.0.write().unwrap()
+        }
+
+        pub fn is_notify_timeout_called(&self) -> bool {
+            self.0.read().unwrap().is_notify_timeout_called
+        }
+    }
+
+    impl ThreadCallback for TestThreadCallback {
+        fn notify_timeout_expired(&self, _when_nanos: i64) {
+            self.inner().is_notify_timeout_called = true;
+        }
+        fn name(&self) -> &str {
+            "TestThreadCallback"
+        }
+    }
+}
diff --git a/services/inputflinger/rust/lib.rs b/services/inputflinger/rust/lib.rs
index fa16898835..da72134065 100644
--- a/services/inputflinger/rust/lib.rs
+++ b/services/inputflinger/rust/lib.rs
@@ -21,6 +21,8 @@
 
 mod bounce_keys_filter;
 mod input_filter;
+mod input_filter_thread;
+mod slow_keys_filter;
 mod sticky_keys_filter;
 
 use crate::input_filter::InputFilter;
diff --git a/services/inputflinger/rust/slow_keys_filter.rs b/services/inputflinger/rust/slow_keys_filter.rs
new file mode 100644
index 0000000000..01165b57fa
--- /dev/null
+++ b/services/inputflinger/rust/slow_keys_filter.rs
@@ -0,0 +1,382 @@
+/*
+ * 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.
+ */
+
+//! Slow keys input filter implementation.
+//! Slow keys is an accessibility feature to aid users who have physical disabilities, that allows
+//! the user to specify the duration for which one must press-and-hold a key before the system
+//! accepts the keypress.
+use crate::input_filter::Filter;
+use crate::input_filter_thread::{InputFilterThread, ThreadCallback};
+use android_hardware_input_common::aidl::android::hardware::input::common::Source::Source;
+use com_android_server_inputflinger::aidl::com::android::server::inputflinger::{
+    DeviceInfo::DeviceInfo, KeyEvent::KeyEvent, KeyEventAction::KeyEventAction,
+};
+use log::debug;
+use std::collections::HashSet;
+use std::sync::{Arc, RwLock, RwLockReadGuard, RwLockWriteGuard};
+
+#[derive(Debug)]
+struct OngoingKeyDown {
+    scancode: i32,
+    device_id: i32,
+    down_time: i64,
+}
+
+struct SlowKeysFilterInner {
+    next: Box<dyn Filter + Send + Sync>,
+    slow_key_threshold_ns: i64,
+    external_devices: HashSet<i32>,
+    // This tracks KeyEvents that are blocked by Slow keys filter and will be passed through if the
+    // press duration exceeds the slow keys threshold.
+    pending_down_events: Vec<KeyEvent>,
+    // This tracks KeyEvent streams that have press duration greater than the slow keys threshold,
+    // hence any future ACTION_DOWN (if repeats are handled on HW side) or ACTION_UP are allowed to
+    // pass through without waiting.
+    ongoing_down_events: Vec<OngoingKeyDown>,
+    input_filter_thread: InputFilterThread,
+}
+
+#[derive(Clone)]
+pub struct SlowKeysFilter(Arc<RwLock<SlowKeysFilterInner>>);
+
+impl SlowKeysFilter {
+    /// Create a new SlowKeysFilter instance.
+    pub fn new(
+        next: Box<dyn Filter + Send + Sync>,
+        slow_key_threshold_ns: i64,
+        input_filter_thread: InputFilterThread,
+    ) -> SlowKeysFilter {
+        let filter = Self(Arc::new(RwLock::new(SlowKeysFilterInner {
+            next,
+            slow_key_threshold_ns,
+            external_devices: HashSet::new(),
+            pending_down_events: Vec::new(),
+            ongoing_down_events: Vec::new(),
+            input_filter_thread: input_filter_thread.clone(),
+        })));
+        input_filter_thread.register_thread_callback(Box::new(filter.clone()));
+        filter
+    }
+
+    fn read_inner(&self) -> RwLockReadGuard<'_, SlowKeysFilterInner> {
+        self.0.read().unwrap()
+    }
+
+    fn write_inner(&self) -> RwLockWriteGuard<'_, SlowKeysFilterInner> {
+        self.0.write().unwrap()
+    }
+
+    fn request_next_callback(&self) {
+        let slow_filter = &self.read_inner();
+        if slow_filter.pending_down_events.is_empty() {
+            return;
+        }
+        if let Some(event) = slow_filter.pending_down_events.iter().min_by_key(|x| x.downTime) {
+            slow_filter.input_filter_thread.request_timeout_at_time(event.downTime);
+        }
+    }
+}
+
+impl Filter for SlowKeysFilter {
+    fn notify_key(&mut self, event: &KeyEvent) {
+        {
+            // acquire write lock
+            let mut slow_filter = self.write_inner();
+            if !(slow_filter.external_devices.contains(&event.deviceId)
+                && event.source == Source::KEYBOARD)
+            {
+                slow_filter.next.notify_key(event);
+                return;
+            }
+            // Pass all events through if key down has already been processed
+            // Do update the downtime before sending the events through
+            if let Some(index) = slow_filter
+                .ongoing_down_events
+                .iter()
+                .position(|x| x.device_id == event.deviceId && x.scancode == event.scanCode)
+            {
+                let mut new_event = *event;
+                new_event.downTime = slow_filter.ongoing_down_events[index].down_time;
+                slow_filter.next.notify_key(&new_event);
+                if event.action == KeyEventAction::UP {
+                    slow_filter.ongoing_down_events.remove(index);
+                }
+                return;
+            }
+            match event.action {
+                KeyEventAction::DOWN => {
+                    if slow_filter
+                        .pending_down_events
+                        .iter()
+                        .any(|x| x.deviceId == event.deviceId && x.scanCode == event.scanCode)
+                    {
+                        debug!("Dropping key down event since another pending down event exists");
+                        return;
+                    }
+                    let mut pending_event = *event;
+                    pending_event.downTime += slow_filter.slow_key_threshold_ns;
+                    pending_event.eventTime = pending_event.downTime;
+                    slow_filter.pending_down_events.push(pending_event);
+                }
+                KeyEventAction::UP => {
+                    debug!("Dropping key up event due to insufficient press duration");
+                    if let Some(index) = slow_filter
+                        .pending_down_events
+                        .iter()
+                        .position(|x| x.deviceId == event.deviceId && x.scanCode == event.scanCode)
+                    {
+                        slow_filter.pending_down_events.remove(index);
+                    }
+                }
+                _ => (),
+            }
+        } // release write lock
+        self.request_next_callback();
+    }
+
+    fn notify_devices_changed(&mut self, device_infos: &[DeviceInfo]) {
+        let mut slow_filter = self.write_inner();
+        slow_filter
+            .pending_down_events
+            .retain(|event| device_infos.iter().any(|x| event.deviceId == x.deviceId));
+        slow_filter
+            .ongoing_down_events
+            .retain(|event| device_infos.iter().any(|x| event.device_id == x.deviceId));
+        slow_filter.external_devices.clear();
+        for device_info in device_infos {
+            if device_info.external {
+                slow_filter.external_devices.insert(device_info.deviceId);
+            }
+        }
+        slow_filter.next.notify_devices_changed(device_infos);
+    }
+
+    fn destroy(&mut self) {
+        let mut slow_filter = self.write_inner();
+        slow_filter.input_filter_thread.unregister_thread_callback(Box::new(self.clone()));
+        slow_filter.next.destroy();
+    }
+}
+
+impl ThreadCallback for SlowKeysFilter {
+    fn notify_timeout_expired(&self, when_nanos: i64) {
+        {
+            // acquire write lock
+            let slow_filter = &mut self.write_inner();
+            for event in slow_filter.pending_down_events.clone() {
+                if event.downTime <= when_nanos {
+                    slow_filter.next.notify_key(&event);
+                    slow_filter.ongoing_down_events.push(OngoingKeyDown {
+                        scancode: event.scanCode,
+                        device_id: event.deviceId,
+                        down_time: event.downTime,
+                    });
+                }
+            }
+            slow_filter.pending_down_events.retain(|event| event.downTime > when_nanos);
+        } // release write lock
+        self.request_next_callback();
+    }
+
+    fn name(&self) -> &str {
+        "slow_keys_filter"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::input_filter::{test_callbacks::TestCallbacks, test_filter::TestFilter, Filter};
+    use crate::input_filter_thread::test_thread::TestThread;
+    use crate::slow_keys_filter::SlowKeysFilter;
+    use android_hardware_input_common::aidl::android::hardware::input::common::Source::Source;
+    use com_android_server_inputflinger::aidl::com::android::server::inputflinger::{
+        DeviceInfo::DeviceInfo, KeyEvent::KeyEvent, KeyEventAction::KeyEventAction,
+    };
+
+    static BASE_KEY_EVENT: KeyEvent = KeyEvent {
+        id: 1,
+        deviceId: 1,
+        downTime: 0,
+        readTime: 0,
+        eventTime: 0,
+        source: Source::KEYBOARD,
+        displayId: 0,
+        policyFlags: 0,
+        action: KeyEventAction::DOWN,
+        flags: 0,
+        keyCode: 1,
+        scanCode: 0,
+        metaState: 0,
+    };
+
+    #[test]
+    fn test_is_notify_key_for_internal_keyboard_not_blocked() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let next = TestFilter::new();
+        let mut filter = setup_filter_with_internal_device(
+            Box::new(next.clone()),
+            test_thread.clone(),
+            1,   /* device_id */
+            100, /* threshold */
+        );
+        test_thread.start_looper();
+
+        let event = KeyEvent { action: KeyEventAction::DOWN, ..BASE_KEY_EVENT };
+        filter.notify_key(&event);
+        assert_eq!(next.last_event().unwrap(), event);
+    }
+
+    #[test]
+    fn test_is_notify_key_for_external_stylus_not_blocked() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let next = TestFilter::new();
+        let mut filter = setup_filter_with_external_device(
+            Box::new(next.clone()),
+            test_thread.clone(),
+            1,   /* device_id */
+            100, /* threshold */
+        );
+        test_thread.start_looper();
+
+        let event =
+            KeyEvent { action: KeyEventAction::DOWN, source: Source::STYLUS, ..BASE_KEY_EVENT };
+        filter.notify_key(&event);
+        assert_eq!(next.last_event().unwrap(), event);
+    }
+
+    #[test]
+    fn test_notify_key_for_external_keyboard_when_key_pressed_for_threshold_time() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let next = TestFilter::new();
+        let mut filter = setup_filter_with_external_device(
+            Box::new(next.clone()),
+            test_thread.clone(),
+            1,   /* device_id */
+            100, /* threshold */
+        );
+        test_thread.start_looper();
+
+        filter.notify_key(&KeyEvent { action: KeyEventAction::DOWN, ..BASE_KEY_EVENT });
+        assert!(next.last_event().is_none());
+        test_thread.dispatch_next();
+
+        test_thread.move_time_forward(100);
+
+        test_thread.stop_looper();
+        assert_eq!(
+            next.last_event().unwrap(),
+            KeyEvent {
+                action: KeyEventAction::DOWN,
+                downTime: 100,
+                eventTime: 100,
+                ..BASE_KEY_EVENT
+            }
+        );
+    }
+
+    #[test]
+    fn test_notify_key_for_external_keyboard_when_key_not_pressed_for_threshold_time() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let next = TestFilter::new();
+        let mut filter = setup_filter_with_external_device(
+            Box::new(next.clone()),
+            test_thread.clone(),
+            1,   /* device_id */
+            100, /* threshold */
+        );
+        test_thread.start_looper();
+
+        filter.notify_key(&KeyEvent { action: KeyEventAction::DOWN, ..BASE_KEY_EVENT });
+        test_thread.dispatch_next();
+
+        test_thread.move_time_forward(10);
+
+        filter.notify_key(&KeyEvent { action: KeyEventAction::UP, ..BASE_KEY_EVENT });
+        test_thread.dispatch_next();
+
+        test_thread.stop_looper();
+        assert!(next.last_event().is_none());
+    }
+
+    #[test]
+    fn test_notify_key_for_external_keyboard_when_device_removed_before_threshold_time() {
+        let test_callbacks = TestCallbacks::new();
+        let test_thread = TestThread::new(test_callbacks.clone());
+        let next = TestFilter::new();
+        let mut filter = setup_filter_with_external_device(
+            Box::new(next.clone()),
+            test_thread.clone(),
+            1,   /* device_id */
+            100, /* threshold */
+        );
+        test_thread.start_looper();
+
+        filter.notify_key(&KeyEvent { action: KeyEventAction::DOWN, ..BASE_KEY_EVENT });
+        assert!(next.last_event().is_none());
+        test_thread.dispatch_next();
+
+        filter.notify_devices_changed(&[]);
+        test_thread.dispatch_next();
+
+        test_thread.move_time_forward(100);
+
+        test_thread.stop_looper();
+        assert!(next.last_event().is_none());
+    }
+
+    fn setup_filter_with_external_device(
+        next: Box<dyn Filter + Send + Sync>,
+        test_thread: TestThread,
+        device_id: i32,
+        threshold: i64,
+    ) -> SlowKeysFilter {
+        setup_filter_with_devices(
+            next,
+            test_thread,
+            &[DeviceInfo { deviceId: device_id, external: true }],
+            threshold,
+        )
+    }
+
+    fn setup_filter_with_internal_device(
+        next: Box<dyn Filter + Send + Sync>,
+        test_thread: TestThread,
+        device_id: i32,
+        threshold: i64,
+    ) -> SlowKeysFilter {
+        setup_filter_with_devices(
+            next,
+            test_thread,
+            &[DeviceInfo { deviceId: device_id, external: false }],
+            threshold,
+        )
+    }
+
+    fn setup_filter_with_devices(
+        next: Box<dyn Filter + Send + Sync>,
+        test_thread: TestThread,
+        devices: &[DeviceInfo],
+        threshold: i64,
+    ) -> SlowKeysFilter {
+        let mut filter = SlowKeysFilter::new(next, threshold, test_thread.get_input_thread());
+        filter.notify_devices_changed(devices);
+        filter
+    }
+}
diff --git a/services/inputflinger/rust/sticky_keys_filter.rs b/services/inputflinger/rust/sticky_keys_filter.rs
index da581b82bf..6c2277c813 100644
--- a/services/inputflinger/rust/sticky_keys_filter.rs
+++ b/services/inputflinger/rust/sticky_keys_filter.rs
@@ -142,6 +142,10 @@ impl Filter for StickyKeysFilter {
         }
         self.next.notify_devices_changed(device_infos);
     }
+
+    fn destroy(&mut self) {
+        self.next.destroy();
+    }
 }
 
 fn is_modifier_key(keycode: i32) -> bool {