Improve BlockingQueue and add SyncQueue
Changes to BlockingQueue:
- Change BlockingQueue to be list-backed instead of vector-backed so
that removals are O(1) instead of O(N).
- Rename erase to erase_if.
- Make providing a fixed capacity at construction optional.
- Add emplace function to push and construct element in-place.
- Add popWithTimeout function.
Bug: 275726706
Test: atest inputflinger_tests
Change-Id: I1be02b0887df2c21b28f4f1cb43a8e208d996a87
diff --git a/services/inputflinger/BlockingQueue.h b/services/inputflinger/BlockingQueue.h
index fe37287..5693848 100644
--- a/services/inputflinger/BlockingQueue.h
+++ b/services/inputflinger/BlockingQueue.h
@@ -16,15 +16,17 @@
#pragma once
-#include "android-base/thread_annotations.h"
#include <condition_variable>
+#include <list>
#include <mutex>
-#include <vector>
+#include <optional>
+#include "android-base/thread_annotations.h"
namespace android {
/**
- * A FIFO queue that stores up to <i>capacity</i> objects.
+ * A thread-safe FIFO queue. This list-backed queue stores up to <i>capacity</i> objects if
+ * a capacity is provided at construction, and is otherwise unbounded.
* Objects can always be added. Objects are added immediately.
* If the queue is full, new objects cannot be added.
*
@@ -33,13 +35,13 @@
template <class T>
class BlockingQueue {
public:
- BlockingQueue(size_t capacity) : mCapacity(capacity) {
- mQueue.reserve(mCapacity);
- };
+ explicit BlockingQueue() = default;
+
+ explicit BlockingQueue(size_t capacity) : mCapacity(capacity){};
/**
* Retrieve and remove the oldest object.
- * Blocks execution while queue is empty.
+ * Blocks execution indefinitely while queue is empty.
*/
T pop() {
std::unique_lock lock(mLock);
@@ -51,26 +53,62 @@
};
/**
+ * Retrieve and remove the oldest object.
+ * Blocks execution for the given duration while queue is empty, and returns std::nullopt
+ * if the queue was empty for the entire duration.
+ */
+ std::optional<T> popWithTimeout(std::chrono::nanoseconds duration) {
+ std::unique_lock lock(mLock);
+ android::base::ScopedLockAssertion assumeLock(mLock);
+ if (!mHasElements.wait_for(lock, duration,
+ [this]() REQUIRES(mLock) { return !this->mQueue.empty(); })) {
+ return {};
+ }
+ T t = std::move(mQueue.front());
+ mQueue.erase(mQueue.begin());
+ return t;
+ };
+
+ /**
* Add a new object to the queue.
* Does not block.
* Return true if an element was successfully added.
* Return false if the queue is full.
*/
bool push(T&& t) {
- {
+ { // acquire lock
std::scoped_lock lock(mLock);
- if (mQueue.size() == mCapacity) {
+ if (mCapacity && mQueue.size() == mCapacity) {
return false;
}
mQueue.push_back(std::move(t));
- }
+ } // release lock
mHasElements.notify_one();
return true;
};
- void erase(const std::function<bool(const T&)>& lambda) {
+ /**
+ * Construct a new object into the queue.
+ * Does not block.
+ * Return true if an element was successfully added.
+ * Return false if the queue is full.
+ */
+ template <class... Args>
+ bool emplace(Args&&... args) {
+ { // acquire lock
+ std::scoped_lock lock(mLock);
+ if (mCapacity && mQueue.size() == mCapacity) {
+ return false;
+ }
+ mQueue.emplace_back(args...);
+ } // release lock
+ mHasElements.notify_one();
+ return true;
+ };
+
+ void erase_if(const std::function<bool(const T&)>& pred) {
std::scoped_lock lock(mLock);
- std::erase_if(mQueue, [&lambda](const auto& t) { return lambda(t); });
+ std::erase_if(mQueue, pred);
}
/**
@@ -93,7 +131,7 @@
}
private:
- const size_t mCapacity;
+ const std::optional<size_t> mCapacity;
/**
* Used to signal that mQueue is non-empty.
*/
@@ -102,7 +140,7 @@
* Lock for accessing and waiting on elements.
*/
std::mutex mLock;
- std::vector<T> mQueue GUARDED_BY(mLock);
+ std::list<T> mQueue GUARDED_BY(mLock);
};
} // namespace android
diff --git a/services/inputflinger/InputProcessor.cpp b/services/inputflinger/InputProcessor.cpp
index 7a84be9..6dd267c 100644
--- a/services/inputflinger/InputProcessor.cpp
+++ b/services/inputflinger/InputProcessor.cpp
@@ -322,7 +322,7 @@
void MotionClassifier::reset(const NotifyDeviceResetArgs& args) {
int32_t deviceId = args.deviceId;
// Clear the pending events right away, to avoid unnecessary work done by the HAL.
- mEvents.erase([deviceId](const ClassifierEvent& event) {
+ mEvents.erase_if([deviceId](const ClassifierEvent& event) {
std::optional<int32_t> eventDeviceId = event.getDeviceId();
return eventDeviceId && (*eventDeviceId == deviceId);
});
diff --git a/services/inputflinger/SyncQueue.h b/services/inputflinger/SyncQueue.h
new file mode 100644
index 0000000..62efd55
--- /dev/null
+++ b/services/inputflinger/SyncQueue.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright 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 <utils/threads.h>
+#include <list>
+#include <mutex>
+#include <optional>
+
+namespace android {
+
+/** A thread-safe FIFO queue. */
+template <class T>
+class SyncQueue {
+public:
+ /** Retrieve and remove the oldest object. Returns std::nullopt if the queue is empty. */
+ std::optional<T> pop() {
+ std::scoped_lock lock(mLock);
+ if (mQueue.empty()) {
+ return {};
+ }
+ T t = std::move(mQueue.front());
+ mQueue.erase(mQueue.begin());
+ return t;
+ };
+
+ /** Add a new object to the queue. */
+ template <class... Args>
+ void push(Args&&... args) {
+ std::scoped_lock lock(mLock);
+ mQueue.emplace_back(args...);
+ };
+
+private:
+ std::mutex mLock;
+ std::list<T> mQueue GUARDED_BY(mLock);
+};
+
+} // namespace android
diff --git a/services/inputflinger/tests/Android.bp b/services/inputflinger/tests/Android.bp
index ec67a1d..94b3666 100644
--- a/services/inputflinger/tests/Android.bp
+++ b/services/inputflinger/tests/Android.bp
@@ -58,6 +58,7 @@
"NotifyArgs_test.cpp",
"PreferStylusOverTouch_test.cpp",
"PropertyProvider_test.cpp",
+ "SyncQueue_test.cpp",
"TestInputListener.cpp",
"UinputDevice.cpp",
"UnwantedInteractionBlocker_test.cpp",
diff --git a/services/inputflinger/tests/BlockingQueue_test.cpp b/services/inputflinger/tests/BlockingQueue_test.cpp
index fd9d9d5..754a5c4 100644
--- a/services/inputflinger/tests/BlockingQueue_test.cpp
+++ b/services/inputflinger/tests/BlockingQueue_test.cpp
@@ -22,6 +22,7 @@
namespace android {
+using std::chrono_literals::operator""ns;
// --- BlockingQueueTest ---
@@ -34,6 +35,14 @@
ASSERT_TRUE(queue.push(1));
ASSERT_EQ(queue.pop(), 1);
+
+ ASSERT_TRUE(queue.emplace(2));
+ ASSERT_EQ(queue.popWithTimeout(0ns), 2);
+
+ ASSERT_TRUE(queue.push(3));
+ ASSERT_EQ(queue.popWithTimeout(100ns), 3);
+
+ ASSERT_EQ(std::nullopt, queue.popWithTimeout(0ns));
}
/**
@@ -87,7 +96,7 @@
queue.push(3);
queue.push(4);
// Erase elements 2 and 4
- queue.erase([](int element) { return element == 2 || element == 4; });
+ queue.erase_if([](int element) { return element == 2 || element == 4; });
// Should no longer receive elements 2 and 4
ASSERT_EQ(1, queue.pop());
ASSERT_EQ(3, queue.pop());
@@ -138,5 +147,9 @@
ASSERT_TRUE(hasReceivedElement);
}
+TEST(BlockingQueueTest, Queue_TimesOut) {
+ BlockingQueue<int> queue;
+ ASSERT_EQ(std::nullopt, queue.popWithTimeout(1ns));
+}
} // namespace android
diff --git a/services/inputflinger/tests/SyncQueue_test.cpp b/services/inputflinger/tests/SyncQueue_test.cpp
new file mode 100644
index 0000000..af2f961
--- /dev/null
+++ b/services/inputflinger/tests/SyncQueue_test.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright 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.
+ */
+
+#include "../SyncQueue.h"
+
+#include <gtest/gtest.h>
+#include <thread>
+
+namespace android {
+
+// --- SyncQueueTest ---
+
+// Validate basic pop and push operation.
+TEST(SyncQueueTest, AddAndRemove) {
+ SyncQueue<int> queue;
+
+ queue.push(1);
+ ASSERT_EQ(queue.pop(), 1);
+
+ queue.push(3);
+ ASSERT_EQ(queue.pop(), 3);
+
+ ASSERT_EQ(std::nullopt, queue.pop());
+}
+
+// Make sure the queue maintains FIFO order.
+// Add elements and remove them, and check the order.
+TEST(SyncQueueTest, isFIFO) {
+ SyncQueue<int> queue;
+
+ constexpr int numItems = 10;
+ for (int i = 0; i < numItems; i++) {
+ queue.push(static_cast<int>(i));
+ }
+ for (int i = 0; i < numItems; i++) {
+ ASSERT_EQ(queue.pop(), static_cast<int>(i));
+ }
+}
+
+TEST(SyncQueueTest, AllowsMultipleThreads) {
+ SyncQueue<int> queue;
+
+ // Test with a large number of items to increase likelihood that threads overlap
+ constexpr int numItems = 100;
+
+ // Fill queue from a different thread
+ std::thread fillQueue([&queue]() {
+ for (int i = 0; i < numItems; i++) {
+ queue.push(static_cast<int>(i));
+ }
+ });
+
+ // Make sure all elements are received in correct order
+ for (int i = 0; i < numItems; i++) {
+ // Since popping races with the thread that's filling the queue,
+ // keep popping until we get something back
+ std::optional<int> popped;
+ do {
+ popped = queue.pop();
+ } while (!popped);
+ ASSERT_EQ(popped, static_cast<int>(i));
+ }
+
+ fillQueue.join();
+}
+
+} // namespace android
diff --git a/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp b/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp
index d2595bf..e9016bb 100644
--- a/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp
+++ b/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp
@@ -47,12 +47,21 @@
filled > numPops ? filled -= numPops : filled = 0;
},
[&]() -> void {
+ // Pops blocks if it is empty, so only pop up to num elements inserted.
+ size_t numPops = fdp.ConsumeIntegralInRange<size_t>(0, filled);
+ for (size_t i = 0; i < numPops; i++) {
+ queue.popWithTimeout(
+ std::chrono::nanoseconds{fdp.ConsumeIntegral<int64_t>()});
+ }
+ filled > numPops ? filled -= numPops : filled = 0;
+ },
+ [&]() -> void {
queue.clear();
filled = 0;
},
[&]() -> void {
int32_t eraseElement = fdp.ConsumeIntegral<int32_t>();
- queue.erase([&](int32_t element) {
+ queue.erase_if([&](int32_t element) {
if (element == eraseElement) {
filled--;
return true;