DO NOT MERGE Add inputflinger blockingQueue/classifier fuzzers

This CL aims to add libfuzzer fuzzers to inputflinger, to test the
BlockingQueue and InputClassifier objects.

Test: Each fuzzer was tested on a Pixel 3a for a few million
      iterations to ensure stability. Executions/sec average about
      500 for the BlockingQueue fuzzer, and ~2000-2500 for the
      InputClassifier fuzzers.
Signed-off-by: Michael Ensing <michael.ensing@leviathansecurity.com>
Change-Id: If48e5ddbe3066800da88216882ffbbf417dc0d2c
diff --git a/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp b/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp
new file mode 100644
index 0000000..6a136cf
--- /dev/null
+++ b/services/inputflinger/tests/fuzzers/BlockingQueueFuzzer.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright 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 <fuzzer/FuzzedDataProvider.h>
+#include <thread>
+#include "BlockingQueue.h"
+
+// Chosen to be a number large enough for variation in fuzzer runs, but not consume too much memory.
+static constexpr size_t MAX_CAPACITY = 1024;
+
+namespace android {
+
+extern "C" int LLVMFuzzerTestOneInput(uint8_t *data, size_t size) {
+    FuzzedDataProvider fdp(data, size);
+    size_t capacity = fdp.ConsumeIntegralInRange<size_t>(1, MAX_CAPACITY);
+    size_t filled = 0;
+    BlockingQueue<int32_t> queue(capacity);
+
+    while (fdp.remaining_bytes() > 0) {
+        fdp.PickValueInArray<std::function<void()>>({
+                [&]() -> void {
+                    size_t numPushes = fdp.ConsumeIntegralInRange<size_t>(0, capacity + 1);
+                    for (size_t i = 0; i < numPushes; i++) {
+                        queue.push(fdp.ConsumeIntegral<int32_t>());
+                    }
+                    filled = std::min(capacity, filled + numPushes);
+                },
+                [&]() -> 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.pop();
+                    }
+                    filled > numPops ? filled -= numPops : filled = 0;
+                },
+                [&]() -> void {
+                    queue.clear();
+                    filled = 0;
+                },
+                [&]() -> void {
+                    int32_t eraseElement = fdp.ConsumeIntegral<int32_t>();
+                    queue.erase([&](int32_t element) {
+                        if (element == eraseElement) {
+                            filled--;
+                            return true;
+                        }
+                        return false;
+                    });
+                },
+        })();
+    }
+
+    return 0;
+}
+
+} // namespace android