1 files changed, 248 insertions, 0 deletions
diff --git a/mfbt/tests/TestSPSCQueue.cpp b/mfbt/tests/TestSPSCQueue.cpp
new file mode 100644
index 0000000000..d114fe72a9
--- /dev/null
+++ b/mfbt/tests/TestSPSCQueue.cpp
@@ -0,0 +1,248 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/SPSCQueue.h"
+#include "mozilla/PodOperations.h"
+#include <vector>
+#include <iostream>
+#include <thread>
+#include <chrono>
+#include <memory>
+#include <string>
+
+#ifdef _WIN32
+#  include <windows.h>
+#endif
+
+using namespace mozilla;
+
+/* Generate a monotonically increasing sequence of numbers. */
+template <typename T>
+class SequenceGenerator {
+ public:
+  SequenceGenerator() = default;
+  void Get(T* aElements, size_t aCount) {
+    for (size_t i = 0; i < aCount; i++) {
+      aElements[i] = static_cast<T>(mIndex);
+      mIndex++;
+    }
+  }
+  void Rewind(size_t aCount) { mIndex -= aCount; }
+
+ private:
+  size_t mIndex = 0;
+};
+
+/* Checks that a sequence is monotonically increasing. */
+template <typename T>
+class SequenceVerifier {
+ public:
+  SequenceVerifier() = default;
+  void Check(T* aElements, size_t aCount) {
+    for (size_t i = 0; i < aCount; i++) {
+      if (aElements[i] != static_cast<T>(mIndex)) {
+        std::cerr << "Element " << i << " is different. Expected "
+                  << static_cast<T>(mIndex) << ", got " << aElements[i] << "."
+                  << std::endl;
+        MOZ_RELEASE_ASSERT(false);
+      }
+      mIndex++;
+    }
+  }
+
+ private:
+  size_t mIndex = 0;
+};
+
+const int BLOCK_SIZE = 127;
+
+template <typename T>
+void TestRing(int capacity) {
+  SPSCQueue<T> buf(capacity);
+  std::unique_ptr<T[]> seq(new T[capacity]);
+  SequenceGenerator<T> gen;
+  SequenceVerifier<T> checker;
+
+  int iterations = 1002;
+
+  while (iterations--) {
+    gen.Get(seq.get(), BLOCK_SIZE);
+    int rv = buf.Enqueue(seq.get(), BLOCK_SIZE);
+    MOZ_RELEASE_ASSERT(rv == BLOCK_SIZE);
+    PodZero(seq.get(), BLOCK_SIZE);
+    rv = buf.Dequeue(seq.get(), BLOCK_SIZE);
+    MOZ_RELEASE_ASSERT(rv == BLOCK_SIZE);
+    checker.Check(seq.get(), BLOCK_SIZE);
+  }
+}
+
+void Delay() {
+  // On Windows and x86 Android, the timer resolution is so bad that, even if
+  // we used `timeBeginPeriod(1)`, any nonzero sleep from the test's inner loops
+  // would make this program take far too long.
+#ifdef _WIN32
+  Sleep(0);
+#elif defined(ANDROID)
+  std::this_thread::sleep_for(std::chrono::microseconds(0));
+#else
+  std::this_thread::sleep_for(std::chrono::microseconds(10));
+#endif
+}
+
+template <typename T>
+void TestRingMultiThread(int capacity) {
+  SPSCQueue<T> buf(capacity);
+  SequenceVerifier<T> checker;
+  std::unique_ptr<T[]> outBuffer(new T[capacity]);
+
+  std::thread t([&buf, capacity] {
+    int iterations = 1002;
+    std::unique_ptr<T[]> inBuffer(new T[capacity]);
+    SequenceGenerator<T> gen;
+
+    while (iterations--) {
+      Delay();
+      gen.Get(inBuffer.get(), BLOCK_SIZE);
+      int rv = buf.Enqueue(inBuffer.get(), BLOCK_SIZE);
+      MOZ_RELEASE_ASSERT(rv <= BLOCK_SIZE);
+      if (rv != BLOCK_SIZE) {
+        gen.Rewind(BLOCK_SIZE - rv);
+      }
+    }
+  });
+
+  int remaining = 1002;
+
+  while (remaining--) {
+    Delay();
+    int rv = buf.Dequeue(outBuffer.get(), BLOCK_SIZE);
+    MOZ_RELEASE_ASSERT(rv <= BLOCK_SIZE);
+    checker.Check(outBuffer.get(), rv);
+  }
+
+  t.join();
+}
+
+template <typename T>
+void BasicAPITest(T& ring) {
+  MOZ_RELEASE_ASSERT(ring.Capacity() == 128);
+
+  MOZ_RELEASE_ASSERT(ring.AvailableRead() == 0);
+  MOZ_RELEASE_ASSERT(ring.AvailableWrite() == 128);
+
+  int rv = ring.EnqueueDefault(63);
+
+  MOZ_RELEASE_ASSERT(rv == 63);
+  MOZ_RELEASE_ASSERT(ring.AvailableRead() == 63);
+  MOZ_RELEASE_ASSERT(ring.AvailableWrite() == 65);
+
+  rv = ring.EnqueueDefault(65);
+
+  MOZ_RELEASE_ASSERT(rv == 65);
+  MOZ_RELEASE_ASSERT(ring.AvailableRead() == 128);
+  MOZ_RELEASE_ASSERT(ring.AvailableWrite() == 0);
+
+  rv = ring.Dequeue(nullptr, 63);
+
+  MOZ_RELEASE_ASSERT(ring.AvailableRead() == 65);
+  MOZ_RELEASE_ASSERT(ring.AvailableWrite() == 63);
+
+  rv = ring.Dequeue(nullptr, 65);
+
+  MOZ_RELEASE_ASSERT(ring.AvailableRead() == 0);
+  MOZ_RELEASE_ASSERT(ring.AvailableWrite() == 128);
+}
+
+const size_t RING_BUFFER_SIZE = 128;
+const size_t ENQUEUE_SIZE = RING_BUFFER_SIZE / 2;
+
+void TestResetAPI() {
+  SPSCQueue<float> ring(RING_BUFFER_SIZE);
+  std::thread t([&ring] {
+    std::unique_ptr<float[]> inBuffer(new float[ENQUEUE_SIZE]);
+    int rv = ring.Enqueue(inBuffer.get(), ENQUEUE_SIZE);
+    MOZ_RELEASE_ASSERT(rv > 0);
+  });
+
+  t.join();
+
+  ring.ResetThreadIds();
+
+  // Enqueue with a different thread. We have reset the thread ID
+  // in the ring buffer, this should work.
+  std::thread t2([&ring] {
+    std::unique_ptr<float[]> inBuffer(new float[ENQUEUE_SIZE]);
+    int rv = ring.Enqueue(inBuffer.get(), ENQUEUE_SIZE);
+    MOZ_RELEASE_ASSERT(rv > 0);
+  });
+
+  t2.join();
+}
+
+void TestMove() {
+  const size_t ELEMENT_COUNT = 16;
+  struct Thing {
+    Thing() : mStr("") {}
+    explicit Thing(const std::string& aStr) : mStr(aStr) {}
+    Thing(Thing&& aOtherThing) {
+      mStr = std::move(aOtherThing.mStr);
+      // aOtherThing.mStr.clear();
+    }
+    Thing& operator=(Thing&& aOtherThing) {
+      mStr = std::move(aOtherThing.mStr);
+      return *this;
+    }
+    std::string mStr;
+  };
+
+  std::vector<Thing> vec_in;
+  std::vector<Thing> vec_out;
+
+  for (uint32_t i = 0; i < ELEMENT_COUNT; i++) {
+    vec_in.push_back(Thing(std::to_string(i)));
+    vec_out.push_back(Thing());
+  }
+
+  SPSCQueue<Thing> queue(ELEMENT_COUNT);
+
+  int rv = queue.Enqueue(&vec_in[0], ELEMENT_COUNT);
+  MOZ_RELEASE_ASSERT(rv == ELEMENT_COUNT);
+
+  // Check that we've moved the std::string into the queue.
+  for (uint32_t i = 0; i < ELEMENT_COUNT; i++) {
+    MOZ_RELEASE_ASSERT(vec_in[i].mStr.empty());
+  }
+
+  rv = queue.Dequeue(&vec_out[0], ELEMENT_COUNT);
+  MOZ_RELEASE_ASSERT(rv == ELEMENT_COUNT);
+
+  for (uint32_t i = 0; i < ELEMENT_COUNT; i++) {
+    MOZ_RELEASE_ASSERT(std::stoul(vec_out[i].mStr) == i);
+  }
+}
+
+int main() {
+  const int minCapacity = 199;
+  const int maxCapacity = 1277;
+  const int capacityIncrement = 27;
+
+  SPSCQueue<float> q1(128);
+  BasicAPITest(q1);
+  SPSCQueue<char> q2(128);
+  BasicAPITest(q2);
+
+  for (uint32_t i = minCapacity; i < maxCapacity; i += capacityIncrement) {
+    TestRing<uint32_t>(i);
+    TestRingMultiThread<uint32_t>(i);
+    TestRing<float>(i);
+    TestRingMultiThread<float>(i);
+  }
+
+  TestResetAPI();
+  TestMove();
+
+  return 0;
+}