text: //===-- buffer_queue_test.cc ----------------------------------------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file is a part of XRay, a function call tracing system.
  //
  //===----------------------------------------------------------------------===//
  #include "xray_buffer_queue.h"
  #include "gtest/gtest.h"
  
  #include <future>
  #include <system_error>
  #include <unistd.h>
  
  namespace __xray {
  
  static constexpr size_t kSize = 4096;
  
  TEST(BufferQueueTest, API) { BufferQueue Buffers(kSize, 1); }
  
  TEST(BufferQueueTest, GetAndRelease) {
    BufferQueue Buffers(kSize, 1);
    BufferQueue::Buffer Buf;
    ASSERT_EQ(Buffers.getBuffer(Buf), std::error_code());
    ASSERT_NE(nullptr, Buf.Buffer);
    ASSERT_EQ(Buffers.releaseBuffer(Buf), std::error_code());
    ASSERT_EQ(nullptr, Buf.Buffer);
  }
  
  TEST(BufferQueueTest, GetUntilFailed) {
    BufferQueue Buffers(kSize, 1);
    BufferQueue::Buffer Buf0;
    EXPECT_EQ(Buffers.getBuffer(Buf0), std::error_code());
    BufferQueue::Buffer Buf1;
    EXPECT_EQ(std::errc::not_enough_memory, Buffers.getBuffer(Buf1));
    EXPECT_EQ(Buffers.releaseBuffer(Buf0), std::error_code());
  }
  
  TEST(BufferQueueTest, ReleaseUnknown) {
    BufferQueue Buffers(kSize, 1);
    BufferQueue::Buffer Buf;
    Buf.Buffer = reinterpret_cast<void *>(0xdeadbeef);
    Buf.Size = kSize;
    EXPECT_EQ(std::errc::argument_out_of_domain, Buffers.releaseBuffer(Buf));
  }
  
  TEST(BufferQueueTest, ErrorsWhenFinalising) {
    BufferQueue Buffers(kSize, 2);
    BufferQueue::Buffer Buf;
    ASSERT_EQ(Buffers.getBuffer(Buf), std::error_code());
    ASSERT_NE(nullptr, Buf.Buffer);
    ASSERT_EQ(Buffers.finalize(), std::error_code());
    BufferQueue::Buffer OtherBuf;
    ASSERT_EQ(std::errc::state_not_recoverable, Buffers.getBuffer(OtherBuf));
    ASSERT_EQ(std::errc::state_not_recoverable, Buffers.finalize());
    ASSERT_EQ(Buffers.releaseBuffer(Buf), std::error_code());
  }
  
  TEST(BufferQueueTest, MultiThreaded) {
    BufferQueue Buffers(kSize, 100);
    auto F = [&] {
      BufferQueue::Buffer B;
      while (!Buffers.getBuffer(B)) {
        Buffers.releaseBuffer(B);
      }
    };
    auto T0 = std::async(std::launch::async, F);
    auto T1 = std::async(std::launch::async, F);
    auto T2 = std::async(std::launch::async, [&] {
      while (!Buffers.finalize())
        ;
    });
    F();
  }
  
  } // namespace __xray
  