// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chromeos/dbus/common/pipe_reader.h"

#include <memory>
#include <optional>
#include <string>
#include <utility>

#include "base/files/file_util.h"
#include "base/files/scoped_file.h"
#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/location.h"
#include "base/memory/ref_counted.h"
#include "base/task/task_runner.h"
#include "base/task/thread_pool.h"
#include "base/test/task_environment.h"
#include "base/test/test_future.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace chromeos {
namespace {

// Writes the |data| to |fd|, then close |fd|.
void WriteData(base::ScopedFD fd, const std::string& data) {
  EXPECT_TRUE(base::WriteFileDescriptor(fd.get(), data));
}

}  // namespace

class PipeReaderTest : public testing::Test {
 public:
  PipeReaderTest() = default;
  ~PipeReaderTest() override {
    // Flush the TaskEnvironment to prevent leaks of PostTaskAndReply
    // callbacks.
    task_environment_.RunUntilIdle();
  }

  scoped_refptr<base::TaskRunner> GetTaskRunner() {
    return task_environment_.GetMainThreadTaskRunner();
  }

 private:
  base::test::TaskEnvironment task_environment_;
};

TEST_F(PipeReaderTest, Empty) {
  auto reader = std::make_unique<PipeReader>(GetTaskRunner());
  base::test::TestFuture<std::optional<std::string>> output_test_future;
  base::ScopedFD write_fd = reader->StartIO(output_test_future.GetCallback());
  write_fd.reset();
  EXPECT_EQ(std::string(), output_test_future.Get());
}

TEST_F(PipeReaderTest, SmallData) {
  constexpr char kSmallData[] = "abcdefghijklmnopqrstuvwxyz";

  auto reader = std::make_unique<PipeReader>(GetTaskRunner());
  base::test::TestFuture<std::optional<std::string>> output_test_future;
  base::ScopedFD write_fd = reader->StartIO(output_test_future.GetCallback());
  base::ThreadPool::PostTask(
      FROM_HERE, base::BindOnce(&WriteData, std::move(write_fd), kSmallData));
  EXPECT_EQ(std::string(kSmallData), output_test_future.Get());
}

TEST_F(PipeReaderTest, LargeData) {
  // Larger than internal buffer size (=4096 bytes).
  const std::string large_data(8192, 'a');

  auto reader = std::make_unique<PipeReader>(GetTaskRunner());
  base::test::TestFuture<std::optional<std::string>> output_test_future;
  base::ScopedFD write_fd = reader->StartIO(output_test_future.GetCallback());
  base::ThreadPool::PostTask(
      FROM_HERE, base::BindOnce(&WriteData, std::move(write_fd), large_data));
  EXPECT_EQ(large_data, output_test_future.Get());
}

TEST_F(PipeReaderTest, Cancel) {
  auto reader = std::make_unique<PipeReader>(GetTaskRunner());
  base::ScopedFD write_fd =
      reader->StartIO(base::BindOnce([](std::optional<std::string> result) {
        FAIL();  // Unexpected to be called.
      }));
  reader.reset();  // Delete |reader| before closing |write_fd|.
}

}  // namespace chromeos