// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "remoting/base/typed_buffer.h"

#include <utility>

#include "base/compiler_specific.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace remoting {

namespace {

struct Data {
  // A variable size vector.
  int data[1];
};

}  // namespace

// Check that the default constructor does not allocate the buffer.
TEST(TypedBufferTest, Empty) {
  TypedBuffer<Data> buffer;
  EXPECT_FALSE(buffer.get());
  EXPECT_FALSE(buffer);
  EXPECT_EQ(buffer.length(), 0u);
}

// Check that allocating zero-size structure does not allocate the buffer.
TEST(TypedBufferTest, ZeroSize) {
  TypedBuffer<Data> buffer(0);
  EXPECT_FALSE(buffer.get());
  EXPECT_FALSE(buffer);
  EXPECT_EQ(buffer.length(), 0u);
}

// Test creation of a buffer and verify that the buffer accessors work.
TEST(TypedBufferTest, Basic) {
  TypedBuffer<Data> buffer(sizeof(int) * 10);
  EXPECT_TRUE(buffer.get());
  EXPECT_TRUE(buffer);
  EXPECT_EQ(buffer.length(), sizeof(int) * 10);

  // Make sure that operator*() syntax works.
  UNSAFE_TODO((*buffer).data[9]) = 0x12345678;

  // Make sure that operator->() syntax works.
  UNSAFE_TODO(EXPECT_EQ(buffer->data[9], 0x12345678));
}

// Test creating a const (reference to) buffer. (This is something of a
// compilation test.)
TEST(TypedBufferTest, ConstTypedBuffer) {
  TypedBuffer<Data> buffer(sizeof(int) * 10);
  ASSERT_THAT(buffer.get(), testing::NotNull());
  (*buffer).data[0] = 0x12345678;
  const auto& buffer_reference = buffer;
  ASSERT_EQ(buffer_reference.get()->data[0], 0x12345678);
}

// Test passing ownership.
TEST(TypedBufferTest, Pass) {
  TypedBuffer<Data> left;
  TypedBuffer<Data> right(sizeof(int));

  EXPECT_FALSE(left.get());
  EXPECT_EQ(left.length(), 0u);
  EXPECT_TRUE(right.get());
  EXPECT_EQ(right.length(), sizeof(int));

  Data* ptr = right.get();
  left = std::move(right);

  // Verify that passing ownership transfers both the buffer pointer and its
  // length.
  EXPECT_EQ(left.get(), ptr);
  EXPECT_EQ(left.length(), sizeof(int));

  // Verify that the original object was cleared.
  EXPECT_FALSE(right.get());
  EXPECT_EQ(right.length(), 0u);
}

// Test swapping ownership.
TEST(TypedBufferTest, Swap) {
  TypedBuffer<Data> left(sizeof(int));
  TypedBuffer<Data> right(sizeof(int) * 2);

  EXPECT_TRUE(left.get());
  EXPECT_EQ(left.length(), sizeof(int));
  EXPECT_TRUE(right.get());
  EXPECT_EQ(right.length(), sizeof(int) * 2);

  Data* raw_left = left.get();
  Data* raw_right = right.get();
  left.Swap(right);

  // Verify that swapping simply exchange contents of two objects.
  // length.
  EXPECT_EQ(left.get(), raw_right);
  EXPECT_EQ(left.length(), sizeof(int) * 2);
  EXPECT_EQ(right.get(), raw_left);
  EXPECT_EQ(right.length(), sizeof(int));
}

}  // namespace remoting