/*
 * Copyright (C) 2013 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 "mem_map.h"

#include "UniquePtr.h"
#include "gtest/gtest.h"

namespace art {

class MemMapTest : public testing::Test {
 public:
  byte* BaseBegin(MemMap* mem_map) {
    return reinterpret_cast<byte*>(mem_map->base_begin_);
  }
  size_t BaseSize(MemMap* mem_map) {
    return mem_map->base_size_;
  }
};

TEST_F(MemMapTest, MapAnonymousEmpty) {
  std::string error_msg;
  UniquePtr<MemMap> map(MemMap::MapAnonymous("MapAnonymousEmpty",
                                             NULL,
                                             0,
                                             PROT_READ,
                                             &error_msg));
  ASSERT_TRUE(map.get() != NULL) << error_msg;
  ASSERT_TRUE(error_msg.empty());
}

TEST_F(MemMapTest, RemapAtEnd) {
  std::string error_msg;
  // Cast the page size to size_t.
  const size_t page_size = static_cast<size_t>(kPageSize);
  // Map a two-page memory region.
  MemMap* m0 = MemMap::MapAnonymous("MemMapTest_RemapAtEndTest_map0",
                                    NULL,
                                    2 * page_size,
                                    PROT_READ | PROT_WRITE,
                                    &error_msg);
  // Check its state and write to it.
  byte* base0 = m0->Begin();
  ASSERT_TRUE(base0 != NULL) << error_msg;
  size_t size0 = m0->Size();
  EXPECT_EQ(m0->Size(), 2 * page_size);
  EXPECT_EQ(BaseBegin(m0), base0);
  EXPECT_EQ(BaseSize(m0), size0);
  memset(base0, 42, 2 * page_size);
  // Remap the latter half into a second MemMap.
  MemMap* m1 = m0->RemapAtEnd(base0 + page_size,
                              "MemMapTest_RemapAtEndTest_map1",
                              PROT_READ | PROT_WRITE,
                              &error_msg);
  // Check the states of the two maps.
  EXPECT_EQ(m0->Begin(), base0) << error_msg;
  EXPECT_EQ(m0->Size(), page_size);
  EXPECT_EQ(BaseBegin(m0), base0);
  EXPECT_EQ(BaseSize(m0), page_size);
  byte* base1 = m1->Begin();
  size_t size1 = m1->Size();
  EXPECT_EQ(base1, base0 + page_size);
  EXPECT_EQ(size1, page_size);
  EXPECT_EQ(BaseBegin(m1), base1);
  EXPECT_EQ(BaseSize(m1), size1);
  // Write to the second region.
  memset(base1, 43, page_size);
  // Check the contents of the two regions.
  for (size_t i = 0; i < page_size; ++i) {
    EXPECT_EQ(base0[i], 42);
  }
  for (size_t i = 0; i < page_size; ++i) {
    EXPECT_EQ(base1[i], 43);
  }
  // Unmap the first region.
  delete m0;
  // Make sure the second region is still accessible after the first
  // region is unmapped.
  for (size_t i = 0; i < page_size; ++i) {
    EXPECT_EQ(base1[i], 43);
  }
  delete m1;
}

}  // namespace art