text: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "net/disk_cache/simple/simple_index_file.h"
  
  #include <memory>
  
  #include "base/files/file.h"
  #include "base/files/file_util.h"
  #include "base/files/scoped_temp_dir.h"
  #include "base/hash.h"
  #include "base/location.h"
  #include "base/logging.h"
  #include "base/pickle.h"
  #include "base/run_loop.h"
  #include "base/single_thread_task_runner.h"
  #include "base/threading/thread.h"
  #include "base/threading/thread_task_runner_handle.h"
  #include "base/time/time.h"
  #include "net/base/cache_type.h"
  #include "net/base/test_completion_callback.h"
  #include "net/disk_cache/backend_cleanup_tracker.h"
  #include "net/disk_cache/disk_cache_test_util.h"
  #include "net/disk_cache/simple/simple_backend_impl.h"
  #include "net/disk_cache/simple/simple_backend_version.h"
  #include "net/disk_cache/simple/simple_entry_format.h"
  #include "net/disk_cache/simple/simple_index.h"
  #include "net/disk_cache/simple/simple_util.h"
  #include "net/disk_cache/simple/simple_version_upgrade.h"
  #include "net/test/gtest_util.h"
  #include "net/test/test_with_scoped_task_environment.h"
  #include "testing/gmock/include/gmock/gmock.h"
  #include "testing/gtest/include/gtest/gtest.h"
  
  using net::test::IsOk;
  
  using base::Time;
  using disk_cache::SimpleIndexFile;
  using disk_cache::SimpleIndex;
  
  namespace disk_cache {
  
  // The Simple Cache backend requires a few guarantees from the filesystem like
  // atomic renaming of recently open files. Those guarantees are not provided in
  // general on Windows.
  #if defined(OS_POSIX)
  
  namespace {
  
  uint32_t RoundSize(uint32_t in) {
    return (in + 0xFFu) & 0xFFFFFF00u;
  }
  
  }  // namespace
  
  TEST(IndexMetadataTest, Basics) {
    SimpleIndexFile::IndexMetadata index_metadata;
  
    EXPECT_EQ(disk_cache::kSimpleIndexMagicNumber, index_metadata.magic_number_);
    EXPECT_EQ(disk_cache::kSimpleVersion, index_metadata.version_);
    EXPECT_EQ(0U, index_metadata.entry_count());
    EXPECT_EQ(0U, index_metadata.cache_size_);
  
    // Without setting a |reason_|, the index metadata isn't valid.
    index_metadata.reason_ = SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN;
  
    EXPECT_TRUE(index_metadata.CheckIndexMetadata());
  }
  
  TEST(IndexMetadataTest, Serialize) {
    SimpleIndexFile::IndexMetadata index_metadata(
        SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN, 123, 456);
    base::Pickle pickle;
    index_metadata.Serialize(&pickle);
    base::PickleIterator it(pickle);
    SimpleIndexFile::IndexMetadata new_index_metadata;
    new_index_metadata.Deserialize(&it);
  
    EXPECT_EQ(new_index_metadata.magic_number_, index_metadata.magic_number_);
    EXPECT_EQ(new_index_metadata.version_, index_metadata.version_);
    EXPECT_EQ(new_index_metadata.reason_, index_metadata.reason_);
    EXPECT_EQ(new_index_metadata.entry_count(), index_metadata.entry_count());
    EXPECT_EQ(new_index_metadata.cache_size_, index_metadata.cache_size_);
  
    EXPECT_TRUE(new_index_metadata.CheckIndexMetadata());
  }
  
  // This derived index metadata class allows us to serialize the older V6 format
  // of the index metadata, thus allowing us to test deserializing the old format.
  class V6IndexMetadataForTest : public SimpleIndexFile::IndexMetadata {
   public:
    // Do not default to |SimpleIndex::INDEX_WRITE_REASON_MAX|, because we want to
    // ensure we don't serialize that value and then deserialize it and have a
    // false positive result.
    V6IndexMetadataForTest(uint64_t entry_count, uint64_t cache_size)
        : SimpleIndexFile::IndexMetadata(SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN,
                                         entry_count,
                                         cache_size) {
      version_ = 6;
    }
  
    // Copied and pasted from the V6 implementation of
    // |SimpleIndexFile::IndexMetadata()| (removing DCHECKs).
    void Serialize(base::Pickle* pickle) const override {
      pickle->WriteUInt64(magic_number_);
      pickle->WriteUInt32(version_);
      pickle->WriteUInt64(entry_count_);
      pickle->WriteUInt64(cache_size_);
    }
  };
  
  TEST(IndexMetadataTest, ReadV6Format) {
    V6IndexMetadataForTest v6_index_metadata(123, 456);
    EXPECT_EQ(6U, v6_index_metadata.version_);
    base::Pickle pickle;
    v6_index_metadata.Serialize(&pickle);
    base::PickleIterator it(pickle);
    SimpleIndexFile::IndexMetadata new_index_metadata;
    new_index_metadata.Deserialize(&it);
  
    EXPECT_EQ(new_index_metadata.magic_number_, v6_index_metadata.magic_number_);
    EXPECT_EQ(new_index_metadata.version_, v6_index_metadata.version_);
  
    EXPECT_EQ(new_index_metadata.reason_, SimpleIndex::INDEX_WRITE_REASON_MAX);
    EXPECT_EQ(new_index_metadata.entry_count(), v6_index_metadata.entry_count());
    EXPECT_EQ(new_index_metadata.cache_size_, v6_index_metadata.cache_size_);
  
    EXPECT_TRUE(new_index_metadata.CheckIndexMetadata());
  }
  
  // This derived index metadata class allows us to serialize the older V7 format
  // of the index metadata, thus allowing us to test deserializing the old format.
  class V7IndexMetadataForTest : public SimpleIndexFile::IndexMetadata {
   public:
    V7IndexMetadataForTest(uint64_t entry_count, uint64_t cache_size)
        : SimpleIndexFile::IndexMetadata(SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN,
                                         entry_count,
                                         cache_size) {
      version_ = 7;
    }
  };
  
  // This friend derived class is able to reexport its ancestors private methods
  // as public, for use in tests.
  class WrappedSimpleIndexFile : public SimpleIndexFile {
   public:
    using SimpleIndexFile::Deserialize;
    using SimpleIndexFile::LegacyIsIndexFileStale;
    using SimpleIndexFile::Serialize;
    using SimpleIndexFile::SerializeFinalData;
  
    explicit WrappedSimpleIndexFile(const base::FilePath& index_file_directory)
        : SimpleIndexFile(base::ThreadTaskRunnerHandle::Get(),
                          base::ThreadTaskRunnerHandle::Get(),
                          net::DISK_CACHE,
                          index_file_directory) {}
    ~WrappedSimpleIndexFile() override = default;
  
    const base::FilePath& GetIndexFilePath() const {
      return index_file_;
    }
  
    const base::FilePath& GetTempIndexFilePath() const {
      return temp_index_file_;
    }
  
    bool CreateIndexFileDirectory() const {
      return base::CreateDirectory(index_file_.DirName());
    }
  };
  
  class SimpleIndexFileTest : public net::TestWithScopedTaskEnvironment {
   public:
    bool CompareTwoEntryMetadata(const EntryMetadata& a, const EntryMetadata& b) {
      return a.last_used_time_seconds_since_epoch_ ==
                 b.last_used_time_seconds_since_epoch_ &&
             a.entry_size_256b_chunks_ == b.entry_size_256b_chunks_ &&
             a.in_memory_data_ == b.in_memory_data_;
    }
  };
  
  TEST_F(SimpleIndexFileTest, Serialize) {
    SimpleIndex::EntrySet entries;
    static const uint64_t kHashes[] = {11, 22, 33};
    static const size_t kNumHashes = arraysize(kHashes);
    EntryMetadata metadata_entries[kNumHashes];
  
    SimpleIndexFile::IndexMetadata index_metadata(
        SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN,
        static_cast<uint64_t>(kNumHashes), 456);
    for (size_t i = 0; i < kNumHashes; ++i) {
      uint64_t hash = kHashes[i];
      // TODO(eroman): Should restructure the test so no casting here (and same
      //               elsewhere where a hash is cast to an entry size).
      metadata_entries[i] = EntryMetadata(Time(), static_cast<uint32_t>(hash));
      metadata_entries[i].SetInMemoryData(static_cast<uint8_t>(i));
      SimpleIndex::InsertInEntrySet(hash, metadata_entries[i], &entries);
    }
  
    std::unique_ptr<base::Pickle> pickle =
        WrappedSimpleIndexFile::Serialize(index_metadata, entries);
    EXPECT_TRUE(pickle.get() != NULL);
    base::Time now = base::Time::Now();
    WrappedSimpleIndexFile::SerializeFinalData(now, pickle.get());
    base::Time when_index_last_saw_cache;
    SimpleIndexLoadResult deserialize_result;
    WrappedSimpleIndexFile::Deserialize(static_cast<const char*>(pickle->data()),
                                        pickle->size(),
                                        &when_index_last_saw_cache,
                                        &deserialize_result);
    EXPECT_TRUE(deserialize_result.did_load);
    EXPECT_EQ(now, when_index_last_saw_cache);
    const SimpleIndex::EntrySet& new_entries = deserialize_result.entries;
    EXPECT_EQ(entries.size(), new_entries.size());
  
    for (size_t i = 0; i < kNumHashes; ++i) {
      SimpleIndex::EntrySet::const_iterator it = new_entries.find(kHashes[i]);
      EXPECT_TRUE(new_entries.end() != it);
      EXPECT_TRUE(CompareTwoEntryMetadata(it->second, metadata_entries[i]));
    }
  }
  
  TEST_F(SimpleIndexFileTest, ReadV7Format) {
    static const uint64_t kHashes[] = {11, 22, 33};
    static const uint32_t kSizes[] = {394, 594, 495940};
    static_assert(arraysize(kHashes) == arraysize(kSizes),
                  "Need same number of hashes and sizes");
    static const size_t kNumHashes = arraysize(kHashes);
  
    V7IndexMetadataForTest v7_metadata(kNumHashes, 100 * 1024 * 1024);
  
    // We don't have a convenient way of serializing the actual entries in the
    // V7 format, but we can cheat a bit by using the implementation details: if
    // we set the 8 lower bits of size as the memory data, and upper bits
    // as the size, the new serialization will produce what we want.
    SimpleIndex::EntrySet entries;
    for (size_t i = 0; i < kNumHashes; ++i) {
      EntryMetadata entry(Time(), kSizes[i] & 0xFFFFFF00u);
      entry.SetInMemoryData(static_cast<uint8_t>(kSizes[i] & 0xFFu));
      SimpleIndex::InsertInEntrySet(kHashes[i], entry, &entries);
    }
    std::unique_ptr<base::Pickle> pickle =
        WrappedSimpleIndexFile::Serialize(v7_metadata, entries);
    ASSERT_TRUE(pickle.get() != NULL);
    base::Time now = base::Time::Now();
    WrappedSimpleIndexFile::SerializeFinalData(now, pickle.get());
  
    // Now read it back. We should get the sizes rounded, and 0 for mem entries.
    base::Time when_index_last_saw_cache;
    SimpleIndexLoadResult deserialize_result;
    WrappedSimpleIndexFile::Deserialize(
        static_cast<const char*>(pickle->data()), pickle->size(),
        &when_index_last_saw_cache, &deserialize_result);
    EXPECT_TRUE(deserialize_result.did_load);
    EXPECT_EQ(now, when_index_last_saw_cache);
    const SimpleIndex::EntrySet& new_entries = deserialize_result.entries;
    ASSERT_EQ(entries.size(), new_entries.size());
    for (size_t i = 0; i < kNumHashes; ++i) {
      SimpleIndex::EntrySet::const_iterator it = new_entries.find(kHashes[i]);
      ASSERT_TRUE(new_entries.end() != it);
      EXPECT_EQ(RoundSize(kSizes[i]), it->second.GetEntrySize());
      EXPECT_EQ(0u, it->second.GetInMemoryData());
    }
  }
  
  TEST_F(SimpleIndexFileTest, LegacyIsIndexFileStale) {
    base::ScopedTempDir cache_dir;
    ASSERT_TRUE(cache_dir.CreateUniqueTempDir());
    base::Time cache_mtime;
    const base::FilePath cache_path = cache_dir.GetPath();
  
    ASSERT_TRUE(simple_util::GetMTime(cache_path, &cache_mtime));
    WrappedSimpleIndexFile simple_index_file(cache_path);
    ASSERT_TRUE(simple_index_file.CreateIndexFileDirectory());
    const base::FilePath& index_path = simple_index_file.GetIndexFilePath();
    EXPECT_TRUE(
        WrappedSimpleIndexFile::LegacyIsIndexFileStale(cache_mtime, index_path));
    const std::string kDummyData = "nothing to be seen here";
    EXPECT_EQ(static_cast<int>(kDummyData.size()),
              base::WriteFile(index_path,
                              kDummyData.data(), kDummyData.size()));
    ASSERT_TRUE(simple_util::GetMTime(cache_path, &cache_mtime));
    EXPECT_FALSE(
        WrappedSimpleIndexFile::LegacyIsIndexFileStale(cache_mtime, index_path));
  
    const base::Time past_time = base::Time::Now() -
        base::TimeDelta::FromSeconds(10);
    EXPECT_TRUE(base::TouchFile(index_path, past_time, past_time));
    EXPECT_TRUE(base::TouchFile(cache_path, past_time, past_time));
    ASSERT_TRUE(simple_util::GetMTime(cache_path, &cache_mtime));
    EXPECT_FALSE(
        WrappedSimpleIndexFile::LegacyIsIndexFileStale(cache_mtime, index_path));
    const base::Time even_older = past_time - base::TimeDelta::FromSeconds(10);
    EXPECT_TRUE(base::TouchFile(index_path, even_older, even_older));
    EXPECT_TRUE(
        WrappedSimpleIndexFile::LegacyIsIndexFileStale(cache_mtime, index_path));
  }
  
  TEST_F(SimpleIndexFileTest, WriteThenLoadIndex) {
    base::ScopedTempDir cache_dir;
    ASSERT_TRUE(cache_dir.CreateUniqueTempDir());
  
    SimpleIndex::EntrySet entries;
    static const uint64_t kHashes[] = {11, 22, 33};
    static const size_t kNumHashes = arraysize(kHashes);
    EntryMetadata metadata_entries[kNumHashes];
    for (size_t i = 0; i < kNumHashes; ++i) {
      uint64_t hash = kHashes[i];
      metadata_entries[i] = EntryMetadata(Time(), static_cast<uint32_t>(hash));
      SimpleIndex::InsertInEntrySet(hash, metadata_entries[i], &entries);
    }
  
    const uint64_t kCacheSize = 456U;
    net::TestClosure closure;
    {
      WrappedSimpleIndexFile simple_index_file(cache_dir.GetPath());
      simple_index_file.WriteToDisk(SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN,
                                    entries, kCacheSize, base::TimeTicks(), false,
                                    closure.closure());
      closure.WaitForResult();
      EXPECT_TRUE(base::PathExists(simple_index_file.GetIndexFilePath()));
    }
  
    WrappedSimpleIndexFile simple_index_file(cache_dir.GetPath());
    base::Time fake_cache_mtime;
    ASSERT_TRUE(simple_util::GetMTime(cache_dir.GetPath(), &fake_cache_mtime));
    SimpleIndexLoadResult load_index_result;
    simple_index_file.LoadIndexEntries(fake_cache_mtime, closure.closure(),
                                       &load_index_result);
    closure.WaitForResult();
  
    EXPECT_TRUE(base::PathExists(simple_index_file.GetIndexFilePath()));
    EXPECT_TRUE(load_index_result.did_load);
    EXPECT_FALSE(load_index_result.flush_required);
  
    EXPECT_EQ(kNumHashes, load_index_result.entries.size());
    for (size_t i = 0; i < kNumHashes; ++i)
      EXPECT_EQ(1U, load_index_result.entries.count(kHashes[i]));
  }
  
  TEST_F(SimpleIndexFileTest, LoadCorruptIndex) {
    base::ScopedTempDir cache_dir;
    ASSERT_TRUE(cache_dir.CreateUniqueTempDir());
  
    WrappedSimpleIndexFile simple_index_file(cache_dir.GetPath());
    ASSERT_TRUE(simple_index_file.CreateIndexFileDirectory());
    const base::FilePath& index_path = simple_index_file.GetIndexFilePath();
    const std::string kDummyData = "nothing to be seen here";
    EXPECT_EQ(static_cast<int>(kDummyData.size()),
              base::WriteFile(index_path, kDummyData.data(), kDummyData.size()));
    base::Time fake_cache_mtime;
    ASSERT_TRUE(simple_util::GetMTime(simple_index_file.GetIndexFilePath(),
                                      &fake_cache_mtime));
    EXPECT_FALSE(WrappedSimpleIndexFile::LegacyIsIndexFileStale(fake_cache_mtime,
                                                                index_path));
    SimpleIndexLoadResult load_index_result;
    net::TestClosure closure;
    simple_index_file.LoadIndexEntries(fake_cache_mtime, closure.closure(),
                                       &load_index_result);
    closure.WaitForResult();
  
    EXPECT_FALSE(base::PathExists(index_path));
    EXPECT_TRUE(load_index_result.did_load);
    EXPECT_TRUE(load_index_result.flush_required);
  }
  
  TEST_F(SimpleIndexFileTest, LoadCorruptIndex2) {
    // Variant where the index looks like a pickle, but not one with right
    // header size --- that used to hit a DCHECK on debug builds.
    base::ScopedTempDir cache_dir;
    ASSERT_TRUE(cache_dir.CreateUniqueTempDir());
  
    WrappedSimpleIndexFile simple_index_file(cache_dir.GetPath());
    ASSERT_TRUE(simple_index_file.CreateIndexFileDirectory());
    const base::FilePath& index_path = simple_index_file.GetIndexFilePath();
    base::Pickle bad_payload;
    bad_payload.WriteString("nothing to be seen here");
  
    EXPECT_EQ(
        static_cast<int>(bad_payload.size()),
        base::WriteFile(index_path, static_cast<const char*>(bad_payload.data()),
                        bad_payload.size()));
    base::Time fake_cache_mtime;
    ASSERT_TRUE(simple_util::GetMTime(simple_index_file.GetIndexFilePath(),
                                      &fake_cache_mtime));
    EXPECT_FALSE(WrappedSimpleIndexFile::LegacyIsIndexFileStale(fake_cache_mtime,
                                                                index_path));
    SimpleIndexLoadResult load_index_result;
    net::TestClosure closure;
    simple_index_file.LoadIndexEntries(fake_cache_mtime, closure.closure(),
                                       &load_index_result);
    closure.WaitForResult();
  
    EXPECT_FALSE(base::PathExists(index_path));
    EXPECT_TRUE(load_index_result.did_load);
    EXPECT_TRUE(load_index_result.flush_required);
  }
  
  // Tests that after an upgrade the backend has the index file put in place.
  TEST_F(SimpleIndexFileTest, SimpleCacheUpgrade) {
    base::ScopedTempDir cache_dir;
    ASSERT_TRUE(cache_dir.CreateUniqueTempDir());
    const base::FilePath cache_path = cache_dir.GetPath();
  
    // Write an old fake index file.
    base::File file(cache_path.AppendASCII("index"),
                    base::File::FLAG_CREATE | base::File::FLAG_WRITE);
    ASSERT_TRUE(file.IsValid());
    disk_cache::FakeIndexData file_contents;
    file_contents.initial_magic_number = disk_cache::kSimpleInitialMagicNumber;
    file_contents.version = 5;
    int bytes_written = file.Write(0, reinterpret_cast<char*>(&file_contents),
                                   sizeof(file_contents));
    ASSERT_EQ((int)sizeof(file_contents), bytes_written);
    file.Close();
  
    // Write the index file. The format is incorrect, but for transitioning from
    // v5 it does not matter.
    const std::string index_file_contents("incorrectly serialized data");
    const base::FilePath old_index_file =
        cache_path.AppendASCII("the-real-index");
    ASSERT_EQ(static_cast<int>(index_file_contents.size()),
              base::WriteFile(old_index_file, index_file_contents.data(),
                              index_file_contents.size()));
  
    // Upgrade the cache.
    ASSERT_TRUE(disk_cache::UpgradeSimpleCacheOnDisk(cache_path));
  
    // Create the backend and initiate index flush by destroying the backend.
    scoped_refptr<disk_cache::BackendCleanupTracker> cleanup_tracker =
        disk_cache::BackendCleanupTracker::TryCreate(cache_path,
                                                     base::OnceClosure());
    ASSERT_TRUE(cleanup_tracker != nullptr);
  
    net::TestClosure post_cleanup;
    cleanup_tracker->AddPostCleanupCallback(post_cleanup.closure());
  
    disk_cache::SimpleBackendImpl* simple_cache =
        new disk_cache::SimpleBackendImpl(
            cache_path, cleanup_tracker, /* file_tracker = */ nullptr, 0,
            net::DISK_CACHE, /* net_log = */ nullptr);
    net::TestCompletionCallback cb;
    int rv = simple_cache->Init(cb.callback());
    EXPECT_THAT(cb.GetResult(rv), IsOk());
    rv = simple_cache->index()->ExecuteWhenReady(cb.callback());
    EXPECT_THAT(cb.GetResult(rv), IsOk());
    delete simple_cache;
    cleanup_tracker = nullptr;
  
    // The backend flushes the index on destruction; it will run the post-cleanup
    // callback set on the cleanup_tracker once that finishes.
    post_cleanup.WaitForResult();
  
    // Verify that the index file exists.
    const base::FilePath& index_file_path =
        cache_path.AppendASCII("index-dir").AppendASCII("the-real-index");
    EXPECT_TRUE(base::PathExists(index_file_path));
  
    // Verify that the version of the index file is correct.
    std::string contents;
    EXPECT_TRUE(base::ReadFileToString(index_file_path, &contents));
    base::Time when_index_last_saw_cache;
    SimpleIndexLoadResult deserialize_result;
    WrappedSimpleIndexFile::Deserialize(contents.data(),
                                        contents.size(),
                                        &when_index_last_saw_cache,
                                        &deserialize_result);
    EXPECT_TRUE(deserialize_result.did_load);
  }
  
  TEST_F(SimpleIndexFileTest, OverwritesStaleTempFile) {
    base::ScopedTempDir cache_dir;
    ASSERT_TRUE(cache_dir.CreateUniqueTempDir());
    const base::FilePath cache_path = cache_dir.GetPath();
    WrappedSimpleIndexFile simple_index_file(cache_path);
    ASSERT_TRUE(simple_index_file.CreateIndexFileDirectory());
  
    // Create an temporary index file.
    const base::FilePath& temp_index_path =
        simple_index_file.GetTempIndexFilePath();
    const std::string kDummyData = "nothing to be seen here";
    EXPECT_EQ(
        static_cast<int>(kDummyData.size()),
        base::WriteFile(temp_index_path, kDummyData.data(), kDummyData.size()));
    ASSERT_TRUE(base::PathExists(simple_index_file.GetTempIndexFilePath()));
  
    // Write the index file.
    SimpleIndex::EntrySet entries;
    SimpleIndex::InsertInEntrySet(11, EntryMetadata(Time(), 11u), &entries);
    net::TestClosure closure;
    simple_index_file.WriteToDisk(SimpleIndex::INDEX_WRITE_REASON_SHUTDOWN,
                                  entries, 120U, base::TimeTicks(), false,
                                  closure.closure());
    closure.WaitForResult();
  
    // Check that the temporary file was deleted and the index file was created.
    EXPECT_FALSE(base::PathExists(simple_index_file.GetTempIndexFilePath()));
    EXPECT_TRUE(base::PathExists(simple_index_file.GetIndexFilePath()));
  }
  
  #endif  // defined(OS_POSIX)
  
  }  // namespace disk_cache
  