// 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 "components/download/public/common/download_path_reservation_tracker.h"

#include <stddef.h>
#include <stdint.h>

#include <array>
#include <memory>

#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/functional/bind.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/run_loop.h"
#include "base/strings/stringprintf.h"
#include "base/test/task_environment.h"
#include "base/test/test_file_util.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "components/download/public/common/mock_download_item.h"
#include "net/base/filename_util.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

#if BUILDFLAG(IS_ANDROID)
#include "components/download/internal/common/android/download_collection_bridge.h"
#endif  // BUILDFLAG(IS_ANDROID)

using testing::AnyNumber;
using testing::Return;
using testing::ReturnRef;
using testing::ReturnRefOfCopy;

namespace download {

namespace {

class DownloadPathReservationTrackerTest : public testing::Test {
 public:
  DownloadPathReservationTrackerTest();

  // testing::Test
  void SetUp() override;
  void TearDown() override;

  std::unique_ptr<MockDownloadItem> CreateDownloadItem(int32_t id);
  base::FilePath GetPathInDownloadsDirectory(
      const base::FilePath::CharType* suffix);
  bool IsPathInUse(const base::FilePath& path);
  void RunUntilIdle();
  void CallGetReservedPath(
      DownloadItem* download_item,
      const base::FilePath& target_path,
      bool create_directory,
      DownloadPathReservationTracker::FilenameConflictAction conflict_action,
      base::FilePath* return_path,
      PathValidationResult* return_result,
      const base::FilePath& containment_directory = base::FilePath());
  void CreateReservation(
      MockDownloadItem* item,
      const base::FilePath& path,
      DownloadPathReservationTracker::FilenameConflictAction conflict_action,
      PathValidationResult expected_result,
      const base::FilePath& expected_reserved_path);

  const base::FilePath& default_download_path() const {
    return default_download_path_;
  }
  void set_default_download_path(const base::FilePath& path) {
    default_download_path_ = path;
  }
  void set_fallback_directory(const base::FilePath& path) {
    fallback_directory_ = path;
  }
  // Creates a name of form 'a'*repeat + suffix
  base::FilePath GetLongNamePathInDownloadsDirectory(
      size_t repeat,
      const base::FilePath::CharType* suffix);

 protected:
  base::ScopedTempDir test_download_dir_;
  base::FilePath default_download_path_;
  base::FilePath fallback_directory_;
  base::test::TaskEnvironment task_environment_;

 private:
  void TestReservedPathCallback(base::FilePath* return_path,
                                PathValidationResult* return_result,
                                PathValidationResult result,
                                const base::FilePath& path);
};

DownloadPathReservationTrackerTest::DownloadPathReservationTrackerTest() =
    default;

void DownloadPathReservationTrackerTest::SetUp() {
  ASSERT_TRUE(test_download_dir_.CreateUniqueTempDir());
  set_default_download_path(test_download_dir_.GetPath());
#if BUILDFLAG(IS_ANDROID)
  // Initialize the global file name map for testing.
  if (DownloadCollectionBridge::ShouldPublishDownload(
          GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")))) {
    DownloadCollectionBridge::ResetExistingFileNamesForTesting();
  }
#endif
}

void DownloadPathReservationTrackerTest::TearDown() {
  RunUntilIdle();
}

std::unique_ptr<MockDownloadItem>
DownloadPathReservationTrackerTest::CreateDownloadItem(int32_t id) {
  auto item = std::make_unique<::testing::StrictMock<MockDownloadItem>>();
  EXPECT_CALL(*item, GetId()).WillRepeatedly(Return(id));
  EXPECT_CALL(*item, GetTargetFilePath())
      .WillRepeatedly(ReturnRefOfCopy(base::FilePath()));
  EXPECT_CALL(*item, GetTemporaryFilePath())
      .WillRepeatedly(Return(base::FilePath()));
  EXPECT_CALL(*item, GetState())
      .WillRepeatedly(Return(DownloadItem::IN_PROGRESS));
  EXPECT_CALL(*item, GetURL()).WillRepeatedly(ReturnRefOfCopy(GURL()));
  EXPECT_CALL(*item, IsTransient()).WillRepeatedly(Return(false));
  EXPECT_CALL(*item, GetForcedFilePath())
      .WillRepeatedly(ReturnRefOfCopy(base::FilePath()));
  EXPECT_CALL(*item, GetLastReason())
      .WillRepeatedly(Return(DOWNLOAD_INTERRUPT_REASON_NONE));
  EXPECT_CALL(*item, GetTargetDisposition())
      .WillRepeatedly(Return(DownloadItem::TARGET_DISPOSITION_OVERWRITE));

  static constexpr base::Time::Exploded kReferenceTime = {.year = 2019,
                                                          .month = 1,
                                                          .day_of_week = 3,
                                                          .day_of_month = 23,
                                                          .hour = 16,
                                                          .minute = 35,
                                                          .second = 30,
                                                          .millisecond = 20};
  base::Time test_time;
  EXPECT_TRUE(base::Time::FromLocalExploded(kReferenceTime, &test_time));

  EXPECT_CALL(*item, GetStartTime()).WillRepeatedly(Return(test_time));
  return item;
}

base::FilePath DownloadPathReservationTrackerTest::GetPathInDownloadsDirectory(
    const base::FilePath::CharType* suffix) {
  return default_download_path().Append(suffix).NormalizePathSeparators();
}

bool DownloadPathReservationTrackerTest::IsPathInUse(
    const base::FilePath& path) {
  RunUntilIdle();
  return DownloadPathReservationTracker::IsPathInUseForTesting(path);
}

void DownloadPathReservationTrackerTest::RunUntilIdle() {
  task_environment_.RunUntilIdle();
}

void DownloadPathReservationTrackerTest::CallGetReservedPath(
    DownloadItem* download_item,
    const base::FilePath& target_path,
    bool create_directory,
    DownloadPathReservationTracker::FilenameConflictAction conflict_action,
    base::FilePath* return_path,
    PathValidationResult* return_result,
    const base::FilePath& containment_directory) {
  // Weak pointer factory to prevent the callback from running after this
  // function has returned.
  base::WeakPtrFactory<DownloadPathReservationTrackerTest> weak_ptr_factory(
      this);
  DownloadPathReservationTracker::GetReservedPath(
      download_item, target_path, default_download_path(), fallback_directory_,
      create_directory, conflict_action,
      base::BindOnce(
          &DownloadPathReservationTrackerTest::TestReservedPathCallback,
          weak_ptr_factory.GetWeakPtr(), return_path, return_result),
      containment_directory);
  task_environment_.RunUntilIdle();
}

void DownloadPathReservationTrackerTest::TestReservedPathCallback(
    base::FilePath* return_path,
    PathValidationResult* return_result,
    PathValidationResult result,
    const base::FilePath& path) {
  *return_path = path;
  *return_result = result;
}

base::FilePath
DownloadPathReservationTrackerTest::GetLongNamePathInDownloadsDirectory(
    size_t repeat,
    const base::FilePath::CharType* suffix) {
  return GetPathInDownloadsDirectory(
      (base::FilePath::StringType(repeat, FILE_PATH_LITERAL('a')) + suffix)
          .c_str());
}

void SetDownloadItemState(MockDownloadItem* download_item,
                          DownloadItem::DownloadState state) {
  EXPECT_CALL(*download_item, GetState()).WillRepeatedly(Return(state));
  download_item->NotifyObserversDownloadUpdated();
}

void DownloadPathReservationTrackerTest::CreateReservation(
    MockDownloadItem* item,
    const base::FilePath& path,
    DownloadPathReservationTracker::FilenameConflictAction conflict_action,
    PathValidationResult expected_result,
    const base::FilePath& expected_reserved_path) {
  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::NAME_TOO_LONG;
  bool create_directory = false;
  CallGetReservedPath(item, path, create_directory, conflict_action,
                      &reserved_path, &result);
  if (result != PathValidationResult::PATH_NOT_WRITABLE)
    EXPECT_TRUE(IsPathInUse(path));
  EXPECT_EQ(expected_result, result);
  EXPECT_EQ(expected_reserved_path, reserved_path);
}

}  // namespace

// A basic reservation is acquired and committed.
TEST_F(DownloadPathReservationTrackerTest, BasicReservation) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  ASSERT_FALSE(IsPathInUse(path));
  CreateReservation(item.get(), path, DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, path);

  // Destroying the item should release the reservation.
  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
  EXPECT_FALSE(IsPathInUse(path));
}

// A download that is interrupted should lose its reservation.
TEST_F(DownloadPathReservationTrackerTest, InterruptedDownload) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  ASSERT_FALSE(IsPathInUse(path));
  CreateReservation(item.get(), path, DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, path);

  // Once the download is interrupted, the path should become available again.
  SetDownloadItemState(item.get(), DownloadItem::INTERRUPTED);
  RunUntilIdle();
  EXPECT_FALSE(IsPathInUse(path));
}

// A completed download should also lose its reservation.
TEST_F(DownloadPathReservationTrackerTest, CompleteDownload) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  ASSERT_FALSE(IsPathInUse(path));

  CreateReservation(item.get(), path, DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, path);

  // Once the download completes, the path should become available again. For a
  // real download, at this point only the path reservation will be released.
  // The path wouldn't be available since it is occupied on disk by the
  // completed download.
  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  RunUntilIdle();
  EXPECT_FALSE(IsPathInUse(path));
}

// If there are files on the file system, a unique reservation should uniquify
// around it.
TEST_F(DownloadPathReservationTrackerTest, ConflictingFiles) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);

  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  base::FilePath path1(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo (1).txt")));
  bool use_download_collection = false;
#if BUILDFLAG(IS_ANDROID)
  if (DownloadCollectionBridge::ShouldPublishDownload(path)) {
    use_download_collection = true;
    DownloadCollectionBridge::AddExistingFileNameForTesting(path.BaseName());
  }
#endif  // BUILDFLAG(IS_ANDROID)
  if (!use_download_collection) {
    // Create a file at |path|, and a .crdownload file at |path1|.
    ASSERT_TRUE(base::WriteFile(path, ""));
    ASSERT_TRUE(base::WriteFile(
        base::FilePath(path1.value() + FILE_PATH_LITERAL(".crdownload")), ""));
  }

  ASSERT_TRUE(IsPathInUse(path));

  CreateReservation(item.get(), path, DownloadPathReservationTracker::UNIQUIFY,
                    PathValidationResult::SUCCESS_RESOLVED_CONFLICT, path1);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
  EXPECT_TRUE(IsPathInUse(path));
  EXPECT_FALSE(IsPathInUse(path1));
}

// As above, but checks for existing files that differ only by case.
TEST_F(DownloadPathReservationTrackerTest, CaseConflictingFiles) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);

  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  base::FilePath target_path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("FOO.txt")));
  base::FilePath path1(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("FOO (1).txt")));
  bool use_download_collection = false;
#if BUILDFLAG(IS_ANDROID)
  if (DownloadCollectionBridge::ShouldPublishDownload(path)) {
    use_download_collection = true;
    DownloadCollectionBridge::AddExistingFileNameForTesting(path.BaseName());
  }
#endif  // BUILDFLAG(IS_ANDROID)
  if (!use_download_collection) {
    // Create a file at |path|, and a .crdownload file at |path1|.
    ASSERT_TRUE(base::WriteFile(path, ""));
    ASSERT_TRUE(base::WriteFile(
        base::FilePath(path1.value() + FILE_PATH_LITERAL(".crdownload")), ""));
  }

  ASSERT_TRUE(IsPathInUse(path));

  // Whether this counts as a conflict depends on whether the filesystem is
  // actually case-sensitive.
  CreateReservation(
      item.get(), target_path, DownloadPathReservationTracker::UNIQUIFY,
      IsPathInUse(target_path) ? PathValidationResult::SUCCESS_RESOLVED_CONFLICT
                               : PathValidationResult::SUCCESS,
      IsPathInUse(target_path) ? path1 : target_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
  EXPECT_TRUE(IsPathInUse(path));
  EXPECT_FALSE(IsPathInUse(path1));
}

// If there are conflicting files on the file system, an overwriting reservation
// should succeed without altering the target path.
TEST_F(DownloadPathReservationTrackerTest, ConflictingFiles_Overwrite) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  bool use_download_collection = false;
#if BUILDFLAG(IS_ANDROID)
  if (DownloadCollectionBridge::ShouldPublishDownload(path)) {
    use_download_collection = true;
    DownloadCollectionBridge::AddExistingFileNameForTesting(path.BaseName());
  }
#endif  // BUILDFLAG(IS_ANDROID)
  if (!use_download_collection) {
    // Create a file at |path|.
    ASSERT_TRUE(base::WriteFile(path, ""));
  }
  ASSERT_TRUE(IsPathInUse(path));

  CreateReservation(item.get(), path, DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
}

// As above, but checks for existing files that differ only by case. On a
// case-sensitive filesystem this is redundant, since the files won't actually
// conflict, but it's easier to run the test everywhere than to check the
// filesystem type.
TEST_F(DownloadPathReservationTrackerTest, CaseConflictingFiles_Overwrite) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  base::FilePath target_path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("FOO.txt")));
  bool use_download_collection = false;
#if BUILDFLAG(IS_ANDROID)
  if (DownloadCollectionBridge::ShouldPublishDownload(path)) {
    use_download_collection = true;
    DownloadCollectionBridge::AddExistingFileNameForTesting(path.BaseName());
  }
#endif  // BUILDFLAG(IS_ANDROID)
  if (!use_download_collection) {
    // Create a file at |path|.
    ASSERT_TRUE(base::WriteFile(path, ""));
  }
  ASSERT_TRUE(IsPathInUse(path));

  CreateReservation(item.get(), target_path,
                    DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, target_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
}

// If the source is a file:// URL that is in the download directory, then Chrome
// could download the file onto itself. Test that this is flagged by DPRT.
TEST_F(DownloadPathReservationTrackerTest, ConflictWithSource) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  bool use_download_collection = false;
#if BUILDFLAG(IS_ANDROID)
  if (DownloadCollectionBridge::ShouldPublishDownload(path)) {
    use_download_collection = true;
    DownloadCollectionBridge::AddExistingFileNameForTesting(path.BaseName());
  }
#endif  // BUILDFLAG(IS_ANDROID)
  if (!use_download_collection) {
    ASSERT_TRUE(base::WriteFile(path, ""));
  }
  ASSERT_TRUE(IsPathInUse(path));
  EXPECT_CALL(*item, GetURL())
      .WillRepeatedly(ReturnRefOfCopy(net::FilePathToFileURL(path)));

  CreateReservation(item.get(), path, DownloadPathReservationTracker::UNIQUIFY,
                    PathValidationResult::SAME_AS_SOURCE, path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
}

// As above, but check for a file:// URL that differs only by case. This should
// be flagged on all file systems, even case-sensitive ones, for safety.
TEST_F(DownloadPathReservationTrackerTest, CaseConflictWithSource) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  base::FilePath target_path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("FOO.txt")));
  bool use_download_collection = false;
#if BUILDFLAG(IS_ANDROID)
  if (DownloadCollectionBridge::ShouldPublishDownload(path)) {
    use_download_collection = true;
    DownloadCollectionBridge::AddExistingFileNameForTesting(path.BaseName());
  }
#endif  // BUILDFLAG(IS_ANDROID)
  if (!use_download_collection) {
    ASSERT_TRUE(base::WriteFile(path, ""));
  }
  ASSERT_TRUE(IsPathInUse(path));
  EXPECT_CALL(*item, GetURL())
      .WillRepeatedly(ReturnRefOfCopy(net::FilePathToFileURL(path)));

  CreateReservation(item.get(), target_path,
                    DownloadPathReservationTracker::UNIQUIFY,
                    PathValidationResult::SAME_AS_SOURCE, target_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
}

// Multiple reservations for the same path should uniquify around each other.
TEST_F(DownloadPathReservationTrackerTest, ConflictingReservations) {
  std::unique_ptr<MockDownloadItem> item1 = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  base::FilePath uniquified_path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo (1).txt")));
  ASSERT_FALSE(IsPathInUse(path));
  ASSERT_FALSE(IsPathInUse(uniquified_path));

  CreateReservation(item1.get(), path, DownloadPathReservationTracker::UNIQUIFY,
                    PathValidationResult::SUCCESS, path);

  {
    // Requesting a reservation for the same path with uniquification results in
    // a uniquified path.
    std::unique_ptr<MockDownloadItem> item2 = CreateDownloadItem(2);
    CreateReservation(
        item2.get(), path, DownloadPathReservationTracker::UNIQUIFY,
        PathValidationResult::SUCCESS_RESOLVED_CONFLICT, uniquified_path);
    SetDownloadItemState(item2.get(), DownloadItem::COMPLETE);
  }
  RunUntilIdle();
  EXPECT_TRUE(IsPathInUse(path));
  EXPECT_FALSE(IsPathInUse(uniquified_path));

  {
    // Since the previous download item was removed, requesting a reservation
    // for the same path should result in the same uniquified path.
    std::unique_ptr<MockDownloadItem> item2 = CreateDownloadItem(2);
    CreateReservation(
        item2.get(), path, DownloadPathReservationTracker::UNIQUIFY,
        PathValidationResult::SUCCESS_RESOLVED_CONFLICT, uniquified_path);
    SetDownloadItemState(item2.get(), DownloadItem::COMPLETE);
  }
  RunUntilIdle();

  // Now acquire an overwriting reservation. It should end up with a CONFLICT
  // result.
  std::unique_ptr<MockDownloadItem> item3 = CreateDownloadItem(2);
  CreateReservation(item3.get(), path,
                    DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::CONFLICT, path);

  SetDownloadItemState(item1.get(), DownloadItem::COMPLETE);
  SetDownloadItemState(item3.get(), DownloadItem::COMPLETE);
}

// An OVERWRITE reservation with the same path as an active reservation should
// return a CONFLICT result.
TEST_F(DownloadPathReservationTrackerTest, ConflictingReservation_Prevented) {
  std::unique_ptr<MockDownloadItem> item1 = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  ASSERT_FALSE(IsPathInUse(path));

  CreateReservation(item1.get(), path,
                    DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, path);

  std::unique_ptr<MockDownloadItem> item2 = CreateDownloadItem(2);
  CreateReservation(item2.get(), path,
                    DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::CONFLICT, path);

  SetDownloadItemState(item1.get(), DownloadItem::COMPLETE);
  SetDownloadItemState(item2.get(), DownloadItem::COMPLETE);
}

// Two active downloads shouldn't be able to reserve paths that only differ by
// case.
TEST_F(DownloadPathReservationTrackerTest, ConflictingCaseReservations) {
  std::unique_ptr<MockDownloadItem> item1 = CreateDownloadItem(1);
  std::unique_ptr<MockDownloadItem> item2 = CreateDownloadItem(2);

  base::FilePath path_foo =
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt"));
  base::FilePath path_Foo =
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("Foo.txt"));

  CreateReservation(item1.get(), path_foo,
                    DownloadPathReservationTracker::UNIQUIFY,
                    PathValidationResult::SUCCESS, path_foo);

  // Foo should also be in use at this point.
  EXPECT_TRUE(IsPathInUse(path_Foo));

  CreateReservation(
      item2.get(), path_Foo, DownloadPathReservationTracker::UNIQUIFY,
      PathValidationResult::SUCCESS_RESOLVED_CONFLICT,
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("Foo (1).txt")));

  SetDownloadItemState(item1.get(), DownloadItem::COMPLETE);
  SetDownloadItemState(item2.get(), DownloadItem::COMPLETE);
}

// If a unique path cannot be determined after trying kMaxUniqueFiles
// uniquifiers, then the callback should notified that verification failed, and
// the returned path should be set to the original requested path.
TEST_F(DownloadPathReservationTrackerTest, UnresolvedConflicts) {
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  // Make room for the path with no uniquifier, the |kMaxUniqueFiles|
  // numerically uniquified paths, and then one more for the timestamp
  // uniquified path.
  std::array<std::unique_ptr<MockDownloadItem>,
             DownloadPathReservationTracker::kMaxUniqueFiles + 2>
      items;

  // Create |kMaxUniqueFiles + 2| reservations for |path|. The first reservation
  // will have no uniquifier. Then |kMaxUniqueFiles| paths have numeric
  // uniquifiers. Then one more will have a timestamp uniquifier.
  for (int i = 0; i <= DownloadPathReservationTracker::kMaxUniqueFiles + 1;
       i++) {
    SCOPED_TRACE(testing::Message() << "i = " << i);
    base::FilePath expected_path;
    PathValidationResult expected_result =
        PathValidationResult::SUCCESS_RESOLVED_CONFLICT;
    if (i == 0) {
      expected_path = path;
      expected_result = PathValidationResult::SUCCESS;
    } else if (i > 0 && i <= DownloadPathReservationTracker::kMaxUniqueFiles) {
      expected_path =
          path.InsertBeforeExtensionASCII(base::StringPrintf(" (%d)", i));
    } else {
      expected_path =
          path.InsertBeforeExtensionASCII(" - 2019-01-23T163530.020");
    }
    items[i] = CreateDownloadItem(i);
    EXPECT_FALSE(IsPathInUse(expected_path));

    CreateReservation(items[i].get(), path,
                      DownloadPathReservationTracker::UNIQUIFY, expected_result,
                      expected_path);
  }
  // The next reservation for |path| will fail to be unique.
  std::unique_ptr<MockDownloadItem> download_item =
      CreateDownloadItem(DownloadPathReservationTracker::kMaxUniqueFiles + 2);
  CreateReservation(download_item.get(), path,
                    DownloadPathReservationTracker::UNIQUIFY,
                    PathValidationResult::CONFLICT, path);

  SetDownloadItemState(download_item.get(), DownloadItem::COMPLETE);
  for (auto& item : items)
    SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

#if BUILDFLAG(IS_FUCHSIA)
// TODO(crbug.com/40221275): Re-enable when UnwriteableDirectory works on
// Fuchsia.
#define MAYBE_UnwriteableDirectory DISABLED_UnwriteableDirectory
#else
#define MAYBE_UnwriteableDirectory UnwriteableDirectory
#endif
// If the target directory is unwriteable, then callback should be notified that
// verification failed.
TEST_F(DownloadPathReservationTrackerTest, MAYBE_UnwriteableDirectory) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
#if BUILDFLAG(IS_ANDROID)
  // This test is only valid works if download collection is not used.
  if (DownloadCollectionBridge::ShouldPublishDownload(path))
    return;
#endif  // BUILDFLAG(IS_ANDROID)
  base::FilePath dir(path.DirName());
  ASSERT_FALSE(IsPathInUse(path));

  {
    // Scope for FilePermissionRestorer
    base::FilePermissionRestorer restorer(dir);
    EXPECT_TRUE(base::MakeFileUnwritable(dir));
    base::FilePath fallback_dir(FILE_PATH_LITERAL("/tmp/download"));
    set_fallback_directory(fallback_dir);
    CreateReservation(item.get(), path,
                      DownloadPathReservationTracker::OVERWRITE,
                      PathValidationResult::PATH_NOT_WRITABLE,
                      fallback_dir.Append(path.BaseName()));

    // Change the default download dir to something else.
    base::FilePath default_download_path =
        GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo/foo.txt"));
    set_default_download_path(default_download_path);

    CreateReservation(item.get(), path,
                      DownloadPathReservationTracker::OVERWRITE,
                      PathValidationResult::PATH_NOT_WRITABLE,
                      default_download_path.Append(path.BaseName()));
  }

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

// If the default download directory doesn't exist, then it should be
// created. But only if we are actually going to create the download path there.
TEST_F(DownloadPathReservationTrackerTest, CreateDefaultDownloadPath) {
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo/foo.txt")));
#if BUILDFLAG(IS_ANDROID)
  // This test is only valid works if download collection is not used.
  if (DownloadCollectionBridge::ShouldPublishDownload(path))
    return;
#endif  // BUILDFLAG(IS_ANDROID)
  base::FilePath dir(path.DirName());
  ASSERT_FALSE(base::DirectoryExists(dir));

  {
    std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
    CreateReservation(
        item.get(), path, DownloadPathReservationTracker::OVERWRITE,
        PathValidationResult::PATH_NOT_WRITABLE,
        GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
    SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  }
  ASSERT_FALSE(IsPathInUse(path));
  {
    std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
    set_default_download_path(dir);
    CreateReservation(item.get(), path,
                      DownloadPathReservationTracker::OVERWRITE,
                      PathValidationResult::SUCCESS, path);
    EXPECT_TRUE(base::DirectoryExists(dir));
    SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  }
}

// If the target path of the download item changes, the reservation should be
// updated to match.
TEST_F(DownloadPathReservationTrackerTest, UpdatesToTargetPath) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("foo.txt")));
  ASSERT_FALSE(IsPathInUse(path));

  CreateReservation(item.get(), path, DownloadPathReservationTracker::OVERWRITE,
                    PathValidationResult::SUCCESS, path);

  // The target path is initially empty. If an OnDownloadUpdated() is issued in
  // this state, we shouldn't lose the reservation.
  ASSERT_EQ(base::FilePath::StringType(), item->GetTargetFilePath().value());
  item->NotifyObserversDownloadUpdated();
  RunUntilIdle();
  EXPECT_TRUE(IsPathInUse(path));

  // If the target path changes, we should update the reservation to match.
  base::FilePath new_target_path(
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("bar.txt")));
  ASSERT_FALSE(IsPathInUse(new_target_path));
  EXPECT_CALL(*item, GetTargetFilePath())
      .WillRepeatedly(ReturnRef(new_target_path));
  item->NotifyObserversDownloadUpdated();
  RunUntilIdle();
  EXPECT_FALSE(IsPathInUse(path));
  EXPECT_TRUE(IsPathInUse(new_target_path));

  // Destroying the item should release the reservation.
  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
  item.reset();
  RunUntilIdle();
  EXPECT_FALSE(IsPathInUse(new_target_path));
}

// Tests for long name truncation. On other platforms automatic truncation
// is not performed (yet).
#if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_CHROMEOS)

TEST_F(DownloadPathReservationTrackerTest, BasicTruncation) {
  int real_max_length =
      base::GetMaximumPathComponentLength(default_download_path());
  ASSERT_NE(-1, real_max_length);

#if BUILDFLAG(IS_WIN)
  const size_t max_length = real_max_length - strlen(":Zone.Identifier");
#else
  // TODO(kinaba): the current implementation leaves spaces for appending
  // ".crdownload". So take it into account. Should be removed in the future.
  const size_t max_length = real_max_length - 11;
#endif  // BUILDFLAG(IS_WIN)

  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(GetLongNamePathInDownloadsDirectory(
      max_length, FILE_PATH_LITERAL(".txt")));
  ASSERT_FALSE(IsPathInUse(path));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::NAME_TOO_LONG;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::OVERWRITE;
  bool create_directory = false;
  CallGetReservedPath(item.get(), path, create_directory, conflict_action,
                      &reserved_path, &result);
  EXPECT_TRUE(IsPathInUse(reserved_path));
  EXPECT_EQ(PathValidationResult::SUCCESS, result);
  // The file name length is truncated to max_length.
  EXPECT_EQ(max_length, reserved_path.BaseName().value().size());
  // But the extension is kept unchanged.
  EXPECT_EQ(path.Extension(), reserved_path.Extension());
  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

TEST_F(DownloadPathReservationTrackerTest, TruncationConflict) {
  int real_max_length =
      base::GetMaximumPathComponentLength(default_download_path());
  ASSERT_NE(-1, real_max_length);
#if BUILDFLAG(IS_WIN)
  const size_t max_length = real_max_length - strlen(":Zone.Identifier");
#else
  const size_t max_length = real_max_length - 11;
#endif  // BUILDFLAG(IS_WIN)

  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(GetLongNamePathInDownloadsDirectory(
      max_length, FILE_PATH_LITERAL(".txt")));
  base::FilePath path0(GetLongNamePathInDownloadsDirectory(
      max_length - 4, FILE_PATH_LITERAL(".txt")));
  base::FilePath path1(GetLongNamePathInDownloadsDirectory(
      max_length - 8, FILE_PATH_LITERAL(" (1).txt")));
  base::FilePath path2(GetLongNamePathInDownloadsDirectory(
      max_length - 8, FILE_PATH_LITERAL(" (2).txt")));
  ASSERT_FALSE(IsPathInUse(path));
  // "aaa...aaaaaaa.txt" (truncated path) and
  // "aaa...aaa (1).txt" (truncated and first uniquification try) exists.
  // "aaa...aaa (2).txt" should be used.
  ASSERT_TRUE(base::WriteFile(path0, ""));
  ASSERT_TRUE(base::WriteFile(path1, ""));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::NAME_TOO_LONG;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::UNIQUIFY;
  bool create_directory = false;
  CallGetReservedPath(item.get(), path, create_directory, conflict_action,
                      &reserved_path, &result);
  EXPECT_TRUE(IsPathInUse(reserved_path));
  EXPECT_EQ(PathValidationResult::SUCCESS_RESOLVED_CONFLICT, result);
  EXPECT_EQ(path2, reserved_path);
  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

TEST_F(DownloadPathReservationTrackerTest, TruncationFail) {
  int real_max_length =
      base::GetMaximumPathComponentLength(default_download_path());
  ASSERT_NE(-1, real_max_length);
#if BUILDFLAG(IS_WIN)
  const size_t max_length = real_max_length - strlen(":Zone.Identifier");
#else
  const size_t max_length = real_max_length - 11;
#endif  // BUILDFLAG(IS_WIN)

  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::FilePath path(GetPathInDownloadsDirectory(
      (FILE_PATH_LITERAL("a.") + base::FilePath::StringType(max_length, 'b'))
          .c_str()));
  ASSERT_FALSE(IsPathInUse(path));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::SUCCESS;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::OVERWRITE;
  bool create_directory = false;
  CallGetReservedPath(item.get(), path, create_directory, conflict_action,
                      &reserved_path, &result);
  // We cannot truncate a path with very long extension.
  EXPECT_EQ(PathValidationResult::NAME_TOO_LONG, result);
  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

#endif  // Platforms that support filename truncation.

#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
TEST_F(DownloadPathReservationTrackerTest, SymlinkTraversingPath) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  base::ScopedTempDir external_dir;
  ASSERT_TRUE(external_dir.CreateUniqueTempDir());

  base::FilePath symlink_path =
      GetPathInDownloadsDirectory(FILE_PATH_LITERAL("symlink_dir"));
  ASSERT_TRUE(base::CreateSymbolicLink(external_dir.GetPath(), symlink_path));

  base::FilePath target_path =
      symlink_path.Append(FILE_PATH_LITERAL("payload.txt"));
  ASSERT_FALSE(IsPathInUse(target_path));

  CreateReservation(
      item.get(), target_path, DownloadPathReservationTracker::OVERWRITE,
      PathValidationResult::PATH_NOT_WRITABLE,
      default_download_path().Append(FILE_PATH_LITERAL("payload.txt")));

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}
#endif

TEST_F(DownloadPathReservationTrackerTest,
       ConfirmedPathOutsideDownloadsResumption) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  EXPECT_CALL(*item, GetTargetDisposition())
      .WillRepeatedly(Return(DownloadItem::TARGET_DISPOSITION_PROMPT));

  base::ScopedTempDir external_dir;
  ASSERT_TRUE(external_dir.CreateUniqueTempDir());

  base::FilePath target_path =
      external_dir.GetPath().Append(FILE_PATH_LITERAL("payload.txt"));
  ASSERT_FALSE(IsPathInUse(target_path));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::SUCCESS;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::OVERWRITE;
  bool create_directory = false;
  CallGetReservedPath(item.get(), target_path, create_directory,
                      conflict_action, &reserved_path, &result);
  EXPECT_EQ(PathValidationResult::SUCCESS, result);
  EXPECT_EQ(target_path, reserved_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

TEST_F(DownloadPathReservationTrackerTest,
       ResumedPathOutsideDownloadsAfterRestart) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);
  // Simulate a restart where TargetDisposition defaults to OVERWRITE,
  // but the download is recognized as resumed due to a non-zero interrupt
  // reason.
  EXPECT_CALL(*item, GetTargetDisposition())
      .WillRepeatedly(Return(DownloadItem::TARGET_DISPOSITION_OVERWRITE));
  EXPECT_CALL(*item, GetLastReason())
      .WillRepeatedly(Return(download::DOWNLOAD_INTERRUPT_REASON_CRASH));

  base::ScopedTempDir external_dir;
  ASSERT_TRUE(external_dir.CreateUniqueTempDir());

  base::FilePath target_path =
      external_dir.GetPath().Append(FILE_PATH_LITERAL("payload.txt"));
  ASSERT_FALSE(IsPathInUse(target_path));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::SUCCESS;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::OVERWRITE;
  bool create_directory = false;
  CallGetReservedPath(item.get(), target_path, create_directory,
                      conflict_action, &reserved_path, &result);
  EXPECT_EQ(PathValidationResult::SUCCESS, result);
  EXPECT_EQ(target_path, reserved_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

TEST_F(DownloadPathReservationTrackerTest,
       PathOutsideDownloadsButInsideContainment) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);

  base::ScopedTempDir external_dir;
  ASSERT_TRUE(external_dir.CreateUniqueTempDir());

  base::FilePath target_path =
      external_dir.GetPath().Append(FILE_PATH_LITERAL("payload.txt"));
  ASSERT_FALSE(IsPathInUse(target_path));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::SUCCESS;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::OVERWRITE;
  bool create_directory = false;

  CallGetReservedPath(item.get(), target_path, create_directory,
                      conflict_action, &reserved_path, &result,
                      external_dir.GetPath());
  EXPECT_EQ(PathValidationResult::SUCCESS, result);
  EXPECT_EQ(target_path, reserved_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}

#if BUILDFLAG(IS_ANDROID)
TEST_F(DownloadPathReservationTrackerTest,
       AndroidPathOutsideDownloadsDirectory) {
  std::unique_ptr<MockDownloadItem> item = CreateDownloadItem(1);

  base::ScopedTempDir external_dir;
  ASSERT_TRUE(external_dir.CreateUniqueTempDir());

  base::FilePath target_path =
      external_dir.GetPath().Append(FILE_PATH_LITERAL("payload.txt"));
  ASSERT_FALSE(IsPathInUse(target_path));

  base::FilePath reserved_path;
  PathValidationResult result = PathValidationResult::SUCCESS;
  DownloadPathReservationTracker::FilenameConflictAction conflict_action =
      DownloadPathReservationTracker::OVERWRITE;
  bool create_directory = false;

  CallGetReservedPath(item.get(), target_path, create_directory,
                      conflict_action, &reserved_path, &result);
  EXPECT_EQ(PathValidationResult::SUCCESS, result);
  EXPECT_EQ(target_path, reserved_path);

  SetDownloadItemState(item.get(), DownloadItem::COMPLETE);
}
#endif

}  // namespace download