// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Cross platform methods for FilePathWatcher. See the various platform
// specific implementation files, too.

#include "content/browser/file_system_access/file_path_watcher/file_path_watcher.h"

#include <memory>
#include <utility>

#include "base/check.h"
#include "base/files/file_path.h"
#include "build/build_config.h"
#include "content/browser/file_system_access/features.h"

namespace content {

// static
size_t FilePathWatcher::quota_limit_override_for_testing_ = 0;

FilePathWatcher::ChangeInfo::ChangeInfo() = default;

FilePathWatcher::ChangeInfo::ChangeInfo(
    FilePathWatcher::FilePathType file_path_type,
    FilePathWatcher::ChangeType change_type,
    base::FilePath modified_path)
    : file_path_type(file_path_type),
      change_type(change_type),
      modified_path(modified_path) {}

FilePathWatcher::ChangeInfo::ChangeInfo(
    FilePathWatcher::FilePathType file_path_type,
    FilePathWatcher::ChangeType change_type,
    base::FilePath modified_path,
    std::optional<base::FilePath> moved_from_path)
    : file_path_type(file_path_type),
      change_type(change_type),
      modified_path(modified_path),
      moved_from_path(moved_from_path) {}

FilePathWatcher::ChangeInfo::~ChangeInfo() = default;

FilePathWatcher::ChangeInfo::ChangeInfo(const FilePathWatcher::ChangeInfo&) =
    default;
FilePathWatcher::ChangeInfo::ChangeInfo(FilePathWatcher::ChangeInfo&&) =
    default;
FilePathWatcher::ChangeInfo& FilePathWatcher::ChangeInfo::operator=(
    const FilePathWatcher::ChangeInfo&) = default;
FilePathWatcher::ChangeInfo& FilePathWatcher::ChangeInfo::operator=(
    FilePathWatcher::ChangeInfo&&) noexcept = default;

FilePathWatcher::~FilePathWatcher() {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  impl_->Cancel();
}

// static
bool FilePathWatcher::RecursiveWatchAvailable() {
#if BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN) || BUILDFLAG(IS_LINUX) || \
    BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_FUCHSIA) || BUILDFLAG(IS_AIX)
  return true;
#else
  // FSEvents isn't available on iOS.
  return false;
#endif
}

FilePathWatcher::PlatformDelegate::PlatformDelegate() = default;

FilePathWatcher::PlatformDelegate::~PlatformDelegate() {
  DCHECK(is_cancelled());
}

size_t FilePathWatcher::PlatformDelegate::current_usage() const {
  return 0;
}

bool FilePathWatcher::Watch(const base::FilePath& path,
                            Type type,
                            const Callback& callback) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  DCHECK(path.IsAbsolute());
  return impl_->Watch(path, type, callback);
}

bool FilePathWatcher::WatchWithOptions(const base::FilePath& path,
                                       const WatchOptions& options,
                                       const Callback& callback) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  DCHECK(path.IsAbsolute());
  return impl_->WatchWithOptions(path, options, callback);
}

std::optional<size_t> FilePathWatcher::WatchWithChangeInfo(
    const base::FilePath& path,
    const WatchOptions& options,
    const CallbackWithChangeInfo& callback,
    const UsageChangeCallback& usage_callback) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  DCHECK(path.IsAbsolute());
  if (impl_->WatchWithChangeInfo(path, options, callback, usage_callback)) {
    return impl_->current_usage();
  }
  return std::nullopt;
}

bool FilePathWatcher::PlatformDelegate::WatchWithOptions(
    const base::FilePath& path,
    const WatchOptions& options,
    const Callback& callback) {
  return Watch(path, options.type, callback);
}

bool FilePathWatcher::PlatformDelegate::WatchWithChangeInfo(
    const base::FilePath& path,
    const WatchOptions& options,
    const CallbackWithChangeInfo& callback,
    const UsageChangeCallback& usage_callback) {
  return Watch(path, options.type, base::BindRepeating(callback, ChangeInfo()));
}

FilePathWatcher::FilePathWatcher(std::unique_ptr<PlatformDelegate> delegate) {
  DETACH_FROM_SEQUENCE(sequence_checker_);
  impl_ = std::move(delegate);
}

#if BUILDFLAG(IS_WIN)
base::Lock& FilePathWatcher::GetWatchThreadLockForTest() {
  return impl_->GetWatchThreadLockForTest();  // IN-TEST
}
#endif

size_t FilePathWatcher::current_usage() const {
  return impl_->current_usage();
}

// static
size_t FilePathWatcher::quota_limit() {
  if (FilePathWatcher::quota_limit_override_for_testing_ > 0) {
    return FilePathWatcher::quota_limit_override_for_testing_;
  }

  if (base::FeatureList::IsEnabled(
          features::kFileSystemAccessObserverQuotaLimit)) {
    return GetQuotaLimitImpl();
  }

  return std::numeric_limits<size_t>::max();
}

}  // namespace content