// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine License
// Agreement.

#include "device_files.h"

#include <inttypes.h>
#include <string.h>

#include <algorithm>
#include <string>

#include "cdm_random.h"
#include "certificate_provisioning.h"
#include "clock.h"
#include "file_store.h"
#include "license_protocol.pb.h"
#include "log.h"
#include "privacy_crypto.h"
#include "properties.h"
#include "string_conversions.h"
#include "wv_cdm_constants.h"

// Protobuf generated classes.
using video_widevine_client::sdk::DeviceCertificate;
using video_widevine_client::sdk::HashedFile;
using video_widevine_client::sdk::HlsAttributes;
using video_widevine_client::sdk::HlsAttributes_Method_AES_128;
using video_widevine_client::sdk::HlsAttributes_Method_SAMPLE_AES;
using video_widevine_client::sdk::License;
using video_widevine_client::sdk::License_LicenseState_ACTIVE;
using video_widevine_client::sdk::License_LicenseState_RELEASING;
using video_widevine_client::sdk::NameValue;
using video_widevine_client::sdk::UsageInfo;
using video_widevine_client::sdk::UsageInfo_DrmUsageCertificate;
using video_widevine_client::sdk::UsageInfo_ProviderSession;
using video_widevine_client::sdk::UsageTableInfo;
using video_widevine_client::sdk::UsageTableInfo_UsageEntryInfo;
using video_widevine_client::sdk::
    UsageTableInfo_UsageEntryInfo_UsageEntryStorage_LICENSE;
using video_widevine_client::sdk::
    UsageTableInfo_UsageEntryInfo_UsageEntryStorage_UNKNOWN;
using video_widevine_client::sdk::
    UsageTableInfo_UsageEntryInfo_UsageEntryStorage_USAGE_INFO;

// Stringify turns macro arguments into static C strings.
//   Example: STRINGIFY(this_argument) -> "this_argument"
#define STRINGIFY(PARAM...) #PARAM

#define RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_NULL(PARAM)     \
  if ((PARAM) == nullptr) {                                       \
    LOGE("Output parameter |" STRINGIFY(PARAM) "| not provided"); \
    return DeviceFiles::kCannotHandle;                            \
  }

#define RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_UNINITIALIZED() \
  if (!initialized_) {                                            \
    LOGE("Device files is not initialized");                      \
    return DeviceFiles::kCannotHandle;                            \
  }

#define RETURN_FALSE_IF_NULL(PARAM)                               \
  if ((PARAM) == nullptr) {                                       \
    LOGE("Output parameter |" STRINGIFY(PARAM) "| not provided"); \
    return false;                                                 \
  }

#define RETURN_FALSE_WITH_RESULT_IF_NULL(PARAM, result)           \
  if ((PARAM) == nullptr) {                                       \
    LOGE("Output parameter |" STRINGIFY(PARAM) "| not provided"); \
    *result = kParameterNull;                                     \
    return false;                                                 \
  }

#define RETURN_FALSE_IF_UNINITIALIZED()      \
  if (!initialized_) {                       \
    LOGE("Device files is not initialized"); \
    return false;                            \
  }

#define RETURN_FALSE_WITH_RESULT_IF_UNINITIALIZED(result) \
  if (!initialized_) {                                    \
    LOGE("Device files is not initialized");              \
    *result = kObjectNotInitialized;                      \
    return false;                                         \
  }

namespace {

const char kEmptyFileName[] = "";
const char kFalse[] = "false";
const char kHlsAttributesFileNameExt[] = ".hal";
const char kLicenseFileNameExt[] = ".lic";
const char kTrue[] = "true";
const char kUsageInfoFileNameExt[] = ".bin";
const char kUsageInfoFileNamePrefix[] = "usage";
const char kUsageTableFileName[] = "usgtable.bin";
const char kWildcard[] = "*";
constexpr int64_t kFourMonthsInSeconds = (2 * 30 + 2 * 31) * 24 * 60 * 60;

// Helper methods
bool SetDeviceCertificate(const std::string& certificate,
                          const wvcdm::CryptoWrappedKey& private_key,
                          DeviceCertificate* mutable_device_certificate) {
  RETURN_FALSE_IF_NULL(mutable_device_certificate);

  mutable_device_certificate->set_certificate(certificate);
  mutable_device_certificate->set_wrapped_private_key(private_key.key());
  switch (private_key.type()) {
    case wvcdm::CryptoWrappedKey::kRsa:
      mutable_device_certificate->set_key_type(DeviceCertificate::RSA);
      return true;
    case wvcdm::CryptoWrappedKey::kEcc:
      mutable_device_certificate->set_key_type(DeviceCertificate::ECC);
      return true;
    case wvcdm::CryptoWrappedKey::kUninitialized:  // Suppress compiler
                                                   // warnings.
    default:
      LOGE("Unexpected key type: %d", private_key.type());
      return false;
  }
}

bool ExtractFromDeviceCertificate(const DeviceCertificate& device_certificate,
                                  std::string* certificate,
                                  wvcdm::CryptoWrappedKey* private_key) {
  RETURN_FALSE_IF_NULL(certificate);
  RETURN_FALSE_IF_NULL(private_key);

  const bool has_certificate = device_certificate.has_certificate();
  const bool has_key = device_certificate.has_wrapped_private_key();

  // If no certificate information, nothing to be done. DeviceCertificate
  // is a legacy DRM certificate
  if (!has_certificate && !has_key) return true;

  // Flag if not a default certificate
  if (!has_certificate || !has_key) {
    LOGE(
        "Device certificate proto belongs to neither a default or legacy cert. "
        "has_certificate: %s, has_key: %s",
        has_certificate ? kTrue : kFalse, has_key ? kTrue : kFalse);
    return false;
  }

  if (device_certificate.certificate().empty() ||
      device_certificate.wrapped_private_key().empty()) {
    LOGE(
        "Device certificate proto belongs does not have a valid certificate or "
        "wrapped key. certificate size: %zu, wrapped key size: %zu",
        device_certificate.certificate().size(),
        device_certificate.wrapped_private_key().size());
    return false;
  }

  *certificate = device_certificate.certificate();
  private_key->Clear();
  private_key->set_key(device_certificate.wrapped_private_key());
  if (device_certificate.has_key_type()) {
    const DeviceCertificate::PrivateKeyType key_type =
        device_certificate.key_type();
    switch (key_type) {
      case DeviceCertificate::RSA:
        private_key->set_type(wvcdm::CryptoWrappedKey::kRsa);
        break;
      case DeviceCertificate::ECC:
        private_key->set_type(wvcdm::CryptoWrappedKey::kEcc);
        break;
      default:
        LOGW("Unknown DRM key type, defaulting to RSA: type = %d", key_type);
        private_key->set_type(wvcdm::CryptoWrappedKey::kRsa);
        break;
    }
  } else {
    // Possible that device certificate is from V15, in this case, the
    // only supported key of at that time was RSA.
    LOGD("No key type info, assuming RSA");
    private_key->set_type(wvcdm::CryptoWrappedKey::kRsa);
  }
  return true;
}

bool FindOrInsertUsageCertificate(
    const std::string& drm_certificate,
    const wvcdm::CryptoWrappedKey& wrapped_private_key, UsageInfo* usage_info,
    uint32_t* drm_certificate_id) {
  RETURN_FALSE_IF_NULL(usage_info);
  RETURN_FALSE_IF_NULL(drm_certificate_id);

  // Scan |drm_certificate_cache| for |drm_certificate|. If present,
  // return the id
  std::set<uint32_t> ids;
  for (const UsageInfo_DrmUsageCertificate& drm_device_cert :
       usage_info->drm_certificate_cache()) {
    if (drm_device_cert.drm_certificate().certificate() == drm_certificate) {
      *drm_certificate_id = drm_device_cert.drm_certificate_id();
      return true;
    }
    ids.insert(drm_device_cert.drm_certificate_id());
  }

  uint32_t last_id = 0;

  // |drm_certificate| is not in the cache. Find the first non-contiguous
  // id number to insert
  for (uint32_t id : ids) {
    if (id > last_id + 1) {
      break;
    }
    last_id = id;
  }

  if (ids.empty())
    *drm_certificate_id = 0;
  else
    *drm_certificate_id = last_id + 1;

  // Now insert into |drm_certificate_cache|
  UsageInfo_DrmUsageCertificate* drm_usage_certificate =
      usage_info->add_drm_certificate_cache();
  drm_usage_certificate->set_drm_certificate_id(*drm_certificate_id);

  return SetDeviceCertificate(drm_certificate, wrapped_private_key,
                              drm_usage_certificate->mutable_drm_certificate());
}

bool FindUsageCertificate(
    uint32_t drm_certificate_id,
    const google::protobuf::RepeatedPtrField<UsageInfo_DrmUsageCertificate>&
        drm_certificate_cache,
    std::string* drm_certificate,
    wvcdm::CryptoWrappedKey* wrapped_private_key) {
  for (const UsageInfo_DrmUsageCertificate& drm_usage_cert :
       drm_certificate_cache) {
    if (drm_usage_cert.drm_certificate_id() == drm_certificate_id) {
      return ExtractFromDeviceCertificate(drm_usage_cert.drm_certificate(),
                                          drm_certificate, wrapped_private_key);
    }
  }

  LOGE("Unable to find any certificate in usage cache for entry: %d",
       drm_certificate_id);
  return false;
}

bool UsageCertificateCacheCleanUp(UsageInfo* usage_info) {
  const google::protobuf::RepeatedPtrField<UsageInfo_ProviderSession>&
      provider_sessions = usage_info->sessions();
  google::protobuf::RepeatedPtrField<UsageInfo_DrmUsageCertificate>*
      drm_certificate_cache = usage_info->mutable_drm_certificate_cache();

  // Find all the DRM certificate ids in |drm_certificate_cache|
  std::set<uint32_t> ids;
  for (const UsageInfo_DrmUsageCertificate& drm_usage_cert :
       *drm_certificate_cache) {
    ids.insert(drm_usage_cert.drm_certificate_id());
  }

  // Next find all the DRM certificate ids in |provider_sessions|
  std::set<uint32_t> session_ids;
  for (const UsageInfo_ProviderSession& session : provider_sessions) {
    session_ids.insert(session.drm_certificate_id());
  }

  // Now find all the entry numbers for DRM certificates in
  // |drm_device_certificates| but not in |provider_sessions|. These need to
  // be removed.
  std::set<uint32_t> ids_to_erase;
  std::set_difference(ids.begin(), ids.end(), session_ids.begin(),
                      session_ids.end(),
                      std::inserter(ids_to_erase, ids_to_erase.begin()));

  const auto is_deletable =
      [&ids_to_erase](
          const UsageInfo_DrmUsageCertificate& usage_certificate) -> bool {
    return std::find(ids_to_erase.cbegin(), ids_to_erase.cend(),
                     usage_certificate.drm_certificate_id()) !=
           ids_to_erase.cend();
  };

  drm_certificate_cache->erase(
      std::remove_if(drm_certificate_cache->begin(),
                     drm_certificate_cache->end(), is_deletable),
      drm_certificate_cache->end());

  return true;
}

}  // namespace

namespace wvcdm {

// static
std::set<std::string> DeviceFiles::reserved_license_ids_;

DeviceFiles::DeviceFiles(FileSystem* file_system)
    : file_system_(file_system),
      security_level_(kSecurityLevelUninitialized),
      initialized_(false) {}

DeviceFiles::~DeviceFiles() {}

bool DeviceFiles::Init(CdmSecurityLevel security_level) {
  if (!file_system_) {
    LOGE("Invalid FileSystem given");
    return false;
  }

  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level, &path)) {
    LOGE("Unsupported security level: %d", security_level);
    return false;
  }
  security_level_ = security_level;
  initialized_ = true;
  return true;
}

bool DeviceFiles::StoreCertificate(const std::string& certificate,
                                   const CryptoWrappedKey& private_key) {
  RETURN_FALSE_IF_UNINITIALIZED();
  if (certificate.empty()) {
    LOGE("Missing certificate information");
    return false;
  }
  if (!private_key.IsValid()) {
    LOGE("Private key is invalid");
    return false;
  }

  // Fill in file information
  video_widevine_client::sdk::File file;

  file.set_type(video_widevine_client::sdk::File::DEVICE_CERTIFICATE);
  file.set_version(video_widevine_client::sdk::File::VERSION_1);

  DeviceCertificate* device_certificate = file.mutable_device_certificate();

  int64_t creation_time_seconds;
  int64_t expiration_time_seconds;
  uint32_t system_id;

  if (!CertificateProvisioning::ExtractDeviceInfo(
          certificate, nullptr, &system_id, &creation_time_seconds,
          &expiration_time_seconds))
    return false;

  if (creation_time_seconds <= 0) {
    LOGE("Invalid certificate creation time %" PRId64, creation_time_seconds);
    return false;
  }

  const bool default_certificate = expiration_time_seconds >= 0;

  if (!SetDeviceCertificate(certificate, private_key, device_certificate))
    return false;

  if (default_certificate) {
    Clock clock;
    device_certificate->set_acquisition_time_seconds(clock.GetCurrentTime());
  } else {
    // Since certificates of type kCertificateAtsc are not allowed to be
    // stored, this is a certificate of type kCertificateLegacy.
    // The only time when a legacy certificate is stored is when it does not
    // have an expiration time. Set expiration time to 6 months +- 2 months.
    Clock clock;
    const int64_t current_time = clock.GetCurrentTime();
    CdmRandomGenerator rng(current_time & 0xffffffff);

    device_certificate->set_expiration_time_seconds(
        current_time + kFourMonthsInSeconds +
        rng.RandomInRange(kFourMonthsInSeconds));
  }

  std::string serialized_file;
  file.SerializeToString(&serialized_file);

  std::string certificate_file_name;
  const CertificateType certificate_type =
      default_certificate ? kCertificateDefault : kCertificateLegacy;
  if (!GetCertificateFileName(certificate_type, &certificate_file_name)) {
    LOGE("Unable to get certificate file name of type: %d", certificate_type);
    return false;
  }
  return StoreFileWithHash(certificate_file_name, serialized_file) == kNoError;
}

DeviceFiles::CertificateState DeviceFiles::RetrieveCertificate(
    bool atsc_mode_enabled, std::string* certificate,
    CryptoWrappedKey* private_key, std::string* serial_number,
    uint32_t* system_id) {
  RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_UNINITIALIZED();
  RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_NULL(certificate);
  RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_NULL(private_key);

  if (!HasCertificate(atsc_mode_enabled)) {
    LOGW("Unable to find certificate, atsc mode: %s",
         atsc_mode_enabled ? "enabled" : "disabled");
    return kCertificateNotFound;
  }

  if (atsc_mode_enabled)
    return RetrieveCertificate(kCertificateAtsc, certificate, private_key,
                               serial_number, system_id);

  if (HasCertificate(kCertificateDefault))
    return RetrieveCertificate(kCertificateDefault, certificate, private_key,
                               serial_number, system_id);

  return RetrieveCertificate(kCertificateLegacy, certificate, private_key,
                             serial_number, system_id);
}

DeviceFiles::CertificateState DeviceFiles::RetrieveCertificate(
    CertificateType certificate_type, std::string* certificate,
    CryptoWrappedKey* wrapped_private_key, std::string* serial_number,
    uint32_t* system_id) {
  RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_NULL(certificate);
  RETURN_CERTIFICATE_STATE_CANNOT_HANDLE_IF_NULL(wrapped_private_key);

  std::string certificate_file_name;
  if (!GetCertificateFileName(certificate_type, &certificate_file_name)) {
    LOGW("Unable to find certificate file name for type: %d", certificate_type);
    return kCannotHandle;
  }

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(certificate_file_name, &file) != kNoError) {
    LOGW("Unable to retrieve certificate file");
    return kCertificateNotFound;
  }

  if (file.type() != video_widevine_client::sdk::File::DEVICE_CERTIFICATE) {
    LOGE("Certificate file is of incorrect file type: type = %d",
         static_cast<int>(file.type()));
    return kCertificateInvalid;
  }

  if (file.version() != video_widevine_client::sdk::File::VERSION_1) {
    LOGE("Certificate file is of incorrect file version: version = %d",
         static_cast<int>(file.version()));
    return kCertificateInvalid;
  }

  if (!file.has_device_certificate()) {
    LOGE("Certificate not present");
    return kCertificateInvalid;
  }

  const DeviceCertificate& device_certificate = file.device_certificate();

  if (!ExtractFromDeviceCertificate(device_certificate, certificate,
                                    wrapped_private_key)) {
    LOGE("Unable to extract from device certificate");
    return kCertificateInvalid;
  }

  int64_t creation_time_seconds;
  int64_t expiration_time_seconds;

  if (!CertificateProvisioning::ExtractDeviceInfo(
          device_certificate.certificate(), serial_number, system_id,
          &creation_time_seconds, &expiration_time_seconds))
    return kCertificateInvalid;

  Clock clock;
  const int64_t current_time = clock.GetCurrentTime();

  switch (certificate_type) {
    case kCertificateDefault: {
      // Validation check for DRM certificate that includes an expiration
      // time set by the provisioning service. Since provisioning and
      // client clocks may not be in sync, verify by comparing time
      // elapsed since the certificate was acquired with the expiration
      // period specified by the service.
      // First verify that all the fields are set to valid values.
      // The service will validate certificate expiration so tampering of
      // time values at the client is not a concern.
      if (creation_time_seconds <= 0) {
        LOGE("Invalid creation time of default certificate: %" PRId64,
             creation_time_seconds);
        return kCertificateInvalid;
      }
      if (expiration_time_seconds < 0) {
        LOGE("Invalid expiration time of default certificate: %" PRId64,
             expiration_time_seconds);
        return kCertificateInvalid;
      }
      if (expiration_time_seconds == UNLIMITED_DURATION)
        return kCertificateValid;

      if (!device_certificate.has_acquisition_time_seconds()) {
        LOGE("Acquisition time of default certificate not available");
        return kCertificateInvalid;
      }
      const int64_t acquisition_time_seconds =
          device_certificate.acquisition_time_seconds();
      if (acquisition_time_seconds <= 0) {
        LOGE("Invalid acquisition time of default certificate: %" PRId64,
             acquisition_time_seconds);
        return kCertificateInvalid;
      }

      if (current_time < acquisition_time_seconds) {
        LOGE("Time not valid: current time: %" PRId64
             ", acquisition time: %" PRId64,
             current_time, acquisition_time_seconds);
        return kCannotHandle;
      }

      if (expiration_time_seconds < creation_time_seconds) {
        LOGE("Time not valid: expiration time: %" PRId64
             ", creation time: %" PRId64,
             expiration_time_seconds, creation_time_seconds);
        return kCertificateInvalid;
      }

      // |current_time| and |acquisition_time_seconds| are client clock
      // times while |expiration_time_seconds| and |creation_time_seconds|
      // are times specified by the provisioning service
      if (current_time - acquisition_time_seconds >
          expiration_time_seconds - creation_time_seconds) {
        return kCertificateExpired;
      }
      return kCertificateValid;
    }

    case kCertificateLegacy: {
      // Validation check for DRM certificate without an expiration
      // time set by the provisioning service. Add an expiry time
      // within the next 6 months +/- 2 months, if one has not been set.
      if (!device_certificate.has_expiration_time_seconds()) {
        StoreCertificate(*certificate, *wrapped_private_key);
        return kCertificateValid;
      }
      const int64_t expiration_time_seconds =
          device_certificate.expiration_time_seconds();
      if (expiration_time_seconds <= 0) {
        LOGE("Invalid expiration time of legacy certificate: %" PRId64,
             expiration_time_seconds);
        return kCertificateInvalid;
      }

      if (current_time > expiration_time_seconds) return kCertificateExpired;

      return kCertificateValid;
    }

    case kCertificateAtsc:
      // No expiration enforced
      return kCertificateValid;

    default:
      // Should never happen. This should be detected earlier when fetching
      // the file name
      LOGE("Invalid certificate type: %d", certificate_type);
      return kCertificateInvalid;
  }
}

bool DeviceFiles::RetrieveLegacyCertificate(std::string* certificate,
                                            CryptoWrappedKey* private_key,
                                            std::string* serial_number,
                                            uint32_t* system_id) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(certificate);
  RETURN_FALSE_IF_NULL(private_key);
  if (!HasCertificate(kCertificateLegacy)) return false;

  const CertificateState state = RetrieveCertificate(
      kCertificateLegacy, certificate, private_key, serial_number, system_id);
  if (state == kCertificateValid || state == kCertificateExpired) return true;

  return false;
}

bool DeviceFiles::HasCertificate(bool atsc_mode_enabled) {
  RETURN_FALSE_IF_UNINITIALIZED();

  if (atsc_mode_enabled) return HasCertificate(kCertificateAtsc);

  return HasCertificate(kCertificateDefault) ||
         HasCertificate(kCertificateLegacy);
}

bool DeviceFiles::RemoveCertificate() {
  RETURN_FALSE_IF_UNINITIALIZED()

  std::string certificate_file_name;
  if (GetCertificateFileName(kCertificateLegacy, &certificate_file_name))
    RemoveFile(certificate_file_name);
  if (GetCertificateFileName(kCertificateDefault, &certificate_file_name))
    return RemoveFile(certificate_file_name);
  return true;
}

bool DeviceFiles::StoreLicense(const CdmLicenseData& license_data,
                               ResponseType* result) {
  RETURN_FALSE_IF_NULL(result);

  *result = kNoError;
  RETURN_FALSE_WITH_RESULT_IF_UNINITIALIZED(result);

  // Fill in file information
  video_widevine_client::sdk::File file;

  file.set_type(video_widevine_client::sdk::File::LICENSE);
  file.set_version(video_widevine_client::sdk::File::VERSION_1);

  License* license = file.mutable_license();
  switch (license_data.state) {
    case kLicenseStateActive:
      license->set_state(License_LicenseState_ACTIVE);
      break;
    case kLicenseStateReleasing:
      license->set_state(License_LicenseState_RELEASING);
      break;
    default:
      LOGE("Unknown license state: %d", static_cast<int>(license_data.state));
      *result = kUnknownLicenseState;
      return false;
      break;
  }
  license->set_pssh_data(license_data.pssh_data);
  license->set_license_request(license_data.license_request);
  license->set_license(license_data.license);
  license->set_renewal_request(license_data.license_renewal_request);
  license->set_renewal(license_data.license_renewal);
  license->set_release_server_url(license_data.release_server_url);
  license->set_playback_start_time(license_data.playback_start_time);
  license->set_last_playback_time(license_data.last_playback_time);
  license->set_grace_period_end_time(license_data.grace_period_end_time);
  for (CdmAppParameterMap::const_iterator iter =
           license_data.app_parameters.cbegin();
       iter != license_data.app_parameters.cend(); ++iter) {
    NameValue* app_params = license->add_app_parameters();
    app_params->set_name(iter->first);
    app_params->set_value(iter->second);
  }
  license->set_usage_entry(license_data.usage_entry);
  license->set_usage_entry_number(license_data.usage_entry_number);
  if (!license_data.drm_certificate.empty()) {
    DeviceCertificate* device_certificate = license->mutable_drm_certificate();
    if (!SetDeviceCertificate(license_data.drm_certificate,
                              license_data.wrapped_private_key,
                              device_certificate))
      return false;
  }

  std::string serialized_file;
  file.SerializeToString(&serialized_file);

  reserved_license_ids_.erase(license_data.key_set_id);
  *result = StoreFileWithHash(license_data.key_set_id + kLicenseFileNameExt,
                              serialized_file);
  return *result == kNoError;
}

bool DeviceFiles::RetrieveLicense(const std::string& key_set_id,
                                  CdmLicenseData* license_data,
                                  ResponseType* result) {
  // This check must be made first as the RETURN_FALSE_IF_NULL() macro
  // will assign kParameterNull to |result|.
  if (result == nullptr) {
    LOGE("Output parameter |result| not provided");
    return false;
  }
  RETURN_FALSE_WITH_RESULT_IF_UNINITIALIZED(result);
  RETURN_FALSE_WITH_RESULT_IF_NULL(license_data, result);

  video_widevine_client::sdk::File file;
  *result = RetrieveHashedFile(key_set_id + kLicenseFileNameExt, &file);
  if (*result != kNoError) {
    LOGE("Unable to retrieve key set license file: result = %d",
         static_cast<int>(*result));
    return false;
  }

  if (file.type() != video_widevine_client::sdk::File::LICENSE) {
    LOGE("Incorrect file type: type = %d, expected_type = %d",
         static_cast<int>(file.type()),
         static_cast<int>(video_widevine_client::sdk::File::LICENSE));
    *result = kIncorrectFileType;
    return false;
  }

  if (file.version() != video_widevine_client::sdk::File::VERSION_1) {
    LOGE("Incorrect file version: version = %d, expected_version = %d",
         static_cast<int>(file.version()),
         static_cast<int>(video_widevine_client::sdk::File::VERSION_1));
    *result = kIncorrectFileVersion;
    return false;
  }

  if (!file.has_license()) {
    LOGE("License not present");
    *result = kLicenseNotPresent;
    return false;
  }

  license_data->key_set_id = key_set_id;

  License license = file.license();

  switch (license.state()) {
    case License_LicenseState_ACTIVE:
      license_data->state = kLicenseStateActive;
      break;
    case License_LicenseState_RELEASING:
      license_data->state = kLicenseStateReleasing;
      break;
    default:
      LOGW("Unrecognized license state: %d", static_cast<int>(license.state()));
      license_data->state = kLicenseStateUnknown;
      break;
  }
  license_data->pssh_data = license.pssh_data();
  license_data->license_request = license.license_request();
  license_data->license = license.license();
  license_data->license_renewal_request = license.renewal_request();
  license_data->license_renewal = license.renewal();
  license_data->release_server_url = license.release_server_url();
  license_data->playback_start_time = license.playback_start_time();
  license_data->last_playback_time = license.last_playback_time();
  license_data->grace_period_end_time = license.grace_period_end_time();
  for (int i = 0; i < license.app_parameters_size(); ++i) {
    license_data->app_parameters[license.app_parameters(i).name()] =
        license.app_parameters(i).value();
  }
  license_data->usage_entry = license.usage_entry();
  license_data->usage_entry_number = license.usage_entry_number();

  if (!license.has_drm_certificate()) {
    license_data->drm_certificate.clear();
    license_data->wrapped_private_key.Clear();
    return true;
  }

  return ExtractFromDeviceCertificate(license.drm_certificate(),
                                      &license_data->drm_certificate,
                                      &license_data->wrapped_private_key);
}

bool DeviceFiles::DeleteLicense(const std::string& key_set_id) {
  RETURN_FALSE_IF_UNINITIALIZED();
  return RemoveFile(key_set_id + kLicenseFileNameExt);
}

bool DeviceFiles::ListLicenses(std::vector<std::string>* key_set_ids) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(key_set_ids);

  // Get list of filenames
  std::vector<std::string> filenames;
  if (!ListFiles(&filenames)) {
    return false;
  }

  // Scan list of returned filenames, remove extension, and return
  // as a list of key_set_ids.
  key_set_ids->clear();
  for (size_t i = 0; i < filenames.size(); i++) {
    std::string* name = &filenames[i];
    std::size_t pos = name->find(kLicenseFileNameExt);
    if (pos == std::string::npos) {
      // Skip this file - extension does not match
      continue;
    }
    // Store filename (minus extension).  This should be a key set ID.
    key_set_ids->push_back(name->substr(0, pos));
  }
  return true;
}

bool DeviceFiles::DeleteAllLicenses() {
  RETURN_FALSE_IF_UNINITIALIZED();
  return RemoveFile(std::string(kWildcard) + kLicenseFileNameExt);
}

bool DeviceFiles::DeleteAllFiles() {
  RETURN_FALSE_IF_UNINITIALIZED();
  // We pass an empty string to RemoveFile to delete the device files base
  // directory itself.
  return RemoveFile(kEmptyFileName);
}

bool DeviceFiles::LicenseExists(const std::string& key_set_id) {
  RETURN_FALSE_IF_UNINITIALIZED();
  return reserved_license_ids_.count(key_set_id) ||
         FileExists(key_set_id + kLicenseFileNameExt);
}

bool DeviceFiles::ReserveLicenseId(const std::string& key_set_id) {
  RETURN_FALSE_IF_UNINITIALIZED();
  reserved_license_ids_.insert(key_set_id);
  return true;
}

bool DeviceFiles::UnreserveLicenseId(const std::string& key_set_id) {
  RETURN_FALSE_IF_UNINITIALIZED();
  reserved_license_ids_.erase(key_set_id);
  return true;
}

bool DeviceFiles::StoreUsageInfo(
    const std::string& provider_session_token, const CdmKeyMessage& key_request,
    const CdmKeyResponse& key_response, const std::string& usage_info_file_name,
    const std::string& key_set_id, const std::string& usage_entry,
    uint32_t usage_entry_number, const std::string& drm_certificate,
    const CryptoWrappedKey& wrapped_private_key) {
  RETURN_FALSE_IF_UNINITIALIZED();
  video_widevine_client::sdk::File file;
  if (!FileExists(usage_info_file_name)) {
    file.set_type(video_widevine_client::sdk::File::USAGE_INFO);
    file.set_version(video_widevine_client::sdk::File::VERSION_1);
  } else {
    if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
      LOGE("Unable to retrieve usage info file");
      return false;
    }
  }

  UsageInfo* usage_info = file.mutable_usage_info();
  UsageInfo_ProviderSession* provider_session = usage_info->add_sessions();

  provider_session->set_token(provider_session_token.data(),
                              provider_session_token.size());
  provider_session->set_license_request(key_request.data(), key_request.size());
  provider_session->set_license(key_response.data(), key_response.size());
  provider_session->set_key_set_id(key_set_id.data(), key_set_id.size());
  provider_session->set_usage_entry(usage_entry);
  provider_session->set_usage_entry_number(usage_entry_number);

  if (drm_certificate.size() > 0) {
    uint32_t drm_certificate_id;
    if (!FindOrInsertUsageCertificate(drm_certificate, wrapped_private_key,
                                      usage_info, &drm_certificate_id)) {
      LOGE("Unable to insert a certificate in the usage certificate cache");
      return false;
    }
    provider_session->set_drm_certificate_id(drm_certificate_id);
  }

  std::string serialized_file;
  file.SerializeToString(&serialized_file);
  return StoreFileWithHash(usage_info_file_name, serialized_file) == kNoError;
}

bool DeviceFiles::ListUsageIds(
    const std::string& app_id, std::vector<std::string>* ksids,
    std::vector<std::string>* provider_session_tokens) {
  RETURN_FALSE_IF_UNINITIALIZED();

  if (ksids == nullptr && provider_session_tokens == nullptr) {
    LOGE(
        "Both output parameters |ksids| and |provider_session_tokens| are "
        "not provided");
    return false;
  }

  // Empty or non-existent file == no usage records.
  std::string file_name = GetUsageInfoFileName(app_id);
  if (!FileExists(file_name) || GetFileSize(file_name) == 0) {
    if (ksids != nullptr) ksids->clear();
    if (provider_session_tokens != nullptr) provider_session_tokens->clear();
    return true;
  }

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  if (ksids != nullptr) ksids->clear();
  if (provider_session_tokens != nullptr) provider_session_tokens->clear();

  size_t num_records = file.usage_info().sessions_size();
  for (size_t i = 0; i < num_records; ++i) {
    if ((ksids != nullptr) &&
        !file.usage_info().sessions(i).key_set_id().empty()) {
      ksids->push_back(file.usage_info().sessions(i).key_set_id());
    }
    if ((provider_session_tokens != nullptr) &&
        !file.usage_info().sessions(i).token().empty()) {
      provider_session_tokens->push_back(file.usage_info().sessions(i).token());
    }
  }
  return true;
}

bool DeviceFiles::GetProviderSessionToken(const std::string& app_id,
                                          const std::string& key_set_id,
                                          std::string* provider_session_token) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(provider_session_token);

  std::string file_name = GetUsageInfoFileName(app_id);
  if (!FileExists(file_name) || GetFileSize(file_name) == 0) {
    LOGE("Usage info file does not exists or is an empty file");
    return false;
  }

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  size_t num_records = file.usage_info().sessions_size();
  for (size_t i = 0; i < num_records; ++i) {
    if (file.usage_info().sessions(i).key_set_id() == key_set_id) {
      *provider_session_token = file.usage_info().sessions(i).token();
      return true;
    }
  }
  return false;
}

bool DeviceFiles::DeleteUsageInfo(const std::string& usage_info_file_name,
                                  const std::string& provider_session_token) {
  RETURN_FALSE_IF_UNINITIALIZED();
  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  UsageInfo* usage_info = file.mutable_usage_info();
  int index = 0;
  bool found = false;
  for (; index < usage_info->sessions_size(); ++index) {
    if (usage_info->sessions(index).token() == provider_session_token) {
      found = true;
      break;
    }
  }

  if (!found) {
    LOGE("Unable to find provider session token: pst = %s",
         b2a_hex(provider_session_token).c_str());
    return false;
  }

  google::protobuf::RepeatedPtrField<UsageInfo_ProviderSession>* sessions =
      usage_info->mutable_sessions();
  if (index < usage_info->sessions_size() - 1) {
    sessions->SwapElements(index, usage_info->sessions_size() - 1);
  }
  sessions->RemoveLast();
  UsageCertificateCacheCleanUp(usage_info);

  std::string serialized_file;
  file.SerializeToString(&serialized_file);
  return StoreFileWithHash(usage_info_file_name, serialized_file) == kNoError;
}

bool DeviceFiles::DeleteAllUsageInfoForApp(
    const std::string& usage_info_file_name,
    std::vector<std::string>* provider_session_tokens) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(provider_session_tokens);

  provider_session_tokens->clear();

  if (!FileExists(usage_info_file_name)) return true;

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) == kNoError) {
    for (int i = 0; i < file.usage_info().sessions_size(); ++i) {
      provider_session_tokens->push_back(file.usage_info().sessions(i).token());
    }
  } else {
    LOGW("Unable to retrieve usage info file");
  }
  return RemoveFile(usage_info_file_name);
}

bool DeviceFiles::DeleteMultipleUsageInfoByKeySetIds(
    const std::string& usage_info_file_name,
    const std::vector<std::string>& key_set_ids) {
  if (!FileExists(usage_info_file_name)) return false;
  if (key_set_ids.empty()) {
    LOGW("No key set IDs provided");
    return true;
  }

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGW("Unable to retrieve usage info file");
    return false;
  }

  const auto is_deletable =
      [&key_set_ids](
          const video_widevine_client::sdk::UsageInfo::ProviderSession& session)
      -> bool {
    return std::find(key_set_ids.cbegin(), key_set_ids.cend(),
                     session.key_set_id()) != key_set_ids.cend();
  };

  auto sessions = file.mutable_usage_info()->mutable_sessions();
  const int initial_size = sessions->size();
  sessions->erase(
      std::remove_if(sessions->begin(), sessions->end(), is_deletable),
      sessions->end());

  if (sessions->size() == initial_size) {
    // Nothing deleted.
    return true;
  }

  if (sessions->size() > 0) {
    UsageCertificateCacheCleanUp(file.mutable_usage_info());
    std::string serialized_file;
    file.SerializeToString(&serialized_file);
    return StoreFileWithHash(usage_info_file_name, serialized_file) == kNoError;
  }

  return RemoveFile(usage_info_file_name);
}

bool DeviceFiles::DeleteAllUsageInfo() {
  RETURN_FALSE_IF_UNINITIALIZED();
  return RemoveFile(kUsageInfoFileNamePrefix + std::string(kWildcard) +
                    kUsageInfoFileNameExt);
}

bool DeviceFiles::RetrieveUsageInfo(const std::string& usage_info_file_name,
                                    const std::string& provider_session_token,
                                    CdmKeyMessage* license_request,
                                    CdmKeyResponse* license,
                                    std::string* usage_entry,
                                    uint32_t* usage_entry_number,
                                    std::string* drm_certificate,
                                    CryptoWrappedKey* wrapped_private_key) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(license_request);
  RETURN_FALSE_IF_NULL(license);
  RETURN_FALSE_IF_NULL(usage_entry);
  RETURN_FALSE_IF_NULL(usage_entry_number);
  RETURN_FALSE_IF_NULL(drm_certificate);
  RETURN_FALSE_IF_NULL(wrapped_private_key);

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  int index = 0;
  for (; index < file.usage_info().sessions_size(); ++index) {
    if (file.usage_info().sessions(index).token() == provider_session_token) {
      *license_request = file.usage_info().sessions(index).license_request();
      *license = file.usage_info().sessions(index).license();
      *usage_entry = file.usage_info().sessions(index).usage_entry();
      *usage_entry_number =
          file.usage_info().sessions(index).usage_entry_number();

      if (!file.usage_info().sessions(index).has_drm_certificate_id()) {
        drm_certificate->clear();
        wrapped_private_key->Clear();
        return true;
      }

      if (!FindUsageCertificate(
              file.usage_info().sessions(index).drm_certificate_id(),
              file.usage_info().drm_certificate_cache(), drm_certificate,
              wrapped_private_key)) {
        LOGE("Unable to find DRM certificate information from usage cache");
        return false;
      }
      return true;
    }
  }

  return false;
}

bool DeviceFiles::RetrieveUsageInfoByKeySetId(
    const std::string& usage_info_file_name, const std::string& key_set_id,
    std::string* provider_session_token, CdmKeyMessage* license_request,
    CdmKeyResponse* license, std::string* usage_entry,
    uint32_t* usage_entry_number, std::string* drm_certificate,
    CryptoWrappedKey* wrapped_private_key) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(license_request);
  RETURN_FALSE_IF_NULL(license);
  RETURN_FALSE_IF_NULL(usage_entry);
  RETURN_FALSE_IF_NULL(usage_entry_number);
  RETURN_FALSE_IF_NULL(drm_certificate);
  RETURN_FALSE_IF_NULL(wrapped_private_key);

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  int index = 0;
  for (; index < file.usage_info().sessions_size(); ++index) {
    if (file.usage_info().sessions(index).key_set_id() == key_set_id) {
      *provider_session_token = file.usage_info().sessions(index).token();
      *license_request = file.usage_info().sessions(index).license_request();
      *license = file.usage_info().sessions(index).license();
      *usage_entry = file.usage_info().sessions(index).usage_entry();
      *usage_entry_number =
          file.usage_info().sessions(index).usage_entry_number();

      if (!file.usage_info().sessions(index).has_drm_certificate_id()) {
        drm_certificate->clear();
        wrapped_private_key->Clear();
        return true;
      }

      if (!FindUsageCertificate(
              file.usage_info().sessions(index).drm_certificate_id(),
              file.usage_info().drm_certificate_cache(), drm_certificate,
              wrapped_private_key)) {
        LOGE("Unable to find DRM certificate information from usage cache");
        return false;
      }
      return true;
    }
  }

  return false;
}

bool DeviceFiles::StoreUsageInfo(const std::string& usage_info_file_name,
                                 const std::vector<CdmUsageData>& usage_data) {
  RETURN_FALSE_IF_UNINITIALIZED();

  video_widevine_client::sdk::File file;
  file.set_type(video_widevine_client::sdk::File::USAGE_INFO);
  file.set_version(video_widevine_client::sdk::File::VERSION_1);

  UsageInfo* usage_info = file.mutable_usage_info();

  for (size_t i = 0; i < usage_data.size(); ++i) {
    UsageInfo_ProviderSession* provider_session = usage_info->add_sessions();

    provider_session->set_token(usage_data[i].provider_session_token.data(),
                                usage_data[i].provider_session_token.size());
    provider_session->set_license_request(usage_data[i].license_request.data(),
                                          usage_data[i].license_request.size());
    provider_session->set_license(usage_data[i].license.data(),
                                  usage_data[i].license.size());
    provider_session->set_key_set_id(usage_data[i].key_set_id.data(),
                                     usage_data[i].key_set_id.size());
    provider_session->set_usage_entry(usage_data[i].usage_entry);
    provider_session->set_usage_entry_number(usage_data[i].usage_entry_number);

    if (usage_data[i].drm_certificate.size() > 0) {
      uint32_t drm_certificate_id;
      if (!FindOrInsertUsageCertificate(usage_data[i].drm_certificate,
                                        usage_data[i].wrapped_private_key,
                                        usage_info, &drm_certificate_id)) {
        LOGE("Unable to insert a certificate in the usage certificate cache");
        return false;
      }
      provider_session->set_drm_certificate_id(drm_certificate_id);
    }
  }

  std::string serialized_file;
  file.SerializeToString(&serialized_file);
  return StoreFileWithHash(usage_info_file_name, serialized_file) == kNoError;
}

bool DeviceFiles::UpdateUsageInfo(const std::string& usage_info_file_name,
                                  const std::string& provider_session_token,
                                  const CdmUsageData& usage_data) {
  RETURN_FALSE_IF_UNINITIALIZED();

  video_widevine_client::sdk::File file;
  if (!FileExists(usage_info_file_name)) {
    LOGE("Usage info file does not exist");
    return false;
  }

  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  int index = 0;
  for (; index < file.usage_info().sessions_size(); ++index) {
    if (file.usage_info().sessions(index).token() == provider_session_token) {
      UsageInfo* usage_info = file.mutable_usage_info();
      UsageInfo_ProviderSession* provider_session =
          usage_info->mutable_sessions(index);
      provider_session->set_license_request(usage_data.license_request);
      provider_session->set_license(usage_data.license);
      provider_session->set_key_set_id(usage_data.key_set_id);
      provider_session->set_usage_entry(usage_data.usage_entry);
      provider_session->set_usage_entry_number(usage_data.usage_entry_number);

      if (usage_data.drm_certificate.size() > 0) {
        uint32_t drm_certificate_id;
        if (!FindOrInsertUsageCertificate(usage_data.drm_certificate,
                                          usage_data.wrapped_private_key,
                                          usage_info, &drm_certificate_id)) {
          LOGE("Unable to find a certificate in to update the usage info");
          return false;
        }
        provider_session->set_drm_certificate_id(drm_certificate_id);
      }

      std::string serialized_file;
      file.SerializeToString(&serialized_file);
      return StoreFileWithHash(usage_info_file_name, serialized_file) ==
             kNoError;
    }
  }

  return false;
}

bool DeviceFiles::RetrieveUsageInfo(const std::string& usage_info_file_name,
                                    std::vector<CdmUsageData>* usage_data) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(usage_data);

  if (!FileExists(usage_info_file_name) ||
      GetFileSize(usage_info_file_name) == 0) {
    usage_data->resize(0);
    return true;
  }

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  usage_data->resize(file.usage_info().sessions_size());
  for (int i = 0; i < file.usage_info().sessions_size(); ++i) {
    (*usage_data)[i].provider_session_token =
        file.usage_info().sessions(i).token();
    (*usage_data)[i].license_request =
        file.usage_info().sessions(i).license_request();
    (*usage_data)[i].license = file.usage_info().sessions(i).license();
    (*usage_data)[i].key_set_id = file.usage_info().sessions(i).key_set_id();
    (*usage_data)[i].usage_entry = file.usage_info().sessions(i).usage_entry();
    (*usage_data)[i].usage_entry_number =
        file.usage_info().sessions(i).usage_entry_number();

    if (!file.usage_info().sessions(i).has_drm_certificate_id()) {
      (*usage_data)[i].drm_certificate.clear();
      (*usage_data)[i].wrapped_private_key.Clear();
    } else {
      if (!FindUsageCertificate(
              file.usage_info().sessions(i).drm_certificate_id(),
              file.usage_info().drm_certificate_cache(),
              &(*usage_data)[i].drm_certificate,
              &(*usage_data)[i].wrapped_private_key)) {
        LOGW("Unable to find DRM certificate information from usage cache");
      }
    }
  }

  return true;
}

bool DeviceFiles::RetrieveUsageInfo(const std::string& usage_info_file_name,
                                    const std::string& provider_session_token,
                                    CdmUsageData* usage_data) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(usage_data);

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(usage_info_file_name, &file) != kNoError) {
    LOGE("Unable to retrieve usage info file");
    return false;
  }

  int index = 0;
  for (; index < file.usage_info().sessions_size(); ++index) {
    if (file.usage_info().sessions(index).token() == provider_session_token) {
      usage_data->provider_session_token =
          file.usage_info().sessions(index).token();
      usage_data->license_request =
          file.usage_info().sessions(index).license_request();
      usage_data->license = file.usage_info().sessions(index).license();
      usage_data->key_set_id = file.usage_info().sessions(index).key_set_id();
      usage_data->usage_entry = file.usage_info().sessions(index).usage_entry();
      usage_data->usage_entry_number =
          file.usage_info().sessions(index).usage_entry_number();

      if (!file.usage_info().sessions(index).has_drm_certificate_id()) {
        usage_data->drm_certificate.clear();
        usage_data->wrapped_private_key.Clear();
        return true;
      }

      if (!FindUsageCertificate(
              file.usage_info().sessions(index).drm_certificate_id(),
              file.usage_info().drm_certificate_cache(),
              &usage_data->drm_certificate, &usage_data->wrapped_private_key)) {
        LOGE("Unable to find DRM certificate information from usage cache");
        return false;
      }
      return true;
    }
  }

  return false;
}

bool DeviceFiles::ListUsageInfoFiles(
    std::vector<std::string>* usage_info_file_names) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(usage_info_file_names);

  // Get list of filenames
  std::vector<std::string> filenames;
  if (!ListFiles(&filenames)) {
    return false;
  }

  // Scan list of all filenames and return only usage info filenames
  usage_info_file_names->clear();
  for (size_t i = 0; i < filenames.size(); i++) {
    std::string* name = &filenames[i];
    std::size_t pos_prefix = name->find(kUsageInfoFileNamePrefix);
    std::size_t pos_suffix = name->find(kUsageInfoFileNameExt);
    if (pos_prefix == std::string::npos || pos_suffix == std::string::npos) {
      // Skip this file - extension does not match
      continue;
    }

    usage_info_file_names->push_back(*name);
  }
  return true;
}

bool DeviceFiles::StoreHlsAttributes(
    const std::string& key_set_id, const CdmHlsMethod method,
    const std::vector<uint8_t>& media_segment_iv) {
  RETURN_FALSE_IF_UNINITIALIZED();

  // Fill in file information
  video_widevine_client::sdk::File file;

  file.set_type(video_widevine_client::sdk::File::HLS_ATTRIBUTES);
  file.set_version(video_widevine_client::sdk::File::VERSION_1);

  HlsAttributes* hls_attributes = file.mutable_hls_attributes();
  switch (method) {
    case kHlsMethodAes128:
      hls_attributes->set_method(HlsAttributes_Method_AES_128);
      break;
    case kHlsMethodSampleAes:
      hls_attributes->set_method(HlsAttributes_Method_SAMPLE_AES);
      break;
    case kHlsMethodNone:
    default:
      LOGE("Unknown HLS method: %d", method);
      return false;
      break;
  }
  hls_attributes->set_media_segment_iv(&media_segment_iv[0],
                                       media_segment_iv.size());

  std::string serialized_file;
  file.SerializeToString(&serialized_file);

  return StoreFileWithHash(key_set_id + kHlsAttributesFileNameExt,
                           serialized_file) == kNoError;
}

bool DeviceFiles::RetrieveHlsAttributes(
    const std::string& key_set_id, CdmHlsMethod* method,
    std::vector<uint8_t>* media_segment_iv) {
  RETURN_FALSE_IF_UNINITIALIZED();

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(key_set_id + kHlsAttributesFileNameExt, &file) !=
      kNoError) {
    LOGE("Unable to retrieve key set HLS attributes file");
    return false;
  }

  if (file.type() != video_widevine_client::sdk::File::HLS_ATTRIBUTES) {
    LOGE("Incorrect file type: type = %d", static_cast<int>(file.type()));
    return false;
  }

  if (file.version() != video_widevine_client::sdk::File::VERSION_1) {
    LOGE("Incorrect file version: version = %d",
         static_cast<int>(file.version()));
    return false;
  }

  if (!file.has_hls_attributes()) {
    LOGE("HLS attributes not present");
    return false;
  }

  HlsAttributes attributes = file.hls_attributes();

  switch (attributes.method()) {
    case HlsAttributes_Method_AES_128:
      *method = kHlsMethodAes128;
      break;
    case HlsAttributes_Method_SAMPLE_AES:
      *method = kHlsMethodSampleAes;
      break;
    default:
      LOGW("Unrecognized HLS method: %d",
           static_cast<int>(attributes.method()));
      *method = kHlsMethodNone;
      break;
  }
  media_segment_iv->assign(attributes.media_segment_iv().begin(),
                           attributes.media_segment_iv().end());
  return true;
}

bool DeviceFiles::DeleteHlsAttributes(const std::string& key_set_id) {
  RETURN_FALSE_IF_UNINITIALIZED();
  return RemoveFile(key_set_id + kHlsAttributesFileNameExt);
}

bool DeviceFiles::StoreUsageTableInfo(
    const CdmUsageTableHeader& usage_table_header,
    const std::vector<CdmUsageEntryInfo>& usage_entry_info) {
  RETURN_FALSE_IF_UNINITIALIZED();

  // Fill in file information
  video_widevine_client::sdk::File file;

  file.set_type(video_widevine_client::sdk::File::USAGE_TABLE_INFO);
  file.set_version(video_widevine_client::sdk::File::VERSION_1);

  UsageTableInfo* usage_table_info = file.mutable_usage_table_info();
  usage_table_info->set_usage_table_header(usage_table_header);
  for (size_t i = 0; i < usage_entry_info.size(); ++i) {
    UsageTableInfo_UsageEntryInfo* info =
        usage_table_info->add_usage_entry_info();
    info->set_key_set_id(usage_entry_info[i].key_set_id);
    switch (usage_entry_info[i].storage_type) {
      case kStorageLicense:
        info->set_storage(
            UsageTableInfo_UsageEntryInfo_UsageEntryStorage_LICENSE);
        info->set_last_use_time(usage_entry_info[i].last_use_time);
        info->set_offline_license_expiry_time(
            usage_entry_info[i].offline_license_expiry_time);
        break;
      case kStorageUsageInfo:
        info->set_storage(
            UsageTableInfo_UsageEntryInfo_UsageEntryStorage_USAGE_INFO);
        info->set_usage_info_file_name(
            usage_entry_info[i].usage_info_file_name);
        info->set_last_use_time(usage_entry_info[i].last_use_time);
        break;
      case kStorageTypeUnknown:
      default:
        info->set_storage(
            UsageTableInfo_UsageEntryInfo_UsageEntryStorage_UNKNOWN);
        break;
    }
  }
  usage_table_info->set_use_lru(true);

  std::string serialized_file;
  file.SerializeToString(&serialized_file);

  return StoreFileWithHash(GetUsageTableFileName(), serialized_file) ==
         kNoError;
}

bool DeviceFiles::RetrieveUsageTableInfo(
    CdmUsageTableHeader* usage_table_header,
    std::vector<CdmUsageEntryInfo>* usage_entry_info, bool* lru_upgrade) {
  RETURN_FALSE_IF_UNINITIALIZED();
  RETURN_FALSE_IF_NULL(usage_table_header);
  RETURN_FALSE_IF_NULL(usage_entry_info);
  RETURN_FALSE_IF_NULL(lru_upgrade);

  video_widevine_client::sdk::File file;
  if (RetrieveHashedFile(GetUsageTableFileName(), &file) != kNoError) {
    LOGE("Unable to retrieve usage table file");
    return false;
  }

  if (file.type() != video_widevine_client::sdk::File::USAGE_TABLE_INFO) {
    LOGE("Incorrect file type: type = %d, expected_type = %d",
         static_cast<int>(file.type()),
         static_cast<int>(video_widevine_client::sdk::File::USAGE_TABLE_INFO));
    return false;
  }

  if (file.version() != video_widevine_client::sdk::File::VERSION_1) {
    LOGE("Incorrect file version: version = %d, expected_version = %d",
         static_cast<int>(file.version()),
         static_cast<int>(video_widevine_client::sdk::File::VERSION_1));
    return false;
  }

  if (!file.has_usage_table_info()) {
    LOGE("Usage table info not present in file");
    return false;
  }

  const UsageTableInfo& usage_table_info = file.usage_table_info();

  *lru_upgrade = !usage_table_info.use_lru();

  *usage_table_header = usage_table_info.usage_table_header();
  usage_entry_info->resize(usage_table_info.usage_entry_info_size());
  for (int i = 0; i < usage_table_info.usage_entry_info_size(); ++i) {
    const UsageTableInfo_UsageEntryInfo& info =
        usage_table_info.usage_entry_info(i);
    (*usage_entry_info)[i].key_set_id = info.key_set_id();
    switch (info.storage()) {
      case UsageTableInfo_UsageEntryInfo_UsageEntryStorage_LICENSE:
        (*usage_entry_info)[i].storage_type = kStorageLicense;
        (*usage_entry_info)[i].last_use_time = info.last_use_time();
        (*usage_entry_info)[i].offline_license_expiry_time =
            info.offline_license_expiry_time();
        break;
      case UsageTableInfo_UsageEntryInfo_UsageEntryStorage_USAGE_INFO:
        (*usage_entry_info)[i].storage_type = kStorageUsageInfo;
        (*usage_entry_info)[i].usage_info_file_name =
            info.usage_info_file_name();
        (*usage_entry_info)[i].last_use_time = info.last_use_time();
        break;
      case UsageTableInfo_UsageEntryInfo_UsageEntryStorage_UNKNOWN:
      default:
        (*usage_entry_info)[i].storage_type = kStorageTypeUnknown;
        break;
    }
  }

  return true;
}

bool DeviceFiles::DeleteUsageTableInfo() {
  RETURN_FALSE_IF_UNINITIALIZED();
  return RemoveFile(GetUsageTableFileName());
}

bool DeviceFiles::HasCertificate(CertificateType certificate_type) {
  RETURN_FALSE_IF_UNINITIALIZED();

  std::string certificate_file_name;
  if (!GetCertificateFileName(certificate_type, &certificate_file_name))
    return false;

  return FileExists(certificate_file_name);
}

DeviceFiles::ResponseType DeviceFiles::StoreFileWithHash(
    const std::string& name, const std::string& serialized_file) {
  std::string hash = Sha256Hash(serialized_file);

  // Fill in hashed file data
  HashedFile hash_file;
  hash_file.set_file(serialized_file);
  hash_file.set_hash(hash);

  std::string serialized_hash_file;
  hash_file.SerializeToString(&serialized_hash_file);

  return StoreFileRaw(name, serialized_hash_file);
}

DeviceFiles::ResponseType DeviceFiles::StoreFileRaw(
    const std::string& name, const std::string& serialized_file) {
  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level_, &path)) {
    LOGE("Unable to get base path");
    return kBasePathUnavailable;
  }

  path += name;

  auto file =
      file_system_->Open(path, FileSystem::kCreate | FileSystem::kTruncate);
  if (!file) {
    LOGE("Failed to open file: path = %s", path.c_str());
    return kFileOpenFailed;
  }

  const ssize_t bytes_written =
      file->Write(serialized_file.data(), serialized_file.size());

  if (bytes_written < 0) {
    LOGE("Failed to write to file: path = %s", path.c_str());
    return kFileWriteError;
  }
  if (bytes_written != static_cast<ssize_t>(serialized_file.size())) {
    LOGE(
        "Failed to fully write to file: path = %s, "
        "bytes_written = %zd, bytes_attempted = %zu",
        path.c_str(), bytes_written, serialized_file.size());
    return kFileWriteError;
  }

  LOGV("Successfully stored raw file: path = %s, size = %zu", path.c_str(),
       serialized_file.size());
  return kNoError;
}

DeviceFiles::ResponseType DeviceFiles::RetrieveHashedFile(
    const std::string& name,
    video_widevine_client::sdk::File* deserialized_file) {
  std::string serialized_file;

  if (deserialized_file == nullptr) {
    LOGE("File handle parameter |deserialized_file| not provided");
    return kParameterNull;
  }

  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level_, &path)) {
    LOGE("Unable to get base path");
    return kBasePathUnavailable;
  }

  path += name;

  if (!file_system_->Exists(path)) {
    LOGW("File does not exist: path = %s", path.c_str());
    return kFileNotFound;
  }

  const ssize_t file_size = file_system_->FileSize(path);
  if (file_size <= 0) {
    LOGE("File size is invalid: %s", path.c_str());
    // Remove the corrupted file so the caller will not get the same error
    // when trying to access the file repeatedly, causing the system to stall.
    file_system_->Remove(path);
    return kInvalidFileSize;
  }

  auto file = file_system_->Open(path, FileSystem::kReadOnly);
  if (!file) {
    return kFileOpenFailed;
  }

  std::string serialized_hash_file;
  serialized_hash_file.resize(file_size);
  const ssize_t bytes_read =
      file->Read(&serialized_hash_file[0], serialized_hash_file.size());

  if (bytes_read != file_size) {
    if (bytes_read < 0) {
      LOGE("Failed to read from file: path = %s", path.c_str());
    } else {
      LOGE(
          "Failed to fully read from file: "
          "path = %s, bytes_read = %zd, bytes_attempted = %zd",
          path.c_str(), bytes_read, file_size);
    }
    // Remove the corrupted file so the caller will not get the same error
    // when trying to access the file repeatedly, causing the system to stall.
    file_system_->Remove(path);
    return kFileReadError;
  }

  LOGV("Successfully read file: path = %s, size = %zu", path.c_str(),
       serialized_hash_file.size());

  HashedFile hash_file;
  if (!hash_file.ParseFromString(serialized_hash_file)) {
    LOGE("Unable to parse hash file");
    // Remove the corrupted file so the caller will not get the same error
    // when trying to access the file repeatedly, causing the system to stall.
    file_system_->Remove(path);
    return kFileParseError1;
  }

  std::string hash = Sha256Hash(hash_file.file());
  if (hash != hash_file.hash()) {
    LOGE("File hash mismatch: path = %s", path.c_str());
    // Remove the corrupted file so the caller will not get the same error
    // when trying to access the file repeatedly, causing the system to stall.
    file_system_->Remove(path);
    return kFileHashMismatch;
  }

  if (!deserialized_file->ParseFromString(hash_file.file())) {
    LOGE("Unable to parse hashed file");
    // Remove the corrupted file so the caller will not get the same error
    // when trying to access the file repeatedly, causing the system to stall.
    file_system_->Remove(path);
    return kFileParseError2;
  }
  return kNoError;
}

bool DeviceFiles::FileExists(const std::string& name) {
  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level_, &path)) {
    LOGE("Unable to get base path");
    return false;
  }
  path += name;

  return file_system_->Exists(path);
}

bool DeviceFiles::ListFiles(std::vector<std::string>* names) {
  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level_, &path)) {
    LOGE("Unable to get base path");
    return false;
  }
  return file_system_->List(path, names);
}

bool DeviceFiles::RemoveFile(const std::string& name) {
  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level_, &path)) {
    LOGE("Unable to get base path");
    return false;
  }
  path += name;

  return file_system_->Remove(path);
}

ssize_t DeviceFiles::GetFileSize(const std::string& name) {
  std::string path;
  if (!Properties::GetDeviceFilesBasePath(security_level_, &path)) {
    LOGE("Unable to get base path");
    return -1;
  }
  path += name;

  return file_system_->FileSize(path);
}

bool DeviceFiles::GetCertificateFileName(CertificateType certificate_type,
                                         std::string* file_name) {
  RETURN_FALSE_IF_NULL(file_name);
  switch (certificate_type) {
    case kCertificateDefault:
      *file_name = kCertificateFileName;
      return true;
    case kCertificateLegacy:
      *file_name = kLegacyCertificateFileName;
      return true;
    case kCertificateAtsc:
      *file_name = kAtscCertificateFileName;
      return true;
    default:
      return false;
  }
}

std::string DeviceFiles::GetUsageTableFileName() { return kUsageTableFileName; }

std::string DeviceFiles::GetHlsAttributesFileNameExtension() {
  return kHlsAttributesFileNameExt;
}

std::string DeviceFiles::GetLicenseFileNameExtension() {
  return kLicenseFileNameExt;
}

std::string DeviceFiles::GetUsageInfoFileName(const std::string& app_id) {
  std::string hash;
  if (app_id != "") {
    hash = GetFileNameSafeHash(app_id);
  }
  return kUsageInfoFileNamePrefix + hash + kUsageInfoFileNameExt;
}

std::string DeviceFiles::GetFileNameSafeHash(const std::string& input) {
  return wvcdm::Base64SafeEncode(Md5Hash(input));
}

}  // namespace wvcdm