nearby/presence/np_cpp_ffi/sample/main.cc

// Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "nearby_protocol.h"

#include <bitset>
#include <iostream>

#include "absl/strings/escaping.h"

static void SamplePanicHandler(nearby_protocol::PanicReason reason);

void HandleAdvertisementResult(nearby_protocol::DeserializeAdvertisementResult);

void HandleV0Adv(nearby_protocol::DeserializedV0Advertisement);
void HandleLegibleV0Adv(nearby_protocol::LegibleDeserializedV0Advertisement);
void HandleV0IdentityKind(nearby_protocol::DeserializedV0IdentityKind);
void HandleDataElement(nearby_protocol::V0DataElement);

void HandleV1Adv(nearby_protocol::DeserializedV1Advertisement);
void HandleV1Section(nearby_protocol::DeserializedV1Section);
void HandleV1DataElement(nearby_protocol::V1DataElement);

int main() {
  auto result =
      nearby_protocol::GlobalConfig::SetPanicHandler(SamplePanicHandler);
  if (result) {
    std::cout << "Successfully registered panic handler\n";
  } else {
    std::cout << "Failed register panic handler\n";
    return -1;
  }
  nearby_protocol::GlobalConfig::SetNumShards(4);

  std::cout << "\n========= Example V0 Adv ==========\n";
  std::cout << "Hex bytes: 00031503260046\n\n";

  // Create an empty credential slab and verify that it is successful
  auto cred_slab_result = nearby_protocol::CredentialSlab::TryCreate();
  if (!cred_slab_result.ok()) {
    std::cout << cred_slab_result.status().ToString();
    return -1;
  }

  // Create an empty credential book from the empty slab, and verify success.
  auto cred_book_result = nearby_protocol::CredentialBook::TryCreateFromSlab(cred_slab_result.value());
  if (!cred_book_result.ok()) {
    std::cout << cred_book_result.status().ToString();
    return -1;
  }

  auto v0_byte_string = "00"      // Adv Header
                        "03"      // Public DE header
                        "1503"    // Length 1 Tx Power DE with value 3
                        "260046"; // Length 2 Actions

  auto v0_bytes = absl::HexStringToBytes(v0_byte_string);
  auto v0_buffer = nearby_protocol::ByteBuffer<255>::CopyFrom(v0_bytes);
  nearby_protocol::RawAdvertisementPayload v0_payload(v0_buffer.value());

  // Try to deserialize a V0 payload
  auto deserialize_v0_result =
      nearby_protocol::Deserializer::DeserializeAdvertisement(
          v0_payload, cred_book_result.value());
  HandleAdvertisementResult(std::move(deserialize_v0_result));

  std::cout << "\n========= Example V1 Adv ==========\n";
  std::cout << "Hex bytes: 20040326004603031505\n\n";

  auto v1_byte_string = "20"     // V1 Advertisement header
                        "04"     // Section Header
                        "03"     // Public Identity DE header
                        "260046";// Length 2 Actions DE

  auto v1_bytes = absl::HexStringToBytes(v1_byte_string);
  auto v1_buffer = nearby_protocol::ByteBuffer<255>::CopyFrom(v1_bytes);
  nearby_protocol::RawAdvertisementPayload v1_payload(v1_buffer.value());

  // Try to deserialize a V1 payload
  auto deserialize_v1_result =
      nearby_protocol::Deserializer::DeserializeAdvertisement(
          v1_payload, cred_book_result.value());
  HandleAdvertisementResult(std::move(deserialize_v1_result));

  std::cout << "\n========= User input sample ==========\n\n";
  while (true) {
    std::string user_input;
    std::cout << "Enter the hex of the advertisement you would like to parse "
                 "(see above examples): ";
    std::cin >> user_input;
    auto bytes = absl::HexStringToBytes(user_input);
    auto buffer = nearby_protocol::ByteBuffer<255>::CopyFrom(bytes);
    if (!buffer.ok()) {
      std::cout << "Too many bytes provided, must fit into a max length 255 "
                   "byte BLE advertisement\n";
      continue;
    }
    nearby_protocol::RawAdvertisementPayload user_input_payload(buffer.value());

    // Try to deserialize user input
    auto user_input_result =
        nearby_protocol::Deserializer::DeserializeAdvertisement(
            user_input_payload, cred_book_result.value());
    HandleAdvertisementResult(std::move(user_input_result));

    char choice;
    do {
      std::cout << "Do you want to continue? (Y/N) ";
      std::cin >> choice;
    } while (choice != 'Y' && choice != 'N' && choice != 'n' && choice != 'y');

    if (choice == 'N' || choice == 'n') {
      return 0;
    }
  }
}

static void SamplePanicHandler(nearby_protocol::PanicReason reason) {
  std::cout << "Panicking! Reason: ";
  switch (reason) {
  case nearby_protocol::PanicReason::EnumCastFailed: {
    std::cout << "EnumCastFailed \n";
    break;
  }
  case nearby_protocol::PanicReason::AssertFailed: {
    std::cout << "AssertFailed \n";
    break;
  }
  case nearby_protocol::PanicReason::InvalidActionBits: {
    std::cout << "InvalidActionBits \n";
    break;
  }
  }
  std::abort();
}

void HandleAdvertisementResult(
    nearby_protocol::DeserializeAdvertisementResult result) {
  switch (result.GetKind()) {
  case nearby_protocol::DeserializeAdvertisementResultKind::Error:
    std::cout << "Error in deserializing advertisement!\n";
    break;
  case nearby_protocol::DeserializeAdvertisementResultKind::V0:
    std::cout << "Successfully deserialized a V0 advertisement!\n";
    HandleV0Adv(result.IntoV0());
    break;
  case nearby_protocol::DeserializeAdvertisementResultKind::V1:
    std::cout << "Successfully deserialized a V1 advertisement\n";
    HandleV1Adv(result.IntoV1());
    break;
  }
}

void HandleV0Adv(nearby_protocol::DeserializedV0Advertisement result) {
  switch (result.GetKind()) {
  case nearby_protocol::DeserializedV0AdvertisementKind::Legible:
    std::cout << "\tThe Advertisement is plaintext \n";
    HandleLegibleV0Adv(result.IntoLegible());
    break;
  case nearby_protocol::DeserializedV0AdvertisementKind::NoMatchingCredentials:
    std::cout << "\tNo matching credentials found for this adv\n";
    return;
  }
}

void HandleLegibleV0Adv(
    nearby_protocol::LegibleDeserializedV0Advertisement legible_adv) {
  HandleV0IdentityKind(legible_adv.GetIdentityKind());

  auto num_des = legible_adv.GetNumberOfDataElements();
  std::cout << "\t\tAdv contains " << unsigned(num_des) << " data elements \n";
  auto payload = legible_adv.IntoPayload();
  for (int i = 0; i < num_des; i++) {
    auto de_result = payload.TryGetDataElement(i);
    if (!de_result.ok()) {
      std::cout << "\t\tError getting DE at index: " << i << "\n";
      return;
    }
    std::cout << "\t\tSuccessfully retrieved De at index " << i << "\n";
    HandleDataElement(de_result.value());
  }
}

void HandleV0IdentityKind(nearby_protocol::DeserializedV0IdentityKind identity) {
  switch (identity) {
  case np_ffi::internal::DeserializedV0IdentityKind::Plaintext: {
    std::cout << "\t\tIdentity is Plaintext\n";
    break;
  }
  case np_ffi::internal::DeserializedV0IdentityKind::Decrypted: {
    std::cout << "\t\tIdentity is Encrypted\n";
    break;
  }
  }
}

void HandleDataElement(nearby_protocol::V0DataElement de) {
  switch (de.GetKind()) {
  case nearby_protocol::V0DataElementKind::TxPower: {
    std::cout << "\t\t\tDE Type is TxPower\n";
    auto tx_power = de.AsTxPower();
    std::cout << "\t\t\tpower: " << int(tx_power.tx_power) << "\n";
    return;
  }
  case nearby_protocol::V0DataElementKind::Actions: {
    std::cout << "\t\t\tDE Type is Actions\n";
    auto actions = de.AsActions();
    std::cout << "\t\t\tactions: " << std::bitset<32>(actions.GetAsU32())
              << "\n";
    return;
  }
  }
}

void HandleV1Adv(nearby_protocol::DeserializedV1Advertisement adv) {
  auto legible_sections = adv.GetNumLegibleSections();
  std::cout << "\tAdv has " << unsigned(legible_sections)
            << " legible sections \n";

  auto encrypted_sections = adv.GetNumUndecryptableSections();
  std::cout << "\tAdv has " << unsigned(encrypted_sections)
            << " undecryptable sections\n";

  for (auto i = 0; i < legible_sections; i++) {
    auto section_result = adv.TryGetSection(i);
    if (!section_result.ok()) {
      std::cout << "\tError getting Section at index: " << i << "\n";
      return;
    }
    std::cout << "\tSuccessfully retrieved section at index " << i << "\n";
    HandleV1Section(section_result.value());
  }
}

void HandleV1Section(nearby_protocol::DeserializedV1Section section) {
  switch (section.GetIdentityKind()) {
  case np_ffi::internal::DeserializedV1IdentityKind::Plaintext: {
    std::cout << "\t\tIdentity is Plaintext\n";
    break;
  }
  case np_ffi::internal::DeserializedV1IdentityKind::Decrypted: {
    std::cout << "\t\tIdentity is Encrypted\n";
    break;
  }
  }

  auto num_des = section.NumberOfDataElements();
  std::cout << "\t\tSection has " << unsigned(num_des) << " data elements \n";
  for (auto i = 0; i < num_des; i++) {
    auto de_result = section.TryGetDataElement(i);
    if (!de_result.ok()) {
      std::cout << "\t\tError getting de at index: " << i << "\n";
      return;
    }
    std::cout << "\t\tSuccessfully retrieved data element at index " << i
              << "\n";
    HandleV1DataElement(de_result.value());
  }
}

void HandleV1DataElement(nearby_protocol::V1DataElement de) {
  std::cout << "\t\t\tData Element type code: "
            << unsigned(de.GetDataElementTypeCode()) << "\n";
  std::cout << "\t\t\tPayload bytes as hex: "
            << absl::BytesToHexString(de.GetPayload().ToString()) << "\n";
}