////////////////////////////////////////////////////////////////////////////////
// Copyright 2019 Google LLC.
//
// This software is licensed under the terms defined in the Widevine Master
// License Agreement. For a copy of this agreement, please contact
// widevine-licensing@google.com.
////////////////////////////////////////////////////////////////////////////////
//
// Description:
//   Shared private key utilities between RSA and EC.

#ifndef COMMON_PRIVATE_KEY_UTIL_H_
#define COMMON_PRIVATE_KEY_UTIL_H_

#include <string>

#include "glog/logging.h"
#include "openssl/bio.h"

namespace widevine {
namespace private_key_util {

template <class Key>
bool SerializeKey(const Key* key, int (*serialization_func)(BIO*, Key*),
                  std::string* serialized_key) {
  if (key == nullptr) {
    LOG(ERROR) << "Key is nullptr.";
    return false;
  }
  if (serialized_key == nullptr) {
    LOG(ERROR) << "Pointer to hold serialized key is nullptr.";
    return false;
  }
  BIO* bio = BIO_new(BIO_s_mem());
  if (bio == nullptr) {
    LOG(ERROR) << "BIO_new returned nullptr";
    return false;
  }
  bool success = false;
  if (serialization_func(bio, const_cast<Key*>(key)) != 0) {
    int serialized_size = BIO_pending(bio);
    serialized_key->assign(serialized_size, 0);
    if (BIO_read(bio, &(*serialized_key)[0], serialized_size) ==
        serialized_size) {
      success = true;
    } else {
      LOG(ERROR) << "BIO_read failure";
    }
  } else {
    LOG(ERROR) << "Key serialization failure";
  }
  BIO_free(bio);
  return success;
}

template <class Key>
bool DeserializeKey(const std::string& serialized_key,
                    Key* (*deserialization_func)(BIO*, Key**), Key** key) {
  if (serialized_key.empty()) {
    LOG(ERROR) << "Serialized key is empty.";
    return false;
  }
  if (key == nullptr) {
    LOG(ERROR) << "Pointer to hold new key is nullptr.";
    return false;
  }
  BIO* bio = BIO_new_mem_buf(const_cast<char*>(serialized_key.data()),
                             serialized_key.size());
  if (bio == nullptr) {
    LOG(ERROR) << "BIO_new_mem_buf returned nullptr";
    return false;
  }
  *key = deserialization_func(bio, nullptr);
  BIO_free(bio);
  if (*key == nullptr) {
    LOG(ERROR) << "Key deserialization failure";
  }
  return *key != nullptr;
}

}  // namespace private_key_util
}  // namespace widevine

#endif  // COMMON_PRIVATE_KEY_UTIL_H_