C++ StringPiece::subpiece方法代码示例

const std::vector<McrouterRouteHandlePtr>*
RouteHandleMap::getTargetsForKeyFast(folly::StringPiece prefix,
                                     folly::StringPiece key) const {
  // empty prefix => route to default route
  if (prefix.empty()) {
    return &getBySingleRoute(defaultRoute_, key);
  }

  // route to all routes
  if (prefix == "/*/*/") {
    return &allRoutes_->getTargetsForKey(key);
  }

  auto starPos = prefix.find("*");
  if (starPos == std::string::npos) {
    // no stars at all
    return &getBySingleRoute(prefix, key);
  }

  if (prefix.endsWith("/*/") && starPos == prefix.size() - 2) {
    // route to all clusters of some region (/region/*/)
    auto region = prefix.subpiece(1, prefix.size() - 4);
    auto it = byRegion_.find(region);
    if (it == byRegion_.end()) {
      return &emptyV_;
    }
    return &it->second->getTargetsForKey(key);
  }

  // no other types supported
  return nullptr;
}

const std::vector<McrouterRouteHandlePtr>*
RouteHandleMap::getTargetsForKeyFast(folly::StringPiece prefix,
                                     folly::StringPiece key) const {
  const std::vector<McrouterRouteHandlePtr>* result = nullptr;
  if (prefix.empty()) {
    // empty prefix => route to default route
    result = &defaultRouteMap_->getTargetsForKey(key);
  } else if (prefix == "/*/*/") {
    // route to all routes
    result = &allRoutes_->getTargetsForKey(key);
  } else {
    auto starPos = prefix.find("*");
    if (starPos == std::string::npos) {
      // no stars at all
      auto it = byRoute_.find(prefix);
      result = it == byRoute_.end()
        ? &emptyV_
        : &it->second->getTargetsForKey(key);
    } else if (prefix.endsWith("/*/") && starPos == prefix.size() - 2) {
      // route to all clusters of some region (/region/*/)
      auto region = prefix.subpiece(1, prefix.size() - 4);
      auto it = byRegion_.find(region);
      result = it == byRegion_.end()
        ? &emptyV_
        : &it->second->getTargetsForKey(key);
    }
  }
  if (sendInvalidRouteToDefault_ && result != nullptr && result->empty()) {
    return &defaultRouteMap_->getTargetsForKey(key);
  }
  return result;
}

std::shared_ptr<AccessPoint>
AccessPoint::create(folly::StringPiece apString,
                    mc_protocol_t defaultProtocol,
                    bool defaultUseSsl,
                    uint16_t portOverride) {
    if (apString.empty()) {
        return nullptr;
    }

    folly::StringPiece host;
    if (apString[0] == '[') {
        // IPv6
        auto closing = apString.find(']');
        if (closing == std::string::npos) {
            return nullptr;
        }
        host = apString.subpiece(1, closing - 1);
        apString.advance(closing + 1);
    } else {
        // IPv4 or hostname
        auto colon = apString.find(':');
        if (colon == std::string::npos) {
            host = apString;
            apString = "";
        } else {
            host = apString.subpiece(0, colon);
            apString.advance(colon);
        }
    }

    if (host.empty()) {
        return nullptr;
    }

    try {
        folly::StringPiece port, protocol, encr;
        parseParts(apString, port, protocol, encr);

        return std::make_shared<AccessPoint>(
                   host,
                   portOverride != 0 ? portOverride : folly::to<uint16_t>(port),
                   protocol.empty() ? defaultProtocol : parseProtocol(protocol),
                   encr.empty() ? defaultUseSsl : parseSsl(encr));
    } catch (const std::exception&) {
        return nullptr;
    }
}

/*
 * Writes a file path to a file while folding any consecutive forward slashes.
 */
void write_path(int fd, folly::StringPiece path) {
  while (!path.empty()) {
    auto const pos = path.find('/');
    if (pos == std::string::npos) {
      folly::writeNoInt(fd, path.data(), path.size());
      break;
    }

    auto const left = path.subpiece(0, pos + 1);
    folly::writeNoInt(fd, left.data(), left.size());

    auto right = path.subpiece(pos);
    while (!right.empty() && right[0] == '/') {
      right = right.subpiece(1);
    }

    path = right;
  }
}

// Helper function to check if URL has valid scheme.
// http_parser only support full form scheme with double slash,
// and the scheme must be all alphabetic charecter.
static bool validateScheme(folly::StringPiece url) {
  auto schemeEnd = url.find("://");
  if (schemeEnd == std::string::npos || schemeEnd == 0) {
    return false;
  }

  auto scheme = url.subpiece(0, schemeEnd);
  return std::all_of(scheme.begin(), scheme.end(), [](auto _) {
      return std::isalpha(_);
  });
}

void DebugProtocolWriter::writeSP(folly::StringPiece str) {
  static constexpr size_t kStringLimit = 256;
  static constexpr size_t kStringPrefixSize = 128;

  std::string toShow = str.str();
  if (toShow.length() > kStringLimit) {
    toShow = str.subpiece(0, kStringPrefixSize).str();
    folly::toAppend("[...](", str.size(), ")", &toShow);
  }

  writeItem("\"{}\"", folly::cEscape<std::string>(toShow));
}

bool getShardId(folly::StringPiece key, folly::StringPiece& shardId) {
  size_t colon = qfind(key, ':');
  if (colon == std::string::npos) {
    return false;
  }
  key.advance(colon + 1);
  colon = qfind(key, ':');
  if (colon == std::string::npos) {
    return false;
  }
  if (colon <= 0 || !isdigit(key[colon - 1])) {
    return false;
  }
  shardId = key.subpiece(0, colon);
  return true;
}

int32_t CarbonRouterInstanceBase::getStatsEnabledPoolIndex(
    const folly::StringPiece poolName) const {
  if (statsEnabledPools_.size() == 0) {
    return -1;
  }

  int longestPrefixMatchIndex = -1;
  // Do sequential search for longest matching name. Since this is done
  // only once during the initialization and the size of the array is
  // expected to be small, linear search should be OK.
  for (size_t i = 0; i < statsEnabledPools_.size(); i++) {
    if (poolName.subpiece(0, statsEnabledPools_[i].length())
            .compare(statsEnabledPools_[i]) == 0) {
      if ((longestPrefixMatchIndex == -1) ||
          (statsEnabledPools_[longestPrefixMatchIndex].length() <
           statsEnabledPools_[i].length())) {
        longestPrefixMatchIndex = i;
      }
    }
  }

  return longestPrefixMatchIndex;
}

std::shared_ptr<AccessPoint> AccessPoint::create(
    folly::StringPiece apString,
    mc_protocol_t defaultProtocol,
    SecurityMech defaultMech,
    uint16_t portOverride,
    bool defaultCompressed) {
  if (apString.empty()) {
    return nullptr;
  }

  folly::StringPiece host;
  bool unixDomainSocket = false;
  if (apString[0] == '[') {
    // IPv6
    auto closing = apString.find(']');
    if (closing == std::string::npos) {
      return nullptr;
    }
    host = apString.subpiece(1, closing - 1);
    apString.advance(closing + 1);
  } else {
    // IPv4 or hostname or UNIX domain socket
    if (apString.subpiece(0, 5) == "unix:") { // Unix domain socket
      unixDomainSocket = true;
      apString.advance(5);
    }
    auto colon = apString.find(':');
    if (colon == std::string::npos) {
      host = apString;
      apString = "";
    } else {
      host = apString.subpiece(0, colon);
      apString.advance(colon);
    }
  }

  if (host.empty()) {
    return nullptr;
  }

  try {
    folly::StringPiece port, protocol, encr, comp;
    if (unixDomainSocket) {
      port = "0";
      parseParts(apString, protocol, encr, comp);
      // Unix Domain Sockets with SSL is not supported.
      if (!encr.empty() && parseSecurityMech(encr) != SecurityMech::NONE) {
        return nullptr;
      }
    } else {
      parseParts(apString, port, protocol, encr, comp);
    }

    return std::make_shared<AccessPoint>(
        host,
        portOverride != 0 ? portOverride : folly::to<uint16_t>(port),
        protocol.empty() ? defaultProtocol : parseProtocol(protocol),
        encr.empty() ? defaultMech : parseSecurityMech(encr),
        comp.empty() ? defaultCompressed : parseCompressed(comp),
        unixDomainSocket);
  } catch (const std::exception&) {
    return nullptr;
  }
}

std::string shorten(folly::StringPiece s, size_t maxLength) {
  if (s.size() <= maxLength || s.size() <= 3) {
    return s.str();
  }
  return s.subpiece(0, maxLength - 3).str() + "...";
}