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'use strict';
const clone = require('./clone');const MongooseError = require('../error/index');
function processConnectionOptions(uri, options) {  const opts = options ? options : {};  const readPreference = opts.readPreference    ? opts.readPreference    : getUriReadPreference(uri);
  const resolvedOpts = (readPreference && readPreference !== 'primary' && readPreference !== 'primaryPreferred')    ? resolveOptsConflicts(readPreference, opts)    : opts;
  return clone(resolvedOpts);}
function resolveOptsConflicts(pref, opts) {  // don't silently override user-provided indexing options  if (setsIndexOptions(opts) && setsSecondaryRead(pref)) {    throwReadPreferenceError();  }
  // if user has not explicitly set any auto-indexing options,  // we can silently default them all to false  else {    return defaultIndexOptsToFalse(opts);  }}
function setsIndexOptions(opts) {  const configIdx = opts.config && opts.config.autoIndex;  const { autoCreate, autoIndex } = opts;  return !!(configIdx || autoCreate || autoIndex);}
function setsSecondaryRead(prefString) {  return !!(prefString === 'secondary' || prefString === 'secondaryPreferred');}
function getUriReadPreference(connectionString) {  const exp = /(?:&|\?)readPreference=(\w+)(?:&|$)/;  const match = exp.exec(connectionString);  return match ? match[1] : null;}
function defaultIndexOptsToFalse(opts) {  opts.config = { autoIndex: false };  opts.autoCreate = false;  opts.autoIndex = false;  return opts;}
function throwReadPreferenceError() {  throw new MongooseError(    'MongoDB prohibits index creation on connections that read from ' +            'non-primary replicas.  Connections that set "readPreference" to "secondary" or ' +            '"secondaryPreferred" may not opt-in to the following connection options: ' +            'autoCreate, autoIndex'  );}
module.exports = processConnectionOptions;