不要怂,就是干,撸起袖子干!

query-interface.js 5.05 KB
'use strict';

const DataTypes = require('../../data-types');
const QueryTypes = require('../../query-types');
const _ = require('lodash');


/**
 Returns an object that handles Postgres special needs to do certain queries.

 @class QueryInterface
 @static
 @private
 */

/**
   * Ensure enum and their values.
   *
   * @param {QueryInterface} qi
   * @param {string} tableName  Name of table to create
   * @param {object} attributes Object representing a list of normalized table attributes
   * @param {object} [options]
   * @param {Model}  [model]
   *
   * @returns {Promise}
   * @private
   */
async function ensureEnums(qi, tableName, attributes, options, model) {
  const keys = Object.keys(attributes);
  const keyLen = keys.length;

  let sql = '';
  let promises = [];
  let i = 0;

  for (i = 0; i < keyLen; i++) {
    const attribute = attributes[keys[i]];
    const type = attribute.type;

    if (
      type instanceof DataTypes.ENUM ||
      type instanceof DataTypes.ARRAY && type.type instanceof DataTypes.ENUM //ARRAY sub type is ENUM
    ) {
      sql = qi.QueryGenerator.pgListEnums(tableName, attribute.field || keys[i], options);
      promises.push(qi.sequelize.query(
        sql,
        Object.assign({}, options, { plain: true, raw: true, type: QueryTypes.SELECT })
      ));
    }
  }

  const results = await Promise.all(promises);
  promises = [];
  let enumIdx = 0;

  // This little function allows us to re-use the same code that prepends or appends new value to enum array
  const addEnumValue = (field, value, relativeValue, position = 'before', spliceStart = promises.length) => {
    const valueOptions = _.clone(options);
    valueOptions.before = null;
    valueOptions.after = null;

    switch (position) {
      case 'after':
        valueOptions.after = relativeValue;
        break;
      case 'before':
      default:
        valueOptions.before = relativeValue;
        break;
    }

    promises.splice(spliceStart, 0, () => {
      return qi.sequelize.query(qi.QueryGenerator.pgEnumAdd(
        tableName, field, value, valueOptions
      ), valueOptions);
    });
  };

  for (i = 0; i < keyLen; i++) {
    const attribute = attributes[keys[i]];
    const type = attribute.type;
    const enumType = type.type || type;
    const field = attribute.field || keys[i];

    if (
      type instanceof DataTypes.ENUM ||
      type instanceof DataTypes.ARRAY && enumType instanceof DataTypes.ENUM //ARRAY sub type is ENUM
    ) {
      // If the enum type doesn't exist then create it
      if (!results[enumIdx]) {
        promises.push(() => {
          return qi.sequelize.query(qi.QueryGenerator.pgEnum(tableName, field, enumType, options), Object.assign({}, options, { raw: true }));
        });
      } else if (!!results[enumIdx] && !!model) {
        const enumVals = qi.QueryGenerator.fromArray(results[enumIdx].enum_value);
        const vals = enumType.values;

        // Going through already existing values allows us to make queries that depend on those values
        // We will prepend all new values between the old ones, but keep in mind - we can't change order of already existing values
        // Then we append the rest of new values AFTER the latest already existing value
        // E.g.: [1,2] -> [0,2,1] ==> [1,0,2]
        // E.g.: [1,2,3] -> [2,1,3,4] ==> [1,2,3,4]
        // E.g.: [1] -> [0,2,3] ==> [1,0,2,3]
        let lastOldEnumValue;
        let rightestPosition = -1;
        for (let oldIndex = 0; oldIndex < enumVals.length; oldIndex++) {
          const enumVal = enumVals[oldIndex];
          const newIdx = vals.indexOf(enumVal);
          lastOldEnumValue = enumVal;

          if (newIdx === -1) {
            continue;
          }

          const newValuesBefore = vals.slice(0, newIdx);
          const promisesLength = promises.length;
          // we go in reverse order so we could stop when we meet old value
          for (let reverseIdx = newValuesBefore.length - 1; reverseIdx >= 0; reverseIdx--) {
            if (~enumVals.indexOf(newValuesBefore[reverseIdx])) {
              break;
            }

            addEnumValue(field, newValuesBefore[reverseIdx], lastOldEnumValue, 'before', promisesLength);
          }

          // we detect the most 'right' position of old value in new enum array so we can append new values to it
          if (newIdx > rightestPosition) {
            rightestPosition = newIdx;
          }
        }

        if (lastOldEnumValue && rightestPosition < vals.length - 1) {
          const remainingEnumValues = vals.slice(rightestPosition + 1);
          for (let reverseIdx = remainingEnumValues.length - 1; reverseIdx >= 0; reverseIdx--) {
            addEnumValue(field, remainingEnumValues[reverseIdx], lastOldEnumValue, 'after');
          }
        }

        enumIdx++;
      }
    }
  }

  const result = await promises
    .reduce(async (promise, asyncFunction) => await asyncFunction(await promise), Promise.resolve());

  // If ENUM processed, then refresh OIDs
  if (promises.length) {
    await qi.sequelize.dialect.connectionManager._refreshDynamicOIDs();
  }
  return result;
}


exports.ensureEnums = ensureEnums;