30-seconds-of-code/node_modules/relay-runtime/lib/RelayModernStore.js

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 *  strict-local
 * @format
 */
'use strict';

var _objectSpread2 = require("@babel/runtime/helpers/interopRequireDefault")(require("@babel/runtime/helpers/objectSpread"));

/**
 * @public
 *
 * An implementation of the `Store` interface defined in `RelayStoreTypes`.
 *
 * Note that a Store takes ownership of all records provided to it: other
 * objects may continue to hold a reference to such records but may not mutate
 * them. The static Relay core is architected to avoid mutating records that may have been
 * passed to a store: operations that mutate records will either create fresh
 * records or clone existing records and modify the clones. Record immutability
 * is also enforced in development mode by freezing all records passed to a store.
 */
var RelayModernStore =
/*#__PURE__*/
function () {
  function RelayModernStore(source) {
    var gcScheduler = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : require("fbjs/lib/resolveImmediate");
    var operationLoader = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;

    // Prevent mutation of a record from outside the store.
    if (process.env.NODE_ENV !== "production") {
      var storeIDs = source.getRecordIDs();

      for (var ii = 0; ii < storeIDs.length; ii++) {
        var record = source.get(storeIDs[ii]);

        if (record) {
          require("./RelayModernRecord").freeze(record);
        }
      }
    }

    this._gcScheduler = gcScheduler;
    this._hasScheduledGC = false;
    this._index = 0;
    this._operationLoader = operationLoader;
    this._recordSource = source;
    this._roots = new Map();
    this._subscriptions = new Set();
    this._updatedRecordIDs = {};
    this._gcHoldCounter = 0;
    this._shouldScheduleGC = false;
  }

  var _proto = RelayModernStore.prototype;

  _proto.getSource = function getSource() {
    return this._recordSource;
  };

  _proto.check = function check(selector) {
    return require("./DataChecker").check(this._recordSource, this._recordSource, selector, [], this._operationLoader);
  };

  _proto.retain = function retain(selector) {
    var _this = this;

    var index = this._index++;

    var dispose = function dispose() {
      _this._roots["delete"](index);

      _this._scheduleGC();
    };

    this._roots.set(index, selector);

    return {
      dispose: dispose
    };
  };

  _proto.lookup = function lookup(selector, owner) {
    var snapshot = require("./RelayReader").read(this._recordSource, selector, owner);

    if (process.env.NODE_ENV !== "production") {
      require("./deepFreeze")(snapshot);
    }

    return snapshot;
  };

  _proto.notify = function notify() {
    var _this2 = this;

    this._subscriptions.forEach(function (subscription) {
      _this2._updateSubscription(subscription);
    });

    this._updatedRecordIDs = {};
  };

  _proto.publish = function publish(source) {
    updateTargetFromSource(this._recordSource, source, this._updatedRecordIDs);
  };

  _proto.subscribe = function subscribe(snapshot, callback) {
    var _this3 = this;

    var subscription = {
      callback: callback,
      snapshot: snapshot
    };

    var dispose = function dispose() {
      _this3._subscriptions["delete"](subscription);
    };

    this._subscriptions.add(subscription);

    return {
      dispose: dispose
    };
  };

  _proto.holdGC = function holdGC() {
    var _this4 = this;

    this._gcHoldCounter++;

    var dispose = function dispose() {
      if (_this4._gcHoldCounter > 0) {
        _this4._gcHoldCounter--;

        if (_this4._gcHoldCounter === 0 && _this4._shouldScheduleGC) {
          _this4._scheduleGC();

          _this4._shouldScheduleGC = false;
        }
      }
    };

    return {
      dispose: dispose
    };
  };

  _proto.toJSON = function toJSON() {
    return 'RelayModernStore()';
  }; // Internal API


  _proto.__getUpdatedRecordIDs = function __getUpdatedRecordIDs() {
    return this._updatedRecordIDs;
  };

  _proto._updateSubscription = function _updateSubscription(subscription) {
    var callback = subscription.callback,
        snapshot = subscription.snapshot;

    if (!require("./hasOverlappingIDs")(snapshot, this._updatedRecordIDs)) {
      return;
    }

    var _RelayReader$read = require("./RelayReader").read(this._recordSource, snapshot, snapshot.owner),
        data = _RelayReader$read.data,
        seenRecords = _RelayReader$read.seenRecords;

    var nextData = require("./recycleNodesInto")(snapshot.data, data);

    var nextSnapshot = (0, _objectSpread2["default"])({}, snapshot, {
      data: nextData,
      seenRecords: seenRecords
    });

    if (process.env.NODE_ENV !== "production") {
      require("./deepFreeze")(nextSnapshot);
    }

    subscription.snapshot = nextSnapshot;

    if (nextSnapshot.data !== snapshot.data) {
      callback(nextSnapshot);
    }
  };

  _proto._scheduleGC = function _scheduleGC() {
    var _this5 = this;

    if (this._gcHoldCounter > 0) {
      this._shouldScheduleGC = true;
      return;
    }

    if (this._hasScheduledGC) {
      return;
    }

    this._hasScheduledGC = true;

    this._gcScheduler(function () {
      _this5.__gc();

      _this5._hasScheduledGC = false;
    });
  };

  _proto.__gc = function __gc() {
    var _this6 = this;

    var references = new Set(); // Mark all records that are traversable from a root

    this._roots.forEach(function (selector) {
      require("./RelayReferenceMarker").mark(_this6._recordSource, selector, references, _this6._operationLoader);
    }); // Short-circuit if *nothing* is referenced


    if (!references.size) {
      this._recordSource.clear();

      return;
    } // Evict any unreferenced nodes


    var storeIDs = this._recordSource.getRecordIDs();

    for (var ii = 0; ii < storeIDs.length; ii++) {
      var dataID = storeIDs[ii];

      if (!references.has(dataID)) {
        this._recordSource.remove(dataID);
      }
    }
  };

  return RelayModernStore;
}();
/**
 * Updates the target with information from source, also updating a mapping of
 * which records in the target were changed as a result.
 */


function updateTargetFromSource(target, source, updatedRecordIDs) {
  var dataIDs = source.getRecordIDs();

  for (var ii = 0; ii < dataIDs.length; ii++) {
    var dataID = dataIDs[ii];
    var sourceRecord = source.get(dataID);
    var targetRecord = target.get(dataID); // Prevent mutation of a record from outside the store.

    if (process.env.NODE_ENV !== "production") {
      if (sourceRecord) {
        require("./RelayModernRecord").freeze(sourceRecord);
      }
    }

    if (sourceRecord === require("./RelayStoreUtils").UNPUBLISH_RECORD_SENTINEL) {
      // Unpublish a record
      target.remove(dataID);
      updatedRecordIDs[dataID] = true;
    } else if (sourceRecord && targetRecord) {
      var nextRecord = require("./RelayModernRecord").update(targetRecord, sourceRecord);

      if (nextRecord !== targetRecord) {
        // Prevent mutation of a record from outside the store.
        if (process.env.NODE_ENV !== "production") {
          require("./RelayModernRecord").freeze(nextRecord);
        }

        updatedRecordIDs[dataID] = true;
        target.set(dataID, nextRecord);
      }
    } else if (sourceRecord === null) {
      target["delete"](dataID);

      if (targetRecord !== null) {
        updatedRecordIDs[dataID] = true;
      }
    } else if (sourceRecord) {
      target.set(dataID, sourceRecord);
      updatedRecordIDs[dataID] = true;
    } // don't add explicit undefined

  }
}

require("./RelayProfiler").instrumentMethods(RelayModernStore.prototype, {
  lookup: 'RelayModernStore.prototype.lookup',
  notify: 'RelayModernStore.prototype.notify',
  publish: 'RelayModernStore.prototype.publish',
  retain: 'RelayModernStore.prototype.retain',
  subscribe: 'RelayModernStore.prototype.subscribe',
  __gc: 'RelayModernStore.prototype.__gc',
  holdGC: 'RelayModernStore.prototype.holdGC'
});

module.exports = RelayModernStore;