prepack/lib/serializer/ResidualHeapValueIdentifiers.js

Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.ResidualHeapValueIdentifiers = void 0;

var _index = require("../values/index.js");

var _invariant = _interopRequireDefault(require("../invariant.js"));

var t = _interopRequireWildcard(require("@babel/types"));

function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = Object.defineProperty && Object.getOwnPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : {}; if (desc.get || desc.set) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } } newObj.default = obj; return newObj; } }

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Copyright (c) 2017-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

/*  strict-local */
// This class maintains a map of values to babel identifiers.
// This class can optionally track how often such value identifiers are referenced
// when pass 1 is activated, which is usually followed by pass 2 in which
// unneeded identifiers (those which were only ever referenced once) are
// eliminated as the defining expression can be inlined.
class ResidualHeapValueIdentifiers {
  constructor(values, preludeGenerator) {
    this.collectValToRefCountOnly = false;
    this._valueNameGenerator = preludeGenerator.createNameGenerator("_");

    this._populateIdentifierMap(values);
  }

  initPass1() {
    this.collectValToRefCountOnly = true;
    this.valToRefCount = new Map();
  }

  initPass2() {
    this.collectValToRefCountOnly = false;
  }

  _populateIdentifierMap(values) {
    this.refs = new Map();

    for (const val of values) {
      this._setIdentifier(val, this._createNewIdentifier(val));
    }
  }

  _createNewIdentifier(val) {
    const name = this._valueNameGenerator.generate(val.__originalName || "");

    return t.identifier(name);
  }

  _setIdentifier(val, id) {
    (0, _invariant.default)(!this.refs.has(val));
    this.refs.set(val, id);
  }

  hasIdentifier(val) {
    return this.refs.has(val);
  }

  getIdentifier(val) {
    let id = this.refs.get(val);
    (0, _invariant.default)(id !== undefined);
    return id;
  }

  deleteIdentifier(val) {
    (0, _invariant.default)(this.refs.has(val));
    this.refs.delete(val);
  }

  getIdentifierAndIncrementReferenceCount(val) {
    this.incrementReferenceCount(val);
    let id = this.refs.get(val);
    (0, _invariant.default)(id !== undefined, "Value Id cannot be null or undefined");
    return id;
  }

  incrementReferenceCount(val) {
    if (this.collectValToRefCountOnly) {
      let valToRefCount = this.valToRefCount;
      (0, _invariant.default)(valToRefCount !== undefined);
      let refCount = valToRefCount.get(val);

      if (refCount !== undefined) {
        refCount++;
      } else {
        refCount = 1;
      }

      valToRefCount.set(val, refCount);
    }
  }

  needsIdentifier(val) {
    if (this.collectValToRefCountOnly || this.valToRefCount === undefined) return true;
    let refCount = this.valToRefCount.get(val);
    (0, _invariant.default)(refCount !== undefined && refCount > 0);
    return refCount !== 1;
  }

}

exports.ResidualHeapValueIdentifiers = ResidualHeapValueIdentifiers;
//# sourceMappingURL=ResidualHeapValueIdentifiers.js.map