prepack/lib/serializer/visitors.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.ClosureRefVisitor = void 0;

var _realm = require("../realm.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; } }

/**
 * 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 */
function visitName(path, state, node, modified) {
  // Is the name bound to some local identifier? If so, we don't need to do anything
  if (path.scope.hasBinding(node.name,
  /*noGlobals*/
  true)) return; // Otherwise, let's record that there's an unbound identifier

  let nodes = state.functionInfo.unbound.get(node.name);
  if (nodes === undefined) state.functionInfo.unbound.set(node.name, nodes = []);
  nodes.push(node);
  if (modified) state.functionInfo.modified.add(node.name);
}

function ignorePath(path) {
  let parent = path.parent;
  return t.isLabeledStatement(parent) || t.isBreakStatement(parent) || t.isContinueStatement(parent);
}

let ClosureRefVisitor = {
  "FunctionDeclaration|ArrowFunctionExpression|FunctionExpression": {
    enter(path, state) {
      state.functionInfo.depth++;
    },

    exit(path, state) {
      state.functionInfo.depth--;
    }

  },
  ArrowFunctionExpression: {
    enter(path, state) {
      state.functionInfo.depth++;
      state.functionInfo.lexicalDepth++;
    },

    exit(path, state) {
      state.functionInfo.depth--;
      state.functionInfo.lexicalDepth--;
    }

  },

  CallExpression(path, state) {
    // Here we apply the require optimization by replacing require calls with their
    // corresponding initialized modules.
    if (state.getModuleIdIfNodeIsRequireFunction === undefined) return;
    let moduleId = state.getModuleIdIfNodeIsRequireFunction(path.scope, path.node);
    if (moduleId === undefined) return;
    state.functionInfo.requireCalls.set(path.node, moduleId);
  },

  ReferencedIdentifier(path, state) {
    if (ignorePath(path)) return;
    let innerName = path.node.name;

    if (innerName === "arguments") {
      if (state.functionInfo.depth === 1) {
        state.functionInfo.usesArguments = true;
      } // "arguments" bound to local scope. therefore, there's no need to visit this identifier.


      return;
    }

    visitName(path, state, path.node, false);
  },

  ThisExpression(path, state) {
    if (state.functionInfo.depth - state.functionInfo.lexicalDepth === 1) {
      state.functionInfo.usesThis = true;
    }
  },

  "AssignmentExpression|UpdateExpression"(path, state) {
    let ids = path.getBindingIdentifiers();

    for (let name in ids) {
      visitName(path, state, ids[name], true);
    }
  },

  "ForInStatement|ForOfStatement"(path, state) {
    if (path.node.left !== "VariableDeclaration") {
      // `LeftHandSideExpression`s in a for-in/for-of statement perform `DestructuringAssignment` on the current loop
      // value so we need to make sure we visit these bindings and mark them as modified.
      const ids = path.get("left").getBindingIdentifiers();

      for (const name in ids) {
        visitName(path, state, ids[name], true);
      }
    }
  }

};
exports.ClosureRefVisitor = ClosureRefVisitor;
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