prepack/lib/debugger/server/Stepper.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.StepOverStepper = exports.StepIntoStepper = exports.Stepper = undefined;

var _is = require("./../../methods/is.js");

var _babelTypes = require("babel-types");

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

var _invariant2 = _interopRequireDefault(_invariant);

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.
 */

class Stepper {
  constructor(filePath, line, column) {
    this._stepStartData = {
      filePath: filePath,
      line: line,
      column: column
    };
  }


  isComplete(ast, currentStackSize) {
    (0, _invariant2.default)(false, "Abstract method, please override");
  }

  isAstLocationChanged(ast) {
    // we should only step to statements
    if (!(0, _is.IsStatement)(ast)) return false;
    let loc = ast.loc;
    if (!loc) return false;
    let filePath = loc.source;
    let line = loc.start.line;
    let column = loc.start.column;
    if (!filePath) return false;
    if (this._stepStartData) {
      if (filePath === this._stepStartData.filePath && line === this._stepStartData.line && column === this._stepStartData.column) {
        return false;
      }
    } else {
      return false;
    }
    return true;
  }
}

exports.Stepper = Stepper;
class StepIntoStepper extends Stepper {
  constructor(filePath, line, column) {
    super(filePath, line, column);
  }

  // Override
  isComplete(ast, currentStackSize) {
    return this.isAstLocationChanged(ast);
  }
}

exports.StepIntoStepper = StepIntoStepper;
class StepOverStepper extends Stepper {
  constructor(filePath, line, column, stackSize) {
    super(filePath, line, column);
    this._startStackSize = stackSize;
  }


  isComplete(ast, currentStackSize) {
    if (!this.isAstLocationChanged(ast)) return false;
    if (currentStackSize <= this._startStackSize) {
      // two cases here:
      // if current stack length < starting stack length, the program must have
      // hit an exception so this stepper is no longer relevant
      // if current stack length === starting stack length, the program returned
      // to the same stack depth, so a step over is complete
      return true;
    }
    return false;
  }
}
exports.StepOverStepper = StepOverStepper;
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