playwright/src/rpc/server/jsHandleDispatcher.ts

/**
 * Copyright (c) Microsoft Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import * as js from '../../javascript';
import { JSHandleChannel, JSHandleInitializer, SerializedArgument, SerializedValue } from '../channels';
import { Dispatcher, DispatcherScope } from './dispatcher';
import { createHandle } from './elementHandlerDispatcher';
import { parseSerializedValue, serializeValue } from '../serializers';

export class JSHandleDispatcher extends Dispatcher<js.JSHandle, JSHandleInitializer> implements JSHandleChannel {

  constructor(scope: DispatcherScope, jsHandle: js.JSHandle) {
    super(scope, jsHandle, jsHandle.asElement() ? 'ElementHandle' : 'JSHandle', {
      preview: jsHandle.toString(),
    });
    jsHandle._setPreviewCallback(preview => this._dispatchEvent('previewUpdated', { preview }));
  }

  async evaluateExpression(params: { expression: string, isFunction: boolean, arg: SerializedArgument }): Promise<{ value: SerializedValue }> {
    return { value: serializeResult(await this._object._evaluateExpression(params.expression, params.isFunction, true /* returnByValue */, parseArgument(params.arg))) };
  }

  async evaluateExpressionHandle(params: { expression: string, isFunction: boolean, arg: SerializedArgument}): Promise<{ handle: JSHandleChannel }> {
    const jsHandle = await this._object._evaluateExpression(params.expression, params.isFunction, false /* returnByValue */, parseArgument(params.arg));
    return { handle: createHandle(this._scope, jsHandle) };
  }

  async getProperty(params: { name: string }): Promise<{ handle: JSHandleChannel }> {
    const jsHandle = await this._object.getProperty(params.name);
    return { handle: createHandle(this._scope, jsHandle) };
  }

  async getPropertyList(): Promise<{ properties: { name: string, value: JSHandleChannel }[] }> {
    const map = await this._object.getProperties();
    const properties = [];
    for (const [name, value] of map)
      properties.push({ name, value: new JSHandleDispatcher(this._scope, value) });
    return { properties };
  }

  async jsonValue(): Promise<{ value: SerializedValue }> {
    return { value: serializeResult(await this._object.jsonValue()) };
  }

  async dispose() {
    await this._object.dispose();
  }
}

// Generic channel parser converts guids to JSHandleDispatchers,
// and this function takes care of coverting them into underlying JSHandles.
export function parseArgument(arg: SerializedArgument): any {
  return parseSerializedValue(arg.value, arg.handles.map(a => (a as JSHandleDispatcher)._object));
}
export function parseValue(v: SerializedValue): any {
  return parseSerializedValue(v, []);
}

export function serializeResult(arg: any): SerializedValue {
  return serializeValue(arg, value => ({ fallThrough: value }), new Set());
}