microsoft/vscode-react-native

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for details.

import * as fs from "fs";
import * as path from "path";
import * as http from "http";

import {Telemetry} from "../common/telemetry";
import {TelemetryHelper} from "../common/telemetryHelper";

// These typings do not reflect the typings as intended to be used
// but rather as they exist in truth, so we can reach into the internals
// and access what we need.
declare module VSCodeDebugAdapter {
    class DebugSession {
        public static run: Function;
        public sendEvent(event: VSCodeDebugAdapter.InitializedEvent): void;
        public start(input: any, output: any): void;
        public launchRequest(response: any, args: any): void;
    }
    class InitializedEvent {
        constructor();
    }
    class OutputEvent {
        constructor(message: string, destination?: string);
    }
    class TerminatedEvent {
        constructor();
    }
}

declare class SourceMaps {
    public _sourceToGeneratedMaps: {};
    public _generatedToSourceMaps: {};
    public _allSourceMaps: {};
}

declare class NodeDebugSession extends VSCodeDebugAdapter.DebugSession {
    public _sourceMaps: SourceMaps;
}

interface ILaunchArgs {
    platform: string;
    target?: string;
    internalDebuggerPort?: any;
    args: string[];
}

let version = JSON.parse(fs.readFileSync(path.join(__dirname, "..", "..", "package.json"), "utf-8")).version;

// Enable telemetry
Telemetry.init("react-native-debug-adapter", version, true).then(() => {
    let nodeDebugFolder: string;
    let vscodeDebugAdapterPackage: typeof VSCodeDebugAdapter;

    /* tslint:disable:no-var-requires */

    // nodeDebugLocation.json is dynamically generated on extension activation.
    // If it fails, we must not have been in a react native project
    TelemetryHelper.generate("DebuggerSetup", (generator) => {
        return Q({}).then(() => {
            try {
                nodeDebugFolder = require("./nodeDebugLocation.json").nodeDebugPath;
                vscodeDebugAdapterPackage = require(path.join(nodeDebugFolder, "node_modules", "vscode-debugadapter"));
            } catch (e) {
                generator.addError(e);
                // Nothing we can do here: can't even communicate back because we don't know how to speak debug adapter
                process.exit(1);
            }

            // Temporarily dummy out the DebugSession.run function so we do not start the debug adapter until we are ready
            const originalDebugSessionRun = vscodeDebugAdapterPackage.DebugSession.run;
            vscodeDebugAdapterPackage.DebugSession.run = function() { };

            let nodeDebug: { NodeDebugSession: typeof NodeDebugSession };

            try {
                nodeDebug = require(path.join(nodeDebugFolder, "out", "node", "nodeDebug"));
            } catch (e) {
                generator.addError(e);
                // Unable to find nodeDebug, but we can make our own communication channel now
                const debugSession = new vscodeDebugAdapterPackage.DebugSession();
                // Note: this will not work in the context of debugging the debug adapter and communicating over a socket,
                // but in that case we have much better ways to investigate errors.
                debugSession.start(process.stdin, process.stdout);
                debugSession.sendEvent(new vscodeDebugAdapterPackage.OutputEvent("Unable to start debug adapter: " + e.toString(), "stderr"));
                debugSession.sendEvent(new vscodeDebugAdapterPackage.TerminatedEvent());
                process.exit(1);
            }

            /* tslint:enable:no-var-requires */

            vscodeDebugAdapterPackage.DebugSession.run = originalDebugSessionRun;

            // Intecept the "launchRequest" instance method of NodeDebugSession to interpret arguments
            const originalNodeDebugSessionLaunchRequest = nodeDebug.NodeDebugSession.prototype.launchRequest;
            nodeDebug.NodeDebugSession.prototype.launchRequest = function(request: any, args: ILaunchArgs) {
                // Create a server waiting for messages to re-initialize the debug session;
                const reinitializeServer = http.createServer((req, res) => {
                    res.statusCode = 404;
                    if (req.url === "/refreshBreakpoints") {
                        res.statusCode = 200;
                        if (this) {
                            const sourceMaps = this._sourceMaps;
                            if (sourceMaps) {
                                // Flush any cached source maps
                                sourceMaps._allSourceMaps = {};
                                sourceMaps._generatedToSourceMaps = {};
                                sourceMaps._sourceToGeneratedMaps = {};
                            }
                            // Send an "initialized" event to trigger breakpoints to be re-sent
                            this.sendEvent(new vscodeDebugAdapterPackage.InitializedEvent());
                        }
                    }
                    res.end();
                });
                const debugServerListeningPort = parseInt(args.internalDebuggerPort, 10) || 9090;

                reinitializeServer.listen(debugServerListeningPort);
                reinitializeServer.on("error", (err: Error) => {
                    generator.addError(err);
                    this.sendEvent(new vscodeDebugAdapterPackage.OutputEvent("Error in debug adapter server: " + err.toString(), "stderr"));
                    this.sendEvent(new vscodeDebugAdapterPackage.OutputEvent("Breakpoints may not update. Consider restarting and specifying a different 'internalDebuggerPort' in launch.json"));
                });

                // We do not permit arbitrary args to be passed to our process
                args.args = [
                    args.platform,
                    debugServerListeningPort.toString(),
                    args.target || "simulator"
                ];

                originalNodeDebugSessionLaunchRequest.call(this, request, args);
            };

            vscodeDebugAdapterPackage.DebugSession.run(nodeDebug.NodeDebugSession);
        });
    });
});