GDBDebugSession.ts

/*********************************************************************
 * Copyright (c) 2018 QNX Software Systems and others
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *********************************************************************/
import * as os from 'os';
import * as path from 'path';
import {
    Handles,
    InitializedEvent,
    Logger,
    logger,
    LoggingDebugSession,
    OutputEvent,
    Response,
    Scope,
    Source,
    StackFrame,
    TerminatedEvent,
} from '@vscode/debugadapter';
import { DebugProtocol } from '@vscode/debugprotocol';
import { GDBBackend } from './GDBBackend';
import * as mi from './mi';
import {
    sendDataReadMemoryBytes,
    sendDataDisassemble,
    sendDataWriteMemoryBytes,
} from './mi/data';
import { StoppedEvent } from './stoppedEvent';
import { VarObjType } from './varManager';
import { breakpointFunctionLocation, breakpointLocation } from './mi';

export interface RequestArguments extends DebugProtocol.LaunchRequestArguments {
    gdb?: string;
    gdbArguments?: string[];
    gdbAsync?: boolean;
    gdbNonStop?: boolean;
    program: string;
    cwd?: string; // TODO not implemented
    verbose?: boolean;
    logFile?: string;
    openGdbConsole?: boolean;
    initCommands?: string[];
}

export interface LaunchRequestArguments extends RequestArguments {
    arguments?: string;
}

export interface AttachRequestArguments extends RequestArguments {
    processId: string;
}

export interface FrameReference {
    threadId: number;
    frameId: number;
}

export interface FrameVariableReference {
    type: 'frame';
    frameHandle: number;
}

export interface ObjectVariableReference {
    type: 'object';
    frameHandle: number;
    varobjName: string;
}

export interface RegisterVariableReference {
    type: 'registers';
    frameHandle: number;
    regname?: string;
}

export type VariableReference =
    | FrameVariableReference
    | ObjectVariableReference
    | RegisterVariableReference;

export interface MemoryRequestArguments {
    address: string;
    length: number;
    offset?: number;
}

/**
 * Response for our custom 'cdt-gdb-adapter/Memory' request.
 */
export interface MemoryContents {
    /* Hex-encoded string of bytes.  */
    data: string;
    address: string;
}

export interface MemoryResponse extends Response {
    body: MemoryContents;
}

export interface CDTDisassembleArguments
    extends DebugProtocol.DisassembleArguments {
    /**
     * Memory reference to the end location containing the instructions to disassemble. When this
     * optional setting is provided, the minimum number of lines needed to get to the endMemoryReference
     * is used.
     */
    endMemoryReference: string;
}

class ThreadWithStatus implements DebugProtocol.Thread {
    id: number;
    name: string;
    running: boolean;
    constructor(id: number, name: string, running: boolean) {
        this.id = id;
        this.name = name;
        this.running = running;
    }
}

// Allow a single number for ignore count or the form '> [number]'
const ignoreCountRegex = /\s|>/g;
const arrayRegex = /.*\[[\d]+\].*/;
const arrayChildRegex = /[\d]+/;

export function hexToBase64(hex: string): string {
    // The buffer will ignore incomplete bytes (unpaired digits), so we need to catch that early
    if (hex.length % 2 !== 0) {
        throw new Error('Received memory with incomplete bytes.');
    }
    const base64 = Buffer.from(hex, 'hex').toString('base64');
    // If the hex input includes characters that are not hex digits, Buffer.from() will return an empty buffer, and the base64 string will be empty.
    if (base64.length === 0 && hex.length !== 0) {
        throw new Error('Received ill-formed hex input: ' + hex);
    }
    return base64;
}

export function base64ToHex(base64: string): string {
    const buffer = Buffer.from(base64, 'base64');
    // The caller likely passed in a value that left dangling bits that couldn't be assigned to a full byte and so
    // were ignored by Buffer. We can't be sure what the client thought they wanted to do with those extra bits, so fail here.
    if (buffer.length === 0 || !buffer.toString('base64').startsWith(base64)) {
        throw new Error('Received ill-formed base64 input: ' + base64);
    }
    return buffer.toString('hex');
}

export class GDBDebugSession extends LoggingDebugSession {
    protected gdb: GDBBackend = this.createBackend();
    protected isAttach = false;
    // isRunning === true means there are no threads stopped.
    protected isRunning = false;

    protected supportsRunInTerminalRequest = false;
    protected supportsGdbConsole = false;

    /* A reference to the logger to be used by subclasses */
    protected logger: Logger.Logger;

    protected frameHandles = new Handles<FrameReference>();
    protected variableHandles = new Handles<VariableReference>();
    protected functionBreakpoints: string[] = [];
    protected logPointMessages: { [key: string]: string } = {};

    protected threads: ThreadWithStatus[] = [];

    protected waitPaused?: (value?: void | PromiseLike<void>) => void;
    protected isInitialized = false;

    constructor() {
        super();
        this.logger = logger;
    }

    protected createBackend(): GDBBackend {
        return new GDBBackend();
    }

    /**
     * Handle requests not defined in the debug adapter protocol.
     */
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    protected customRequest(
        command: string,
        response: DebugProtocol.Response,
        args: any
    ): void {
        if (command === 'cdt-gdb-adapter/Memory') {
            this.memoryRequest(response as MemoryResponse, args);
            // This custom request exists to allow tests in this repository to run arbitrary commands
            // Use at your own risk!
        } else if (command === 'cdt-gdb-tests/executeCommand') {
            this.gdb
                .sendCommand(args.command)
                .then(() => {
                    response.body = 'Ok';
                    this.sendResponse(response);
                })
                .catch((e) => {
                    const message =
                        e instanceof Error
                            ? e.message
                            : `Encountered a problem executing ${args.command}`;
                    this.sendErrorResponse(response, 1, message);
                });
        } else {
            return super.customRequest(command, response, args);
        }
    }

    protected initializeRequest(
        response: DebugProtocol.InitializeResponse,
        args: DebugProtocol.InitializeRequestArguments
    ): void {
        this.supportsRunInTerminalRequest =
            args.supportsRunInTerminalRequest === true;
        this.supportsGdbConsole =
            os.platform() === 'linux' && this.supportsRunInTerminalRequest;
        response.body = response.body || {};
        response.body.supportsConfigurationDoneRequest = true;
        response.body.supportsSetVariable = true;
        response.body.supportsConditionalBreakpoints = true;
        response.body.supportsHitConditionalBreakpoints = true;
        response.body.supportsLogPoints = true;
        response.body.supportsFunctionBreakpoints = true;
        // response.body.supportsSetExpression = true;
        response.body.supportsDisassembleRequest = true;
        response.body.supportsReadMemoryRequest = true;
        response.body.supportsWriteMemoryRequest = true;
        this.sendResponse(response);
    }

    protected async attachRequest(
        response: DebugProtocol.AttachResponse,
        args: AttachRequestArguments
    ): Promise<void> {
        try {
            logger.setup(
                args.verbose ? Logger.LogLevel.Verbose : Logger.LogLevel.Warn,
                args.logFile || false
            );

            this.gdb.on('consoleStreamOutput', (output, category) => {
                this.sendEvent(new OutputEvent(output, category));
            });

            this.gdb.on('execAsync', (resultClass, resultData) =>
                this.handleGDBAsync(resultClass, resultData)
            );
            this.gdb.on('notifyAsync', (resultClass, resultData) =>
                this.handleGDBNotify(resultClass, resultData)
            );

            await this.spawn(args);
            await this.gdb.sendFileExecAndSymbols(args.program);
            await this.gdb.sendEnablePrettyPrint();

            await mi.sendTargetAttachRequest(this.gdb, { pid: args.processId });
            this.sendEvent(
                new OutputEvent(`attached to process ${args.processId}`)
            );
            await this.gdb.sendCommands(args.initCommands);

            this.sendEvent(new InitializedEvent());
            this.sendResponse(response);
            this.isInitialized = true;
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async launchRequest(
        response: DebugProtocol.LaunchResponse,
        args: LaunchRequestArguments
    ): Promise<void> {
        try {
            logger.setup(
                args.verbose ? Logger.LogLevel.Verbose : Logger.LogLevel.Warn,
                args.logFile || false
            );

            this.gdb.on('consoleStreamOutput', (output, category) => {
                this.sendEvent(new OutputEvent(output, category));
            });

            this.gdb.on('execAsync', (resultClass, resultData) =>
                this.handleGDBAsync(resultClass, resultData)
            );
            this.gdb.on('notifyAsync', (resultClass, resultData) =>
                this.handleGDBNotify(resultClass, resultData)
            );

            await this.spawn(args);
            await this.gdb.sendFileExecAndSymbols(args.program);
            await this.gdb.sendEnablePrettyPrint();

            if (args.initCommands) {
                for (const command of args.initCommands) {
                    await this.gdb.sendCommand(command);
                }
            }

            if (args.arguments) {
                await mi.sendExecArguments(this.gdb, {
                    arguments: args.arguments,
                });
            }
            this.sendEvent(new InitializedEvent());
            this.sendResponse(response);
            this.isInitialized = true;
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async spawn(
        args: LaunchRequestArguments | AttachRequestArguments
    ) {
        if (args.openGdbConsole) {
            if (!this.supportsGdbConsole) {
                logger.warn(
                    'cdt-gdb-adapter: openGdbConsole is not supported on this platform'
                );
            } else if (!(await this.gdb.supportsNewUi(args.gdb))) {
                logger.warn(
                    `cdt-gdb-adapter: new-ui command not detected (${
                        args.gdb || 'gdb'
                    })`
                );
            } else {
                logger.verbose(
                    'cdt-gdb-adapter: spawning gdb console in client terminal'
                );
                return this.spawnInClientTerminal(args);
            }
        }
        return this.gdb.spawn(args);
    }

    protected async spawnInClientTerminal(
        args:
            | DebugProtocol.LaunchRequestArguments
            | DebugProtocol.AttachRequestArguments
    ) {
        return this.gdb.spawnInClientTerminal(
            args as LaunchRequestArguments | AttachRequestArguments,
            async (command) => {
                const response = await new Promise<DebugProtocol.Response>(
                    (resolve) =>
                        this.sendRequest(
                            'runInTerminal',
                            {
                                kind: 'integrated',
                                cwd: process.cwd(),
                                env: process.env,
                                args: command,
                            } as DebugProtocol.RunInTerminalRequestArguments,
                            5000,
                            resolve
                        )
                );
                if (!response.success) {
                    const message = `could not start the terminal on the client: ${response.message}`;
                    logger.error(message);
                    throw new Error(message);
                }
            }
        );
    }

    protected async setBreakPointsRequest(
        response: DebugProtocol.SetBreakpointsResponse,
        args: DebugProtocol.SetBreakpointsArguments
    ): Promise<void> {
        const neededPause = this.isRunning;
        if (neededPause) {
            // Need to pause first
            const waitPromise = new Promise<void>((resolve) => {
                this.waitPaused = resolve;
            });
            this.gdb.pause();
            await waitPromise;
        }

        try {
            // Need to get the list of current breakpoints in the file and then make sure
            // that we end up with the requested set of breakpoints for that file
            // deleting ones not requested and inserting new ones.

            const result = await mi.sendBreakList(this.gdb);
            const file = args.source.path as string;
            const gdbOriginalLocationPrefix = await breakpointLocation(
                this.gdb,
                file
            );
            const gdbbps = result.BreakpointTable.body.filter((gdbbp) => {
                // Ignore "children" breakpoint of <MULTIPLE> entries
                if (gdbbp.number.includes('.')) {
                    return false;
                }

                // Ignore other files
                if (!gdbbp['original-location']) {
                    return false;
                }
                if (
                    !gdbbp['original-location'].startsWith(
                        gdbOriginalLocationPrefix
                    )
                ) {
                    return false;
                }

                // Ignore function breakpoints
                return this.functionBreakpoints.indexOf(gdbbp.number) === -1;
            });

            const { resolved, deletes } = this.resolveBreakpoints(
                args.breakpoints || [],
                gdbbps,
                (vsbp, gdbbp) => {
                    // Always invalidate hit conditions as they have a one-way mapping to gdb ignore and temporary
                    if (vsbp.hitCondition) {
                        return false;
                    }

                    // Ensure we can compare undefined and empty strings
                    const vsbpCond = vsbp.condition || undefined;
                    const gdbbpCond = gdbbp.cond || undefined;

                    // Check with original-location so that relocated breakpoints are properly matched
                    const gdbOriginalLocation = `${gdbOriginalLocationPrefix}${vsbp.line}`;
                    return !!(
                        gdbbp['original-location'] === gdbOriginalLocation &&
                        vsbpCond === gdbbpCond
                    );
                }
            );

            // Delete before insert to avoid breakpoint clashes in gdb
            if (deletes.length > 0) {
                await mi.sendBreakDelete(this.gdb, { breakpoints: deletes });
                deletes.forEach(
                    (breakpoint) => delete this.logPointMessages[breakpoint]
                );
            }

            // Reset logPoints
            this.logPointMessages = {};

            // Set up logpoint messages and return a formatted breakpoint for the response body
            const createState = (
                vsbp: DebugProtocol.SourceBreakpoint,
                gdbbp: mi.MIBreakpointInfo
            ): DebugProtocol.Breakpoint => {
                if (vsbp.logMessage) {
                    this.logPointMessages[gdbbp.number] = vsbp.logMessage;
                }

                let line = 0;
                if (gdbbp.line) {
                    line = parseInt(gdbbp.line, 10);
                } else if (vsbp.line) {
                    line = vsbp.line;
                }

                return {
                    id: parseInt(gdbbp.number, 10),
                    line,
                    verified: true,
                };
            };

            const actual: DebugProtocol.Breakpoint[] = [];

            for (const bp of resolved) {
                if (bp.gdbbp) {
                    actual.push(createState(bp.vsbp, bp.gdbbp));
                    continue;
                }

                let temporary = false;
                let ignoreCount: number | undefined;
                const vsbp = bp.vsbp;
                if (vsbp.hitCondition !== undefined) {
                    ignoreCount = parseInt(
                        vsbp.hitCondition.replace(ignoreCountRegex, ''),
                        10
                    );
                    if (isNaN(ignoreCount)) {
                        this.sendEvent(
                            new OutputEvent(
                                `Unable to decode expression: ${vsbp.hitCondition}`
                            )
                        );
                        continue;
                    }

                    // Allow hit condition continuously above the count
                    temporary = !vsbp.hitCondition.startsWith('>');
                    if (temporary) {
                        // The expression is not 'greater than', decrease ignoreCount to match
                        ignoreCount--;
                    }
                }

                try {
                    const gdbbp = await mi.sendBreakInsert(this.gdb, {
                        source: file,
                        line: vsbp.line,
                        condition: vsbp.condition,
                        temporary,
                        ignoreCount,
                    });
                    actual.push(createState(vsbp, gdbbp.bkpt));
                } catch (err) {
                    actual.push({
                        verified: false,
                        message:
                            err instanceof Error ? err.message : String(err),
                    } as DebugProtocol.Breakpoint);
                }
            }

            response.body = {
                breakpoints: actual,
            };

            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }

        if (neededPause) {
            mi.sendExecContinue(this.gdb);
        }
    }

    protected async setFunctionBreakPointsRequest(
        response: DebugProtocol.SetFunctionBreakpointsResponse,
        args: DebugProtocol.SetFunctionBreakpointsArguments
    ) {
        const neededPause = this.isRunning;
        if (neededPause) {
            // Need to pause first
            const waitPromise = new Promise<void>((resolve) => {
                this.waitPaused = resolve;
            });
            this.gdb.pause();
            await waitPromise;
        }

        try {
            const result = await mi.sendBreakList(this.gdb);
            const gdbbps = result.BreakpointTable.body.filter((gdbbp) => {
                // Only function breakpoints
                return this.functionBreakpoints.indexOf(gdbbp.number) > -1;
            });

            const { resolved, deletes } = this.resolveBreakpoints(
                args.breakpoints,
                gdbbps,
                (vsbp, gdbbp) => {
                    // Always invalidate hit conditions as they have a one-way mapping to gdb ignore and temporary
                    if (vsbp.hitCondition) {
                        return false;
                    }

                    // Ensure we can compare undefined and empty strings
                    const vsbpCond = vsbp.condition || undefined;
                    const gdbbpCond = gdbbp.cond || undefined;

                    const originalLocation = breakpointFunctionLocation(
                        this.gdb,
                        vsbp.name
                    );
                    return !!(
                        gdbbp['original-location'] === originalLocation &&
                        vsbpCond === gdbbpCond
                    );
                }
            );

            // Delete before insert to avoid breakpoint clashes in gdb
            if (deletes.length > 0) {
                await mi.sendBreakDelete(this.gdb, { breakpoints: deletes });
                this.functionBreakpoints = this.functionBreakpoints.filter(
                    (fnbp) => deletes.indexOf(fnbp) === -1
                );
            }

            const createActual = (
                breakpoint: mi.MIBreakpointInfo
            ): DebugProtocol.Breakpoint => ({
                id: parseInt(breakpoint.number, 10),
                verified: true,
            });

            const actual: DebugProtocol.Breakpoint[] = [];
            // const actual = existing.map((bp) => createActual(bp.gdbbp));

            for (const bp of resolved) {
                if (bp.gdbbp) {
                    actual.push(createActual(bp.gdbbp));
                    continue;
                }

                try {
                    const gdbbp = await mi.sendBreakFunctionInsert(
                        this.gdb,
                        bp.vsbp.name
                    );
                    this.functionBreakpoints.push(gdbbp.bkpt.number);
                    actual.push(createActual(gdbbp.bkpt));
                } catch (err) {
                    actual.push({
                        verified: false,
                        message:
                            err instanceof Error ? err.message : String(err),
                    } as DebugProtocol.Breakpoint);
                }
            }

            response.body = {
                breakpoints: actual,
            };

            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }

        if (neededPause) {
            mi.sendExecContinue(this.gdb);
        }
    }

    /**
     * Resolved which VS breakpoints needs to be installed, which
     * GDB breakpoints need to be deleted and which VS breakpoints
     * are already installed with which matching GDB breakpoint.
     * @param vsbps VS DAP breakpoints
     * @param gdbbps GDB breakpoints
     * @param matchFn matcher to compare VS and GDB breakpoints
     * @returns resolved -> array maintaining order of vsbps that identifies whether
     * VS breakpoint has a cooresponding GDB breakpoint (gdbbp field set) or needs to be
     * inserted (gdbbp field empty)
     * deletes -> GDB bps ids that should be deleted because they don't match vsbps
     */
    protected resolveBreakpoints<T>(
        vsbps: T[],
        gdbbps: mi.MIBreakpointInfo[],
        matchFn: (vsbp: T, gdbbp: mi.MIBreakpointInfo) => boolean
    ): {
        resolved: Array<{ vsbp: T; gdbbp?: mi.MIBreakpointInfo }>;
        deletes: string[];
    } {
        const resolved: Array<{ vsbp: T; gdbbp?: mi.MIBreakpointInfo }> =
            vsbps.map((vsbp) => {
                return {
                    vsbp,
                    gdbbp: gdbbps.find((gdbbp) => matchFn(vsbp, gdbbp)),
                };
            });

        const deletes = gdbbps
            .filter((gdbbp) => {
                return !vsbps.find((vsbp) => matchFn(vsbp, gdbbp));
            })
            .map((gdbbp) => gdbbp.number);

        return { resolved, deletes };
    }

    protected async configurationDoneRequest(
        response: DebugProtocol.ConfigurationDoneResponse,
        _args: DebugProtocol.ConfigurationDoneArguments
    ): Promise<void> {
        try {
            if (this.isAttach) {
                await mi.sendExecContinue(this.gdb);
            } else {
                await mi.sendExecRun(this.gdb);
            }
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                100,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected convertThread(thread: mi.MIThreadInfo) {
        let name = thread.name || thread.id;

        if (thread.details) {
            name += ` (${thread.details})`;
        }

        const running = thread.state === 'running';

        return new ThreadWithStatus(parseInt(thread.id, 10), name, running);
    }

    protected async threadsRequest(
        response: DebugProtocol.ThreadsResponse
    ): Promise<void> {
        try {
            if (!this.isRunning) {
                const result = await mi.sendThreadInfoRequest(this.gdb, {});
                this.threads = result.threads.map((thread) =>
                    this.convertThread(thread)
                );
            }

            response.body = {
                threads: this.threads,
            };

            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async stackTraceRequest(
        response: DebugProtocol.StackTraceResponse,
        args: DebugProtocol.StackTraceArguments
    ): Promise<void> {
        try {
            const threadId = args.threadId;
            const depthResult = await mi.sendStackInfoDepth(this.gdb, {
                maxDepth: 100,
                threadId,
            });
            const depth = parseInt(depthResult.depth, 10);
            const levels = args.levels
                ? args.levels > depth
                    ? depth
                    : args.levels
                : depth;
            const lowFrame = args.startFrame || 0;
            const highFrame = lowFrame + levels - 1;
            const listResult = await mi.sendStackListFramesRequest(this.gdb, {
                lowFrame,
                highFrame,
                threadId,
            });

            const stack = listResult.stack.map((frame) => {
                let source;
                if (frame.fullname) {
                    source = new Source(
                        path.basename(frame.file || frame.fullname),
                        frame.fullname
                    );
                }
                let line;
                if (frame.line) {
                    line = parseInt(frame.line, 10);
                }
                const frameHandle = this.frameHandles.create({
                    threadId: args.threadId,
                    frameId: parseInt(frame.level, 10),
                });
                const name = frame.func || frame.fullname || '';
                const sf = new StackFrame(
                    frameHandle,
                    name,
                    source,
                    line
                ) as DebugProtocol.StackFrame;
                sf.instructionPointerReference = frame.addr;
                return sf;
            });

            response.body = {
                stackFrames: stack,
                totalFrames: depth,
            };

            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async nextRequest(
        response: DebugProtocol.NextResponse,
        args: DebugProtocol.NextArguments
    ): Promise<void> {
        try {
            await mi.sendExecNext(this.gdb, args.threadId);
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async stepInRequest(
        response: DebugProtocol.StepInResponse,
        args: DebugProtocol.StepInArguments
    ): Promise<void> {
        try {
            await mi.sendExecStep(this.gdb, args.threadId);
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async stepOutRequest(
        response: DebugProtocol.StepOutResponse,
        args: DebugProtocol.StepOutArguments
    ): Promise<void> {
        try {
            await mi.sendExecFinish(this.gdb, args.threadId);
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async continueRequest(
        response: DebugProtocol.ContinueResponse,
        args: DebugProtocol.ContinueArguments
    ): Promise<void> {
        try {
            await mi.sendExecContinue(this.gdb, args.threadId);
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async pauseRequest(
        response: DebugProtocol.PauseResponse,
        args: DebugProtocol.PauseArguments
    ): Promise<void> {
        try {
            this.gdb.pause(args.threadId);
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected scopesRequest(
        response: DebugProtocol.ScopesResponse,
        args: DebugProtocol.ScopesArguments
    ): void {
        const frame: FrameVariableReference = {
            type: 'frame',
            frameHandle: args.frameId,
        };

        const registers: RegisterVariableReference = {
            type: 'registers',
            frameHandle: args.frameId,
        };

        response.body = {
            scopes: [
                new Scope('Local', this.variableHandles.create(frame), false),
                new Scope(
                    'Registers',
                    this.variableHandles.create(registers),
                    true
                ),
            ],
        };

        this.sendResponse(response);
    }

    protected async variablesRequest(
        response: DebugProtocol.VariablesResponse,
        args: DebugProtocol.VariablesArguments
    ): Promise<void> {
        const variables = new Array<DebugProtocol.Variable>();
        response.body = {
            variables,
        };
        try {
            const ref = this.variableHandles.get(args.variablesReference);
            if (!ref) {
                this.sendResponse(response);
                return;
            }
            if (ref.type === 'registers') {
                response.body.variables =
                    await this.handleVariableRequestRegister(ref);
            } else if (ref.type === 'frame') {
                response.body.variables = await this.handleVariableRequestFrame(
                    ref
                );
            } else if (ref.type === 'object') {
                response.body.variables =
                    await this.handleVariableRequestObject(ref);
            }
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async setVariableRequest(
        response: DebugProtocol.SetVariableResponse,
        args: DebugProtocol.SetVariableArguments
    ): Promise<void> {
        try {
            const ref = this.variableHandles.get(args.variablesReference);
            if (!ref) {
                this.sendResponse(response);
                return;
            }
            const frame = this.frameHandles.get(ref.frameHandle);
            if (!frame) {
                this.sendResponse(response);
                return;
            }
            const parentVarname = ref.type === 'object' ? ref.varobjName : '';
            const varname =
                parentVarname +
                (parentVarname === '' ? '' : '.') +
                args.name.replace(/^\[(\d+)\]/, '$1');
            const stackDepth = await mi.sendStackInfoDepth(this.gdb, {
                maxDepth: 100,
            });
            const depth = parseInt(stackDepth.depth, 10);
            let varobj = this.gdb.varManager.getVar(
                frame.frameId,
                frame.threadId,
                depth,
                varname
            );
            let assign;
            if (varobj) {
                assign = await mi.sendVarAssign(this.gdb, {
                    varname: varobj.varname,
                    expression: args.value,
                });
            } else {
                try {
                    assign = await mi.sendVarAssign(this.gdb, {
                        varname,
                        expression: args.value,
                    });
                } catch (err) {
                    if (parentVarname === '') {
                        throw err; // no recovery possible
                    }
                    const children = await mi.sendVarListChildren(this.gdb, {
                        name: parentVarname,
                        printValues: mi.MIVarPrintValues.all,
                    });
                    for (const child of children.children) {
                        if (this.isChildOfClass(child)) {
                            const grandchildVarname =
                                child.name +
                                '.' +
                                args.name.replace(/^\[(\d+)\]/, '$1');
                            varobj = this.gdb.varManager.getVar(
                                frame.frameId,
                                frame.threadId,
                                depth,
                                grandchildVarname
                            );
                            try {
                                assign = await mi.sendVarAssign(this.gdb, {
                                    varname: grandchildVarname,
                                    expression: args.value,
                                });
                                break;
                            } catch (err) {
                                continue; // try another child
                            }
                        }
                    }
                    if (!assign) {
                        throw err; // no recovery possible
                    }
                }
            }
            response.body = {
                value: assign.value,
                type: varobj ? varobj.type : undefined,
                variablesReference:
                    varobj && parseInt(varobj.numchild, 10) > 0
                        ? this.variableHandles.create({
                              type: 'object',
                              frameHandle: ref.frameHandle,
                              varobjName: varobj.varname,
                          })
                        : 0,
            };
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
        this.sendResponse(response);
    }

    // protected async setExpressionRequest(response: DebugProtocol.SetExpressionResponse,
    //                                      args: DebugProtocol.SetExpressionArguments): Promise<void> {
    //     logger.error('got setExpressionRequest');
    //     this.sendResponse(response);
    // }

    protected async evaluateRequest(
        response: DebugProtocol.EvaluateResponse,
        args: DebugProtocol.EvaluateArguments
    ): Promise<void> {
        response.body = {
            result: 'Error: could not evaluate expression',
            variablesReference: 0,
        }; // default response
        try {
            if (args.frameId === undefined) {
                throw new Error(
                    'Evaluation of expression without frameId is not supported.'
                );
            }

            const frame = this.frameHandles.get(args.frameId);
            if (!frame) {
                this.sendResponse(response);
                return;
            }
            const stackDepth = await mi.sendStackInfoDepth(this.gdb, {
                maxDepth: 100,
            });
            const depth = parseInt(stackDepth.depth, 10);
            let varobj = this.gdb.varManager.getVar(
                frame.frameId,
                frame.threadId,
                depth,
                args.expression
            );
            if (!varobj) {
                const varCreateResponse = await mi.sendVarCreate(this.gdb, {
                    expression: args.expression,
                    frameId: frame.frameId,
                    threadId: frame.threadId,
                });
                varobj = this.gdb.varManager.addVar(
                    frame.frameId,
                    frame.threadId,
                    depth,
                    args.expression,
                    false,
                    false,
                    varCreateResponse
                );
            } else {
                const vup = await mi.sendVarUpdate(this.gdb, {
                    name: varobj.varname,
                });
                const update = vup.changelist[0];
                if (update) {
                    if (update.in_scope === 'true') {
                        if (update.name === varobj.varname) {
                            varobj.value = update.value;
                        }
                    } else {
                        this.gdb.varManager.removeVar(
                            frame.frameId,
                            frame.threadId,
                            depth,
                            varobj.varname
                        );
                        await mi.sendVarDelete(this.gdb, {
                            varname: varobj.varname,
                        });
                        const varCreateResponse = await mi.sendVarCreate(
                            this.gdb,
                            {
                                expression: args.expression,
                                frameId: frame.frameId,
                                threadId: frame.threadId,
                            }
                        );
                        varobj = this.gdb.varManager.addVar(
                            frame.frameId,
                            frame.threadId,
                            depth,
                            args.expression,
                            false,
                            false,
                            varCreateResponse
                        );
                    }
                }
            }
            if (varobj) {
                response.body = {
                    result: varobj.value,
                    type: varobj.type,
                    variablesReference:
                        parseInt(varobj.numchild, 10) > 0
                            ? this.variableHandles.create({
                                  type: 'object',
                                  frameHandle: args.frameId,
                                  varobjName: varobj.varname,
                              })
                            : 0,
                };
            }

            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    /**
     * Implement the cdt-gdb-adapter/Memory request.
     */
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    protected async memoryRequest(response: MemoryResponse, args: any) {
        try {
            if (typeof args.address !== 'string') {
                throw new Error(
                    `Invalid type for 'address', expected string, got ${typeof args.address}`
                );
            }

            if (typeof args.length !== 'number') {
                throw new Error(
                    `Invalid type for 'length', expected number, got ${typeof args.length}`
                );
            }

            if (
                typeof args.offset !== 'number' &&
                typeof args.offset !== 'undefined'
            ) {
                throw new Error(
                    `Invalid type for 'offset', expected number or undefined, got ${typeof args.offset}`
                );
            }

            const typedArgs = args as MemoryRequestArguments;

            const result = await sendDataReadMemoryBytes(
                this.gdb,
                typedArgs.address,
                typedArgs.length,
                typedArgs.offset
            );
            response.body = {
                data: result.memory[0].contents,
                address: result.memory[0].begin,
            };
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async disassembleRequest(
        response: DebugProtocol.DisassembleResponse,
        args: CDTDisassembleArguments
    ) {
        try {
            const meanSizeOfInstruction = 4;
            let startOffset = 0;
            let lastStartOffset = -1;
            const instructions: DebugProtocol.DisassembledInstruction[] = [];
            let oneIterationOnly = false;
            outer_loop: while (
                instructions.length < args.instructionCount &&
                !oneIterationOnly
            ) {
                if (startOffset === lastStartOffset) {
                    // We have stopped getting new instructions, give up
                    break outer_loop;
                }
                lastStartOffset = startOffset;

                const fetchSize =
                    (args.instructionCount - instructions.length) *
                    meanSizeOfInstruction;

                // args.memoryReference is an arbitrary expression, so let GDB do the
                // math on resolving value rather than doing the addition in the adapter
                try {
                    const stepStartAddress = `(${args.memoryReference})+${startOffset}`;
                    let stepEndAddress = `(${args.memoryReference})+${startOffset}+${fetchSize}`;
                    if (args.endMemoryReference && instructions.length === 0) {
                        // On the first call, if we have an end memory address use it instead of
                        // the approx size
                        stepEndAddress = args.endMemoryReference;
                        oneIterationOnly = true;
                    }
                    const result = await sendDataDisassemble(
                        this.gdb,
                        stepStartAddress,
                        stepEndAddress
                    );
                    for (const asmInsn of result.asm_insns) {
                        const line: number | undefined = asmInsn.line
                            ? parseInt(asmInsn.line, 10)
                            : undefined;
                        const source = {
                            name: asmInsn.file,
                            path: asmInsn.fullname,
                        } as DebugProtocol.Source;
                        for (const asmLine of asmInsn.line_asm_insn) {
                            let funcAndOffset: string | undefined;
                            if (asmLine['func-name'] && asmLine.offset) {
                                funcAndOffset = `${asmLine['func-name']}+${asmLine.offset}`;
                            } else if (asmLine['func-name']) {
                                funcAndOffset = asmLine['func-name'];
                            } else {
                                funcAndOffset = undefined;
                            }
                            const disInsn = {
                                address: asmLine.address,
                                instructionBytes: asmLine.opcodes,
                                instruction: asmLine.inst,
                                symbol: funcAndOffset,
                                location: source,
                                line,
                            } as DebugProtocol.DisassembledInstruction;
                            instructions.push(disInsn);
                            if (instructions.length === args.instructionCount) {
                                break outer_loop;
                            }

                            const bytes = asmLine.opcodes.replace(/\s/g, '');
                            startOffset += bytes.length;
                        }
                    }
                } catch (err) {
                    // Failed to read instruction -- what best to do here?
                    // in other words, whose responsibility (adapter or client)
                    // to reissue reads in smaller chunks to find good memory
                    while (instructions.length < args.instructionCount) {
                        const badDisInsn = {
                            // TODO this should start at byte after last retrieved address
                            address: `0x${startOffset.toString(16)}`,
                            instruction:
                                err instanceof Error
                                    ? err.message
                                    : String(err),
                        } as DebugProtocol.DisassembledInstruction;
                        instructions.push(badDisInsn);
                        startOffset += 2;
                    }
                    break outer_loop;
                }
            }

            if (!args.endMemoryReference) {
                while (instructions.length < args.instructionCount) {
                    const badDisInsn = {
                        // TODO this should start at byte after last retrieved address
                        address: `0x${startOffset.toString(16)}`,
                        instruction: 'failed to retrieve instruction',
                    } as DebugProtocol.DisassembledInstruction;
                    instructions.push(badDisInsn);
                    startOffset += 2;
                }
            }

            response.body = { instructions };
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async readMemoryRequest(
        response: DebugProtocol.ReadMemoryResponse,
        args: DebugProtocol.ReadMemoryArguments
    ): Promise<void> {
        try {
            if (args.count) {
                const result = await sendDataReadMemoryBytes(
                    this.gdb,
                    args.memoryReference,
                    args.count,
                    args.offset
                );
                response.body = {
                    data: hexToBase64(result.memory[0].contents),
                    address: result.memory[0].begin,
                };
                this.sendResponse(response);
            } else {
                this.sendResponse(response);
            }
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    /**
     * Implement the memoryWrite request.
     */
    protected async writeMemoryRequest(
        response: DebugProtocol.WriteMemoryResponse,
        args: DebugProtocol.WriteMemoryArguments
    ) {
        try {
            const { memoryReference, data } = args;
            const typeofAddress = typeof memoryReference;
            const typeofContent = typeof data;
            if (typeofAddress !== 'string') {
                throw new Error(
                    `Invalid type for 'address', expected string, got ${typeofAddress}`
                );
            }
            if (typeofContent !== 'string') {
                throw new Error(
                    `Invalid type for 'content', expected string, got ${typeofContent}`
                );
            }
            const hexContent = base64ToHex(data);
            await sendDataWriteMemoryBytes(
                this.gdb,
                memoryReference,
                hexContent
            );
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected async disconnectRequest(
        response: DebugProtocol.DisconnectResponse,
        _args: DebugProtocol.DisconnectArguments
    ): Promise<void> {
        try {
            await this.gdb.sendGDBExit();
            this.sendResponse(response);
        } catch (err) {
            this.sendErrorResponse(
                response,
                1,
                err instanceof Error ? err.message : String(err)
            );
        }
    }

    protected sendStoppedEvent(
        reason: string,
        threadId: number,
        allThreadsStopped?: boolean
    ) {
        // Reset frame handles and variables for new context
        this.frameHandles.reset();
        this.variableHandles.reset();
        // Send the event
        this.sendEvent(new StoppedEvent(reason, threadId, allThreadsStopped));
    }

    protected handleGDBStopped(result: any) {
        const getThreadId = (resultData: any) =>
            parseInt(resultData['thread-id'], 10);
        const getAllThreadsStopped = (resultData: any) => {
            return (
                !!resultData['stopped-threads'] &&
                resultData['stopped-threads'] === 'all'
            );
        };

        switch (result.reason) {
            case 'exited':
            case 'exited-normally':
                this.sendEvent(new TerminatedEvent());
                break;
            case 'breakpoint-hit':
                if (this.logPointMessages[result.bkptno]) {
                    this.sendEvent(
                        new OutputEvent(this.logPointMessages[result.bkptno])
                    );
                    mi.sendExecContinue(this.gdb);
                } else {
                    const reason =
                        this.functionBreakpoints.indexOf(result.bkptno) > -1
                            ? 'function breakpoint'
                            : 'breakpoint';
                    this.sendStoppedEvent(
                        reason,
                        getThreadId(result),
                        getAllThreadsStopped(result)
                    );
                }
                break;
            case 'end-stepping-range':
            case 'function-finished':
                this.sendStoppedEvent(
                    'step',
                    getThreadId(result),
                    getAllThreadsStopped(result)
                );
                break;
            case 'signal-received': {
                const name = result['signal-name'] || 'signal';
                this.sendStoppedEvent(
                    name,
                    getThreadId(result),
                    getAllThreadsStopped(result)
                );
                if (this.waitPaused) {
                    this.waitPaused();
                }
                break;
            }
            default:
                this.sendStoppedEvent(
                    'generic',
                    getThreadId(result),
                    getAllThreadsStopped(result)
                );
        }
    }

    protected handleGDBAsync(resultClass: string, resultData: any) {
        const updateIsRunning = () => {
            this.isRunning = true;
            for (const thread of this.threads) {
                if (!thread.running) {
                    this.isRunning = false;
                }
            }
        };
        switch (resultClass) {
            case 'running':
                if (this.gdb.isNonStopMode()) {
                    const id = parseInt(resultData.thread_id, 10);
                    for (const thread of this.threads) {
                        if (thread.id === id) {
                            thread.running = true;
                        }
                    }
                } else {
                    for (const thread of this.threads) {
                        thread.running = true;
                    }
                }
                updateIsRunning();
                break;
            case 'stopped': {
                if (this.gdb.isNonStopMode()) {
                    const id = parseInt(resultData.thread_id, 10);
                    for (const thread of this.threads) {
                        if (thread.id === id) {
                            thread.running = false;
                        }
                    }
                } else {
                    for (const thread of this.threads) {
                        thread.running = false;
                    }
                }
                const wasRunning = this.isRunning;
                updateIsRunning();
                if (
                    this.gdb.isNonStopMode() ||
                    (wasRunning && !this.isRunning)
                ) {
                    if (this.isInitialized) {
                        this.handleGDBStopped(resultData);
                    }
                }
                break;
            }
            default:
                logger.warn(
                    `GDB unhandled async: ${resultClass}: ${JSON.stringify(
                        resultData
                    )}`
                );
        }
    }

    protected handleGDBNotify(notifyClass: string, notifyData: any) {
        switch (notifyClass) {
            case 'thread-created':
                this.threads.push(this.convertThread(notifyData));
                break;
            case 'thread-exited': {
                const thread: mi.MIThreadInfo = notifyData;
                const exitId = parseInt(thread.id, 10);
                this.threads = this.threads.filter((t) => t.id !== exitId);
                break;
            }
            case 'thread-selected':
            case 'thread-group-added':
            case 'thread-group-started':
            case 'thread-group-exited':
            case 'library-loaded':
            case 'breakpoint-modified':
            case 'breakpoint-deleted':
                // Known unhandled notifies
                break;
            default:
                logger.warn(
                    `GDB unhandled notify: ${notifyClass}: ${JSON.stringify(
                        notifyData
                    )}`
                );
        }
    }

    protected async handleVariableRequestFrame(
        ref: FrameVariableReference
    ): Promise<DebugProtocol.Variable[]> {
        // initialize variables array and dereference the frame handle
        const variables: DebugProtocol.Variable[] = [];
        const frame = this.frameHandles.get(ref.frameHandle);
        if (!frame) {
            return Promise.resolve(variables);
        }

        // vars used to determine if we should call sendStackListVariables()
        let callStack = false;
        let numVars = 0;

        // stack depth necessary for differentiating between similarly named variables at different stack depths
        const stackDepth = await mi.sendStackInfoDepth(this.gdb, {
            maxDepth: 100,
        });
        const depth = parseInt(stackDepth.depth, 10);

        // array of varnames to delete. Cannot delete while iterating through the vars array below.
        const toDelete = new Array<string>();

        // get the list of vars we need to update for this frameId/threadId/depth tuple
        const vars = this.gdb.varManager.getVars(
            frame.frameId,
            frame.threadId,
            depth
        );
        if (vars) {
            for (const varobj of vars) {
                // ignore expressions and child entries
                if (varobj.isVar && !varobj.isChild) {
                    // request update from GDB
                    const vup = await mi.sendVarUpdate(this.gdb, {
                        name: varobj.varname,
                    });
                    // if changelist is length 0, update is undefined
                    const update = vup.changelist[0];
                    let pushVar = true;
                    if (update) {
                        if (update.in_scope === 'true') {
                            numVars++;
                            if (update.name === varobj.varname) {
                                // don't update the parent value to a child's value
                                varobj.value = update.value;
                            }
                        } else {
                            // var is out of scope, delete it and call sendStackListVariables() later
                            callStack = true;
                            pushVar = false;
                            toDelete.push(update.name);
                        }
                    } else if (varobj.value) {
                        // value hasn't updated but it's still in scope
                        numVars++;
                    }
                    // only push entries to the result that aren't being deleted
                    if (pushVar) {
                        let value = varobj.value;
                        // if we have an array parent entry, we need to display the address.
                        if (arrayRegex.test(varobj.type)) {
                            value = await this.getAddr(varobj);
                        }
                        variables.push({
                            name: varobj.expression,
                            value,
                            type: varobj.type,
                            memoryReference: `&(${varobj.expression})`,
                            variablesReference:
                                parseInt(varobj.numchild, 10) > 0
                                    ? this.variableHandles.create({
                                          type: 'object',
                                          frameHandle: ref.frameHandle,
                                          varobjName: varobj.varname,
                                      })
                                    : 0,
                        });
                    }
                }
            }
            // clean up out of scope entries
            for (const varname of toDelete) {
                await this.gdb.varManager.removeVar(
                    frame.frameId,
                    frame.threadId,
                    depth,
                    varname
                );
            }
        }
        // if we had out of scope entries or no entries in the frameId/threadId/depth tuple, query GDB for new ones
        if (callStack === true || numVars === 0) {
            const result = await mi.sendStackListVariables(this.gdb, {
                thread: frame.threadId,
                frame: frame.frameId,
                printValues: 'simple-values',
            });
            for (const variable of result.variables) {
                let varobj = this.gdb.varManager.getVar(
                    frame.frameId,
                    frame.threadId,
                    depth,
                    variable.name
                );
                if (!varobj) {
                    // create var in GDB and store it in the varMgr
                    const varCreateResponse = await mi.sendVarCreate(this.gdb, {
                        expression: variable.name,
                        frameId: frame.frameId,
                        threadId: frame.threadId,
                    });
                    varobj = this.gdb.varManager.addVar(
                        frame.frameId,
                        frame.threadId,
                        depth,
                        variable.name,
                        true,
                        false,
                        varCreateResponse
                    );
                } else {
                    // var existed as an expression before. Now it's a variable too.
                    varobj = await this.gdb.varManager.updateVar(
                        frame.frameId,
                        frame.threadId,
                        depth,
                        varobj
                    );
                    varobj.isVar = true;
                }
                let value = varobj.value;
                // if we have an array parent entry, we need to display the address.
                if (arrayRegex.test(varobj.type)) {
                    value = await this.getAddr(varobj);
                }
                variables.push({
                    name: varobj.expression,
                    value,
                    type: varobj.type,
                    memoryReference: `&(${varobj.expression})`,
                    variablesReference:
                        parseInt(varobj.numchild, 10) > 0
                            ? this.variableHandles.create({
                                  type: 'object',
                                  frameHandle: ref.frameHandle,
                                  varobjName: varobj.varname,
                              })
                            : 0,
                });
            }
        }
        return Promise.resolve(variables);
    }

    protected async handleVariableRequestObject(
        ref: ObjectVariableReference
    ): Promise<DebugProtocol.Variable[]> {
        // initialize variables array and dereference the frame handle
        const variables: DebugProtocol.Variable[] = [];
        const frame = this.frameHandles.get(ref.frameHandle);
        if (!frame) {
            return Promise.resolve(variables);
        }

        // fetch stack depth to obtain frameId/threadId/depth tuple
        const stackDepth = await mi.sendStackInfoDepth(this.gdb, {
            maxDepth: 100,
        });
        const depth = parseInt(stackDepth.depth, 10);
        // we need to keep track of children and the parent varname in GDB
        let children;
        let parentVarname = ref.varobjName;

        // if a varobj exists, use the varname stored there
        const varobj = this.gdb.varManager.getVarByName(
            frame.frameId,
            frame.threadId,
            depth,
            ref.varobjName
        );
        if (varobj) {
            children = await mi.sendVarListChildren(this.gdb, {
                name: varobj.varname,
                printValues: mi.MIVarPrintValues.all,
            });
            parentVarname = varobj.varname;
        } else {
            // otherwise use the parent name passed in the variable reference
            children = await mi.sendVarListChildren(this.gdb, {
                name: ref.varobjName,
                printValues: mi.MIVarPrintValues.all,
            });
        }

        // iterate through the children
        for (const child of children.children) {
            // check if we're dealing with a C++ object. If we are, we need to fetch the grandchildren instead.
            const isClass = this.isChildOfClass(child);
            if (isClass) {
                const name = `${parentVarname}.${child.exp}`;
                const objChildren = await mi.sendVarListChildren(this.gdb, {
                    name,
                    printValues: mi.MIVarPrintValues.all,
                });
                for (const objChild of objChildren.children) {
                    const childName = `${name}.${objChild.exp}`;
                    variables.push({
                        name: objChild.exp,
                        value: objChild.value ? objChild.value : objChild.type,
                        type: objChild.type,
                        variablesReference:
                            parseInt(objChild.numchild, 10) > 0
                                ? this.variableHandles.create({
                                      type: 'object',
                                      frameHandle: ref.frameHandle,
                                      varobjName: childName,
                                  })
                                : 0,
                    });
                }
            } else {
                // check if we're dealing with an array
                let name = `${ref.varobjName}.${child.exp}`;
                let varobjName = name;
                let value = child.value ? child.value : child.type;
                const isArrayParent = arrayRegex.test(child.type);
                const isArrayChild =
                    varobj !== undefined
                        ? arrayRegex.test(varobj.type) &&
                          arrayChildRegex.test(child.exp)
                        : false;
                if (isArrayChild) {
                    // update the display name for array elements to have square brackets
                    name = `[${child.exp}]`;
                }
                if (isArrayParent || isArrayChild) {
                    // can't use a relative varname (eg. var1.a.b.c) to create/update a new var so fetch and track these
                    // vars by evaluating their path expression from GDB
                    const exprResponse = await mi.sendVarInfoPathExpression(
                        this.gdb,
                        child.name
                    );
                    // create or update the var in GDB
                    let arrobj = this.gdb.varManager.getVar(
                        frame.frameId,
                        frame.threadId,
                        depth,
                        exprResponse.path_expr
                    );
                    if (!arrobj) {
                        const varCreateResponse = await mi.sendVarCreate(
                            this.gdb,
                            {
                                expression: exprResponse.path_expr,
                                frameId: frame.frameId,
                                threadId: frame.threadId,
                            }
                        );
                        arrobj = this.gdb.varManager.addVar(
                            frame.frameId,
                            frame.threadId,
                            depth,
                            exprResponse.path_expr,
                            true,
                            false,
                            varCreateResponse
                        );
                    } else {
                        arrobj = await this.gdb.varManager.updateVar(
                            frame.frameId,
                            frame.threadId,
                            depth,
                            arrobj
                        );
                    }
                    // if we have an array parent entry, we need to display the address.
                    if (isArrayParent) {
                        value = await this.getAddr(arrobj);
                    }
                    arrobj.isChild = true;
                    varobjName = arrobj.varname;
                }
                const variableName = isArrayChild ? name : child.exp;
                variables.push({
                    name: variableName,
                    value,
                    type: child.type,
                    variablesReference:
                        parseInt(child.numchild, 10) > 0
                            ? this.variableHandles.create({
                                  type: 'object',
                                  frameHandle: ref.frameHandle,
                                  varobjName,
                              })
                            : 0,
                });
            }
        }
        return Promise.resolve(variables);
    }

    // Register view
    // Assume that the register name are unchanging over time, and the same across all threadsf
    private registerMap = new Map<string, number>();
    private registerMapReverse = new Map<number, string>();
    protected async handleVariableRequestRegister(
        ref: RegisterVariableReference
    ): Promise<DebugProtocol.Variable[]> {
        // initialize variables array and dereference the frame handle
        const variables: DebugProtocol.Variable[] = [];
        const frame = this.frameHandles.get(ref.frameHandle);
        if (!frame) {
            return Promise.resolve(variables);
        }

        if (this.registerMap.size === 0) {
            const result_names = await mi.sendDataListRegisterNames(this.gdb, {
                frameId: frame.frameId,
                threadId: frame.threadId,
            });
            let idx = 0;
            const registerNames = result_names['register-names'];
            for (const regs of registerNames) {
                if (regs !== '') {
                    this.registerMap.set(regs, idx);
                    this.registerMapReverse.set(idx, regs);
                }
                idx++;
            }
        }

        const result_values = await mi.sendDataListRegisterValues(this.gdb, {
            fmt: 'x',
            frameId: frame.frameId,
            threadId: frame.threadId,
        });
        const reg_values = result_values['register-values'];
        for (const n of reg_values) {
            const id = n.number;
            const reg = this.registerMapReverse.get(parseInt(id));
            if (reg) {
                const val = n.value;
                const res: DebugProtocol.Variable = {
                    name: reg,
                    evaluateName: '$' + reg,
                    value: val,
                    variablesReference: 0,
                };
                variables.push(res);
            } else {
                throw new Error('Unable to parse response for reg. values');
            }
        }

        return Promise.resolve(variables);
    }

    protected async getAddr(varobj: VarObjType) {
        const addr = await mi.sendDataEvaluateExpression(
            this.gdb,
            `&(${varobj.expression})`
        );
        return addr.value ? addr.value : varobj.value;
    }

    protected isChildOfClass(child: mi.MIVarChild): boolean {
        return (
            child.type === undefined &&
            child.value === '' &&
            (child.exp === 'public' ||
                child.exp === 'protected' ||
                child.exp === 'private')
        );
    }
}