service/dap: Initial implementation for 'dlv dap' (#1858)

* Initial implementation for 'dlv dap'

* Fix Travis and AppVeyor failures

* Address review comments

* Address review comments

* Regenrate documentation

* Replace dap server printfs with log.Error

* Update 'dap log'

* Fix typos

* Revert logflags changes that got mixed in by accident

Documentation/usage/dlv.md

@@ -38,6 +38,7 @@ Pass flags to the program you are debugging using `--`, for example:
 * [dlv attach](dlv_attach.md)	 - Attach to running process and begin debugging.
 * [dlv connect](dlv_connect.md)	 - Connect to a headless debug server.
 * [dlv core](dlv_core.md)	 - Examine a core dump.
+* [dlv dap](dlv_dap.md)	 - [EXPERIMENTAL] Starts a TCP server communicating via Debug Adaptor Protocol (DAP).
 * [dlv debug](dlv_debug.md)	 - Compile and begin debugging main package in current directory, or the package specified.
 * [dlv exec](dlv_exec.md)	 - Execute a precompiled binary, and begin a debug session.
 * [dlv replay](dlv_replay.md)	 - Replays a rr trace.

Documentation/usage/dlv_dap.md

@@ -0,0 +1,41 @@
+## dlv dap
+
+[EXPERIMENTAL] Starts a TCP server communicating via Debug Adaptor Protocol (DAP).
+
+### Synopsis
+
+
+[EXPERIMENTAL] Starts a TCP server communicating via Debug Adaptor Protocol (DAP).
+
+The server supports debugging of a precompiled binary akin to 'dlv exec' via a launch request.
+It does not yet support support specification of program arguments.
+It does not yet support launch requests with 'debug' and 'test' modes that require compilation.
+It does not yet support attach requests to debug a running process like with 'dlv attach'.
+It does not yet support asynchronous request-response communication.
+The server does not accept multiple client connections.
+
+```
+dlv dap
+```
+
+### Options inherited from parent commands
+
+```
+      --accept-multiclient   Allows a headless server to accept multiple client connections.
+      --api-version int      Selects API version when headless. (default 1)
+      --backend string       Backend selection (see 'dlv help backend'). (default "default")
+      --build-flags string   Build flags, to be passed to the compiler.
+      --check-go-version     Checks that the version of Go in use is compatible with Delve. (default true)
+      --headless             Run debug server only, in headless mode.
+      --init string          Init file, executed by the terminal client.
+  -l, --listen string        Debugging server listen address. (default "127.0.0.1:0")
+      --log                  Enable debugging server logging.
+      --log-dest string      Writes logs to the specified file or file descriptor (see 'dlv help log').
+      --log-output string    Comma separated list of components that should produce debug output (see 'dlv help log')
+      --only-same-user       Only connections from the same user that started this instance of Delve are allowed to connect. (default true)
+      --wd string            Working directory for running the program. (default ".")
+```
+
+### SEE ALSO
+* [dlv](dlv.md)	 - Delve is a debugger for the Go programming language.
+

Documentation/usage/dlv_log.md

@@ -17,6 +17,7 @@ names selected from this list:
 	lldbout		Copy output from debugserver/lldb to standard output
 	debuglineerr	Log recoverable errors reading .debug_line
 	rpc		Log all RPC messages
+	dap		Log all DAP messages
 	fncall		Log function call protocol
 	minidump	Log minidump loading
 
@@ -24,8 +25,8 @@ Additionally --log-dest can be used to specify where the logs should be
 written. 
 If the argument is a number it will be interpreted as a file descriptor,
 otherwise as a file path.
-This option will also redirect the \"API listening\" message in headless
-mode.
+This option will also redirect the "server listening at" message in headless
+and dap modes.
 
 
 

cmd/dlv/cmds/commands.go

@@ -19,6 +19,7 @@ import (
 	"github.com/go-delve/delve/pkg/version"
 	"github.com/go-delve/delve/service"
 	"github.com/go-delve/delve/service/api"
+	"github.com/go-delve/delve/service/dap"
 	"github.com/go-delve/delve/service/rpc2"
 	"github.com/go-delve/delve/service/rpccommon"
 	"github.com/spf13/cobra"
@@ -152,6 +153,22 @@ option to let the process continue or kill it.
 	}
 	RootCommand.AddCommand(connectCommand)
 
+	// 'dap' subcommand.
+	dapCommand := &cobra.Command{
+		Use:   "dap",
+		Short: "[EXPERIMENTAL] Starts a TCP server communicating via Debug Adaptor Protocol (DAP).",
+		Long: `[EXPERIMENTAL] Starts a TCP server communicating via Debug Adaptor Protocol (DAP).
+
+The server supports debugging of a precompiled binary akin to 'dlv exec' via a launch request.
+It does not yet support support specification of program arguments.
+It does not yet support launch requests with 'debug' and 'test' modes that require compilation.
+It does not yet support attach requests to debug a running process like with 'dlv attach'.
+It does not yet support asynchronous request-response communication.
+The server does not accept multiple client connections.`,
+		Run: dapCmd,
+	}
+	RootCommand.AddCommand(dapCommand)
+
 	// 'debug' subcommand.
 	debugCommand := &cobra.Command{
 		Use:   "debug [package]",
@@ -318,6 +335,7 @@ names selected from this list:
 	lldbout		Copy output from debugserver/lldb to standard output
 	debuglineerr	Log recoverable errors reading .debug_line
 	rpc		Log all RPC messages
+	dap		Log all DAP messages
 	fncall		Log function call protocol
 	minidump	Log minidump loading
 
@@ -325,8 +343,8 @@ Additionally --log-dest can be used to specify where the logs should be
 written. 
 If the argument is a number it will be interpreted as a file descriptor,
 otherwise as a file path.
-This option will also redirect the \"API listening\" message in headless
-mode.
+This option will also redirect the "server listening at" message in headless
+and dap modes.
 
 `,
 	})
@@ -344,6 +362,63 @@ func remove(path string) {
 	}
 }
 
+func dapCmd(cmd *cobra.Command, args []string) {
+	status := func() int {
+		if err := logflags.Setup(Log, LogOutput, LogDest); err != nil {
+			fmt.Fprintf(os.Stderr, "%v\n", err)
+			return 1
+		}
+		defer logflags.Close()
+
+		if Headless {
+			fmt.Fprintf(os.Stderr, "Warning: headless mode not supported with dap\n")
+		}
+		if AcceptMulti {
+			fmt.Fprintf(os.Stderr, "Warning: accept multiclient mode not supported with dap\n")
+		}
+		if InitFile != "" {
+			fmt.Fprint(os.Stderr, "Warning: init file ignored with dap\n")
+		}
+		if ContinueOnStart {
+			fmt.Fprintf(os.Stderr, "Warning: continue ignored with dap; specify via launch/attach request instead\n")
+		}
+		if BuildFlags != "" {
+			fmt.Fprintf(os.Stderr, "Warning: build flags ignored with dap; specify via launch/attach request instead\n")
+		}
+		if WorkingDir != "" {
+			fmt.Fprintf(os.Stderr, "Warning: working directory ignored with dap; launch requests must specify full program path\n")
+		}
+		dlvArgs, targetArgs := splitArgs(cmd, args)
+		if len(dlvArgs) > 0 {
+			fmt.Fprintf(os.Stderr, "Warning: debug arguments ignored with dap; specify via launch/attach request instead\n")
+		}
+		if len(targetArgs) > 0 {
+			fmt.Fprintf(os.Stderr, "Warning: program flags ignored with dap; specify via launch/attach request instead\n")
+		}
+
+		listener, err := net.Listen("tcp", Addr)
+		if err != nil {
+			fmt.Printf("couldn't start listener: %s\n", err)
+			return 1
+		}
+		disconnectChan := make(chan struct{})
+		server := dap.NewServer(&service.Config{
+			Listener:             listener,
+			Backend:              Backend,
+			Foreground:           true, // always headless
+			DebugInfoDirectories: conf.DebugInfoDirectories,
+			CheckGoVersion:       CheckGoVersion,
+			DisconnectChan:       disconnectChan,
+		})
+		defer server.Stop()
+
+		server.Run()
+		waitForDisconnectSignal(disconnectChan)
+		return 0
+	}()
+	os.Exit(status)
+}
+
 func debugCmd(cmd *cobra.Command, args []string) {
 	status := func() int {
 		debugname, err := filepath.Abs(cmd.Flag("output").Value.String())
@@ -535,6 +610,37 @@ func connectCmd(cmd *cobra.Command, args []string) {
 	os.Exit(connect(addr, nil, conf, executingOther))
 }
 
+// waitForDisconnectSignal is a blocking function that waits for either
+// a SIGINT (Ctrl-C) signal from the OS or for disconnectChan to be closed
+// by the server when the client disconnects.
+// Note that in headless mode, the debugged process is foregrounded
+// (to have control of the tty for debugging interactive programs),
+// so SIGINT gets sent to the debuggee and not to delve.
+func waitForDisconnectSignal(disconnectChan chan struct{}) {
+	ch := make(chan os.Signal, 1)
+	signal.Notify(ch, syscall.SIGINT)
+	if runtime.GOOS == "windows" {
+		// On windows Ctrl-C sent to inferior process is delivered
+		// as SIGINT to delve. Ignore it instead of stopping the server
+		// in order to be able to debug signal handlers.
+		go func() {
+			for {
+				select {
+				case <-ch:
+				}
+			}
+		}()
+		select {
+		case <-disconnectChan:
+		}
+	} else {
+		select {
+		case <-ch:
+		case <-disconnectChan:
+		}
+	}
+}
+
 func splitArgs(cmd *cobra.Command, args []string) ([]string, []string) {
 	if cmd.ArgsLenAtDash() >= 0 {
 		return args[:cmd.ArgsLenAtDash()], args[cmd.ArgsLenAtDash():]
@@ -678,28 +784,7 @@ func execute(attachPid int, processArgs []string, conf *config.Config, coreFile
 			client = rpc2.NewClient(listener.Addr().String())
 			client.Disconnect(true) // true = continue after disconnect
 		}
-		ch := make(chan os.Signal, 1)
-		signal.Notify(ch, syscall.SIGINT)
-		if runtime.GOOS == "windows" {
-			// On windows Ctrl-C sent to inferior process is delivered
-			// as SIGINT to delve. Ignore it instead of stopping the server
-			// in order to be able to debug signal handlers.
-			go func() {
-				for {
-					select {
-					case <-ch:
-					}
-				}
-			}()
-			select {
-			case <-disconnectChan:
-			}
-		} else {
-			select {
-			case <-ch:
-			case <-disconnectChan:
-			}
-		}
+		waitForDisconnectSignal(disconnectChan)
 		err = server.Stop()
 		if err != nil {
 			fmt.Println(err)

go.mod

@@ -5,6 +5,7 @@ go 1.11
 require (
 	github.com/cosiner/argv v0.0.0-20170225145430-13bacc38a0a5
 	github.com/cpuguy83/go-md2man v1.0.8 // indirect
+	github.com/google/go-dap v0.1.0
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/mattn/go-colorable v0.0.0-20170327083344-ded68f7a9561

go.sum

@@ -8,6 +8,8 @@ github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/go-dap v0.1.0 h1:UzVzngq6yBR+bJVnTM8mjcdKrQnYR7m7U7JpNSnEo48=
+github.com/google/go-dap v0.1.0/go.mod h1:5q8aYQFnHOAZEMP+6vmq25HKYAEwE+LF5yh7JKrrhSQ=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=

pkg/logflags/logflags.go

@@ -21,6 +21,7 @@ var gdbWire = false
 var lldbServerOutput = false
 var debugLineErrors = false
 var rpc = false
+var dap = false
 var fnCall = false
 var minidump = false
 
@@ -82,6 +83,16 @@ func RPCLogger() *logrus.Entry {
 	return makeLogger(rpc, logrus.Fields{"layer": "rpc"})
 }
 
+// DAP returns true if dap package should log.
+func DAP() bool {
+	return dap
+}
+
+// DAPLogger returns a logger for dap package.
+func DAPLogger() *logrus.Entry {
+	return makeLogger(dap, logrus.Fields{"layer": "dap"})
+}
+
 // FnCall returns true if the function call protocol should be logged.
 func FnCall() bool {
 	return fnCall
@@ -100,12 +111,21 @@ func MinidumpLogger() *logrus.Entry {
 	return makeLogger(minidump, logrus.Fields{"layer": "core", "kind": "minidump"})
 }
 
+// WriteDAPListeningMessage writes the "DAP server listening" message in dap mode.
+func WriteDAPListeningMessage(addr string) {
+	writeListeningMessage("DAP", addr)
+}
+
 // WriteAPIListeningMessage writes the "API server listening" message in headless mode.
 func WriteAPIListeningMessage(addr string) {
+	writeListeningMessage("API", addr)
+}
+
+func writeListeningMessage(server string, addr string) {
 	if logOut != nil {
-		fmt.Fprintf(logOut, "API server listening at: %s\n", addr)
+		fmt.Fprintf(logOut, "%s server listening at: %s\n", server, addr)
 	} else {
-		fmt.Printf("API server listening at: %s\n", addr)
+		fmt.Printf("%s server listening at: %s\n", server, addr)
 	}
 }
 
@@ -151,10 +171,14 @@ func Setup(logFlag bool, logstr string, logDest string) error {
 			debugLineErrors = true
 		case "rpc":
 			rpc = true
+		case "dap":
+			dap = true
 		case "fncall":
 			fnCall = true
 		case "minidump":
 			minidump = true
+			// If adding another value, do make sure to
+			// update "Help about logging flags" in commands.go.
 		}
 	}
 	return nil

service/dap/daptest/client.go

@@ -0,0 +1,189 @@
+package daptest
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"path/filepath"
+
+	"github.com/google/go-dap"
+)
+
+// Package daptest provides a sample client with utilities
+// for DAP mode testing.
+
+// Client is a debugger service client that uses Debug Adaptor Protocol.
+// It does not (yet?) implement service.Client interface.
+// All client methods are synchronous.
+type Client struct {
+	conn   net.Conn
+	reader *bufio.Reader
+	// seq is used to track the sequence number of each
+	// requests that the client sends to the server
+	seq int
+}
+
+// NewClient creates a new Client over a TCP connection.
+// Call Close() to close the connection.
+func NewClient(addr string) *Client {
+	fmt.Println("Connecting to server at:", addr)
+	conn, err := net.Dial("tcp", addr)
+	if err != nil {
+		log.Fatal("dialing:", err)
+	}
+	c := &Client{conn: conn, reader: bufio.NewReader(conn)}
+	return c
+}
+
+// Close closes the client connection
+func (c *Client) Close() {
+	c.conn.Close()
+}
+
+func (c *Client) send(request dap.Message) {
+	jsonmsg, _ := json.Marshal(request)
+	fmt.Println("[client -> server]", string(jsonmsg))
+	dap.WriteProtocolMessage(c.conn, request)
+}
+
+// ReadBaseMessage reads and returns a json-encoded DAP message.
+func (c *Client) ReadBaseMessage() ([]byte, error) {
+	message, err := dap.ReadBaseMessage(c.reader)
+	if err != nil {
+		fmt.Println("DAP client error:", err)
+		return nil, err
+	}
+	fmt.Println("[client <- server]", string(message))
+	return message, nil
+}
+
+// ReadErrorResponse reads, decodes and validates the result
+// to be an error response. Returns the response or an error.
+func (c *Client) ReadErrorResponse() (dap.Message, error) {
+	response, err := dap.ReadProtocolMessage(c.reader)
+	if err != nil {
+		return nil, err
+	}
+	switch response.(type) {
+	case *dap.ErrorResponse:
+		return response, nil
+	default:
+		return nil, errors.New(fmt.Sprintf("not an ErrorResponse: %#v", response))
+	}
+}
+
+// InitializeRequest sends an 'initialize' request.
+func (c *Client) InitializeRequest() {
+	request := &dap.InitializeRequest{Request: *c.newRequest("initialize")}
+	request.Arguments = dap.InitializeRequestArguments{
+		AdapterID:                    "go",
+		PathFormat:                   "path",
+		LinesStartAt1:                true,
+		ColumnsStartAt1:              true,
+		SupportsVariableType:         true,
+		SupportsVariablePaging:       true,
+		SupportsRunInTerminalRequest: true,
+		Locale:                       "en-us",
+	}
+	c.send(request)
+}
+
+// LaunchRequest sends a 'launch' request.
+func (c *Client) LaunchRequest(program string, stopOnEntry bool) {
+	request := &dap.LaunchRequest{Request: *c.newRequest("launch")}
+	request.Arguments = map[string]interface{}{
+		"request":     "launch",
+		"mode":        "exec",
+		"program":     program,
+		"stopOnEntry": stopOnEntry,
+	}
+	c.send(request)
+}
+
+// DisconnectRequest sends a 'disconnect' request.
+func (c *Client) DisconnectRequest() {
+	request := &dap.DisconnectRequest{Request: *c.newRequest("disconnect")}
+	c.send(request)
+}
+
+// SetBreakpointsRequest sends a 'setBreakpoints' request.
+func (c *Client) SetBreakpointsRequest(file string, lines []int) {
+	request := &dap.SetBreakpointsRequest{Request: *c.newRequest("setBreakpoints")}
+	request.Arguments = dap.SetBreakpointsArguments{
+		Source: dap.Source{
+			Name: filepath.Base(file),
+			Path: file,
+		},
+		Breakpoints: make([]dap.SourceBreakpoint, len(lines)),
+		//sourceModified: false,
+	}
+	for i, l := range lines {
+		request.Arguments.Breakpoints[i].Line = l
+	}
+	c.send(request)
+}
+
+// SetExceptionBreakpointsRequest sends a 'setExceptionBreakpoints' request.
+func (c *Client) SetExceptionBreakpointsRequest() {
+	request := &dap.SetBreakpointsRequest{Request: *c.newRequest("setExceptionBreakpoints")}
+	c.send(request)
+}
+
+// ConfigurationDoneRequest sends a 'configurationDone' request.
+func (c *Client) ConfigurationDoneRequest() {
+	request := &dap.ConfigurationDoneRequest{Request: *c.newRequest("configurationDone")}
+	c.send(request)
+}
+
+// ContinueRequest sends a 'continue' request.
+func (c *Client) ContinueRequest(thread int) {
+	request := &dap.ContinueRequest{Request: *c.newRequest("continue")}
+	request.Arguments.ThreadId = thread
+	c.send(request)
+}
+
+// UnknownRequest triggers dap.DecodeProtocolMessageFieldError.
+func (c *Client) UnkownRequest() {
+	request := c.newRequest("unknown")
+	c.send(request)
+}
+
+// UnkownProtocolMessage triggers dap.DecodeProtocolMessageFieldError.
+func (c *Client) UnkownProtocolMessage() {
+	m := &dap.ProtocolMessage{}
+	m.Seq = -1
+	m.Type = "unknown"
+	c.send(m)
+}
+
+// UnknownEvent triggers dap.DecodeProtocolMessageFieldError.
+func (c *Client) UnknownEvent() {
+	event := &dap.Event{}
+	event.Type = "event"
+	event.Seq = -1
+	event.Event = "unknown"
+	c.send(event)
+}
+
+// KnownEvent passes decode checks, but delve has no 'case' to
+// handle it. This behaves the same way a new request type
+// added to go-dap, but not to delve.
+func (c *Client) KnownEvent() {
+	event := &dap.Event{}
+	event.Type = "event"
+	event.Seq = -1
+	event.Event = "terminated"
+	c.send(event)
+}
+
+func (c *Client) newRequest(command string) *dap.Request {
+	request := &dap.Request{}
+	request.Type = "request"
+	request.Command = command
+	request.Seq = c.seq
+	c.seq++
+	return request
+}

service/dap/error_ids.go

@@ -0,0 +1,15 @@
+package dap
+
+// Unique identifiers for messages returned for errors from requests.
+const (
+	UnsupportedCommand int = 9999
+
+	// The values below come from the vscode-go debug adaptor.
+	// Although the spec says they should be unique, the adaptor
+	// reuses 3000 for launch, attach and program exit failures.
+	// TODO(polina): confirm if the extension expects specific ids
+	// for specific cases, and we must match the existing adaptor
+	// or if these codes can evolve.
+	FailedToContinue = 3000
+	// Add more codes as we support more requests
+)

service/dap/server.go

@@ -0,0 +1,466 @@
+package dap
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"path/filepath"
+
+	"github.com/go-delve/delve/pkg/logflags"
+	"github.com/go-delve/delve/pkg/proc"
+	"github.com/go-delve/delve/service"
+	"github.com/go-delve/delve/service/api"
+	"github.com/go-delve/delve/service/debugger"
+	"github.com/google/go-dap"
+	"github.com/sirupsen/logrus"
+)
+
+// Package dap implements VSCode's Debug Adaptor Protocol (DAP).
+// This allows delve to communicate with frontends using DAP
+// without a separate adaptor. The frontend will run the debugger
+// (which now doubles as an adaptor) in server mode listening on
+// a port and communicating over TCP. This is work in progress,
+// so for now Delve in dap mode only supports synchronous
+// request-response communication, blocking while processing each request.
+// For DAP details see https://microsoft.github.io/debug-adapter-protocol.
+
+// Server implements a DAP server that can accept a single client for
+// a single debug session. It does not support restarting.
+// The server operates via two goroutines:
+// (1) Main goroutine where the server is created via NewServer(),
+// started via Run() and stopped via Stop().
+// (2) Run goroutine started from Run() that accepts a client connection,
+// reads, decodes and processes each request, issuing commands to the
+// underlying debugger and sending back events and responses.
+// TODO(polina): make it asynchronous (i.e. launch goroutine per request)
+type Server struct {
+	// config is all the information necessary to start the debugger and server.
+	config *service.Config
+	// listener is used to accept the client connection.
+	listener net.Listener
+	// conn is the accepted client connection.
+	conn net.Conn
+	// reader is used to read requests from the connection.
+	reader *bufio.Reader
+	// debugger is the underlying debugger service.
+	debugger *debugger.Debugger
+	// log is used for structured logging.
+	log *logrus.Entry
+	// stopOnEntry is set to automatically stop the debugee after start.
+	stopOnEntry bool
+}
+
+// NewServer creates a new DAP Server. It takes an opened Listener
+// via config and assumes its ownership. Optionally takes DisconnectChan
+// via config, which can be used to detect when the client disconnects
+// and the server is ready to be shut down. The caller must call
+// Stop() on shutdown.
+func NewServer(config *service.Config) *Server {
+	logger := logflags.DAPLogger()
+	logflags.WriteDAPListeningMessage(config.Listener.Addr().String())
+	return &Server{
+		config:   config,
+		listener: config.Listener,
+		log:      logger,
+	}
+}
+
+// Stop stops the DAP debugger service, closes the listener and
+// the client connection. It shuts down the underlying debugger
+// and kills the target process if it was launched by it.
+func (s *Server) Stop() {
+	s.listener.Close()
+	if s.conn != nil {
+		// Unless Stop() was called after serveDAPCodec()
+		// returned, this will result in closed connection error
+		// on next read, breaking out of the read loop and
+		// allowing the run goroutine to exit.
+		s.conn.Close()
+	}
+	if s.debugger != nil {
+		kill := s.config.AttachPid == 0
+		if err := s.debugger.Detach(kill); err != nil {
+			s.log.Error(err)
+		}
+	}
+}
+
+// signalDisconnect closes config.DisconnectChan if not nil, which
+// signals that the client disconnected or there was a client
+// connection failure. Since the server currently services only one
+// client, this can be used as a signal to the entire server via
+// Stop(). The function safeguards agaist closing the channel more
+// than once and can be called multiple times. It is not thread-safe
+// and is currently only called from the run goroutine.
+// TODO(polina): lock this when we add more goroutines that could call
+// this when we support asynchronous request-response communication.
+func (s *Server) signalDisconnect() {
+	// DisconnectChan might be nil at server creation if the
+	// caller does not want to rely on the disconnect signal.
+	if s.config.DisconnectChan != nil {
+		close(s.config.DisconnectChan)
+		// Take advantage of the nil check above to avoid accidentally
+		// closing the channel twice and causing a panic, when this
+		// function is called more than once. For example, we could
+		// have the following sequence of events:
+		// -- run goroutine: calls onDisconnectRequest()
+		// -- run goroutine: calls signalDisconnect()
+		// -- main goroutine: calls Stop()
+		// -- main goroutine: Stop() closes client connection
+		// -- run goroutine: serveDAPCodec() gets "closed network connection"
+		// -- run goroutine: serveDAPCodec() returns
+		// -- run goroutine: serveDAPCodec calls signalDisconnect()
+		s.config.DisconnectChan = nil
+	}
+}
+
+// Run launches a new goroutine where it accepts a client connection
+// and starts processing requests from it. Use Stop() to close connection.
+// The server does not support multiple clients, serially or in parallel.
+// The server should be restarted for every new debug session.
+// The debugger won't be started until launch/attach request is received.
+// TODO(polina): allow new client connections for new debug sessions,
+// so the editor needs to launch delve only once?
+func (s *Server) Run() {
+	go func() {
+		conn, err := s.listener.Accept()
+		if err != nil {
+			// This will print if the server is killed with Ctrl+C
+			// before client connection is accepted.
+			s.log.Errorf("Error accepting client connection: %s\n", err)
+			s.signalDisconnect()
+			return
+		}
+		s.conn = conn
+		s.serveDAPCodec()
+	}()
+}
+
+// serveDAPCodec reads and decodes requests from the client
+// until it encounters an error or EOF, when it sends
+// the disconnect signal and returns.
+func (s *Server) serveDAPCodec() {
+	defer s.signalDisconnect()
+	s.reader = bufio.NewReader(s.conn)
+	for {
+		request, err := dap.ReadProtocolMessage(s.reader)
+		// TODO(polina): Differentiate between errors and handle them
+		// gracefully. For example,
+		// -- "use of closed network connection" means client connection
+		// was closed via Stop() in response to a disconnect request.
+		// -- "Request command 'foo' is not supported" means we
+		// potentially got some new DAP request that we do not yet have
+		// decoding support for, so we can respond with an ErrorResponse.
+		// TODO(polina): to support this add Seq to
+		// dap.DecodeProtocolMessageFieldError.
+		if err != nil {
+			if err != io.EOF {
+				s.log.Error("DAP error: ", err)
+			}
+			return
+		}
+		// TODO(polina) Add a panic guard,
+		// so we do not kill user's process when delve panics.
+		s.handleRequest(request)
+	}
+}
+
+func (s *Server) handleRequest(request dap.Message) {
+	jsonmsg, _ := json.Marshal(request)
+	s.log.Debug("[<- from client]", string(jsonmsg))
+
+	switch request := request.(type) {
+	case *dap.InitializeRequest:
+		s.onInitializeRequest(request)
+	case *dap.LaunchRequest:
+		s.onLaunchRequest(request)
+	case *dap.AttachRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.DisconnectRequest:
+		s.onDisconnectRequest(request)
+	case *dap.TerminateRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.RestartRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.SetBreakpointsRequest:
+		s.onSetBreakpointsRequest(request)
+	case *dap.SetFunctionBreakpointsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.SetExceptionBreakpointsRequest:
+		s.onSetExceptionBreakpointsRequest(request)
+	case *dap.ConfigurationDoneRequest:
+		s.onConfigurationDoneRequest(request)
+	case *dap.ContinueRequest:
+		s.onContinueRequest(request)
+	case *dap.NextRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.StepInRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.StepOutRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.StepBackRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.ReverseContinueRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.RestartFrameRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.GotoRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.PauseRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.StackTraceRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.ScopesRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.VariablesRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.SetVariableRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.SetExpressionRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.SourceRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.ThreadsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.TerminateThreadsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.EvaluateRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.StepInTargetsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.GotoTargetsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.CompletionsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.ExceptionInfoRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.LoadedSourcesRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.DataBreakpointInfoRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.SetDataBreakpointsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.ReadMemoryRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.DisassembleRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.CancelRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	case *dap.BreakpointLocationsRequest:
+		s.sendUnsupportedErrorResponse(request.Request)
+	default:
+		// This is a DAP message that go-dap has a struct for, so
+		// decoding succeeded, but this function does not know how
+		// to handle. We should be sending an ErrorResponse, but
+		// we cannot get to Seq and other fields from dap.Message.
+		// TODO(polina): figure out how to handle this better.
+		// Consider adding GetSeq() method to dap.Message interface.
+		s.log.Errorf("Unable to process %#v\n", request)
+	}
+}
+
+func (s *Server) send(message dap.Message) {
+	jsonmsg, _ := json.Marshal(message)
+	s.log.Debug("[-> to client]", string(jsonmsg))
+	dap.WriteProtocolMessage(s.conn, message)
+}
+
+func (s *Server) onInitializeRequest(request *dap.InitializeRequest) {
+	// TODO(polina): Respond with an error if debug session is in progress?
+	response := &dap.InitializeResponse{Response: *newResponse(request.Request)}
+	response.Body.SupportsConfigurationDoneRequest = true
+	// TODO(polina): support this to match vscode-go functionality
+	response.Body.SupportsSetVariable = false
+	s.send(response)
+}
+
+func (s *Server) onLaunchRequest(request *dap.LaunchRequest) {
+	// TODO(polina): Respond with an error if debug session is in progress?
+	program, ok := request.Arguments["program"]
+	if !ok || program == "" {
+		s.sendErrorResponse(request.Request,
+			FailedToContinue, "Failed to launch",
+			"The program attribute is missing in debug configuration.")
+		return
+	}
+	s.config.ProcessArgs = []string{program.(string)}
+	s.config.WorkingDir = filepath.Dir(program.(string))
+	// TODO: support program args
+
+	stop, ok := request.Arguments["stopOnEntry"]
+	s.stopOnEntry = (ok && stop == true)
+
+	mode, ok := request.Arguments["mode"]
+	if !ok || mode == "" {
+		mode = "debug"
+	}
+	// TODO(polina): support "debug", "test" and "remote" modes
+	if mode != "exec" {
+		s.sendErrorResponse(request.Request,
+			FailedToContinue, "Failed to launch",
+			fmt.Sprintf("Unsupported 'mode' value '%s' in debug configuration.", mode))
+		return
+	}
+
+	config := &debugger.Config{
+		WorkingDir:           s.config.WorkingDir,
+		AttachPid:            0,
+		CoreFile:             "",
+		Backend:              s.config.Backend,
+		Foreground:           s.config.Foreground,
+		DebugInfoDirectories: s.config.DebugInfoDirectories,
+		CheckGoVersion:       s.config.CheckGoVersion,
+	}
+	var err error
+	if s.debugger, err = debugger.New(config, s.config.ProcessArgs); err != nil {
+		s.sendErrorResponse(request.Request,
+			FailedToContinue, "Failed to launch", err.Error())
+		return
+	}
+
+	// Notify the client that the debugger is ready to start accepting
+	// configuration requests for setting breakpoints, etc. The client
+	// will end the configuration sequence with 'configurationDone'.
+	s.send(&dap.InitializedEvent{Event: *newEvent("initialized")})
+	s.send(&dap.LaunchResponse{Response: *newResponse(request.Request)})
+}
+
+// onDisconnectRequest handles the DisconnectRequest. Per the DAP spec,
+// it disconnects the debuggee and signals that the debug adaptor
+// (in our case this TCP server) can be terminated.
+func (s *Server) onDisconnectRequest(request *dap.DisconnectRequest) {
+	s.send(&dap.DisconnectResponse{Response: *newResponse(request.Request)})
+	if s.debugger != nil {
+		_, err := s.debugger.Command(&api.DebuggerCommand{Name: api.Halt})
+		if err != nil {
+			s.log.Error(err)
+		}
+		kill := s.config.AttachPid == 0
+		err = s.debugger.Detach(kill)
+		if err != nil {
+			s.log.Error(err)
+		}
+	}
+	// TODO(polina): make thread-safe when handlers become asynchronous.
+	s.signalDisconnect()
+}
+
+func (s *Server) onSetBreakpointsRequest(request *dap.SetBreakpointsRequest) {
+	if request.Arguments.Source.Path == "" {
+		s.log.Error("ERROR: Unable to set breakpoint for empty file path")
+	}
+	response := &dap.SetBreakpointsResponse{Response: *newResponse(request.Request)}
+	response.Body.Breakpoints = make([]dap.Breakpoint, len(request.Arguments.Breakpoints))
+	// Only verified breakpoints will be set and reported back in the
+	// response. All breakpoints resulting in errors (e.g. duplicates
+	// or lines that do not have statements) will be skipped.
+	i := 0
+	for _, b := range request.Arguments.Breakpoints {
+		bp, err := s.debugger.CreateBreakpoint(
+			&api.Breakpoint{File: request.Arguments.Source.Path, Line: b.Line})
+		if err != nil {
+			s.log.Error("ERROR:", err)
+			continue
+		}
+		response.Body.Breakpoints[i].Verified = true
+		response.Body.Breakpoints[i].Line = bp.Line
+		i++
+	}
+	response.Body.Breakpoints = response.Body.Breakpoints[:i]
+	s.send(response)
+}
+
+func (s *Server) onSetExceptionBreakpointsRequest(request *dap.SetExceptionBreakpointsRequest) {
+	// Unlike what DAP documentation claims, this request is always sent
+	// even though we specified no filters at initializatin. Handle as no-op.
+	s.send(&dap.SetExceptionBreakpointsResponse{Response: *newResponse(request.Request)})
+}
+
+func (s *Server) onConfigurationDoneRequest(request *dap.ConfigurationDoneRequest) {
+	if s.stopOnEntry {
+		e := &dap.StoppedEvent{
+			Event: *newEvent("stopped"),
+			Body:  dap.StoppedEventBody{Reason: "breakpoint", ThreadId: 1, AllThreadsStopped: true},
+		}
+		s.send(e)
+	}
+	s.send(&dap.ConfigurationDoneResponse{Response: *newResponse(request.Request)})
+	if !s.stopOnEntry {
+		s.doContinue()
+	}
+}
+
+func (s *Server) onContinueRequest(request *dap.ContinueRequest) {
+	s.send(&dap.ContinueResponse{Response: *newResponse(request.Request)})
+	s.doContinue()
+}
+
+func (s *Server) sendErrorResponse(request dap.Request, id int, summary string, details string) {
+	er := &dap.ErrorResponse{}
+	er.Type = "response"
+	er.Command = request.Command
+	er.RequestSeq = request.Seq
+	er.Success = false
+	er.Message = summary
+	er.Body.Error.Id = id
+	er.Body.Error.Format = fmt.Sprintf("%s: %s", summary, details)
+	s.log.Error(er.Body.Error.Format)
+	s.send(er)
+}
+
+func (s *Server) sendUnsupportedErrorResponse(request dap.Request) {
+	s.sendErrorResponse(request, UnsupportedCommand, "Unsupported command",
+		fmt.Sprintf("cannot process '%s' request", request.Command))
+}
+
+func newResponse(request dap.Request) *dap.Response {
+	return &dap.Response{
+		ProtocolMessage: dap.ProtocolMessage{
+			Seq:  0,
+			Type: "response",
+		},
+		Command:    request.Command,
+		RequestSeq: request.Seq,
+		Success:    true,
+	}
+}
+
+func newEvent(event string) *dap.Event {
+	return &dap.Event{
+		ProtocolMessage: dap.ProtocolMessage{
+			Seq:  0,
+			Type: "event",
+		},
+		Event: event,
+	}
+}
+
+func (s *Server) doContinue() {
+	if s.debugger == nil {
+		return
+	}
+	state, err := s.debugger.Command(&api.DebuggerCommand{Name: api.Continue})
+	if err != nil {
+		s.log.Error(err)
+		switch err.(type) {
+		case proc.ErrProcessExited:
+			e := &dap.TerminatedEvent{Event: *newEvent("terminated")}
+			s.send(e)
+		default:
+		}
+		return
+	}
+	if state.Exited {
+		e := &dap.TerminatedEvent{Event: *newEvent("terminated")}
+		s.send(e)
+	} else {
+		e := &dap.StoppedEvent{Event: *newEvent("stopped")}
+		// TODO(polina): differentiate between breakpoint and pause on halt.
+		e.Body.Reason = "breakpoint"
+		e.Body.AllThreadsStopped = true
+		e.Body.ThreadId = state.SelectedGoroutine.ID
+		s.send(e)
+	}
+}

service/dap/server_test.go

@@ -0,0 +1,160 @@
+package dap
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"net"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/go-delve/delve/pkg/logflags"
+	protest "github.com/go-delve/delve/pkg/proc/test"
+	"github.com/go-delve/delve/service"
+	"github.com/go-delve/delve/service/dap/daptest"
+	"github.com/google/go-dap"
+)
+
+func TestMain(m *testing.M) {
+	var logOutput string
+	flag.StringVar(&logOutput, "log-output", "", "configures log output")
+	flag.Parse()
+	logflags.Setup(logOutput != "", logOutput, "")
+	os.Exit(protest.RunTestsWithFixtures(m))
+}
+
+func startDAPServer(t *testing.T) (server *Server, addr string) {
+	listener, err := net.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	server = NewServer(&service.Config{
+		Listener:       listener,
+		Backend:        "default",
+		DisconnectChan: nil,
+	})
+	server.Run()
+	// Give server time to start listening for clients
+	time.Sleep(100 * time.Millisecond)
+	return server, listener.Addr().String()
+}
+
+func expectMessage(t *testing.T, client *daptest.Client, want []byte) {
+	got, err := client.ReadBaseMessage()
+	if err != nil {
+		t.Error(err)
+	}
+	if !bytes.Equal(got, want) {
+		t.Errorf("\ngot  %q\nwant %q", got, want)
+	}
+}
+
+// name is for _fixtures/<name>.go
+func runTest(t *testing.T, name string, test func(c *daptest.Client, f protest.Fixture)) {
+	var buildFlags protest.BuildFlags
+	fixture := protest.BuildFixture(name, buildFlags)
+
+	server, addr := startDAPServer(t)
+	client := daptest.NewClient(addr)
+	defer client.Close()
+	defer server.Stop()
+
+	test(client, fixture)
+}
+
+// TODO(polina): instead of hardcoding message bytes,
+// add methods to client to receive, decode and verify responses.
+
+func TestStopOnEntry(t *testing.T) {
+	runTest(t, "increment", func(client *daptest.Client, fixture protest.Fixture) {
+		client.InitializeRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":0,"success":true,"command":"initialize","body":{"supportsConfigurationDoneRequest":true}}`))
+
+		client.LaunchRequest(fixture.Path, true /*stopOnEntry*/)
+		expectMessage(t, client, []byte(`{"seq":0,"type":"event","event":"initialized"}`))
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":1,"success":true,"command":"launch"}`))
+
+		client.SetExceptionBreakpointsRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":2,"success":true,"command":"setExceptionBreakpoints"}`))
+
+		client.ConfigurationDoneRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"event","event":"stopped","body":{"reason":"breakpoint","threadId":1,"allThreadsStopped":true}}`))
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":3,"success":true,"command":"configurationDone"}`))
+
+		client.ContinueRequest(1)
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":4,"success":true,"command":"continue","body":{}}`))
+		expectMessage(t, client, []byte(`{"seq":0,"type":"event","event":"terminated","body":{}}`))
+
+		client.DisconnectRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":5,"success":true,"command":"disconnect"}`))
+	})
+}
+
+func TestSetBreakpoint(t *testing.T) {
+	runTest(t, "increment", func(client *daptest.Client, fixture protest.Fixture) {
+		client.InitializeRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":0,"success":true,"command":"initialize","body":{"supportsConfigurationDoneRequest":true}}`))
+
+		client.LaunchRequest(fixture.Path, false /*stopOnEntry*/)
+		expectMessage(t, client, []byte(`{"seq":0,"type":"event","event":"initialized"}`))
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":1,"success":true,"command":"launch"}`))
+
+		client.SetBreakpointsRequest(fixture.Source, []int{8, 100})
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":2,"success":true,"command":"setBreakpoints","body":{"breakpoints":[{"verified":true,"source":{},"line":8}]}}`))
+
+		client.SetExceptionBreakpointsRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":3,"success":true,"command":"setExceptionBreakpoints"}`))
+
+		client.ConfigurationDoneRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":4,"success":true,"command":"configurationDone"}`))
+
+		client.ContinueRequest(1)
+		expectMessage(t, client, []byte(`{"seq":0,"type":"event","event":"stopped","body":{"reason":"breakpoint","threadId":1,"allThreadsStopped":true}}`))
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":5,"success":true,"command":"continue","body":{}}`))
+
+		client.ContinueRequest(1)
+		expectMessage(t, client, []byte(`{"seq":0,"type":"event","event":"terminated","body":{}}`))
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":6,"success":true,"command":"continue","body":{}}`))
+
+		client.DisconnectRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":7,"success":true,"command":"disconnect"}`))
+	})
+}
+
+func expectErrorResponse(t *testing.T, client *daptest.Client, requestSeq int, command string, message string, id int) *dap.ErrorResponse {
+	response, err := client.ReadErrorResponse()
+	if err != nil {
+		t.Error(err)
+		return nil
+	}
+	got := response.(*dap.ErrorResponse)
+	if got.RequestSeq != requestSeq || got.Command != command || got.Message != message || got.Body.Error.Id != id {
+		want := fmt.Sprintf("{RequestSeq: %d, Command: %q, Message: %q, Id: %d}", requestSeq, command, message, id)
+		t.Errorf("\ngot  %#v\nwant %s", got, want)
+		return nil
+	}
+	return got
+}
+
+func TestBadLaunchRequests(t *testing.T) {
+	runTest(t, "increment", func(client *daptest.Client, fixture protest.Fixture) {
+		client.LaunchRequest("", true)
+		// Test for the DAP-specific detailed error message.
+		want := "Failed to launch: The program attribute is missing in debug configuration."
+		if got := expectErrorResponse(t, client, 0, "launch", "Failed to launch", 3000); got != nil && got.Body.Error.Format != want {
+			t.Errorf("got %q, want %q", got.Body.Error.Format, want)
+		}
+
+		// Skip detailed message checks for potentially different OS-specific errors.
+		client.LaunchRequest(fixture.Path+"_does_not_exist", false)
+		expectErrorResponse(t, client, 1, "launch", "Failed to launch", 3000)
+
+		client.LaunchRequest(fixture.Source, true) // Not an executable
+		expectErrorResponse(t, client, 2, "launch", "Failed to launch", 3000)
+
+		// We failed to launch the program. Make sure shutdown still works.
+		client.DisconnectRequest()
+		expectMessage(t, client, []byte(`{"seq":0,"type":"response","request_seq":3,"success":true,"command":"disconnect"}`))
+	})
+}

vendor/github.com/google/go-dap/.travis.yml

@@ -0,0 +1,12 @@
+language: go
+
+go:
+- 1.13.x
+
+env:
+  global:
+  - GOPROXY=https://proxy.golang.org
+  - GO111MODULE=on
+
+script:
+  - 'internal/test.sh'

vendor/github.com/google/go-dap/LICENSE

@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+      the conditions stated in this License.
+
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+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
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+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
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+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
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+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
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+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
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+
+       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.

vendor/github.com/google/go-dap/README.md

@@ -0,0 +1,19 @@
+# go-dap: Go implementation of the Debug Adapter Protocol
+
+[![Build Status](https://travis-ci.org/google/go-dap.svg?branch=master)](https://travis-ci.org/google/go-dap)
+[![Go Report Card](https://goreportcard.com/badge/github.com/google/go-dap)](https://goreportcard.com/report/github.com/google/go-dap)
+
+For an overview of DAP, see
+https://microsoft.github.io/debug-adapter-protocol/overview
+
+## Contributing
+
+We'd love to accept your patches and contributions to this project. See
+[docs/contributing](https://github.com/google/go-dap/blob/master/docs/contributing.md)
+for more details.
+
+## License
+
+This project is licensed under the Apache License 2.0
+
+This is not an officially supported Google product.

vendor/github.com/google/go-dap/codec.go

@@ -0,0 +1,219 @@
+// Copyright 2019 Google LLC
+//
+// 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
+//
+//     https://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.
+
+// This file contains utilities for decoding JSON-encoded bytes into DAP message.
+
+package dap
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// DecodeProtocolMessageFieldError describes which JSON attribute
+// has an unsupported value that the decoding cannot handle.
+type DecodeProtocolMessageFieldError struct {
+	SubType    string
+	FieldName  string
+	FieldValue string
+}
+
+func (e *DecodeProtocolMessageFieldError) Error() string {
+	return fmt.Sprintf("%s %s '%s' is not supported", e.SubType, e.FieldName, e.FieldValue)
+}
+
+// DecodeProtocolMessage parses the JSON-encoded data and returns the result of
+// the appropriate type within the ProtocolMessage hierarchy. If message type,
+// command, etc cannot be cast, returns DecodeProtocolMessageFieldError.
+// See also godoc for json.Unmarshal, which is used for underlying decoding.
+func DecodeProtocolMessage(data []byte) (Message, error) {
+	var protomsg ProtocolMessage
+	if err := json.Unmarshal(data, &protomsg); err != nil {
+		return nil, err
+	}
+	switch protomsg.Type {
+	case "request":
+		return decodeRequest(data)
+	case "response":
+		return decodeResponse(data)
+	case "event":
+		return decodeEvent(data)
+	default:
+		return nil, &DecodeProtocolMessageFieldError{"ProtocolMessage", "type", protomsg.Type}
+	}
+}
+
+type messageCtor func() Message
+
+// decodeRequest determines what request type in the ProtocolMessage hierarchy
+// data corresponds to and uses json.Unmarshal to populate the corresponding
+// struct to be returned.
+func decodeRequest(data []byte) (Message, error) {
+	var r Request
+	if err := json.Unmarshal(data, &r); err != nil {
+		return nil, err
+	}
+	if ctor, ok := requestCtor[r.Command]; ok {
+		requestPtr := ctor()
+		err := json.Unmarshal(data, requestPtr)
+		return requestPtr, err
+	}
+	return nil, &DecodeProtocolMessageFieldError{"Request", "command", r.Command}
+}
+
+// Mapping of request commands and corresponding struct constructors that
+// can be passed to json.Unmarshal.
+var requestCtor = map[string]messageCtor{
+	"cancel":                  func() Message { return &CancelRequest{} },
+	"runInTerminal":           func() Message { return &RunInTerminalRequest{} },
+	"initialize":              func() Message { return &InitializeRequest{} },
+	"configurationDone":       func() Message { return &ConfigurationDoneRequest{} },
+	"launch":                  func() Message { return &LaunchRequest{} },
+	"attach":                  func() Message { return &AttachRequest{} },
+	"restart":                 func() Message { return &RestartRequest{} },
+	"disconnect":              func() Message { return &DisconnectRequest{} },
+	"terminate":               func() Message { return &TerminateRequest{} },
+	"breakpointLocations":     func() Message { return &BreakpointLocationsRequest{} },
+	"setBreakpoints":          func() Message { return &SetBreakpointsRequest{} },
+	"setFunctionBreakpoints":  func() Message { return &SetFunctionBreakpointsRequest{} },
+	"setExceptionBreakpoints": func() Message { return &SetExceptionBreakpointsRequest{} },
+	"dataBreakpointInfo":      func() Message { return &DataBreakpointInfoRequest{} },
+	"setDataBreakpoints":      func() Message { return &SetDataBreakpointsRequest{} },
+	"continue":                func() Message { return &ContinueRequest{} },
+	"next":                    func() Message { return &NextRequest{} },
+	"stepIn":                  func() Message { return &StepInRequest{} },
+	"stepOut":                 func() Message { return &StepOutRequest{} },
+	"stepBack":                func() Message { return &StepBackRequest{} },
+	"reverseContinue":         func() Message { return &ReverseContinueRequest{} },
+	"restartFrame":            func() Message { return &RestartFrameRequest{} },
+	"goto":                    func() Message { return &GotoRequest{} },
+	"pause":                   func() Message { return &PauseRequest{} },
+	"stackTrace":              func() Message { return &StackTraceRequest{} },
+	"scopes":                  func() Message { return &ScopesRequest{} },
+	"variables":               func() Message { return &VariablesRequest{} },
+	"setVariable":             func() Message { return &SetVariableRequest{} },
+	"source":                  func() Message { return &SourceRequest{} },
+	"threads":                 func() Message { return &ThreadsRequest{} },
+	"terminateThreads":        func() Message { return &TerminateThreadsRequest{} },
+	"modules":                 func() Message { return &ModulesRequest{} },
+	"loadedSources":           func() Message { return &LoadedSourcesRequest{} },
+	"evaluate":                func() Message { return &EvaluateRequest{} },
+	"setExpression":           func() Message { return &SetExpressionRequest{} },
+	"stepInTargets":           func() Message { return &StepInTargetsRequest{} },
+	"gotoTargets":             func() Message { return &GotoTargetsRequest{} },
+	"completions":             func() Message { return &CompletionsRequest{} },
+	"exceptionInfo":           func() Message { return &ExceptionInfoRequest{} },
+	"readMemory":              func() Message { return &ReadMemoryRequest{} },
+	"disassemble":             func() Message { return &DisassembleRequest{} },
+}
+
+// decodeResponse determines what response type in the ProtocolMessage hierarchy
+// data corresponds to and uses json.Unmarshal to populate the corresponding
+// struct to be returned.
+func decodeResponse(data []byte) (Message, error) {
+	var r Response
+	if err := json.Unmarshal(data, &r); err != nil {
+		return nil, err
+	}
+	if !r.Success {
+		var er ErrorResponse
+		err := json.Unmarshal(data, &er)
+		return &er, err
+	}
+	if ctor, ok := responseCtor[r.Command]; ok {
+		responsePtr := ctor()
+		err := json.Unmarshal(data, responsePtr)
+		return responsePtr, err
+	}
+	return nil, &DecodeProtocolMessageFieldError{"Response", "command", r.Command}
+}
+
+// Mapping of response commands and corresponding struct constructors that
+// can be passed to json.Unmarshal.
+var responseCtor = map[string]messageCtor{
+	"cancel":                  func() Message { return &CancelResponse{} },
+	"runInTerminal":           func() Message { return &RunInTerminalResponse{} },
+	"initialize":              func() Message { return &InitializeResponse{} },
+	"configurationDone":       func() Message { return &ConfigurationDoneResponse{} },
+	"launch":                  func() Message { return &LaunchResponse{} },
+	"attach":                  func() Message { return &AttachResponse{} },
+	"restart":                 func() Message { return &RestartResponse{} },
+	"disconnect":              func() Message { return &DisconnectResponse{} },
+	"terminate":               func() Message { return &TerminateResponse{} },
+	"breakpointLocations":     func() Message { return &BreakpointLocationsResponse{} },
+	"setBreakpoints":          func() Message { return &SetBreakpointsResponse{} },
+	"setFunctionBreakpoints":  func() Message { return &SetFunctionBreakpointsResponse{} },
+	"setExceptionBreakpoints": func() Message { return &SetExceptionBreakpointsResponse{} },
+	"dataBreakpointInfo":      func() Message { return &DataBreakpointInfoResponse{} },
+	"setDataBreakpoints":      func() Message { return &SetDataBreakpointsResponse{} },
+	"continue":                func() Message { return &ContinueResponse{} },
+	"next":                    func() Message { return &NextResponse{} },
+	"stepIn":                  func() Message { return &StepInResponse{} },
+	"stepOut":                 func() Message { return &StepOutResponse{} },
+	"stepBack":                func() Message { return &StepBackResponse{} },
+	"reverseContinue":         func() Message { return &ReverseContinueResponse{} },
+	"restartFrame":            func() Message { return &RestartFrameResponse{} },
+	"goto":                    func() Message { return &GotoResponse{} },
+	"pause":                   func() Message { return &PauseResponse{} },
+	"stackTrace":              func() Message { return &StackTraceResponse{} },
+	"scopes":                  func() Message { return &ScopesResponse{} },
+	"variables":               func() Message { return &VariablesResponse{} },
+	"setVariable":             func() Message { return &SetVariableResponse{} },
+	"source":                  func() Message { return &SourceResponse{} },
+	"threads":                 func() Message { return &ThreadsResponse{} },
+	"terminateThreads":        func() Message { return &TerminateThreadsResponse{} },
+	"modules":                 func() Message { return &ModulesResponse{} },
+	"loadedSources":           func() Message { return &LoadedSourcesResponse{} },
+	"evaluate":                func() Message { return &EvaluateResponse{} },
+	"setExpression":           func() Message { return &SetExpressionResponse{} },
+	"stepInTargets":           func() Message { return &StepInTargetsResponse{} },
+	"gotoTargets":             func() Message { return &GotoTargetsResponse{} },
+	"completions":             func() Message { return &CompletionsResponse{} },
+	"exceptionInfo":           func() Message { return &ExceptionInfoResponse{} },
+	"readMemory":              func() Message { return &ReadMemoryResponse{} },
+	"disassemble":             func() Message { return &DisassembleResponse{} },
+}
+
+// decodeEvent determines what event type in the ProtocolMessage hierarchy
+// data corresponds to and uses json.Unmarshal to populate the corresponding
+// struct to be returned.
+func decodeEvent(data []byte) (Message, error) {
+	var e Event
+	if err := json.Unmarshal(data, &e); err != nil {
+		return nil, err
+	}
+	if ctor, ok := eventCtor[e.Event]; ok {
+		eventPtr := ctor()
+		err := json.Unmarshal(data, eventPtr)
+		return eventPtr, err
+	}
+	return nil, &DecodeProtocolMessageFieldError{"Event", "event", e.Event}
+}
+
+// Mapping of event ids and corresponding struct constructors that
+// can be passed to json.Unmarshal.
+var eventCtor = map[string]messageCtor{
+	"initialized":  func() Message { return &InitializedEvent{} },
+	"stopped":      func() Message { return &StoppedEvent{} },
+	"continued":    func() Message { return &ContinuedEvent{} },
+	"exited":       func() Message { return &ExitedEvent{} },
+	"terminated":   func() Message { return &TerminatedEvent{} },
+	"thread":       func() Message { return &ThreadEvent{} },
+	"output":       func() Message { return &OutputEvent{} },
+	"breakpoint":   func() Message { return &BreakpointEvent{} },
+	"module":       func() Message { return &ModuleEvent{} },
+	"loadedSource": func() Message { return &LoadedSourceEvent{} },
+	"process":      func() Message { return &ProcessEvent{} },
+	"capabilities": func() Message { return &CapabilitiesEvent{} },
+}

vendor/github.com/google/go-dap/go.mod

@@ -0,0 +1,3 @@
+module github.com/google/go-dap
+
+go 1.13

vendor/github.com/google/go-dap/io.go

@@ -0,0 +1,137 @@
+// Copyright 2019 Google LLC
+//
+// 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
+//
+//     https://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.
+
+// This file contains utilities for DAP Base protocol I/O.
+// For additional information, see "Base protocol" section in
+// https://microsoft.github.io/debug-adapter-protocol/overview.
+
+package dap
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// BaseProtocolError represents base protocol error, which occurs when the raw
+// message does not conform to the header+content format of the base protocol.
+type BaseProtocolError struct {
+	Err string
+}
+
+func (bpe *BaseProtocolError) Error() string { return bpe.Err }
+
+var (
+	// ErrHeaderDelimiterNotCrLfCrLf is returned when only partial header
+	// delimiter \r\n\r\n is encountered.
+	ErrHeaderDelimiterNotCrLfCrLf = &BaseProtocolError{fmt.Sprintf("header delimiter is not %q", crLfcrLf)}
+
+	// ErrHeaderNotContentLength is returned when the parsed header is
+	// not of valid Content-Length format.
+	ErrHeaderNotContentLength = &BaseProtocolError{fmt.Sprintf("header format is not %q", contentLengthHeaderRegex)}
+
+	// ErrHeaderContentTooLong is returned when the content length specified in
+	// the header is above contentMaxLength.
+	ErrHeaderContentTooLong = &BaseProtocolError{fmt.Sprintf("content length over %v bytes", contentMaxLength)}
+)
+
+const (
+	crLfcrLf               = "\r\n\r\n"
+	contentLengthHeaderFmt = "Content-Length: %d\r\n\r\n"
+	contentMaxLength       = 4 * 1024 * 1024
+)
+
+var (
+	contentLengthHeaderRegex = regexp.MustCompile("^Content-Length: ([0-9]+)$")
+)
+
+// WriteBaseMessage formats content with Content-Length header and delimiters
+// as per the base protocol and writes the resulting message to w.
+func WriteBaseMessage(w io.Writer, content []byte) error {
+	header := fmt.Sprintf(contentLengthHeaderFmt, len(content))
+	if _, err := w.Write([]byte(header)); err != nil {
+		return err
+	}
+	_, err := w.Write(content)
+	return err
+}
+
+// ReadBaseMessage reads one message from r consisting of a Content-Length
+// header and a content part. It parses the header to determine the size of
+// the content part and extracts and returns the actual content of the message.
+// Returns nil bytes on error, which can be one of the standard IO errors or
+// a BaseProtocolError defined in this package.
+func ReadBaseMessage(r *bufio.Reader) ([]byte, error) {
+	contentLength, err := readContentLengthHeader(r)
+	if err != nil {
+		return nil, err
+	}
+	if contentLength > contentMaxLength {
+		return nil, ErrHeaderContentTooLong
+	}
+	content := make([]byte, contentLength)
+	if _, err = io.ReadFull(r, content); err != nil {
+		return nil, err
+	}
+	return content, nil
+}
+
+// readContentLengthHeader looks for the only header field that is supported
+// and required:
+// 		Content-Length: [0-9]+\r\n\r\n
+// Extracts and returns the content length.
+func readContentLengthHeader(r *bufio.Reader) (contentLength int, err error) {
+	// Look for <some header>\r\n\r\n
+	headerWithCr, err := r.ReadString('\r')
+	if err != nil {
+		return 0, err
+	}
+	nextThree := make([]byte, 3)
+	if _, err = io.ReadFull(r, nextThree); err != nil {
+		return 0, err
+	}
+	if string(nextThree) != "\n\r\n" {
+		return 0, ErrHeaderDelimiterNotCrLfCrLf
+	}
+
+	// If header is in the right format, get the length
+	header := strings.TrimSuffix(headerWithCr, "\r")
+	headerAndLength := contentLengthHeaderRegex.FindStringSubmatch(header)
+	if len(headerAndLength) < 2 {
+		return 0, ErrHeaderNotContentLength
+	}
+	return strconv.Atoi(headerAndLength[1])
+}
+
+// WriteProtocolMessage encodes message and writes it to w.
+func WriteProtocolMessage(w io.Writer, message Message) error {
+	b, err := json.Marshal(message)
+	if err != nil {
+		return err
+	}
+	return WriteBaseMessage(w, b)
+}
+
+// ReadProtocolMessage reads a message from r, decodes and returns it.
+func ReadProtocolMessage(r *bufio.Reader) (Message, error) {
+	content, err := ReadBaseMessage(r)
+	if err != nil {
+		return nil, err
+	}
+	return DecodeProtocolMessage(content)
+}