internal/lsp/general.go - tools - Git at Google

 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package lsp

 import (
 	"bytes"
 	"context"
 	"fmt"
 	"io"
 	"os"
 	"path"
 	"sync"

 	"golang.org/x/tools/internal/event"
 	"golang.org/x/tools/internal/jsonrpc2"
 	"golang.org/x/tools/internal/lsp/debug"
 	"golang.org/x/tools/internal/lsp/debug/tag"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/span"
 )

 func (s *Server) initialize(ctx context.Context, params *protocol.ParamInitialize) (*protocol.InitializeResult, error) {
 	s.stateMu.Lock()
 	if s.state >= serverInitializing {
 		defer s.stateMu.Unlock()
 		return nil, fmt.Errorf("%w: initialize called while server in %v state", jsonrpc2.ErrInvalidRequest, s.state)
 	}
 	s.state = serverInitializing
 	s.stateMu.Unlock()

 	s.progress.supportsWorkDoneProgress = params.Capabilities.Window.WorkDoneProgress

 	options := s.session.Options()
 	defer func() { s.session.SetOptions(options) }()

 	if err := s.handleOptionResults(ctx, source.SetOptions(&options, params.InitializationOptions)); err != nil {
 		return nil, err
 	}
 	options.ForClientCapabilities(params.Capabilities)

 	// gopls only supports URIs with a file:// scheme. Any other URIs will not
 	// work, so fail to initialize. See golang/go#40272.
 	if params.RootURI != "" && !params.RootURI.SpanURI().IsFile() {
 		return nil, fmt.Errorf("unsupported URI scheme: %v (gopls only supports file URIs)", params.RootURI)
 	}
 	for _, folder := range params.WorkspaceFolders {
 		uri := span.URIFromURI(folder.URI)
 		if !uri.IsFile() {
 			return nil, fmt.Errorf("unsupported URI scheme: %q (gopls only supports file URIs)", folder.URI)
 		}
 	}

 	s.pendingFolders = params.WorkspaceFolders
 	if len(s.pendingFolders) == 0 {
 		if params.RootURI != "" {
 			s.pendingFolders = []protocol.WorkspaceFolder{{
 				URI:  string(params.RootURI),
 				Name: path.Base(params.RootURI.SpanURI().Filename()),
 			}}
 		}
 	}

 	var codeActionProvider interface{} = true
 	if ca := params.Capabilities.TextDocument.CodeAction; len(ca.CodeActionLiteralSupport.CodeActionKind.ValueSet) > 0 {
 		// If the client has specified CodeActionLiteralSupport,
 		// send the code actions we support.
 		//
 		// Using CodeActionOptions is only valid if codeActionLiteralSupport is set.
 		codeActionProvider = &protocol.CodeActionOptions{
 			CodeActionKinds: s.getSupportedCodeActions(),
 		}
 	}
 	var renameOpts interface{} = true
 	if r := params.Capabilities.TextDocument.Rename; r.PrepareSupport {
 		renameOpts = protocol.RenameOptions{
 			PrepareProvider: r.PrepareSupport,
 		}
 	}

 	goplsVer := &bytes.Buffer{}
 	debug.PrintVersionInfo(ctx, goplsVer, true, debug.PlainText)

 	return &protocol.InitializeResult{
 		Capabilities: protocol.ServerCapabilities{
 			CallHierarchyProvider: true,
 			CodeActionProvider:    codeActionProvider,
 			CompletionProvider: protocol.CompletionOptions{
 				TriggerCharacters: []string{"."},
 			},
 			DefinitionProvider:         true,
 			TypeDefinitionProvider:     true,
 			ImplementationProvider:     true,
 			DocumentFormattingProvider: true,
 			DocumentSymbolProvider:     true,
 			WorkspaceSymbolProvider:    true,
 			ExecuteCommandProvider: protocol.ExecuteCommandOptions{
 				Commands: options.SupportedCommands,
 			},
 			FoldingRangeProvider:      true,
 			HoverProvider:             true,
 			DocumentHighlightProvider: true,
 			DocumentLinkProvider:      protocol.DocumentLinkOptions{},
 			ReferencesProvider:        true,
 			RenameProvider:            renameOpts,
 			SignatureHelpProvider: protocol.SignatureHelpOptions{
 				TriggerCharacters: []string{"(", ","},
 			},
 			TextDocumentSync: &protocol.TextDocumentSyncOptions{
 				Change:    protocol.Incremental,
 				OpenClose: true,
 				Save: protocol.SaveOptions{
 					IncludeText: false,
 				},
 			},
 			Workspace: protocol.WorkspaceGn{
 				WorkspaceFolders: protocol.WorkspaceFoldersGn{
 					Supported:           true,
 					ChangeNotifications: "workspace/didChangeWorkspaceFolders",
 				},
 			},
 		},
 		ServerInfo: struct {
 			Name    string `json:"name"`
 			Version string `json:"version,omitempty"`
 		}{
 			Name:    "gopls",
 			Version: goplsVer.String(),
 		},
 	}, nil
 }

 func (s *Server) initialized(ctx context.Context, params *protocol.InitializedParams) error {
 	s.stateMu.Lock()
 	if s.state >= serverInitialized {
 		defer s.stateMu.Unlock()
 		return fmt.Errorf("%w: initalized called while server in %v state", jsonrpc2.ErrInvalidRequest, s.state)
 	}
 	s.state = serverInitialized
 	s.stateMu.Unlock()

 	options := s.session.Options()
 	defer func() { s.session.SetOptions(options) }()

 	var registrations []protocol.Registration
 	if options.ConfigurationSupported && options.DynamicConfigurationSupported {
 		registrations = append(registrations,
 			protocol.Registration{
 				ID:     "workspace/didChangeConfiguration",
 				Method: "workspace/didChangeConfiguration",
 			},
 			protocol.Registration{
 				ID:     "workspace/didChangeWorkspaceFolders",
 				Method: "workspace/didChangeWorkspaceFolders",
 			},
 		)
 	}

 	// TODO: this event logging may be unnecessary.
 	// The version info is included in the initialize response.
 	buf := &bytes.Buffer{}
 	debug.PrintVersionInfo(ctx, buf, true, debug.PlainText)
 	event.Log(ctx, buf.String())

 	if err := s.addFolders(ctx, s.pendingFolders); err != nil {
 		return err
 	}
 	s.pendingFolders = nil

 	if len(registrations) > 0 {
 		if err := s.client.RegisterCapability(ctx, &protocol.RegistrationParams{
 			Registrations: registrations,
 		}); err != nil {
 			return err
 		}
 	}
 	return nil
 }

 func (s *Server) addFolders(ctx context.Context, folders []protocol.WorkspaceFolder) error {
 	originalViews := len(s.session.Views())
 	viewErrors := make(map[span.URI]error)

 	var wg sync.WaitGroup
 	if s.session.Options().VerboseWorkDoneProgress {
 		work := s.progress.start(ctx, DiagnosticWorkTitle(FromInitialWorkspaceLoad), "Calculating diagnostics for initial workspace load...", nil, nil)
 		defer func() {
 			go func() {
 				wg.Wait()
 				work.end(ctx, "Done.")
 			}()
 		}()
 	}
 	dirsToWatch := map[span.URI]struct{}{}
 	for _, folder := range folders {
 		uri := span.URIFromURI(folder.URI)
 		view, snapshot, release, err := s.addView(ctx, folder.Name, uri)
 		if err != nil {
 			viewErrors[uri] = err
 			continue
 		}
 		for _, dir := range snapshot.WorkspaceDirectories(ctx) {
 			dirsToWatch[dir] = struct{}{}
 		}

 		// Print each view's environment.
 		buf := &bytes.Buffer{}
 		if err := view.WriteEnv(ctx, buf); err != nil {
 			event.Error(ctx, "failed to write environment", err, tag.Directory.Of(view.Folder().Filename()))
 			continue
 		}
 		event.Log(ctx, buf.String())

 		// Diagnose the newly created view.
 		wg.Add(1)
 		go func() {
 			s.diagnoseDetached(snapshot)
 			release()
 			wg.Done()
 		}()
 	}
 	// Register for file watching notifications, if they are supported.
 	s.watchedDirectoriesMu.Lock()
 	err := s.registerWatchedDirectoriesLocked(ctx, dirsToWatch)
 	s.watchedDirectoriesMu.Unlock()
 	if err != nil {
 		return err
 	}
 	if len(viewErrors) > 0 {
 		errMsg := fmt.Sprintf("Error loading workspace folders (expected %v, got %v)\n", len(folders), len(s.session.Views())-originalViews)
 		for uri, err := range viewErrors {
 			errMsg += fmt.Sprintf("failed to load view for %s: %v\n", uri, err)
 		}
 		return s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
 			Type:    protocol.Error,
 			Message: errMsg,
 		})
 	}
 	return nil
 }

 // updateWatchedDirectories compares the current set of directories to watch
 // with the previously registered set of directories. If the set of directories
 // has changed, we unregister and re-register for file watching notifications.
 // updatedSnapshots is the set of snapshots that have been updated.
 func (s *Server) updateWatchedDirectories(ctx context.Context, updatedSnapshots []source.Snapshot) error {
 	dirsToWatch := map[span.URI]struct{}{}
 	seenViews := map[source.View]struct{}{}

 	// Collect all of the workspace directories from the updated snapshots.
 	for _, snapshot := range updatedSnapshots {
 		seenViews[snapshot.View()] = struct{}{}
 		for _, dir := range snapshot.WorkspaceDirectories(ctx) {
 			dirsToWatch[dir] = struct{}{}
 		}
 	}
 	// Not all views were necessarily updated, so check the remaining views.
 	for _, view := range s.session.Views() {
 		if _, ok := seenViews[view]; ok {
 			continue
 		}
 		snapshot, release := view.Snapshot(ctx)
 		for _, dir := range snapshot.WorkspaceDirectories(ctx) {
 			dirsToWatch[dir] = struct{}{}
 		}
 		release()
 	}

 	s.watchedDirectoriesMu.Lock()
 	defer s.watchedDirectoriesMu.Unlock()

 	// Nothing to do if the set of workspace directories is unchanged.
 	if equalURISet(s.watchedDirectories, dirsToWatch) {
 		return nil
 	}

 	// If the set of directories to watch has changed, register the updates and
 	// unregister the previously watched directories. This ordering avoids a
 	// period where no files are being watched. Still, if a user makes on-disk
 	// changes before these updates are complete, we may miss them for the new
 	// directories.
 	if s.watchRegistrationCount > 0 {
 		prevID := s.watchRegistrationCount - 1
 		if err := s.registerWatchedDirectoriesLocked(ctx, dirsToWatch); err != nil {
 			return err
 		}
 		return s.client.UnregisterCapability(ctx, &protocol.UnregistrationParams{
 			Unregisterations: []protocol.Unregistration{{
 				ID:     watchedFilesCapabilityID(prevID),
 				Method: "workspace/didChangeWatchedFiles",
 			}},
 		})
 	}
 	return nil
 }

 func watchedFilesCapabilityID(id uint64) string {
 	return fmt.Sprintf("workspace/didChangeWatchedFiles-%d", id)
 }

 func equalURISet(m1, m2 map[span.URI]struct{}) bool {
 	if len(m1) != len(m2) {
 		return false
 	}
 	for k := range m1 {
 		_, ok := m2[k]
 		if !ok {
 			return false
 		}
 	}
 	return true
 }

 // registerWatchedDirectoriesLocked sends the workspace/didChangeWatchedFiles
 // registrations to the client and updates s.watchedDirectories.
 func (s *Server) registerWatchedDirectoriesLocked(ctx context.Context, dirs map[span.URI]struct{}) error {
 	if !s.session.Options().DynamicWatchedFilesSupported {
 		return nil
 	}
 	for k := range s.watchedDirectories {
 		delete(s.watchedDirectories, k)
 	}
 	var watchers []protocol.FileSystemWatcher
 	for dir := range dirs {
 		watchers = append(watchers, protocol.FileSystemWatcher{
 			GlobPattern: fmt.Sprintf("%s/**/*.{go,mod,sum}", dir),
 			Kind:        float64(protocol.WatchChange + protocol.WatchDelete + protocol.WatchCreate),
 		})
 	}
 	if err := s.client.RegisterCapability(ctx, &protocol.RegistrationParams{
 		Registrations: []protocol.Registration{{
 			ID:     watchedFilesCapabilityID(s.watchRegistrationCount),
 			Method: "workspace/didChangeWatchedFiles",
 			RegisterOptions: protocol.DidChangeWatchedFilesRegistrationOptions{
 				Watchers: watchers,
 			},
 		}},
 	}); err != nil {
 		return err
 	}
 	s.watchRegistrationCount++

 	for dir := range dirs {
 		s.watchedDirectories[dir] = struct{}{}
 	}
 	return nil
 }

 func (s *Server) fetchConfig(ctx context.Context, name string, folder span.URI, o *source.Options) error {
 	if !s.session.Options().ConfigurationSupported {
 		return nil
 	}
 	v := protocol.ParamConfiguration{
 		ConfigurationParams: protocol.ConfigurationParams{
 			Items: []protocol.ConfigurationItem{{
 				ScopeURI: string(folder),
 				Section:  "gopls",
 			}, {
 				ScopeURI: string(folder),
 				Section:  fmt.Sprintf("gopls-%s", name),
 			}},
 		},
 	}
 	configs, err := s.client.Configuration(ctx, &v)
 	if err != nil {
 		return fmt.Errorf("failed to get workspace configuration from client (%s): %v", folder, err)
 	}
 	for _, config := range configs {
 		if err := s.handleOptionResults(ctx, source.SetOptions(o, config)); err != nil {
 			return err
 		}
 	}
 	return nil
 }

 func (s *Server) handleOptionResults(ctx context.Context, results source.OptionResults) error {
 	for _, result := range results {
 		if result.Error != nil {
 			if err := s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
 				Type:    protocol.Error,
 				Message: result.Error.Error(),
 			}); err != nil {
 				return err
 			}
 		}
 		switch result.State {
 		case source.OptionUnexpected:
 			if err := s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
 				Type:    protocol.Error,
 				Message: fmt.Sprintf("unexpected config %s", result.Name),
 			}); err != nil {
 				return err
 			}
 		case source.OptionDeprecated:
 			msg := fmt.Sprintf("config %s is deprecated", result.Name)
 			if result.Replacement != "" {
 				msg = fmt.Sprintf("%s, use %s instead", msg, result.Replacement)
 			}
 			if err := s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
 				Type:    protocol.Warning,
 				Message: msg,
 			}); err != nil {
 				return err
 			}
 		}
 	}
 	return nil
 }

 // beginFileRequest checks preconditions for a file-oriented request and routes
 // it to a snapshot.
 // We don't want to return errors for benign conditions like wrong file type,
 // so callers should do if !ok { return err } rather than if err != nil.
 func (s *Server) beginFileRequest(ctx context.Context, pURI protocol.DocumentURI, expectKind source.FileKind) (source.Snapshot, source.VersionedFileHandle, bool, func(), error) {
 	uri := pURI.SpanURI()
 	if !uri.IsFile() {
 		// Not a file URI. Stop processing the request, but don't return an error.
 		return nil, nil, false, func() {}, nil
 	}
 	view, err := s.session.ViewOf(uri)
 	if err != nil {
 		return nil, nil, false, func() {}, err
 	}
 	snapshot, release := view.Snapshot(ctx)
 	fh, err := snapshot.GetFile(ctx, uri)
 	if err != nil {
 		release()
 		return nil, nil, false, func() {}, err
 	}
 	if expectKind != source.UnknownKind && fh.Kind() != expectKind {
 		// Wrong kind of file. Nothing to do.
 		release()
 		return nil, nil, false, func() {}, nil
 	}
 	return snapshot, fh, true, release, nil
 }

 func (s *Server) shutdown(ctx context.Context) error {
 	s.stateMu.Lock()
 	defer s.stateMu.Unlock()
 	if s.state < serverInitialized {
 		event.Log(ctx, "server shutdown without initialization")
 	}
 	if s.state != serverShutDown {
 		// drop all the active views
 		s.session.Shutdown(ctx)
 		s.state = serverShutDown
 	}
 	return nil
 }

 func (s *Server) exit(ctx context.Context) error {
 	s.stateMu.Lock()
 	defer s.stateMu.Unlock()

 	// TODO: We need a better way to find the conn close method.
 	s.client.(io.Closer).Close()

 	if s.state != serverShutDown {
 		// TODO: We should be able to do better than this.
 		os.Exit(1)
 	}
 	// we don't terminate the process on a normal exit, we just allow it to
 	// close naturally if needed after the connection is closed.
 	return nil
 }
	// Copyright 2019 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package lsp

	import (
	"bytes"
	"context"
	"fmt"
	"io"
	"os"
	"path"
	"sync"

	"golang.org/x/tools/internal/event"
	"golang.org/x/tools/internal/jsonrpc2"
	"golang.org/x/tools/internal/lsp/debug"
	"golang.org/x/tools/internal/lsp/debug/tag"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/span"
	)

	func (s Server) initialize(ctx context.Context, params protocol.ParamInitialize) (*protocol.InitializeResult, error) {
	s.stateMu.Lock()
	if s.state >= serverInitializing {
	defer s.stateMu.Unlock()
	return nil, fmt.Errorf("%w: initialize called while server in %v state", jsonrpc2.ErrInvalidRequest, s.state)
	}
	s.state = serverInitializing
	s.stateMu.Unlock()

	s.progress.supportsWorkDoneProgress = params.Capabilities.Window.WorkDoneProgress

	options := s.session.Options()
	defer func() { s.session.SetOptions(options) }()

	if err := s.handleOptionResults(ctx, source.SetOptions(&options, params.InitializationOptions)); err != nil {
	return nil, err
	}
	options.ForClientCapabilities(params.Capabilities)

	// gopls only supports URIs with a file:// scheme. Any other URIs will not
	// work, so fail to initialize. See golang/go#40272.
	if params.RootURI != "" && !params.RootURI.SpanURI().IsFile() {
	return nil, fmt.Errorf("unsupported URI scheme: %v (gopls only supports file URIs)", params.RootURI)
	}
	for _, folder := range params.WorkspaceFolders {
	uri := span.URIFromURI(folder.URI)
	if !uri.IsFile() {
	return nil, fmt.Errorf("unsupported URI scheme: %q (gopls only supports file URIs)", folder.URI)
	}
	}

	s.pendingFolders = params.WorkspaceFolders
	if len(s.pendingFolders) == 0 {
	if params.RootURI != "" {
	s.pendingFolders = []protocol.WorkspaceFolder{{
	URI: string(params.RootURI),
	Name: path.Base(params.RootURI.SpanURI().Filename()),
	}}
	}
	}

	var codeActionProvider interface{} = true
	if ca := params.Capabilities.TextDocument.CodeAction; len(ca.CodeActionLiteralSupport.CodeActionKind.ValueSet) > 0 {
	// If the client has specified CodeActionLiteralSupport,
	// send the code actions we support.
	//
	// Using CodeActionOptions is only valid if codeActionLiteralSupport is set.
	codeActionProvider = &protocol.CodeActionOptions{
	CodeActionKinds: s.getSupportedCodeActions(),
	}
	}
	var renameOpts interface{} = true
	if r := params.Capabilities.TextDocument.Rename; r.PrepareSupport {
	renameOpts = protocol.RenameOptions{
	PrepareProvider: r.PrepareSupport,
	}
	}

	goplsVer := &bytes.Buffer{}
	debug.PrintVersionInfo(ctx, goplsVer, true, debug.PlainText)

	return &protocol.InitializeResult{
	Capabilities: protocol.ServerCapabilities{
	CallHierarchyProvider: true,
	CodeActionProvider: codeActionProvider,
	CompletionProvider: protocol.CompletionOptions{
	TriggerCharacters: []string{"."},
	},
	DefinitionProvider: true,
	TypeDefinitionProvider: true,
	ImplementationProvider: true,
	DocumentFormattingProvider: true,
	DocumentSymbolProvider: true,
	WorkspaceSymbolProvider: true,
	ExecuteCommandProvider: protocol.ExecuteCommandOptions{
	Commands: options.SupportedCommands,
	},
	FoldingRangeProvider: true,
	HoverProvider: true,
	DocumentHighlightProvider: true,
	DocumentLinkProvider: protocol.DocumentLinkOptions{},
	ReferencesProvider: true,
	RenameProvider: renameOpts,
	SignatureHelpProvider: protocol.SignatureHelpOptions{
	TriggerCharacters: []string{"(", ","},
	},
	TextDocumentSync: &protocol.TextDocumentSyncOptions{
	Change: protocol.Incremental,
	OpenClose: true,
	Save: protocol.SaveOptions{
	IncludeText: false,
	},
	},
	Workspace: protocol.WorkspaceGn{
	WorkspaceFolders: protocol.WorkspaceFoldersGn{
	Supported: true,
	ChangeNotifications: "workspace/didChangeWorkspaceFolders",
	},
	},
	},
	ServerInfo: struct {
	Name string `json:"name"`
	Version string `json:"version,omitempty"`
	}{
	Name: "gopls",
	Version: goplsVer.String(),
	},
	}, nil
	}

	func (s Server) initialized(ctx context.Context, params protocol.InitializedParams) error {
	s.stateMu.Lock()
	if s.state >= serverInitialized {
	defer s.stateMu.Unlock()
	return fmt.Errorf("%w: initalized called while server in %v state", jsonrpc2.ErrInvalidRequest, s.state)
	}
	s.state = serverInitialized
	s.stateMu.Unlock()

	options := s.session.Options()
	defer func() { s.session.SetOptions(options) }()

	var registrations []protocol.Registration
	if options.ConfigurationSupported && options.DynamicConfigurationSupported {
	registrations = append(registrations,
	protocol.Registration{
	ID: "workspace/didChangeConfiguration",
	Method: "workspace/didChangeConfiguration",
	},
	protocol.Registration{
	ID: "workspace/didChangeWorkspaceFolders",
	Method: "workspace/didChangeWorkspaceFolders",
	},
	)
	}

	// TODO: this event logging may be unnecessary.
	// The version info is included in the initialize response.
	buf := &bytes.Buffer{}
	debug.PrintVersionInfo(ctx, buf, true, debug.PlainText)
	event.Log(ctx, buf.String())

	if err := s.addFolders(ctx, s.pendingFolders); err != nil {
	return err
	}
	s.pendingFolders = nil

	if len(registrations) > 0 {
	if err := s.client.RegisterCapability(ctx, &protocol.RegistrationParams{
	Registrations: registrations,
	}); err != nil {
	return err
	}
	}
	return nil
	}

	func (s *Server) addFolders(ctx context.Context, folders []protocol.WorkspaceFolder) error {
	originalViews := len(s.session.Views())
	viewErrors := make(map[span.URI]error)

	var wg sync.WaitGroup
	if s.session.Options().VerboseWorkDoneProgress {
	work := s.progress.start(ctx, DiagnosticWorkTitle(FromInitialWorkspaceLoad), "Calculating diagnostics for initial workspace load...", nil, nil)
	defer func() {
	go func() {
	wg.Wait()
	work.end(ctx, "Done.")
	}()
	}()
	}
	dirsToWatch := map[span.URI]struct{}{}
	for _, folder := range folders {
	uri := span.URIFromURI(folder.URI)
	view, snapshot, release, err := s.addView(ctx, folder.Name, uri)
	if err != nil {
	viewErrors[uri] = err
	continue
	}
	for _, dir := range snapshot.WorkspaceDirectories(ctx) {
	dirsToWatch[dir] = struct{}{}
	}

	// Print each view's environment.
	buf := &bytes.Buffer{}
	if err := view.WriteEnv(ctx, buf); err != nil {
	event.Error(ctx, "failed to write environment", err, tag.Directory.Of(view.Folder().Filename()))
	continue
	}
	event.Log(ctx, buf.String())

	// Diagnose the newly created view.
	wg.Add(1)
	go func() {
	s.diagnoseDetached(snapshot)
	release()
	wg.Done()
	}()
	}
	// Register for file watching notifications, if they are supported.
	s.watchedDirectoriesMu.Lock()
	err := s.registerWatchedDirectoriesLocked(ctx, dirsToWatch)
	s.watchedDirectoriesMu.Unlock()
	if err != nil {
	return err
	}
	if len(viewErrors) > 0 {
	errMsg := fmt.Sprintf("Error loading workspace folders (expected %v, got %v)\n", len(folders), len(s.session.Views())-originalViews)
	for uri, err := range viewErrors {
	errMsg += fmt.Sprintf("failed to load view for %s: %v\n", uri, err)
	}
	return s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
	Type: protocol.Error,
	Message: errMsg,
	})
	}
	return nil
	}

	// updateWatchedDirectories compares the current set of directories to watch
	// with the previously registered set of directories. If the set of directories
	// has changed, we unregister and re-register for file watching notifications.
	// updatedSnapshots is the set of snapshots that have been updated.
	func (s *Server) updateWatchedDirectories(ctx context.Context, updatedSnapshots []source.Snapshot) error {
	dirsToWatch := map[span.URI]struct{}{}
	seenViews := map[source.View]struct{}{}

	// Collect all of the workspace directories from the updated snapshots.
	for _, snapshot := range updatedSnapshots {
	seenViews[snapshot.View()] = struct{}{}
	for _, dir := range snapshot.WorkspaceDirectories(ctx) {
	dirsToWatch[dir] = struct{}{}
	}
	}
	// Not all views were necessarily updated, so check the remaining views.
	for _, view := range s.session.Views() {
	if _, ok := seenViews[view]; ok {
	continue
	}
	snapshot, release := view.Snapshot(ctx)
	for _, dir := range snapshot.WorkspaceDirectories(ctx) {
	dirsToWatch[dir] = struct{}{}
	}
	release()
	}

	s.watchedDirectoriesMu.Lock()
	defer s.watchedDirectoriesMu.Unlock()

	// Nothing to do if the set of workspace directories is unchanged.
	if equalURISet(s.watchedDirectories, dirsToWatch) {
	return nil
	}

	// If the set of directories to watch has changed, register the updates and
	// unregister the previously watched directories. This ordering avoids a
	// period where no files are being watched. Still, if a user makes on-disk
	// changes before these updates are complete, we may miss them for the new
	// directories.
	if s.watchRegistrationCount > 0 {
	prevID := s.watchRegistrationCount - 1
	if err := s.registerWatchedDirectoriesLocked(ctx, dirsToWatch); err != nil {
	return err
	}
	return s.client.UnregisterCapability(ctx, &protocol.UnregistrationParams{
	Unregisterations: []protocol.Unregistration{{
	ID: watchedFilesCapabilityID(prevID),
	Method: "workspace/didChangeWatchedFiles",
	}},
	})
	}
	return nil
	}

	func watchedFilesCapabilityID(id uint64) string {
	return fmt.Sprintf("workspace/didChangeWatchedFiles-%d", id)
	}

	func equalURISet(m1, m2 map[span.URI]struct{}) bool {
	if len(m1) != len(m2) {
	return false
	}
	for k := range m1 {
	_, ok := m2[k]
	if !ok {
	return false
	}
	}
	return true
	}

	// registerWatchedDirectoriesLocked sends the workspace/didChangeWatchedFiles
	// registrations to the client and updates s.watchedDirectories.
	func (s *Server) registerWatchedDirectoriesLocked(ctx context.Context, dirs map[span.URI]struct{}) error {
	if !s.session.Options().DynamicWatchedFilesSupported {
	return nil
	}
	for k := range s.watchedDirectories {
	delete(s.watchedDirectories, k)
	}
	var watchers []protocol.FileSystemWatcher
	for dir := range dirs {
	watchers = append(watchers, protocol.FileSystemWatcher{
	GlobPattern: fmt.Sprintf("%s/*/.{go,mod,sum}", dir),
	Kind: float64(protocol.WatchChange + protocol.WatchDelete + protocol.WatchCreate),
	})
	}
	if err := s.client.RegisterCapability(ctx, &protocol.RegistrationParams{
	Registrations: []protocol.Registration{{
	ID: watchedFilesCapabilityID(s.watchRegistrationCount),
	Method: "workspace/didChangeWatchedFiles",
	RegisterOptions: protocol.DidChangeWatchedFilesRegistrationOptions{
	Watchers: watchers,
	},
	}},
	}); err != nil {
	return err
	}
	s.watchRegistrationCount++

	for dir := range dirs {
	s.watchedDirectories[dir] = struct{}{}
	}
	return nil
	}

	func (s Server) fetchConfig(ctx context.Context, name string, folder span.URI, o source.Options) error {
	if !s.session.Options().ConfigurationSupported {
	return nil
	}
	v := protocol.ParamConfiguration{
	ConfigurationParams: protocol.ConfigurationParams{
	Items: []protocol.ConfigurationItem{{
	ScopeURI: string(folder),
	Section: "gopls",
	}, {
	ScopeURI: string(folder),
	Section: fmt.Sprintf("gopls-%s", name),
	}},
	},
	}
	configs, err := s.client.Configuration(ctx, &v)
	if err != nil {
	return fmt.Errorf("failed to get workspace configuration from client (%s): %v", folder, err)
	}
	for _, config := range configs {
	if err := s.handleOptionResults(ctx, source.SetOptions(o, config)); err != nil {
	return err
	}
	}
	return nil
	}

	func (s *Server) handleOptionResults(ctx context.Context, results source.OptionResults) error {
	for _, result := range results {
	if result.Error != nil {
	if err := s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
	Type: protocol.Error,
	Message: result.Error.Error(),
	}); err != nil {
	return err
	}
	}
	switch result.State {
	case source.OptionUnexpected:
	if err := s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
	Type: protocol.Error,
	Message: fmt.Sprintf("unexpected config %s", result.Name),
	}); err != nil {
	return err
	}
	case source.OptionDeprecated:
	msg := fmt.Sprintf("config %s is deprecated", result.Name)
	if result.Replacement != "" {
	msg = fmt.Sprintf("%s, use %s instead", msg, result.Replacement)
	}
	if err := s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
	Type: protocol.Warning,
	Message: msg,
	}); err != nil {
	return err
	}
	}
	}
	return nil
	}

	// beginFileRequest checks preconditions for a file-oriented request and routes
	// it to a snapshot.
	// We don't want to return errors for benign conditions like wrong file type,
	// so callers should do if !ok { return err } rather than if err != nil.
	func (s *Server) beginFileRequest(ctx context.Context, pURI protocol.DocumentURI, expectKind source.FileKind) (source.Snapshot, source.VersionedFileHandle, bool, func(), error) {
	uri := pURI.SpanURI()
	if !uri.IsFile() {
	// Not a file URI. Stop processing the request, but don't return an error.
	return nil, nil, false, func() {}, nil
	}
	view, err := s.session.ViewOf(uri)
	if err != nil {
	return nil, nil, false, func() {}, err
	}
	snapshot, release := view.Snapshot(ctx)
	fh, err := snapshot.GetFile(ctx, uri)
	if err != nil {
	release()
	return nil, nil, false, func() {}, err
	}
	if expectKind != source.UnknownKind && fh.Kind() != expectKind {
	// Wrong kind of file. Nothing to do.
	release()
	return nil, nil, false, func() {}, nil
	}
	return snapshot, fh, true, release, nil
	}

	func (s *Server) shutdown(ctx context.Context) error {
	s.stateMu.Lock()
	defer s.stateMu.Unlock()
	if s.state < serverInitialized {
	event.Log(ctx, "server shutdown without initialization")
	}
	if s.state != serverShutDown {
	// drop all the active views
	s.session.Shutdown(ctx)
	s.state = serverShutDown
	}
	return nil
	}

	func (s *Server) exit(ctx context.Context) error {
	s.stateMu.Lock()
	defer s.stateMu.Unlock()

	// TODO: We need a better way to find the conn close method.
	s.client.(io.Closer).Close()

	if s.state != serverShutDown {
	// TODO: We should be able to do better than this.
	os.Exit(1)
	}
	// we don't terminate the process on a normal exit, we just allow it to
	// close naturally if needed after the connection is closed.
	return nil
	}