gopls/internal/lsp/text_synchronization.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"
 	"errors"
 	"fmt"
 	"path/filepath"
 	"sync"

 	"golang.org/x/tools/gopls/internal/lsp/protocol"
 	"golang.org/x/tools/gopls/internal/lsp/source"
 	"golang.org/x/tools/gopls/internal/span"
 	"golang.org/x/tools/internal/jsonrpc2"
 )

 // ModificationSource identifies the originating cause of a file modification.
 type ModificationSource int

 const (
 	// FromDidOpen is a file modification caused by opening a file.
 	FromDidOpen = ModificationSource(iota)

 	// FromDidChange is a file modification caused by changing a file.
 	FromDidChange

 	// FromDidChangeWatchedFiles is a file modification caused by a change to a
 	// watched file.
 	FromDidChangeWatchedFiles

 	// FromDidSave is a file modification caused by a file save.
 	FromDidSave

 	// FromDidClose is a file modification caused by closing a file.
 	FromDidClose

 	// TODO: add FromDidChangeConfiguration, once configuration changes cause a
 	// new snapshot to be created.

 	// FromRegenerateCgo refers to file modifications caused by regenerating
 	// the cgo sources for the workspace.
 	FromRegenerateCgo

 	// FromInitialWorkspaceLoad refers to the loading of all packages in the
 	// workspace when the view is first created.
 	FromInitialWorkspaceLoad
 )

 func (m ModificationSource) String() string {
 	switch m {
 	case FromDidOpen:
 		return "opened files"
 	case FromDidChange:
 		return "changed files"
 	case FromDidChangeWatchedFiles:
 		return "files changed on disk"
 	case FromDidSave:
 		return "saved files"
 	case FromDidClose:
 		return "close files"
 	case FromRegenerateCgo:
 		return "regenerate cgo"
 	case FromInitialWorkspaceLoad:
 		return "initial workspace load"
 	default:
 		return "unknown file modification"
 	}
 }

 func (s *Server) didOpen(ctx context.Context, params *protocol.DidOpenTextDocumentParams) error {
 	uri := params.TextDocument.URI.SpanURI()
 	if !uri.IsFile() {
 		return nil
 	}
 	// There may not be any matching view in the current session. If that's
 	// the case, try creating a new view based on the opened file path.
 	//
 	// TODO(rstambler): This seems like it would continuously add new
 	// views, but it won't because ViewOf only returns an error when there
 	// are no views in the session. I don't know if that logic should go
 	// here, or if we can continue to rely on that implementation detail.
 	if _, err := s.session.ViewOf(uri); err != nil {
 		dir := filepath.Dir(uri.Filename())
 		if err := s.addFolders(ctx, []protocol.WorkspaceFolder{{
 			URI:  string(protocol.URIFromPath(dir)),
 			Name: filepath.Base(dir),
 		}}); err != nil {
 			return err
 		}
 	}
 	return s.didModifyFiles(ctx, []source.FileModification{{
 		URI:        uri,
 		Action:     source.Open,
 		Version:    params.TextDocument.Version,
 		Text:       []byte(params.TextDocument.Text),
 		LanguageID: params.TextDocument.LanguageID,
 	}}, FromDidOpen)
 }

 func (s *Server) didChange(ctx context.Context, params *protocol.DidChangeTextDocumentParams) error {
 	uri := params.TextDocument.URI.SpanURI()
 	if !uri.IsFile() {
 		return nil
 	}

 	text, err := s.changedText(ctx, uri, params.ContentChanges)
 	if err != nil {
 		return err
 	}
 	c := source.FileModification{
 		URI:     uri,
 		Action:  source.Change,
 		Version: params.TextDocument.Version,
 		Text:    text,
 	}
 	if err := s.didModifyFiles(ctx, []source.FileModification{c}, FromDidChange); err != nil {
 		return err
 	}
 	return s.warnAboutModifyingGeneratedFiles(ctx, uri)
 }

 // warnAboutModifyingGeneratedFiles shows a warning if a user tries to edit a
 // generated file for the first time.
 func (s *Server) warnAboutModifyingGeneratedFiles(ctx context.Context, uri span.URI) error {
 	s.changedFilesMu.Lock()
 	_, ok := s.changedFiles[uri]
 	if !ok {
 		s.changedFiles[uri] = struct{}{}
 	}
 	s.changedFilesMu.Unlock()

 	// This file has already been edited before.
 	if ok {
 		return nil
 	}

 	// Ideally, we should be able to specify that a generated file should
 	// be opened as read-only. Tell the user that they should not be
 	// editing a generated file.
 	view, err := s.session.ViewOf(uri)
 	if err != nil {
 		return err
 	}
 	snapshot, release, err := view.Snapshot()
 	if err != nil {
 		return err
 	}
 	isGenerated := source.IsGenerated(ctx, snapshot, uri)
 	release()

 	if !isGenerated {
 		return nil
 	}
 	return s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
 		Message: fmt.Sprintf("Do not edit this file! %s is a generated file.", uri.Filename()),
 		Type:    protocol.Warning,
 	})
 }

 func (s *Server) didChangeWatchedFiles(ctx context.Context, params *protocol.DidChangeWatchedFilesParams) error {
 	var modifications []source.FileModification
 	for _, change := range params.Changes {
 		uri := change.URI.SpanURI()
 		if !uri.IsFile() {
 			continue
 		}
 		action := changeTypeToFileAction(change.Type)
 		modifications = append(modifications, source.FileModification{
 			URI:    uri,
 			Action: action,
 			OnDisk: true,
 		})
 	}
 	return s.didModifyFiles(ctx, modifications, FromDidChangeWatchedFiles)
 }

 func (s *Server) didSave(ctx context.Context, params *protocol.DidSaveTextDocumentParams) error {
 	uri := params.TextDocument.URI.SpanURI()
 	if !uri.IsFile() {
 		return nil
 	}
 	c := source.FileModification{
 		URI:    uri,
 		Action: source.Save,
 	}
 	if params.Text != nil {
 		c.Text = []byte(*params.Text)
 	}
 	return s.didModifyFiles(ctx, []source.FileModification{c}, FromDidSave)
 }

 func (s *Server) didClose(ctx context.Context, params *protocol.DidCloseTextDocumentParams) error {
 	uri := params.TextDocument.URI.SpanURI()
 	if !uri.IsFile() {
 		return nil
 	}
 	return s.didModifyFiles(ctx, []source.FileModification{
 		{
 			URI:     uri,
 			Action:  source.Close,
 			Version: -1,
 			Text:    nil,
 		},
 	}, FromDidClose)
 }

 func (s *Server) didModifyFiles(ctx context.Context, modifications []source.FileModification, cause ModificationSource) error {
 	// wg guards two conditions:
 	//  1. didModifyFiles is complete
 	//  2. the goroutine diagnosing changes on behalf of didModifyFiles is
 	//     complete, if it was started
 	//
 	// Both conditions must be satisfied for the purpose of testing: we don't
 	// want to observe the completion of change processing until we have received
 	// all diagnostics as well as all server->client notifications done on behalf
 	// of this function.
 	var wg sync.WaitGroup
 	wg.Add(1)
 	defer wg.Done()

 	if s.session.Options().VerboseWorkDoneProgress {
 		work := s.progress.Start(ctx, DiagnosticWorkTitle(cause), "Calculating file diagnostics...", nil, nil)
 		go func() {
 			wg.Wait()
 			work.End(ctx, "Done.")
 		}()
 	}

 	onDisk := cause == FromDidChangeWatchedFiles

 	s.stateMu.Lock()
 	if s.state >= serverShutDown {
 		// This state check does not prevent races below, and exists only to
 		// produce a better error message. The actual race to the cache should be
 		// guarded by Session.viewMu.
 		s.stateMu.Unlock()
 		return errors.New("server is shut down")
 	}
 	s.stateMu.Unlock()

 	// If the set of changes included directories, expand those directories
 	// to their files.
 	modifications = s.session.ExpandModificationsToDirectories(ctx, modifications)

 	// Build a lookup map for file modifications, so that we can later join
 	// with the snapshot file associations.
 	modMap := make(map[span.URI]source.FileModification)
 	for _, mod := range modifications {
 		modMap[mod.URI] = mod
 	}

 	snapshots, release, err := s.session.DidModifyFiles(ctx, modifications)
 	if err != nil {
 		return err
 	}

 	// golang/go#50267: diagnostics should be re-sent after an open or close. For
 	// some clients, it may be helpful to re-send after each change.
 	for snapshot, uris := range snapshots {
 		for _, uri := range uris {
 			mod := modMap[uri]
 			if snapshot.View().Options().ChattyDiagnostics || mod.Action == source.Open || mod.Action == source.Close {
 				s.mustPublishDiagnostics(uri)
 			}
 		}
 	}

 	wg.Add(1)
 	go func() {
 		s.diagnoseSnapshots(snapshots, onDisk)
 		release()
 		wg.Done()
 	}()

 	// After any file modifications, we need to update our watched files,
 	// in case something changed. Compute the new set of directories to watch,
 	// and if it differs from the current set, send updated registrations.
 	return s.updateWatchedDirectories(ctx)
 }

 // DiagnosticWorkTitle returns the title of the diagnostic work resulting from a
 // file change originating from the given cause.
 func DiagnosticWorkTitle(cause ModificationSource) string {
 	return fmt.Sprintf("diagnosing %v", cause)
 }

 func (s *Server) changedText(ctx context.Context, uri span.URI, changes []protocol.TextDocumentContentChangeEvent) ([]byte, error) {
 	if len(changes) == 0 {
 		return nil, fmt.Errorf("%w: no content changes provided", jsonrpc2.ErrInternal)
 	}

 	// Check if the client sent the full content of the file.
 	// We accept a full content change even if the server expected incremental changes.
 	if len(changes) == 1 && changes[0].Range == nil && changes[0].RangeLength == 0 {
 		return []byte(changes[0].Text), nil
 	}
 	return s.applyIncrementalChanges(ctx, uri, changes)
 }

 func (s *Server) applyIncrementalChanges(ctx context.Context, uri span.URI, changes []protocol.TextDocumentContentChangeEvent) ([]byte, error) {
 	fh, err := s.session.GetFile(ctx, uri)
 	if err != nil {
 		return nil, err
 	}
 	content, err := fh.Read()
 	if err != nil {
 		return nil, fmt.Errorf("%w: file not found (%v)", jsonrpc2.ErrInternal, err)
 	}
 	for _, change := range changes {
 		// TODO(adonovan): refactor to use diff.Apply, which is robust w.r.t.
 		// out-of-order or overlapping changes---and much more efficient.

 		// Make sure to update mapper along with the content.
 		m := protocol.NewMapper(uri, content)
 		if change.Range == nil {
 			return nil, fmt.Errorf("%w: unexpected nil range for change", jsonrpc2.ErrInternal)
 		}
 		spn, err := m.RangeSpan(*change.Range)
 		if err != nil {
 			return nil, err
 		}
 		start, end := spn.Start().Offset(), spn.End().Offset()
 		if end < start {
 			return nil, fmt.Errorf("%w: invalid range for content change", jsonrpc2.ErrInternal)
 		}
 		var buf bytes.Buffer
 		buf.Write(content[:start])
 		buf.WriteString(change.Text)
 		buf.Write(content[end:])
 		content = buf.Bytes()
 	}
 	return content, nil
 }

 func changeTypeToFileAction(ct protocol.FileChangeType) source.FileAction {
 	switch ct {
 	case protocol.Changed:
 		return source.Change
 	case protocol.Created:
 		return source.Create
 	case protocol.Deleted:
 		return source.Delete
 	}
 	return source.UnknownFileAction
 }
	// 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"
	"errors"
	"fmt"
	"path/filepath"
	"sync"

	"golang.org/x/tools/gopls/internal/lsp/protocol"
	"golang.org/x/tools/gopls/internal/lsp/source"
	"golang.org/x/tools/gopls/internal/span"
	"golang.org/x/tools/internal/jsonrpc2"
	)

	// ModificationSource identifies the originating cause of a file modification.
	type ModificationSource int

	const (
	// FromDidOpen is a file modification caused by opening a file.
	FromDidOpen = ModificationSource(iota)

	// FromDidChange is a file modification caused by changing a file.
	FromDidChange

	// FromDidChangeWatchedFiles is a file modification caused by a change to a
	// watched file.
	FromDidChangeWatchedFiles

	// FromDidSave is a file modification caused by a file save.
	FromDidSave

	// FromDidClose is a file modification caused by closing a file.
	FromDidClose

	// TODO: add FromDidChangeConfiguration, once configuration changes cause a
	// new snapshot to be created.

	// FromRegenerateCgo refers to file modifications caused by regenerating
	// the cgo sources for the workspace.
	FromRegenerateCgo

	// FromInitialWorkspaceLoad refers to the loading of all packages in the
	// workspace when the view is first created.
	FromInitialWorkspaceLoad
	)

	func (m ModificationSource) String() string {
	switch m {
	case FromDidOpen:
	return "opened files"
	case FromDidChange:
	return "changed files"
	case FromDidChangeWatchedFiles:
	return "files changed on disk"
	case FromDidSave:
	return "saved files"
	case FromDidClose:
	return "close files"
	case FromRegenerateCgo:
	return "regenerate cgo"
	case FromInitialWorkspaceLoad:
	return "initial workspace load"
	default:
	return "unknown file modification"
	}
	}

	func (s Server) didOpen(ctx context.Context, params protocol.DidOpenTextDocumentParams) error {
	uri := params.TextDocument.URI.SpanURI()
	if !uri.IsFile() {
	return nil
	}
	// There may not be any matching view in the current session. If that's
	// the case, try creating a new view based on the opened file path.
	//
	// TODO(rstambler): This seems like it would continuously add new
	// views, but it won't because ViewOf only returns an error when there
	// are no views in the session. I don't know if that logic should go
	// here, or if we can continue to rely on that implementation detail.
	if _, err := s.session.ViewOf(uri); err != nil {
	dir := filepath.Dir(uri.Filename())
	if err := s.addFolders(ctx, []protocol.WorkspaceFolder{{
	URI: string(protocol.URIFromPath(dir)),
	Name: filepath.Base(dir),
	}}); err != nil {
	return err
	}
	}
	return s.didModifyFiles(ctx, []source.FileModification{{
	URI: uri,
	Action: source.Open,
	Version: params.TextDocument.Version,
	Text: []byte(params.TextDocument.Text),
	LanguageID: params.TextDocument.LanguageID,
	}}, FromDidOpen)
	}

	func (s Server) didChange(ctx context.Context, params protocol.DidChangeTextDocumentParams) error {
	uri := params.TextDocument.URI.SpanURI()
	if !uri.IsFile() {
	return nil
	}

	text, err := s.changedText(ctx, uri, params.ContentChanges)
	if err != nil {
	return err
	}
	c := source.FileModification{
	URI: uri,
	Action: source.Change,
	Version: params.TextDocument.Version,
	Text: text,
	}
	if err := s.didModifyFiles(ctx, []source.FileModification{c}, FromDidChange); err != nil {
	return err
	}
	return s.warnAboutModifyingGeneratedFiles(ctx, uri)
	}

	// warnAboutModifyingGeneratedFiles shows a warning if a user tries to edit a
	// generated file for the first time.
	func (s *Server) warnAboutModifyingGeneratedFiles(ctx context.Context, uri span.URI) error {
	s.changedFilesMu.Lock()
	_, ok := s.changedFiles[uri]
	if !ok {
	s.changedFiles[uri] = struct{}{}
	}
	s.changedFilesMu.Unlock()

	// This file has already been edited before.
	if ok {
	return nil
	}

	// Ideally, we should be able to specify that a generated file should
	// be opened as read-only. Tell the user that they should not be
	// editing a generated file.
	view, err := s.session.ViewOf(uri)
	if err != nil {
	return err
	}
	snapshot, release, err := view.Snapshot()
	if err != nil {
	return err
	}
	isGenerated := source.IsGenerated(ctx, snapshot, uri)
	release()

	if !isGenerated {
	return nil
	}
	return s.client.ShowMessage(ctx, &protocol.ShowMessageParams{
	Message: fmt.Sprintf("Do not edit this file! %s is a generated file.", uri.Filename()),
	Type: protocol.Warning,
	})
	}

	func (s Server) didChangeWatchedFiles(ctx context.Context, params protocol.DidChangeWatchedFilesParams) error {
	var modifications []source.FileModification
	for _, change := range params.Changes {
	uri := change.URI.SpanURI()
	if !uri.IsFile() {
	continue
	}
	action := changeTypeToFileAction(change.Type)
	modifications = append(modifications, source.FileModification{
	URI: uri,
	Action: action,
	OnDisk: true,
	})
	}
	return s.didModifyFiles(ctx, modifications, FromDidChangeWatchedFiles)
	}

	func (s Server) didSave(ctx context.Context, params protocol.DidSaveTextDocumentParams) error {
	uri := params.TextDocument.URI.SpanURI()
	if !uri.IsFile() {
	return nil
	}
	c := source.FileModification{
	URI: uri,
	Action: source.Save,
	}
	if params.Text != nil {
	c.Text = []byte(*params.Text)
	}
	return s.didModifyFiles(ctx, []source.FileModification{c}, FromDidSave)
	}

	func (s Server) didClose(ctx context.Context, params protocol.DidCloseTextDocumentParams) error {
	uri := params.TextDocument.URI.SpanURI()
	if !uri.IsFile() {
	return nil
	}
	return s.didModifyFiles(ctx, []source.FileModification{
	{
	URI: uri,
	Action: source.Close,
	Version: -1,
	Text: nil,
	},
	}, FromDidClose)
	}

	func (s *Server) didModifyFiles(ctx context.Context, modifications []source.FileModification, cause ModificationSource) error {
	// wg guards two conditions:
	// 1. didModifyFiles is complete
	// 2. the goroutine diagnosing changes on behalf of didModifyFiles is
	// complete, if it was started
	//
	// Both conditions must be satisfied for the purpose of testing: we don't
	// want to observe the completion of change processing until we have received
	// all diagnostics as well as all server->client notifications done on behalf
	// of this function.
	var wg sync.WaitGroup
	wg.Add(1)
	defer wg.Done()

	if s.session.Options().VerboseWorkDoneProgress {
	work := s.progress.Start(ctx, DiagnosticWorkTitle(cause), "Calculating file diagnostics...", nil, nil)
	go func() {
	wg.Wait()
	work.End(ctx, "Done.")
	}()
	}

	onDisk := cause == FromDidChangeWatchedFiles

	s.stateMu.Lock()
	if s.state >= serverShutDown {
	// This state check does not prevent races below, and exists only to
	// produce a better error message. The actual race to the cache should be
	// guarded by Session.viewMu.
	s.stateMu.Unlock()
	return errors.New("server is shut down")
	}
	s.stateMu.Unlock()

	// If the set of changes included directories, expand those directories
	// to their files.
	modifications = s.session.ExpandModificationsToDirectories(ctx, modifications)

	// Build a lookup map for file modifications, so that we can later join
	// with the snapshot file associations.
	modMap := make(map[span.URI]source.FileModification)
	for _, mod := range modifications {
	modMap[mod.URI] = mod
	}

	snapshots, release, err := s.session.DidModifyFiles(ctx, modifications)
	if err != nil {
	return err
	}

	// golang/go#50267: diagnostics should be re-sent after an open or close. For
	// some clients, it may be helpful to re-send after each change.
	for snapshot, uris := range snapshots {
	for _, uri := range uris {
	mod := modMap[uri]
	if snapshot.View().Options().ChattyDiagnostics \|\| mod.Action == source.Open \|\| mod.Action == source.Close {
	s.mustPublishDiagnostics(uri)
	}
	}
	}

	wg.Add(1)
	go func() {
	s.diagnoseSnapshots(snapshots, onDisk)
	release()
	wg.Done()
	}()

	// After any file modifications, we need to update our watched files,
	// in case something changed. Compute the new set of directories to watch,
	// and if it differs from the current set, send updated registrations.
	return s.updateWatchedDirectories(ctx)
	}

	// DiagnosticWorkTitle returns the title of the diagnostic work resulting from a
	// file change originating from the given cause.
	func DiagnosticWorkTitle(cause ModificationSource) string {
	return fmt.Sprintf("diagnosing %v", cause)
	}

	func (s *Server) changedText(ctx context.Context, uri span.URI, changes []protocol.TextDocumentContentChangeEvent) ([]byte, error) {
	if len(changes) == 0 {
	return nil, fmt.Errorf("%w: no content changes provided", jsonrpc2.ErrInternal)
	}

	// Check if the client sent the full content of the file.
	// We accept a full content change even if the server expected incremental changes.
	if len(changes) == 1 && changes[0].Range == nil && changes[0].RangeLength == 0 {
	return []byte(changes[0].Text), nil
	}
	return s.applyIncrementalChanges(ctx, uri, changes)
	}

	func (s *Server) applyIncrementalChanges(ctx context.Context, uri span.URI, changes []protocol.TextDocumentContentChangeEvent) ([]byte, error) {
	fh, err := s.session.GetFile(ctx, uri)
	if err != nil {
	return nil, err
	}
	content, err := fh.Read()
	if err != nil {
	return nil, fmt.Errorf("%w: file not found (%v)", jsonrpc2.ErrInternal, err)
	}
	for _, change := range changes {
	// TODO(adonovan): refactor to use diff.Apply, which is robust w.r.t.
	// out-of-order or overlapping changes---and much more efficient.

	// Make sure to update mapper along with the content.
	m := protocol.NewMapper(uri, content)
	if change.Range == nil {
	return nil, fmt.Errorf("%w: unexpected nil range for change", jsonrpc2.ErrInternal)
	}
	spn, err := m.RangeSpan(*change.Range)
	if err != nil {
	return nil, err
	}
	start, end := spn.Start().Offset(), spn.End().Offset()
	if end < start {
	return nil, fmt.Errorf("%w: invalid range for content change", jsonrpc2.ErrInternal)
	}
	var buf bytes.Buffer
	buf.Write(content[:start])
	buf.WriteString(change.Text)
	buf.Write(content[end:])
	content = buf.Bytes()
	}
	return content, nil
	}

	func changeTypeToFileAction(ct protocol.FileChangeType) source.FileAction {
	switch ct {
	case protocol.Changed:
	return source.Change
	case protocol.Created:
	return source.Create
	case protocol.Deleted:
	return source.Delete
	}
	return source.UnknownFileAction
	}