internal/lsp/cache/session.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 cache

 import (
 	"context"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"

 	"golang.org/x/tools/internal/lsp/debug"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/lsp/telemetry"
 	"golang.org/x/tools/internal/span"
 	"golang.org/x/tools/internal/telemetry/log"
 	"golang.org/x/tools/internal/telemetry/trace"
 	"golang.org/x/tools/internal/xcontext"
 	errors "golang.org/x/xerrors"
 )

 type session struct {
 	cache *cache
 	id    string

 	options source.Options

 	viewMu  sync.Mutex
 	views   []*view
 	viewMap map[span.URI]source.View

 	overlayMu sync.Mutex
 	overlays  map[span.URI]*overlay

 	openFiles     sync.Map
 	filesWatchMap *WatchMap
 }

 type overlay struct {
 	session *session
 	uri     span.URI
 	data    []byte
 	hash    string
 	kind    source.FileKind

 	// sameContentOnDisk is true if a file has been saved on disk,
 	// and therefore does not need to be part of the overlay sent to go/packages.
 	sameContentOnDisk bool

 	// unchanged is true if a file has not yet been edited.
 	unchanged bool
 }

 func (s *session) Options() source.Options {
 	return s.options
 }

 func (s *session) SetOptions(options source.Options) {
 	s.options = options
 }

 func (s *session) Shutdown(ctx context.Context) {
 	s.viewMu.Lock()
 	defer s.viewMu.Unlock()
 	for _, view := range s.views {
 		view.shutdown(ctx)
 	}
 	s.views = nil
 	s.viewMap = nil
 	debug.DropSession(debugSession{s})
 }

 func (s *session) Cache() source.Cache {
 	return s.cache
 }

 func (s *session) NewView(ctx context.Context, name string, folder span.URI, options source.Options) source.View {
 	index := atomic.AddInt64(&viewIndex, 1)
 	s.viewMu.Lock()
 	defer s.viewMu.Unlock()
 	// We want a true background context and not a detached context here
 	// the spans need to be unrelated and no tag values should pollute it.
 	baseCtx := trace.Detach(xcontext.Detach(ctx))
 	backgroundCtx, cancel := context.WithCancel(baseCtx)
 	v := &view{
 		session:       s,
 		id:            strconv.FormatInt(index, 10),
 		options:       options,
 		baseCtx:       baseCtx,
 		backgroundCtx: backgroundCtx,
 		cancel:        cancel,
 		name:          name,
 		folder:        folder,
 		filesByURI:    make(map[span.URI]viewFile),
 		filesByBase:   make(map[string][]viewFile),
 		mcache: &metadataCache{
 			packages: make(map[packageID]*metadata),
 		},
 		ignoredURIs: make(map[span.URI]struct{}),
 	}
 	// Preemptively build the builtin package,
 	// so we immediately add builtin.go to the list of ignored files.
 	v.buildBuiltinPkg(ctx)

 	s.views = append(s.views, v)
 	// we always need to drop the view map
 	s.viewMap = make(map[span.URI]source.View)
 	debug.AddView(debugView{v})
 	return v
 }

 // View returns the view by name.
 func (s *session) View(name string) source.View {
 	s.viewMu.Lock()
 	defer s.viewMu.Unlock()
 	for _, view := range s.views {
 		if view.Name() == name {
 			return view
 		}
 	}
 	return nil
 }

 // ViewOf returns a view corresponding to the given URI.
 // If the file is not already associated with a view, pick one using some heuristics.
 func (s *session) ViewOf(uri span.URI) source.View {
 	s.viewMu.Lock()
 	defer s.viewMu.Unlock()

 	// Check if we already know this file.
 	if v, found := s.viewMap[uri]; found {
 		return v
 	}
 	// Pick the best view for this file and memoize the result.
 	v := s.bestView(uri)
 	s.viewMap[uri] = v
 	return v
 }

 func (s *session) Views() []source.View {
 	s.viewMu.Lock()
 	defer s.viewMu.Unlock()
 	result := make([]source.View, len(s.views))
 	for i, v := range s.views {
 		result[i] = v
 	}
 	return result
 }

 // bestView finds the best view to associate a given URI with.
 // viewMu must be held when calling this method.
 func (s *session) bestView(uri span.URI) source.View {
 	// we need to find the best view for this file
 	var longest source.View
 	for _, view := range s.views {
 		if longest != nil && len(longest.Folder()) > len(view.Folder()) {
 			continue
 		}
 		if strings.HasPrefix(string(uri), string(view.Folder())) {
 			longest = view
 		}
 	}
 	if longest != nil {
 		return longest
 	}
 	// TODO: are there any more heuristics we can use?
 	return s.views[0]
 }

 func (s *session) removeView(ctx context.Context, view *view) error {
 	s.viewMu.Lock()
 	defer s.viewMu.Unlock()
 	// we always need to drop the view map
 	s.viewMap = make(map[span.URI]source.View)
 	for i, v := range s.views {
 		if view == v {
 			// delete this view... we don't care about order but we do want to make
 			// sure we can garbage collect the view
 			s.views[i] = s.views[len(s.views)-1]
 			s.views[len(s.views)-1] = nil
 			s.views = s.views[:len(s.views)-1]
 			v.shutdown(ctx)
 			return nil
 		}
 	}
 	return errors.Errorf("view %s for %v not found", view.Name(), view.Folder())
 }

 // TODO: Propagate the language ID through to the view.
 func (s *session) DidOpen(ctx context.Context, uri span.URI, _ source.FileKind, text []byte) {
 	ctx = telemetry.File.With(ctx, uri)

 	// Files with _ prefixes are ignored.
 	if strings.HasPrefix(filepath.Base(uri.Filename()), "_") {
 		for _, view := range s.views {
 			view.ignoredURIsMu.Lock()
 			view.ignoredURIs[uri] = struct{}{}
 			view.ignoredURIsMu.Unlock()
 		}
 		return
 	}

 	// Mark the file as open.
 	s.openFiles.Store(uri, true)

 	// Read the file on disk and compare it to the text provided.
 	// If it is the same as on disk, we can avoid sending it as an overlay to go/packages.
 	s.openOverlay(ctx, uri, text)

 	// Mark the file as just opened so that we know to re-run packages.Load on it.
 	// We do this because we may not be aware of all of the packages the file belongs to.
 	// A file may be in multiple views.
 	for _, view := range s.views {
 		if strings.HasPrefix(string(uri), string(view.Folder())) {
 			f, err := view.GetFile(ctx, uri)
 			if err != nil {
 				log.Error(ctx, "error getting file", nil, telemetry.File)
 				return
 			}
 			gof, ok := f.(*goFile)
 			if !ok {
 				log.Error(ctx, "not a Go file", nil, telemetry.File)
 				return
 			}
 			// Mark file as open.
 			gof.mu.Lock()
 			gof.justOpened = true
 			gof.mu.Unlock()
 		}
 	}
 }

 func (s *session) DidSave(uri span.URI) {
 	s.overlayMu.Lock()
 	defer s.overlayMu.Unlock()

 	if overlay, ok := s.overlays[uri]; ok {
 		overlay.sameContentOnDisk = true
 	}
 }

 func (s *session) DidClose(uri span.URI) {
 	s.openFiles.Delete(uri)
 }

 func (s *session) IsOpen(uri span.URI) bool {
 	_, open := s.openFiles.Load(uri)
 	return open
 }

 func (s *session) GetFile(uri span.URI) source.FileHandle {
 	if overlay := s.readOverlay(uri); overlay != nil {
 		return overlay
 	}
 	// Fall back to the cache-level file system.
 	return s.Cache().GetFile(uri)
 }

 func (s *session) SetOverlay(uri span.URI, data []byte) bool {
 	s.overlayMu.Lock()
 	defer func() {
 		s.overlayMu.Unlock()
 		s.filesWatchMap.Notify(uri)
 	}()

 	if data == nil {
 		delete(s.overlays, uri)
 		return false
 	}

 	o := s.overlays[uri]
 	firstChange := o != nil && o.unchanged

 	s.overlays[uri] = &overlay{
 		session:   s,
 		uri:       uri,
 		data:      data,
 		hash:      hashContents(data),
 		unchanged: o == nil,
 	}
 	return firstChange
 }

 // openOverlay adds the file content to the overlay.
 // It also checks if the provided content is equivalent to the file's content on disk.
 func (s *session) openOverlay(ctx context.Context, uri span.URI, data []byte) {
 	s.overlayMu.Lock()
 	defer func() {
 		s.overlayMu.Unlock()
 		s.filesWatchMap.Notify(uri)
 	}()
 	s.overlays[uri] = &overlay{
 		session:   s,
 		uri:       uri,
 		data:      data,
 		hash:      hashContents(data),
 		unchanged: true,
 	}
 	_, hash, err := s.cache.GetFile(uri).Read(ctx)
 	if err != nil {
 		log.Error(ctx, "failed to read", err, telemetry.File)
 		return
 	}
 	if hash == s.overlays[uri].hash {
 		s.overlays[uri].sameContentOnDisk = true
 	}
 }

 func (s *session) readOverlay(uri span.URI) *overlay {
 	s.overlayMu.Lock()
 	defer s.overlayMu.Unlock()

 	// We might have the content saved in an overlay.
 	if overlay, ok := s.overlays[uri]; ok {
 		return overlay
 	}
 	return nil
 }

 func (s *session) buildOverlay() map[string][]byte {
 	s.overlayMu.Lock()
 	defer s.overlayMu.Unlock()

 	overlays := make(map[string][]byte)
 	for uri, overlay := range s.overlays {
 		if overlay.sameContentOnDisk {
 			continue
 		}
 		overlays[uri.Filename()] = overlay.data
 	}
 	return overlays
 }

 func (s *session) DidChangeOutOfBand(ctx context.Context, f source.GoFile, changeType protocol.FileChangeType) {
 	if changeType == protocol.Deleted {
 		// After a deletion we must invalidate the package's metadata to
 		// force a go/packages invocation to refresh the package's file
 		// list.
 		f.(*goFile).invalidateMeta(ctx)
 	}

 	s.filesWatchMap.Notify(f.URI())
 }

 func (o *overlay) FileSystem() source.FileSystem {
 	return o.session
 }

 func (o *overlay) Identity() source.FileIdentity {
 	return source.FileIdentity{
 		URI:     o.uri,
 		Version: o.hash,
 	}
 }

 func (o *overlay) Kind() source.FileKind {
 	// TODO: Determine the file kind using textDocument.languageId.
 	return source.Go
 }

 func (o *overlay) Read(ctx context.Context) ([]byte, string, error) {
 	return o.data, o.hash, nil
 }

 type debugSession struct{ *session }

 func (s debugSession) ID() string         { return s.id }
 func (s debugSession) Cache() debug.Cache { return debugCache{s.cache} }
 func (s debugSession) Files() []*debug.File {
 	var files []*debug.File
 	seen := make(map[span.URI]*debug.File)
 	s.openFiles.Range(func(key interface{}, value interface{}) bool {
 		uri, ok := key.(span.URI)
 		if ok {
 			f := &debug.File{Session: s, URI: uri}
 			seen[uri] = f
 			files = append(files, f)
 		}
 		return true
 	})
 	s.overlayMu.Lock()
 	defer s.overlayMu.Unlock()
 	for _, overlay := range s.overlays {
 		f, ok := seen[overlay.uri]
 		if !ok {
 			f = &debug.File{Session: s, URI: overlay.uri}
 			seen[overlay.uri] = f
 			files = append(files, f)
 		}
 		f.Data = string(overlay.data)
 		f.Error = nil
 		f.Hash = overlay.hash
 	}
 	sort.Slice(files, func(i int, j int) bool {
 		return files[i].URI < files[j].URI
 	})
 	return files
 }

 func (s debugSession) File(hash string) *debug.File {
 	s.overlayMu.Lock()
 	defer s.overlayMu.Unlock()
 	for _, overlay := range s.overlays {
 		if overlay.hash == hash {
 			return &debug.File{
 				Session: s,
 				URI:     overlay.uri,
 				Data:    string(overlay.data),
 				Error:   nil,
 				Hash:    overlay.hash,
 			}
 		}
 	}
 	return &debug.File{
 		Session: s,
 		Hash:    hash,
 	}
 }
	// 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 cache

	import (
	"context"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"

	"golang.org/x/tools/internal/lsp/debug"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/lsp/telemetry"
	"golang.org/x/tools/internal/span"
	"golang.org/x/tools/internal/telemetry/log"
	"golang.org/x/tools/internal/telemetry/trace"
	"golang.org/x/tools/internal/xcontext"
	errors "golang.org/x/xerrors"
	)

	type session struct {
	cache *cache
	id string

	options source.Options

	viewMu sync.Mutex
	views []*view
	viewMap map[span.URI]source.View

	overlayMu sync.Mutex
	overlays map[span.URI]*overlay

	openFiles sync.Map
	filesWatchMap *WatchMap
	}

	type overlay struct {
	session *session
	uri span.URI
	data []byte
	hash string
	kind source.FileKind

	// sameContentOnDisk is true if a file has been saved on disk,
	// and therefore does not need to be part of the overlay sent to go/packages.
	sameContentOnDisk bool

	// unchanged is true if a file has not yet been edited.
	unchanged bool
	}

	func (s *session) Options() source.Options {
	return s.options
	}

	func (s *session) SetOptions(options source.Options) {
	s.options = options
	}

	func (s *session) Shutdown(ctx context.Context) {
	s.viewMu.Lock()
	defer s.viewMu.Unlock()
	for _, view := range s.views {
	view.shutdown(ctx)
	}
	s.views = nil
	s.viewMap = nil
	debug.DropSession(debugSession{s})
	}

	func (s *session) Cache() source.Cache {
	return s.cache
	}

	func (s *session) NewView(ctx context.Context, name string, folder span.URI, options source.Options) source.View {
	index := atomic.AddInt64(&viewIndex, 1)
	s.viewMu.Lock()
	defer s.viewMu.Unlock()
	// We want a true background context and not a detached context here
	// the spans need to be unrelated and no tag values should pollute it.
	baseCtx := trace.Detach(xcontext.Detach(ctx))
	backgroundCtx, cancel := context.WithCancel(baseCtx)
	v := &view{
	session: s,
	id: strconv.FormatInt(index, 10),
	options: options,
	baseCtx: baseCtx,
	backgroundCtx: backgroundCtx,
	cancel: cancel,
	name: name,
	folder: folder,
	filesByURI: make(map[span.URI]viewFile),
	filesByBase: make(map[string][]viewFile),
	mcache: &metadataCache{
	packages: make(map[packageID]*metadata),
	},
	ignoredURIs: make(map[span.URI]struct{}),
	}
	// Preemptively build the builtin package,
	// so we immediately add builtin.go to the list of ignored files.
	v.buildBuiltinPkg(ctx)

	s.views = append(s.views, v)
	// we always need to drop the view map
	s.viewMap = make(map[span.URI]source.View)
	debug.AddView(debugView{v})
	return v
	}

	// View returns the view by name.
	func (s *session) View(name string) source.View {
	s.viewMu.Lock()
	defer s.viewMu.Unlock()
	for _, view := range s.views {
	if view.Name() == name {
	return view
	}
	}
	return nil
	}

	// ViewOf returns a view corresponding to the given URI.
	// If the file is not already associated with a view, pick one using some heuristics.
	func (s *session) ViewOf(uri span.URI) source.View {
	s.viewMu.Lock()
	defer s.viewMu.Unlock()

	// Check if we already know this file.
	if v, found := s.viewMap[uri]; found {
	return v
	}
	// Pick the best view for this file and memoize the result.
	v := s.bestView(uri)
	s.viewMap[uri] = v
	return v
	}

	func (s *session) Views() []source.View {
	s.viewMu.Lock()
	defer s.viewMu.Unlock()
	result := make([]source.View, len(s.views))
	for i, v := range s.views {
	result[i] = v
	}
	return result
	}

	// bestView finds the best view to associate a given URI with.
	// viewMu must be held when calling this method.
	func (s *session) bestView(uri span.URI) source.View {
	// we need to find the best view for this file
	var longest source.View
	for _, view := range s.views {
	if longest != nil && len(longest.Folder()) > len(view.Folder()) {
	continue
	}
	if strings.HasPrefix(string(uri), string(view.Folder())) {
	longest = view
	}
	}
	if longest != nil {
	return longest
	}
	// TODO: are there any more heuristics we can use?
	return s.views[0]
	}

	func (s session) removeView(ctx context.Context, view view) error {
	s.viewMu.Lock()
	defer s.viewMu.Unlock()
	// we always need to drop the view map
	s.viewMap = make(map[span.URI]source.View)
	for i, v := range s.views {
	if view == v {
	// delete this view... we don't care about order but we do want to make
	// sure we can garbage collect the view
	s.views[i] = s.views[len(s.views)-1]
	s.views[len(s.views)-1] = nil
	s.views = s.views[:len(s.views)-1]
	v.shutdown(ctx)
	return nil
	}
	}
	return errors.Errorf("view %s for %v not found", view.Name(), view.Folder())
	}

	// TODO: Propagate the language ID through to the view.
	func (s *session) DidOpen(ctx context.Context, uri span.URI, _ source.FileKind, text []byte) {
	ctx = telemetry.File.With(ctx, uri)

	// Files with _ prefixes are ignored.
	if strings.HasPrefix(filepath.Base(uri.Filename()), "_") {
	for _, view := range s.views {
	view.ignoredURIsMu.Lock()
	view.ignoredURIs[uri] = struct{}{}
	view.ignoredURIsMu.Unlock()
	}
	return
	}

	// Mark the file as open.
	s.openFiles.Store(uri, true)

	// Read the file on disk and compare it to the text provided.
	// If it is the same as on disk, we can avoid sending it as an overlay to go/packages.
	s.openOverlay(ctx, uri, text)

	// Mark the file as just opened so that we know to re-run packages.Load on it.
	// We do this because we may not be aware of all of the packages the file belongs to.
	// A file may be in multiple views.
	for _, view := range s.views {
	if strings.HasPrefix(string(uri), string(view.Folder())) {
	f, err := view.GetFile(ctx, uri)
	if err != nil {
	log.Error(ctx, "error getting file", nil, telemetry.File)
	return
	}
	gof, ok := f.(*goFile)
	if !ok {
	log.Error(ctx, "not a Go file", nil, telemetry.File)
	return
	}
	// Mark file as open.
	gof.mu.Lock()
	gof.justOpened = true
	gof.mu.Unlock()
	}
	}
	}

	func (s *session) DidSave(uri span.URI) {
	s.overlayMu.Lock()
	defer s.overlayMu.Unlock()

	if overlay, ok := s.overlays[uri]; ok {
	overlay.sameContentOnDisk = true
	}
	}

	func (s *session) DidClose(uri span.URI) {
	s.openFiles.Delete(uri)
	}

	func (s *session) IsOpen(uri span.URI) bool {
	_, open := s.openFiles.Load(uri)
	return open
	}

	func (s *session) GetFile(uri span.URI) source.FileHandle {
	if overlay := s.readOverlay(uri); overlay != nil {
	return overlay
	}
	// Fall back to the cache-level file system.
	return s.Cache().GetFile(uri)
	}

	func (s *session) SetOverlay(uri span.URI, data []byte) bool {
	s.overlayMu.Lock()
	defer func() {
	s.overlayMu.Unlock()
	s.filesWatchMap.Notify(uri)
	}()

	if data == nil {
	delete(s.overlays, uri)
	return false
	}

	o := s.overlays[uri]
	firstChange := o != nil && o.unchanged

	s.overlays[uri] = &overlay{
	session: s,
	uri: uri,
	data: data,
	hash: hashContents(data),
	unchanged: o == nil,
	}
	return firstChange
	}

	// openOverlay adds the file content to the overlay.
	// It also checks if the provided content is equivalent to the file's content on disk.
	func (s *session) openOverlay(ctx context.Context, uri span.URI, data []byte) {
	s.overlayMu.Lock()
	defer func() {
	s.overlayMu.Unlock()
	s.filesWatchMap.Notify(uri)
	}()
	s.overlays[uri] = &overlay{
	session: s,
	uri: uri,
	data: data,
	hash: hashContents(data),
	unchanged: true,
	}
	_, hash, err := s.cache.GetFile(uri).Read(ctx)
	if err != nil {
	log.Error(ctx, "failed to read", err, telemetry.File)
	return
	}
	if hash == s.overlays[uri].hash {
	s.overlays[uri].sameContentOnDisk = true
	}
	}

	func (s session) readOverlay(uri span.URI) overlay {
	s.overlayMu.Lock()
	defer s.overlayMu.Unlock()

	// We might have the content saved in an overlay.
	if overlay, ok := s.overlays[uri]; ok {
	return overlay
	}
	return nil
	}

	func (s *session) buildOverlay() map[string][]byte {
	s.overlayMu.Lock()
	defer s.overlayMu.Unlock()

	overlays := make(map[string][]byte)
	for uri, overlay := range s.overlays {
	if overlay.sameContentOnDisk {
	continue
	}
	overlays[uri.Filename()] = overlay.data
	}
	return overlays
	}

	func (s *session) DidChangeOutOfBand(ctx context.Context, f source.GoFile, changeType protocol.FileChangeType) {
	if changeType == protocol.Deleted {
	// After a deletion we must invalidate the package's metadata to
	// force a go/packages invocation to refresh the package's file
	// list.
	f.(*goFile).invalidateMeta(ctx)
	}

	s.filesWatchMap.Notify(f.URI())
	}

	func (o *overlay) FileSystem() source.FileSystem {
	return o.session
	}

	func (o *overlay) Identity() source.FileIdentity {
	return source.FileIdentity{
	URI: o.uri,
	Version: o.hash,
	}
	}

	func (o *overlay) Kind() source.FileKind {
	// TODO: Determine the file kind using textDocument.languageId.
	return source.Go
	}

	func (o *overlay) Read(ctx context.Context) ([]byte, string, error) {
	return o.data, o.hash, nil
	}

	type debugSession struct{ *session }

	func (s debugSession) ID() string { return s.id }
	func (s debugSession) Cache() debug.Cache { return debugCache{s.cache} }
	func (s debugSession) Files() []*debug.File {
	var files []*debug.File
	seen := make(map[span.URI]*debug.File)
	s.openFiles.Range(func(key interface{}, value interface{}) bool {
	uri, ok := key.(span.URI)
	if ok {
	f := &debug.File{Session: s, URI: uri}
	seen[uri] = f
	files = append(files, f)
	}
	return true
	})
	s.overlayMu.Lock()
	defer s.overlayMu.Unlock()
	for _, overlay := range s.overlays {
	f, ok := seen[overlay.uri]
	if !ok {
	f = &debug.File{Session: s, URI: overlay.uri}
	seen[overlay.uri] = f
	files = append(files, f)
	}
	f.Data = string(overlay.data)
	f.Error = nil
	f.Hash = overlay.hash
	}
	sort.Slice(files, func(i int, j int) bool {
	return files[i].URI < files[j].URI
	})
	return files
	}

	func (s debugSession) File(hash string) *debug.File {
	s.overlayMu.Lock()
	defer s.overlayMu.Unlock()
	for _, overlay := range s.overlays {
	if overlay.hash == hash {
	return &debug.File{
	Session: s,
	URI: overlay.uri,
	Data: string(overlay.data),
	Error: nil,
	Hash: overlay.hash,
	}
	}
	}
	return &debug.File{
	Session: s,
	Hash: hash,
	}
	}