blob: 85dd2e3855f660ee1b5c6753495fc5145efe29ab [file] [log] [blame]
// 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"
"fmt"
"strconv"
"strings"
"sync"
"sync/atomic"
"golang.org/x/tools/gopls/internal/govulncheck"
"golang.org/x/tools/gopls/internal/lsp/source"
"golang.org/x/tools/gopls/internal/span"
"golang.org/x/tools/internal/bug"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/gocommand"
"golang.org/x/tools/internal/imports"
"golang.org/x/tools/internal/persistent"
"golang.org/x/tools/internal/xcontext"
)
type Session struct {
// Unique identifier for this session.
id string
// Immutable attributes shared across views.
cache *Cache // shared cache
gocmdRunner *gocommand.Runner // limits go command concurrency
optionsMu sync.Mutex
options *source.Options
viewMu sync.Mutex
views []*View
viewMap map[span.URI]*View // map of URI->best view
*overlayFS
}
// ID returns the unique identifier for this session on this server.
func (s *Session) ID() string { return s.id }
func (s *Session) String() string { return s.id }
// Options returns a copy of the SessionOptions for this session.
func (s *Session) Options() *source.Options {
s.optionsMu.Lock()
defer s.optionsMu.Unlock()
return s.options
}
// SetOptions sets the options of this session to new values.
func (s *Session) SetOptions(options *source.Options) {
s.optionsMu.Lock()
defer s.optionsMu.Unlock()
s.options = options
}
// Shutdown the session and all views it has created.
func (s *Session) Shutdown(ctx context.Context) {
var views []*View
s.viewMu.Lock()
views = append(views, s.views...)
s.views = nil
s.viewMap = nil
s.viewMu.Unlock()
for _, view := range views {
view.shutdown()
}
event.Log(ctx, "Shutdown session", KeyShutdownSession.Of(s))
}
// Cache returns the cache that created this session, for debugging only.
func (s *Session) Cache() *Cache {
return s.cache
}
// NewView creates a new View, returning it and its first snapshot. If a
// non-empty tempWorkspace directory is provided, the View will record a copy
// of its gopls workspace module in that directory, so that client tooling
// can execute in the same main module. On success it also returns a release
// function that must be called when the Snapshot is no longer needed.
func (s *Session) NewView(ctx context.Context, name string, folder span.URI, options *source.Options) (*View, source.Snapshot, func(), error) {
s.viewMu.Lock()
defer s.viewMu.Unlock()
for _, view := range s.views {
if span.SameExistingFile(view.folder, folder) {
return nil, nil, nil, source.ErrViewExists
}
}
view, snapshot, release, err := s.createView(ctx, name, folder, options, 0)
if err != nil {
return nil, nil, nil, err
}
s.views = append(s.views, view)
// we always need to drop the view map
s.viewMap = make(map[span.URI]*View)
return view, snapshot, release, nil
}
// TODO(rfindley): clarify that createView can never be cancelled (with the
// possible exception of server shutdown).
func (s *Session) createView(ctx context.Context, name string, folder span.URI, options *source.Options, seqID uint64) (*View, *snapshot, func(), error) {
index := atomic.AddInt64(&viewIndex, 1)
// Get immutable workspace information.
info, err := s.getWorkspaceInformation(ctx, folder, options)
if err != nil {
return nil, nil, func() {}, err
}
wsModFiles, wsModFilesErr := computeWorkspaceModFiles(ctx, info.gomod, info.effectiveGOWORK(), info.effectiveGO111MODULE(), s)
// 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 := event.Detach(xcontext.Detach(ctx))
backgroundCtx, cancel := context.WithCancel(baseCtx)
v := &View{
id: strconv.FormatInt(index, 10),
gocmdRunner: s.gocmdRunner,
initialWorkspaceLoad: make(chan struct{}),
initializationSema: make(chan struct{}, 1),
options: options,
baseCtx: baseCtx,
name: name,
folder: folder,
moduleUpgrades: map[span.URI]map[string]string{},
vulns: map[span.URI]*govulncheck.Result{},
fs: s.overlayFS,
workspaceInformation: info,
}
v.importsState = &importsState{
ctx: backgroundCtx,
processEnv: &imports.ProcessEnv{
GocmdRunner: s.gocmdRunner,
SkipPathInScan: func(dir string) bool {
prefix := strings.TrimSuffix(string(v.folder), "/") + "/"
uri := strings.TrimSuffix(string(span.URIFromPath(dir)), "/")
if !strings.HasPrefix(uri+"/", prefix) {
return false
}
filterer := source.NewFilterer(options.DirectoryFilters)
rel := strings.TrimPrefix(uri, prefix)
disallow := filterer.Disallow(rel)
return disallow
},
},
}
v.snapshot = &snapshot{
sequenceID: seqID,
globalID: nextSnapshotID(),
view: v,
backgroundCtx: backgroundCtx,
cancel: cancel,
store: s.cache.store,
packages: persistent.NewMap(packageIDLessInterface),
meta: new(metadataGraph),
files: newFilesMap(),
parseCache: new(parseCache),
activePackages: persistent.NewMap(packageIDLessInterface),
symbolizeHandles: persistent.NewMap(uriLessInterface),
analyses: persistent.NewMap(analysisKeyLessInterface),
workspacePackages: make(map[PackageID]PackagePath),
unloadableFiles: make(map[span.URI]struct{}),
parseModHandles: persistent.NewMap(uriLessInterface),
parseWorkHandles: persistent.NewMap(uriLessInterface),
modTidyHandles: persistent.NewMap(uriLessInterface),
modVulnHandles: persistent.NewMap(uriLessInterface),
modWhyHandles: persistent.NewMap(uriLessInterface),
knownSubdirs: newKnownDirsSet(),
workspaceModFiles: wsModFiles,
workspaceModFilesErr: wsModFilesErr,
}
// Save one reference in the view.
v.releaseSnapshot = v.snapshot.Acquire()
// Record the environment of the newly created view in the log.
event.Log(ctx, viewEnv(v))
// Initialize the view without blocking.
initCtx, initCancel := context.WithCancel(xcontext.Detach(ctx))
v.initCancelFirstAttempt = initCancel
snapshot := v.snapshot
// Pass a second reference to the background goroutine.
bgRelease := snapshot.Acquire()
go func() {
defer bgRelease()
snapshot.initialize(initCtx, true)
}()
// Return a third reference to the caller.
return v, snapshot, snapshot.Acquire(), nil
}
// View returns a view with a matching name, if the session has one.
func (s *Session) View(name string) *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) (*View, error) {
s.viewMu.Lock()
defer s.viewMu.Unlock()
return s.viewOfLocked(uri)
}
// Precondition: caller holds s.viewMu lock.
func (s *Session) viewOfLocked(uri span.URI) (*View, error) {
// Check if we already know this file.
if v, found := s.viewMap[uri]; found {
return v, nil
}
// Pick the best view for this file and memoize the result.
if len(s.views) == 0 {
return nil, fmt.Errorf("no views in session")
}
s.viewMap[uri] = bestViewForURI(uri, s.views)
return s.viewMap[uri], nil
}
func (s *Session) Views() []*View {
s.viewMu.Lock()
defer s.viewMu.Unlock()
result := make([]*View, len(s.views))
copy(result, s.views)
return result
}
// bestViewForURI returns the most closely matching view for the given URI
// out of the given set of views.
func bestViewForURI(uri span.URI, views []*View) *View {
// we need to find the best view for this file
var longest *View
for _, view := range views {
if longest != nil && len(longest.Folder()) > len(view.Folder()) {
continue
}
// TODO(rfindley): this should consider the workspace layout (i.e.
// go.work).
if view.contains(uri) {
longest = view
}
}
if longest != nil {
return longest
}
// Try our best to return a view that knows the file.
for _, view := range views {
if view.knownFile(uri) {
return view
}
}
// TODO: are there any more heuristics we can use?
return views[0]
}
// RemoveView removes the view v from the session
func (s *Session) RemoveView(view *View) {
s.viewMu.Lock()
defer s.viewMu.Unlock()
i := s.dropView(view)
if i == -1 { // error reported elsewhere
return
}
// delete this view... we don't care about order but we do want to make
// sure we can garbage collect the view
s.views = removeElement(s.views, i)
}
// updateView recreates the view with the given options.
//
// If the resulting error is non-nil, the view may or may not have already been
// dropped from the session.
func (s *Session) updateView(ctx context.Context, view *View, options *source.Options) (*View, error) {
s.viewMu.Lock()
defer s.viewMu.Unlock()
return s.updateViewLocked(ctx, view, options)
}
func (s *Session) updateViewLocked(ctx context.Context, view *View, options *source.Options) (*View, error) {
// Preserve the snapshot ID if we are recreating the view.
view.snapshotMu.Lock()
if view.snapshot == nil {
view.snapshotMu.Unlock()
panic("updateView called after View was already shut down")
}
seqID := view.snapshot.sequenceID // Preserve sequence IDs when updating a view in place.
view.snapshotMu.Unlock()
i := s.dropView(view)
if i == -1 {
return nil, fmt.Errorf("view %q not found", view.id)
}
v, _, release, err := s.createView(ctx, view.name, view.folder, options, seqID)
release()
if err != nil {
// we have dropped the old view, but could not create the new one
// this should not happen and is very bad, but we still need to clean
// up the view array if it happens
s.views = removeElement(s.views, i)
return nil, err
}
// substitute the new view into the array where the old view was
s.views[i] = v
return v, nil
}
// removeElement removes the ith element from the slice replacing it with the last element.
// TODO(adonovan): generics, someday.
func removeElement(slice []*View, index int) []*View {
last := len(slice) - 1
slice[index] = slice[last]
slice[last] = nil // aid GC
return slice[:last]
}
// dropView removes v from the set of views for the receiver s and calls
// v.shutdown, returning the index of v in s.views (if found), or -1 if v was
// not found. s.viewMu must be held while calling this function.
func (s *Session) dropView(v *View) int {
// we always need to drop the view map
s.viewMap = make(map[span.URI]*View)
for i := range s.views {
if v == s.views[i] {
// we found the view, drop it and return the index it was found at
s.views[i] = nil
v.shutdown()
return i
}
}
// TODO(rfindley): it looks wrong that we don't shutdown v in this codepath.
// We should never get here.
bug.Reportf("tried to drop nonexistent view %q", v.id)
return -1
}
func (s *Session) ModifyFiles(ctx context.Context, changes []source.FileModification) error {
_, release, err := s.DidModifyFiles(ctx, changes)
release()
return err
}
// TODO(rfindley): fileChange seems redundant with source.FileModification.
// De-dupe into a common representation for changes.
type fileChange struct {
content []byte
exists bool
fileHandle source.FileHandle
// isUnchanged indicates whether the file action is one that does not
// change the actual contents of the file. Opens and closes should not
// be treated like other changes, since the file content doesn't change.
isUnchanged bool
}
// DidModifyFiles reports a file modification to the session. It returns
// the new snapshots after the modifications have been applied, paired with
// the affected file URIs for those snapshots.
// On success, it returns a release function that
// must be called when the snapshots are no longer needed.
//
// TODO(rfindley): what happens if this function fails? It must leave us in a
// broken state, which we should surface to the user, probably as a request to
// restart gopls.
func (s *Session) DidModifyFiles(ctx context.Context, changes []source.FileModification) (map[source.Snapshot][]span.URI, func(), error) {
s.viewMu.Lock()
defer s.viewMu.Unlock()
// Update overlays.
//
// TODO(rfindley): I think we do this while holding viewMu to prevent views
// from seeing the updated file content before they have processed
// invalidations, which could lead to a partial view of the changes (i.e.
// spurious diagnostics). However, any such view would immediately be
// invalidated here, so it is possible that we could update overlays before
// acquiring viewMu.
if err := s.updateOverlays(ctx, changes); err != nil {
return nil, nil, err
}
// Re-create views whose definition may have changed.
//
// checkViews controls whether to re-evaluate view definitions when
// collecting views below. Any addition or deletion of a go.mod or go.work
// file may have affected the definition of the view.
checkViews := false
for _, c := range changes {
if isGoMod(c.URI) || isGoWork(c.URI) {
// Change, InvalidateMetadata, and UnknownFileAction actions do not cause
// us to re-evaluate views.
redoViews := (c.Action != source.Change &&
c.Action != source.InvalidateMetadata &&
c.Action != source.UnknownFileAction)
if redoViews {
checkViews = true
break
}
}
}
if checkViews {
for _, view := range s.views {
// TODO(rfindley): can we avoid running the go command (go env)
// synchronously to change processing? Can we assume that the env did not
// change, and derive go.work using a combination of the configured
// GOWORK value and filesystem?
info, err := s.getWorkspaceInformation(ctx, view.folder, view.Options())
if err != nil {
// Catastrophic failure, equivalent to a failure of session
// initialization and therefore should almost never happen. One
// scenario where this failure mode could occur is if some file
// permissions have changed preventing us from reading go.mod
// files.
//
// TODO(rfindley): consider surfacing this error more loudly. We
// could report a bug, but it's not really a bug.
event.Error(ctx, "fetching workspace information", err)
}
if info != view.workspaceInformation {
_, err := s.updateViewLocked(ctx, view, view.Options())
if err != nil {
// More catastrophic failure. The view may or may not still exist.
// The best we can do is log and move on.
event.Error(ctx, "recreating view", err)
}
}
}
}
// Collect information about views affected by these changes.
views := make(map[*View]map[span.URI]*fileChange)
affectedViews := map[span.URI][]*View{}
// forceReloadMetadata records whether any change is the magic
// source.InvalidateMetadata action.
forceReloadMetadata := false
for _, c := range changes {
if c.Action == source.InvalidateMetadata {
forceReloadMetadata = true
}
// Build the list of affected views.
var changedViews []*View
for _, view := range s.views {
// Don't propagate changes that are outside of the view's scope
// or knowledge.
if !view.relevantChange(c) {
continue
}
changedViews = append(changedViews, view)
}
// If the change is not relevant to any view, but the change is
// happening in the editor, assign it the most closely matching view.
if len(changedViews) == 0 {
if c.OnDisk {
continue
}
bestView, err := s.viewOfLocked(c.URI)
if err != nil {
return nil, nil, err
}
changedViews = append(changedViews, bestView)
}
affectedViews[c.URI] = changedViews
isUnchanged := c.Action == source.Open || c.Action == source.Close
// Apply the changes to all affected views.
for _, view := range changedViews {
// Make sure that the file is added to the view's seenFiles set.
view.markKnown(c.URI)
if _, ok := views[view]; !ok {
views[view] = make(map[span.URI]*fileChange)
}
fh, err := s.ReadFile(ctx, c.URI)
if err != nil {
return nil, nil, err
}
content, err := fh.Content()
if err != nil {
// Ignore the error: the file may be deleted.
content = nil
}
views[view][c.URI] = &fileChange{
content: content,
exists: err == nil,
fileHandle: fh,
isUnchanged: isUnchanged,
}
}
}
var releases []func()
viewToSnapshot := map[*View]*snapshot{}
for view, changed := range views {
snapshot, release := view.invalidateContent(ctx, changed, forceReloadMetadata)
releases = append(releases, release)
viewToSnapshot[view] = snapshot
}
// The release function is called when the
// returned URIs no longer need to be valid.
release := func() {
for _, release := range releases {
release()
}
}
// We only want to diagnose each changed file once, in the view to which
// it "most" belongs. We do this by picking the best view for each URI,
// and then aggregating the set of snapshots and their URIs (to avoid
// diagnosing the same snapshot multiple times).
snapshotURIs := map[source.Snapshot][]span.URI{}
for _, mod := range changes {
viewSlice, ok := affectedViews[mod.URI]
if !ok || len(viewSlice) == 0 {
continue
}
view := bestViewForURI(mod.URI, viewSlice)
snapshot, ok := viewToSnapshot[view]
if !ok {
panic(fmt.Sprintf("no snapshot for view %s", view.Folder()))
}
snapshotURIs[snapshot] = append(snapshotURIs[snapshot], mod.URI)
}
return snapshotURIs, release, nil
}
// ExpandModificationsToDirectories returns the set of changes with the
// directory changes removed and expanded to include all of the files in
// the directory.
func (s *Session) ExpandModificationsToDirectories(ctx context.Context, changes []source.FileModification) []source.FileModification {
var snapshots []*snapshot
s.viewMu.Lock()
for _, v := range s.views {
snapshot, release, err := v.getSnapshot()
if err != nil {
continue // view is shut down; continue with others
}
defer release()
snapshots = append(snapshots, snapshot)
}
s.viewMu.Unlock()
knownDirs := knownDirectories(ctx, snapshots)
defer knownDirs.Destroy()
var result []source.FileModification
for _, c := range changes {
if !knownDirs.Contains(c.URI) {
result = append(result, c)
continue
}
affectedFiles := knownFilesInDir(ctx, snapshots, c.URI)
var fileChanges []source.FileModification
for uri := range affectedFiles {
fileChanges = append(fileChanges, source.FileModification{
URI: uri,
Action: c.Action,
LanguageID: "",
OnDisk: c.OnDisk,
// changes to directories cannot include text or versions
})
}
result = append(result, fileChanges...)
}
return result
}
// knownDirectories returns all of the directories known to the given
// snapshots, including workspace directories and their subdirectories.
// It is responsibility of the caller to destroy the returned set.
func knownDirectories(ctx context.Context, snapshots []*snapshot) knownDirsSet {
result := newKnownDirsSet()
for _, snapshot := range snapshots {
dirs := snapshot.dirs(ctx)
for _, dir := range dirs {
result.Insert(dir)
}
knownSubdirs := snapshot.getKnownSubdirs(dirs)
result.SetAll(knownSubdirs)
knownSubdirs.Destroy()
}
return result
}
// knownFilesInDir returns the files known to the snapshots in the session.
// It does not respect symlinks.
func knownFilesInDir(ctx context.Context, snapshots []*snapshot, dir span.URI) map[span.URI]struct{} {
files := map[span.URI]struct{}{}
for _, snapshot := range snapshots {
for _, uri := range snapshot.knownFilesInDir(ctx, dir) {
files[uri] = struct{}{}
}
}
return files
}
// Precondition: caller holds s.viewMu lock.
// TODO(rfindley): move this to fs_overlay.go.
func (fs *overlayFS) updateOverlays(ctx context.Context, changes []source.FileModification) error {
fs.mu.Lock()
defer fs.mu.Unlock()
for _, c := range changes {
// Don't update overlays for metadata invalidations.
if c.Action == source.InvalidateMetadata {
continue
}
o, ok := fs.overlays[c.URI]
// If the file is not opened in an overlay and the change is on disk,
// there's no need to update an overlay. If there is an overlay, we
// may need to update the overlay's saved value.
if !ok && c.OnDisk {
continue
}
// Determine the file kind on open, otherwise, assume it has been cached.
var kind source.FileKind
switch c.Action {
case source.Open:
kind = source.FileKindForLang(c.LanguageID)
default:
if !ok {
return fmt.Errorf("updateOverlays: modifying unopened overlay %v", c.URI)
}
kind = o.kind
}
// Closing a file just deletes its overlay.
if c.Action == source.Close {
delete(fs.overlays, c.URI)
continue
}
// If the file is on disk, check if its content is the same as in the
// overlay. Saves and on-disk file changes don't come with the file's
// content.
text := c.Text
if text == nil && (c.Action == source.Save || c.OnDisk) {
if !ok {
return fmt.Errorf("no known content for overlay for %s", c.Action)
}
text = o.content
}
// On-disk changes don't come with versions.
version := c.Version
if c.OnDisk || c.Action == source.Save {
version = o.version
}
hash := source.HashOf(text)
var sameContentOnDisk bool
switch c.Action {
case source.Delete:
// Do nothing. sameContentOnDisk should be false.
case source.Save:
// Make sure the version and content (if present) is the same.
if false && o.version != version { // Client no longer sends the version
return fmt.Errorf("updateOverlays: saving %s at version %v, currently at %v", c.URI, c.Version, o.version)
}
if c.Text != nil && o.hash != hash {
return fmt.Errorf("updateOverlays: overlay %s changed on save", c.URI)
}
sameContentOnDisk = true
default:
fh, err := fs.delegate.ReadFile(ctx, c.URI)
if err != nil {
return err
}
_, readErr := fh.Content()
sameContentOnDisk = (readErr == nil && fh.FileIdentity().Hash == hash)
}
o = &Overlay{
uri: c.URI,
version: version,
content: text,
kind: kind,
hash: hash,
saved: sameContentOnDisk,
}
// NOTE: previous versions of this code checked here that the overlay had a
// view and file kind (but we don't know why).
fs.overlays[c.URI] = o
}
return nil
}
// FileWatchingGlobPatterns returns glob patterns to watch every directory
// known by the view. For views within a module, this is the module root,
// any directory in the module root, and any replace targets.
func (s *Session) FileWatchingGlobPatterns(ctx context.Context) map[string]struct{} {
s.viewMu.Lock()
defer s.viewMu.Unlock()
patterns := map[string]struct{}{}
for _, view := range s.views {
snapshot, release, err := view.getSnapshot()
if err != nil {
continue // view is shut down; continue with others
}
for k, v := range snapshot.fileWatchingGlobPatterns(ctx) {
patterns[k] = v
}
release()
}
return patterns
}