internal/lsp/cache/view.go - tools - Git at Google

 // Copyright 2018 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"
 	"go/ast"
 	"go/token"
 	"go/types"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
 	"sync"

 	"golang.org/x/tools/go/packages"
 	"golang.org/x/tools/internal/imports"
 	"golang.org/x/tools/internal/lsp/debug"
 	"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"
 )

 type view struct {
 	session *session
 	id      string

 	options source.Options

 	// mu protects all mutable state of the view.
 	mu sync.Mutex

 	// baseCtx is the context handed to NewView. This is the parent of all
 	// background contexts created for this view.
 	baseCtx context.Context

 	// backgroundCtx is the current context used by background tasks initiated
 	// by the view.
 	backgroundCtx context.Context

 	// cancel is called when all action being performed by the current view
 	// should be stopped.
 	cancel context.CancelFunc

 	// Name is the user visible name of this view.
 	name string

 	// Folder is the root of this view.
 	folder span.URI

 	// process is the process env for this view.
 	// Note: this contains cached module and filesystem state.
 	//
 	// TODO(suzmue): the state cached in the process env is specific to each view,
 	// however, there is state that can be shared between views that is not currently
 	// cached, like the module cache.
 	processEnv *imports.ProcessEnv

 	// modFileVersions stores the last seen versions of the module files that are used
 	// by processEnvs resolver.
 	// TODO(suzmue): These versions may not actually be on disk.
 	modFileVersions map[string]string

 	// keep track of files by uri and by basename, a single file may be mapped
 	// to multiple uris, and the same basename may map to multiple files
 	filesByURI  map[span.URI]viewFile
 	filesByBase map[string][]viewFile

 	// mcache caches metadata for the packages of the opened files in a view.
 	mcache *metadataCache

 	// builtin is used to resolve builtin types.
 	builtin *builtinPkg

 	// ignoredURIs is the set of URIs of files that we ignore.
 	ignoredURIsMu sync.Mutex
 	ignoredURIs   map[span.URI]struct{}
 }

 type metadataCache struct {
 	mu       sync.Mutex // guards both maps
 	packages map[packageID]*metadata
 }

 type metadata struct {
 	id         packageID
 	pkgPath    packagePath
 	name       string
 	files      []span.URI
 	key        string
 	typesSizes types.Sizes
 	parents    map[packageID]bool
 	children   map[packageID]*metadata
 	errors     []packages.Error
 }

 func (v *view) Session() source.Session {
 	return v.session
 }

 // Name returns the user visible name of this view.
 func (v *view) Name() string {
 	return v.name
 }

 // Folder returns the root of this view.
 func (v *view) Folder() span.URI {
 	return v.folder
 }

 func (v *view) Options() source.Options {
 	return v.options
 }

 func (v *view) SetOptions(options source.Options) {
 	v.options = options
 }

 // Config returns the configuration used for the view's interaction with the
 // go/packages API. It is shared across all views.
 func (v *view) Config(ctx context.Context) *packages.Config {
 	// TODO: Should we cache the config and/or overlay somewhere?
 	return &packages.Config{
 		Dir:        v.folder.Filename(),
 		Env:        v.options.Env,
 		BuildFlags: v.options.BuildFlags,
 		Mode: packages.NeedName |
 			packages.NeedFiles |
 			packages.NeedCompiledGoFiles |
 			packages.NeedImports |
 			packages.NeedDeps |
 			packages.NeedTypesSizes,
 		Fset:    v.session.cache.fset,
 		Overlay: v.session.buildOverlay(),
 		ParseFile: func(*token.FileSet, string, []byte) (*ast.File, error) {
 			panic("go/packages must not be used to parse files")
 		},
 		Logf: func(format string, args ...interface{}) {
 			log.Print(ctx, fmt.Sprintf(format, args...))
 		},
 		Tests: true,
 	}
 }

 func (v *view) RunProcessEnvFunc(ctx context.Context, fn func(*imports.Options) error, opts *imports.Options) error {
 	v.mu.Lock()
 	defer v.mu.Unlock()
 	if v.processEnv == nil {
 		var err error
 		if v.processEnv, err = v.buildProcessEnv(ctx); err != nil {
 			return err
 		}
 	}

 	// Before running the user provided function, clear caches in the resolver.
 	if v.modFilesChanged() {
 		if r, ok := v.processEnv.GetResolver().(*imports.ModuleResolver); ok {
 			// Clear the resolver cache and set Initialized to false.
 			r.Initialized = false
 			r.Main = nil
 			r.ModsByModPath = nil
 			r.ModsByDir = nil
 			// Reset the modFileVersions.
 			v.modFileVersions = nil
 		}
 	}

 	// Run the user function.
 	opts.Env = v.processEnv
 	if err := fn(opts); err != nil {
 		return err
 	}

 	// If applicable, store the file versions of the 'go.mod' files that are
 	// looked at by the resolver.
 	v.storeModFileVersions()

 	return nil
 }

 func (v *view) buildProcessEnv(ctx context.Context) (*imports.ProcessEnv, error) {
 	cfg := v.Config(ctx)
 	env := &imports.ProcessEnv{
 		WorkingDir: cfg.Dir,
 		Logf: func(format string, args ...interface{}) {
 			log.Print(ctx, fmt.Sprintf(format, args...))
 		},
 	}
 	for _, kv := range cfg.Env {
 		split := strings.Split(kv, "=")
 		if len(split) < 2 {
 			continue
 		}
 		switch split[0] {
 		case "GOPATH":
 			env.GOPATH = split[1]
 		case "GOROOT":
 			env.GOROOT = split[1]
 		case "GO111MODULE":
 			env.GO111MODULE = split[1]
 		case "GOPROXY":
 			env.GOPROXY = split[1]
 		case "GOFLAGS":
 			env.GOFLAGS = split[1]
 		case "GOSUMDB":
 			env.GOSUMDB = split[1]
 		}
 	}

 	if env.GOPATH == "" {
 		cmd := exec.CommandContext(ctx, "go", "env", "GOPATH")
 		cmd.Env = cfg.Env
 		if out, err := cmd.CombinedOutput(); err != nil {
 			return nil, err
 		} else {
 			env.GOPATH = strings.TrimSpace(string(out))
 		}
 	}
 	return env, nil
 }

 func (v *view) modFilesChanged() bool {
 	// Check the versions of the 'go.mod' files of the main module
 	// and modules included by a replace directive. Return true if
 	// any of these file versions do not match.
 	for filename, version := range v.modFileVersions {
 		if version != v.fileVersion(filename) {
 			return true
 		}
 	}
 	return false
 }

 func (v *view) storeModFileVersions() {
 	// Store the mod files versions, if we are using a ModuleResolver.
 	r, moduleMode := v.processEnv.GetResolver().(*imports.ModuleResolver)
 	if !moduleMode || !r.Initialized {
 		return
 	}
 	v.modFileVersions = make(map[string]string)

 	// Get the file versions of the 'go.mod' files of the main module
 	// and modules included by a replace directive in the resolver.
 	for _, mod := range r.ModsByModPath {
 		if (mod.Main || mod.Replace != nil) && mod.GoMod != "" {
 			v.modFileVersions[mod.GoMod] = v.fileVersion(mod.GoMod)
 		}
 	}
 }

 func (v *view) fileVersion(filename string) string {
 	uri := span.FileURI(filename)
 	f := v.session.GetFile(uri)
 	return f.Identity().Version
 }

 func (v *view) Shutdown(ctx context.Context) {
 	v.session.removeView(ctx, v)
 }

 func (v *view) shutdown(context.Context) {
 	v.mu.Lock()
 	defer v.mu.Unlock()
 	if v.cancel != nil {
 		v.cancel()
 		v.cancel = nil
 	}
 	debug.DropView(debugView{v})
 }

 // Ignore checks if the given URI is a URI we ignore.
 // As of right now, we only ignore files in the "builtin" package.
 func (v *view) Ignore(uri span.URI) bool {
 	v.ignoredURIsMu.Lock()
 	defer v.ignoredURIsMu.Unlock()

 	_, ok := v.ignoredURIs[uri]
 	return ok
 }

 func (v *view) BackgroundContext() context.Context {
 	v.mu.Lock()
 	defer v.mu.Unlock()

 	return v.backgroundCtx
 }

 func (v *view) BuiltinPackage() source.BuiltinPackage {
 	return v.builtin
 }

 // SetContent sets the overlay contents for a file.
 func (v *view) SetContent(ctx context.Context, uri span.URI, content []byte) (bool, error) {
 	v.mu.Lock()
 	defer v.mu.Unlock()

 	// Cancel all still-running previous requests, since they would be
 	// operating on stale data.
 	v.cancel()
 	v.backgroundCtx, v.cancel = context.WithCancel(v.baseCtx)

 	if !v.Ignore(uri) {
 		return v.session.SetOverlay(uri, content), nil
 	}
 	return false, nil
 }

 // invalidateContent invalidates the content of a Go file,
 // including any position and type information that depends on it.
 func (f *goFile) invalidateContent(ctx context.Context) {
 	// Mutex acquisition order here is important. It must match the order
 	// in loadParseTypecheck to avoid deadlocks.
 	f.view.mcache.mu.Lock()
 	defer f.view.mcache.mu.Unlock()

 	var toDelete []packageID
 	f.mu.Lock()
 	for id, cph := range f.pkgs {
 		if cph != nil {
 			toDelete = append(toDelete, id)
 		}
 	}
 	f.mu.Unlock()

 	f.handleMu.Lock()
 	defer f.handleMu.Unlock()

 	// Remove the package and all of its reverse dependencies from the cache.
 	for _, id := range toDelete {
 		f.view.remove(ctx, id, map[packageID]struct{}{})
 	}

 	f.handle = nil
 }

 // invalidateMeta invalidates package metadata for all files in f's
 // package. This forces f's package's metadata to be reloaded next
 // time the package is checked.
 func (f *goFile) invalidateMeta(ctx context.Context) {
 	pkgs, err := f.GetPackages(ctx)
 	if err != nil {
 		log.Error(ctx, "invalidateMeta: GetPackages", err, telemetry.File.Of(f.URI()))
 		return
 	}

 	for _, pkg := range pkgs {
 		for _, pgh := range pkg.GetHandles() {
 			uri := pgh.File().Identity().URI
 			if gof, _ := f.view.FindFile(ctx, uri).(*goFile); gof != nil {
 				gof.mu.Lock()
 				gof.meta = nil
 				gof.mu.Unlock()
 			}
 		}
 		f.view.mcache.mu.Lock()
 		delete(f.view.mcache.packages, packageID(pkg.ID()))
 		f.view.mcache.mu.Unlock()
 	}
 }

 // remove invalidates a package and its reverse dependencies in the view's
 // package cache. It is assumed that the caller has locked both the mutexes
 // of both the mcache and the pcache.
 func (v *view) remove(ctx context.Context, id packageID, seen map[packageID]struct{}) {
 	if _, ok := seen[id]; ok {
 		return
 	}
 	m, ok := v.mcache.packages[id]
 	if !ok {
 		return
 	}
 	seen[id] = struct{}{}
 	for parentID := range m.parents {
 		v.remove(ctx, parentID, seen)
 	}
 	// All of the files in the package may also be holding a pointer to the
 	// invalidated package.
 	for _, uri := range m.files {
 		f, err := v.findFile(uri)
 		if err != nil {
 			log.Error(ctx, "cannot find file", err, telemetry.File.Of(f.URI()))
 			continue
 		}
 		gof, ok := f.(*goFile)
 		if !ok {
 			log.Error(ctx, "non-Go file", nil, telemetry.File.Of(f.URI()))
 			continue
 		}
 		gof.mu.Lock()
 		// TODO: Ultimately, we shouldn't need this.
 		if cph, ok := gof.pkgs[id]; ok {
 			// Delete the package handle from the store.
 			v.session.cache.store.Delete(checkPackageKey{
 				id:     cph.ID(),
 				files:  hashParseKeys(cph.Files()),
 				config: hashConfig(cph.Config()),
 			})
 		}
 		delete(gof.pkgs, id)
 		gof.mu.Unlock()
 	}
 	return
 }

 // FindFile returns the file if the given URI is already a part of the view.
 func (v *view) FindFile(ctx context.Context, uri span.URI) source.File {
 	v.mu.Lock()
 	defer v.mu.Unlock()
 	f, err := v.findFile(uri)
 	if err != nil {
 		return nil
 	}
 	return f
 }

 // GetFile returns a File for the given URI. It will always succeed because it
 // adds the file to the managed set if needed.
 func (v *view) GetFile(ctx context.Context, uri span.URI) (source.File, error) {
 	v.mu.Lock()
 	defer v.mu.Unlock()

 	return v.getFile(ctx, uri)
 }

 // getFile is the unlocked internal implementation of GetFile.
 func (v *view) getFile(ctx context.Context, uri span.URI) (viewFile, error) {
 	if f, err := v.findFile(uri); err != nil {
 		return nil, err
 	} else if f != nil {
 		return f, nil
 	}
 	filename := uri.Filename()
 	var f viewFile
 	switch ext := filepath.Ext(filename); ext {
 	case ".mod":
 		f = &modFile{
 			fileBase: fileBase{
 				view:  v,
 				fname: filename,
 				kind:  source.Mod,
 			},
 		}
 	case ".sum":
 		f = &sumFile{
 			fileBase: fileBase{
 				view:  v,
 				fname: filename,
 				kind:  source.Sum,
 			},
 		}
 	default:
 		// Assume that all other files are Go files, regardless of extension.
 		f = &goFile{
 			fileBase: fileBase{
 				view:  v,
 				fname: filename,
 				kind:  source.Go,
 			},
 		}
 		v.session.filesWatchMap.Watch(uri, func() {
 			gof, ok := f.(*goFile)
 			if !ok {
 				return
 			}
 			gof.invalidateContent(ctx)
 		})
 	}
 	v.mapFile(uri, f)
 	return f, nil
 }

 // findFile checks the cache for any file matching the given uri.
 //
 // An error is only returned for an irreparable failure, for example, if the
 // filename in question does not exist.
 func (v *view) findFile(uri span.URI) (viewFile, error) {
 	if f := v.filesByURI[uri]; f != nil {
 		// a perfect match
 		return f, nil
 	}
 	// no exact match stored, time to do some real work
 	// check for any files with the same basename
 	fname := uri.Filename()
 	basename := basename(fname)
 	if candidates := v.filesByBase[basename]; candidates != nil {
 		pathStat, err := os.Stat(fname)
 		if os.IsNotExist(err) {
 			return nil, err
 		}
 		if err != nil {
 			return nil, nil // the file may exist, return without an error
 		}
 		for _, c := range candidates {
 			if cStat, err := os.Stat(c.filename()); err == nil {
 				if os.SameFile(pathStat, cStat) {
 					// same file, map it
 					v.mapFile(uri, c)
 					return c, nil
 				}
 			}
 		}
 	}
 	// no file with a matching name was found, it wasn't in our cache
 	return nil, nil
 }

 func (f *fileBase) addURI(uri span.URI) int {
 	f.uris = append(f.uris, uri)
 	return len(f.uris)
 }

 func (v *view) mapFile(uri span.URI, f viewFile) {
 	v.filesByURI[uri] = f
 	if f.addURI(uri) == 1 {
 		basename := basename(f.filename())
 		v.filesByBase[basename] = append(v.filesByBase[basename], f)
 	}
 }

 type debugView struct{ *view }

 func (v debugView) ID() string             { return v.id }
 func (v debugView) Session() debug.Session { return debugSession{v.session} }
	// Copyright 2018 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"
	"go/ast"
	"go/token"
	"go/types"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"

	"golang.org/x/tools/go/packages"
	"golang.org/x/tools/internal/imports"
	"golang.org/x/tools/internal/lsp/debug"
	"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"
	)

	type view struct {
	session *session
	id string

	options source.Options

	// mu protects all mutable state of the view.
	mu sync.Mutex

	// baseCtx is the context handed to NewView. This is the parent of all
	// background contexts created for this view.
	baseCtx context.Context

	// backgroundCtx is the current context used by background tasks initiated
	// by the view.
	backgroundCtx context.Context

	// cancel is called when all action being performed by the current view
	// should be stopped.
	cancel context.CancelFunc

	// Name is the user visible name of this view.
	name string

	// Folder is the root of this view.
	folder span.URI

	// process is the process env for this view.
	// Note: this contains cached module and filesystem state.
	//
	// TODO(suzmue): the state cached in the process env is specific to each view,
	// however, there is state that can be shared between views that is not currently
	// cached, like the module cache.
	processEnv *imports.ProcessEnv

	// modFileVersions stores the last seen versions of the module files that are used
	// by processEnvs resolver.
	// TODO(suzmue): These versions may not actually be on disk.
	modFileVersions map[string]string

	// keep track of files by uri and by basename, a single file may be mapped
	// to multiple uris, and the same basename may map to multiple files
	filesByURI map[span.URI]viewFile
	filesByBase map[string][]viewFile

	// mcache caches metadata for the packages of the opened files in a view.
	mcache *metadataCache

	// builtin is used to resolve builtin types.
	builtin *builtinPkg

	// ignoredURIs is the set of URIs of files that we ignore.
	ignoredURIsMu sync.Mutex
	ignoredURIs map[span.URI]struct{}
	}

	type metadataCache struct {
	mu sync.Mutex // guards both maps
	packages map[packageID]*metadata
	}

	type metadata struct {
	id packageID
	pkgPath packagePath
	name string
	files []span.URI
	key string
	typesSizes types.Sizes
	parents map[packageID]bool
	children map[packageID]*metadata
	errors []packages.Error
	}

	func (v *view) Session() source.Session {
	return v.session
	}

	// Name returns the user visible name of this view.
	func (v *view) Name() string {
	return v.name
	}

	// Folder returns the root of this view.
	func (v *view) Folder() span.URI {
	return v.folder
	}

	func (v *view) Options() source.Options {
	return v.options
	}

	func (v *view) SetOptions(options source.Options) {
	v.options = options
	}

	// Config returns the configuration used for the view's interaction with the
	// go/packages API. It is shared across all views.
	func (v view) Config(ctx context.Context) packages.Config {
	// TODO: Should we cache the config and/or overlay somewhere?
	return &packages.Config{
	Dir: v.folder.Filename(),
	Env: v.options.Env,
	BuildFlags: v.options.BuildFlags,
	Mode: packages.NeedName \|
	packages.NeedFiles \|
	packages.NeedCompiledGoFiles \|
	packages.NeedImports \|
	packages.NeedDeps \|
	packages.NeedTypesSizes,
	Fset: v.session.cache.fset,
	Overlay: v.session.buildOverlay(),
	ParseFile: func(token.FileSet, string, []byte) (ast.File, error) {
	panic("go/packages must not be used to parse files")
	},
	Logf: func(format string, args ...interface{}) {
	log.Print(ctx, fmt.Sprintf(format, args...))
	},
	Tests: true,
	}
	}

	func (v view) RunProcessEnvFunc(ctx context.Context, fn func(imports.Options) error, opts *imports.Options) error {
	v.mu.Lock()
	defer v.mu.Unlock()
	if v.processEnv == nil {
	var err error
	if v.processEnv, err = v.buildProcessEnv(ctx); err != nil {
	return err
	}
	}

	// Before running the user provided function, clear caches in the resolver.
	if v.modFilesChanged() {
	if r, ok := v.processEnv.GetResolver().(*imports.ModuleResolver); ok {
	// Clear the resolver cache and set Initialized to false.
	r.Initialized = false
	r.Main = nil
	r.ModsByModPath = nil
	r.ModsByDir = nil
	// Reset the modFileVersions.
	v.modFileVersions = nil
	}
	}

	// Run the user function.
	opts.Env = v.processEnv
	if err := fn(opts); err != nil {
	return err
	}

	// If applicable, store the file versions of the 'go.mod' files that are
	// looked at by the resolver.
	v.storeModFileVersions()

	return nil
	}

	func (v view) buildProcessEnv(ctx context.Context) (imports.ProcessEnv, error) {
	cfg := v.Config(ctx)
	env := &imports.ProcessEnv{
	WorkingDir: cfg.Dir,
	Logf: func(format string, args ...interface{}) {
	log.Print(ctx, fmt.Sprintf(format, args...))
	},
	}
	for _, kv := range cfg.Env {
	split := strings.Split(kv, "=")
	if len(split) < 2 {
	continue
	}
	switch split[0] {
	case "GOPATH":
	env.GOPATH = split[1]
	case "GOROOT":
	env.GOROOT = split[1]
	case "GO111MODULE":
	env.GO111MODULE = split[1]
	case "GOPROXY":
	env.GOPROXY = split[1]
	case "GOFLAGS":
	env.GOFLAGS = split[1]
	case "GOSUMDB":
	env.GOSUMDB = split[1]
	}
	}

	if env.GOPATH == "" {
	cmd := exec.CommandContext(ctx, "go", "env", "GOPATH")
	cmd.Env = cfg.Env
	if out, err := cmd.CombinedOutput(); err != nil {
	return nil, err
	} else {
	env.GOPATH = strings.TrimSpace(string(out))
	}
	}
	return env, nil
	}

	func (v *view) modFilesChanged() bool {
	// Check the versions of the 'go.mod' files of the main module
	// and modules included by a replace directive. Return true if
	// any of these file versions do not match.
	for filename, version := range v.modFileVersions {
	if version != v.fileVersion(filename) {
	return true
	}
	}
	return false
	}

	func (v *view) storeModFileVersions() {
	// Store the mod files versions, if we are using a ModuleResolver.
	r, moduleMode := v.processEnv.GetResolver().(*imports.ModuleResolver)
	if !moduleMode \|\| !r.Initialized {
	return
	}
	v.modFileVersions = make(map[string]string)

	// Get the file versions of the 'go.mod' files of the main module
	// and modules included by a replace directive in the resolver.
	for _, mod := range r.ModsByModPath {
	if (mod.Main \|\| mod.Replace != nil) && mod.GoMod != "" {
	v.modFileVersions[mod.GoMod] = v.fileVersion(mod.GoMod)
	}
	}
	}

	func (v *view) fileVersion(filename string) string {
	uri := span.FileURI(filename)
	f := v.session.GetFile(uri)
	return f.Identity().Version
	}

	func (v *view) Shutdown(ctx context.Context) {
	v.session.removeView(ctx, v)
	}

	func (v *view) shutdown(context.Context) {
	v.mu.Lock()
	defer v.mu.Unlock()
	if v.cancel != nil {
	v.cancel()
	v.cancel = nil
	}
	debug.DropView(debugView{v})
	}

	// Ignore checks if the given URI is a URI we ignore.
	// As of right now, we only ignore files in the "builtin" package.
	func (v *view) Ignore(uri span.URI) bool {
	v.ignoredURIsMu.Lock()
	defer v.ignoredURIsMu.Unlock()

	_, ok := v.ignoredURIs[uri]
	return ok
	}

	func (v *view) BackgroundContext() context.Context {
	v.mu.Lock()
	defer v.mu.Unlock()

	return v.backgroundCtx
	}

	func (v *view) BuiltinPackage() source.BuiltinPackage {
	return v.builtin
	}

	// SetContent sets the overlay contents for a file.
	func (v *view) SetContent(ctx context.Context, uri span.URI, content []byte) (bool, error) {
	v.mu.Lock()
	defer v.mu.Unlock()

	// Cancel all still-running previous requests, since they would be
	// operating on stale data.
	v.cancel()
	v.backgroundCtx, v.cancel = context.WithCancel(v.baseCtx)

	if !v.Ignore(uri) {
	return v.session.SetOverlay(uri, content), nil
	}
	return false, nil
	}

	// invalidateContent invalidates the content of a Go file,
	// including any position and type information that depends on it.
	func (f *goFile) invalidateContent(ctx context.Context) {
	// Mutex acquisition order here is important. It must match the order
	// in loadParseTypecheck to avoid deadlocks.
	f.view.mcache.mu.Lock()
	defer f.view.mcache.mu.Unlock()

	var toDelete []packageID
	f.mu.Lock()
	for id, cph := range f.pkgs {
	if cph != nil {
	toDelete = append(toDelete, id)
	}
	}
	f.mu.Unlock()

	f.handleMu.Lock()
	defer f.handleMu.Unlock()

	// Remove the package and all of its reverse dependencies from the cache.
	for _, id := range toDelete {
	f.view.remove(ctx, id, map[packageID]struct{}{})
	}

	f.handle = nil
	}

	// invalidateMeta invalidates package metadata for all files in f's
	// package. This forces f's package's metadata to be reloaded next
	// time the package is checked.
	func (f *goFile) invalidateMeta(ctx context.Context) {
	pkgs, err := f.GetPackages(ctx)
	if err != nil {
	log.Error(ctx, "invalidateMeta: GetPackages", err, telemetry.File.Of(f.URI()))
	return
	}

	for _, pkg := range pkgs {
	for _, pgh := range pkg.GetHandles() {
	uri := pgh.File().Identity().URI
	if gof, _ := f.view.FindFile(ctx, uri).(*goFile); gof != nil {
	gof.mu.Lock()
	gof.meta = nil
	gof.mu.Unlock()
	}
	}
	f.view.mcache.mu.Lock()
	delete(f.view.mcache.packages, packageID(pkg.ID()))
	f.view.mcache.mu.Unlock()
	}
	}

	// remove invalidates a package and its reverse dependencies in the view's
	// package cache. It is assumed that the caller has locked both the mutexes
	// of both the mcache and the pcache.
	func (v *view) remove(ctx context.Context, id packageID, seen map[packageID]struct{}) {
	if _, ok := seen[id]; ok {
	return
	}
	m, ok := v.mcache.packages[id]
	if !ok {
	return
	}
	seen[id] = struct{}{}
	for parentID := range m.parents {
	v.remove(ctx, parentID, seen)
	}
	// All of the files in the package may also be holding a pointer to the
	// invalidated package.
	for _, uri := range m.files {
	f, err := v.findFile(uri)
	if err != nil {
	log.Error(ctx, "cannot find file", err, telemetry.File.Of(f.URI()))
	continue
	}
	gof, ok := f.(*goFile)
	if !ok {
	log.Error(ctx, "non-Go file", nil, telemetry.File.Of(f.URI()))
	continue
	}
	gof.mu.Lock()
	// TODO: Ultimately, we shouldn't need this.
	if cph, ok := gof.pkgs[id]; ok {
	// Delete the package handle from the store.
	v.session.cache.store.Delete(checkPackageKey{
	id: cph.ID(),
	files: hashParseKeys(cph.Files()),
	config: hashConfig(cph.Config()),
	})
	}
	delete(gof.pkgs, id)
	gof.mu.Unlock()
	}
	return
	}

	// FindFile returns the file if the given URI is already a part of the view.
	func (v *view) FindFile(ctx context.Context, uri span.URI) source.File {
	v.mu.Lock()
	defer v.mu.Unlock()
	f, err := v.findFile(uri)
	if err != nil {
	return nil
	}
	return f
	}

	// GetFile returns a File for the given URI. It will always succeed because it
	// adds the file to the managed set if needed.
	func (v *view) GetFile(ctx context.Context, uri span.URI) (source.File, error) {
	v.mu.Lock()
	defer v.mu.Unlock()

	return v.getFile(ctx, uri)
	}

	// getFile is the unlocked internal implementation of GetFile.
	func (v *view) getFile(ctx context.Context, uri span.URI) (viewFile, error) {
	if f, err := v.findFile(uri); err != nil {
	return nil, err
	} else if f != nil {
	return f, nil
	}
	filename := uri.Filename()
	var f viewFile
	switch ext := filepath.Ext(filename); ext {
	case ".mod":
	f = &modFile{
	fileBase: fileBase{
	view: v,
	fname: filename,
	kind: source.Mod,
	},
	}
	case ".sum":
	f = &sumFile{
	fileBase: fileBase{
	view: v,
	fname: filename,
	kind: source.Sum,
	},
	}
	default:
	// Assume that all other files are Go files, regardless of extension.
	f = &goFile{
	fileBase: fileBase{
	view: v,
	fname: filename,
	kind: source.Go,
	},
	}
	v.session.filesWatchMap.Watch(uri, func() {
	gof, ok := f.(*goFile)
	if !ok {
	return
	}
	gof.invalidateContent(ctx)
	})
	}
	v.mapFile(uri, f)
	return f, nil
	}

	// findFile checks the cache for any file matching the given uri.
	//
	// An error is only returned for an irreparable failure, for example, if the
	// filename in question does not exist.
	func (v *view) findFile(uri span.URI) (viewFile, error) {
	if f := v.filesByURI[uri]; f != nil {
	// a perfect match
	return f, nil
	}
	// no exact match stored, time to do some real work
	// check for any files with the same basename
	fname := uri.Filename()
	basename := basename(fname)
	if candidates := v.filesByBase[basename]; candidates != nil {
	pathStat, err := os.Stat(fname)
	if os.IsNotExist(err) {
	return nil, err
	}
	if err != nil {
	return nil, nil // the file may exist, return without an error
	}
	for _, c := range candidates {
	if cStat, err := os.Stat(c.filename()); err == nil {
	if os.SameFile(pathStat, cStat) {
	// same file, map it
	v.mapFile(uri, c)
	return c, nil
	}
	}
	}
	}
	// no file with a matching name was found, it wasn't in our cache
	return nil, nil
	}

	func (f *fileBase) addURI(uri span.URI) int {
	f.uris = append(f.uris, uri)
	return len(f.uris)
	}

	func (v *view) mapFile(uri span.URI, f viewFile) {
	v.filesByURI[uri] = f
	if f.addURI(uri) == 1 {
	basename := basename(f.filename())
	v.filesByBase[basename] = append(v.filesByBase[basename], f)
	}
	}

	type debugView struct{ *view }

	func (v debugView) ID() string { return v.id }
	func (v debugView) Session() debug.Session { return debugSession{v.session} }