blob: 4b97ee6366b11ee2d53fe3a43f2209cc963556e8 [file] [log] [blame]
// 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 implements the caching layer for gopls.
package cache
import (
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"path"
"path/filepath"
"reflect"
"regexp"
"sort"
"strings"
"sync"
"golang.org/x/mod/modfile"
"golang.org/x/mod/semver"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/gocommand"
"golang.org/x/tools/internal/imports"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/memoize"
"golang.org/x/tools/internal/span"
"golang.org/x/tools/internal/xcontext"
errors "golang.org/x/xerrors"
)
type View struct {
session *Session
id string
optionsMu sync.Mutex
options *source.Options
// mu protects most 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 folder with which this view was constructed.
folder span.URI
importsState *importsState
// 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]*fileBase
filesByBase map[string][]*fileBase
snapshotMu sync.Mutex
snapshot *snapshot
// initialized is closed when the view has been fully initialized. On
// initialization, the view's workspace packages are loaded. All of the
// fields below are set as part of initialization. If we failed to load, we
// only retry if the go.mod file changes, to avoid too many go/packages
// calls.
//
// When the view is created, initializeOnce is non-nil, initialized is
// open, and initCancelFirstAttempt can be used to terminate
// initialization. Once initialization completes, initializedErr may be set
// and initializeOnce becomes nil. If initializedErr is non-nil,
// initialization may be retried (depending on how files are changed). To
// indicate that initialization should be retried, initializeOnce will be
// set. The next time a caller requests workspace packages, the
// initialization will retry.
initialized chan struct{}
initCancelFirstAttempt context.CancelFunc
// initializationSema is used as a mutex to guard initializeOnce and
// initializedErr, which will be updated after each attempt to initialize
// the view. We use a channel instead of a mutex to avoid blocking when a
// context is canceled.
initializationSema chan struct{}
initializeOnce *sync.Once
initializedErr error
// workspaceInformation tracks various details about this view's
// environment variables, go version, and use of modules.
workspaceInformation
}
type workspaceInformation struct {
// The Go version in use: X in Go 1.X.
goversion int
// hasGopackagesDriver is true if the user has a value set for the
// GOPACKAGESDRIVER environment variable or a gopackagesdriver binary on
// their machine.
hasGopackagesDriver bool
// `go env` variables that need to be tracked by gopls.
environmentVariables
// The value of GO111MODULE we want to run with.
go111module string
// goEnv is the `go env` output collected when a view is created.
// It includes the values of the environment variables above.
goEnv map[string]string
// rootURI is the rootURI directory of this view. If we are in GOPATH mode, this
// is just the folder. If we are in module mode, this is the module rootURI.
rootURI span.URI
}
type environmentVariables struct {
gocache, gopath, goprivate, gomodcache string
}
type workspaceMode int
const (
moduleMode workspaceMode = 1 << iota
// tempModfile indicates whether or not the -modfile flag should be used.
tempModfile
// usesWorkspaceModule indicates support for the experimental workspace module
// feature.
usesWorkspaceModule
)
type builtinPackageHandle struct {
handle *memoize.Handle
}
type builtinPackageData struct {
parsed *source.BuiltinPackage
err error
}
// fileBase holds the common functionality for all files.
// It is intended to be embedded in the file implementations
type fileBase struct {
uris []span.URI
fname string
view *View
}
func (f *fileBase) URI() span.URI {
return f.uris[0]
}
func (f *fileBase) filename() string {
return f.fname
}
func (f *fileBase) addURI(uri span.URI) int {
f.uris = append(f.uris, uri)
return len(f.uris)
}
func (v *View) ID() string { return v.id }
// tempModFile creates a temporary go.mod file based on the contents of the
// given go.mod file. It is the caller's responsibility to clean up the files
// when they are done using them.
func tempModFile(modFh source.FileHandle, gosum []byte) (tmpURI span.URI, cleanup func(), err error) {
filenameHash := hashContents([]byte(modFh.URI().Filename()))
tmpMod, err := ioutil.TempFile("", fmt.Sprintf("go.%s.*.mod", filenameHash))
if err != nil {
return "", nil, err
}
defer tmpMod.Close()
tmpURI = span.URIFromPath(tmpMod.Name())
tmpSumName := sumFilename(tmpURI)
content, err := modFh.Read()
if err != nil {
return "", nil, err
}
if _, err := tmpMod.Write(content); err != nil {
return "", nil, err
}
cleanup = func() {
_ = os.Remove(tmpSumName)
_ = os.Remove(tmpURI.Filename())
}
// Be careful to clean up if we return an error from this function.
defer func() {
if err != nil {
cleanup()
cleanup = nil
}
}()
// Create an analogous go.sum, if one exists.
if gosum != nil {
if err := ioutil.WriteFile(tmpSumName, gosum, 0655); err != nil {
return "", cleanup, err
}
}
return tmpURI, cleanup, nil
}
// Name returns the user visible name of this view.
func (v *View) Name() string {
return v.name
}
// Folder returns the folder at the base of this view.
func (v *View) Folder() span.URI {
return v.folder
}
func (v *View) Options() *source.Options {
v.optionsMu.Lock()
defer v.optionsMu.Unlock()
return v.options
}
func minorOptionsChange(a, b *source.Options) bool {
// Check if any of the settings that modify our understanding of files have been changed
if !reflect.DeepEqual(a.Env, b.Env) {
return false
}
aBuildFlags := make([]string, len(a.BuildFlags))
bBuildFlags := make([]string, len(b.BuildFlags))
copy(aBuildFlags, a.BuildFlags)
copy(bBuildFlags, b.BuildFlags)
sort.Strings(aBuildFlags)
sort.Strings(bBuildFlags)
// the rest of the options are benign
return reflect.DeepEqual(aBuildFlags, bBuildFlags)
}
func (v *View) SetOptions(ctx context.Context, options *source.Options) (source.View, error) {
// no need to rebuild the view if the options were not materially changed
v.optionsMu.Lock()
if minorOptionsChange(v.options, options) {
v.options = options
v.optionsMu.Unlock()
return v, nil
}
v.optionsMu.Unlock()
newView, err := v.session.updateView(ctx, v, options)
return newView, err
}
func (v *View) Rebuild(ctx context.Context) (source.Snapshot, func(), error) {
newView, err := v.session.updateView(ctx, v, v.Options())
if err != nil {
return nil, func() {}, err
}
snapshot, release := newView.Snapshot(ctx)
return snapshot, release, nil
}
func (s *snapshot) WriteEnv(ctx context.Context, w io.Writer) error {
s.view.optionsMu.Lock()
env := s.view.options.EnvSlice()
buildFlags := append([]string{}, s.view.options.BuildFlags...)
s.view.optionsMu.Unlock()
fullEnv := make(map[string]string)
for k, v := range s.view.goEnv {
fullEnv[k] = v
}
for _, v := range env {
s := strings.SplitN(v, "=", 2)
if len(s) != 2 {
continue
}
if _, ok := fullEnv[s[0]]; ok {
fullEnv[s[0]] = s[1]
}
}
goVersion, err := s.view.session.gocmdRunner.Run(ctx, gocommand.Invocation{
Verb: "version",
Env: env,
WorkingDir: s.view.rootURI.Filename(),
})
if err != nil {
return err
}
fmt.Fprintf(w, `go env for %v
(root %s)
(go version %s)
(valid build configuration = %v)
(build flags: %v)
`,
s.view.folder.Filename(),
s.view.rootURI.Filename(),
strings.TrimRight(goVersion.String(), "\n"),
s.ValidBuildConfiguration(),
buildFlags)
for k, v := range fullEnv {
fmt.Fprintf(w, "%s=%s\n", k, v)
}
return nil
}
func (s *snapshot) RunProcessEnvFunc(ctx context.Context, fn func(*imports.Options) error) error {
return s.view.importsState.runProcessEnvFunc(ctx, s, fn)
}
func (v *View) contains(uri span.URI) bool {
return strings.HasPrefix(string(uri), string(v.rootURI))
}
func (v *View) mapFile(uri span.URI, f *fileBase) {
v.filesByURI[uri] = f
if f.addURI(uri) == 1 {
basename := basename(f.filename())
v.filesByBase[basename] = append(v.filesByBase[basename], f)
}
}
func basename(filename string) string {
return strings.ToLower(filepath.Base(filename))
}
func (v *View) relevantChange(c source.FileModification) bool {
// If the file is known to the view, the change is relevant.
known := v.knownFile(c.URI)
// If the file is not known to the view, and the change is only on-disk,
// we should not invalidate the snapshot. This is necessary because Emacs
// sends didChangeWatchedFiles events for temp files.
if !known && c.OnDisk && (c.Action == source.Change || c.Action == source.Delete) {
return false
}
return v.contains(c.URI) || known
}
func (v *View) knownFile(uri span.URI) bool {
v.mu.Lock()
defer v.mu.Unlock()
f, err := v.findFile(uri)
return f != nil && err == nil
}
// 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(uri span.URI) (*fileBase, error) {
v.mu.Lock()
defer v.mu.Unlock()
f, err := v.findFile(uri)
if err != nil {
return nil, err
} else if f != nil {
return f, nil
}
f = &fileBase{
view: v,
fname: uri.Filename(),
}
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) (*fileBase, 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 (v *View) Shutdown(ctx context.Context) {
v.session.removeView(ctx, v)
}
func (v *View) shutdown(ctx context.Context) {
// Cancel the initial workspace load if it is still running.
v.initCancelFirstAttempt()
v.mu.Lock()
if v.cancel != nil {
v.cancel()
v.cancel = nil
}
v.mu.Unlock()
v.snapshotMu.Lock()
go v.snapshot.generation.Destroy()
v.snapshotMu.Unlock()
}
func (v *View) BackgroundContext() context.Context {
v.mu.Lock()
defer v.mu.Unlock()
return v.backgroundCtx
}
func (s *snapshot) IgnoredFile(uri span.URI) bool {
filename := uri.Filename()
var prefixes []string
if len(s.workspace.activeModFiles()) == 0 {
for _, entry := range filepath.SplitList(s.view.gopath) {
prefixes = append(prefixes, filepath.Join(entry, "src"))
}
} else {
prefixes = append(prefixes, s.view.gomodcache)
for m := range s.workspace.activeModFiles() {
prefixes = append(prefixes, dirURI(m).Filename())
}
}
for _, prefix := range prefixes {
if strings.HasPrefix(filename, prefix) {
return checkIgnored(filename[len(prefix):])
}
}
return false
}
// checkIgnored implements go list's exclusion rules. go help list:
// Directory and file names that begin with "." or "_" are ignored
// by the go tool, as are directories named "testdata".
func checkIgnored(suffix string) bool {
for _, component := range strings.Split(suffix, string(filepath.Separator)) {
if len(component) == 0 {
continue
}
if component[0] == '.' || component[0] == '_' || component == "testdata" {
return true
}
}
return false
}
func (v *View) Snapshot(ctx context.Context) (source.Snapshot, func()) {
v.snapshotMu.Lock()
defer v.snapshotMu.Unlock()
return v.snapshot, v.snapshot.generation.Acquire(ctx)
}
func (s *snapshot) initialize(ctx context.Context, firstAttempt bool) {
select {
case <-ctx.Done():
return
case s.view.initializationSema <- struct{}{}:
}
defer func() {
<-s.view.initializationSema
}()
if s.view.initializeOnce == nil {
return
}
s.view.initializeOnce.Do(func() {
defer func() {
s.view.initializeOnce = nil
if firstAttempt {
close(s.view.initialized)
}
}()
// If we have multiple modules, we need to load them by paths.
var scopes []interface{}
var modErrors *source.ErrorList
addError := func(uri span.URI, err error) {
if modErrors == nil {
modErrors = &source.ErrorList{}
}
*modErrors = append(*modErrors, &source.Error{
URI: uri,
Category: "compiler",
Kind: source.ListError,
Message: err.Error(),
})
}
for modURI := range s.workspace.activeModFiles() {
fh, err := s.GetFile(ctx, modURI)
if err != nil {
addError(modURI, err)
continue
}
parsed, err := s.ParseMod(ctx, fh)
if err != nil {
addError(modURI, err)
continue
}
if parsed.File == nil || parsed.File.Module == nil {
addError(modURI, fmt.Errorf("no module path for %s", modURI))
continue
}
path := parsed.File.Module.Mod.Path
scopes = append(scopes, moduleLoadScope(path))
}
if len(scopes) == 0 {
scopes = append(scopes, viewLoadScope("LOAD_VIEW"))
}
err := s.load(ctx, append(scopes, packagePath("builtin"))...)
if ctx.Err() != nil {
return
}
if err != nil {
event.Error(ctx, "initial workspace load failed", err)
if modErrors != nil {
s.view.initializedErr = errors.Errorf("errors loading modules: %v: %w", err, modErrors)
} else {
s.view.initializedErr = err
}
}
})
}
// invalidateContent invalidates the content of a Go file,
// including any position and type information that depends on it.
// It returns true if we were already tracking the given file, false otherwise.
func (v *View) invalidateContent(ctx context.Context, changes map[span.URI]*fileChange, forceReloadMetadata bool) (source.Snapshot, func()) {
// Detach the context so that content invalidation cannot be canceled.
ctx = xcontext.Detach(ctx)
// Cancel all still-running previous requests, since they would be
// operating on stale data.
v.cancelBackground()
// Do not clone a snapshot until its view has finished initializing.
v.snapshot.AwaitInitialized(ctx)
// This should be the only time we hold the view's snapshot lock for any period of time.
v.snapshotMu.Lock()
defer v.snapshotMu.Unlock()
oldSnapshot := v.snapshot
var reinitialize reinitializeView
v.snapshot, reinitialize = oldSnapshot.clone(ctx, changes, forceReloadMetadata)
go oldSnapshot.generation.Destroy()
if reinitialize == maybeReinit || reinitialize == definitelyReinit {
v.reinitialize(reinitialize == definitelyReinit)
}
return v.snapshot, v.snapshot.generation.Acquire(ctx)
}
func (v *View) cancelBackground() {
v.mu.Lock()
defer v.mu.Unlock()
if v.cancel == nil {
// this can happen during shutdown
return
}
v.cancel()
v.backgroundCtx, v.cancel = context.WithCancel(v.baseCtx)
}
func (v *View) reinitialize(force bool) {
v.initializationSema <- struct{}{}
defer func() {
<-v.initializationSema
}()
if !force && v.initializedErr == nil {
return
}
var once sync.Once
v.initializeOnce = &once
}
func (s *Session) getWorkspaceInformation(ctx context.Context, folder span.URI, options *source.Options) (*workspaceInformation, error) {
if err := checkPathCase(folder.Filename()); err != nil {
return nil, errors.Errorf("invalid workspace configuration: %w", err)
}
var err error
inv := gocommand.Invocation{
WorkingDir: folder.Filename(),
Env: options.EnvSlice(),
}
goversion, err := gocommand.GoVersion(ctx, inv, s.gocmdRunner)
if err != nil {
return nil, err
}
go111module := os.Getenv("GO111MODULE")
if v, ok := options.Env["GO111MODULE"]; ok {
go111module = v
}
// If using 1.16, change the default back to auto. The primary effect of
// GO111MODULE=on is to break GOPATH, which we aren't too interested in.
if goversion >= 16 && go111module == "" {
go111module = "auto"
}
// Make sure to get the `go env` before continuing with initialization.
envVars, env, err := s.getGoEnv(ctx, folder.Filename(), append(options.EnvSlice(), "GO111MODULE="+go111module))
if err != nil {
return nil, err
}
// The value of GOPACKAGESDRIVER is not returned through the go command.
gopackagesdriver := os.Getenv("GOPACKAGESDRIVER")
for _, s := range env {
split := strings.SplitN(s, "=", 2)
if split[0] == "GOPACKAGESDRIVER" {
gopackagesdriver = split[1]
}
}
// A user may also have a gopackagesdriver binary on their machine, which
// works the same way as setting GOPACKAGESDRIVER.
tool, _ := exec.LookPath("gopackagesdriver")
hasGopackagesDriver := gopackagesdriver != "off" && (gopackagesdriver != "" || tool != "")
root := folder
if options.ExpandWorkspaceToModule {
wsRoot, err := findWorkspaceRoot(ctx, root, s)
if err != nil {
return nil, err
}
if wsRoot != "" {
root = wsRoot
}
}
return &workspaceInformation{
hasGopackagesDriver: hasGopackagesDriver,
go111module: go111module,
goversion: goversion,
rootURI: root,
environmentVariables: envVars,
goEnv: env,
}, nil
}
func findWorkspaceRoot(ctx context.Context, folder span.URI, fs source.FileSource) (span.URI, error) {
for _, basename := range []string{"gopls.mod", "go.mod"} {
dir, err := findRootPattern(ctx, folder, basename, fs)
if err != nil {
return "", errors.Errorf("finding %s: %w", basename, err)
}
if dir != "" {
return dir, nil
}
}
return "", nil
}
func findRootPattern(ctx context.Context, folder span.URI, basename string, fs source.FileSource) (span.URI, error) {
dir := folder.Filename()
for dir != "" {
target := filepath.Join(dir, basename)
exists, err := fileExists(ctx, span.URIFromPath(target), fs)
if err != nil {
return "", err
}
if exists {
return span.URIFromPath(dir), nil
}
next, _ := filepath.Split(dir)
if next == dir {
break
}
dir = next
}
return "", nil
}
// OS-specific path case check, for case-insensitive filesystems.
var checkPathCase = defaultCheckPathCase
func defaultCheckPathCase(path string) error {
return nil
}
func validBuildConfiguration(folder span.URI, ws *workspaceInformation, modFiles map[span.URI]struct{}) bool {
// Since we only really understand the `go` command, if the user has a
// different GOPACKAGESDRIVER, assume that their configuration is valid.
if ws.hasGopackagesDriver {
return true
}
// Check if the user is working within a module or if we have found
// multiple modules in the workspace.
if len(modFiles) > 0 {
return true
}
// The user may have a multiple directories in their GOPATH.
// Check if the workspace is within any of them.
for _, gp := range filepath.SplitList(ws.gopath) {
if isSubdirectory(filepath.Join(gp, "src"), folder.Filename()) {
return true
}
}
return false
}
func isSubdirectory(root, leaf string) bool {
rel, err := filepath.Rel(root, leaf)
return err == nil && !strings.HasPrefix(rel, "..")
}
// getGoEnv gets the view's various GO* values.
func (s *Session) getGoEnv(ctx context.Context, folder string, configEnv []string) (environmentVariables, map[string]string, error) {
envVars := environmentVariables{}
vars := map[string]*string{
"GOCACHE": &envVars.gocache,
"GOPATH": &envVars.gopath,
"GOPRIVATE": &envVars.goprivate,
"GOMODCACHE": &envVars.gomodcache,
}
// We can save ~200 ms by requesting only the variables we care about.
args := append([]string{"-json"}, imports.RequiredGoEnvVars...)
for k := range vars {
args = append(args, k)
}
inv := gocommand.Invocation{
Verb: "env",
Args: args,
Env: configEnv,
WorkingDir: folder,
}
// Don't go through runGoCommand, as we don't need a temporary -modfile to
// run `go env`.
stdout, err := s.gocmdRunner.Run(ctx, inv)
if err != nil {
return environmentVariables{}, nil, err
}
env := make(map[string]string)
if err := json.Unmarshal(stdout.Bytes(), &env); err != nil {
return environmentVariables{}, nil, err
}
for key, ptr := range vars {
*ptr = env[key]
}
// Old versions of Go don't have GOMODCACHE, so emulate it.
if envVars.gomodcache == "" && envVars.gopath != "" {
envVars.gomodcache = filepath.Join(filepath.SplitList(envVars.gopath)[0], "pkg/mod")
}
return envVars, env, err
}
func (v *View) IsGoPrivatePath(target string) bool {
return globsMatchPath(v.goprivate, target)
}
// Copied from
// https://cs.opensource.google/go/go/+/master:src/cmd/go/internal/str/path.go;l=58;drc=2910c5b4a01a573ebc97744890a07c1a3122c67a
func globsMatchPath(globs, target string) bool {
for globs != "" {
// Extract next non-empty glob in comma-separated list.
var glob string
if i := strings.Index(globs, ","); i >= 0 {
glob, globs = globs[:i], globs[i+1:]
} else {
glob, globs = globs, ""
}
if glob == "" {
continue
}
// A glob with N+1 path elements (N slashes) needs to be matched
// against the first N+1 path elements of target,
// which end just before the N+1'th slash.
n := strings.Count(glob, "/")
prefix := target
// Walk target, counting slashes, truncating at the N+1'th slash.
for i := 0; i < len(target); i++ {
if target[i] == '/' {
if n == 0 {
prefix = target[:i]
break
}
n--
}
}
if n > 0 {
// Not enough prefix elements.
continue
}
matched, _ := path.Match(glob, prefix)
if matched {
return true
}
}
return false
}
var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
// TODO(rstambler): Consolidate modURI and modContent back into a FileHandle
// after we have a version of the workspace go.mod file on disk. Getting a
// FileHandle from the cache for temporary files is problematic, since we
// cannot delete it.
func (s *snapshot) needsModEqualsMod(ctx context.Context, modURI span.URI, modContent []byte) (bool, error) {
if s.view.goversion < 16 || s.workspaceMode()&moduleMode == 0 {
return false, nil
}
matches := modFlagRegexp.FindStringSubmatch(s.view.goEnv["GOFLAGS"])
var modFlag string
if len(matches) != 0 {
modFlag = matches[1]
}
if modFlag != "" {
// Don't override an explicit '-mod=vendor' argument.
// We do want to override '-mod=readonly': it would break various module code lenses,
// and on 1.16 we know -modfile is available, so we won't mess with go.mod anyway.
return modFlag == "vendor", nil
}
modFile, err := modfile.Parse(modURI.Filename(), modContent, nil)
if err != nil {
return false, err
}
if fi, err := os.Stat(filepath.Join(s.view.rootURI.Filename(), "vendor")); err != nil || !fi.IsDir() {
return true, nil
}
vendorEnabled := modFile.Go != nil && modFile.Go.Version != "" && semver.Compare("v"+modFile.Go.Version, "v1.14") >= 0
return !vendorEnabled, nil
}