| // 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" |
| "crypto/sha1" |
| "fmt" |
| "go/ast" |
| "go/token" |
| "go/types" |
| "html/template" |
| "io/ioutil" |
| "os" |
| "reflect" |
| "sort" |
| "strconv" |
| "sync/atomic" |
| "time" |
| |
| "golang.org/x/tools/internal/event" |
| "golang.org/x/tools/internal/lsp/debug/tag" |
| "golang.org/x/tools/internal/lsp/source" |
| "golang.org/x/tools/internal/memoize" |
| "golang.org/x/tools/internal/span" |
| errors "golang.org/x/xerrors" |
| ) |
| |
| func New(ctx context.Context, options func(*source.Options)) *Cache { |
| index := atomic.AddInt64(&cacheIndex, 1) |
| c := &Cache{ |
| id: strconv.FormatInt(index, 10), |
| fset: token.NewFileSet(), |
| options: options, |
| } |
| return c |
| } |
| |
| type Cache struct { |
| id string |
| fset *token.FileSet |
| options func(*source.Options) |
| |
| store memoize.Store |
| } |
| |
| type fileKey struct { |
| uri span.URI |
| modTime time.Time |
| } |
| |
| type fileHandle struct { |
| uri span.URI |
| memoize.NoCopy |
| bytes []byte |
| hash string |
| err error |
| } |
| |
| func (c *Cache) getFile(ctx context.Context, uri span.URI) (*fileHandle, error) { |
| var modTime time.Time |
| if fi, err := os.Stat(uri.Filename()); err == nil { |
| modTime = fi.ModTime() |
| } |
| |
| key := fileKey{ |
| uri: uri, |
| modTime: modTime, |
| } |
| h := c.store.Bind(key, func(ctx context.Context) interface{} { |
| return readFile(ctx, uri, modTime) |
| }) |
| v := h.Get(ctx) |
| if v == nil { |
| return nil, ctx.Err() |
| } |
| return v.(*fileHandle), nil |
| } |
| |
| // ioLimit limits the number of parallel file reads per process. |
| var ioLimit = make(chan struct{}, 128) |
| |
| func readFile(ctx context.Context, uri span.URI, origTime time.Time) *fileHandle { |
| ctx, done := event.Start(ctx, "cache.getFile", tag.File.Of(uri.Filename())) |
| _ = ctx |
| defer done() |
| |
| ioLimit <- struct{}{} |
| defer func() { <-ioLimit }() |
| |
| var modTime time.Time |
| if fi, err := os.Stat(uri.Filename()); err == nil { |
| modTime = fi.ModTime() |
| } |
| |
| if modTime != origTime { |
| return &fileHandle{err: errors.Errorf("%s: file has been modified", uri.Filename())} |
| } |
| data, err := ioutil.ReadFile(uri.Filename()) |
| if err != nil { |
| return &fileHandle{err: err} |
| } |
| return &fileHandle{ |
| uri: uri, |
| bytes: data, |
| hash: hashContents(data), |
| } |
| } |
| |
| func (c *Cache) NewSession(ctx context.Context) *Session { |
| index := atomic.AddInt64(&sessionIndex, 1) |
| s := &Session{ |
| cache: c, |
| id: strconv.FormatInt(index, 10), |
| options: source.DefaultOptions(), |
| overlays: make(map[span.URI]*overlay), |
| } |
| event.Log(ctx, "New session", KeyCreateSession.Of(s)) |
| return s |
| } |
| |
| func (c *Cache) FileSet() *token.FileSet { |
| return c.fset |
| } |
| |
| func (h *fileHandle) URI() span.URI { |
| return h.uri |
| } |
| |
| func (h *fileHandle) Kind() source.FileKind { |
| return source.DetectLanguage("", h.uri.Filename()) |
| } |
| |
| func (h *fileHandle) Version() float64 { |
| return 0 |
| } |
| |
| func (h *fileHandle) Identity() source.FileIdentity { |
| return source.FileIdentity{ |
| URI: h.uri, |
| Identifier: h.hash, |
| Kind: h.Kind(), |
| } |
| } |
| |
| func (h *fileHandle) Read() ([]byte, error) { |
| return h.bytes, h.err |
| } |
| |
| func hashContents(contents []byte) string { |
| // TODO: consider whether sha1 is the best choice here |
| // This hash is used for internal identity detection only |
| return fmt.Sprintf("%x", sha1.Sum(contents)) |
| } |
| |
| var cacheIndex, sessionIndex, viewIndex int64 |
| |
| func (c *Cache) ID() string { return c.id } |
| func (c *Cache) MemStats() map[reflect.Type]int { return c.store.Stats() } |
| |
| type packageStat struct { |
| id packageID |
| mode source.ParseMode |
| file int64 |
| ast int64 |
| types int64 |
| typesInfo int64 |
| total int64 |
| } |
| |
| func (c *Cache) PackageStats(withNames bool) template.HTML { |
| var packageStats []packageStat |
| c.store.DebugOnlyIterate(func(k, v interface{}) { |
| switch k.(type) { |
| case packageHandleKey: |
| v := v.(*packageData) |
| if v.pkg == nil { |
| break |
| } |
| var typsCost, typInfoCost int64 |
| if v.pkg.types != nil { |
| typsCost = typesCost(v.pkg.types.Scope()) |
| } |
| if v.pkg.typesInfo != nil { |
| typInfoCost = typesInfoCost(v.pkg.typesInfo) |
| } |
| stat := packageStat{ |
| id: v.pkg.id, |
| mode: v.pkg.mode, |
| types: typsCost, |
| typesInfo: typInfoCost, |
| } |
| for _, f := range v.pkg.compiledGoFiles { |
| fvi := f.handle.Cached() |
| if fvi == nil { |
| continue |
| } |
| fv := fvi.(*parseGoData) |
| stat.file += int64(len(fv.src)) |
| stat.ast += astCost(fv.ast) |
| } |
| stat.total = stat.file + stat.ast + stat.types + stat.typesInfo |
| packageStats = append(packageStats, stat) |
| } |
| }) |
| var totalCost int64 |
| for _, stat := range packageStats { |
| totalCost += stat.total |
| } |
| sort.Slice(packageStats, func(i, j int) bool { |
| return packageStats[i].total > packageStats[j].total |
| }) |
| html := "<table><thead><td>Name</td><td>total = file + ast + types + types info</td></thead>\n" |
| human := func(n int64) string { |
| return fmt.Sprintf("%.2f", float64(n)/(1024*1024)) |
| } |
| var printedCost int64 |
| for _, stat := range packageStats { |
| name := stat.id |
| if !withNames { |
| name = "-" |
| } |
| html += fmt.Sprintf("<tr><td>%v (%v)</td><td>%v = %v + %v + %v + %v</td></tr>\n", name, stat.mode, |
| human(stat.total), human(stat.file), human(stat.ast), human(stat.types), human(stat.typesInfo)) |
| printedCost += stat.total |
| if float64(printedCost) > float64(totalCost)*.9 { |
| break |
| } |
| } |
| html += "</table>\n" |
| return template.HTML(html) |
| } |
| |
| func astCost(f *ast.File) int64 { |
| var count int64 |
| ast.Inspect(f, func(n ast.Node) bool { |
| count += 32 // nodes are pretty small. |
| return true |
| }) |
| return count |
| } |
| |
| func typesCost(scope *types.Scope) int64 { |
| cost := 64 + int64(scope.Len())*128 // types.object looks pretty big |
| for i := 0; i < scope.NumChildren(); i++ { |
| cost += typesCost(scope.Child(i)) |
| } |
| return cost |
| } |
| |
| func typesInfoCost(info *types.Info) int64 { |
| // Most of these refer to existing objects, with the exception of InitOrder, Selections, and Types. |
| cost := 24*len(info.Defs) + |
| 32*len(info.Implicits) + |
| 256*len(info.InitOrder) + // these are big, but there aren't many of them. |
| 32*len(info.Scopes) + |
| 128*len(info.Selections) + // wild guess |
| 128*len(info.Types) + // wild guess |
| 32*len(info.Uses) |
| return int64(cost) |
| } |