| // 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" |
| |
| "golang.org/x/tools/internal/lsp/source" |
| "golang.org/x/tools/internal/span" |
| errors "golang.org/x/xerrors" |
| ) |
| |
| type overlay struct { |
| session *session |
| uri span.URI |
| text []byte |
| hash string |
| version float64 |
| 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 |
| } |
| |
| func (o *overlay) FileSystem() source.FileSystem { |
| return o.session |
| } |
| |
| func (o *overlay) Identity() source.FileIdentity { |
| return source.FileIdentity{ |
| URI: o.uri, |
| Identifier: o.hash, |
| Version: o.version, |
| Kind: o.kind, |
| } |
| } |
| func (o *overlay) Read(ctx context.Context) ([]byte, string, error) { |
| return o.text, o.hash, nil |
| } |
| |
| func (s *session) updateOverlay(ctx context.Context, c source.FileModification) error { |
| s.overlayMu.Lock() |
| defer s.overlayMu.Unlock() |
| |
| o, ok := s.overlays[c.URI] |
| |
| // Determine the file kind on open, otherwise, assume it has been cached. |
| var kind source.FileKind |
| switch c.Action { |
| case source.Open: |
| kind = source.DetectLanguage(c.LanguageID, c.URI.Filename()) |
| default: |
| if !ok { |
| return errors.Errorf("updateOverlay: modifying unopened overlay %v", c.URI) |
| } |
| kind = o.kind |
| } |
| if kind == source.UnknownKind { |
| return errors.Errorf("updateOverlay: unknown file kind for %s", c.URI) |
| } |
| |
| // Closing a file just deletes its overlay. |
| if c.Action == source.Close { |
| delete(s.overlays, c.URI) |
| return nil |
| } |
| |
| // If the file is on disk, check if its content is the same as the overlay. |
| text := c.Text |
| if text == nil { |
| text = o.text |
| } |
| hash := hashContents(text) |
| var sameContentOnDisk bool |
| switch c.Action { |
| case source.Open: |
| _, h, err := s.cache.GetFile(c.URI, kind).Read(ctx) |
| sameContentOnDisk = (err == nil && h == hash) |
| case source.Save: |
| // Make sure the version and content (if present) is the same. |
| if o.version != c.Version { |
| return errors.Errorf("updateOverlay: saving %s at version %v, currently at %v", c.URI, c.Version, o.version) |
| } |
| if c.Text != nil && o.hash != hash { |
| return errors.Errorf("updateOverlay: overlay %s changed on save", c.URI) |
| } |
| sameContentOnDisk = true |
| } |
| s.overlays[c.URI] = &overlay{ |
| session: s, |
| uri: c.URI, |
| version: c.Version, |
| text: text, |
| kind: kind, |
| hash: hash, |
| sameContentOnDisk: sameContentOnDisk, |
| } |
| return nil |
| } |
| |
| 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 { |
| // TODO(rstambler): Make sure not to send overlays outside of the current view. |
| if overlay.sameContentOnDisk { |
| continue |
| } |
| overlays[uri.Filename()] = overlay.text |
| } |
| return overlays |
| } |