1 files changed, 78 insertions, 0 deletions
diff --git a/gopls/internal/lsp/rename.go b/gopls/internal/lsp/rename.go
new file mode 100644
index 000000000..7111e92dc
--- /dev/null
+++ b/gopls/internal/lsp/rename.go
@@ -0,0 +1,78 @@
+// 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 lsp
+
+import (
+	"context"
+	"path/filepath"
+
+	"golang.org/x/tools/gopls/internal/lsp/protocol"
+	"golang.org/x/tools/gopls/internal/lsp/source"
+)
+
+func (s *Server) rename(ctx context.Context, params *protocol.RenameParams) (*protocol.WorkspaceEdit, error) {
+	snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.Go)
+	defer release()
+	if !ok {
+		return nil, err
+	}
+	// Because we don't handle directory renaming within source.Rename, source.Rename returns
+	// boolean value isPkgRenaming to determine whether an DocumentChanges of type RenameFile should
+	// be added to the return protocol.WorkspaceEdit value.
+	edits, isPkgRenaming, err := source.Rename(ctx, snapshot, fh, params.Position, params.NewName)
+	if err != nil {
+		return nil, err
+	}
+
+	var docChanges []protocol.DocumentChanges
+	for uri, e := range edits {
+		fh, err := snapshot.GetFile(ctx, uri)
+		if err != nil {
+			return nil, err
+		}
+		docChanges = append(docChanges, documentChanges(fh, e)...)
+	}
+	if isPkgRenaming {
+		// Update the last component of the file's enclosing directory.
+		oldBase := filepath.Dir(fh.URI().Filename())
+		newURI := filepath.Join(filepath.Dir(oldBase), params.NewName)
+		docChanges = append(docChanges, protocol.DocumentChanges{
+			RenameFile: &protocol.RenameFile{
+				Kind:   "rename",
+				OldURI: protocol.URIFromPath(oldBase),
+				NewURI: protocol.URIFromPath(newURI),
+			},
+		})
+	}
+	return &protocol.WorkspaceEdit{
+		DocumentChanges: docChanges,
+	}, nil
+}
+
+// prepareRename implements the textDocument/prepareRename handler. It may
+// return (nil, nil) if there is no rename at the cursor position, but it is
+// not desirable to display an error to the user.
+//
+// TODO(rfindley): why wouldn't we want to show an error to the user, if the
+// user initiated a rename request at the cursor?
+func (s *Server) prepareRename(ctx context.Context, params *protocol.PrepareRenameParams) (*protocol.PrepareRename2Gn, error) {
+	snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.Go)
+	defer release()
+	if !ok {
+		return nil, err
+	}
+	// Do not return errors here, as it adds clutter.
+	// Returning a nil result means there is not a valid rename.
+	item, usererr, err := source.PrepareRename(ctx, snapshot, fh, params.Position)
+	if err != nil {
+		// Return usererr here rather than err, to avoid cluttering the UI with
+		// internal error details.
+		return nil, usererr
+	}
+	return &protocol.PrepareRename2Gn{
+		Range:       item.Range,
+		Placeholder: item.Text,
+	}, nil
+}