tools/gopls: add cmd support for folding_ranges

This change adds command line support for foldingRange.
Provided with a file, it will display a list of folding
ranges within that file, with 1-indexed positions using
the format
{startingLine}:{startingChar}-{endingLine}:{endingChar}

Example:

$ gopls folding_ranges ~/tmp/foo/main.go
$
$ 3:9-6:0
$ 10:22-11:32
$ 12:10-12:9
$ 12:20-30:0

Updates golang/go#32875

Change-Id: Ib35cf26088736e7c35612d783c80be7ae41b6a70
Reviewed-on: https://go-review.googlesource.com/c/tools/+/206158
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/cmd/cmd.go

@@ -142,6 +142,7 @@ func (app *Application) commands() []tool.Application {
 		&app.Serve,
 		&bug{},
 		&check{app: app},
+		&foldingRanges{app: app},
 		&format{app: app},
 		&links{app: app},
 		&imports{app: app},

internal/lsp/cmd/folding_range.go

@@ -0,0 +1,72 @@
+// 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 cmd
+
+import (
+	"context"
+	"flag"
+	"fmt"
+
+	"golang.org/x/tools/internal/lsp/protocol"
+	"golang.org/x/tools/internal/span"
+	"golang.org/x/tools/internal/tool"
+)
+
+// foldingRanges implements the folding_ranges verb for gopls
+type foldingRanges struct {
+	app *Application
+}
+
+func (r *foldingRanges) Name() string      { return "folding_ranges" }
+func (r *foldingRanges) Usage() string     { return "<file>" }
+func (r *foldingRanges) ShortHelp() string { return "display selected file's folding ranges" }
+func (r *foldingRanges) DetailedHelp(f *flag.FlagSet) {
+	fmt.Fprint(f.Output(), `
+Example:
+
+  $ gopls folding_ranges helper/helper.go
+`)
+	f.PrintDefaults()
+}
+
+func (r *foldingRanges) Run(ctx context.Context, args ...string) error {
+	if len(args) != 1 {
+		return tool.CommandLineErrorf("folding_ranges expects 1 argument (file)")
+	}
+
+	conn, err := r.app.connect(ctx)
+	if err != nil {
+		return err
+	}
+	defer conn.terminate(ctx)
+
+	from := span.Parse(args[0])
+	file := conn.AddFile(ctx, from.URI())
+	if file.err != nil {
+		return file.err
+	}
+
+	p := protocol.FoldingRangeParams{
+		TextDocument: protocol.TextDocumentIdentifier{
+			URI: protocol.NewURI(from.URI()),
+		},
+	}
+
+	ranges, err := conn.FoldingRange(ctx, &p)
+	if err != nil {
+		return err
+	}
+
+	for _, r := range ranges {
+		fmt.Printf("%v:%v-%v:%v\n",
+			r.StartLine+1,
+			r.StartCharacter+1,
+			r.EndLine+1,
+			r.EndCharacter,
+		)
+	}
+
+	return nil
+}

internal/lsp/cmd/test/cmdtest.go

@@ -65,10 +65,6 @@ func (r *runner) RankCompletion(t *testing.T, src span.Span, test tests.Completi
 	//TODO: add command line completions tests when it works
 }
 
-func (r *runner) FoldingRange(t *testing.T, spn span.Span) {
-	//TODO: add command line folding range tests when it works
-}
-
 func (r *runner) Highlight(t *testing.T, name string, locations []span.Span) {
 	//TODO: add command line highlight tests when it works
 }

internal/lsp/cmd/test/folding_range.go

@@ -0,0 +1,32 @@
+package cmdtest
+
+import (
+	"fmt"
+	"testing"
+
+	"golang.org/x/tools/internal/lsp/cmd"
+	"golang.org/x/tools/internal/span"
+	"golang.org/x/tools/internal/tool"
+)
+
+func (r *runner) FoldingRanges(t *testing.T, spn span.Span) {
+	goldenTag := "foldingRange-cmd"
+	uri := spn.URI()
+	filename := uri.Filename()
+
+	app := cmd.New("gopls-test", r.data.Config.Dir, r.data.Config.Env, r.options)
+	got := CaptureStdOut(t, func() {
+		err := tool.Run(r.ctx, app, append([]string{"-remote=internal", "folding_ranges"}, filename))
+		if err != nil {
+			fmt.Println(err)
+		}
+	})
+
+	expect := string(r.data.Golden(goldenTag, filename, func() ([]byte, error) {
+		return []byte(got), nil
+	}))
+
+	if expect != got {
+		t.Errorf("folding_ranges failed failed for %s expected:\n%s\ngot:\n%s", filename, expect, got)
+	}
+}

internal/lsp/lsp_test.go

@@ -96,7 +96,7 @@ func (r *runner) Diagnostics(t *testing.T, uri span.URI, want []source.Diagnosti
 	}
 }
 
-func (r *runner) FoldingRange(t *testing.T, spn span.Span) {
+func (r *runner) FoldingRanges(t *testing.T, spn span.Span) {
 	uri := spn.URI()
 	view := r.server.session.ViewOf(uri)
 	original := view.Options()

internal/lsp/source/source_test.go

@@ -273,7 +273,7 @@ func (r *runner) callCompletion(t *testing.T, src span.Span, options source.Comp
 	return prefix, tests.ToProtocolCompletionItems(items)
 }
 
-func (r *runner) FoldingRange(t *testing.T, spn span.Span) {
+func (r *runner) FoldingRanges(t *testing.T, spn span.Span) {
 	uri := spn.URI()
 
 	f, err := r.view.GetFile(r.ctx, uri)

internal/lsp/testdata/folding/a.go.golden

@@ -113,6 +113,23 @@ this string
 is not indented`
 }
 
+-- foldingRange-cmd --
+3:9-6:0
+10:22-11:32
+12:10-12:9
+12:20-30:0
+13:10-24:1
+14:12-19:3
+15:12-17:2
+16:16-16:21
+17:11-19:2
+18:16-18:22
+20:13-21:22
+21:15-21:21
+22:10-23:24
+23:15-23:23
+25:32-26:30
+
 -- foldingRange-comment-0 --
 package folding //@fold("package")
 

internal/lsp/testdata/folding/bad.go.golden

@@ -44,6 +44,16 @@ func badBar() string { x := true
 	return
 }
 
+-- foldingRange-cmd --
+3:9-5:0
+7:9-8:8
+11:13-11:12
+11:23-18:0
+12:8-15:1
+14:15-14:20
+15:10-16:23
+16:15-16:21
+
 -- foldingRange-imports-0 --
 package folding //@fold("package")
 

internal/lsp/tests/tests.go

@@ -107,7 +107,7 @@ type Tests interface {
 	FuzzyCompletion(*testing.T, span.Span, Completion, CompletionItems)
 	CaseSensitiveCompletion(*testing.T, span.Span, Completion, CompletionItems)
 	RankCompletion(*testing.T, span.Span, Completion, CompletionItems)
-	FoldingRange(*testing.T, span.Span)
+	FoldingRanges(*testing.T, span.Span)
 	Format(*testing.T, span.Span)
 	Import(*testing.T, span.Span)
 	SuggestedFix(*testing.T, span.Span)
@@ -422,7 +422,7 @@ func Run(t *testing.T, tests Tests, data *Data) {
 		for _, spn := range data.FoldingRanges {
 			t.Run(uriName(spn.URI()), func(t *testing.T) {
 				t.Helper()
-				tests.FoldingRange(t, spn)
+				tests.FoldingRanges(t, spn)
 			})
 		}
 	})