internal/lsp/link.go - tools - Git at Google

 // 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 lsp

 import (
 	"bytes"
 	"context"
 	"fmt"
 	"go/ast"
 	"go/token"
 	"net/url"
 	"regexp"
 	"strconv"
 	"strings"
 	"sync"

 	"golang.org/x/mod/modfile"
 	"golang.org/x/tools/internal/event"
 	"golang.org/x/tools/internal/lsp/debug/tag"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/span"
 )

 func (s *Server) documentLink(ctx context.Context, params *protocol.DocumentLinkParams) (links []protocol.DocumentLink, err error) {
 	snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.UnknownKind)
 	defer release()
 	if !ok {
 		return nil, err
 	}
 	switch fh.Kind() {
 	case source.Mod:
 		links, err = modLinks(ctx, snapshot, fh)
 	case source.Go:
 		links, err = goLinks(ctx, snapshot, fh)
 	}
 	// Don't return errors for document links.
 	if err != nil {
 		event.Error(ctx, "failed to compute document links", err, tag.URI.Of(fh.URI()))
 		return nil, nil
 	}
 	return links, nil
 }

 func modLinks(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle) ([]protocol.DocumentLink, error) {
 	pm, err := snapshot.ParseMod(ctx, fh)
 	if err != nil {
 		return nil, err
 	}
 	var links []protocol.DocumentLink
 	for _, req := range pm.File.Require {
 		if req.Syntax == nil {
 			continue
 		}
 		// See golang/go#36998: don't link to modules matching GOPRIVATE.
 		if snapshot.View().IsGoPrivatePath(req.Mod.Path) {
 			continue
 		}
 		dep := []byte(req.Mod.Path)
 		s, e := req.Syntax.Start.Byte, req.Syntax.End.Byte
 		i := bytes.Index(pm.Mapper.Content[s:e], dep)
 		if i == -1 {
 			continue
 		}
 		// Shift the start position to the location of the
 		// dependency within the require statement.
 		start, end := token.Pos(s+i), token.Pos(s+i+len(dep))
 		target := source.BuildLink(snapshot.View().Options().LinkTarget, "mod/"+req.Mod.String(), "")
 		l, err := toProtocolLink(snapshot, pm.Mapper, target, start, end, source.Mod)
 		if err != nil {
 			return nil, err
 		}
 		links = append(links, l)
 	}
 	// TODO(ridersofrohan): handle links for replace and exclude directives.
 	if syntax := pm.File.Syntax; syntax == nil {
 		return links, nil
 	}
 	// Get all the links that are contained in the comments of the file.
 	for _, expr := range pm.File.Syntax.Stmt {
 		comments := expr.Comment()
 		if comments == nil {
 			continue
 		}
 		for _, section := range [][]modfile.Comment{comments.Before, comments.Suffix, comments.After} {
 			for _, comment := range section {
 				l, err := findLinksInString(ctx, snapshot, comment.Token, token.Pos(comment.Start.Byte), pm.Mapper, source.Mod)
 				if err != nil {
 					return nil, err
 				}
 				links = append(links, l...)
 			}
 		}
 	}
 	return links, nil
 }

 func goLinks(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle) ([]protocol.DocumentLink, error) {
 	view := snapshot.View()
 	// We don't actually need type information, so any typecheck mode is fine.
 	pkg, err := snapshot.PackageForFile(ctx, fh.URI(), source.TypecheckWorkspace, source.WidestPackage)
 	if err != nil {
 		return nil, err
 	}
 	pgf, err := snapshot.ParseGo(ctx, fh, source.ParseFull)
 	if err != nil {
 		return nil, err
 	}
 	var imports []*ast.ImportSpec
 	var str []*ast.BasicLit
 	ast.Inspect(pgf.File, func(node ast.Node) bool {
 		switch n := node.(type) {
 		case *ast.ImportSpec:
 			imports = append(imports, n)
 			return false
 		case *ast.BasicLit:
 			// Look for links in string literals.
 			if n.Kind == token.STRING {
 				str = append(str, n)
 			}
 			return false
 		}
 		return true
 	})
 	var links []protocol.DocumentLink
 	// For import specs, provide a link to a documentation website, like
 	// https://pkg.go.dev.
 	if view.Options().ImportShortcut.ShowLinks() {
 		for _, imp := range imports {
 			target, err := strconv.Unquote(imp.Path.Value)
 			if err != nil {
 				continue
 			}
 			// See golang/go#36998: don't link to modules matching GOPRIVATE.
 			if view.IsGoPrivatePath(target) {
 				continue
 			}
 			if mod, version, ok := moduleAtVersion(ctx, snapshot, target, pkg); ok && strings.ToLower(view.Options().LinkTarget) == "pkg.go.dev" {
 				target = strings.Replace(target, mod, mod+"@"+version, 1)
 			}
 			// Account for the quotation marks in the positions.
 			start := imp.Path.Pos() + 1
 			end := imp.Path.End() - 1
 			target = source.BuildLink(view.Options().LinkTarget, target, "")
 			l, err := toProtocolLink(snapshot, pgf.Mapper, target, start, end, source.Go)
 			if err != nil {
 				return nil, err
 			}
 			links = append(links, l)
 		}
 	}
 	for _, s := range str {
 		l, err := findLinksInString(ctx, snapshot, s.Value, s.Pos(), pgf.Mapper, source.Go)
 		if err != nil {
 			return nil, err
 		}
 		links = append(links, l...)
 	}
 	for _, commentGroup := range pgf.File.Comments {
 		for _, comment := range commentGroup.List {
 			l, err := findLinksInString(ctx, snapshot, comment.Text, comment.Pos(), pgf.Mapper, source.Go)
 			if err != nil {
 				return nil, err
 			}
 			links = append(links, l...)
 		}
 	}
 	return links, nil
 }

 func moduleAtVersion(ctx context.Context, snapshot source.Snapshot, target string, pkg source.Package) (string, string, bool) {
 	impPkg, err := pkg.GetImport(target)
 	if err != nil {
 		return "", "", false
 	}
 	if impPkg.Version() == nil {
 		return "", "", false
 	}
 	version, modpath := impPkg.Version().Version, impPkg.Version().Path
 	if modpath == "" || version == "" {
 		return "", "", false
 	}
 	return modpath, version, true
 }

 func findLinksInString(ctx context.Context, snapshot source.Snapshot, src string, pos token.Pos, m *protocol.ColumnMapper, fileKind source.FileKind) ([]protocol.DocumentLink, error) {
 	var links []protocol.DocumentLink
 	for _, index := range snapshot.View().Options().URLRegexp.FindAllIndex([]byte(src), -1) {
 		start, end := index[0], index[1]
 		startPos := token.Pos(int(pos) + start)
 		endPos := token.Pos(int(pos) + end)
 		link := src[start:end]
 		linkURL, err := url.Parse(link)
 		// Fallback: Linkify IP addresses as suggested in golang/go#18824.
 		if err != nil {
 			linkURL, err = url.Parse("//" + link)
 			// Not all potential links will be valid, so don't return this error.
 			if err != nil {
 				continue
 			}
 		}
 		// If the URL has no scheme, use https.
 		if linkURL.Scheme == "" {
 			linkURL.Scheme = "https"
 		}
 		l, err := toProtocolLink(snapshot, m, linkURL.String(), startPos, endPos, fileKind)
 		if err != nil {
 			return nil, err
 		}
 		links = append(links, l)
 	}
 	// Handle golang/go#1234-style links.
 	r := getIssueRegexp()
 	for _, index := range r.FindAllIndex([]byte(src), -1) {
 		start, end := index[0], index[1]
 		startPos := token.Pos(int(pos) + start)
 		endPos := token.Pos(int(pos) + end)
 		matches := r.FindStringSubmatch(src)
 		if len(matches) < 4 {
 			continue
 		}
 		org, repo, number := matches[1], matches[2], matches[3]
 		target := fmt.Sprintf("https://github.com/%s/%s/issues/%s", org, repo, number)
 		l, err := toProtocolLink(snapshot, m, target, startPos, endPos, fileKind)
 		if err != nil {
 			return nil, err
 		}
 		links = append(links, l)
 	}
 	return links, nil
 }

 func getIssueRegexp() *regexp.Regexp {
 	once.Do(func() {
 		issueRegexp = regexp.MustCompile(`(\w+)/([\w-]+)#([0-9]+)`)
 	})
 	return issueRegexp
 }

 var (
 	once        sync.Once
 	issueRegexp *regexp.Regexp
 )

 func toProtocolLink(snapshot source.Snapshot, m *protocol.ColumnMapper, target string, start, end token.Pos, fileKind source.FileKind) (protocol.DocumentLink, error) {
 	var rng protocol.Range
 	switch fileKind {
 	case source.Go:
 		spn, err := span.NewRange(snapshot.FileSet(), start, end).Span()
 		if err != nil {
 			return protocol.DocumentLink{}, err
 		}
 		rng, err = m.Range(spn)
 		if err != nil {
 			return protocol.DocumentLink{}, err
 		}
 	case source.Mod:
 		s, e := int(start), int(end)
 		line, col, err := m.Converter.ToPosition(s)
 		if err != nil {
 			return protocol.DocumentLink{}, err
 		}
 		start := span.NewPoint(line, col, s)
 		line, col, err = m.Converter.ToPosition(e)
 		if err != nil {
 			return protocol.DocumentLink{}, err
 		}
 		end := span.NewPoint(line, col, e)
 		rng, err = m.Range(span.New(m.URI, start, end))
 		if err != nil {
 			return protocol.DocumentLink{}, err
 		}
 	}
 	return protocol.DocumentLink{
 		Range:  rng,
 		Target: target,
 	}, nil
 }
	// 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 lsp

	import (
	"bytes"
	"context"
	"fmt"
	"go/ast"
	"go/token"
	"net/url"
	"regexp"
	"strconv"
	"strings"
	"sync"

	"golang.org/x/mod/modfile"
	"golang.org/x/tools/internal/event"
	"golang.org/x/tools/internal/lsp/debug/tag"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/span"
	)

	func (s Server) documentLink(ctx context.Context, params protocol.DocumentLinkParams) (links []protocol.DocumentLink, err error) {
	snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.UnknownKind)
	defer release()
	if !ok {
	return nil, err
	}
	switch fh.Kind() {
	case source.Mod:
	links, err = modLinks(ctx, snapshot, fh)
	case source.Go:
	links, err = goLinks(ctx, snapshot, fh)
	}
	// Don't return errors for document links.
	if err != nil {
	event.Error(ctx, "failed to compute document links", err, tag.URI.Of(fh.URI()))
	return nil, nil
	}
	return links, nil
	}

	func modLinks(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle) ([]protocol.DocumentLink, error) {
	pm, err := snapshot.ParseMod(ctx, fh)
	if err != nil {
	return nil, err
	}
	var links []protocol.DocumentLink
	for _, req := range pm.File.Require {
	if req.Syntax == nil {
	continue
	}
	// See golang/go#36998: don't link to modules matching GOPRIVATE.
	if snapshot.View().IsGoPrivatePath(req.Mod.Path) {
	continue
	}
	dep := []byte(req.Mod.Path)
	s, e := req.Syntax.Start.Byte, req.Syntax.End.Byte
	i := bytes.Index(pm.Mapper.Content[s:e], dep)
	if i == -1 {
	continue
	}
	// Shift the start position to the location of the
	// dependency within the require statement.
	start, end := token.Pos(s+i), token.Pos(s+i+len(dep))
	target := source.BuildLink(snapshot.View().Options().LinkTarget, "mod/"+req.Mod.String(), "")
	l, err := toProtocolLink(snapshot, pm.Mapper, target, start, end, source.Mod)
	if err != nil {
	return nil, err
	}
	links = append(links, l)
	}
	// TODO(ridersofrohan): handle links for replace and exclude directives.
	if syntax := pm.File.Syntax; syntax == nil {
	return links, nil
	}
	// Get all the links that are contained in the comments of the file.
	for _, expr := range pm.File.Syntax.Stmt {
	comments := expr.Comment()
	if comments == nil {
	continue
	}
	for _, section := range [][]modfile.Comment{comments.Before, comments.Suffix, comments.After} {
	for _, comment := range section {
	l, err := findLinksInString(ctx, snapshot, comment.Token, token.Pos(comment.Start.Byte), pm.Mapper, source.Mod)
	if err != nil {
	return nil, err
	}
	links = append(links, l...)
	}
	}
	}
	return links, nil
	}

	func goLinks(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle) ([]protocol.DocumentLink, error) {
	view := snapshot.View()
	// We don't actually need type information, so any typecheck mode is fine.
	pkg, err := snapshot.PackageForFile(ctx, fh.URI(), source.TypecheckWorkspace, source.WidestPackage)
	if err != nil {
	return nil, err
	}
	pgf, err := snapshot.ParseGo(ctx, fh, source.ParseFull)
	if err != nil {
	return nil, err
	}
	var imports []*ast.ImportSpec
	var str []*ast.BasicLit
	ast.Inspect(pgf.File, func(node ast.Node) bool {
	switch n := node.(type) {
	case *ast.ImportSpec:
	imports = append(imports, n)
	return false
	case *ast.BasicLit:
	// Look for links in string literals.
	if n.Kind == token.STRING {
	str = append(str, n)
	}
	return false
	}
	return true
	})
	var links []protocol.DocumentLink
	// For import specs, provide a link to a documentation website, like
	// https://pkg.go.dev.
	if view.Options().ImportShortcut.ShowLinks() {
	for _, imp := range imports {
	target, err := strconv.Unquote(imp.Path.Value)
	if err != nil {
	continue
	}
	// See golang/go#36998: don't link to modules matching GOPRIVATE.
	if view.IsGoPrivatePath(target) {
	continue
	}
	if mod, version, ok := moduleAtVersion(ctx, snapshot, target, pkg); ok && strings.ToLower(view.Options().LinkTarget) == "pkg.go.dev" {
	target = strings.Replace(target, mod, mod+"@"+version, 1)
	}
	// Account for the quotation marks in the positions.
	start := imp.Path.Pos() + 1
	end := imp.Path.End() - 1
	target = source.BuildLink(view.Options().LinkTarget, target, "")
	l, err := toProtocolLink(snapshot, pgf.Mapper, target, start, end, source.Go)
	if err != nil {
	return nil, err
	}
	links = append(links, l)
	}
	}
	for _, s := range str {
	l, err := findLinksInString(ctx, snapshot, s.Value, s.Pos(), pgf.Mapper, source.Go)
	if err != nil {
	return nil, err
	}
	links = append(links, l...)
	}
	for _, commentGroup := range pgf.File.Comments {
	for _, comment := range commentGroup.List {
	l, err := findLinksInString(ctx, snapshot, comment.Text, comment.Pos(), pgf.Mapper, source.Go)
	if err != nil {
	return nil, err
	}
	links = append(links, l...)
	}
	}
	return links, nil
	}

	func moduleAtVersion(ctx context.Context, snapshot source.Snapshot, target string, pkg source.Package) (string, string, bool) {
	impPkg, err := pkg.GetImport(target)
	if err != nil {
	return "", "", false
	}
	if impPkg.Version() == nil {
	return "", "", false
	}
	version, modpath := impPkg.Version().Version, impPkg.Version().Path
	if modpath == "" \|\| version == "" {
	return "", "", false
	}
	return modpath, version, true
	}

	func findLinksInString(ctx context.Context, snapshot source.Snapshot, src string, pos token.Pos, m *protocol.ColumnMapper, fileKind source.FileKind) ([]protocol.DocumentLink, error) {
	var links []protocol.DocumentLink
	for _, index := range snapshot.View().Options().URLRegexp.FindAllIndex([]byte(src), -1) {
	start, end := index[0], index[1]
	startPos := token.Pos(int(pos) + start)
	endPos := token.Pos(int(pos) + end)
	link := src[start:end]
	linkURL, err := url.Parse(link)
	// Fallback: Linkify IP addresses as suggested in golang/go#18824.
	if err != nil {
	linkURL, err = url.Parse("//" + link)
	// Not all potential links will be valid, so don't return this error.
	if err != nil {
	continue
	}
	}
	// If the URL has no scheme, use https.
	if linkURL.Scheme == "" {
	linkURL.Scheme = "https"
	}
	l, err := toProtocolLink(snapshot, m, linkURL.String(), startPos, endPos, fileKind)
	if err != nil {
	return nil, err
	}
	links = append(links, l)
	}
	// Handle golang/go#1234-style links.
	r := getIssueRegexp()
	for _, index := range r.FindAllIndex([]byte(src), -1) {
	start, end := index[0], index[1]
	startPos := token.Pos(int(pos) + start)
	endPos := token.Pos(int(pos) + end)
	matches := r.FindStringSubmatch(src)
	if len(matches) < 4 {
	continue
	}
	org, repo, number := matches[1], matches[2], matches[3]
	target := fmt.Sprintf("https://github.com/%s/%s/issues/%s", org, repo, number)
	l, err := toProtocolLink(snapshot, m, target, startPos, endPos, fileKind)
	if err != nil {
	return nil, err
	}
	links = append(links, l)
	}
	return links, nil
	}

	func getIssueRegexp() *regexp.Regexp {
	once.Do(func() {
	issueRegexp = regexp.MustCompile(`(\w+)/([\w-]+)#([0-9]+)`)
	})
	return issueRegexp
	}

	var (
	once sync.Once
	issueRegexp *regexp.Regexp
	)

	func toProtocolLink(snapshot source.Snapshot, m *protocol.ColumnMapper, target string, start, end token.Pos, fileKind source.FileKind) (protocol.DocumentLink, error) {
	var rng protocol.Range
	switch fileKind {
	case source.Go:
	spn, err := span.NewRange(snapshot.FileSet(), start, end).Span()
	if err != nil {
	return protocol.DocumentLink{}, err
	}
	rng, err = m.Range(spn)
	if err != nil {
	return protocol.DocumentLink{}, err
	}
	case source.Mod:
	s, e := int(start), int(end)
	line, col, err := m.Converter.ToPosition(s)
	if err != nil {
	return protocol.DocumentLink{}, err
	}
	start := span.NewPoint(line, col, s)
	line, col, err = m.Converter.ToPosition(e)
	if err != nil {
	return protocol.DocumentLink{}, err
	}
	end := span.NewPoint(line, col, e)
	rng, err = m.Range(span.New(m.URI, start, end))
	if err != nil {
	return protocol.DocumentLink{}, err
	}
	}
	return protocol.DocumentLink{
	Range: rng,
	Target: target,
	}, nil
	}