blob: c0ed972d89fc7c46d1ab1f29b9753c138a9a0c1b [file] [log] [blame]
// Copyright 2020 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"
"go/types"
"log"
"sort"
"strings"
"time"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/lsp/template"
errors "golang.org/x/xerrors"
)
// The LSP says that errors for the semantic token requests should only be returned
// for exceptions (a word not otherwise defined). This code treats a too-large file
// as an exception. On parse errors, the code does what it can.
// reject full semantic token requests for large files
const maxFullFileSize int = 100000
func (s *Server) semanticTokensFull(ctx context.Context, p *protocol.SemanticTokensParams) (*protocol.SemanticTokens, error) {
ret, err := s.computeSemanticTokens(ctx, p.TextDocument, nil)
return ret, err
}
func (s *Server) semanticTokensFullDelta(ctx context.Context, p *protocol.SemanticTokensDeltaParams) (interface{}, error) {
return nil, errors.Errorf("implement SemanticTokensFullDelta")
}
func (s *Server) semanticTokensRange(ctx context.Context, p *protocol.SemanticTokensRangeParams) (*protocol.SemanticTokens, error) {
ret, err := s.computeSemanticTokens(ctx, p.TextDocument, &p.Range)
return ret, err
}
func (s *Server) semanticTokensRefresh(ctx context.Context) error {
// in the code, but not in the protocol spec
return errors.Errorf("implement SemanticTokensRefresh")
}
func (s *Server) computeSemanticTokens(ctx context.Context, td protocol.TextDocumentIdentifier, rng *protocol.Range) (*protocol.SemanticTokens, error) {
ans := protocol.SemanticTokens{
Data: []uint32{},
}
snapshot, fh, ok, release, err := s.beginFileRequest(ctx, td.URI, source.UnknownKind)
defer release()
if !ok {
return nil, err
}
vv := snapshot.View()
if !vv.Options().SemanticTokens {
// return an error, so if the option changes
// the client won't remember the wrong answer
return nil, errors.Errorf("semantictokens are disabled")
}
if fh.Kind() == source.Tmpl {
// this is a little cumbersome to avoid both exporting 'encoded' and its methods
// and to avoid import cycles
e := &encoded{
ctx: ctx,
rng: rng,
tokTypes: s.session.Options().SemanticTypes,
tokMods: s.session.Options().SemanticMods,
}
add := func(line, start uint32, len uint32) {
e.add(line, start, len, tokMacro, nil)
}
data := func() []uint32 {
return e.Data()
}
return template.SemanticTokens(ctx, snapshot, fh.URI(), add, data)
}
if fh.Kind() != source.Go {
return nil, nil
}
pkg, err := snapshot.PackageForFile(ctx, fh.URI(), source.TypecheckFull, source.WidestPackage)
if err != nil {
return nil, err
}
info := pkg.GetTypesInfo()
pgf, err := pkg.File(fh.URI())
if err != nil {
return nil, err
}
// don't return errors on pgf.ParseErr. Do what we can.
if rng == nil && len(pgf.Src) > maxFullFileSize {
err := fmt.Errorf("semantic tokens: file %s too large for full (%d>%d)",
fh.URI().Filename(), len(pgf.Src), maxFullFileSize)
return nil, err
}
e := &encoded{
ctx: ctx,
pgf: pgf,
rng: rng,
ti: info,
fset: snapshot.FileSet(),
tokTypes: s.session.Options().SemanticTypes,
tokMods: s.session.Options().SemanticMods,
}
if err := e.init(); err != nil {
// e.init should never return an error, unless there's some
// seemingly impossible race condition
return nil, err
}
e.semantics()
ans.Data = e.Data()
// For delta requests, but we've never seen any.
ans.ResultID = fmt.Sprintf("%v", time.Now())
return &ans, nil
}
func (e *encoded) semantics() {
f := e.pgf.File
e.token(f.Package, len("package"), tokKeyword, nil)
e.token(f.Name.NamePos, len(f.Name.Name), tokNamespace, nil)
inspect := func(n ast.Node) bool {
return e.inspector(n)
}
for _, d := range f.Decls {
// only look at the decls that overlap the range
start, end := d.Pos(), d.End()
if end <= e.start || start >= e.end {
continue
}
ast.Inspect(d, inspect)
}
for _, cg := range f.Comments {
for _, c := range cg.List {
if !strings.Contains(c.Text, "\n") {
e.token(c.Pos(), len(c.Text), tokComment, nil)
continue
}
e.multiline(c.Pos(), c.End(), c.Text, tokComment)
}
}
}
type tokenType string
const (
tokNamespace tokenType = "namespace"
tokType tokenType = "type"
tokInterface tokenType = "interface"
tokParameter tokenType = "parameter"
tokVariable tokenType = "variable"
tokMember tokenType = "member"
tokFunction tokenType = "function"
tokKeyword tokenType = "keyword"
tokComment tokenType = "comment"
tokString tokenType = "string"
tokNumber tokenType = "number"
tokOperator tokenType = "operator"
tokMacro tokenType = "macro" // for templates
)
func (e *encoded) token(start token.Pos, leng int, typ tokenType, mods []string) {
if start == 0 {
e.unexpected("token at token.NoPos")
}
if start >= e.end || start+token.Pos(leng) <= e.start {
return
}
// want a line and column from start (in LSP coordinates)
// [//line directives should be ignored]
rng := source.NewMappedRange(e.fset, e.pgf.Mapper, start, start+token.Pos(leng))
lspRange, err := rng.Range()
if err != nil {
// possibly a //line directive. TODO(pjw): fix this somehow
// "column mapper is for file...instead of..."
// "line is beyond end of file..."
// see line 116 of internal/span/token.go which uses Position not PositionFor
// (it is too verbose to print the error on every token. some other RPC will fail)
// event.Error(e.ctx, "failed to convert to range", err)
return
}
if lspRange.End.Line != lspRange.Start.Line {
// abrupt end of file, without \n. TODO(pjw): fix?
pos := e.fset.PositionFor(start, false)
msg := fmt.Sprintf("token at %s:%d.%d overflows", pos.Filename, pos.Line, pos.Column)
event.Log(e.ctx, msg)
return
}
// token is all on one line
length := lspRange.End.Character - lspRange.Start.Character
e.add(lspRange.Start.Line, lspRange.Start.Character, length, typ, mods)
}
func (e *encoded) add(line, start uint32, len uint32, tok tokenType, mod []string) {
x := semItem{line, start, len, tok, mod}
e.items = append(e.items, x)
}
// semItem represents a token found walking the parse tree
type semItem struct {
line, start uint32
len uint32
typeStr tokenType
mods []string
}
type encoded struct {
// the generated data
items []semItem
ctx context.Context
tokTypes, tokMods []string
pgf *source.ParsedGoFile
rng *protocol.Range
ti *types.Info
fset *token.FileSet
// allowed starting and ending token.Pos, set by init
// used to avoid looking at declarations not in range
start, end token.Pos
// path from the root of the parse tree, used for debugging
stack []ast.Node
}
// convert the stack to a string, for debugging
func (e *encoded) strStack() string {
msg := []string{"["}
for _, s := range e.stack {
msg = append(msg, fmt.Sprintf("%T", s)[5:])
}
if len(e.stack) > 0 {
loc := e.stack[len(e.stack)-1].Pos()
add := e.pgf.Tok.PositionFor(loc, false)
msg = append(msg, fmt.Sprintf("(line:%d,col:%d)", add.Line, add.Column))
}
msg = append(msg, "]")
return strings.Join(msg, " ")
}
func (e *encoded) inspector(n ast.Node) bool {
pop := func() {
e.stack = e.stack[:len(e.stack)-1]
}
if n == nil {
pop()
return true
}
e.stack = append(e.stack, n)
switch x := n.(type) {
case *ast.ArrayType:
case *ast.AssignStmt:
e.token(x.TokPos, len(x.Tok.String()), tokOperator, nil)
case *ast.BasicLit:
if strings.Contains(x.Value, "\n") {
// has to be a string
e.multiline(x.Pos(), x.End(), x.Value, tokString)
break
}
ln := len(x.Value)
what := tokNumber
if x.Kind == token.STRING {
what = tokString
if _, ok := e.stack[len(e.stack)-2].(*ast.Field); ok {
// struct tags (this is probably pointless, as the
// TextMate grammar will treat all the other comments the same)
what = tokComment
}
}
e.token(x.Pos(), ln, what, nil)
case *ast.BinaryExpr:
e.token(x.OpPos, len(x.Op.String()), tokOperator, nil)
case *ast.BlockStmt:
case *ast.BranchStmt:
e.token(x.TokPos, len(x.Tok.String()), tokKeyword, nil)
// There's no semantic encoding for labels
case *ast.CallExpr:
if x.Ellipsis != token.NoPos {
e.token(x.Ellipsis, len("..."), tokOperator, nil)
}
case *ast.CaseClause:
iam := "case"
if x.List == nil {
iam = "default"
}
e.token(x.Case, len(iam), tokKeyword, nil)
case *ast.ChanType:
// chan | chan <- | <- chan
if x.Arrow == token.NoPos || x.Arrow != x.Begin {
e.token(x.Begin, len("chan"), tokKeyword, nil)
break
}
pos := e.findKeyword("chan", x.Begin+2, x.Value.Pos())
e.token(pos, len("chan"), tokKeyword, nil)
case *ast.CommClause:
iam := len("case")
if x.Comm == nil {
iam = len("default")
}
e.token(x.Case, iam, tokKeyword, nil)
case *ast.CompositeLit:
case *ast.DeclStmt:
case *ast.DeferStmt:
e.token(x.Defer, len("defer"), tokKeyword, nil)
case *ast.Ellipsis:
e.token(x.Ellipsis, len("..."), tokOperator, nil)
case *ast.EmptyStmt:
case *ast.ExprStmt:
case *ast.Field:
case *ast.FieldList:
case *ast.ForStmt:
e.token(x.For, len("for"), tokKeyword, nil)
case *ast.FuncDecl:
case *ast.FuncLit:
case *ast.FuncType:
if x.Func != token.NoPos {
e.token(x.Func, len("func"), tokKeyword, nil)
}
case *ast.GenDecl:
e.token(x.TokPos, len(x.Tok.String()), tokKeyword, nil)
case *ast.GoStmt:
e.token(x.Go, len("go"), tokKeyword, nil)
case *ast.Ident:
e.ident(x)
case *ast.IfStmt:
e.token(x.If, len("if"), tokKeyword, nil)
if x.Else != nil {
// x.Body.End() or x.Body.End()+1, not that it matters
pos := e.findKeyword("else", x.Body.End(), x.Else.Pos())
e.token(pos, len("else"), tokKeyword, nil)
}
case *ast.ImportSpec:
e.importSpec(x)
pop()
return false
case *ast.IncDecStmt:
e.token(x.TokPos, len(x.Tok.String()), tokOperator, nil)
case *ast.IndexExpr:
case *ast.InterfaceType:
e.token(x.Interface, len("interface"), tokKeyword, nil)
case *ast.KeyValueExpr:
case *ast.LabeledStmt:
case *ast.MapType:
e.token(x.Map, len("map"), tokKeyword, nil)
case *ast.ParenExpr:
case *ast.RangeStmt:
e.token(x.For, len("for"), tokKeyword, nil)
// x.TokPos == token.NoPos is legal (for range foo {})
offset := x.TokPos
if offset == token.NoPos {
offset = x.For
}
pos := e.findKeyword("range", offset, x.X.Pos())
e.token(pos, len("range"), tokKeyword, nil)
case *ast.ReturnStmt:
e.token(x.Return, len("return"), tokKeyword, nil)
case *ast.SelectStmt:
e.token(x.Select, len("select"), tokKeyword, nil)
case *ast.SelectorExpr:
case *ast.SendStmt:
e.token(x.Arrow, len("<-"), tokOperator, nil)
case *ast.SliceExpr:
case *ast.StarExpr:
e.token(x.Star, len("*"), tokOperator, nil)
case *ast.StructType:
e.token(x.Struct, len("struct"), tokKeyword, nil)
case *ast.SwitchStmt:
e.token(x.Switch, len("switch"), tokKeyword, nil)
case *ast.TypeAssertExpr:
if x.Type == nil {
pos := e.findKeyword("type", x.Lparen, x.Rparen)
e.token(pos, len("type"), tokKeyword, nil)
}
case *ast.TypeSpec:
case *ast.TypeSwitchStmt:
e.token(x.Switch, len("switch"), tokKeyword, nil)
case *ast.UnaryExpr:
e.token(x.OpPos, len(x.Op.String()), tokOperator, nil)
case *ast.ValueSpec:
// things we only see with parsing or type errors, so we ignore them
case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
return true
// not going to see these
case *ast.File, *ast.Package:
log.Printf("implement %T %s", x, e.pgf.Tok.PositionFor(x.Pos(), false))
// other things we knowingly ignore
case *ast.Comment, *ast.CommentGroup:
pop()
return false
default: // just to be super safe.
e.unexpected(fmt.Sprintf("failed to implement %T", x))
}
return true
}
func (e *encoded) ident(x *ast.Ident) {
def := e.ti.Defs[x]
if def != nil {
what, mods := e.definitionFor(x)
if what != "" {
e.token(x.Pos(), len(x.String()), what, mods)
}
return
}
use := e.ti.Uses[x]
switch y := use.(type) {
case nil:
e.token(x.NamePos, len(x.Name), tokVariable, []string{"definition"})
case *types.Builtin:
e.token(x.NamePos, len(x.Name), tokFunction, []string{"defaultLibrary"})
case *types.Const:
mods := []string{"readonly"}
tt := y.Type()
if _, ok := tt.(*types.Basic); ok {
e.token(x.Pos(), len(x.String()), tokVariable, mods)
break
}
if ttx, ok := tt.(*types.Named); ok {
if x.String() == "iota" {
e.unexpected(fmt.Sprintf("iota:%T", ttx))
}
if _, ok := ttx.Underlying().(*types.Basic); ok {
e.token(x.Pos(), len(x.String()), tokVariable, mods)
break
}
e.unexpected(fmt.Sprintf("%q/%T", x.String(), tt))
}
// can this happen? Don't think so
e.unexpected(fmt.Sprintf("%s %T %#v", x.String(), tt, tt))
case *types.Func:
e.token(x.Pos(), len(x.Name), tokFunction, nil)
case *types.Label:
// nothing to map it to
case *types.Nil:
// nil is a predeclared identifier
e.token(x.Pos(), len("nil"), tokVariable, []string{"readonly", "defaultLibrary"})
case *types.PkgName:
e.token(x.Pos(), len(x.Name), tokNamespace, nil)
case *types.TypeName:
var mods []string
if _, ok := y.Type().(*types.Basic); ok {
mods = []string{"defaultLibrary"}
}
e.token(x.Pos(), len(x.String()), tokType, mods)
case *types.Var:
e.token(x.Pos(), len(x.Name), tokVariable, nil)
default:
// can't happen
if use == nil {
msg := fmt.Sprintf("%#v/%#v %#v %#v", x, x.Obj, e.ti.Defs[x], e.ti.Uses[x])
e.unexpected(msg)
}
if use.Type() != nil {
e.unexpected(fmt.Sprintf("%s %T/%T,%#v", x.String(), use, use.Type(), use))
} else {
e.unexpected(fmt.Sprintf("%s %T", x.String(), use))
}
}
}
func isDeprecated(n *ast.CommentGroup) bool {
if n == nil {
return false
}
for _, c := range n.List {
if strings.HasPrefix(c.Text, "// Deprecated") {
return true
}
}
return false
}
func (e *encoded) definitionFor(x *ast.Ident) (tokenType, []string) {
mods := []string{"definition"}
for i := len(e.stack) - 1; i >= 0; i-- {
s := e.stack[i]
switch y := s.(type) {
case *ast.AssignStmt, *ast.RangeStmt:
if x.Name == "_" {
return "", nil // not really a variable
}
return "variable", mods
case *ast.GenDecl:
if isDeprecated(y.Doc) {
mods = append(mods, "deprecated")
}
if y.Tok == token.CONST {
mods = append(mods, "readonly")
}
return tokVariable, mods
case *ast.FuncDecl:
// If x is immediately under a FuncDecl, it is a function or method
if i == len(e.stack)-2 {
if isDeprecated(y.Doc) {
mods = append(mods, "deprecated")
}
if y.Recv != nil {
return tokMember, mods
}
return tokFunction, mods
}
// if x < ... < FieldList < FuncDecl, this is the receiver, a variable
if _, ok := e.stack[i+1].(*ast.FieldList); ok {
return tokVariable, nil
}
// if x < ... < FieldList < FuncType < FuncDecl, this is a param
return tokParameter, mods
case *ast.InterfaceType:
return tokMember, mods
case *ast.TypeSpec:
// GenDecl/Typespec/FuncType/FieldList/Field/Ident
// (type A func(b uint64)) (err error)
// b and err should not be tokType, but tokVaraible
// and in GenDecl/TpeSpec/StructType/FieldList/Field/Ident
// (type A struct{b uint64}
// but on type B struct{C}), C is a type, but is not being defined.
fldm := e.stack[len(e.stack)-2]
if fld, ok := fldm.(*ast.Field); ok {
// if len(fld.names) == 0 this is a tokType, being used
if len(fld.Names) == 0 {
return tokType, nil
}
return tokVariable, mods
}
return tokType, mods
}
}
// can't happen
msg := fmt.Sprintf("failed to find the decl for %s", e.pgf.Tok.PositionFor(x.Pos(), false))
e.unexpected(msg)
return "", []string{""}
}
func (e *encoded) multiline(start, end token.Pos, val string, tok tokenType) {
f := e.fset.File(start)
// the hard part is finding the lengths of lines. include the \n
leng := func(line int) int {
n := f.LineStart(line)
if line >= f.LineCount() {
return f.Size() - int(n)
}
return int(f.LineStart(line+1) - n)
}
spos := e.fset.PositionFor(start, false)
epos := e.fset.PositionFor(end, false)
sline := spos.Line
eline := epos.Line
// first line is from spos.Column to end
e.token(start, leng(sline)-spos.Column, tok, nil) // leng(sline)-1 - (spos.Column-1)
for i := sline + 1; i < eline; i++ {
// intermediate lines are from 1 to end
e.token(f.LineStart(i), leng(i)-1, tok, nil) // avoid the newline
}
// last line is from 1 to epos.Column
e.token(f.LineStart(eline), epos.Column-1, tok, nil) // columns are 1-based
}
// findKeyword finds a keyword rather than guessing its location
func (e *encoded) findKeyword(keyword string, start, end token.Pos) token.Pos {
offset := int(start) - e.pgf.Tok.Base()
last := int(end) - e.pgf.Tok.Base()
buf := e.pgf.Src
idx := bytes.Index(buf[offset:last], []byte(keyword))
if idx != -1 {
return start + token.Pos(idx)
}
// can't happen
e.unexpected(fmt.Sprintf("not found:%s %v", keyword, e.fset.PositionFor(start, false)))
return token.NoPos
}
func (e *encoded) init() error {
e.start = token.Pos(e.pgf.Tok.Base())
e.end = e.start + token.Pos(e.pgf.Tok.Size())
if e.rng == nil {
return nil
}
span, err := e.pgf.Mapper.RangeSpan(*e.rng)
if err != nil {
return errors.Errorf("range span (%w) error for %s", err, e.pgf.File.Name)
}
e.end = e.start + token.Pos(span.End().Offset())
e.start += token.Pos(span.Start().Offset())
return nil
}
func (e *encoded) Data() []uint32 {
// binary operators, at least, will be out of order
sort.Slice(e.items, func(i, j int) bool {
if e.items[i].line != e.items[j].line {
return e.items[i].line < e.items[j].line
}
return e.items[i].start < e.items[j].start
})
typeMap, modMap := e.maps()
// each semantic token needs five values
// (see Integer Encoding for Tokens in the LSP spec)
x := make([]uint32, 5*len(e.items))
for i := 0; i < len(e.items); i++ {
j := 5 * i
if i == 0 {
x[0] = e.items[0].line
} else {
x[j] = e.items[i].line - e.items[i-1].line
}
x[j+1] = e.items[i].start
if i > 0 && e.items[i].line == e.items[i-1].line {
x[j+1] = e.items[i].start - e.items[i-1].start
}
x[j+2] = e.items[i].len
typ, ok := typeMap[e.items[i].typeStr]
if !ok {
continue // client doesn't want typeStr
}
x[j+3] = uint32(typ)
mask := 0
for _, s := range e.items[i].mods {
// modMpa[s] is 0 if the client doesn't want this modifier
mask |= modMap[s]
}
x[j+4] = uint32(mask)
}
return x
}
func (e *encoded) importSpec(d *ast.ImportSpec) {
// a local package name or the last component of the Path
if d.Name != nil {
nm := d.Name.String()
// import . x => x is not a namespace
// import _ x => x is a namespace
if nm != "_" && nm != "." {
e.token(d.Name.Pos(), len(nm), tokNamespace, nil)
return
}
if nm == "." {
return
}
// and fall through for _
}
if d.Path.Value == "" {
return
}
nm := d.Path.Value[1 : len(d.Path.Value)-1] // trailing "
v := strings.LastIndex(nm, "/")
if v != -1 {
nm = nm[v+1:]
}
start := d.Path.End() - token.Pos(1+len(nm))
e.token(start, len(nm), tokNamespace, nil)
}
// log unexpected state
func (e *encoded) unexpected(msg string) {
event.Error(e.ctx, e.strStack(), errors.New(msg))
}
// SemType returns a string equivalent of the type, for gopls semtok
func SemType(n int) string {
tokTypes := SemanticTypes()
tokMods := SemanticModifiers()
if n >= 0 && n < len(tokTypes) {
return tokTypes[n]
}
return fmt.Sprintf("?%d[%d,%d]?", n, len(tokTypes), len(tokMods))
}
// SemMods returns the []string equivalent of the mods, for gopls semtok.
func SemMods(n int) []string {
tokMods := SemanticModifiers()
mods := []string{}
for i := 0; i < len(tokMods); i++ {
if (n & (1 << uint(i))) != 0 {
mods = append(mods, tokMods[i])
}
}
return mods
}
func (e *encoded) maps() (map[tokenType]int, map[string]int) {
tmap := make(map[tokenType]int)
mmap := make(map[string]int)
for i, t := range e.tokTypes {
tmap[tokenType(t)] = i
}
for i, m := range e.tokMods {
mmap[m] = 1 << uint(i) // go 1.12 compatibility
}
return tmap, mmap
}
// SemanticTypes to use in case there is no client, as in the command line, or tests
func SemanticTypes() []string {
return semanticTypes[:]
}
// SemanticModifiers to use in case there is no client.
func SemanticModifiers() []string {
return semanticModifiers[:]
}
var (
semanticTypes = [...]string{
"namespace", "type", "class", "enum", "interface",
"struct", "typeParameter", "parameter", "variable", "property", "enumMember",
"event", "function", "member", "macro", "keyword", "modifier", "comment",
"string", "number", "regexp", "operator",
}
semanticModifiers = [...]string{
"declaration", "definition", "readonly", "static",
"deprecated", "abstract", "async", "modification", "documentation", "defaultLibrary",
}
)