blob: 3bdb955998afd9b716b18db2340402cb6d225a15 [file] [log] [blame]
// 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 source
import (
"context"
"fmt"
"go/ast"
"go/token"
"go/types"
"path/filepath"
"regexp"
"strings"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/span"
errors "golang.org/x/xerrors"
)
type mappedRange struct {
spanRange span.Range
m *protocol.ColumnMapper
// protocolRange is the result of converting the spanRange using the mapper.
// It is computed on-demand.
protocolRange *protocol.Range
}
func (s mappedRange) Range() (protocol.Range, error) {
if s.protocolRange == nil {
spn, err := s.spanRange.Span()
if err != nil {
return protocol.Range{}, err
}
prng, err := s.m.Range(spn)
if err != nil {
return protocol.Range{}, err
}
s.protocolRange = &prng
}
return *s.protocolRange, nil
}
func (s mappedRange) Span() (span.Span, error) {
return s.spanRange.Span()
}
func (s mappedRange) URI() span.URI {
return s.m.URI
}
// bestPackage picks the "narrowest" package for a given file.
//
// By "narrowest" package, we mean the package with the fewest number of files
// that includes the given file. This solves the problem of test variants,
// as the test will have more files than the non-test package.
func bestPackage(uri span.URI, pkgs []Package) (Package, error) {
var result Package
for _, pkg := range pkgs {
if result == nil || len(pkg.GetHandles()) < len(result.GetHandles()) {
result = pkg
}
}
if result == nil {
return nil, errors.Errorf("no CheckPackageHandle for %s", uri)
}
return result, nil
}
func fileToMapper(ctx context.Context, view View, uri span.URI) (*ast.File, []Package, *protocol.ColumnMapper, error) {
f, err := view.GetFile(ctx, uri)
if err != nil {
return nil, nil, nil, err
}
gof, ok := f.(GoFile)
if !ok {
return nil, nil, nil, errors.Errorf("%s is not a Go file", f.URI())
}
pkgs, err := gof.GetPackages(ctx)
if err != nil {
return nil, nil, nil, err
}
pkg, err := bestPackage(f.URI(), pkgs)
if err != nil {
return nil, nil, nil, err
}
file, m, err := pkgToMapper(ctx, view, pkg, f.URI())
if err != nil {
return nil, nil, nil, err
}
return file, pkgs, m, nil
}
func cachedFileToMapper(ctx context.Context, view View, uri span.URI) (*ast.File, *protocol.ColumnMapper, error) {
f, err := view.GetFile(ctx, uri)
if err != nil {
return nil, nil, err
}
gof, ok := f.(GoFile)
if !ok {
return nil, nil, errors.Errorf("%s is not a Go file", f.URI())
}
if file, ok := gof.Builtin(); ok {
return builtinFileToMapper(ctx, view, gof, file)
}
pkg, err := gof.GetCachedPackage(ctx)
if err != nil {
return nil, nil, err
}
file, m, err := pkgToMapper(ctx, view, pkg, f.URI())
if err != nil {
return nil, nil, err
}
return file, m, nil
}
func pkgToMapper(ctx context.Context, view View, pkg Package, uri span.URI) (*ast.File, *protocol.ColumnMapper, error) {
var ph ParseGoHandle
for _, h := range pkg.GetHandles() {
if h.File().Identity().URI == uri {
ph = h
}
}
if ph == nil {
return nil, nil, errors.Errorf("no ParseGoHandle for %s", uri)
}
file, m, err := ph.Cached(ctx)
if file == nil {
return nil, nil, err
}
return file, m, nil
}
func builtinFileToMapper(ctx context.Context, view View, f GoFile, file *ast.File) (*ast.File, *protocol.ColumnMapper, error) {
fh := f.Handle(ctx)
data, _, err := fh.Read(ctx)
if err != nil {
return nil, nil, err
}
converter := span.NewContentConverter(fh.Identity().URI.Filename(), data)
m := &protocol.ColumnMapper{
URI: fh.Identity().URI,
Content: data,
Converter: converter,
}
return nil, m, nil
}
func IsGenerated(ctx context.Context, view View, uri span.URI) bool {
f, err := view.GetFile(ctx, uri)
if err != nil {
return false
}
ph := view.Session().Cache().ParseGoHandle(f.Handle(ctx), ParseHeader)
parsed, _, err := ph.Parse(ctx)
if parsed == nil {
return false
}
tok := view.Session().Cache().FileSet().File(parsed.Pos())
if tok == nil {
return false
}
for _, commentGroup := range parsed.Comments {
for _, comment := range commentGroup.List {
if matched := generatedRx.MatchString(comment.Text); matched {
// Check if comment is at the beginning of the line in source.
if pos := tok.Position(comment.Slash); pos.Column == 1 {
return true
}
}
}
}
return false
}
func nodeToProtocolRange(ctx context.Context, view View, n ast.Node) (protocol.Range, error) {
mrng, err := nodeToMappedRange(ctx, view, n)
if err != nil {
return protocol.Range{}, err
}
return mrng.Range()
}
func objToMappedRange(ctx context.Context, view View, obj types.Object) (mappedRange, error) {
if pkgName, ok := obj.(*types.PkgName); ok {
// An imported Go package has a package-local, unqualified name.
// When the name matches the imported package name, there is no
// identifier in the import spec with the local package name.
//
// For example:
// import "go/ast" // name "ast" matches package name
// import a "go/ast" // name "a" does not match package name
//
// When the identifier does not appear in the source, have the range
// of the object be the point at the beginning of the declaration.
if pkgName.Imported().Name() == pkgName.Name() {
return nameToMappedRange(ctx, view, obj.Pos(), "")
}
}
return nameToMappedRange(ctx, view, obj.Pos(), obj.Name())
}
func nameToMappedRange(ctx context.Context, view View, pos token.Pos, name string) (mappedRange, error) {
return posToRange(ctx, view, pos, pos+token.Pos(len(name)))
}
func nodeToMappedRange(ctx context.Context, view View, n ast.Node) (mappedRange, error) {
return posToRange(ctx, view, n.Pos(), n.End())
}
func posToRange(ctx context.Context, view View, pos, end token.Pos) (mappedRange, error) {
if !pos.IsValid() {
return mappedRange{}, errors.Errorf("invalid position for %v", pos)
}
if !end.IsValid() {
return mappedRange{}, errors.Errorf("invalid position for %v", end)
}
posn := view.Session().Cache().FileSet().Position(pos)
_, m, err := cachedFileToMapper(ctx, view, span.FileURI(posn.Filename))
if err != nil {
return mappedRange{}, err
}
return mappedRange{
m: m,
spanRange: span.NewRange(view.Session().Cache().FileSet(), pos, end),
}, nil
}
// Matches cgo generated comment as well as the proposed standard:
// https://golang.org/s/generatedcode
var generatedRx = regexp.MustCompile(`// .*DO NOT EDIT\.?`)
func DetectLanguage(langID, filename string) FileKind {
switch langID {
case "go":
return Go
case "go.mod":
return Mod
case "go.sum":
return Sum
}
// Fallback to detecting the language based on the file extension.
switch filepath.Ext(filename) {
case ".mod":
return Mod
case ".sum":
return Sum
default: // fallback to Go
return Go
}
}
func (k FileKind) String() string {
switch k {
case Mod:
return "go.mod"
case Sum:
return "go.sum"
default:
return "go"
}
}
// indexExprAtPos returns the index of the expression containing pos.
func indexExprAtPos(pos token.Pos, args []ast.Expr) int {
for i, expr := range args {
if expr.Pos() <= pos && pos <= expr.End() {
return i
}
}
return len(args)
}
func exprAtPos(pos token.Pos, args []ast.Expr) ast.Expr {
for _, expr := range args {
if expr.Pos() <= pos && pos <= expr.End() {
return expr
}
}
return nil
}
// fieldSelections returns the set of fields that can
// be selected from a value of type T.
func fieldSelections(T types.Type) (fields []*types.Var) {
// TODO(adonovan): this algorithm doesn't exclude ambiguous
// selections that match more than one field/method.
// types.NewSelectionSet should do that for us.
seen := make(map[*types.Var]bool) // for termination on recursive types
var visit func(T types.Type)
visit = func(T types.Type) {
if T, ok := deref(T).Underlying().(*types.Struct); ok {
for i := 0; i < T.NumFields(); i++ {
f := T.Field(i)
if seen[f] {
continue
}
seen[f] = true
fields = append(fields, f)
if f.Anonymous() {
visit(f.Type())
}
}
}
}
visit(T)
return fields
}
// resolveInvalid traverses the node of the AST that defines the scope
// containing the declaration of obj, and attempts to find a user-friendly
// name for its invalid type. The resulting Object and its Type are fake.
func resolveInvalid(obj types.Object, node ast.Node, info *types.Info) types.Object {
// Construct a fake type for the object and return a fake object with this type.
formatResult := func(expr ast.Expr) types.Object {
var typename string
switch t := expr.(type) {
case *ast.SelectorExpr:
typename = fmt.Sprintf("%s.%s", t.X, t.Sel)
case *ast.Ident:
typename = t.String()
default:
return nil
}
typ := types.NewNamed(types.NewTypeName(token.NoPos, obj.Pkg(), typename, nil), types.Typ[types.Invalid], nil)
return types.NewVar(obj.Pos(), obj.Pkg(), obj.Name(), typ)
}
var resultExpr ast.Expr
ast.Inspect(node, func(node ast.Node) bool {
switch n := node.(type) {
case *ast.ValueSpec:
for _, name := range n.Names {
if info.Defs[name] == obj {
resultExpr = n.Type
}
}
return false
case *ast.Field: // This case handles parameters and results of a FuncDecl or FuncLit.
for _, name := range n.Names {
if info.Defs[name] == obj {
resultExpr = n.Type
}
}
return false
// TODO(rstambler): Handle range statements.
default:
return true
}
})
return formatResult(resultExpr)
}
func lookupBuiltinDecl(v View, name string) interface{} {
builtinPkg := v.BuiltinPackage()
if builtinPkg == nil || builtinPkg.Scope == nil {
return nil
}
obj := builtinPkg.Scope.Lookup(name)
if obj == nil {
return nil
}
return obj.Decl
}
func isPointer(T types.Type) bool {
_, ok := T.(*types.Pointer)
return ok
}
// deref returns a pointer's element type; otherwise it returns typ.
func deref(typ types.Type) types.Type {
if p, ok := typ.Underlying().(*types.Pointer); ok {
return p.Elem()
}
return typ
}
func isTypeName(obj types.Object) bool {
_, ok := obj.(*types.TypeName)
return ok
}
func isFunc(obj types.Object) bool {
_, ok := obj.(*types.Func)
return ok
}
// typeConversion returns the type being converted to if call is a type
// conversion expression.
func typeConversion(call *ast.CallExpr, info *types.Info) types.Type {
var ident *ast.Ident
switch expr := call.Fun.(type) {
case *ast.Ident:
ident = expr
case *ast.SelectorExpr:
ident = expr.Sel
default:
return nil
}
// Type conversion (e.g. "float64(foo)").
if fun, _ := info.ObjectOf(ident).(*types.TypeName); fun != nil {
return fun.Type()
}
return nil
}
func formatParams(tup *types.Tuple, variadic bool, qf types.Qualifier) []string {
params := make([]string, 0, tup.Len())
for i := 0; i < tup.Len(); i++ {
el := tup.At(i)
typ := types.TypeString(el.Type(), qf)
// Handle a variadic parameter (can only be the final parameter).
if variadic && i == tup.Len()-1 {
typ = strings.Replace(typ, "[]", "...", 1)
}
if el.Name() == "" {
params = append(params, typ)
} else {
params = append(params, el.Name()+" "+typ)
}
}
return params
}
func formatResults(tup *types.Tuple, qf types.Qualifier) ([]string, bool) {
var writeResultParens bool
results := make([]string, 0, tup.Len())
for i := 0; i < tup.Len(); i++ {
if i >= 1 {
writeResultParens = true
}
el := tup.At(i)
typ := types.TypeString(el.Type(), qf)
if el.Name() == "" {
results = append(results, typ)
} else {
if i == 0 {
writeResultParens = true
}
results = append(results, el.Name()+" "+typ)
}
}
return results, writeResultParens
}
// formatType returns the detail and kind for an object of type *types.TypeName.
func formatType(typ types.Type, qf types.Qualifier) (detail string, kind CompletionItemKind) {
if types.IsInterface(typ) {
detail = "interface{...}"
kind = InterfaceCompletionItem
} else if _, ok := typ.(*types.Struct); ok {
detail = "struct{...}"
kind = StructCompletionItem
} else if typ != typ.Underlying() {
detail, kind = formatType(typ.Underlying(), qf)
} else {
detail = types.TypeString(typ, qf)
kind = TypeCompletionItem
}
return detail, kind
}
func formatFunction(params []string, results []string, writeResultParens bool) string {
var detail strings.Builder
detail.WriteByte('(')
for i, p := range params {
if i > 0 {
detail.WriteString(", ")
}
detail.WriteString(p)
}
detail.WriteByte(')')
// Add space between parameters and results.
if len(results) > 0 {
detail.WriteByte(' ')
}
if writeResultParens {
detail.WriteByte('(')
}
for i, p := range results {
if i > 0 {
detail.WriteString(", ")
}
detail.WriteString(p)
}
if writeResultParens {
detail.WriteByte(')')
}
return detail.String()
}