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// 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/printer"
"go/token"
"go/types"
"path/filepath"
"regexp"
"sort"
"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 newMappedRange(fset *token.FileSet, m *protocol.ColumnMapper, start, end token.Pos) mappedRange {
return mappedRange{
spanRange: span.Range{
FileSet: fset,
Start: start,
End: end,
Converter: m.Converter,
},
m: m,
}
}
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
}
// getParsedFile is a convenience function that extracts the Package and ParseGoHandle for a File in a Snapshot.
// selectPackage is typically Narrowest/WidestCheckPackageHandle below.
func getParsedFile(ctx context.Context, snapshot Snapshot, fh FileHandle, selectPackage PackagePolicy) (Package, ParseGoHandle, error) {
phs, err := snapshot.PackageHandles(ctx, fh)
if err != nil {
return nil, nil, err
}
ph, err := selectPackage(phs)
if err != nil {
return nil, nil, err
}
pkg, err := ph.Check(ctx)
if err != nil {
return nil, nil, err
}
pgh, err := pkg.File(fh.Identity().URI)
return pkg, pgh, err
}
type PackagePolicy func([]PackageHandle) (PackageHandle, error)
// NarrowestCheckPackageHandle 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 NarrowestCheckPackageHandle(handles []PackageHandle) (PackageHandle, error) {
if len(handles) < 1 {
return nil, errors.Errorf("no CheckPackageHandles")
}
result := handles[0]
for _, handle := range handles[1:] {
if result == nil || len(handle.CompiledGoFiles()) < len(result.CompiledGoFiles()) {
result = handle
}
}
if result == nil {
return nil, errors.Errorf("nil CheckPackageHandles have been returned")
}
return result, nil
}
// WidestCheckPackageHandle returns the CheckPackageHandle containing the most files.
//
// This is useful for something like diagnostics, where we'd prefer to offer diagnostics
// for as many files as possible.
func WidestCheckPackageHandle(handles []PackageHandle) (PackageHandle, error) {
if len(handles) < 1 {
return nil, errors.Errorf("no CheckPackageHandles")
}
result := handles[0]
for _, handle := range handles[1:] {
if result == nil || len(handle.CompiledGoFiles()) > len(result.CompiledGoFiles()) {
result = handle
}
}
if result == nil {
return nil, errors.Errorf("nil CheckPackageHandles have been returned")
}
return result, nil
}
// SpecificPackageHandle creates a PackagePolicy to select a
// particular PackageHandle when you alread know the one you want.
func SpecificPackageHandle(desiredID string) PackagePolicy {
return func(handles []PackageHandle) (PackageHandle, error) {
for _, h := range handles {
if h.ID() == desiredID {
return h, nil
}
}
return nil, fmt.Errorf("no package handle with expected id %q", desiredID)
}
}
func IsGenerated(ctx context.Context, view View, uri span.URI) bool {
fh, err := view.Snapshot().GetFile(ctx, uri)
if err != nil {
return false
}
ph := view.Session().Cache().ParseGoHandle(fh, ParseHeader)
parsed, _, _, err := ph.Parse(ctx)
if err != 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, m *protocol.ColumnMapper, n ast.Node) (protocol.Range, error) {
mrng, err := nodeToMappedRange(view, m, n)
if err != nil {
return protocol.Range{}, err
}
return mrng.Range()
}
func objToMappedRange(v View, pkg Package, 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 import path, including quotes.
if pkgName.Imported().Name() == pkgName.Name() {
return posToMappedRange(v, pkg, obj.Pos(), obj.Pos()+token.Pos(len(pkgName.Imported().Path())+2))
}
}
return nameToMappedRange(v, pkg, obj.Pos(), obj.Name())
}
func nameToMappedRange(v View, pkg Package, pos token.Pos, name string) (mappedRange, error) {
return posToMappedRange(v, pkg, pos, pos+token.Pos(len(name)))
}
func nodeToMappedRange(view View, m *protocol.ColumnMapper, n ast.Node) (mappedRange, error) {
return posToRange(view, m, n.Pos(), n.End())
}
func posToMappedRange(v View, pkg Package, pos, end token.Pos) (mappedRange, error) {
logicalFilename := v.Session().Cache().FileSet().File(pos).Position(pos).Filename
m, err := v.FindMapperInPackage(pkg, span.FileURI(logicalFilename))
if err != nil {
return mappedRange{}, err
}
return posToRange(v, m, pos, end)
}
func posToRange(view View, m *protocol.ColumnMapper, 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)
}
return newMappedRange(view.Session().Cache().FileSet(), m, 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"
}
}
// Returns the index and the node whose position is contained inside the node list.
func nodeAtPos(nodes []ast.Node, pos token.Pos) (ast.Node, int) {
if nodes == nil {
return nil, -1
}
for i, node := range nodes {
if node.Pos() <= pos && pos <= node.End() {
return node, i
}
}
return nil, -1
}
// 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
}
// typeIsValid reports whether typ doesn't contain any Invalid types.
func typeIsValid(typ types.Type) bool {
switch typ := typ.Underlying().(type) {
case *types.Basic:
return typ.Kind() != types.Invalid
case *types.Array:
return typeIsValid(typ.Elem())
case *types.Slice:
return typeIsValid(typ.Elem())
case *types.Pointer:
return typeIsValid(typ.Elem())
case *types.Map:
return typeIsValid(typ.Key()) && typeIsValid(typ.Elem())
case *types.Chan:
return typeIsValid(typ.Elem())
case *types.Signature:
return typeIsValid(typ.Params()) && typeIsValid(typ.Results())
case *types.Tuple:
for i := 0; i < typ.Len(); i++ {
if !typeIsValid(typ.At(i).Type()) {
return false
}
}
return true
case *types.Struct, *types.Interface, *types.Named:
// Don't bother checking structs, interfaces, or named types for validity.
return true
default:
return false
}
}
// 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(fset *token.FileSet, obj types.Object, node ast.Node, info *types.Info) types.Object {
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
default:
return true
}
})
// Construct a fake type for the object and return a fake object with this type.
typename := formatNode(fset, resultExpr)
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)
}
func isPointer(T types.Type) bool {
_, ok := T.(*types.Pointer)
return ok
}
func isVar(obj types.Object) bool {
_, ok := obj.(*types.Var)
return ok
}
// deref returns a pointer's element type, traversing as many levels as needed.
// Otherwise it returns typ.
func deref(typ types.Type) types.Type {
for {
p, ok := typ.Underlying().(*types.Pointer)
if !ok {
return typ
}
typ = p.Elem()
}
}
func isTypeName(obj types.Object) bool {
_, ok := obj.(*types.TypeName)
return ok
}
func isFunc(obj types.Object) bool {
_, ok := obj.(*types.Func)
return ok
}
func isEmptyInterface(T types.Type) bool {
intf, _ := T.(*types.Interface)
return intf != nil && intf.NumMethods() == 0
}
func isUntyped(T types.Type) bool {
if basic, ok := T.(*types.Basic); ok {
return basic.Info()&types.IsUntyped > 0
}
return false
}
// isSelector returns the enclosing *ast.SelectorExpr when pos is in the
// selector.
func enclosingSelector(path []ast.Node, pos token.Pos) *ast.SelectorExpr {
if len(path) == 0 {
return nil
}
if sel, ok := path[0].(*ast.SelectorExpr); ok {
return sel
}
if _, ok := path[0].(*ast.Ident); ok && len(path) > 1 {
if sel, ok := path[1].(*ast.SelectorExpr); ok && pos >= sel.Sel.Pos() {
return sel
}
}
return nil
}
func enclosingValueSpec(path []ast.Node, pos token.Pos) *ast.ValueSpec {
for _, n := range path {
if vs, ok := n.(*ast.ValueSpec); ok {
return vs
}
}
return nil
}
// 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
}
// fieldsAccessible returns whether s has at least one field accessible by p.
func fieldsAccessible(s *types.Struct, p *types.Package) bool {
for i := 0; i < s.NumFields(); i++ {
f := s.Field(i)
if f.Exported() || f.Pkg() == p {
return true
}
}
return false
}
func formatParams(s Snapshot, pkg Package, sig *types.Signature, qf types.Qualifier) []string {
params := make([]string, 0, sig.Params().Len())
for i := 0; i < sig.Params().Len(); i++ {
el := sig.Params().At(i)
typ, err := formatFieldType(s, pkg, el, qf)
if err != nil {
typ = types.TypeString(el.Type(), qf)
}
// Handle a variadic parameter (can only be the final parameter).
if sig.Variadic() && i == sig.Params().Len()-1 {
typ = strings.Replace(typ, "[]", "...", 1)
}
if el.Name() == "" {
params = append(params, typ)
} else {
params = append(params, el.Name()+" "+typ)
}
}
return params
}
func formatFieldType(s Snapshot, srcpkg Package, obj types.Object, qf types.Qualifier) (string, error) {
file, pkg, err := s.View().FindPosInPackage(srcpkg, obj.Pos())
if err != nil {
return "", err
}
ident, err := findIdentifier(s, pkg, file, obj.Pos())
if err != nil {
return "", err
}
if i := ident.ident; i == nil || i.Obj == nil || i.Obj.Decl == nil {
return "", errors.Errorf("no object for ident %v", i.Name)
}
f, ok := ident.ident.Obj.Decl.(*ast.Field)
if !ok {
return "", errors.Errorf("ident %s is not a field type", ident.Name)
}
return formatNode(s.View().Session().Cache().FileSet(), f.Type), nil
}
func formatNode(fset *token.FileSet, n ast.Node) string {
var buf strings.Builder
if err := printer.Fprint(&buf, fset, n); err != nil {
return ""
}
return buf.String()
}
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 protocol.CompletionItemKind) {
if types.IsInterface(typ) {
detail = "interface{...}"
kind = protocol.InterfaceCompletion
} else if _, ok := typ.(*types.Struct); ok {
detail = "struct{...}"
kind = protocol.StructCompletion
} else if typ != typ.Underlying() {
detail, kind = formatType(typ.Underlying(), qf)
} else {
detail = types.TypeString(typ, qf)
kind = protocol.ClassCompletion
}
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()
}
func SortDiagnostics(d []Diagnostic) {
sort.Slice(d, func(i int, j int) bool {
return CompareDiagnostic(d[i], d[j]) < 0
})
}
func CompareDiagnostic(a, b Diagnostic) int {
if r := protocol.CompareRange(a.Range, b.Range); r != 0 {
return r
}
if a.Message < b.Message {
return -1
}
if a.Message == b.Message {
return 0
}
return 1
}