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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"
"go/ast"
"go/printer"
"go/token"
"go/types"
"path/filepath"
"regexp"
"sort"
"strconv"
"strings"
"golang.org/x/tools/gopls/internal/lsp/protocol"
"golang.org/x/tools/gopls/internal/lsp/safetoken"
"golang.org/x/tools/gopls/internal/span"
"golang.org/x/tools/internal/bug"
"golang.org/x/tools/internal/tokeninternal"
"golang.org/x/tools/internal/typeparams"
)
// IsGenerated gets and reads the file denoted by uri and reports
// whether it contains a "generated file" comment as described at
// https://golang.org/s/generatedcode.
//
// TODO(adonovan): opt: this function does too much.
// Move snapshot.ReadFile into the caller (most of which have already done it).
func IsGenerated(ctx context.Context, snapshot Snapshot, uri span.URI) bool {
fh, err := snapshot.ReadFile(ctx, uri)
if err != nil {
return false
}
pgf, err := snapshot.ParseGo(ctx, fh, ParseHeader)
if err != nil {
return false
}
for _, commentGroup := range pgf.File.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 safetoken.Position(pgf.Tok, comment.Slash).Column == 1 {
return true
}
}
}
}
return false
}
// adjustedObjEnd returns the end position of obj, possibly modified for
// package names.
//
// TODO(rfindley): eliminate this function, by inlining it at callsites where
// it makes sense.
func adjustedObjEnd(obj types.Object) token.Pos {
nameLen := len(obj.Name())
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() {
nameLen = len(pkgName.Imported().Path()) + len(`""`)
}
}
return obj.Pos() + token.Pos(nameLen)
}
// Matches cgo generated comment as well as the proposed standard:
//
// https://golang.org/s/generatedcode
var generatedRx = regexp.MustCompile(`// .*DO NOT EDIT\.?`)
// FileKindForLang returns the file kind associated with the given language ID,
// or UnknownKind if the language ID is not recognized.
func FileKindForLang(langID string) FileKind {
switch langID {
case "go":
return Go
case "go.mod":
return Mod
case "go.sum":
return Sum
case "tmpl", "gotmpl":
return Tmpl
case "go.work":
return Work
default:
return UnknownKind
}
}
// nodeAtPos 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
}
// FormatNode returns the "pretty-print" output for an ast node.
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()
}
// FormatNodeFile is like FormatNode, but requires only the token.File for the
// syntax containing the given ast node.
func FormatNodeFile(file *token.File, n ast.Node) string {
fset := FileSetFor(file)
return FormatNode(fset, n)
}
// FileSetFor returns a new FileSet containing a sequence of new Files with
// the same base, size, and line as the input files, for use in APIs that
// require a FileSet.
//
// Precondition: the input files must be non-overlapping, and sorted in order
// of their Base.
func FileSetFor(files ...*token.File) *token.FileSet {
fset := token.NewFileSet()
for _, f := range files {
f2 := fset.AddFile(f.Name(), f.Base(), f.Size())
lines := tokeninternal.GetLines(f)
f2.SetLines(lines)
}
return fset
}
// Deref returns a pointer's element type, traversing as many levels as needed.
// Otherwise it returns typ.
//
// It can return a pointer type for cyclic types (see golang/go#45510).
func Deref(typ types.Type) types.Type {
var seen map[types.Type]struct{}
for {
p, ok := typ.Underlying().(*types.Pointer)
if !ok {
return typ
}
if _, ok := seen[p.Elem()]; ok {
return typ
}
typ = p.Elem()
if seen == nil {
seen = make(map[types.Type]struct{})
}
seen[typ] = struct{}{}
}
}
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.Source < b.Source {
return -1
}
if a.Source > b.Source {
return +1
}
if a.Message < b.Message {
return -1
}
if a.Message > b.Message {
return +1
}
return 0
}
// findFileInDeps finds package metadata containing URI in the transitive
// dependencies of m. When using the Go command, the answer is unique.
//
// TODO(rfindley): refactor to share logic with findPackageInDeps?
func findFileInDeps(s MetadataSource, m *Metadata, uri span.URI) *Metadata {
seen := make(map[PackageID]bool)
var search func(*Metadata) *Metadata
search = func(m *Metadata) *Metadata {
if seen[m.ID] {
return nil
}
seen[m.ID] = true
for _, cgf := range m.CompiledGoFiles {
if cgf == uri {
return m
}
}
for _, dep := range m.DepsByPkgPath {
m := s.Metadata(dep)
if m == nil {
bug.Reportf("nil metadata for %q", dep)
continue
}
if found := search(m); found != nil {
return found
}
}
return nil
}
return search(m)
}
// UnquoteImportPath returns the unquoted import path of s,
// or "" if the path is not properly quoted.
func UnquoteImportPath(s *ast.ImportSpec) ImportPath {
path, err := strconv.Unquote(s.Path.Value)
if err != nil {
return ""
}
return ImportPath(path)
}
// NodeContains returns true if a node encloses a given position pos.
func NodeContains(n ast.Node, pos token.Pos) bool {
return n != nil && n.Pos() <= pos && pos <= n.End()
}
// CollectScopes returns all scopes in an ast path, ordered as innermost scope
// first.
func CollectScopes(info *types.Info, path []ast.Node, pos token.Pos) []*types.Scope {
// scopes[i], where i<len(path), is the possibly nil Scope of path[i].
var scopes []*types.Scope
for _, n := range path {
// Include *FuncType scope if pos is inside the function body.
switch node := n.(type) {
case *ast.FuncDecl:
if node.Body != nil && NodeContains(node.Body, pos) {
n = node.Type
}
case *ast.FuncLit:
if node.Body != nil && NodeContains(node.Body, pos) {
n = node.Type
}
}
scopes = append(scopes, info.Scopes[n])
}
return scopes
}
// Qualifier returns a function that appropriately formats a types.PkgName
// appearing in a *ast.File.
func Qualifier(f *ast.File, pkg *types.Package, info *types.Info) types.Qualifier {
// Construct mapping of import paths to their defined or implicit names.
imports := make(map[*types.Package]string)
for _, imp := range f.Imports {
var obj types.Object
if imp.Name != nil {
obj = info.Defs[imp.Name]
} else {
obj = info.Implicits[imp]
}
if pkgname, ok := obj.(*types.PkgName); ok {
imports[pkgname.Imported()] = pkgname.Name()
}
}
// Define qualifier to replace full package paths with names of the imports.
return func(p *types.Package) string {
if p == pkg {
return ""
}
if name, ok := imports[p]; ok {
if name == "." {
return ""
}
return name
}
return p.Name()
}
}
// requalifier returns a function that re-qualifies identifiers and qualified
// identifiers contained in targetFile using the given metadata qualifier.
func requalifier(s MetadataSource, targetFile *ast.File, targetMeta *Metadata, mq MetadataQualifier) func(string) string {
qm := map[string]string{
"": mq(targetMeta.Name, "", targetMeta.PkgPath),
}
// Construct mapping of import paths to their defined or implicit names.
for _, imp := range targetFile.Imports {
name, pkgName, impPath, pkgPath := importInfo(s, imp, targetMeta)
// Re-map the target name for the source file.
qm[name] = mq(pkgName, impPath, pkgPath)
}
return func(name string) string {
if newName, ok := qm[name]; ok {
return newName
}
return name
}
}
// A MetadataQualifier is a function that qualifies an identifier declared in a
// package with the given package name, import path, and package path.
//
// In scenarios where metadata is missing the provided PackageName and
// PackagePath may be empty, but ImportPath must always be non-empty.
type MetadataQualifier func(PackageName, ImportPath, PackagePath) string
// MetadataQualifierForFile returns a metadata qualifier that chooses the best
// qualification of an imported package relative to the file f in package with
// metadata m.
func MetadataQualifierForFile(s MetadataSource, f *ast.File, m *Metadata) MetadataQualifier {
// Record local names for import paths.
localNames := make(map[ImportPath]string) // local names for imports in f
for _, imp := range f.Imports {
name, _, impPath, _ := importInfo(s, imp, m)
localNames[impPath] = name
}
// Record a package path -> import path mapping.
inverseDeps := make(map[PackageID]PackagePath)
for path, id := range m.DepsByPkgPath {
inverseDeps[id] = path
}
importsByPkgPath := make(map[PackagePath]ImportPath) // best import paths by pkgPath
for impPath, id := range m.DepsByImpPath {
if id == "" {
continue
}
pkgPath := inverseDeps[id]
_, hasPath := importsByPkgPath[pkgPath]
_, hasImp := localNames[impPath]
// In rare cases, there may be multiple import paths with the same package
// path. In such scenarios, prefer an import path that already exists in
// the file.
if !hasPath || hasImp {
importsByPkgPath[pkgPath] = impPath
}
}
return func(pkgName PackageName, impPath ImportPath, pkgPath PackagePath) string {
// If supplied, translate the package path to an import path in the source
// package.
if pkgPath != "" {
if srcImp := importsByPkgPath[pkgPath]; srcImp != "" {
impPath = srcImp
}
if pkgPath == m.PkgPath {
return ""
}
}
if localName, ok := localNames[impPath]; ok && impPath != "" {
return string(localName)
}
if pkgName != "" {
return string(pkgName)
}
idx := strings.LastIndexByte(string(impPath), '/')
return string(impPath[idx+1:])
}
}
// importInfo collects information about the import specified by imp,
// extracting its file-local name, package name, import path, and package path.
//
// If metadata is missing for the import, the resulting package name and
// package path may be empty, and the file local name may be guessed based on
// the import path.
//
// Note: previous versions of this helper used a PackageID->PackagePath map
// extracted from m, for extracting package path even in the case where
// metadata for a dep was missing. This should not be necessary, as we should
// always have metadata for IDs contained in DepsByPkgPath.
func importInfo(s MetadataSource, imp *ast.ImportSpec, m *Metadata) (string, PackageName, ImportPath, PackagePath) {
var (
name string // local name
pkgName PackageName
impPath = UnquoteImportPath(imp)
pkgPath PackagePath
)
// If the import has a local name, use it.
if imp.Name != nil {
name = imp.Name.Name
}
// Try to find metadata for the import. If successful and there is no local
// name, the package name is the local name.
if depID := m.DepsByImpPath[impPath]; depID != "" {
if depm := s.Metadata(depID); depm != nil {
if name == "" {
name = string(depm.Name)
}
pkgName = depm.Name
pkgPath = depm.PkgPath
}
}
// If the local name is still unknown, guess it based on the import path.
if name == "" {
idx := strings.LastIndexByte(string(impPath), '/')
name = string(impPath[idx+1:])
}
return name, pkgName, impPath, pkgPath
}
// isDirective reports whether c is a comment directive.
//
// Copied and adapted from go/src/go/ast/ast.go.
func isDirective(c string) bool {
if len(c) < 3 {
return false
}
if c[1] != '/' {
return false
}
//-style comment (no newline at the end)
c = c[2:]
if len(c) == 0 {
// empty line
return false
}
// "//line " is a line directive.
// (The // has been removed.)
if strings.HasPrefix(c, "line ") {
return true
}
// "//[a-z0-9]+:[a-z0-9]"
// (The // has been removed.)
colon := strings.Index(c, ":")
if colon <= 0 || colon+1 >= len(c) {
return false
}
for i := 0; i <= colon+1; i++ {
if i == colon {
continue
}
b := c[i]
if !('a' <= b && b <= 'z' || '0' <= b && b <= '9') {
return false
}
}
return true
}
// InDir checks whether path is in the file tree rooted at dir.
// It checks only the lexical form of the file names.
// It does not consider symbolic links.
//
// Copied from go/src/cmd/go/internal/search/search.go.
func InDir(dir, path string) bool {
pv := strings.ToUpper(filepath.VolumeName(path))
dv := strings.ToUpper(filepath.VolumeName(dir))
path = path[len(pv):]
dir = dir[len(dv):]
switch {
default:
return false
case pv != dv:
return false
case len(path) == len(dir):
if path == dir {
return true
}
return false
case dir == "":
return path != ""
case len(path) > len(dir):
if dir[len(dir)-1] == filepath.Separator {
if path[:len(dir)] == dir {
return path[len(dir):] != ""
}
return false
}
if path[len(dir)] == filepath.Separator && path[:len(dir)] == dir {
if len(path) == len(dir)+1 {
return true
}
return path[len(dir)+1:] != ""
}
return false
}
}
// IsValidImport returns whether importPkgPath is importable
// by pkgPath
func IsValidImport(pkgPath, importPkgPath PackagePath) bool {
i := strings.LastIndex(string(importPkgPath), "/internal/")
if i == -1 {
return true
}
// TODO(rfindley): this looks wrong: IsCommandLineArguments is meant to
// operate on package IDs, not package paths.
if IsCommandLineArguments(PackageID(pkgPath)) {
return true
}
// TODO(rfindley): this is wrong. mod.testx/p should not be able to
// import mod.test/internal: https://go.dev/play/p/-Ca6P-E4V4q
return strings.HasPrefix(string(pkgPath), string(importPkgPath[:i]))
}
// IsCommandLineArguments reports whether a given value denotes
// "command-line-arguments" package, which is a package with an unknown ID
// created by the go command. It can have a test variant, which is why callers
// should not check that a value equals "command-line-arguments" directly.
func IsCommandLineArguments(id PackageID) bool {
return strings.Contains(string(id), "command-line-arguments")
}
// embeddedIdent returns the type name identifier for an embedding x, if x in a
// valid embedding. Otherwise, it returns nil.
//
// Spec: An embedded field must be specified as a type name T or as a pointer
// to a non-interface type name *T
func embeddedIdent(x ast.Expr) *ast.Ident {
if star, ok := x.(*ast.StarExpr); ok {
x = star.X
}
switch ix := x.(type) { // check for instantiated receivers
case *ast.IndexExpr:
x = ix.X
case *typeparams.IndexListExpr:
x = ix.X
}
switch x := x.(type) {
case *ast.Ident:
return x
case *ast.SelectorExpr:
if _, ok := x.X.(*ast.Ident); ok {
return x.Sel
}
}
return nil
}