// isLocal reports whether obj is local to some function.
// Precondition: not a struct field or interface method.
func isLocal(obj types.Object) bool {
// [... 5=stmt 4=func 3=file 2=pkg 1=universe]
var depth int
for scope := obj.Parent(); scope != nil; scope = scope.Parent() {
depth++
}
return depth >= 4
}
func isExported(obj types.Object) bool {
// https://golang.org/ref/spec#Exported_identifiers
// An identifier is exported if both:
// the first character of the identifier's name is a Unicode upper case letter (Unicode class "Lu"); and
// the identifier is declared in the package block or it is a field name or method name.
// All other identifiers are not exported.
if !obj.Exported() {
// does not start with an upper case letter
return false
}
if v, ok := obj.(*types.Var); ok && v.IsField() {
// is a field name
return true
}
if sig, ok := obj.Type().(*types.Signature); ok && sig.Recv() != nil {
// is a method name
return true
}
// is declared in the package block
return obj.Parent() == obj.Pkg().Scope()
}
func (g *Grapher) path(obj types.Object) (path []string) {
if path, present := g.paths[obj]; present {
return path
}
var scope *types.Scope
pkgInfo, astPath, _ := g.program.PathEnclosingInterval(obj.Pos(), obj.Pos())
if astPath != nil {
for _, node := range astPath {
if s, hasScope := pkgInfo.Scopes[node]; hasScope {
scope = s
}
}
}
if scope == nil {
scope = obj.Parent()
}
if scope == nil {
// TODO(sqs): make this actually handle cases like the one described in
// https://github.com/sourcegraph/sourcegraph.com/issues/218
log.Printf("Warning: no scope for object %s at pos %s", obj.String(), g.program.Fset.Position(obj.Pos()))
return nil
}
prefix, hasPath := g.scopePaths[scope]
if !hasPath {
panic("no scope path for scope " + scope.String())
}
path = append([]string{}, prefix...)
p := g.program.Fset.Position(obj.Pos())
path = append(path, obj.Name()+uniqID(p))
return path
panic("no scope node for object " + obj.String())
}
func isPkgLevel(o types.Object) bool {
return o.Parent() != nil && o.Parent().Parent() == types.Universe
}
// getDoc returns the doc string associated with types.Object
// parent is the name of the containing scope ("" for global scope)
func (p *Package) getDoc(parent string, o types.Object) string {
n := o.Name()
switch o.(type) {
case *types.Const:
for _, c := range p.doc.Consts {
for _, cn := range c.Names {
if n == cn {
return c.Doc
}
}
}
case *types.Var:
for _, v := range p.doc.Vars {
for _, vn := range v.Names {
if n == vn {
return v.Doc
}
}
}
case *types.Func:
doc := func() string {
if o.Parent() == nil || (o.Parent() != nil && parent != "") {
for _, typ := range p.doc.Types {
if typ.Name != parent {
continue
}
if o.Parent() == nil {
for _, m := range typ.Methods {
if m.Name == n {
return m.Doc
}
}
} else {
for _, m := range typ.Funcs {
if m.Name == n {
return m.Doc
}
}
}
}
} else {
for _, f := range p.doc.Funcs {
if n == f.Name {
return f.Doc
}
}
}
return ""
}()
sig := o.Type().(*types.Signature)
parseFn := func(tup *types.Tuple) []string {
params := []string{}
if tup == nil {
return params
}
for i := 0; i < tup.Len(); i++ {
paramVar := tup.At(i)
paramType := p.syms.symtype(paramVar.Type()).pysig
if paramVar.Name() != "" {
paramType = fmt.Sprintf("%s %s", paramType, paramVar.Name())
}
params = append(params, paramType)
}
return params
}
params := parseFn(sig.Params())
results := parseFn(sig.Results())
paramString := strings.Join(params, ", ")
resultString := strings.Join(results, ", ")
//FIXME(sbinet): add receiver for methods?
docSig := fmt.Sprintf("%s(%s) %s", o.Name(), paramString, resultString)
if doc != "" {
doc = fmt.Sprintf("%s\n\n%s", docSig, doc)
} else {
doc = docSig
}
return doc
case *types.TypeName:
for _, t := range p.doc.Types {
if n == t.Name {
return t.Doc
}
}
default:
// TODO(sbinet)
panic(fmt.Errorf("not yet supported: %v (%T)", o, o))
}
return ""
}
// checkInLexicalScope performs safety checks that a renaming does not
// change the lexical reference structure of the specified package.
//
// For objects in lexical scope, there are three kinds of conflicts:
// same-, sub-, and super-block conflicts. We will illustrate all three
// using this example:
//
// var x int
// var z int
//
// func f(y int) {
// print(x)
// print(y)
// }
//
// Renaming x to z encounters a SAME-BLOCK CONFLICT, because an object
// with the new name already exists, defined in the same lexical block
// as the old object.
//
// Renaming x to y encounters a SUB-BLOCK CONFLICT, because there exists
// a reference to x from within (what would become) a hole in its scope.
// The definition of y in an (inner) sub-block would cast a shadow in
// the scope of the renamed variable.
//
// Renaming y to x encounters a SUPER-BLOCK CONFLICT. This is the
// converse situation: there is an existing definition of the new name
// (x) in an (enclosing) super-block, and the renaming would create a
// hole in its scope, within which there exist references to it. The
// new name casts a shadow in scope of the existing definition of x in
// the super-block.
//
// Removing the old name (and all references to it) is always safe, and
// requires no checks.
//
func (r *renamer) checkInLexicalScope(from types.Object, info *loader.PackageInfo) {
b := from.Parent() // the block defining the 'from' object
if b != nil {
toBlock, to := b.LookupParent(r.to, from.Parent().End())
if toBlock == b {
// same-block conflict
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
r.errorf(to.Pos(), "\tconflicts with %s in same block",
objectKind(to))
return
} else if toBlock != nil {
// Check for super-block conflict.
// The name r.to is defined in a superblock.
// Is that name referenced from within this block?
forEachLexicalRef(info, to, func(id *ast.Ident, block *types.Scope) bool {
_, obj := lexicalLookup(block, from.Name(), id.Pos())
if obj == from {
// super-block conflict
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
r.errorf(id.Pos(), "\twould shadow this reference")
r.errorf(to.Pos(), "\tto the %s declared here",
objectKind(to))
return false // stop
}
return true
})
}
}
// Check for sub-block conflict.
// Is there an intervening definition of r.to between
// the block defining 'from' and some reference to it?
forEachLexicalRef(info, from, func(id *ast.Ident, block *types.Scope) bool {
// Find the block that defines the found reference.
// It may be an ancestor.
fromBlock, _ := lexicalLookup(block, from.Name(), id.Pos())
// See what r.to would resolve to in the same scope.
toBlock, to := lexicalLookup(block, r.to, id.Pos())
if to != nil {
// sub-block conflict
if deeper(toBlock, fromBlock) {
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
r.errorf(id.Pos(), "\twould cause this reference to become shadowed")
r.errorf(to.Pos(), "\tby this intervening %s definition",
objectKind(to))
return false // stop
}
}
return true
})
// Renaming a type that is used as an embedded field
// requires renaming the field too. e.g.
// type T int // if we rename this to U..
// var s struct {T}
// print(s.T) // ...this must change too
if _, ok := from.(*types.TypeName); ok {
for id, obj := range info.Uses {
if obj == from {
if field := info.Defs[id]; field != nil {
r.check(field)
}
}
}
}
}
