import (
"bytes"
"fmt"
+ "sort"
+ "strconv"
+ "strings"
"unicode/utf8"
)
//
// Using a nil Qualifier is equivalent to using (*Package).Path: the
// object is qualified by the import path, e.g., "encoding/json.Marshal".
-//
type Qualifier func(*Package) string
// RelativeTo returns a Qualifier that fully qualifies members of
newTypeWriter(buf, qf).typ(typ)
}
-// instanceMarker is the prefix for an instantiated type in unexpanded form.
-const instanceMarker = '#'
+// WriteSignature writes the representation of the signature sig to buf,
+// without a leading "func" keyword. The Qualifier controls the printing
+// of package-level objects, and may be nil.
+func WriteSignature(buf *bytes.Buffer, sig *Signature, qf Qualifier) {
+ newTypeWriter(buf, qf).signature(sig)
+}
type typeWriter struct {
- buf *bytes.Buffer
- seen map[Type]bool
- qf Qualifier
+ buf *bytes.Buffer
+ seen map[Type]bool
+ qf Qualifier
+ ctxt *Context // if non-nil, we are type hashing
+ tparams *TypeParamList // local type parameters
+ paramNames bool // if set, write function parameter names, otherwise, write types only
+ tpSubscripts bool // if set, write type parameter indices as subscripts
+ pkgInfo bool // package-annotate first unexported-type field to avoid confusing type description
}
func newTypeWriter(buf *bytes.Buffer, qf Qualifier) *typeWriter {
- return &typeWriter{buf, make(map[Type]bool), qf}
+ return &typeWriter{buf, make(map[Type]bool), qf, nil, nil, true, false, false}
}
-func (w *typeWriter) byte(b byte) { w.buf.WriteByte(b) }
-func (w *typeWriter) string(s string) { w.buf.WriteString(s) }
-func (w *typeWriter) writef(format string, args ...interface{}) { fmt.Fprintf(w.buf, format, args...) }
+func newTypeHasher(buf *bytes.Buffer, ctxt *Context) *typeWriter {
+ assert(ctxt != nil)
+ return &typeWriter{buf, make(map[Type]bool), nil, ctxt, nil, false, false, false}
+}
+
+func (w *typeWriter) byte(b byte) {
+ if w.ctxt != nil {
+ if b == ' ' {
+ b = '#'
+ }
+ w.buf.WriteByte(b)
+ return
+ }
+ w.buf.WriteByte(b)
+ if b == ',' || b == ';' {
+ w.buf.WriteByte(' ')
+ }
+}
+
+func (w *typeWriter) string(s string) {
+ w.buf.WriteString(s)
+}
+
+func (w *typeWriter) error(msg string) {
+ if w.ctxt != nil {
+ panic(msg)
+ }
+ w.buf.WriteString("<" + msg + ">")
+}
func (w *typeWriter) typ(typ Type) {
if w.seen[typ] {
- w.writef("○%T", goTypeName(typ)) // cycle to typ
+ w.error("cycle to " + goTypeName(typ))
return
}
w.seen[typ] = true
switch t := typ.(type) {
case nil:
- w.string("<nil>")
+ w.error("nil")
case *Basic:
// exported basic types go into package unsafe
w.string(t.name)
case *Array:
- w.writef("[%d]", t.len)
+ w.byte('[')
+ w.string(strconv.FormatInt(t.len, 10))
+ w.byte(']')
w.typ(t.elem)
case *Slice:
w.string("struct{")
for i, f := range t.fields {
if i > 0 {
- w.string("; ")
+ w.byte(';')
+ }
+
+ // If disambiguating one struct for another, look for the first unexported field.
+ // Do this first in case of nested structs; tag the first-outermost field.
+ pkgAnnotate := false
+ if w.qf == nil && w.pkgInfo && !isExported(f.name) {
+ // note for embedded types, type name is field name, and "string" etc are lower case hence unexported.
+ pkgAnnotate = true
+ w.pkgInfo = false // only tag once
}
+
// This doesn't do the right thing for embedded type
// aliases where we should print the alias name, not
- // the aliased type (see issue #44410).
+ // the aliased type (see go.dev/issue/44410).
if !f.embedded {
w.string(f.name)
w.byte(' ')
}
w.typ(f.typ)
+ if pkgAnnotate {
+ w.string(" /* package ")
+ w.string(f.pkg.Path())
+ w.string(" */ ")
+ }
if tag := t.Tag(i); tag != "" {
- w.writef(" %q", tag)
+ w.byte(' ')
+ // TODO(gri) If tag contains blanks, replacing them with '#'
+ // in Context.TypeHash may produce another tag
+ // accidentally.
+ w.string(strconv.Quote(tag))
}
}
w.byte('}')
// Unions only appear as (syntactic) embedded elements
// in interfaces and syntactically cannot be empty.
if t.Len() == 0 {
- panic("empty union")
+ w.error("empty union")
+ break
}
for i, t := range t.terms {
if i > 0 {
- w.byte('|')
+ w.string(termSep)
}
if t.tilde {
w.byte('~')
}
case *Interface:
+ if w.ctxt == nil {
+ if t == universeAny.Type() {
+ // When not hashing, we can try to improve type strings by writing "any"
+ // for a type that is pointer-identical to universeAny. This logic should
+ // be deprecated by more robust handling for aliases.
+ w.string("any")
+ break
+ }
+ if t == asNamed(universeComparable.Type()).underlying {
+ w.string("interface{comparable}")
+ break
+ }
+ }
+ if t.implicit {
+ if len(t.methods) == 0 && len(t.embeddeds) == 1 {
+ w.typ(t.embeddeds[0])
+ break
+ }
+ // Something's wrong with the implicit interface.
+ // Print it as such and continue.
+ w.string("/* implicit */ ")
+ }
w.string("interface{")
first := true
- for _, m := range t.methods {
- if !first {
- w.string("; ")
+ if w.ctxt != nil {
+ w.typeSet(t.typeSet())
+ } else {
+ for _, m := range t.methods {
+ if !first {
+ w.byte(';')
+ }
+ first = false
+ w.string(m.name)
+ w.signature(m.typ.(*Signature))
}
- first = false
- w.string(m.name)
- w.signature(m.typ.(*Signature))
- }
- for _, typ := range t.embeddeds {
- if !first {
- w.string("; ")
+ for _, typ := range t.embeddeds {
+ if !first {
+ w.byte(';')
+ }
+ first = false
+ w.typ(typ)
}
- first = false
- w.typ(typ)
}
w.byte('}')
case RecvOnly:
s = "<-chan "
default:
- unreachable()
+ w.error("unknown channel direction")
}
w.string(s)
if parens {
}
case *Named:
- // Instance markers indicate unexpanded instantiated
- // types. Write them to aid debugging, but don't write
- // them when we need an instance hash: whether a type
- // is fully expanded or not doesn't matter for identity.
- if instanceHashing == 0 && t.instPos != nil {
- w.byte(instanceMarker)
+ // If hashing, write a unique prefix for t to represent its identity, since
+ // named type identity is pointer identity.
+ if w.ctxt != nil {
+ w.string(strconv.Itoa(w.ctxt.getID(t)))
}
- w.typeName(t.obj)
- if t.targs != nil {
+ w.typeName(t.obj) // when hashing written for readability of the hash only
+ if t.inst != nil {
// instantiated type
- w.typeList(t.targs.list())
- } else if t.TParams().Len() != 0 {
+ w.typeList(t.inst.targs.list())
+ } else if w.ctxt == nil && t.TypeParams().Len() != 0 { // For type hashing, don't need to format the TypeParams
// parameterized type
- w.tParamList(t.TParams().list())
+ w.tParamList(t.TypeParams().list())
}
case *TypeParam:
- s := "?"
- if t.obj != nil {
- // Optionally write out package for typeparams (like Named).
- // TODO(danscales): this is required for import/export, so
- // we maybe need a separate function that won't be changed
- // for debugging purposes.
- if t.obj.pkg != nil {
- writePackage(w.buf, t.obj.pkg, w.qf)
+ if t.obj == nil {
+ w.error("unnamed type parameter")
+ break
+ }
+ if i := tparamIndex(w.tparams.list(), t); i >= 0 {
+ // The names of type parameters that are declared by the type being
+ // hashed are not part of the type identity. Replace them with a
+ // placeholder indicating their index.
+ w.string(fmt.Sprintf("$%d", i))
+ } else {
+ w.string(t.obj.name)
+ if w.tpSubscripts || w.ctxt != nil {
+ w.string(subscript(t.id))
+ }
+ // If the type parameter name is the same as a predeclared object
+ // (say int), point out where it is declared to avoid confusing
+ // error messages. This doesn't need to be super-elegant; we just
+ // need a clear indication that this is not a predeclared name.
+ if w.ctxt == nil && Universe.Lookup(t.obj.name) != nil {
+ w.string(fmt.Sprintf(" /* with %s declared at %s */", t.obj.name, t.obj.Pos()))
}
- s = t.obj.name
}
- w.string(s + subscript(t.id))
- case *top:
- w.string("⊤")
+ case *_Alias:
+ w.typeName(t.obj)
+ if w.ctxt != nil {
+ // TODO(gri) do we need to print the alias type name, too?
+ w.typ(_Unalias(t.obj.typ))
+ } else {
+ w.string(fmt.Sprintf(" /* = %s */", _Unalias(t.obj.typ)))
+ }
default:
// For externally defined implementations of Type.
}
}
+// typeSet writes a canonical hash for an interface type set.
+func (w *typeWriter) typeSet(s *_TypeSet) {
+ assert(w.ctxt != nil)
+ first := true
+ for _, m := range s.methods {
+ if !first {
+ w.byte(';')
+ }
+ first = false
+ w.string(m.name)
+ w.signature(m.typ.(*Signature))
+ }
+ switch {
+ case s.terms.isAll():
+ // nothing to do
+ case s.terms.isEmpty():
+ w.string(s.terms.String())
+ default:
+ var termHashes []string
+ for _, term := range s.terms {
+ // terms are not canonically sorted, so we sort their hashes instead.
+ var buf bytes.Buffer
+ if term.tilde {
+ buf.WriteByte('~')
+ }
+ newTypeHasher(&buf, w.ctxt).typ(term.typ)
+ termHashes = append(termHashes, buf.String())
+ }
+ sort.Strings(termHashes)
+ if !first {
+ w.byte(';')
+ }
+ w.string(strings.Join(termHashes, "|"))
+ }
+}
+
func (w *typeWriter) typeList(list []Type) {
w.byte('[')
for i, typ := range list {
if i > 0 {
- w.string(", ")
+ w.byte(',')
}
w.typ(typ)
}
// Determine the type parameter and its constraint.
// list is expected to hold type parameter names,
// but don't crash if that's not the case.
- var bound Type
- if tpar != nil {
- bound = tpar.bound // should not be nil but we want to see it if it is
+ if tpar == nil {
+ w.error("nil type parameter")
+ continue
}
-
if i > 0 {
- if bound != prev {
+ if tpar.bound != prev {
// bound changed - write previous one before advancing
w.byte(' ')
w.typ(prev)
}
- w.string(", ")
- }
- prev = bound
-
- if tpar != nil {
- w.typ(tpar)
- } else {
- w.string(tpar.obj.name)
+ w.byte(',')
}
+ prev = tpar.bound
+ w.typ(tpar)
}
if prev != nil {
w.byte(' ')
}
func (w *typeWriter) typeName(obj *TypeName) {
- if obj == nil {
- assert(instanceHashing == 0) // we need an object for instance hashing
- w.string("<Named w/o object>")
- return
- }
- if obj.pkg != nil {
- writePackage(w.buf, obj.pkg, w.qf)
- }
+ w.string(packagePrefix(obj.pkg, w.qf))
w.string(obj.name)
-
- if instanceHashing != 0 {
- // For local defined types, use the (original!) TypeName's scope
- // numbers to disambiguate.
- typ := obj.typ.(*Named)
- // TODO(gri) Figure out why typ.orig != typ.orig.orig sometimes
- // and whether the loop can iterate more than twice.
- // (It seems somehow connected to instance types.)
- for typ.orig != typ {
- typ = typ.orig
- }
- w.writeScopeNumbers(typ.obj.parent)
- }
-}
-
-// writeScopeNumbers writes the number sequence for this scope to buf
-// in the form ".i.j.k" where i, j, k, etc. stand for scope numbers.
-// If a scope is nil or has no parent (such as a package scope), nothing
-// is written.
-func (w *typeWriter) writeScopeNumbers(s *Scope) {
- if s != nil && s.number > 0 {
- w.writeScopeNumbers(s.parent)
- w.writef(".%d", s.number)
- }
}
func (w *typeWriter) tuple(tup *Tuple, variadic bool) {
if tup != nil {
for i, v := range tup.vars {
if i > 0 {
- w.string(", ")
+ w.byte(',')
}
- if v.name != "" {
+ // parameter names are ignored for type identity and thus type hashes
+ if w.ctxt == nil && v.name != "" && w.paramNames {
w.string(v.name)
w.byte(' ')
}
} else {
// special case:
// append(s, "foo"...) leads to signature func([]byte, string...)
- if t := asBasic(typ); t == nil || t.kind != String {
- panic("expected string type")
+ if t, _ := under(typ).(*Basic); t == nil || t.kind != String {
+ w.error("expected string type")
+ continue
}
w.typ(typ)
w.string("...")
w.byte(')')
}
-// WriteSignature writes the representation of the signature sig to buf,
-// without a leading "func" keyword.
-// The Qualifier controls the printing of
-// package-level objects, and may be nil.
-func WriteSignature(buf *bytes.Buffer, sig *Signature, qf Qualifier) {
- newTypeWriter(buf, qf).signature(sig)
-}
-
func (w *typeWriter) signature(sig *Signature) {
- if sig.TParams().Len() != 0 {
- w.tParamList(sig.TParams().list())
+ if sig.TypeParams().Len() != 0 {
+ if w.ctxt != nil {
+ assert(w.tparams == nil)
+ w.tparams = sig.TypeParams()
+ defer func() {
+ w.tparams = nil
+ }()
+ }
+ w.tParamList(sig.TypeParams().list())
}
w.tuple(sig.params, sig.variadic)
}
w.byte(' ')
- if n == 1 && sig.results.vars[0].name == "" {
- // single unnamed result
+ if n == 1 && (w.ctxt != nil || sig.results.vars[0].name == "") {
+ // single unnamed result (if type hashing, name must be ignored)
w.typ(sig.results.vars[0].typ)
return
}