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cmd/api: allow extension of interfaces with unexported methods

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Fixes #4061.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6525047
This commit is contained in:
Russ Cox 2012-09-18 15:57:03 -04:00
parent 8ed026e783
commit a29f3136b4
4 changed files with 57 additions and 19 deletions
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35
src/cmd/api/goapi.go
View file

@ -892,15 +892,18 @@ type method struct {
sig string // "([]byte) (int, error)", from funcSigString
}
// interfaceMethods returns the expanded list of methods for an interface.
// interfaceMethods returns the expanded list of exported methods for an interface.
// The boolean complete reports whether the list contains all methods (that is, the
// interface has no unexported methods).
// pkg is the complete package name ("net/http")
// iname is the interface name.
func (w *Walker) interfaceMethods(pkg, iname string) (methods []method) {
func (w *Walker) interfaceMethods(pkg, iname string) (methods []method, complete bool) {
t, ok := w.interfaces[pkgSymbol{pkg, iname}]
if !ok {
log.Fatalf("failed to find interface %s.%s", pkg, iname)
}
complete = true
for _, f := range t.Methods.List {
typ := f.Type
switch tv := typ.(type) {
@ -912,6 +915,8 @@ func (w *Walker) interfaceMethods(pkg, iname string) (methods []method) {
name: mname.Name,
sig: w.funcSigString(ft),
})
} else {
complete = false
}
}
case *ast.Ident:
@ -927,7 +932,9 @@ func (w *Walker) interfaceMethods(pkg, iname string) (methods []method) {
log.Fatalf("unexported embedded interface %q in exported interface %s.%s; confused",
embedded, pkg, iname)
}
methods = append(methods, w.interfaceMethods(pkg, embedded)...)
m, c := w.interfaceMethods(pkg, embedded)
methods = append(methods, m...)
complete = complete && c
case *ast.SelectorExpr:
lhs := w.nodeString(tv.X)
rhs := w.nodeString(tv.Sel)
@ -935,7 +942,9 @@ func (w *Walker) interfaceMethods(pkg, iname string) (methods []method) {
if !ok {
log.Fatalf("can't resolve selector %q in interface %s.%s", lhs, pkg, iname)
}
methods = append(methods, w.interfaceMethods(fpkg, rhs)...)
m, c := w.interfaceMethods(fpkg, rhs)
methods = append(methods, m...)
complete = complete && c
default:
log.Fatalf("unknown type %T in interface field", typ)
}
@ -945,14 +954,28 @@ func (w *Walker) interfaceMethods(pkg, iname string) (methods []method) {
func (w *Walker) walkInterfaceType(name string, t *ast.InterfaceType) {
methNames := []string{}
pop := w.pushScope("type " + name + " interface")
for _, m := range w.interfaceMethods(w.curPackageName, name) {
methods, complete := w.interfaceMethods(w.curPackageName, name)
for _, m := range methods {
methNames = append(methNames, m.name)
w.emitFeature(fmt.Sprintf("%s%s", m.name, m.sig))
}
if !complete {
// The method set has unexported methods, so all the
// implementations are provided by the same package,
// so the method set can be extended. Instead of recording
// the full set of names (below), record only that there were
// unexported methods. (If the interface shrinks, we will notice
// because a method signature emitted during the last loop,
// will disappear.)
w.emitFeature("unexported methods")
}
pop()
if !complete {
return
}
sort.Strings(methNames)
if len(methNames) == 0 {
w.emitFeature(fmt.Sprintf("type %s interface {}", name))