// MethodSet returns the method set of type T. It is thread-safe.
//
// If cache is nil, this function is equivalent to types.NewMethodSet(T).
// Utility functions can thus expose an optional *MethodSetCache
// parameter to clients that care about performance.
//
func (cache *MethodSetCache) MethodSet(T types.Type) *types.MethodSet {
if cache == nil {
return types.NewMethodSet(T)
}
cache.mu.Lock()
defer cache.mu.Unlock()
switch T := T.(type) {
case *types.Named:
return cache.lookupNamed(T).value
case *types.Pointer:
if N, ok := T.Elem().(*types.Named); ok {
return cache.lookupNamed(N).pointer
}
}
// all other types
// (The map uses pointer equivalence, not type identity.)
mset := cache.others[T]
if mset == nil {
mset = types.NewMethodSet(T)
if cache.others == nil {
cache.others = make(map[types.Type]*types.MethodSet)
}
cache.others[T] = mset
}
return mset
}
// IntuitiveMethodSet returns the intuitive method set of a type, T.
//
// The result contains MethodSet(T) and additionally, if T is a
// concrete type, methods belonging to *T if there is no identically
// named method on T itself. This corresponds to user intuition about
// method sets; this function is intended only for user interfaces.
//
// The order of the result is as for types.MethodSet(T).
//
func IntuitiveMethodSet(T types.Type, msets *MethodSetCache) []*types.Selection {
var result []*types.Selection
mset := msets.MethodSet(T)
if _, ok := T.Underlying().(*types.Interface); ok {
for i, n := 0, mset.Len(); i < n; i++ {
result = append(result, mset.At(i))
}
} else {
pmset := msets.MethodSet(types.NewPointer(T))
for i, n := 0, pmset.Len(); i < n; i++ {
meth := pmset.At(i)
if m := mset.Lookup(meth.Obj().Pkg(), meth.Obj().Name()); m != nil {
meth = m
}
result = append(result, meth)
}
}
return result
}
// hashFor computes the hash of t.
func (h Hasher) hashFor(t types.Type) uint32 {
// See Identical for rationale.
switch t := t.(type) {
case *types.Basic:
return uint32(t.Kind())
case *types.Array:
return 9043 + 2*uint32(t.Len()) + 3*h.Hash(t.Elem())
case *types.Slice:
return 9049 + 2*h.Hash(t.Elem())
case *types.Struct:
var hash uint32 = 9059
for i, n := 0, t.NumFields(); i < n; i++ {
f := t.Field(i)
if f.Anonymous() {
hash += 8861
}
hash += hashString(t.Tag(i))
hash += hashString(f.Name()) // (ignore f.Pkg)
hash += h.Hash(f.Type())
}
return hash
case *types.Pointer:
return 9067 + 2*h.Hash(t.Elem())
case *types.Signature:
var hash uint32 = 9091
if t.Variadic() {
hash *= 8863
}
return hash + 3*h.hashTuple(t.Params()) + 5*h.hashTuple(t.Results())
case *types.Interface:
var hash uint32 = 9103
for i, n := 0, t.NumMethods(); i < n; i++ {
// See go/types.identicalMethods for rationale.
// Method order is not significant.
// Ignore m.Pkg().
m := t.Method(i)
hash += 3*hashString(m.Name()) + 5*h.Hash(m.Type())
}
return hash
case *types.Map:
return 9109 + 2*h.Hash(t.Key()) + 3*h.Hash(t.Elem())
case *types.Chan:
return 9127 + 2*uint32(t.Dir()) + 3*h.Hash(t.Elem())
case *types.Named:
// Not safe with a copying GC; objects may move.
return uint32(reflect.ValueOf(t.Obj()).Pointer())
case *types.Tuple:
return h.hashTuple(t)
}
panic(t)
}