func FindImplentations(i *types.Interface, pkg *types.Package) []string {
var names []string
scope := pkg.Scope()
allNames := scope.Names()
for _, name := range allNames {
obj := scope.Lookup(name)
if typeName, ok := obj.(*types.TypeName); ok {
if types.Implements(typeName.Type(), i) {
names = append(names, typeName.Name())
} else {
println(typeName.Name(), "cannot be an ensurer")
println(types.NewMethodSet(typeName.Type()).String())
}
}
}
return names
}
// matchArgTypeInternal is the internal version of matchArgType. It carries a map
// remembering what types are in progress so we don't recur when faced with recursive
// types or mutually recursive types.
func (f *File) matchArgTypeInternal(t printfArgType, typ types.Type, arg ast.Expr, inProgress map[types.Type]bool) bool {
// %v, %T accept any argument type.
if t == anyType {
return true
}
if typ == nil {
// external call
typ = f.pkg.types[arg]
if typ == nil {
return true // probably a type check problem
}
}
// If the type implements fmt.Formatter, we have nothing to check.
// But (see issue 6259) that's not easy to verify, so instead we see
// if its method set contains a Format function. We could do better,
// even now, but we don't need to be 100% accurate. Wait for 6259 to
// be fixed instead. TODO.
if hasMethod(typ, "Format") {
return true
}
// If we can use a string, might arg (dynamically) implement the Stringer or Error interface?
if t&argString != 0 {
if types.Implements(typ, errorType, false) || types.Implements(typ, stringerType, false) {
return true
}
}
typ = typ.Underlying()
if inProgress[typ] {
// We're already looking at this type. The call that started it will take care of it.
return true
}
inProgress[typ] = true
switch typ := typ.(type) {
case *types.Signature:
return t&argPointer != 0
case *types.Map:
// Recur: map[int]int matches %d.
return t&argPointer != 0 ||
(f.matchArgTypeInternal(t, typ.Key(), arg, inProgress) && f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress))
case *types.Chan:
return t&argPointer != 0
case *types.Array:
// Same as slice.
if types.IsIdentical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
return true // %s matches []byte
}
// Recur: []int matches %d.
return t&argPointer != 0 || f.matchArgTypeInternal(t, typ.Elem().Underlying(), arg, inProgress)
case *types.Slice:
// Same as array.
if types.IsIdentical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
return true // %s matches []byte
}
// Recur: []int matches %d. But watch out for
// type T []T
// If the element is a pointer type (type T[]*T), it's handled fine by the Pointer case below.
return t&argPointer != 0 || f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress)
case *types.Pointer:
// Ugly, but dealing with an edge case: a known pointer to an invalid type,
// probably something from a failed import.
if typ.Elem().String() == "invalid type" {
if *verbose {
f.Warnf(arg.Pos(), "printf argument %v is pointer to invalid or unknown type", f.gofmt(arg))
}
return true // special case
}
// If it's actually a pointer with %p, it prints as one.
if t == argPointer {
return true
}
// If it's pointer to struct, that's equivalent in our analysis to whether we can print the struct.
if str, ok := typ.Elem().Underlying().(*types.Struct); ok {
return f.matchStructArgType(t, str, arg, inProgress)
}
// The rest can print with %p as pointers, or as integers with %x etc.
return t&(argInt|argPointer) != 0
case *types.Struct:
return f.matchStructArgType(t, typ, arg, inProgress)
case *types.Interface:
// If the static type of the argument is empty interface, there's little we can do.
// Example:
// func f(x interface{}) { fmt.Printf("%s", x) }
// Whether x is valid for %s depends on the type of the argument to f. One day
// we will be able to do better. For now, we assume that empty interface is OK
// but non-empty interfaces, with Stringer and Error handled above, are errors.
return typ.NumMethods() == 0
case *types.Basic:
switch typ.Kind() {
case types.UntypedBool,
types.Bool:
return t&argBool != 0
case types.UntypedInt,
types.Int,
types.Int8,
types.Int16,
types.Int32,
types.Int64,
types.Uint,
types.Uint8,
types.Uint16,
types.Uint32,
types.Uint64,
types.Uintptr:
return t&argInt != 0
case types.UntypedFloat,
types.Float32,
types.Float64:
return t&argFloat != 0
case types.UntypedComplex,
types.Complex64,
types.Complex128:
return t&argComplex != 0
case types.UntypedString,
types.String:
return t&argString != 0
case types.UnsafePointer:
return t&(argPointer|argInt) != 0
case types.UntypedRune:
return t&(argInt|argRune) != 0
case types.UntypedNil:
return t&argPointer != 0 // TODO?
case types.Invalid:
if *verbose {
f.Warnf(arg.Pos(), "printf argument %v has invalid or unknown type", f.gofmt(arg))
}
return true // Probably a type check problem.
}
panic("unreachable")
}
return false
}