| // Copyright 2018 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package objectpath defines a naming scheme for types.Objects |
| // (that is, named entities in Go programs) relative to their enclosing |
| // package. |
| // |
| // Type-checker objects are canonical, so they are usually identified by |
| // their address in memory (a pointer), but a pointer has meaning only |
| // within one address space. By contrast, objectpath names allow the |
| // identity of an object to be sent from one program to another, |
| // establishing a correspondence between types.Object variables that are |
| // distinct but logically equivalent. |
| // |
| // A single object may have multiple paths. In this example, |
| // |
| // type A struct{ X int } |
| // type B A |
| // |
| // the field X has two paths due to its membership of both A and B. |
| // The For(obj) function always returns one of these paths, arbitrarily |
| // but consistently. |
| package objectpath |
| |
| import ( |
| "fmt" |
| "go/types" |
| "sort" |
| "strconv" |
| "strings" |
| |
| "golang.org/x/tools/internal/typeparams" |
| |
| _ "unsafe" // for go:linkname |
| ) |
| |
| // A Path is an opaque name that identifies a types.Object |
| // relative to its package. Conceptually, the name consists of a |
| // sequence of destructuring operations applied to the package scope |
| // to obtain the original object. |
| // The name does not include the package itself. |
| type Path string |
| |
| // Encoding |
| // |
| // An object path is a textual and (with training) human-readable encoding |
| // of a sequence of destructuring operators, starting from a types.Package. |
| // The sequences represent a path through the package/object/type graph. |
| // We classify these operators by their type: |
| // |
| // PO package->object Package.Scope.Lookup |
| // OT object->type Object.Type |
| // TT type->type Type.{Elem,Key,Params,Results,Underlying} [EKPRU] |
| // TO type->object Type.{At,Field,Method,Obj} [AFMO] |
| // |
| // All valid paths start with a package and end at an object |
| // and thus may be defined by the regular language: |
| // |
| // objectpath = PO (OT TT* TO)* |
| // |
| // The concrete encoding follows directly: |
| // - The only PO operator is Package.Scope.Lookup, which requires an identifier. |
| // - The only OT operator is Object.Type, |
| // which we encode as '.' because dot cannot appear in an identifier. |
| // - The TT operators are encoded as [EKPRUTC]; |
| // one of these (TypeParam) requires an integer operand, |
| // which is encoded as a string of decimal digits. |
| // - The TO operators are encoded as [AFMO]; |
| // three of these (At,Field,Method) require an integer operand, |
| // which is encoded as a string of decimal digits. |
| // These indices are stable across different representations |
| // of the same package, even source and export data. |
| // The indices used are implementation specific and may not correspond to |
| // the argument to the go/types function. |
| // |
| // In the example below, |
| // |
| // package p |
| // |
| // type T interface { |
| // f() (a string, b struct{ X int }) |
| // } |
| // |
| // field X has the path "T.UM0.RA1.F0", |
| // representing the following sequence of operations: |
| // |
| // p.Lookup("T") T |
| // .Type().Underlying().Method(0). f |
| // .Type().Results().At(1) b |
| // .Type().Field(0) X |
| // |
| // The encoding is not maximally compact---every R or P is |
| // followed by an A, for example---but this simplifies the |
| // encoder and decoder. |
| const ( |
| // object->type operators |
| opType = '.' // .Type() (Object) |
| |
| // type->type operators |
| opElem = 'E' // .Elem() (Pointer, Slice, Array, Chan, Map) |
| opKey = 'K' // .Key() (Map) |
| opParams = 'P' // .Params() (Signature) |
| opResults = 'R' // .Results() (Signature) |
| opUnderlying = 'U' // .Underlying() (Named) |
| opTypeParam = 'T' // .TypeParams.At(i) (Named, Signature) |
| opConstraint = 'C' // .Constraint() (TypeParam) |
| |
| // type->object operators |
| opAt = 'A' // .At(i) (Tuple) |
| opField = 'F' // .Field(i) (Struct) |
| opMethod = 'M' // .Method(i) (Named or Interface; not Struct: "promoted" names are ignored) |
| opObj = 'O' // .Obj() (Named, TypeParam) |
| ) |
| |
| // For is equivalent to new(Encoder).For(obj). |
| // |
| // It may be more efficient to reuse a single Encoder across several calls. |
| func For(obj types.Object) (Path, error) { |
| return new(Encoder).For(obj) |
| } |
| |
| // An Encoder amortizes the cost of encoding the paths of multiple objects. |
| // The zero value of an Encoder is ready to use. |
| type Encoder struct { |
| scopeNamesMemo map[*types.Scope][]string // memoization of Scope.Names() |
| namedMethodsMemo map[*types.Named][]*types.Func // memoization of namedMethods() |
| } |
| |
| // For returns the path to an object relative to its package, |
| // or an error if the object is not accessible from the package's Scope. |
| // |
| // The For function guarantees to return a path only for the following objects: |
| // - package-level types |
| // - exported package-level non-types |
| // - methods |
| // - parameter and result variables |
| // - struct fields |
| // These objects are sufficient to define the API of their package. |
| // The objects described by a package's export data are drawn from this set. |
| // |
| // For does not return a path for predeclared names, imported package |
| // names, local names, and unexported package-level names (except |
| // types). |
| // |
| // Example: given this definition, |
| // |
| // package p |
| // |
| // type T interface { |
| // f() (a string, b struct{ X int }) |
| // } |
| // |
| // For(X) would return a path that denotes the following sequence of operations: |
| // |
| // p.Scope().Lookup("T") (TypeName T) |
| // .Type().Underlying().Method(0). (method Func f) |
| // .Type().Results().At(1) (field Var b) |
| // .Type().Field(0) (field Var X) |
| // |
| // where p is the package (*types.Package) to which X belongs. |
| func (enc *Encoder) For(obj types.Object) (Path, error) { |
| pkg := obj.Pkg() |
| |
| // This table lists the cases of interest. |
| // |
| // Object Action |
| // ------ ------ |
| // nil reject |
| // builtin reject |
| // pkgname reject |
| // label reject |
| // var |
| // package-level accept |
| // func param/result accept |
| // local reject |
| // struct field accept |
| // const |
| // package-level accept |
| // local reject |
| // func |
| // package-level accept |
| // init functions reject |
| // concrete method accept |
| // interface method accept |
| // type |
| // package-level accept |
| // local reject |
| // |
| // The only accessible package-level objects are members of pkg itself. |
| // |
| // The cases are handled in four steps: |
| // |
| // 1. reject nil and builtin |
| // 2. accept package-level objects |
| // 3. reject obviously invalid objects |
| // 4. search the API for the path to the param/result/field/method. |
| |
| // 1. reference to nil or builtin? |
| if pkg == nil { |
| return "", fmt.Errorf("predeclared %s has no path", obj) |
| } |
| scope := pkg.Scope() |
| |
| // 2. package-level object? |
| if scope.Lookup(obj.Name()) == obj { |
| // Only exported objects (and non-exported types) have a path. |
| // Non-exported types may be referenced by other objects. |
| if _, ok := obj.(*types.TypeName); !ok && !obj.Exported() { |
| return "", fmt.Errorf("no path for non-exported %v", obj) |
| } |
| return Path(obj.Name()), nil |
| } |
| |
| // 3. Not a package-level object. |
| // Reject obviously non-viable cases. |
| switch obj := obj.(type) { |
| case *types.TypeName: |
| if _, ok := obj.Type().(*typeparams.TypeParam); !ok { |
| // With the exception of type parameters, only package-level type names |
| // have a path. |
| return "", fmt.Errorf("no path for %v", obj) |
| } |
| case *types.Const, // Only package-level constants have a path. |
| *types.Label, // Labels are function-local. |
| *types.PkgName: // PkgNames are file-local. |
| return "", fmt.Errorf("no path for %v", obj) |
| |
| case *types.Var: |
| // Could be: |
| // - a field (obj.IsField()) |
| // - a func parameter or result |
| // - a local var. |
| // Sadly there is no way to distinguish |
| // a param/result from a local |
| // so we must proceed to the find. |
| |
| case *types.Func: |
| // A func, if not package-level, must be a method. |
| if recv := obj.Type().(*types.Signature).Recv(); recv == nil { |
| return "", fmt.Errorf("func is not a method: %v", obj) |
| } |
| |
| if path, ok := enc.concreteMethod(obj); ok { |
| // Fast path for concrete methods that avoids looping over scope. |
| return path, nil |
| } |
| |
| default: |
| panic(obj) |
| } |
| |
| // 4. Search the API for the path to the var (field/param/result) or method. |
| |
| // First inspect package-level named types. |
| // In the presence of path aliases, these give |
| // the best paths because non-types may |
| // refer to types, but not the reverse. |
| empty := make([]byte, 0, 48) // initial space |
| names := enc.scopeNames(scope) |
| for _, name := range names { |
| o := scope.Lookup(name) |
| tname, ok := o.(*types.TypeName) |
| if !ok { |
| continue // handle non-types in second pass |
| } |
| |
| path := append(empty, name...) |
| path = append(path, opType) |
| |
| T := o.Type() |
| |
| if tname.IsAlias() { |
| // type alias |
| if r := find(obj, T, path, nil); r != nil { |
| return Path(r), nil |
| } |
| } else { |
| if named, _ := T.(*types.Named); named != nil { |
| if r := findTypeParam(obj, typeparams.ForNamed(named), path, nil); r != nil { |
| // generic named type |
| return Path(r), nil |
| } |
| } |
| // defined (named) type |
| if r := find(obj, T.Underlying(), append(path, opUnderlying), nil); r != nil { |
| return Path(r), nil |
| } |
| } |
| } |
| |
| // Then inspect everything else: |
| // non-types, and declared methods of defined types. |
| for _, name := range names { |
| o := scope.Lookup(name) |
| path := append(empty, name...) |
| if _, ok := o.(*types.TypeName); !ok { |
| if o.Exported() { |
| // exported non-type (const, var, func) |
| if r := find(obj, o.Type(), append(path, opType), nil); r != nil { |
| return Path(r), nil |
| } |
| } |
| continue |
| } |
| |
| // Inspect declared methods of defined types. |
| if T, ok := o.Type().(*types.Named); ok { |
| path = append(path, opType) |
| // Note that method index here is always with respect |
| // to canonical ordering of methods, regardless of how |
| // they appear in the underlying type. |
| for i, m := range enc.namedMethods(T) { |
| path2 := appendOpArg(path, opMethod, i) |
| if m == obj { |
| return Path(path2), nil // found declared method |
| } |
| if r := find(obj, m.Type(), append(path2, opType), nil); r != nil { |
| return Path(r), nil |
| } |
| } |
| } |
| } |
| |
| return "", fmt.Errorf("can't find path for %v in %s", obj, pkg.Path()) |
| } |
| |
| func appendOpArg(path []byte, op byte, arg int) []byte { |
| path = append(path, op) |
| path = strconv.AppendInt(path, int64(arg), 10) |
| return path |
| } |
| |
| // concreteMethod returns the path for meth, which must have a non-nil receiver. |
| // The second return value indicates success and may be false if the method is |
| // an interface method or if it is an instantiated method. |
| // |
| // This function is just an optimization that avoids the general scope walking |
| // approach. You are expected to fall back to the general approach if this |
| // function fails. |
| func (enc *Encoder) concreteMethod(meth *types.Func) (Path, bool) { |
| // Concrete methods can only be declared on package-scoped named types. For |
| // that reason we can skip the expensive walk over the package scope: the |
| // path will always be package -> named type -> method. We can trivially get |
| // the type name from the receiver, and only have to look over the type's |
| // methods to find the method index. |
| // |
| // Methods on generic types require special consideration, however. Consider |
| // the following package: |
| // |
| // L1: type S[T any] struct{} |
| // L2: func (recv S[A]) Foo() { recv.Bar() } |
| // L3: func (recv S[B]) Bar() { } |
| // L4: type Alias = S[int] |
| // L5: func _[T any]() { var s S[int]; s.Foo() } |
| // |
| // The receivers of methods on generic types are instantiations. L2 and L3 |
| // instantiate S with the type-parameters A and B, which are scoped to the |
| // respective methods. L4 and L5 each instantiate S with int. Each of these |
| // instantiations has its own method set, full of methods (and thus objects) |
| // with receivers whose types are the respective instantiations. In other |
| // words, we have |
| // |
| // S[A].Foo, S[A].Bar |
| // S[B].Foo, S[B].Bar |
| // S[int].Foo, S[int].Bar |
| // |
| // We may thus be trying to produce object paths for any of these objects. |
| // |
| // S[A].Foo and S[B].Bar are the origin methods, and their paths are S.Foo |
| // and S.Bar, which are the paths that this function naturally produces. |
| // |
| // S[A].Bar, S[B].Foo, and both methods on S[int] are instantiations that |
| // don't correspond to the origin methods. For S[int], this is significant. |
| // The most precise object path for S[int].Foo, for example, is Alias.Foo, |
| // not S.Foo. Our function, however, would produce S.Foo, which would |
| // resolve to a different object. |
| // |
| // For S[A].Bar and S[B].Foo it could be argued that S.Bar and S.Foo are |
| // still the correct paths, since only the origin methods have meaningful |
| // paths. But this is likely only true for trivial cases and has edge cases. |
| // Since this function is only an optimization, we err on the side of giving |
| // up, deferring to the slower but definitely correct algorithm. Most users |
| // of objectpath will only be giving us origin methods, anyway, as referring |
| // to instantiated methods is usually not useful. |
| |
| if typeparams.OriginMethod(meth) != meth { |
| return "", false |
| } |
| |
| recvT := meth.Type().(*types.Signature).Recv().Type() |
| if ptr, ok := recvT.(*types.Pointer); ok { |
| recvT = ptr.Elem() |
| } |
| |
| named, ok := recvT.(*types.Named) |
| if !ok { |
| return "", false |
| } |
| |
| if types.IsInterface(named) { |
| // Named interfaces don't have to be package-scoped |
| // |
| // TODO(dominikh): opt: if scope.Lookup(name) == named, then we can apply this optimization to interface |
| // methods, too, I think. |
| return "", false |
| } |
| |
| // Preallocate space for the name, opType, opMethod, and some digits. |
| name := named.Obj().Name() |
| path := make([]byte, 0, len(name)+8) |
| path = append(path, name...) |
| path = append(path, opType) |
| for i, m := range enc.namedMethods(named) { |
| if m == meth { |
| path = appendOpArg(path, opMethod, i) |
| return Path(path), true |
| } |
| } |
| |
| panic(fmt.Sprintf("couldn't find method %s on type %s", meth, named)) |
| } |
| |
| // find finds obj within type T, returning the path to it, or nil if not found. |
| // |
| // The seen map is used to short circuit cycles through type parameters. If |
| // nil, it will be allocated as necessary. |
| func find(obj types.Object, T types.Type, path []byte, seen map[*types.TypeName]bool) []byte { |
| switch T := T.(type) { |
| case *types.Basic, *types.Named: |
| // Named types belonging to pkg were handled already, |
| // so T must belong to another package. No path. |
| return nil |
| case *types.Pointer: |
| return find(obj, T.Elem(), append(path, opElem), seen) |
| case *types.Slice: |
| return find(obj, T.Elem(), append(path, opElem), seen) |
| case *types.Array: |
| return find(obj, T.Elem(), append(path, opElem), seen) |
| case *types.Chan: |
| return find(obj, T.Elem(), append(path, opElem), seen) |
| case *types.Map: |
| if r := find(obj, T.Key(), append(path, opKey), seen); r != nil { |
| return r |
| } |
| return find(obj, T.Elem(), append(path, opElem), seen) |
| case *types.Signature: |
| if r := findTypeParam(obj, typeparams.ForSignature(T), path, seen); r != nil { |
| return r |
| } |
| if r := find(obj, T.Params(), append(path, opParams), seen); r != nil { |
| return r |
| } |
| return find(obj, T.Results(), append(path, opResults), seen) |
| case *types.Struct: |
| for i := 0; i < T.NumFields(); i++ { |
| fld := T.Field(i) |
| path2 := appendOpArg(path, opField, i) |
| if fld == obj { |
| return path2 // found field var |
| } |
| if r := find(obj, fld.Type(), append(path2, opType), seen); r != nil { |
| return r |
| } |
| } |
| return nil |
| case *types.Tuple: |
| for i := 0; i < T.Len(); i++ { |
| v := T.At(i) |
| path2 := appendOpArg(path, opAt, i) |
| if v == obj { |
| return path2 // found param/result var |
| } |
| if r := find(obj, v.Type(), append(path2, opType), seen); r != nil { |
| return r |
| } |
| } |
| return nil |
| case *types.Interface: |
| for i := 0; i < T.NumMethods(); i++ { |
| m := T.Method(i) |
| path2 := appendOpArg(path, opMethod, i) |
| if m == obj { |
| return path2 // found interface method |
| } |
| if r := find(obj, m.Type(), append(path2, opType), seen); r != nil { |
| return r |
| } |
| } |
| return nil |
| case *typeparams.TypeParam: |
| name := T.Obj() |
| if name == obj { |
| return append(path, opObj) |
| } |
| if seen[name] { |
| return nil |
| } |
| if seen == nil { |
| seen = make(map[*types.TypeName]bool) |
| } |
| seen[name] = true |
| if r := find(obj, T.Constraint(), append(path, opConstraint), seen); r != nil { |
| return r |
| } |
| return nil |
| } |
| panic(T) |
| } |
| |
| func findTypeParam(obj types.Object, list *typeparams.TypeParamList, path []byte, seen map[*types.TypeName]bool) []byte { |
| for i := 0; i < list.Len(); i++ { |
| tparam := list.At(i) |
| path2 := appendOpArg(path, opTypeParam, i) |
| if r := find(obj, tparam, path2, seen); r != nil { |
| return r |
| } |
| } |
| return nil |
| } |
| |
| // Object returns the object denoted by path p within the package pkg. |
| func Object(pkg *types.Package, p Path) (types.Object, error) { |
| if p == "" { |
| return nil, fmt.Errorf("empty path") |
| } |
| |
| pathstr := string(p) |
| var pkgobj, suffix string |
| if dot := strings.IndexByte(pathstr, opType); dot < 0 { |
| pkgobj = pathstr |
| } else { |
| pkgobj = pathstr[:dot] |
| suffix = pathstr[dot:] // suffix starts with "." |
| } |
| |
| obj := pkg.Scope().Lookup(pkgobj) |
| if obj == nil { |
| return nil, fmt.Errorf("package %s does not contain %q", pkg.Path(), pkgobj) |
| } |
| |
| // abstraction of *types.{Pointer,Slice,Array,Chan,Map} |
| type hasElem interface { |
| Elem() types.Type |
| } |
| // abstraction of *types.{Named,Signature} |
| type hasTypeParams interface { |
| TypeParams() *typeparams.TypeParamList |
| } |
| // abstraction of *types.{Named,TypeParam} |
| type hasObj interface { |
| Obj() *types.TypeName |
| } |
| |
| // The loop state is the pair (t, obj), |
| // exactly one of which is non-nil, initially obj. |
| // All suffixes start with '.' (the only object->type operation), |
| // followed by optional type->type operations, |
| // then a type->object operation. |
| // The cycle then repeats. |
| var t types.Type |
| for suffix != "" { |
| code := suffix[0] |
| suffix = suffix[1:] |
| |
| // Codes [AFM] have an integer operand. |
| var index int |
| switch code { |
| case opAt, opField, opMethod, opTypeParam: |
| rest := strings.TrimLeft(suffix, "0123456789") |
| numerals := suffix[:len(suffix)-len(rest)] |
| suffix = rest |
| i, err := strconv.Atoi(numerals) |
| if err != nil { |
| return nil, fmt.Errorf("invalid path: bad numeric operand %q for code %q", numerals, code) |
| } |
| index = int(i) |
| case opObj: |
| // no operand |
| default: |
| // The suffix must end with a type->object operation. |
| if suffix == "" { |
| return nil, fmt.Errorf("invalid path: ends with %q, want [AFMO]", code) |
| } |
| } |
| |
| if code == opType { |
| if t != nil { |
| return nil, fmt.Errorf("invalid path: unexpected %q in type context", opType) |
| } |
| t = obj.Type() |
| obj = nil |
| continue |
| } |
| |
| if t == nil { |
| return nil, fmt.Errorf("invalid path: code %q in object context", code) |
| } |
| |
| // Inv: t != nil, obj == nil |
| |
| switch code { |
| case opElem: |
| hasElem, ok := t.(hasElem) // Pointer, Slice, Array, Chan, Map |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want pointer, slice, array, chan or map)", code, t, t) |
| } |
| t = hasElem.Elem() |
| |
| case opKey: |
| mapType, ok := t.(*types.Map) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want map)", code, t, t) |
| } |
| t = mapType.Key() |
| |
| case opParams: |
| sig, ok := t.(*types.Signature) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want signature)", code, t, t) |
| } |
| t = sig.Params() |
| |
| case opResults: |
| sig, ok := t.(*types.Signature) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want signature)", code, t, t) |
| } |
| t = sig.Results() |
| |
| case opUnderlying: |
| named, ok := t.(*types.Named) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want named)", code, t, t) |
| } |
| t = named.Underlying() |
| |
| case opTypeParam: |
| hasTypeParams, ok := t.(hasTypeParams) // Named, Signature |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want named or signature)", code, t, t) |
| } |
| tparams := hasTypeParams.TypeParams() |
| if n := tparams.Len(); index >= n { |
| return nil, fmt.Errorf("tuple index %d out of range [0-%d)", index, n) |
| } |
| t = tparams.At(index) |
| |
| case opConstraint: |
| tparam, ok := t.(*typeparams.TypeParam) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want type parameter)", code, t, t) |
| } |
| t = tparam.Constraint() |
| |
| case opAt: |
| tuple, ok := t.(*types.Tuple) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want tuple)", code, t, t) |
| } |
| if n := tuple.Len(); index >= n { |
| return nil, fmt.Errorf("tuple index %d out of range [0-%d)", index, n) |
| } |
| obj = tuple.At(index) |
| t = nil |
| |
| case opField: |
| structType, ok := t.(*types.Struct) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want struct)", code, t, t) |
| } |
| if n := structType.NumFields(); index >= n { |
| return nil, fmt.Errorf("field index %d out of range [0-%d)", index, n) |
| } |
| obj = structType.Field(index) |
| t = nil |
| |
| case opMethod: |
| switch t := t.(type) { |
| case *types.Interface: |
| if index >= t.NumMethods() { |
| return nil, fmt.Errorf("method index %d out of range [0-%d)", index, t.NumMethods()) |
| } |
| obj = t.Method(index) // Id-ordered |
| |
| case *types.Named: |
| methods := namedMethods(t) // (unmemoized) |
| if index >= len(methods) { |
| return nil, fmt.Errorf("method index %d out of range [0-%d)", index, len(methods)) |
| } |
| obj = methods[index] // Id-ordered |
| |
| default: |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want interface or named)", code, t, t) |
| } |
| t = nil |
| |
| case opObj: |
| hasObj, ok := t.(hasObj) |
| if !ok { |
| return nil, fmt.Errorf("cannot apply %q to %s (got %T, want named or type param)", code, t, t) |
| } |
| obj = hasObj.Obj() |
| t = nil |
| |
| default: |
| return nil, fmt.Errorf("invalid path: unknown code %q", code) |
| } |
| } |
| |
| if obj.Pkg() != pkg { |
| return nil, fmt.Errorf("path denotes %s, which belongs to a different package", obj) |
| } |
| |
| return obj, nil // success |
| } |
| |
| // namedMethods returns the methods of a Named type in ascending Id order. |
| func namedMethods(named *types.Named) []*types.Func { |
| methods := make([]*types.Func, named.NumMethods()) |
| for i := range methods { |
| methods[i] = named.Method(i) |
| } |
| sort.Slice(methods, func(i, j int) bool { |
| return methods[i].Id() < methods[j].Id() |
| }) |
| return methods |
| } |
| |
| // namedMethods is a memoization of the namedMethods function. Callers must not modify the result. |
| func (enc *Encoder) namedMethods(named *types.Named) []*types.Func { |
| m := enc.namedMethodsMemo |
| if m == nil { |
| m = make(map[*types.Named][]*types.Func) |
| enc.namedMethodsMemo = m |
| } |
| methods, ok := m[named] |
| if !ok { |
| methods = namedMethods(named) // allocates and sorts |
| m[named] = methods |
| } |
| return methods |
| } |
| |
| // scopeNames is a memoization of scope.Names. Callers must not modify the result. |
| func (enc *Encoder) scopeNames(scope *types.Scope) []string { |
| m := enc.scopeNamesMemo |
| if m == nil { |
| m = make(map[*types.Scope][]string) |
| enc.scopeNamesMemo = m |
| } |
| names, ok := m[scope] |
| if !ok { |
| names = scope.Names() // allocates and sorts |
| m[scope] = names |
| } |
| return names |
| } |