cmd/cloner, cmd/viewer, util/codegen: add support for generic types and interfaces

This adds support for generic types and interfaces to our cloner and viewer codegens. It updates these packages to determine whether to make shallow or deep copies based on the type parameter constraints. Additionally, if a template parameter or an interface type has View() and Clone() methods, we'll use them for getters and the cloner of the owning structure. Updates #12736 Signed-off-by: Nick Khyl <nickk@tailscale.com>
2025-08-21 18:42:36 +00:00 · 2024-07-08 10:11:00 -05:00
parent b7c3cfe049
commit fc28c8e7f3
9 changed files with 1039 additions and 114 deletions
--- a/cmd/viewer/tests/tests_view.go
+++ b/cmd/viewer/tests/tests_view.go
@@ -10,10 +10,11 @@ import (
 	"errors"
 	"net/netip"

+	"golang.org/x/exp/constraints"
 	"tailscale.com/types/views"
 )

-//go:generate go run tailscale.com/cmd/cloner  -clonefunc=false -type=StructWithPtrs,StructWithoutPtrs,Map,StructWithSlices,OnlyGetClone,StructWithEmbedded
+//go:generate go run tailscale.com/cmd/cloner  -clonefunc=false -type=StructWithPtrs,StructWithoutPtrs,Map,StructWithSlices,OnlyGetClone,StructWithEmbedded,GenericIntStruct,GenericNoPtrsStruct,GenericCloneableStruct

 // View returns a readonly view of StructWithPtrs.
 func (p *StructWithPtrs) View() StructWithPtrsView {
@@ -221,15 +222,15 @@ func (v MapView) SlicesWithoutPtrs() views.MapFn[string, []*StructWithoutPtrs, v
 func (v MapView) StructWithoutPtrKey() views.Map[StructWithoutPtrs, int] {
 	return views.MapOf(v.ж.StructWithoutPtrKey)
 }
-func (v MapView) SliceIntPtr() map[string][]*int           { panic("unsupported") }
-func (v MapView) PointerKey() map[*string]int              { panic("unsupported") }
-func (v MapView) StructWithPtrKey() map[StructWithPtrs]int { panic("unsupported") }

 func (v MapView) StructWithPtr() views.MapFn[string, StructWithPtrs, StructWithPtrsView] {
 	return views.MapFnOf(v.ж.StructWithPtr, func(t StructWithPtrs) StructWithPtrsView {
 		return t.View()
 	})
 }
+func (v MapView) SliceIntPtr() map[string][]*int           { panic("unsupported") }
+func (v MapView) PointerKey() map[*string]int              { panic("unsupported") }
+func (v MapView) StructWithPtrKey() map[StructWithPtrs]int { panic("unsupported") }

 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
 var _MapViewNeedsRegeneration = Map(struct {
@@ -241,10 +242,10 @@ var _MapViewNeedsRegeneration = Map(struct {
 	SlicesWithPtrs      map[string][]*StructWithPtrs
 	SlicesWithoutPtrs   map[string][]*StructWithoutPtrs
 	StructWithoutPtrKey map[StructWithoutPtrs]int
+	StructWithPtr       map[string]StructWithPtrs
 	SliceIntPtr         map[string][]*int
 	PointerKey          map[*string]int
 	StructWithPtrKey    map[StructWithPtrs]int
-	StructWithPtr       map[string]StructWithPtrs
 }{})

 // View returns a readonly view of StructWithSlices.
@@ -301,24 +302,24 @@ func (v StructWithSlicesView) ValuePointers() views.SliceView[*StructWithoutPtrs
 func (v StructWithSlicesView) StructPointers() views.SliceView[*StructWithPtrs, StructWithPtrsView] {
 	return views.SliceOfViews[*StructWithPtrs, StructWithPtrsView](v.ж.StructPointers)
 }
-func (v StructWithSlicesView) Structs() StructWithPtrs    { panic("unsupported") }
-func (v StructWithSlicesView) Ints() *int                 { panic("unsupported") }
 func (v StructWithSlicesView) Slice() views.Slice[string] { return views.SliceOf(v.ж.Slice) }
 func (v StructWithSlicesView) Prefixes() views.Slice[netip.Prefix] {
 	return views.SliceOf(v.ж.Prefixes)
 }
 func (v StructWithSlicesView) Data() views.ByteSlice[[]byte] { return views.ByteSliceOf(v.ж.Data) }
+func (v StructWithSlicesView) Structs() StructWithPtrs       { panic("unsupported") }
+func (v StructWithSlicesView) Ints() *int                    { panic("unsupported") }

 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
 var _StructWithSlicesViewNeedsRegeneration = StructWithSlices(struct {
 	Values         []StructWithoutPtrs
 	ValuePointers  []*StructWithoutPtrs
 	StructPointers []*StructWithPtrs
-	Structs        []StructWithPtrs
-	Ints           []*int
 	Slice          []string
 	Prefixes       []netip.Prefix
 	Data           []byte
+	Structs        []StructWithPtrs
+	Ints           []*int
 }{})

 // View returns a readonly view of StructWithEmbedded.
@@ -376,3 +377,230 @@ var _StructWithEmbeddedViewNeedsRegeneration = StructWithEmbedded(struct {
 	A *StructWithPtrs
 	StructWithSlices
 }{})
+
+// View returns a readonly view of GenericIntStruct.
+func (p *GenericIntStruct[T]) View() GenericIntStructView[T] {
+	return GenericIntStructView[T]{ж: p}
+}
+
+// GenericIntStructView[T] provides a read-only view over GenericIntStruct[T].
+//
+// Its methods should only be called if `Valid()` returns true.
+type GenericIntStructView[T constraints.Integer] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *GenericIntStruct[T]
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v GenericIntStructView[T]) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v GenericIntStructView[T]) AsStruct() *GenericIntStruct[T] {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v GenericIntStructView[T]) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *GenericIntStructView[T]) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x GenericIntStruct[T]
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v GenericIntStructView[T]) Value() T { return v.ж.Value }
+func (v GenericIntStructView[T]) Pointer() *T {
+	if v.ж.Pointer == nil {
+		return nil
+	}
+	x := *v.ж.Pointer
+	return &x
+}
+
+func (v GenericIntStructView[T]) Slice() views.Slice[T] { return views.SliceOf(v.ж.Slice) }
+
+func (v GenericIntStructView[T]) Map() views.Map[string, T]  { return views.MapOf(v.ж.Map) }
+func (v GenericIntStructView[T]) PtrSlice() *T               { panic("unsupported") }
+func (v GenericIntStructView[T]) PtrKeyMap() map[*T]string   { panic("unsupported") }
+func (v GenericIntStructView[T]) PtrValueMap() map[string]*T { panic("unsupported") }
+func (v GenericIntStructView[T]) SliceMap() map[string][]T   { panic("unsupported") }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericIntStructViewNeedsRegeneration[T constraints.Integer](GenericIntStruct[T]) {
+	_GenericIntStructViewNeedsRegeneration(struct {
+		Value       T
+		Pointer     *T
+		Slice       []T
+		Map         map[string]T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// View returns a readonly view of GenericNoPtrsStruct.
+func (p *GenericNoPtrsStruct[T]) View() GenericNoPtrsStructView[T] {
+	return GenericNoPtrsStructView[T]{ж: p}
+}
+
+// GenericNoPtrsStructView[T] provides a read-only view over GenericNoPtrsStruct[T].
+//
+// Its methods should only be called if `Valid()` returns true.
+type GenericNoPtrsStructView[T StructWithoutPtrs | netip.Prefix | BasicType] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *GenericNoPtrsStruct[T]
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v GenericNoPtrsStructView[T]) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v GenericNoPtrsStructView[T]) AsStruct() *GenericNoPtrsStruct[T] {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v GenericNoPtrsStructView[T]) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *GenericNoPtrsStructView[T]) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x GenericNoPtrsStruct[T]
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v GenericNoPtrsStructView[T]) Value() T { return v.ж.Value }
+func (v GenericNoPtrsStructView[T]) Pointer() *T {
+	if v.ж.Pointer == nil {
+		return nil
+	}
+	x := *v.ж.Pointer
+	return &x
+}
+
+func (v GenericNoPtrsStructView[T]) Slice() views.Slice[T] { return views.SliceOf(v.ж.Slice) }
+
+func (v GenericNoPtrsStructView[T]) Map() views.Map[string, T]  { return views.MapOf(v.ж.Map) }
+func (v GenericNoPtrsStructView[T]) PtrSlice() *T               { panic("unsupported") }
+func (v GenericNoPtrsStructView[T]) PtrKeyMap() map[*T]string   { panic("unsupported") }
+func (v GenericNoPtrsStructView[T]) PtrValueMap() map[string]*T { panic("unsupported") }
+func (v GenericNoPtrsStructView[T]) SliceMap() map[string][]T   { panic("unsupported") }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericNoPtrsStructViewNeedsRegeneration[T StructWithoutPtrs | netip.Prefix | BasicType](GenericNoPtrsStruct[T]) {
+	_GenericNoPtrsStructViewNeedsRegeneration(struct {
+		Value       T
+		Pointer     *T
+		Slice       []T
+		Map         map[string]T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// View returns a readonly view of GenericCloneableStruct.
+func (p *GenericCloneableStruct[T, V]) View() GenericCloneableStructView[T, V] {
+	return GenericCloneableStructView[T, V]{ж: p}
+}
+
+// GenericCloneableStructView[T, V] provides a read-only view over GenericCloneableStruct[T, V].
+//
+// Its methods should only be called if `Valid()` returns true.
+type GenericCloneableStructView[T views.ViewCloner[T, V], V views.StructView[T]] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *GenericCloneableStruct[T, V]
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v GenericCloneableStructView[T, V]) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v GenericCloneableStructView[T, V]) AsStruct() *GenericCloneableStruct[T, V] {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v GenericCloneableStructView[T, V]) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *GenericCloneableStructView[T, V]) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x GenericCloneableStruct[T, V]
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v GenericCloneableStructView[T, V]) Value() V { return v.ж.Value.View() }
+func (v GenericCloneableStructView[T, V]) Slice() views.SliceView[T, V] {
+	return views.SliceOfViews[T, V](v.ж.Slice)
+}
+
+func (v GenericCloneableStructView[T, V]) Map() views.MapFn[string, T, V] {
+	return views.MapFnOf(v.ж.Map, func(t T) V {
+		return t.View()
+	})
+}
+func (v GenericCloneableStructView[T, V]) Pointer() map[string]T      { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) PtrSlice() *T               { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) PtrKeyMap() map[*T]string   { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) PtrValueMap() map[string]*T { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) SliceMap() map[string][]T   { panic("unsupported") }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericCloneableStructViewNeedsRegeneration[T views.ViewCloner[T, V], V views.StructView[T]](GenericCloneableStruct[T, V]) {
+	_GenericCloneableStructViewNeedsRegeneration(struct {
+		Value       T
+		Slice       []T
+		Map         map[string]T
+		Pointer     *T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}