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Diffstat (limited to 'vendor/sigs.k8s.io/structured-merge-diff/v4/value/valuereflect.go')
-rw-r--r-- | vendor/sigs.k8s.io/structured-merge-diff/v4/value/valuereflect.go | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/vendor/sigs.k8s.io/structured-merge-diff/v4/value/valuereflect.go b/vendor/sigs.k8s.io/structured-merge-diff/v4/value/valuereflect.go new file mode 100644 index 000000000..05e70deba --- /dev/null +++ b/vendor/sigs.k8s.io/structured-merge-diff/v4/value/valuereflect.go @@ -0,0 +1,294 @@ +/* +Copyright 2019 The Kubernetes Authors. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package value + +import ( + "encoding/base64" + "fmt" + "reflect" +) + +// NewValueReflect creates a Value backed by an "interface{}" type, +// typically an structured object in Kubernetes world that is uses reflection to expose. +// The provided "interface{}" value must be a pointer so that the value can be modified via reflection. +// The provided "interface{}" may contain structs and types that are converted to Values +// by the jsonMarshaler interface. +func NewValueReflect(value interface{}) (Value, error) { + if value == nil { + return NewValueInterface(nil), nil + } + v := reflect.ValueOf(value) + if v.Kind() != reflect.Ptr { + // The root value to reflect on must be a pointer so that map.Set() and map.Delete() operations are possible. + return nil, fmt.Errorf("value provided to NewValueReflect must be a pointer") + } + return wrapValueReflect(v, nil, nil) +} + +// wrapValueReflect wraps the provide reflect.Value as a value. If parent in the data tree is a map, parentMap +// and parentMapKey must be provided so that the returned value may be set and deleted. +func wrapValueReflect(value reflect.Value, parentMap, parentMapKey *reflect.Value) (Value, error) { + val := HeapAllocator.allocValueReflect() + return val.reuse(value, nil, parentMap, parentMapKey) +} + +// wrapValueReflect wraps the provide reflect.Value as a value, and panics if there is an error. If parent in the data +// tree is a map, parentMap and parentMapKey must be provided so that the returned value may be set and deleted. +func mustWrapValueReflect(value reflect.Value, parentMap, parentMapKey *reflect.Value) Value { + v, err := wrapValueReflect(value, parentMap, parentMapKey) + if err != nil { + panic(err) + } + return v +} + +// the value interface doesn't care about the type for value.IsNull, so we can use a constant +var nilType = reflect.TypeOf(&struct{}{}) + +// reuse replaces the value of the valueReflect. If parent in the data tree is a map, parentMap and parentMapKey +// must be provided so that the returned value may be set and deleted. +func (r *valueReflect) reuse(value reflect.Value, cacheEntry *TypeReflectCacheEntry, parentMap, parentMapKey *reflect.Value) (Value, error) { + if cacheEntry == nil { + cacheEntry = TypeReflectEntryOf(value.Type()) + } + if cacheEntry.CanConvertToUnstructured() { + u, err := cacheEntry.ToUnstructured(value) + if err != nil { + return nil, err + } + if u == nil { + value = reflect.Zero(nilType) + } else { + value = reflect.ValueOf(u) + } + } + r.Value = dereference(value) + r.ParentMap = parentMap + r.ParentMapKey = parentMapKey + r.kind = kind(r.Value) + return r, nil +} + +// mustReuse replaces the value of the valueReflect and panics if there is an error. If parent in the data tree is a +// map, parentMap and parentMapKey must be provided so that the returned value may be set and deleted. +func (r *valueReflect) mustReuse(value reflect.Value, cacheEntry *TypeReflectCacheEntry, parentMap, parentMapKey *reflect.Value) Value { + v, err := r.reuse(value, cacheEntry, parentMap, parentMapKey) + if err != nil { + panic(err) + } + return v +} + +func dereference(val reflect.Value) reflect.Value { + kind := val.Kind() + if (kind == reflect.Interface || kind == reflect.Ptr) && !safeIsNil(val) { + return val.Elem() + } + return val +} + +type valueReflect struct { + ParentMap *reflect.Value + ParentMapKey *reflect.Value + Value reflect.Value + kind reflectType +} + +func (r valueReflect) IsMap() bool { + return r.kind == mapType || r.kind == structMapType +} + +func (r valueReflect) IsList() bool { + return r.kind == listType +} + +func (r valueReflect) IsBool() bool { + return r.kind == boolType +} + +func (r valueReflect) IsInt() bool { + return r.kind == intType || r.kind == uintType +} + +func (r valueReflect) IsFloat() bool { + return r.kind == floatType +} + +func (r valueReflect) IsString() bool { + return r.kind == stringType || r.kind == byteStringType +} + +func (r valueReflect) IsNull() bool { + return r.kind == nullType +} + +type reflectType = int + +const ( + mapType = iota + structMapType + listType + intType + uintType + floatType + stringType + byteStringType + boolType + nullType +) + +func kind(v reflect.Value) reflectType { + typ := v.Type() + rk := typ.Kind() + switch rk { + case reflect.Map: + if v.IsNil() { + return nullType + } + return mapType + case reflect.Struct: + return structMapType + case reflect.Int, reflect.Int64, reflect.Int32, reflect.Int16, reflect.Int8: + return intType + case reflect.Uint, reflect.Uint32, reflect.Uint16, reflect.Uint8: + // Uint64 deliberately excluded, see valueUnstructured.Int. + return uintType + case reflect.Float64, reflect.Float32: + return floatType + case reflect.String: + return stringType + case reflect.Bool: + return boolType + case reflect.Slice: + if v.IsNil() { + return nullType + } + elemKind := typ.Elem().Kind() + if elemKind == reflect.Uint8 { + return byteStringType + } + return listType + case reflect.Chan, reflect.Func, reflect.Ptr, reflect.UnsafePointer, reflect.Interface: + if v.IsNil() { + return nullType + } + panic(fmt.Sprintf("unsupported type: %v", v.Type())) + default: + panic(fmt.Sprintf("unsupported type: %v", v.Type())) + } +} + +// TODO find a cleaner way to avoid panics from reflect.IsNil() +func safeIsNil(v reflect.Value) bool { + k := v.Kind() + switch k { + case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.UnsafePointer, reflect.Interface, reflect.Slice: + return v.IsNil() + } + return false +} + +func (r valueReflect) AsMap() Map { + return r.AsMapUsing(HeapAllocator) +} + +func (r valueReflect) AsMapUsing(a Allocator) Map { + switch r.kind { + case structMapType: + v := a.allocStructReflect() + v.valueReflect = r + return v + case mapType: + v := a.allocMapReflect() + v.valueReflect = r + return v + default: + panic("value is not a map or struct") + } +} + +func (r valueReflect) AsList() List { + return r.AsListUsing(HeapAllocator) +} + +func (r valueReflect) AsListUsing(a Allocator) List { + if r.IsList() { + v := a.allocListReflect() + v.Value = r.Value + return v + } + panic("value is not a list") +} + +func (r valueReflect) AsBool() bool { + if r.IsBool() { + return r.Value.Bool() + } + panic("value is not a bool") +} + +func (r valueReflect) AsInt() int64 { + if r.kind == intType { + return r.Value.Int() + } + if r.kind == uintType { + return int64(r.Value.Uint()) + } + + panic("value is not an int") +} + +func (r valueReflect) AsFloat() float64 { + if r.IsFloat() { + return r.Value.Float() + } + panic("value is not a float") +} + +func (r valueReflect) AsString() string { + switch r.kind { + case stringType: + return r.Value.String() + case byteStringType: + return base64.StdEncoding.EncodeToString(r.Value.Bytes()) + } + panic("value is not a string") +} + +func (r valueReflect) Unstructured() interface{} { + val := r.Value + switch { + case r.IsNull(): + return nil + case val.Kind() == reflect.Struct: + return structReflect{r}.Unstructured() + case val.Kind() == reflect.Map: + return mapReflect{valueReflect: r}.Unstructured() + case r.IsList(): + return listReflect{r.Value}.Unstructured() + case r.IsString(): + return r.AsString() + case r.IsInt(): + return r.AsInt() + case r.IsBool(): + return r.AsBool() + case r.IsFloat(): + return r.AsFloat() + default: + panic(fmt.Sprintf("value of type %s is not a supported by value reflector", val.Type())) + } +} |