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Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/conversion/converter.go')
| -rw-r--r-- | vendor/k8s.io/apimachinery/pkg/conversion/converter.go | 898 |
1 files changed, 898 insertions, 0 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/conversion/converter.go b/vendor/k8s.io/apimachinery/pkg/conversion/converter.go new file mode 100644 index 000000000..7854c207c --- /dev/null +++ b/vendor/k8s.io/apimachinery/pkg/conversion/converter.go @@ -0,0 +1,898 @@ +/* +Copyright 2014 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 conversion + +import ( + "fmt" + "reflect" +) + +type typePair struct { + source reflect.Type + dest reflect.Type +} + +type typeNamePair struct { + fieldType reflect.Type + fieldName string +} + +// DebugLogger allows you to get debugging messages if necessary. +type DebugLogger interface { + Logf(format string, args ...interface{}) +} + +type NameFunc func(t reflect.Type) string + +var DefaultNameFunc = func(t reflect.Type) string { return t.Name() } + +type GenericConversionFunc func(a, b interface{}, scope Scope) (bool, error) + +// Converter knows how to convert one type to another. +type Converter struct { + // Map from the conversion pair to a function which can + // do the conversion. + conversionFuncs ConversionFuncs + generatedConversionFuncs ConversionFuncs + + // genericConversions are called during normal conversion to offer a "fast-path" + // that avoids all reflection. These methods are not called outside of the .Convert() + // method. + genericConversions []GenericConversionFunc + + // Set of conversions that should be treated as a no-op + ignoredConversions map[typePair]struct{} + + // This is a map from a source field type and name, to a list of destination + // field type and name. + structFieldDests map[typeNamePair][]typeNamePair + + // Allows for the opposite lookup of structFieldDests. So that SourceFromDest + // copy flag also works. So this is a map of destination field name, to potential + // source field name and type to look for. + structFieldSources map[typeNamePair][]typeNamePair + + // Map from an input type to a function which can apply a key name mapping + inputFieldMappingFuncs map[reflect.Type]FieldMappingFunc + + // Map from an input type to a set of default conversion flags. + inputDefaultFlags map[reflect.Type]FieldMatchingFlags + + // If non-nil, will be called to print helpful debugging info. Quite verbose. + Debug DebugLogger + + // nameFunc is called to retrieve the name of a type; this name is used for the + // purpose of deciding whether two types match or not (i.e., will we attempt to + // do a conversion). The default returns the go type name. + nameFunc func(t reflect.Type) string +} + +// NewConverter creates a new Converter object. +func NewConverter(nameFn NameFunc) *Converter { + c := &Converter{ + conversionFuncs: NewConversionFuncs(), + generatedConversionFuncs: NewConversionFuncs(), + ignoredConversions: make(map[typePair]struct{}), + nameFunc: nameFn, + structFieldDests: make(map[typeNamePair][]typeNamePair), + structFieldSources: make(map[typeNamePair][]typeNamePair), + + inputFieldMappingFuncs: make(map[reflect.Type]FieldMappingFunc), + inputDefaultFlags: make(map[reflect.Type]FieldMatchingFlags), + } + c.RegisterConversionFunc(Convert_Slice_byte_To_Slice_byte) + return c +} + +// AddGenericConversionFunc adds a function that accepts the ConversionFunc call pattern +// (for two conversion types) to the converter. These functions are checked first during +// a normal conversion, but are otherwise not called. Use AddConversionFuncs when registering +// typed conversions. +func (c *Converter) AddGenericConversionFunc(fn GenericConversionFunc) { + c.genericConversions = append(c.genericConversions, fn) +} + +// WithConversions returns a Converter that is a copy of c but with the additional +// fns merged on top. +func (c *Converter) WithConversions(fns ConversionFuncs) *Converter { + copied := *c + copied.conversionFuncs = c.conversionFuncs.Merge(fns) + return &copied +} + +// DefaultMeta returns the conversion FieldMappingFunc and meta for a given type. +func (c *Converter) DefaultMeta(t reflect.Type) (FieldMatchingFlags, *Meta) { + return c.inputDefaultFlags[t], &Meta{ + KeyNameMapping: c.inputFieldMappingFuncs[t], + } +} + +// Convert_Slice_byte_To_Slice_byte prevents recursing into every byte +func Convert_Slice_byte_To_Slice_byte(in *[]byte, out *[]byte, s Scope) error { + if *in == nil { + *out = nil + return nil + } + *out = make([]byte, len(*in)) + copy(*out, *in) + return nil +} + +// Scope is passed to conversion funcs to allow them to continue an ongoing conversion. +// If multiple converters exist in the system, Scope will allow you to use the correct one +// from a conversion function--that is, the one your conversion function was called by. +type Scope interface { + // Call Convert to convert sub-objects. Note that if you call it with your own exact + // parameters, you'll run out of stack space before anything useful happens. + Convert(src, dest interface{}, flags FieldMatchingFlags) error + + // DefaultConvert performs the default conversion, without calling a conversion func + // on the current stack frame. This makes it safe to call from a conversion func. + DefaultConvert(src, dest interface{}, flags FieldMatchingFlags) error + + // SrcTags and DestTags contain the struct tags that src and dest had, respectively. + // If the enclosing object was not a struct, then these will contain no tags, of course. + SrcTag() reflect.StructTag + DestTag() reflect.StructTag + + // Flags returns the flags with which the conversion was started. + Flags() FieldMatchingFlags + + // Meta returns any information originally passed to Convert. + Meta() *Meta +} + +// FieldMappingFunc can convert an input field value into different values, depending on +// the value of the source or destination struct tags. +type FieldMappingFunc func(key string, sourceTag, destTag reflect.StructTag) (source string, dest string) + +func NewConversionFuncs() ConversionFuncs { + return ConversionFuncs{fns: make(map[typePair]reflect.Value)} +} + +type ConversionFuncs struct { + fns map[typePair]reflect.Value +} + +// Add adds the provided conversion functions to the lookup table - they must have the signature +// `func(type1, type2, Scope) error`. Functions are added in the order passed and will override +// previously registered pairs. +func (c ConversionFuncs) Add(fns ...interface{}) error { + for _, fn := range fns { + fv := reflect.ValueOf(fn) + ft := fv.Type() + if err := verifyConversionFunctionSignature(ft); err != nil { + return err + } + c.fns[typePair{ft.In(0).Elem(), ft.In(1).Elem()}] = fv + } + return nil +} + +// Merge returns a new ConversionFuncs that contains all conversions from +// both other and c, with other conversions taking precedence. +func (c ConversionFuncs) Merge(other ConversionFuncs) ConversionFuncs { + merged := NewConversionFuncs() + for k, v := range c.fns { + merged.fns[k] = v + } + for k, v := range other.fns { + merged.fns[k] = v + } + return merged +} + +// Meta is supplied by Scheme, when it calls Convert. +type Meta struct { + // KeyNameMapping is an optional function which may map the listed key (field name) + // into a source and destination value. + KeyNameMapping FieldMappingFunc + // Context is an optional field that callers may use to pass info to conversion functions. + Context interface{} +} + +// scope contains information about an ongoing conversion. +type scope struct { + converter *Converter + meta *Meta + flags FieldMatchingFlags + + // srcStack & destStack are separate because they may not have a 1:1 + // relationship. + srcStack scopeStack + destStack scopeStack +} + +type scopeStackElem struct { + tag reflect.StructTag + value reflect.Value + key string +} + +type scopeStack []scopeStackElem + +func (s *scopeStack) pop() { + n := len(*s) + *s = (*s)[:n-1] +} + +func (s *scopeStack) push(e scopeStackElem) { + *s = append(*s, e) +} + +func (s *scopeStack) top() *scopeStackElem { + return &(*s)[len(*s)-1] +} + +func (s scopeStack) describe() string { + desc := "" + if len(s) > 1 { + desc = "(" + s[1].value.Type().String() + ")" + } + for i, v := range s { + if i < 2 { + // First layer on stack is not real; second is handled specially above. + continue + } + if v.key == "" { + desc += fmt.Sprintf(".%v", v.value.Type()) + } else { + desc += fmt.Sprintf(".%v", v.key) + } + } + return desc +} + +// Formats src & dest as indices for printing. +func (s *scope) setIndices(src, dest int) { + s.srcStack.top().key = fmt.Sprintf("[%v]", src) + s.destStack.top().key = fmt.Sprintf("[%v]", dest) +} + +// Formats src & dest as map keys for printing. +func (s *scope) setKeys(src, dest interface{}) { + s.srcStack.top().key = fmt.Sprintf(`["%v"]`, src) + s.destStack.top().key = fmt.Sprintf(`["%v"]`, dest) +} + +// Convert continues a conversion. +func (s *scope) Convert(src, dest interface{}, flags FieldMatchingFlags) error { + return s.converter.Convert(src, dest, flags, s.meta) +} + +// DefaultConvert continues a conversion, performing a default conversion (no conversion func) +// for the current stack frame. +func (s *scope) DefaultConvert(src, dest interface{}, flags FieldMatchingFlags) error { + return s.converter.DefaultConvert(src, dest, flags, s.meta) +} + +// SrcTag returns the tag of the struct containing the current source item, if any. +func (s *scope) SrcTag() reflect.StructTag { + return s.srcStack.top().tag +} + +// DestTag returns the tag of the struct containing the current dest item, if any. +func (s *scope) DestTag() reflect.StructTag { + return s.destStack.top().tag +} + +// Flags returns the flags with which the current conversion was started. +func (s *scope) Flags() FieldMatchingFlags { + return s.flags +} + +// Meta returns the meta object that was originally passed to Convert. +func (s *scope) Meta() *Meta { + return s.meta +} + +// describe prints the path to get to the current (source, dest) values. +func (s *scope) describe() (src, dest string) { + return s.srcStack.describe(), s.destStack.describe() +} + +// error makes an error that includes information about where we were in the objects +// we were asked to convert. +func (s *scope) errorf(message string, args ...interface{}) error { + srcPath, destPath := s.describe() + where := fmt.Sprintf("converting %v to %v: ", srcPath, destPath) + return fmt.Errorf(where+message, args...) +} + +// Verifies whether a conversion function has a correct signature. +func verifyConversionFunctionSignature(ft reflect.Type) error { + if ft.Kind() != reflect.Func { + return fmt.Errorf("expected func, got: %v", ft) + } + if ft.NumIn() != 3 { + return fmt.Errorf("expected three 'in' params, got: %v", ft) + } + if ft.NumOut() != 1 { + return fmt.Errorf("expected one 'out' param, got: %v", ft) + } + if ft.In(0).Kind() != reflect.Ptr { + return fmt.Errorf("expected pointer arg for 'in' param 0, got: %v", ft) + } + if ft.In(1).Kind() != reflect.Ptr { + return fmt.Errorf("expected pointer arg for 'in' param 1, got: %v", ft) + } + scopeType := Scope(nil) + if e, a := reflect.TypeOf(&scopeType).Elem(), ft.In(2); e != a { + return fmt.Errorf("expected '%v' arg for 'in' param 2, got '%v' (%v)", e, a, ft) + } + var forErrorType error + // This convolution is necessary, otherwise TypeOf picks up on the fact + // that forErrorType is nil. + errorType := reflect.TypeOf(&forErrorType).Elem() + if ft.Out(0) != errorType { + return fmt.Errorf("expected error return, got: %v", ft) + } + return nil +} + +// RegisterConversionFunc registers a conversion func with the +// Converter. conversionFunc must take three parameters: a pointer to the input +// type, a pointer to the output type, and a conversion.Scope (which should be +// used if recursive conversion calls are desired). It must return an error. +// +// Example: +// c.RegisterConversionFunc( +// func(in *Pod, out *v1.Pod, s Scope) error { +// // conversion logic... +// return nil +// }) +func (c *Converter) RegisterConversionFunc(conversionFunc interface{}) error { + return c.conversionFuncs.Add(conversionFunc) +} + +// Similar to RegisterConversionFunc, but registers conversion function that were +// automatically generated. +func (c *Converter) RegisterGeneratedConversionFunc(conversionFunc interface{}) error { + return c.generatedConversionFuncs.Add(conversionFunc) +} + +// RegisterIgnoredConversion registers a "no-op" for conversion, where any requested +// conversion between from and to is ignored. +func (c *Converter) RegisterIgnoredConversion(from, to interface{}) error { + typeFrom := reflect.TypeOf(from) + typeTo := reflect.TypeOf(to) + if reflect.TypeOf(from).Kind() != reflect.Ptr { + return fmt.Errorf("expected pointer arg for 'from' param 0, got: %v", typeFrom) + } + if typeTo.Kind() != reflect.Ptr { + return fmt.Errorf("expected pointer arg for 'to' param 1, got: %v", typeTo) + } + c.ignoredConversions[typePair{typeFrom.Elem(), typeTo.Elem()}] = struct{}{} + return nil +} + +// IsConversionIgnored returns true if the specified objects should be dropped during +// conversion. +func (c *Converter) IsConversionIgnored(inType, outType reflect.Type) bool { + _, found := c.ignoredConversions[typePair{inType, outType}] + return found +} + +func (c *Converter) HasConversionFunc(inType, outType reflect.Type) bool { + _, found := c.conversionFuncs.fns[typePair{inType, outType}] + return found +} + +func (c *Converter) ConversionFuncValue(inType, outType reflect.Type) (reflect.Value, bool) { + value, found := c.conversionFuncs.fns[typePair{inType, outType}] + return value, found +} + +// SetStructFieldCopy registers a correspondence. Whenever a struct field is encountered +// which has a type and name matching srcFieldType and srcFieldName, it wil be copied +// into the field in the destination struct matching destFieldType & Name, if such a +// field exists. +// May be called multiple times, even for the same source field & type--all applicable +// copies will be performed. +func (c *Converter) SetStructFieldCopy(srcFieldType interface{}, srcFieldName string, destFieldType interface{}, destFieldName string) error { + st := reflect.TypeOf(srcFieldType) + dt := reflect.TypeOf(destFieldType) + srcKey := typeNamePair{st, srcFieldName} + destKey := typeNamePair{dt, destFieldName} + c.structFieldDests[srcKey] = append(c.structFieldDests[srcKey], destKey) + c.structFieldSources[destKey] = append(c.structFieldSources[destKey], srcKey) + return nil +} + +// RegisterInputDefaults registers a field name mapping function, used when converting +// from maps to structs. Inputs to the conversion methods are checked for this type and a mapping +// applied automatically if the input matches in. A set of default flags for the input conversion +// may also be provided, which will be used when no explicit flags are requested. +func (c *Converter) RegisterInputDefaults(in interface{}, fn FieldMappingFunc, defaultFlags FieldMatchingFlags) error { + fv := reflect.ValueOf(in) + ft := fv.Type() + if ft.Kind() != reflect.Ptr { + return fmt.Errorf("expected pointer 'in' argument, got: %v", ft) + } + c.inputFieldMappingFuncs[ft] = fn + c.inputDefaultFlags[ft] = defaultFlags + return nil +} + +// FieldMatchingFlags contains a list of ways in which struct fields could be +// copied. These constants may be | combined. +type FieldMatchingFlags int + +const ( + // Loop through destination fields, search for matching source + // field to copy it from. Source fields with no corresponding + // destination field will be ignored. If SourceToDest is + // specified, this flag is ignored. If neither is specified, + // or no flags are passed, this flag is the default. + DestFromSource FieldMatchingFlags = 0 + // Loop through source fields, search for matching dest field + // to copy it into. Destination fields with no corresponding + // source field will be ignored. + SourceToDest FieldMatchingFlags = 1 << iota + // Don't treat it as an error if the corresponding source or + // dest field can't be found. + IgnoreMissingFields + // Don't require type names to match. + AllowDifferentFieldTypeNames +) + +// IsSet returns true if the given flag or combination of flags is set. +func (f FieldMatchingFlags) IsSet(flag FieldMatchingFlags) bool { + if flag == DestFromSource { + // The bit logic doesn't work on the default value. + return f&SourceToDest != SourceToDest + } + return f&flag == flag +} + +// Convert will translate src to dest if it knows how. Both must be pointers. +// If no conversion func is registered and the default copying mechanism +// doesn't work on this type pair, an error will be returned. +// Read the comments on the various FieldMatchingFlags constants to understand +// what the 'flags' parameter does. +// 'meta' is given to allow you to pass information to conversion functions, +// it is not used by Convert() other than storing it in the scope. +// Not safe for objects with cyclic references! +func (c *Converter) Convert(src, dest interface{}, flags FieldMatchingFlags, meta *Meta) error { + if len(c.genericConversions) > 0 { + // TODO: avoid scope allocation + s := &scope{converter: c, flags: flags, meta: meta} + for _, fn := range c.genericConversions { + if ok, err := fn(src, dest, s); ok { + return err + } + } + } + return c.doConversion(src, dest, flags, meta, c.convert) +} + +// DefaultConvert will translate src to dest if it knows how. Both must be pointers. +// No conversion func is used. If the default copying mechanism +// doesn't work on this type pair, an error will be returned. +// Read the comments on the various FieldMatchingFlags constants to understand +// what the 'flags' parameter does. +// 'meta' is given to allow you to pass information to conversion functions, +// it is not used by DefaultConvert() other than storing it in the scope. +// Not safe for objects with cyclic references! +func (c *Converter) DefaultConvert(src, dest interface{}, flags FieldMatchingFlags, meta *Meta) error { + return c.doConversion(src, dest, flags, meta, c.defaultConvert) +} + +type conversionFunc func(sv, dv reflect.Value, scope *scope) error + +func (c *Converter) doConversion(src, dest interface{}, flags FieldMatchingFlags, meta *Meta, f conversionFunc) error { + dv, err := EnforcePtr(dest) + if err != nil { + return err + } + if !dv.CanAddr() && !dv.CanSet() { + return fmt.Errorf("can't write to dest") + } + sv, err := EnforcePtr(src) + if err != nil { + return err + } + s := &scope{ + converter: c, + flags: flags, + meta: meta, + } + // Leave something on the stack, so that calls to struct tag getters never fail. + s.srcStack.push(scopeStackElem{}) + s.destStack.push(scopeStackElem{}) + return f(sv, dv, s) +} + +// callCustom calls 'custom' with sv & dv. custom must be a conversion function. +func (c *Converter) callCustom(sv, dv, custom reflect.Value, scope *scope) error { + if !sv.CanAddr() { + sv2 := reflect.New(sv.Type()) + sv2.Elem().Set(sv) + sv = sv2 + } else { + sv = sv.Addr() + } + if !dv.CanAddr() { + if !dv.CanSet() { + return scope.errorf("can't addr or set dest.") + } + dvOrig := dv + dv := reflect.New(dvOrig.Type()) + defer func() { dvOrig.Set(dv) }() + } else { + dv = dv.Addr() + } + args := []reflect.Value{sv, dv, reflect.ValueOf(scope)} + ret := custom.Call(args)[0].Interface() + // This convolution is necessary because nil interfaces won't convert + // to errors. + if ret == nil { + return nil + } + return ret.(error) +} + +// convert recursively copies sv into dv, calling an appropriate conversion function if +// one is registered. +func (c *Converter) convert(sv, dv reflect.Value, scope *scope) error { + dt, st := dv.Type(), sv.Type() + pair := typePair{st, dt} + + // ignore conversions of this type + if _, ok := c.ignoredConversions[pair]; ok { + if c.Debug != nil { + c.Debug.Logf("Ignoring conversion of '%v' to '%v'", st, dt) + } + return nil + } + + // Convert sv to dv. + if fv, ok := c.conversionFuncs.fns[pair]; ok { + if c.Debug != nil { + c.Debug.Logf("Calling custom conversion of '%v' to '%v'", st, dt) + } + return c.callCustom(sv, dv, fv, scope) + } + if fv, ok := c.generatedConversionFuncs.fns[pair]; ok { + if c.Debug != nil { + c.Debug.Logf("Calling generated conversion of '%v' to '%v'", st, dt) + } + return c.callCustom(sv, dv, fv, scope) + } + + return c.defaultConvert(sv, dv, scope) +} + +// defaultConvert recursively copies sv into dv. no conversion function is called +// for the current stack frame (but conversion functions may be called for nested objects) +func (c *Converter) defaultConvert(sv, dv reflect.Value, scope *scope) error { + dt, st := dv.Type(), sv.Type() + + if !dv.CanSet() { + return scope.errorf("Cannot set dest. (Tried to deep copy something with unexported fields?)") + } + + if !scope.flags.IsSet(AllowDifferentFieldTypeNames) && c.nameFunc(dt) != c.nameFunc(st) { + return scope.errorf( + "type names don't match (%v, %v), and no conversion 'func (%v, %v) error' registered.", + c.nameFunc(st), c.nameFunc(dt), st, dt) + } + + switch st.Kind() { + case reflect.Map, reflect.Ptr, reflect.Slice, reflect.Interface, reflect.Struct: + // Don't copy these via assignment/conversion! + default: + // This should handle all simple types. + if st.AssignableTo(dt) { + dv.Set(sv) + return nil + } + if st.ConvertibleTo(dt) { + dv.Set(sv.Convert(dt)) + return nil + } + } + + if c.Debug != nil { + c.Debug.Logf("Trying to convert '%v' to '%v'", st, dt) + } + + scope.srcStack.push(scopeStackElem{value: sv}) + scope.destStack.push(scopeStackElem{value: dv}) + defer scope.srcStack.pop() + defer scope.destStack.pop() + + switch dv.Kind() { + case reflect.Struct: + return c.convertKV(toKVValue(sv), toKVValue(dv), scope) + case reflect.Slice: + if sv.IsNil() { + // Don't make a zero-length slice. + dv.Set(reflect.Zero(dt)) + return nil + } + dv.Set(reflect.MakeSlice(dt, sv.Len(), sv.Cap())) + for i := 0; i < sv.Len(); i++ { + scope.setIndices(i, i) + if err := c.convert(sv.Index(i), dv.Index(i), scope); err != nil { + return err + } + } + case reflect.Ptr: + if sv.IsNil() { + // Don't copy a nil ptr! + dv.Set(reflect.Zero(dt)) + return nil + } + dv.Set(reflect.New(dt.Elem())) + switch st.Kind() { + case reflect.Ptr, reflect.Interface: + return c.convert(sv.Elem(), dv.Elem(), scope) + default: + return c.convert(sv, dv.Elem(), scope) + } + case reflect.Map: + if sv.IsNil() { + // Don't copy a nil ptr! + dv.Set(reflect.Zero(dt)) + return nil + } + dv.Set(reflect.MakeMap(dt)) + for _, sk := range sv.MapKeys() { + dk := reflect.New(dt.Key()).Elem() + if err := c.convert(sk, dk, scope); err != nil { + return err + } + dkv := reflect.New(dt.Elem()).Elem() + scope.setKeys(sk.Interface(), dk.Interface()) + // TODO: sv.MapIndex(sk) may return a value with CanAddr() == false, + // because a map[string]struct{} does not allow a pointer reference. + // Calling a custom conversion function defined for the map value + // will panic. Example is PodInfo map[string]ContainerStatus. + if err := c.convert(sv.MapIndex(sk), dkv, scope); err != nil { + return err + } + dv.SetMapIndex(dk, dkv) + } + case reflect.Interface: + if sv.IsNil() { + // Don't copy a nil interface! + dv.Set(reflect.Zero(dt)) + return nil + } + tmpdv := reflect.New(sv.Elem().Type()).Elem() + if err := c.convert(sv.Elem(), tmpdv, scope); err != nil { + return err + } + dv.Set(reflect.ValueOf(tmpdv.Interface())) + return nil + default: + return scope.errorf("couldn't copy '%v' into '%v'; didn't understand types", st, dt) + } + return nil +} + +var stringType = reflect.TypeOf("") + +func toKVValue(v reflect.Value) kvValue { + switch v.Kind() { + case reflect.Struct: + return structAdaptor(v) + case reflect.Map: + if v.Type().Key().AssignableTo(stringType) { + return stringMapAdaptor(v) + } + } + + return nil +} + +// kvValue lets us write the same conversion logic to work with both maps +// and structs. Only maps with string keys make sense for this. +type kvValue interface { + // returns all keys, as a []string. + keys() []string + // Will just return "" for maps. + tagOf(key string) reflect.StructTag + // Will return the zero Value if the key doesn't exist. + value(key string) reflect.Value + // Maps require explicit setting-- will do nothing for structs. + // Returns false on failure. + confirmSet(key string, v reflect.Value) bool +} + +type stringMapAdaptor reflect.Value + +func (a stringMapAdaptor) len() int { + return reflect.Value(a).Len() +} + +func (a stringMapAdaptor) keys() []string { + v := reflect.Value(a) + keys := make([]string, v.Len()) + for i, v := range v.MapKeys() { + if v.IsNil() { + continue + } + switch t := v.Interface().(type) { + case string: + keys[i] = t + } + } + return keys +} + +func (a stringMapAdaptor) tagOf(key string) reflect.StructTag { + return "" +} + +func (a stringMapAdaptor) value(key string) reflect.Value { + return reflect.Value(a).MapIndex(reflect.ValueOf(key)) +} + +func (a stringMapAdaptor) confirmSet(key string, v reflect.Value) bool { + return true +} + +type structAdaptor reflect.Value + +func (a structAdaptor) len() int { + v := reflect.Value(a) + return v.Type().NumField() +} + +func (a structAdaptor) keys() []string { + v := reflect.Value(a) + t := v.Type() + keys := make([]string, t.NumField()) + for i := range keys { + keys[i] = t.Field(i).Name + } + return keys +} + +func (a structAdaptor) tagOf(key string) reflect.StructTag { + v := reflect.Value(a) + field, ok := v.Type().FieldByName(key) + if ok { + return field.Tag + } + return "" +} + +func (a structAdaptor) value(key string) reflect.Value { + v := reflect.Value(a) + return v.FieldByName(key) +} + +func (a structAdaptor) confirmSet(key string, v reflect.Value) bool { + return true +} + +// convertKV can convert things that consist of key/value pairs, like structs +// and some maps. +func (c *Converter) convertKV(skv, dkv kvValue, scope *scope) error { + if skv == nil || dkv == nil { + // TODO: add keys to stack to support really understandable error messages. + return fmt.Errorf("Unable to convert %#v to %#v", skv, dkv) + } + + lister := dkv + if scope.flags.IsSet(SourceToDest) { + lister = skv + } + + var mapping FieldMappingFunc + if scope.meta != nil && scope.meta.KeyNameMapping != nil { + mapping = scope.meta.KeyNameMapping + } + + for _, key := range lister.keys() { + if found, err := c.checkField(key, skv, dkv, scope); found { + if err != nil { + return err + } + continue + } + stag := skv.tagOf(key) + dtag := dkv.tagOf(key) + skey := key + dkey := key + if mapping != nil { + skey, dkey = scope.meta.KeyNameMapping(key, stag, dtag) + } + + df := dkv.value(dkey) + sf := skv.value(skey) + if !df.IsValid() || !sf.IsValid() { + switch { + case scope.flags.IsSet(IgnoreMissingFields): + // No error. + case scope.flags.IsSet(SourceToDest): + return scope.errorf("%v not present in dest", dkey) + default: + return scope.errorf("%v not present in src", skey) + } + continue + } + scope.srcStack.top().key = skey + scope.srcStack.top().tag = stag + scope.destStack.top().key = dkey + scope.destStack.top().tag = dtag + if err := c.convert(sf, df, scope); err != nil { + return err + } + } + return nil +} + +// checkField returns true if the field name matches any of the struct +// field copying rules. The error should be ignored if it returns false. +func (c *Converter) checkField(fieldName string, skv, dkv kvValue, scope *scope) (bool, error) { + replacementMade := false + if scope.flags.IsSet(DestFromSource) { + df := dkv.value(fieldName) + if !df.IsValid() { + return false, nil + } + destKey := typeNamePair{df.Type(), fieldName} + // Check each of the potential source (type, name) pairs to see if they're + // present in sv. + for _, potentialSourceKey := range c.structFieldSources[destKey] { + sf := skv.value(potentialSourceKey.fieldName) + if !sf.IsValid() { + continue + } + if sf.Type() == potentialSourceKey.fieldType { + // Both the source's name and type matched, so copy. + scope.srcStack.top().key = potentialSourceKey.fieldName + scope.destStack.top().key = fieldName + if err := c.convert(sf, df, scope); err != nil { + return true, err + } + dkv.confirmSet(fieldName, df) + replacementMade = true + } + } + return replacementMade, nil + } + + sf := skv.value(fieldName) + if !sf.IsValid() { + return false, nil + } + srcKey := typeNamePair{sf.Type(), fieldName} + // Check each of the potential dest (type, name) pairs to see if they're + // present in dv. + for _, potentialDestKey := range c.structFieldDests[srcKey] { + df := dkv.value(potentialDestKey.fieldName) + if !df.IsValid() { + continue + } + if df.Type() == potentialDestKey.fieldType { + // Both the dest's name and type matched, so copy. + scope.srcStack.top().key = fieldName + scope.destStack.top().key = potentialDestKey.fieldName + if err := c.convert(sf, df, scope); err != nil { + return true, err + } + dkv.confirmSet(potentialDestKey.fieldName, df) + replacementMade = true + } + } + return replacementMade, nil +} |