Separate projection cloning and value comparison

projection.go

@@ -1,6 +1,7 @@
 package configkit
 
 import (
+	"cmp"
 	"encoding"
 	"math"
 	"reflect"
@@ -12,35 +13,6 @@ import (
 	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
 )
 
-type projectionLimits struct {
-	depth int
-	nodes int
-}
-
-func defaultProjectionLimits() projectionLimits {
-	return projectionLimits{depth: maxDocumentDepth, nodes: maxDocumentNodes}
-}
-
-type projectionIssue struct {
-	code    Code
-	path    Path
-	message string
-}
-
-type valueVisit struct {
-	typeOf reflect.Type
-	kind   reflect.Kind
-	ptr    uintptr
-}
-
-type valueOperation struct {
-	preserveSecrets bool
-	schema          *schemaDescriptor
-	limits          projectionLimits
-	active          map[valueVisit]bool
-	nodes           int
-}
-
 func projectConfiguration(schema *schemaDescriptor, value reflect.Value, limits projectionLimits) (*document.Node, *projectionIssue) {
 	if schema == nil || schema.root == nil || !value.IsValid() || value.Type() != schema.root.typeOf {
 		return nil, &projectionIssue{code: CodeSchemaUnsupportedType, message: "configuration value does not match its schema"}
@@ -49,19 +21,6 @@ func projectConfiguration(schema *schemaDescriptor, value reflect.Value, limits
 	return operation.project(value, schema.root, Path{}, 0)
 }
 
-func cloneConfiguration(schema *schemaDescriptor, value reflect.Value, limits projectionLimits) (reflect.Value, *projectionIssue) {
-	return cloneConfigurationState(schema, value, limits, false)
-}
-
-// Publication copies preserve only already-validated private reference state.
-func cloneConfigurationState(schema *schemaDescriptor, value reflect.Value, limits projectionLimits, preserveSecrets bool) (reflect.Value, *projectionIssue) {
-	if schema == nil || schema.root == nil || !value.IsValid() || value.Type() != schema.root.typeOf {
-		return reflect.Value{}, &projectionIssue{code: CodeSchemaUnsupportedType, message: "configuration value does not match its schema"}
-	}
-	operation := valueOperation{schema: schema, limits: limits, active: make(map[valueVisit]bool), preserveSecrets: preserveSecrets}
-	return operation.clone(value, schema.root, Path{}, 0)
-}
-
 func (o *valueOperation) project(value reflect.Value, descriptor *typeDescriptor, path Path, depth int) (*document.Node, *projectionIssue) {
 	if issue := o.checkDepth(path, depth); issue != nil {
 		return nil, issue
@@ -149,7 +108,7 @@ func (o *valueOperation) project(value reflect.Value, descriptor *typeDescriptor
 		result.Mapping = make([]document.Entry, 0, value.Len())
 		keys := value.MapKeys()
 		slices.SortFunc(keys, func(left, right reflect.Value) int {
-			return cmpString(left.String(), right.String())
+			return cmp.Compare(left.String(), right.String())
 		})
 		for _, key := range keys {
 			childPath := path.Key(key.String())
@@ -258,171 +217,6 @@ func (o *valueOperation) project(value reflect.Value, descriptor *typeDescriptor
 	}
 }
 
-func (o *valueOperation) clone(value reflect.Value, descriptor *typeDescriptor, path Path, depth int) (reflect.Value, *projectionIssue) {
-	if issue := o.checkDepth(path, depth); issue != nil {
-		return reflect.Value{}, issue
-	}
-	if descriptor.kind == descriptorPointer {
-		if value.IsNil() {
-			return reflect.Zero(value.Type()), nil
-		}
-		leave, issue := o.enter(value, path)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		defer leave()
-		child, issue := o.clone(value.Elem(), descriptor.element, path, depth)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		result := reflect.New(value.Type().Elem())
-		result.Elem().Set(child)
-		return result, nil
-	}
-
-	switch descriptor.kind {
-	case descriptorStruct:
-		result := reflect.New(value.Type()).Elem()
-		for _, member := range descriptor.members {
-			memberPath, memberDepth := path, depth
-			if !member.inline {
-				memberPath, memberDepth = path.Key(member.name), depth+1
-			}
-			cloned, issue := o.clone(value.Field(member.index), member.descriptor, memberPath, memberDepth)
-			if issue != nil {
-				return reflect.Value{}, issue
-			}
-			result.Field(member.index).Set(cloned)
-		}
-		return result, nil
-	case descriptorMap:
-		if value.IsNil() {
-			return reflect.Zero(value.Type()), nil
-		}
-		leave, issue := o.enter(value, path)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		defer leave()
-		result := reflect.MakeMapWithSize(value.Type(), value.Len())
-		for _, key := range value.MapKeys() {
-			cloned, issue := o.clone(value.MapIndex(key), descriptor.element, path.Key(key.String()), depth+1)
-			if issue != nil {
-				return reflect.Value{}, issue
-			}
-			result.SetMapIndex(key, cloned)
-		}
-		return result, nil
-	case descriptorSlice:
-		if value.IsNil() {
-			return reflect.Zero(value.Type()), nil
-		}
-		leave, issue := o.enter(value, path)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		defer leave()
-		result := reflect.MakeSlice(value.Type(), value.Len(), value.Len())
-		for i := 0; i < value.Len(); i++ {
-			cloned, issue := o.clone(value.Index(i), descriptor.element, path.Index(i), depth+1)
-			if issue != nil {
-				return reflect.Value{}, issue
-			}
-			result.Index(i).Set(cloned)
-		}
-		return result, nil
-	case descriptorArray:
-		result := reflect.New(value.Type()).Elem()
-		for i := 0; i < value.Len(); i++ {
-			cloned, issue := o.clone(value.Index(i), descriptor.element, path.Index(i), depth+1)
-			if issue != nil {
-				return reflect.Value{}, issue
-			}
-			result.Index(i).Set(cloned)
-		}
-		return result, nil
-	case descriptorDynamic:
-		if value.IsNil() {
-			return reflect.Zero(value.Type()), nil
-		}
-		concrete := value.Elem()
-		dynamic, issue := o.dynamicDescriptor(concrete.Type(), path)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		cloned, issue := o.clone(concrete, dynamic, path, depth)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		result := reflect.New(value.Type()).Elem()
-		result.Set(cloned)
-		return result, nil
-	case descriptorSecret:
-		result := reflect.New(value.Type()).Elem()
-		reference := value.Interface().(Secret)
-		if o.preserveSecrets {
-			result.Set(value)
-		} else if reference.specified {
-			result.Set(reflect.ValueOf(SecretEnv(reference.EnvName())))
-		}
-		return result, nil
-	case descriptorText:
-		text, issue := marshalCanonicalText(value, path)
-		if issue != nil {
-			return reflect.Value{}, issue
-		}
-		result := reflect.New(value.Type()).Elem()
-		unmarshaler := result.Addr().Interface().(encoding.TextUnmarshaler)
-		if err := unmarshaler.UnmarshalText([]byte(text)); err != nil {
-			return reflect.Value{}, &projectionIssue{code: CodeSchemaCodec, path: path.clone(), message: "custom text scalar could not be reconstructed"}
-		}
-		return result, nil
-	case descriptorFloat:
-		if math.IsNaN(value.Float()) || math.IsInf(value.Float(), 0) {
-			return reflect.Value{}, &projectionIssue{code: CodeSchemaNonFinite, path: path.clone(), message: "configuration float must be finite"}
-		}
-		fallthrough
-	default:
-		result := reflect.New(value.Type()).Elem()
-		result.Set(value)
-		return result, nil
-	}
-}
-
-func (o *valueOperation) dynamicDescriptor(current reflect.Type, path Path) (*typeDescriptor, *projectionIssue) {
-	if current == secretType {
-		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration values cannot establish secret-reference semantics"}
-	}
-	builder := schemaBuilder{cache: o.schema.types, building: make(map[reflect.Type]bool)}
-	descriptor, issue := builder.describe(current, path)
-	if issue != nil {
-		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration value has an unsupported type"}
-	}
-	if descriptorContainsSecret(descriptor, make(map[*typeDescriptor]bool)) {
-		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration values cannot establish secret-reference semantics"}
-	}
-	return descriptor, nil
-}
-
-func descriptorContainsSecret(descriptor *typeDescriptor, visited map[*typeDescriptor]bool) bool {
-	if descriptor == nil || visited[descriptor] {
-		return false
-	}
-	if descriptor.kind == descriptorSecret {
-		return true
-	}
-	visited[descriptor] = true
-	if descriptorContainsSecret(descriptor.element, visited) {
-		return true
-	}
-	for _, member := range descriptor.members {
-		if descriptorContainsSecret(member.descriptor, visited) {
-			return true
-		}
-	}
-	return false
-}
-
 func (o *valueOperation) node(kind document.Kind, path Path, depth int) (*document.Node, *projectionIssue) {
 	if issue := o.checkDepth(path, depth); issue != nil {
 		return nil, issue
@@ -433,64 +227,6 @@ func (o *valueOperation) node(kind document.Kind, path Path, depth int) (*docume
 	return &document.Node{Kind: kind}, nil
 }
 
-func (o *valueOperation) charge(path Path) *projectionIssue {
-	o.nodes++
-	if o.limits.nodes >= 0 && o.nodes > o.limits.nodes {
-		return &projectionIssue{code: CodeSchemaProjectionLimit, path: path.clone(), message: "configuration projection exceeds the node limit"}
-	}
-	return nil
-}
-
-func (o *valueOperation) checkDepth(path Path, depth int) *projectionIssue {
-	if depth > o.limits.depth {
-		return &projectionIssue{code: CodeSchemaProjectionLimit, path: path.clone(), message: "configuration projection exceeds the depth limit"}
-	}
-	return nil
-}
-
-func (o *valueOperation) enter(value reflect.Value, path Path) (func(), *projectionIssue) {
-	visit, ok := visitFor(value)
-	if !ok {
-		return func() {}, nil
-	}
-	if o.active[visit] {
-		return nil, &projectionIssue{code: CodeSchemaCycle, path: path.clone(), message: "configuration values must not contain cycles"}
-	}
-	o.active[visit] = true
-	return func() { delete(o.active, visit) }, nil
-}
-
-func visitFor(value reflect.Value) (valueVisit, bool) {
-	if isNilValue(value) {
-		return valueVisit{}, false
-	}
-	visit := valueVisit{typeOf: value.Type(), kind: value.Kind()}
-	switch value.Kind() {
-	case reflect.Pointer, reflect.Slice:
-		if value.Kind() == reflect.Slice && value.Len() == 0 {
-			return valueVisit{}, false
-		}
-		visit.ptr = value.Pointer()
-	case reflect.Map:
-		if value.Len() == 0 {
-			return valueVisit{}, false
-		}
-		visit.ptr = uintptr(value.UnsafePointer())
-	default:
-		return valueVisit{}, false
-	}
-	return visit, visit.ptr != 0
-}
-
-func isNilValue(value reflect.Value) bool {
-	switch value.Kind() {
-	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Pointer, reflect.Slice:
-		return value.IsNil()
-	default:
-		return false
-	}
-}
-
 func marshalCanonicalText(value reflect.Value, path Path) (string, *projectionIssue) {
 	var marshaler encoding.TextMarshaler
 	if value.CanInterface() {
@@ -510,113 +246,3 @@ func marshalCanonicalText(value reflect.Value, path Path) (string, *projectionIs
 	}
 	return string(text), nil
 }
-
-func cmpString(left, right string) int {
-	switch {
-	case left < right:
-		return -1
-	case left > right:
-		return 1
-	default:
-		return 0
-	}
-}
-
-type documentDeltaKind uint8
-
-const (
-	documentAdded documentDeltaKind = iota + 1
-	documentRemoved
-	documentReplaced
-)
-
-type documentDelta struct {
-	path Path
-	kind documentDeltaKind
-}
-
-func compareDocumentTrees(before, after *document.Node) []documentDelta {
-	var deltas []documentDelta
-	compareDocumentNode(before, after, Path{}, &deltas)
-	slices.SortFunc(deltas, func(left, right documentDelta) int {
-		if order := cmpString(left.path.String(), right.path.String()); order != 0 {
-			return order
-		}
-		return int(left.kind) - int(right.kind)
-	})
-	return deltas
-}
-
-func compareDocumentNode(before, after *document.Node, path Path, deltas *[]documentDelta) {
-	if before == nil && after == nil {
-		return
-	}
-	if before == nil {
-		*deltas = append(*deltas, documentDelta{path: path.clone(), kind: documentAdded})
-		return
-	}
-	if after == nil {
-		*deltas = append(*deltas, documentDelta{path: path.clone(), kind: documentRemoved})
-		return
-	}
-	if before.Kind != after.Kind {
-		*deltas = append(*deltas, documentDelta{path: path.clone(), kind: documentReplaced})
-		return
-	}
-	switch before.Kind {
-	case document.Mapping:
-		beforeEntries := make(map[string]*document.Node, len(before.Mapping))
-		afterEntries := make(map[string]*document.Node, len(after.Mapping))
-		keys := make(map[string]bool, len(before.Mapping)+len(after.Mapping))
-		for _, entry := range before.Mapping {
-			beforeEntries[entry.Key] = entry.Value
-			keys[entry.Key] = true
-		}
-		for _, entry := range after.Mapping {
-			afterEntries[entry.Key] = entry.Value
-			keys[entry.Key] = true
-		}
-		ordered := make([]string, 0, len(keys))
-		for key := range keys {
-			ordered = append(ordered, key)
-		}
-		slices.Sort(ordered)
-		for _, key := range ordered {
-			compareDocumentNode(beforeEntries[key], afterEntries[key], path.Key(key), deltas)
-		}
-	case document.Sequence:
-		if !documentNodesEqual(before, after) {
-			*deltas = append(*deltas, documentDelta{path: path.clone(), kind: documentReplaced})
-		}
-	default:
-		if before.Text != after.Text {
-			*deltas = append(*deltas, documentDelta{path: path.clone(), kind: documentReplaced})
-		}
-	}
-}
-
-func documentNodesEqual(left, right *document.Node) bool {
-	if left == nil || right == nil {
-		return left == right
-	}
-	if left.Kind != right.Kind || left.Text != right.Text || len(left.Mapping) != len(right.Mapping) || len(left.Sequence) != len(right.Sequence) {
-		return false
-	}
-	if left.Kind == document.Mapping {
-		leftMap := make(map[string]*document.Node, len(left.Mapping))
-		for _, entry := range left.Mapping {
-			leftMap[entry.Key] = entry.Value
-		}
-		for _, entry := range right.Mapping {
-			if !documentNodesEqual(leftMap[entry.Key], entry.Value) {
-				return false
-			}
-		}
-	}
-	for i := range left.Sequence {
-		if !documentNodesEqual(left.Sequence[i], right.Sequence[i]) {
-			return false
-		}
-	}
-	return true
-}