node.go

package typed

import (
	"fmt"
	"path"

	"github.com/ipld/go-ipld-prime"
)

type Node struct {
	// FUTURE: proxies most methods, plus adds just-in-time type checking on reads.
	// You can use a Validate call to force checking of the entire tree.
	// "Advanced Layouts" (e.g. HAMTs, etc) can be seamlessly presented as a plain map through this interface.
}

type MutableNode struct {
	// FUTURE: another impl of ipld.MutableNode we can return which checks all things at change time.
	// This can proxy to some other implementation type that does real storage.
}

func Validate(ts Universe, t Type, node ipld.Node) []error {
	return validate(ts, t, node, "/")
}

// review: 'ts' param might not actually be necessary; everything relevant can be reached from t so far.
func validate(ts Universe, t Type, node ipld.Node, pth string) []error {
	switch t2 := t.(type) {
	case TypeBool:
		if node.Kind() != ipld.ReprKind_Bool {
			return []error{fmt.Errorf("Schema match failed: expected type %q (which is kind %v) at path %q, but found kind %v", t2.Name, t.ReprKind(), pth, node.Kind())}
		}
		return nil
	case TypeString:
		if node.Kind() != ipld.ReprKind_String {
			return []error{fmt.Errorf("Schema match failed: expected type %q (which is kind %v) at path %q, but found kind %v", t2.Name, t.ReprKind(), pth, node.Kind())}
		}
		return nil
	case TypeBytes:
		if node.Kind() != ipld.ReprKind_Bytes {
			return []error{fmt.Errorf("Schema match failed: expected type %q (which is kind %v) at path %q, but found kind %v", t2.Name, t.ReprKind(), pth, node.Kind())}
		}
		return nil
	case TypeInt:
		if node.Kind() != ipld.ReprKind_Int {
			return []error{fmt.Errorf("Schema match failed: expected type %q (which is kind %v) at path %q, but found kind %v", t2.Name, t.ReprKind(), pth, node.Kind())}
		}
		return nil
	case TypeFloat:
		if node.Kind() != ipld.ReprKind_Float {
			return []error{fmt.Errorf("Schema match failed: expected type %q (which is kind %v) at path %q, but found kind %v", t2.Name, t.ReprKind(), pth, node.Kind())}
		}
		return nil
	case TypeMap:
		if node.Kind() != ipld.ReprKind_Map {
			return []error{fmt.Errorf("Schema match failed: expected type %q (which is kind %v) at path %q, but found kind %v", t2.Name, t.ReprKind(), pth, node.Kind())}
		}
		keys, _ := node.Keys()
		errs := []error(nil)
		for _, k := range keys {
			child, _ := node.TraverseField(k)
			if child.IsNull() {
				if !t2.ValueNullable {
					errs = append(errs, fmt.Errorf("Schema match failed: map at path %q contains unpermitted null in key %q", pth, k))
				}
			} else {
				errs = append(errs, validate(ts, t2.ValueType, child, path.Join(pth, k))...)
			}
		}
		return errs
	case TypeList:
	case TypeLink:
	case TypeUnion:
		// TODO *several* interesting errors
	case TypeObject:
	case TypeEnum:
		// TODO another interesting error
	}
	return nil
}