adjust the toolkit to the new location

toolkit/server/extargs/custom.go

@@ -0,0 +1,85 @@
+package extargs
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/ipld/go-ipld-prime"
+	"github.com/ipld/go-ipld-prime/datamodel"
+	"github.com/ipld/go-ipld-prime/fluent/qp"
+	"github.com/ipld/go-ipld-prime/node/basicnode"
+
+	"github.com/ucan-wg/go-ucan/pkg/args"
+	"github.com/ucan-wg/go-ucan/pkg/policy"
+)
+
+type CustomExtArgs struct {
+	key          string
+	pol          policy.Policy
+	originalArgs args.ReadOnly
+	assembler    func(ma datamodel.MapAssembler)
+
+	once     sync.Once
+	args     *args.Args
+	argsIpld ipld.Node
+}
+
+func NewCustomExtArgs(key string, pol policy.Policy, assembler func(ma datamodel.MapAssembler)) *CustomExtArgs {
+	return &CustomExtArgs{key: key, pol: pol, assembler: assembler}
+}
+
+func (cea *CustomExtArgs) Verify() error {
+	if err := cea.makeArgs(); err != nil {
+		return err
+	}
+
+	// Note: CustomExtArgs doesn't support verifying a hash computed client-side like the other
+	// external args, as the arguments are by nature dynamic. The client can't generate a meaningful hash.
+
+	ok, leaf := cea.pol.PartialMatch(cea.argsIpld)
+	if !ok {
+		return fmt.Errorf("the following UCAN policy is not satisfied: %v", leaf.String())
+	}
+	return nil
+}
+
+func (cea *CustomExtArgs) Args() (*args.Args, error) {
+	if err := cea.makeArgs(); err != nil {
+		return nil, err
+	}
+	return cea.args, nil
+}
+
+func (cea *CustomExtArgs) makeArgs() error {
+	var outerErr error
+	cea.once.Do(func() {
+		var err error
+
+		cea.args, err = makeCustomArgs(cea.key, cea.assembler)
+		if err != nil {
+			outerErr = err
+			return
+		}
+
+		cea.argsIpld, err = cea.args.ToIPLD()
+		if err != nil {
+			outerErr = err
+			return
+		}
+	})
+	return outerErr
+}
+
+func makeCustomArgs(key string, assembler func(ma datamodel.MapAssembler)) (*args.Args, error) {
+	n, err := qp.BuildMap(basicnode.Prototype.Any, -1, assembler)
+	if err != nil {
+		return nil, err
+	}
+
+	res := args.New()
+	err = res.Add(key, n)
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
+}