3 files changed, 181 insertions, 0 deletions
diff --git a/vendor/github.com/authzed/spicedb/pkg/cursor/cursor.go b/vendor/github.com/authzed/spicedb/pkg/cursor/cursor.go
new file mode 100644
index 0000000..4233efa
--- /dev/null
+++ b/vendor/github.com/authzed/spicedb/pkg/cursor/cursor.go
@@ -0,0 +1,133 @@
+package cursor
+
+import (
+	"encoding/base64"
+	"errors"
+	"fmt"
+
+	v1 "github.com/authzed/authzed-go/proto/authzed/api/v1"
+
+	"github.com/authzed/spicedb/pkg/datastore"
+	dispatch "github.com/authzed/spicedb/pkg/proto/dispatch/v1"
+	impl "github.com/authzed/spicedb/pkg/proto/impl/v1"
+	"github.com/authzed/spicedb/pkg/spiceerrors"
+)
+
+// Encode converts a decoded cursor to its opaque version.
+func Encode(decoded *impl.DecodedCursor) (*v1.Cursor, error) {
+	marshalled, err := decoded.MarshalVT()
+	if err != nil {
+		return nil, NewInvalidCursorErr(fmt.Errorf(errEncodeError, err))
+	}
+
+	return &v1.Cursor{
+		Token: base64.StdEncoding.EncodeToString(marshalled),
+	}, nil
+}
+
+// Decode converts an encoded cursor to its decoded version.
+func Decode(encoded *v1.Cursor) (*impl.DecodedCursor, error) {
+	if encoded == nil {
+		return nil, NewInvalidCursorErr(errors.New("cursor pointer was nil"))
+	}
+
+	decodedBytes, err := base64.StdEncoding.DecodeString(encoded.Token)
+	if err != nil {
+		return nil, NewInvalidCursorErr(fmt.Errorf(errDecodeError, err))
+	}
+
+	decoded := &impl.DecodedCursor{}
+	if err := decoded.UnmarshalVT(decodedBytes); err != nil {
+		return nil, NewInvalidCursorErr(fmt.Errorf(errDecodeError, err))
+	}
+
+	return decoded, nil
+}
+
+// EncodeFromDispatchCursor encodes an internal dispatching cursor into a V1 cursor for external
+// consumption, including the provided call context to ensure the API cursor reflects the calling
+// API method. The call hash should contain all the parameters of the calling API function,
+// as well as its revision and name.
+func EncodeFromDispatchCursor(dispatchCursor *dispatch.Cursor, callAndParameterHash string, revision datastore.Revision, flags map[string]string) (*v1.Cursor, error) {
+	if dispatchCursor == nil {
+		return nil, spiceerrors.MustBugf("got nil dispatch cursor")
+	}
+
+	return Encode(&impl.DecodedCursor{
+		VersionOneof: &impl.DecodedCursor_V1{
+			V1: &impl.V1Cursor{
+				Revision:              revision.String(),
+				DispatchVersion:       dispatchCursor.DispatchVersion,
+				Sections:              dispatchCursor.Sections,
+				CallAndParametersHash: callAndParameterHash,
+				Flags:                 flags,
+			},
+		},
+	})
+}
+
+// GetCursorFlag retrieves a flag from an encoded API cursor, if any.
+func GetCursorFlag(encoded *v1.Cursor, flagName string) (string, bool, error) {
+	decoded, err := Decode(encoded)
+	if err != nil {
+		return "", false, err
+	}
+
+	v1decoded := decoded.GetV1()
+	if v1decoded == nil {
+		return "", false, NewInvalidCursorErr(ErrNilCursor)
+	}
+
+	value, ok := v1decoded.Flags[flagName]
+	return value, ok, nil
+}
+
+// DecodeToDispatchCursor decodes an encoded API cursor into an internal dispatching cursor,
+// ensuring that the provided call context matches that encoded into the API cursor. The call
+// hash should contain all the parameters of the calling API function, as well as its revision
+// and name.
+func DecodeToDispatchCursor(encoded *v1.Cursor, callAndParameterHash string) (*dispatch.Cursor, map[string]string, error) {
+	decoded, err := Decode(encoded)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	v1decoded := decoded.GetV1()
+	if v1decoded == nil {
+		return nil, nil, NewInvalidCursorErr(ErrNilCursor)
+	}
+
+	if v1decoded.CallAndParametersHash != callAndParameterHash {
+		return nil, nil, NewInvalidCursorErr(ErrHashMismatch)
+	}
+
+	return &dispatch.Cursor{
+		DispatchVersion: v1decoded.DispatchVersion,
+		Sections:        v1decoded.Sections,
+	}, v1decoded.Flags, nil
+}
+
+// DecodeToDispatchRevision decodes an encoded API cursor into an internal dispatch revision.
+// NOTE: this method does *not* verify the caller's method signature.
+func DecodeToDispatchRevision(encoded *v1.Cursor, ds revisionDecoder) (datastore.Revision, error) {
+	decoded, err := Decode(encoded)
+	if err != nil {
+		return nil, err
+	}
+
+	v1decoded := decoded.GetV1()
+	if v1decoded == nil {
+		return nil, ErrNilCursor
+	}
+
+	parsed, err := ds.RevisionFromString(v1decoded.Revision)
+	if err != nil {
+		return datastore.NoRevision, fmt.Errorf(errDecodeError, err)
+	}
+
+	return parsed, nil
+}
+
+type revisionDecoder interface {
+	RevisionFromString(string) (datastore.Revision, error)
+}
diff --git a/vendor/github.com/authzed/spicedb/pkg/cursor/doc.go b/vendor/github.com/authzed/spicedb/pkg/cursor/doc.go
new file mode 100644
index 0000000..bddf5cd
--- /dev/null
+++ b/vendor/github.com/authzed/spicedb/pkg/cursor/doc.go
@@ -0,0 +1,2 @@
+// Package cursor implements encoding and decoding of cursors used in various APIs.
+package cursor
diff --git a/vendor/github.com/authzed/spicedb/pkg/cursor/errors.go b/vendor/github.com/authzed/spicedb/pkg/cursor/errors.go
new file mode 100644
index 0000000..941df70
--- /dev/null
+++ b/vendor/github.com/authzed/spicedb/pkg/cursor/errors.go
@@ -0,0 +1,46 @@
+package cursor
+
+import (
+	"errors"
+
+	v1 "github.com/authzed/authzed-go/proto/authzed/api/v1"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"github.com/authzed/spicedb/pkg/spiceerrors"
+)
+
+// Public facing errors
+const (
+	errEncodeError = "error encoding cursor: %w"
+	errDecodeError = "error decoding cursor: %w"
+)
+
+// ErrNilCursor is returned as the base error when nil is provided as the
+// cursor argument to Decode
+var ErrNilCursor = errors.New("cursor pointer was nil")
+
+// ErrHashMismatch is returned as the base error when a mismatching hash was given to the decoder.
+var ErrHashMismatch = errors.New("the cursor provided does not have the same arguments as the original API call; please ensure you are making the same API call, with the exact same parameters (besides the cursor)")
+
+// InvalidCursorError occurs when a cursor could not be decoded.
+type InvalidCursorError struct {
+	error
+}
+
+// GRPCStatus implements retrieving the gRPC status for the error.
+func (err InvalidCursorError) GRPCStatus() *status.Status {
+	return spiceerrors.WithCodeAndDetails(
+		err,
+		codes.InvalidArgument,
+		spiceerrors.ForReason(
+			v1.ErrorReason_ERROR_REASON_INVALID_CURSOR,
+			nil,
+		),
+	)
+}
+
+// NewInvalidCursorErr creates and returns a new invalid cursor error.
+func NewInvalidCursorErr(err error) error {
+	return InvalidCursorError{err}
+}