Vendor dependencies for GCS

vendor/cloud.google.com/go/spanner/errors.go

@@ -0,0 +1,108 @@
+/*
+Copyright 2017 Google Inc. All Rights Reserved.
+
+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 spanner
+
+import (
+	"fmt"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
+)
+
+// Error is the structured error returned by Cloud Spanner client.
+type Error struct {
+	// Code is the canonical error code for describing the nature of a
+	// particular error.
+	Code codes.Code
+	// Desc explains more details of the error.
+	Desc string
+	// trailers are the trailers returned in the response, if any.
+	trailers metadata.MD
+}
+
+// Error implements error.Error.
+func (e *Error) Error() string {
+	if e == nil {
+		return fmt.Sprintf("spanner: OK")
+	}
+	return fmt.Sprintf("spanner: code = %q, desc = %q", e.Code, e.Desc)
+}
+
+// decorate decorates an existing spanner.Error with more information.
+func (e *Error) decorate(info string) {
+	e.Desc = fmt.Sprintf("%v, %v", info, e.Desc)
+}
+
+// spannerErrorf generates a *spanner.Error with the given error code and
+// description.
+func spannerErrorf(ec codes.Code, format string, args ...interface{}) error {
+	return &Error{
+		Code: ec,
+		Desc: fmt.Sprintf(format, args...),
+	}
+}
+
+// toSpannerError converts general Go error to *spanner.Error.
+func toSpannerError(err error) error {
+	return toSpannerErrorWithMetadata(err, nil)
+}
+
+// toSpannerErrorWithMetadata converts general Go error and grpc trailers to *spanner.Error.
+// Note: modifies original error if trailers aren't nil
+func toSpannerErrorWithMetadata(err error, trailers metadata.MD) error {
+	if err == nil {
+		return nil
+	}
+	if se, ok := err.(*Error); ok {
+		if trailers != nil {
+			se.trailers = metadata.Join(se.trailers, trailers)
+		}
+		return se
+	}
+	if grpc.Code(err) == codes.Unknown {
+		return &Error{codes.Unknown, err.Error(), trailers}
+	}
+	return &Error{grpc.Code(err), grpc.ErrorDesc(err), trailers}
+}
+
+// ErrCode extracts the canonical error code from a Go error.
+func ErrCode(err error) codes.Code {
+	se, ok := toSpannerError(err).(*Error)
+	if !ok {
+		return codes.Unknown
+	}
+	return se.Code
+}
+
+// ErrDesc extracts the Cloud Spanner error description from a Go error.
+func ErrDesc(err error) string {
+	se, ok := toSpannerError(err).(*Error)
+	if !ok {
+		return err.Error()
+	}
+	return se.Desc
+}
+
+// errTrailers extracts the grpc trailers if present from a Go error.
+func errTrailers(err error) metadata.MD {
+	se, ok := err.(*Error)
+	if !ok {
+		return nil
+	}
+	return se.trailers
+}