Update GCS storage library to support GetObject API on gzipped objects (#6506)

Fixes #6280

vendor/google.golang.org/api/internal/settings.go

@@ -1,4 +1,4 @@
-// Copyright 2017 Google Inc. All Rights Reserved.
+// Copyright 2017 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -16,22 +16,47 @@
 package internal
 
 import (
+	"errors"
 	"net/http"
 
 	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
 	"google.golang.org/grpc"
 )
 
 // DialSettings holds information needed to establish a connection with a
 // Google API service.
 type DialSettings struct {
-	Endpoint                   string
-	Scopes                     []string
-	ServiceAccountJSONFilename string // if set, TokenSource is ignored.
-	TokenSource                oauth2.TokenSource
-	UserAgent                  string
-	APIKey                     string
-	HTTPClient                 *http.Client
-	GRPCDialOpts               []grpc.DialOption
-	GRPCConn                   *grpc.ClientConn
+	Endpoint        string
+	Scopes          []string
+	TokenSource     oauth2.TokenSource
+	Credentials     *google.DefaultCredentials
+	CredentialsFile string // if set, Token Source is ignored.
+	UserAgent       string
+	APIKey          string
+	HTTPClient      *http.Client
+	GRPCDialOpts    []grpc.DialOption
+	GRPCConn        *grpc.ClientConn
+	NoAuth          bool
+}
+
+// Validate reports an error if ds is invalid.
+func (ds *DialSettings) Validate() error {
+	hasCreds := ds.APIKey != "" || ds.TokenSource != nil || ds.CredentialsFile != "" || ds.Credentials != nil
+	if ds.NoAuth && hasCreds {
+		return errors.New("options.WithoutAuthentication is incompatible with any option that provides credentials")
+	}
+	// Credentials should not appear with other options.
+	// We currently allow TokenSource and CredentialsFile to coexist.
+	// TODO(jba): make TokenSource & CredentialsFile an error (breaking change).
+	if ds.Credentials != nil && (ds.APIKey != "" || ds.TokenSource != nil || ds.CredentialsFile != "") {
+		return errors.New("multiple credential options provided")
+	}
+	if ds.HTTPClient != nil && ds.GRPCConn != nil {
+		return errors.New("WithHTTPClient is incompatible with WithGRPCConn")
+	}
+	if ds.HTTPClient != nil && ds.GRPCDialOpts != nil {
+		return errors.New("WithHTTPClient is incompatible with gRPC dial options")
+	}
+	return nil
 }