You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: runfiles.go
    path of file: ./repos/rules_go/go/runfiles
    
    the code of the file until where you have to start completion: // Copyright 2020, 2021 Google LLC
//
// 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
//
//     https://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 runfiles provides access to Bazel runfiles.
//
// # Usage
//
// This package has two main entry points, the global functions Rlocation and Env,
// and the Runfiles type.
//
// # Global functions
//
// For s
    
func (r *Runfiles) Rlocation(path string) (string, error) {
	if r.impl == nil {
		return "", errors.New("runfiles: uninitialized Runfiles object")
	}

	if path == "" {
		return "", errors.New("runfiles: path may not be empty")
	}
	if err := isNormalizedPath(path); err != nil {
		return "", err
	}

	// See https://github.com/bazelbuild/bazel/commit/b961b0ad6cc2578b98d0a307581e23e73392ad02
	if strings.HasPrefix(path, `\`) {
		return "", fmt.Errorf("runfiles: path %q is absolute without a drive letter", path)
	}
	if filepath.IsAbs(path) {
		return path, nil
	}

	mappedPath := path
	split := strings.SplitN(path, "/", 2)
	if len(split) == 2 {
		key := repoMappingKey{r.sourceRepo, split[0]}
		if targetRepoDirectory, exists := r.repoMapping[key]; exists {
			mappedPath = targetRepoDirectory + "/" + split[1]
		}
	}

	p, err := r.impl.path(mappedPath)
	if err != nil {
		return "", Error{path, err}
	}
	return p, nil
}