internal/str/path.go

// Copyright 2018 The CUE Authors
//
// 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 str

import (
	"path/filepath"
	"strings"
)

// HasPath reports whether the slash-separated path s
// begins with the elements in prefix.
func HasPathPrefix(s, prefix string) bool {
	if len(s) == len(prefix) {
		return s == prefix
	}
	if prefix == "" {
		return true
	}
	if len(s) > len(prefix) {
		if prefix[len(prefix)-1] == '/' || s[len(prefix)] == '/' {
			return s[:len(prefix)] == prefix
		}
	}
	return false
}

// HasFilePathPrefix reports whether the filesystem path s
// begins with the elements in prefix.
func HasFilePathPrefix(s, prefix string) bool {
	sv := strings.ToUpper(filepath.VolumeName(s))
	pv := strings.ToUpper(filepath.VolumeName(prefix))
	s = s[len(sv):]
	prefix = prefix[len(pv):]
	switch {
	default:
		return false
	case sv != pv:
		return false
	case len(s) == len(prefix):
		return s == prefix
	case prefix == "":
		return true
	case len(s) > len(prefix):
		if prefix[len(prefix)-1] == filepath.Separator {
			return strings.HasPrefix(s, prefix)
		}
		return s[len(prefix)] == filepath.Separator && s[:len(prefix)] == prefix
	}
}