forked from google/go-licenses
/
find.go
95 lines (89 loc) · 2.82 KB
/
find.go
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// Copyright 2019 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 licenses
import (
"errors"
"fmt"
"os"
"path/filepath"
"regexp"
"strings"
)
var (
licenseRegexp = regexp.MustCompile(`^(?i)((UN)?LICEN(S|C)E|COPYING|README|NOTICE).*$`)
)
// Find returns the file path of the license for this package.
//
// dir is path of the directory where we want to find a license.
// rootDir is path of the module containing this package. Find will not search out of the
// rootDir.
func Find(dir string, rootDir string, classifier Classifier) (string, error) {
dir, err := filepath.Abs(dir)
if err != nil {
return "", err
}
rootDir, err = filepath.Abs(rootDir)
if err != nil {
return "", err
}
if !strings.HasPrefix(dir, rootDir) {
return "", fmt.Errorf("licenses.Find: rootDir %s should contain dir %s", rootDir, dir)
}
found, err := findUpwards(dir, licenseRegexp, rootDir, func(path string) bool {
// TODO(RJPercival): Return license details
if _, _, err := classifier.Identify(path); err != nil {
return false
}
return true
})
if err != nil {
if errors.Is(err, errNotFound) {
return "", fmt.Errorf("cannot find a known open source license for %q whose name matches regexp %s and locates up until %q", dir, licenseRegexp, rootDir)
}
return "", fmt.Errorf("finding a known open source license: %w", err)
}
return found, nil
}
var errNotFound = fmt.Errorf("file/directory matching predicate and regexp not found")
func findUpwards(dir string, r *regexp.Regexp, stopAt string, predicate func(path string) bool) (string, error) {
// Dir must be made absolute for reliable matching with stopAt regexps
dir, err := filepath.Abs(dir)
if err != nil {
return "", err
}
start := dir
// Stop once we go out of the stopAt dir.
for strings.HasPrefix(dir, stopAt) {
dirContents, err := os.ReadDir(dir)
if err != nil {
return "", err
}
for _, f := range dirContents {
if r.MatchString(f.Name()) {
path := filepath.Join(dir, f.Name())
if predicate != nil && !predicate(path) {
continue
}
return path, nil
}
}
parent := filepath.Dir(dir)
if parent == dir {
// Can't go any higher up the directory tree.
break
}
dir = parent
}
return "", fmt.Errorf("findUpwards(dir=%q, regexp=%q, stopAt=%q, predicate=func): %w", start, r, stopAt, errNotFound)
}