github.com/google/osv-scalibr@v0.4.1/semantic/version-cran.go (about)

     1  // Copyright 2025 Google LLC
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package semantic
    16  
    17  import (
    18  	"fmt"
    19  	"math/big"
    20  	"strings"
    21  )
    22  
    23  // cranVersion is the representation of a version of a package that is held
    24  // in the CRAN ecosystem (https://cran.r-project.org/).
    25  //
    26  // A version is a sequence of at least two non-negative integers separated by
    27  // either a period or a dash.
    28  //
    29  // See https://astrostatistics.psu.edu/su07/R/html/base/html/package_version.html
    30  type cranVersion struct {
    31  	components components
    32  }
    33  
    34  func (v cranVersion) compare(w cranVersion) int {
    35  	if diff := v.components.Cmp(w.components); diff != 0 {
    36  		return diff
    37  	}
    38  
    39  	// versions are only equal if they also have the same number of components,
    40  	// otherwise the longer one is considered greater
    41  	if len(v.components) == len(w.components) {
    42  		return 0
    43  	}
    44  
    45  	if len(v.components) > len(w.components) {
    46  		return 1
    47  	}
    48  
    49  	return -1
    50  }
    51  
    52  func (v cranVersion) CompareStr(str string) (int, error) {
    53  	w, err := parseCRANVersion(str)
    54  
    55  	if err != nil {
    56  		return 0, err
    57  	}
    58  
    59  	return v.compare(w), nil
    60  }
    61  
    62  func parseCRANVersion(str string) (cranVersion, error) {
    63  	// for now, treat an empty version string as valid
    64  	if str == "" {
    65  		return cranVersion{}, nil
    66  	}
    67  
    68  	// dashes and periods have the same weight, so we can just normalize to periods
    69  	parts := strings.Split(strings.ReplaceAll(str, "-", "."), ".")
    70  
    71  	comps := make(components, 0, len(parts))
    72  
    73  	for _, s := range parts {
    74  		v, ok := new(big.Int).SetString(s, 10)
    75  
    76  		if !ok {
    77  			return cranVersion{}, fmt.Errorf("%w: '%s' is not allowed", ErrInvalidVersion, str)
    78  		}
    79  
    80  		comps = append(comps, v)
    81  	}
    82  
    83  	return cranVersion{comps}, nil
    84  }