Files
aquasecurity-trivy/pkg/licensing/expression/expression.go

97 lines
2.4 KiB
Go

package expression
import (
"strings"
"unicode"
"golang.org/x/xerrors"
)
var (
ErrInvalidExpression = xerrors.New("invalid expression error")
)
type NormalizeFunc func(license Expression) Expression
func parse(license string) (Expression, error) {
l := NewLexer(strings.NewReader(license))
if yyParse(l) != 0 {
return nil, xerrors.Errorf("license parse error: %w", l.Err())
} else if err := l.Err(); err != nil {
return nil, err
}
return l.result, nil
}
func Normalize(license string, funcs ...NormalizeFunc) (string, error) {
expr, err := parse(license)
if err != nil {
return "", xerrors.Errorf("license (%s) parse error: %w", license, err)
}
for _, fn := range funcs {
expr = normalize(expr, fn)
}
return expr.String(), nil
}
func normalize(expr Expression, fn NormalizeFunc) Expression {
// Apply normalization function first
normalized := fn(expr)
switch e := normalized.(type) {
case SimpleExpr:
// No further normalization for SimpleExpr
case CompoundExpr:
// Only recursively process if the result is a CompoundExpr
e.left = normalize(e.left, fn)
e.right = normalize(e.right, fn)
e.conjunction.literal = strings.ToUpper(e.conjunction.literal) // e.g. "and" => "AND"
return e
}
return normalized
}
// NormalizeForSPDX replaces ' ' to '-' in license-id.
// SPDX license MUST NOT have white space between a license-id.
// There MUST be white space on either side of the operator "WITH".
// ref: https://spdx.github.io/spdx-spec/v2.3/SPDX-license-expressions
func NormalizeForSPDX(expr Expression) Expression {
switch e := expr.(type) {
case SimpleExpr:
var b strings.Builder
for _, c := range e.License {
switch {
// spec: idstring = 1*(ALPHA / DIGIT / "-" / "." )
case isAlphabet(c) || unicode.IsNumber(c) || c == '-' || c == '.':
_, _ = b.WriteRune(c)
case c == ':':
// TODO: Support DocumentRef
_, _ = b.WriteRune(c)
default:
// Replace invalid characters with '-'
_, _ = b.WriteRune('-')
}
}
return SimpleExpr{License: b.String(), HasPlus: e.HasPlus}
case CompoundExpr:
if e.Conjunction() == TokenWith {
initSpdxExceptions()
// Use correct SPDX exceptionID
if exc, ok := spdxExceptions[strings.ToUpper(e.Right().String())]; ok {
return NewCompoundExpr(e.Left(), e.Conjunction(), exc)
}
}
}
return expr
}
func isAlphabet(r rune) bool {
if (r < 'a' || r > 'z') && (r < 'A' || r > 'Z') {
return false
}
return true
}