terraform/plugin/discovery/version_set.go

85 lines
2.4 KiB
Go

package discovery
import (
"sort"
version "github.com/hashicorp/go-version"
)
// A ConstraintStr is a string containing a possibly-invalid representation
// of a version constraint provided in configuration. Call Parse on it to
// obtain a real Constraint object, or discover that it is invalid.
type ConstraintStr string
// Parse transforms a ConstraintStr into a Constraints if it is
// syntactically valid. If it isn't then an error is returned instead.
func (s ConstraintStr) Parse() (Constraints, error) {
raw, err := version.NewConstraint(string(s))
if err != nil {
return Constraints{}, err
}
return Constraints{raw}, nil
}
// MustParse is like Parse but it panics if the constraint string is invalid.
func (s ConstraintStr) MustParse() Constraints {
ret, err := s.Parse()
if err != nil {
panic(err)
}
return ret
}
// Constraints represents a set of versions which any given Version is either
// a member of or not.
type Constraints struct {
raw version.Constraints
}
// AllVersions is a Constraints containing all versions
var AllVersions Constraints
func init() {
AllVersions = Constraints{
raw: make(version.Constraints, 0),
}
}
// Allows returns true if the given version permitted by the receiving
// constraints set.
func (s Constraints) Allows(v Version) bool {
return s.raw.Check(v.raw)
}
// Append combines the receiving set with the given other set to produce
// a set that is the intersection of both sets, which is to say that resulting
// constraints contain only the versions that are members of both.
func (s Constraints) Append(other Constraints) Constraints {
raw := make(version.Constraints, 0, len(s.raw)+len(other.raw))
// Since "raw" is a list of constraints that remove versions from the set,
// "Intersection" is implemented by concatenating together those lists,
// thus leaving behind only the versions not removed by either list.
raw = append(raw, s.raw...)
raw = append(raw, other.raw...)
// while the set is unordered, we sort these lexically for consistent output
sort.Slice(raw, func(i, j int) bool {
return raw[i].String() < raw[j].String()
})
return Constraints{raw}
}
// String returns a string representation of the set members as a set
// of range constraints.
func (s Constraints) String() string {
return s.raw.String()
}
// Unconstrained returns true if and only if the receiver is an empty
// constraint set.
func (s Constraints) Unconstrained() bool {
return len(s.raw) == 0
}